be longer and possess a larger curvature. On reaching the post-nasal
space, its beak is turned round so as to point towards the outer canthus
of the eye on the affected side. It may be necessary to alter the curve
more than once in order to get the point of the catheter to exactly
engage into the orifice of the Eustachian tube.
If both sides be completely obstructed, the only method to adopt is
catheterization from the mouth. The ordinary catheter is used. It is
passed into the mouth, its beak being directed upwards, until it reaches
the posterior wall of the pharynx. The catheter is then pushed directly
upwards until its stem impinges against the soft palate. The beak is
then turned outwards until it lies almost horizontally. In this position
it should enter Rosenmüller’s fossa. The catheter is now withdrawn a
little and should be felt to pass over a slight obstruction--the
posterior lip of the Eustachian orifice. By gently pressing the beak
slightly outwards, it should engage within the entrance of the
Eustachian canal.
4. _Obstruction within the post-nasal space._ A common error in
introducing the catheter is to push it too far backwards, so that on
rotation of the beak outwards it passes behind the Eustachian tube and
lies in Rosenmüller’s fossa. In this position the sounds referred to the
examiner’s ear through the auscultation tube during the act of inflation
differ from the normal sounds in that they are soft and distant. In a
case of doubt inflation should again be practised with the catheter in
varying positions. If the catheter be in the correct position, the
patient should be able to talk without discomfort, and there should be
no tendency to retching or coughing. If, however, the beak lies in
Rosenmüller’s fossa, considerable irritation is caused, and on inflation
the patient feels the air in the throat and not in the ear.
Catheterization may be rendered difficult by the presence of a large pad
of adenoids or of a tumour; or inflation of air into the Eustachian tube
may be quite impossible owing to the occlusion of its pharyngeal
orifice, the result of scarring.
=Mishaps.= 1. _Rupture of the tympanic membrane._ With a normal membrane
this is difficult to produce, in spite of even forcible inflation. Such
an accident usually occurs at the site of some previous scar or atrophic
patch in the membrane. If it occurs, there may be a temporary feeling of
giddiness, noises, and pain in the ear. Inflation, of course, should be
stopped at once and the ear protected for a day or two by plugging the
meatus with a piece of cotton-wool.
2. _Severe epistaxis._ This is usually the result of trying to force the
catheter through an obstructed nose, but it may also take place, though
rarely, when manipulations have been carried out in a gentle fashion.
3. _Syncope._ This is fortunately of rare occurrence and usually only
happens on the first occasion that the catheter is passed. For this
reason the patient should always be in a sitting posture, and on the
slightest appearance of pallor or faintness the catheter should be
withdrawn. The attack invariably passes off, but for the moment it is
very unpleasant.
4. _Surgical emphysema._ If the point of the catheter lacerates the
mucous membrane, the air may be forced into the submucous tissue. This
mishap, however, rarely occurs as the result of simple catheterization,
but is more likely to follow forcible attempts to pass a bougie into the
Eustachian tube.
PASSING OF THE EUSTACHIAN BOUGIE
=Indications.= This may be done for the following reasons:--
(i) As a means of diagnosis, to demonstrate the existence and position
of a stricture.
(ii) To dilate a stricture.
(iii) As a therapeutic measure, to treat the mucous membrane of the
Eustachian tube by means of a medicated bougie.
Bougies are made of various materials, but for ordinary purposes the
gum-elastic is the best. They are about 7 inches in length with a
slightly bulbous point.
In the adult the length of the Eustachian tube is approximately 1-1/2
inches, of which 1 inch forms the cartilaginous and 1/2 inch the osseous
portion. The narrowest part of its lumen is known as the isthmus, and is
situated at the junction of its cartilaginous and bony portion. On
passing the bougie through the catheter into the Eustachian tube, it is
essential to know how far its point is projecting beyond the point of
the catheter. For this purpose the bougie may be marked at its outer
extremity. Five inches from the point of the bougie, that is, the same
length as the catheter, is a black band a centimetre in length; a
centimetre farther up is another black band; and again after an
intervening space of a centimetre is a third black band (Fig. 214).
[Illustration: FIG. 214. AUTHOR’S GRADUATED EUSTACHIAN BOUGIE.]
=Technique.= The catheter is introduced in the ordinary way, and its
position within the entrance of the Eustachian orifice is verified by
means of inflation. It is kept fixed with the left hand, and the bougie
is pushed into the catheter until the beginning of the first mark on the
former just reaches the outer extremity of the latter; the tip of the
bougie will now be flush with the point of the catheter. If there be no
pain and no resistance, the bougie is very gently pushed on until the
beginning of its second black band just enters the catheter. Its point
will now project 2 centimetres within the Eustachian tube; that is, to
about the region of the isthmus. If the bougie has been successfully
introduced into the Eustachian tube, the patient generally states that
the instrument is felt within the ear itself. No force should be used
for fear of making a false passage, and with gentle manipulation it is
very rare for actual pain to occur. On reaching the isthmus resistance
may be met with, but by the exercise of slight pressure the bougie can
usually be made to pass through it; if there be much resistance the
bougie should be withdrawn and a finer one substituted. After passing
through the isthmus, the bougie may be pushed in another centimetre, but
no further, in case it may actually enter and injure the contents of the
tympanic cavity.
After the tip of the bougie has passed through the isthmus the surgeon
will hear its movements through the auscultation tube as a rub or
crackling sound. It is left in position for five or ten minutes and
then withdrawn. The ear should then be gently inflated, when the air
entry into the tympanic cavity will probably be found to be much more
free.
As the passage of the bougie causes a certain amount of reaction, it
should not be passed oftener than once a week. Although no force should
ever be employed, the largest possible bougie should be passed at each
successive sitting until complete dilatation has been obtained.
=Difficulties.= 1. If the catheter be not in position, the bougie may
pass behind the tip of the Eustachian orifice and enter Rosenmüller’s
fossa. This can usually be felt by the patient as a pricking sensation
in the throat, and may produce retching and coughing.
2. A stricture of the Eustachian tube may be so great as to prevent
entrance of the bougie.
=Dangers.= (_a_) Surgical emphysema. If the mucous membrane be lacerated
by the bougie, air may be forced into the subcutaneous tissues on
inflation, after its withdrawal. In some cases the surgical emphysema is
so considerable as to involve the side of the neck and face, and indeed
has been known to necessitate the performance of laryngotomy.
The best treatment is to make the patient suck ice and to forbid all
attempts at blowing the nose and coughing. Sometimes it is also
necessary to scarify the pharynx and soft palate with a small bistoury.
Recovery may be hastened by gentle massage of the neck and face.
Inflation should not be attempted again for at least a week.
(_b_) The bougie may be pushed in too far and cause injury to the
contents of the tympanic cavity.
(_c_) The tip of the bougie may break off whilst in the Eustachian tube.
With a gum-elastic bougie this is very rare, but it is more likely to
occur if the brittle celluloid bougies are used. To prevent this
unfortunate disaster the bougie should be carefully examined before
passing it, to see that it is not cracked nor broken. If such an
accident does happen it is wiser to do nothing, because as a rule the
fragment is afterwards expelled spontaneously.
=Results.= If the obstruction be fairly recent and limited to the
pharyngeal end of the Eustachian tube, excellent results may be obtained
by using either the simple bougie or the catgut variety moistened with a
5% solution of silver nitrate.
Owing to the general thickening of the tube, there is a marked tendency
for further stricture to take place in the more chronic cases, even if a
temporary improvement is obtained, and for this reason the use of the
bougie is seldom to be recommended.
WASHING OUT THE TYMPANIC CAVITY THROUGH THE EUSTACHIAN TUBE
=Indications.= (i) In chronic middle-ear suppuration in which the
perforation is situated in the anterior inferior quadrant and the
continuance of the otorrhœa is apparently due to the secretion not being
able to drain from the tympanic cavity. This method may be employed to
effect drainage and in order to cleanse the tympanic cavity thoroughly
before the instillation of medicated drops. In these cases the floor of
the tympanic cavity is usually at a considerable depth beneath the lower
limit of the membrane (Fig. 186).
(ii) In order to remove a small foreign body lying on the floor of the
tympanic cavity which cannot be expelled by syringing. The operation is
only tentative and is seldom successful.
=Contra-indications.= (i) If there be acute middle-ear suppuration; (ii)
if the perforation be very small, as there will be a considerable risk
of the fluid being driven into the mastoid antrum and further infecting
it.
=Technique.= A catheter of wide calibre is passed in the ordinary
manner. Inflation is practised to see if it is in the right position.
The left hand fixes the outer extremity of the catheter at its entrance
within the nose and keeps it in position. The patient inclines the head
over to the affected side and holds a receiver beneath the ear. A small
brass syringe whose nozzle accurately fits the outer extremity of the
catheter is used. Slight force may be required during the act of
syringing, but must not be sufficient to cause pain within the ear. A
certain amount of fluid always escapes into the throat although the
catheter is in its right position, and this may set up an attack of
retching and coughing. To avoid this the patient should incline his head
slightly forward as well as to the affected side and breathe gently with
the mouth open. If the manipulation be successful the fluid will trickle
out of the external meatus.
A foreign body is rarely expelled by this method, as the force of fluid
syringed into the Eustachian tube is seldom sufficient, and it is not
wise to use too great pressure. In order to expel all the fluid from the
tympanic cavity, the ear is afterwards inflated by Politzer’s method,
and at the same time the fluid is mopped out of the ear by means of
pledgets of cotton-wool.
=Results.= If the continuance of the middle-ear suppuration has been
chiefly due to the retention of the purulent secretion in the lower part
of the tympanic cavity, this method of treatment is frequently most
satisfactory. In other cases no benefit is obtained owing to the
suppuration being due to other causes.
=Dangers.= The chief danger is the infection of the mastoid cells.
CHAPTER V
OPERATIONS UPON THE MASTOID PROCESS: WILDE’S INCISION AND SCHWARTZE’S
OPERATION
With few exceptions the conditions requiring operative procedures on the
mastoid process are the result of some suppurative lesion which has
originated within the tympanic cavity.
The object of such operations is to arrest or eradicate the disease
which, by further extension through the bony walls of the temporal bone,
might eventually cause death by giving rise to some suppurative
intracranial complication.
For their successful performance a knowledge of the anatomical
relationships of the mastoid process is essential. It is sufficient here
to remind the reader of the main surgical points in this connexion (Fig.
215).
SURGICAL ANATOMY OF THE MASTOID AREA
=The mastoid antrum.= At birth the mastoid antrum is almost fully
developed. In infancy it is situated superficially and at a much higher
level in relation to the auditory canal than in the adult. In the
infant, also, the petro-squamous and the squamo-mastoid suture are still
patent. As the mastoid cells develop, the antrum gradually becomes more
deeply placed, so that in the adult it is from half to three-quarters of
an inch from the surface.
Its roof, the tegmen tympani, is continuous with that of the attic.
Anteriorly it is separated from the external auditory meatus by the
posterior wall of the auditory canal, whose innermost margin forms the
outer wall of the aditus. On its inner wall lie the semicircular canals,
whilst posteriorly the lateral sinus is separated from it by an
intervening layer of mastoid cells or compact bone. Between the
semicircular canals and the lateral sinus is a small area composed of a
thin layer of bone, separating the antrum from the posterior fossa of
the cranial cavity.
=The mastoid process.= In the infant this is undeveloped and is merely
represented by a small bony protuberance. By the fourth year it has
practically reached the adult type.
Anatomically the mastoid process can be subdivided into three chief
types: (1) the pneumatic, in which the cells are few and large; (2) the
diploic, containing numerous small cells; and (3) the compact, in which
the bone is extremely dense. Mixed types are frequently found, the
cortex, as a rule, being more dense than the deeper portion.
Occasionally it is uniformly sclerosed, almost of the consistence of
ivory, but in these cases the condition is usually pathological, the
result of chronic inflammation of the mastoid process.
[Illustration: FIG. 215. LEFT TEMPORAL BONE, SHOWING ANATOMY OF THE
MIDDLE EAR AND MASTOID PROCESS. 1, Anterior wall of external meatus,
partly removed; 2, Canal for tensor tympani muscle, ending in processus
cochleariformis; 3, Attic; 4, Aditus; 5, External semicircular canal; 6,
Posterior root of zygoma; 7, Tegmen tympani; 8, Antrum; 9, Fallopian
canal for facial nerve; 9', Stylo-mastoid foramen; 10, Mastoid cells;
11, Fenestra rotunda; 12, Fenestra ovalis; 13, Promontory. Dotted line
shows outline of sigmoid groove for lateral sinus.]
The mastoid cells converge towards the antrum and may be divided into
two groups: (1) those extending vertically downwards to the tip of the
mastoid process; and (2) those lying between the antrum and the sigmoid
process of the lateral sinus. In addition to these two groups, it must
not be forgotten that cells may extend in other directions; for
instance, (_a_) anteriorly, along the root of the zygoma; (_b_)
posteriorly, communicating with the cells of the occipital bone; (_c_)
inferiorly, between the floor of the tympanic cavity and the jugular
fossa; (_d_) internally, spreading inwards towards the apex of the
petrous bone and surrounding the labyrinth; or (_e_) enveloping the
orifice of the Eustachian tube.
_The facial nerve_, after dipping beneath the external semicircular
canal, passes vertically downwards through the mastoid process to emerge
at the stylo-mastoid foramen. Entering this foramen and running along
the canal are the stylo-mastoid branches of the posterior auricular
artery. These vessels, if cut through by the chisel, may bleed in a
marked manner, thus drawing the attention of the operator to the fact
that he is in close proximity to the facial canal and nerve.
=Surface anatomy.= Although it is impossible to foretell with certainty
before operation what the anatomical structure of the mastoid process
may be, yet some information may be gathered from the formation of the
skull.
In the dolichocephalic type, the mastoid process is broad and frequently
contains large cells, especially at its tip and round the lateral sinus,
which is usually deeply placed. In the brachycephalic type, on the other
hand, there is a greater tendency for the mastoid process to be narrow
and to consist of dense bone, for the middle fossa to extend low down
and to overlap the outer wall of the antrum, and for the lateral sinus
to project forward and superficially, even to within 2 or 3 millimetres
of the posterior border of the external meatus.
The posterior root of the zygoma may be considered approximately the
line of demarcation between the roof of the antrum and mastoid process,
and the floor of the middle fossa of the skull. This, however, is only a
rough guide, as in some cases, especially of the brachycephalic type,
the middle fossa may dip below this point. If this ridge is not well
marked, then Reid’s base-line must be taken as the guide.
Just behind the auditory meatus, at its upper posterior margin, is the
spine of Henle, which forms the anterior boundary of the suprameatal
triangle. Macewen, who first described this triangle, gave it as a guide
for the exposure of the antrum. Experience, however, has shown that no
reliance can be placed on this as a landmark, as, if the bone is
chiselled through at this point, it is by no means uncommon to expose
the dura mater of the middle fossa. A point 10 millimetres (two-fifths
of an inch) behind the spine of Henle corresponds to the anterior border
of the sigmoid sinus. Behind the suprameatal triangle and beneath the
zygomatic ridge is the body of the mastoid process, which has a smooth
surface and is perforated by small foramina through which pass tiny
vessels.
The antrum, in the adult, is situated at a slightly higher level than
the tympanic membrane, its floor roughly corresponding with a line drawn
horizontally backwards through the middle of the posterior wall of the
bony meatus.
HISTORY OF THE MASTOID OPERATION
Although opening of the mastoid process as an operative measure dates
back to the eighteenth century, yet Schwartze, in 1873, was the first to
establish the operation as a practical procedure.
Schwartze’s operation consisted in the simple opening of the antrum and
mastoid cells, leaving the middle ear untouched. This procedure was
carried out no matter whether the disease was recent or long standing.
It soon became recognized, however, that this operation did not effect a
cure in all cases, more especially in those in which the disease
involved the walls of the tympanic cavity.
Küster, in 1889, suggested removal of the posterior wall of the external
auditory meatus, and about the same time von Bergmann advocated removal
of the outer attic-wall. The Küster-Bergmann operation, first practised
by Zaufal, may therefore be considered to be the origin of the complete
mastoid operation.
Stacke’s name is frequently though wrongly mentioned in association with
the complete operation, which is sometimes termed the Schwartze-Stacke
operation. Stacke’s operation was devised with a view to removal of the
ossicles and outer wall of the attic in those cases in which the bone
disease was limited to these regions. This operation, however, is
occasionally of service in the performance of the complete mastoid
operation (see p. 397).
Thus the year 1889 may be considered as the starting-point of the
complete mastoid operation. Since that date many modifications have been
introduced, the majority of which are not worthy of reference.
After the technique of the operation had been developed and practised
for some time, more careful attention was directed to the
after-treatment. In the earlier days of the radical operation it was the
rule to leave the wound open and to plug it with gauze, or to insert a
drainage tube which was carried through the membranous portion of the
external meatus.
The next step was the making of post-meatal skin flaps, with closure of
the posterior incision and packing of the wound through the auditory
canal; and the names most prominently associated with this are Panse,
Körner, and Stacke.
Still more recently, in order to shorten the after-treatment, the wound
cavity has been skin-grafted by the method first suggested by Siebenmann
and afterwards amplified by Charles Ballance.
The operations which will be considered are:--
1. Wilde’s incision.
2. Opening of the mastoid process and antrum.
3. The complete or radical mastoid operation.
Although definite indications for the above operations will be given, it
must be remembered that in many cases the extent of the operation will
depend very largely on the pathological condition found during the
course of the operation itself, as frequently the clinical symptoms are
not sufficient to determine beforehand what operation is indicated.
In comparing the simple opening of the mastoid cells and antrum with
that of the complete or radical operation, the fundamental difference is
that in the former the tympanic cavity and its contents are not
interfered with, whereas in the complete operation the middle ear,
antrum, and mastoid cells are converted into one large cavity. In
consequence, complete recovery of hearing may take place in the former
case; in the latter, however, this is not possible.
Although these operations, especially in the more acute conditions, are
performed from the point of view of saving the life of the patient, due
regard must also be given to the preservation or restoration of the
hearing power, if this indeed is possible. If the hearing power be very
poor, that is, if conversation cannot be heard more than 12 feet off,
and especially if the deafness be partially due to changes having
already taken place within the labyrinth, then the complete operation is
to be preferred if it be doubtful whether Schwartze’s operation will be
sufficient to eradicate the disease. If, on the other hand, the hearing
power of the affected ear be fairly good, and with this there is
deafness of the opposite side, then, unless it is absolutely essential
that the complete operation should be performed, an attempt should be
made to effect a cure by the simpler operation, provided it is first
explained to the patient that it may perhaps be necessary to perform the
complete operation afterwards.
WILDE’S INCISION
In cases of acute inflammation of the mastoid process or of a
subperiosteal abscess lying over it, Wilde made a post-aural incision,
incising the tissues down to the bone. The indications for doing this
are now considered to be very few, but it must be remembered that in
Wilde’s day the mastoid operation had not been developed.
=Indications.= (i) In infants it is sometimes justifiable, as the pus
may have escaped to the surface of the mastoid process either through
the squamo-mastoid suture or along the posterior wall of the auditory
canal, between the periosteum and bone, without there being any actual
disease of the bone.
(ii) As a temporary measure, to permit of drainage of a subperiosteal
abscess, if the operation on the mastoid process cannot be performed for
twenty-four hours or more.
(iii) In acute middle-ear suppuration a free incision down to the bone
may relieve the pain if there are symptoms of periostitis of the mastoid
process; it is, however, rarely necessary.
=Contra-indications.= In older children and adults (with the above
exceptions) this operation is not sufficient, as the periostitis or
subperiosteal abscess over the mastoid process is secondary to
underlying bone disease which can only be eradicated by an operation on
the mastoid process itself. Although healing may apparently take place,
fistulæ or other evidences of mastoid disease almost invariably occur
afterwards.
=Operation.= In an infant a general anæsthetic is not necessary, but in
an adult gas anæsthesia is advisable. The mastoid region is surgically
cleansed; the auricle is pulled forward and a free incision is carried
down to the bone, in a curved direction downwards over the mastoid
process. Originally Wilde made a vertical incision; but it is better, if
possible, that the incision should be the same as would be made in
performing the mastoid operation, which indeed will probably have to be
carried out afterwards. After the hæmorrhage has ceased and the purulent
contents of the abscess, if present, have drained away, fomentations
should be applied and changed frequently during the first twenty-four
hours. After this a simple dry dressing is sufficient.
=Results.= Except in the case of tiny infants, this procedure is seldom
successful in curing the condition, and must be considered as only a
temporary measure.
SCHWARTZE’S OPERATION
(Opening of the mastoid process and antrum)
=Indications.= (a) _In acute middle-ear suppuration._ (i) If, in spite
of free drainage, earache, pyrexia, and tenderness over the _body_ of
the mastoid do not abate within three days. This is all the more urgent
if the condition is the result of scarlet fever or influenza, as in
these cases the disease may spread with extreme rapidity.
(ii) If there be an obvious abscess over the mastoid process; except in
infants, in whom Wilde’s incision may be attempted as a tentative
measure, although it is not recommended.
(iii) If there be symptoms of meningeal irritation.
(iv) If a profuse otorrhœa has continued for over four weeks and is
accompanied by sagging downwards of the upper posterior wall of the
external meatus, a definite sign that the antrum is involved.
(v) If a profuse otorrhœa has continued for over eight weeks, with no
sign of abatement, even although the temperature may be normal and
although there may be no symptoms of inflammation of the mastoid
process. The continuance of the otorrhœa is presumably due to
accumulation of pus in a large antral cavity. The object of the
operation is to permit of free drainage and to prevent involvement of
the mastoid process itself. The question of operation, however, must be
considered very carefully. There is no doubt that in many cases
conservative measures may effect a cure even although the suppuration
has already existed for many months.
(_b_) _In chronic middle-ear suppuration._ Although the complete mastoid
operation is usually indicated, yet the simple opening of the mastoid
antrum may be advised under the following conditions, provided there are
no symptoms of inflammation of the mastoid process nor signs of disease
of the bony walls of the tympanic cavity:--
(i) If the perforation, however large, be surrounded by a rim of
tympanic membrane (showing that there is no disease of its bony
margins), and if the malleus be not adherent to the inner wall of the
tympanic cavity.
(ii) If the hearing be good, that is, if speech is heard farther off
than 12 feet, especially if the other ear (from whatever cause) be quite
deaf.
Politzer, among others, still maintains that there is frequently no
communication between the affected mastoid cells and the antrum if the
mastoid abscess is the result of acute middle-ear suppuration. For this
reason he considers that the antral cavity should only be opened if
there be definite evidence of bone disease between the abscess cavity
and the antrum, or if symptoms of extra-dural abscess or some
intracranial complication be present. It is, however, difficult to
believe that some communication, however microscopic, does not always
exist between the antrum and the mastoid cells, seeing that the latter
originally developed as outgrowths from the antrum itself, and must have
become infected by direct extension from it. At the same time there is
no doubt that complete recovery takes place in a certain number of cases
in which the antrum has not been opened.
In my opinion, however, it is always wiser in such cases to open the
antrum. Politzer considers that if this be done, healing does not take
place so rapidly as in those cases in which the antrum has not been
opened. On the other hand, if the antrum be not opened, the main object
of the operation, that is, free drainage of the contents of the aural
cavity, is not attained.
=Operation.= _Preparation of the patient._ The head should be shaved for
a space of 2 inches around the mastoid region, twenty-four hours before
the operation if possible. In women the hair in front of the ear,
instead of being shaved off, should be combed forward and plastered down
with carbolic soap. By doing this the hair can be arranged so as to
cover the bald area during convalescence, a matter of great satisfaction
to the patient.
The area of the operation and surrounding parts should be thoroughly
washed with ethereal soap solution and afterwards protected with a
compress of 1 in 2,000 solution of biniodide of mercury. After the
patient has been anæsthetized, the cleansing process should be repeated,
and the auditory canal syringed out with the lotion. The head is then
covered with a sterilized towel drawn tightly over the ear and scalp, a
portion of the towel being afterwards cut away so as to expose only the
field of operation. The patient should be in the recumbent position, the
head resting on some hard substance, such as a partially-filled
sand-bag, and turned over to the opposite side, so that the affected ear
is uppermost.
In addition to the ordinary instruments, those specially required for
this operation are a well-balanced mallet and several gouges and chisels
of varying size, one or two sharp spoons, a seeker, and a malleable
blunt-pointed silver probe. They should be sterilized in the ordinary
manner.
[Illustration: FIG. 216. DIAGRAM SHOWING POSITION OF SKIN INCISIONS IN
POST-AURAL OPERATIONS. 1, For removal of foreign bodies or exostoses, or
for excision of a stricture within auditory canal; 2, Usual incision for
the mastoid operation; 3, Prolongation of incision upwards for exposure
of temporo-sphenoidal lobe; 4, Extension of incision backwards, for
exposure of lateral sinus or cerebellum.]
_The incision._ The surgeon stands at the side to be operated upon,
facing the patient’s head. The auricle is pulled forward. An incision is
made through the skin, beginning just above the pinna, and is carried
downwards in a curved direction towards the tip of the mastoid process,
lying about half an inch behind the insertion of the auricle (Fig. 216).
Before making the incision, the tip of the mastoid process should be
determined. Care must be taken not to let the knife slip at the end of
the incision and so incise the neck tissues. The line of incision should
correspond to what will afterwards be the middle of the wound cavity in
the bone. If the incision be made too far forwards or too far backwards,
one of the edges of the skin incision may afterwards tend to overlap the
opening in the bone and in this way hinder the dressing and perhaps lead
to the formation of a sinus. If there be much thickening of the soft
tissues and periosteum, it may be necessary to make the incision longer
than usual in order to expose the field of operation sufficiently.
In the upper angle of the incision the temporal fascia and the
underlying temporal muscle will be exposed. Except in very muscular
subjects, in whom the muscle comes low down into the wound and has to be
cut through, it is better to push the lower border of the muscle upwards
by means of a periosteal elevator. The incision is now carried right
down to the bone throughout its length.
If there be an abscess over the mastoid process, its purulent contents
should be allowed to drain away, the abscess cavity being then irrigated
with a weak solution of biniodide of mercury (see p. 389).
[Illustration: FIG. 217. SCHWARTZE’S OPERATION. Showing field of
operation with anatomical landmarks and gouge in position for opening of
antrum.
A, Zygomatic ridge; B, Spine of Henle: behind and above it is the
suprameatal triangle; C, Fibrous portion of cartilaginous meatus, not
separated from bony. (In this and the following diagrams the gouge or
chisel is drawn small. In actual practice they may be much larger.)
]
_Exposure of the field of operation._ The periosteum and overlying soft
tissues are then reflected forwards and backwards with a rugine, until
the following points are brought into view: namely, the upper posterior
margin of the bony meatus (taking care not to separate the fibrous from
the bony portion of the meatus) and Henle’s spine in front, the
zygomatic ridge above, and the fibres of the sterno-mastoid muscle below
(Fig. 217). The tip of the mastoid process should just be seen. To do
this it may be necessary to cut away some of the fibres of the
sterno-mastoid muscle.
If the surgeon has two assistants, the duty of one of them is to hold
apart the edges of the wound by means of retractors, whilst the other is
employed in keeping the wound dry. If there be only one assistant, the
edges of the wound may be held apart by metal retractors.
Careful examination of the field of operation should now be made. There
may be no external signs of disease. As a rule, however, as a result of
the inflammatory process having already extended to the surface, the
periosteum is found to be much thickened, with extreme vascularity of
the underlying bone, or there may be a subperiosteal mastoid abscess of
varying size.
Excepting in infants, in whom pus may escape through the squamo-mastoid
suture, a subperiosteal abscess is always secondary to a fistula in the
bone, which is usually situated over the body of the mastoid process
just behind the suprameatal triangle. It may, however, occupy some other
position.
In the case of Bezold’s mastoid abscess (see p. 389), although no
fistula may be seen on the surface of the bone, pus may be found to well
up from beneath the mastoid process on cutting through the fibres of the
sterno-mastoid muscle. In other cases there may be actual necrosis of
the bone, as a rule involving the lower margin of the squamous portion
of the temporal bone (see p. 390).
The method of opening the antrum in a straightforward case will first be
described.
_Opening the antrum._ The approximate surface marking of the antrum is
the suprameatal triangle and the region just behind it, which, however,
as has been mentioned, is an uncertain guide. It is wiser, therefore, in
all cases of operation on the mastoid process to assume that the case is
one in which the lateral sinus extends far forward and is superficial,
and that the middle intracranial fossa is low lying.
The area of bone to be removed depends on the age of the patient; in the
adult it is about half an inch square, having as its boundaries the
zygomatic ridge above and Henle’s spine in front.
The bone should be removed by short decided taps of the mallet on the
gouge or chisel, held in contact with the bone in a sloping direction
(Fig. 217). This precaution is specially indicated whilst in the act of
removing the bone from above downwards and from behind forwards, in
order to prevent injury to the middle fossa, which may be low lying, or
the lateral sinus, which may project abnormally far forward (Fig. 218).
To permit of better control over the instrument, the hand holding it may
rest lightly against the patient’s head, which is now covered with a
sterilized towel. This control should always be sufficient to prevent
the chisel or gouge being driven unexpectedly too far inwards, an
accident which may easily happen if, by chance, there is a sudden
diminished resistance to the stroke owing to unexpected softening of the
bone or the inadvertent exposure of the dura mater. It is this
accidental slipping of the instrument which is often responsible for
injury to the lateral sinus or the facial nerve. With regard to choice
of instruments, I prefer the gouge, as it is safer than the chisel,
owing to it having rounded edges.
On removal of the superficial part of the cortex, the mastoid process
may be found to be sclerosed, or to consist of small or large cells
filled with granulations or purulent secretion.
(_a_) _If the bone be sclerosed._ The operation may be extremely
difficult, as the antrum is frequently of small size and very deeply
placed. As the tympanic cavity must not be interfered with, it is not
permissible to insert the seeker along the auditory canal into the attic
in order to determine the position of the aditus. The only guides,
therefore, are the anatomical landmarks.
The best method is to chisel away the bone close to and parallel to the
upper posterior margin of the external meatus. In chiselling along the
upper wall of the opening, the gouge, instead of being directed
downwards, as was the case in removal of the outer portion of the
cortex, is now directed inwards and at the same time slightly upwards
and forwards. In enlarging the lower part of the opening, the bone is
chiselled away obliquely inwards and upwards. The strokes of the gouge
are made alternately from above and below, so that gradually a
funnel-shaped opening is formed, having its point directed towards the
aditus.
[Illustration: FIG. 218. SCHWARTZE’S OPERATION. Showing exposure of the
antrum. Note sloping position of gouge in removal of bone in region of
lateral sinus.]
Anteriorly, the bone is removed as close to the posterior wall of the
auditory canal as possible, including the suprameatal spine. Above, the
line of chiselling must not extend beyond the zygomatic ridge, whilst
below sufficient bone should be removed towards the tip of the mastoid
process to permit of inspection of the deeper parts of the wound.
From time to time the operator makes use of the _seeker_ (Fig. 219).
This is a blunt-pointed probe whose tip is bent at right angles to its
shaft. With it any opening is probed carefully to see whether it is
merely a mastoid cell, or dura mater covering the outer wall of the
lateral sinus, or the middle cranial fossa, or if indeed it is the
antrum itself. The chief mistake is to work too low down. If the antrum
be small it may be missed, and the bone may be chiselled away too
deeply in endeavouring to discover it and the facial nerve or the
external semicircular canal injured. It is wiser, therefore, to work
high even if the dura mater of the middle fossa is exposed by doing so.
This should not lead to any harmful result provided the dura mater is
not injured.
As soon as the antrum is reached, pus will be seen to ooze through the
opening made, especially if it is under tension. The probe or seeker can
now be passed into a cavity of varying size. The antrum is recognized by
its smooth surface, which has quite a different appearance to that of
the mastoid cells.
[Illustration: FIG. 219. SCHWARTZE’S SEEKER.]
(_b_) _If the mastoid be not sclerosed._ The pathological condition
found on removal of the superficial cortical layer depends on the
anatomical structure and on the extent and virulence of the inflammatory
process. Only a few cells may be involved, or on the other hand the
whole mastoid process, if it be of the pneumatic type, may be converted
into a mere shell of bone, forming a large cavity filled with masses of
septic granulation tissue, carious bone, and pus. Sometimes, indeed,
owing to the tegmen tympani or bony wall of the sigmoid sinus being
already destroyed, the dura mater above or the lateral sinus posteriorly
may be found already exposed within the cavity. If this is the case the
pus may pulsate if present in large quantity. Any patches of soft
carious bone or granulation tissue should be removed with the curette.
If the disease be limited to a few superficial mastoid cells, it is
sufficient, according to those who do not always explore the antrum, to
expose and curette the cavity freely and to do nothing further. This,
however, should only be done if the bone surrounding the abscess cavity
is hard and apparently normal, and if there is no tract of granulations
leading from it in any direction. If an opening be found leading
directly into the antrum, it should be enlarged with the curette or
gouge. The extent of the antrum is next defined with the seeker, any
overlapping ledges of bone being removed by the gouge until the whole of
its inner surface is exposed.
The region of the aditus is now inspected under good illumination, using
a head-light if necessary. It is recognized as a small opening at the
anterior inner part of the antrum, on the floor of which may be seen the
posterior border of the external semicircular canal, standing out as a
whitish rounded eminence. Bone may be removed from its upper inner
margins, but the lower portion should not be interfered with for fear of
injuring or displacing the incus. To confirm the opening into the
aditus, a blunt-pointed curved probe may be passed for a short distance
through the aditus into the attic (Fig. 220).
With the curette all granulations should be removed.
_Treatment of the mastoid process._ The question now arises as to how
much bone to remove. This depends on the condition found; the chief
point is to make certain of removing all the infected cells.
In the case of marked sclerosis, the opening need not be large because,
if the bone between the cortex and the antrum be solid, it is hardly
probable that infection can spread through it to any outlying cells in
the tip of the mastoid or elsewhere.
[Illustration: FIG. 220. SCHWARTZE’S OPERATION COMPLETED. The seeker is
being passed through the aditus into the attic. Note the posterior
border of the external semicircular canal which forms the inner and
lower margin of the aditus.]
In the diploic and pneumatic varieties, the seeker must be used
constantly in order to discover any outlying cells, which are then
opened freely. If this be done systematically, infected cells may be
found some distance away from the antrum itself, although an area of
apparently healthy bone lies between them and the antrum. It must not be
forgotten that cells may extend posteriorly as far as the occipital
bone, or anteriorly along the zygomatic process, or even into the upper
posterior part of the auditory canal itself (see p. 374). If such
infected cells be not discovered, healing will be prevented.
However small or large the opening may be, all rough corners must be
removed, so that at the end of the operation a smooth funnel-shaped
cavity exists. To obtain this _a burr_ may be used, worked either by the
electric motor or, if a portable one, by an assistant. The burrs are of
various sizes and of the cross-cut variety recommended by Ballance. Some
operators perform the operation by burring throughout. Personally,
during the earlier stages of the operation, I prefer to use the gouge
and mallet. If the operator has not had much experience in the use of
the burr there is always a slight risk, if it be not kept sufficiently
under control, and especially if too great pressure be used, of it being
driven through the dura mater above or into the lateral sinus
posteriorly, or of it injuring the contents of the tympanic cavity. As a
means of finishing the operation no instrument could be better. In
private practice, however, few surgeons keep one. For this reason it is
advisable to become accustomed to the chisel and gouge.
_Removal of part of the posterior wall of the auditory canal._ This may
be necessary if the anterior wall of the antrum and mastoid process be
affected. The fibrous portion of the auditory canal is partially
separated from the bony portion and held forward by means of a
retractor. The upper posterior portion of the bony meatus can now be
removed either by means of punch-forceps or by the chisel, to what
extent does not matter so long as its innermost portion, ‘the bridge,’
is not interfered with, that is, so long as the tympanic cavity and
aditus are not encroached upon.
_Exposure of the dura mater and lateral sinus._ This may have already
occurred before the operation, as a result of extension of the bone
disease, or it may be necessary to do so during the course of the
operation. Owing to the fact that an extra-dural abscess is a frequent
complication of acute inflammation of the mastoid process, Victor
Horsley and Körner advocate the exposure of the dura mater and the
lateral sinus in every case, especially if a tract of carious bone leads
in their direction. No harm is done in exposing these structures, and it
precludes missing an extra-dural abscess.
It is better to expose the dura mater than to leave it covered with
infected bone and septic granulations.
_Final step of the operation._ In order to make certain that a free
opening exists between the antrum and the tympanic cavity, some warm
boric lotion should be syringed through the opening of the aditus. A
small syringe is used, having a fine piece of india-rubber tubing fixed
on to its point. The end of the tubing is pushed into the entrance of
the aditus. The fluid is then syringed through and should emerge from
the external meatus. This is also beneficial in order to cleanse the
tympanic cavity of its purulent secretion. To expel all the fluid from
the middle ear the syringe is emptied and the piston withdrawn to its
full extent. Its point is again placed within the entrance of the aditus
and the piston pressed home, so that air is forced through and so drives
out any remaining fluid from the tympanic cavity into the external
meatus, which in its turn should be carefully dried. If there be no
perforation, or if it be very small, the membrane should be freely
incised before fluid is syringed through the aditus.
_Immediate treatment of the wound cavity._ The wound cavity is lightly
packed with sterilized ribbon gauze, half an inch in width. Care must be
taken to introduce the gauze right down to the aditus and to pack the
cavity evenly.
The wound should be left open for a few days until the acute
inflammation of the soft tissues has subsided, after which the upper and
lower angles of the wound can be partially closed by sutures. A strip of
gauze is also inserted into the auditory canal and a light dressing of
plain sterilized gauze and a pad of cotton-wool covers the ear and
surrounding parts. The bandage should be passed round the head and not
beneath the chin, as the latter method is often a source of great
discomfort to the patient during the stage of vomiting following the
anæsthetic.
Blake of America has suggested that the wound should be allowed to fill
with blood-clot on the supposition that the subsequent organization of
the clot will result in a rapid closure of the wound. This method cannot
be considered seriously owing to the impossibility of keeping the wound
sterile.
=After-treatment.= There is seldom any shock, but there may be
considerable pain during the next twenty-four hours.
If there has been no subperiosteal abscess, the dressing need not be
removed for forty-eight hours. If an abscess has been present the dry
dressing should be removed after twenty-four hours, and if there is much
œdema and inflammation of the surrounding region, a compress of wet
boric lint, kept in position by a few turns of a bandage, should be
substituted, and changed every four hours.
Drainage tubes should be shortened and removed as soon as possible. The
gauze within the wound cavity should be changed every second day, or
daily if there be much secretion. If there be much discharge and the
condition be very septic, an ear-bath of hydrogen peroxide may be given
at each dressing and the cavity syringed out with a weak solution of
biniodide of mercury; otherwise it is sufficient to use boric acid
lotion.
If the operation has been successful, the purulent discharge from the
tympanic cavity rapidly diminishes, frequently ceasing before the third
day. The auditory canal is then firmly packed with gauze, especially in
its outer part, in order to prevent stenosis of its lumen, which is
liable to occur if the posterior fibrous portion of the canal has been
separated from the bony meatus during the operation. Granulations very
quickly block the aditus and so separate the antrum and mastoid cavity
from the tympanic cavity. The wound can now be treated as an ordinary
deep surgical wound, care being taken that it is packed from the bottom
at each dressing.
If all the diseased bone has been removed, smooth healthy granulations
will cover the wound. The continuance of pus from any spot, or the
local growth of exuberant granulations, suggest the presence of an
infected cell or a fragment of carious bone. Under cocaine anæsthesia,
the part should be inspected carefully, and, if necessary, curetted
freely. In other cases the local application of chromic or
trichloracetic acid is sufficient.
After the second week the wound becomes shallower, actual healing of the
wound depending on the size of the cavity.
Unless a very large amount of bone had to be removed, the resulting
deformity is not great and usually only consists of slight sinking in of
the skin. In some cases the final result is only a fine scar, which can
generally be concealed by the hair.
The difficulties and dangers of the operation are considered in the next
chapter (see p. 412).
=Results.= 1. If the operation has been successful (and this is usually
the case), pyrexia and pain rapidly disappear, the patient experiencing
remarkable relief from the head symptoms, so that within twenty-four
hours he feels almost well. Healing of the wound is usually complete
within six weeks, and before this date the hearing power will probably
have been restored to normal.
2. The operation may not have been successful and the following
unfavourable symptoms may occur:--
(_a_) The pyrexia may continue irregularly for a few days. If there be
no other symptoms, this is probably due to septic absorption from the
wound and need not cause very great alarm. If accompanied by pain, it
may either mean that all the infected mastoid cells have not been
opened, or suggest the onset of osteomyelitis of the temporal bone. If,
in addition, such symptoms as rigors, delirium, optic neuritis,
headaches, or vomiting occur, they indicate some intracranial
complication.
In cases of doubt it is wiser to explore the wound under a general
anæsthetic and then to determine what operation will be necessary.
(_b_) The general condition of the patient may be excellent, but
otorrhœa or a fistula over the mastoid process may persist. Continuance
of otorrhœa, in spite of healing of the wound posteriorly, means that
although the disease involving the mastoid process has been eradicated,
yet the walls of the tympanic cavity are themselves involved. This will
probably necessitate the subsequent performance of the complete mastoid
operation.
On the other hand, the suppuration may cease from the middle ear with
complete recovery of hearing, and yet a fistula of the mastoid may
remain. This means that all the diseased bone has not been removed. This
should now be done.
TREATMENT OF SPECIAL CONDITIONS
=In an infant.= In an infant under two years of age the incision should
be somewhat higher than usual. In making it, too much pressure should
not be used, as the bone is frequently thin at this age, and if carious
it may be so soft that the knife may possibly enter the intracranial
cavity. In exposing the area of operation, it must be remembered that
the posterior root of the zygoma and the antrum lie at a much higher
level than in the adult. The opening into the antrum, therefore, is made
almost above rather than behind the margin of the auditory canal. In
these cases a fistula is usually present, and the bone is so soft that
it can generally be removed by means of a sharp spoon or curette. At the
same time, however, the aditus should be exposed and the opening made
funnel-shaped in order to allow of proper dressing.
=Subperiosteal abscess.= The treatment depends on the extent of the
abscess. If it be small, the lining membrane may be dissected away, the
wound being afterwards treated in the ordinary manner. If the abscess
cavity extends upwards towards the parietal region, or forwards along
the temporal fossa, then drainage tubes should be inserted, their ends
being brought out into the mastoid wound. It is rarely necessary to make
counter-incisions. The completion of the operation is seldom difficult,
as the fistula actually leads into the antrum. If the fistula be a large
one and the bone is carious a sharp spoon may be used; otherwise a gouge
is necessary.
=Bezold’s mastoid abscess.= If the lower portion of the mastoid process
be composed of large cells, the abscess within the mastoid may break
through the bone at its inner surface in the region of the digastric
fossa. In consequence of this the pus may infiltrate the neck tissues
beneath the fascia of the sterno-mastoid muscle and form a large abscess
recognized clinically as a hard and painful swelling situated below the
mastoid process instead of over it. This condition was first described
by Bezold.
After exposing the antrum in the ordinary way, the tip of the mastoid
process is opened freely. It is usually found to contain large cells
filled with pus. Any granulation tissue is curetted away and the cavity
dried. The inner surface of the bone is then inspected carefully in
order to find the opening, which usually leads into the digastric fossa.
The margins of the fistula should be curetted freely and the opening
enlarged, if necessary. If the deep-lying cervical abscess be large, the
finger may be passed into the abscess cavity behind the mastoid process,
between it and the cut fibres of the sterno-mastoid muscle. In this way
the limits of the cavity can be made out, and any septa forming pockets
within it can be broken down. A counter-incision should be made through
the tissues of the neck at the lower limit of the abscess. The opening
should be sufficiently large to permit the insertion of a large drainage
tube into the cavity. If the abscess be small it may not be necessary to
make a counter-opening, but merely to insert a drainage tube into it,
passing it from above downwards along the passage made by the finger.
=Necrosis.= In children necrosis of the temporal bone is not uncommon,
especially if the middle-ear suppuration occurs in the course of a
specific fever or is the result of tuberculous infection.
The part usually affected is the lower margin of the squamous portion of
the temporal bone and the tympanic ring. Sometimes, however, the
necrosis is very extensive, involving a large area of the petrous bone,
including the labyrinth. These cases are always grave, and if a fatal
result occurs it is usually in consequence of meningitis.
In adults necrosis is rare excepting as a localized patch usually
situated superficially in the cortex of the mastoid process. Partial
necrosis of the labyrinth, more especially of the vestibule and the
portions of the semicircular canals, is also met with occasionally. When
the necrosed area is superficial, such as the squamous portion of the
temporal bone or the cortex of the mastoid process, it should be
removed. If, however, it be situated more deeply, forcible removal
should not be attempted until the sequestrum becomes loose, the wound
cavity being meanwhile kept as aseptic as possible.
=Osteomyelitis.= In children, as the result of acute inflammation of the
mastoid process, the bone may be found riddled with small points of pus,
sometimes termed osteomyelitis. As a result of free opening of the
mastoid cavity recovery, as a rule, takes place in the ordinary manner.
Distinct from this is another condition in which thrombosis of the
diploic veins occurs. It is, fortunately, a rare complication of mastoid
disease. It may occur before operation or be the result of infection of
the bone as a result of operation. The infection tends to spread in
every direction, more especially upwards along the parietal region and
towards the occiput. With this, localized areas of necrosis or abscesses
may occur, giving rise to painful swellings on the head, and usually are
accompanied by cellulitis of the scalp, pyrexia, and intense headaches.
The only chance of recovery is to expose the affected area freely, and
thoroughly remove all the diseased bone. To do this it may be necessary
to lay bare the dura mater over a considerable area. If, however, the
disease be not quickly eradicated, death will eventually occur as a
result of extension of the septic infection to the larger veins, or from
some other intracranial complication.
CHAPTER VI
THE COMPLETE MASTOID OPERATION
Before considering the question of the radical operation, it is assumed
that conservative treatment has been attempted and has failed, and that
the middle-ear suppuration has existed for a considerable period.
=Indications.= (i) As a prophylactic measure. If there be merely a
perforation of the tympanic membrane and no evidence of disease of the
ossicles nor the walls of the tympanic cavity, the probability is that
the continuance of the suppuration is due to an affection of the mucous
membrane rather than of the underlying bone; for example, to a chronic
empyema of a large antrum cavity which, owing to its anatomical
structure, will not drain freely.
In such cases the complete mastoid operation is only indicated if the
deafness is extreme, the bone conduction diminished, and the high
tuning-forks not well heard, or if the ossicles are bound down by
adhesions to the inner wall of the tympanic cavity, as it is then
obvious that the hearing power cannot be restored completely.
It must, however, be remembered that in many cases a slight discharge
may exist for years without giving rise to any complications. If the
patient be made aware of the slight danger which exists in every case of
middle-ear suppuration, and be in a position to obtain medical attention
if retention of pus occurs, then operative measures may be deferred
indefinitely. If, on the other hand, the patient intends going to some
remote country where medical attendance is impossible, then it is
probably wiser to submit to the complete operation rather than risk
future trouble.
(ii) If there be recurrent attacks of giddiness, nausea, or headaches
radiating up the affected side which are not arrested by the ordinary
methods of treatment. These symptoms of retention of pus within the
antrum and mastoid process should be considered as danger signals. In
this case also it is assumed that the hearing cannot be restored, and in
consequence there is no object in performing Schwartze’s operation.
(iii) If there be recurrence of polypi and granulations within the
tympanic cavity in spite of curetting, especially if the operation of
ossiculectomy has already been performed.
(iv) If there be symptoms of retention of pus due to want of free
drainage in the case of stenosis of the external meatus, whether due to
fibrous contraction of its soft parts, or from the presence of
exostoses.
(v) If cholesteatomatous formation be present. Even if there be no
symptoms necessitating immediate interference, operation is usually
indicated owing to the fact that cholesteatoma is the commonest
predisposing cause of intracranial suppuration and septic thrombosis of
the lateral sinus.
(vi) If there be a fistula of the bony wall of the mastoid process,
whether it extends anteriorly into the auditory canal or externally
through the skin over the region of the mastoid process. It must not be
forgotten, however, that simple opening of the antrum and mastoid cells
will be quite sufficient if the condition is the result of a recent and
acute inflammation of the mastoid process.
(vii) If there be facial paralysis occurring in the course of a chronic
middle-ear suppuration. This may mean either that there is bone disease
involving the facial canal, or that the inflammatory process has spread
through the Fallopian canal towards the inner ear. In either case
operation is indicated.
(viii) As a preliminary step in intracranial suppurative lesions of
otitic origin.
(ix) In tuberculosis of the middle ear. If the patient’s general
condition permits of it, and if the pulmonary disease be slight or
arrested, the complete operation should always be done. The difficulty
is to remove all the diseased bone. If this can be done the wound will
heal quite well.
(x) In acute inflammation of the mastoid process occurring in the course
of chronic middle-ear suppuration, the complete mastoid operation should
be performed, as in these cases the attic, aditus, and antrum are always
involved.
(xi) Amongst the rarer conditions for which the complete operation may
be necessary are removal of a foreign body which has been pushed
inadvertently into the region of the attic and aditus and cannot
otherwise be removed; and actinomycosis of the temporal bone.
METHODS OF OPERATION
The actual method of carrying out this operation varies. For those who
have not had great experience the best method is first to open the
antrum, as in Schwartze’s operation, and then to remove the ‘bridge’ of
bone between it and the tympanic cavity (Küster-Bergmann operation,
sometimes called the Schwartze-Stacke operation). Instead of doing this,
the upper posterior part of the auditory canal may be chiselled away
simultaneously during the act of exposing the antrum (Wolf’s operation).
On the other hand, the mastoid and antrum may be exposed from within
outwards by removing the outer attic wall and working backwards
(Stacke’s operation).
=The Küster-Bergmann (or Schwartze-Stacke) operation.= The preliminary
preparation, the position of the patient, and the instruments required
are the same as in opening the antrum.
[Illustration: FIG. 221. THE ‘RADICAL’ MASTOID OPERATION. To show
removal of the ‘bridge’ from above. The seeker, inserted into the
aditus, acts as a protector to the underlying external semicircular
canal and facial nerve.]
The =incision= is begun just above the upper insertion of the pinna, and
is carried downwards in a curved direction behind the auricle along the
margin of the skin and scalp. Some authorities prefer to make the
incision close behind or even along the post-auricular fold. In favour
of the incision being placed far back is the concealment of the scar by
the hair. Also, as it is situated on healthy bone somewhat posterior to
the actual wound cavity, it should heal by primary union and with no
after-displacement of the auricle. In addition, if it be necessary to
expose the lateral sinus, this can usually be done by simple retraction
of the soft parts.
The exposure of the field of operation is the same as in the simple
opening of the antrum, excepting that the soft tissues should be
separated a little further forwards and above the external bony meatus,
as in this operation the upper posterior wall has to be removed.
The antrum is opened as already described (see p. 382).
The fibrous portion of the external meatus is separated carefully from
the posterior wall of the bony meatus by means of a periosteal elevator,
and is pulled forward by a retractor. The external portion of the
posterior wall is now removed in a wedge-shaped fashion by alternate
strokes of the chisel from above downwards (Fig. 221) and from below
upwards. The upper level of the bone to be removed corresponds with the
zygomatic ridge. After a small portion has been removed, a pair of
forceps is passed into the auditory meatus and its point made to
project into the wound posteriorly through the end of the now detached
fibrous portion of the auditory canal. With the forceps a piece of gauze
is drawn through the auditory meatus in the form of a loop. By its means
the auricle and fibrous portion are pulled well forward, thus exposing
to view the tympanic cavity. Two openings are now seen: one, the
auditory canal and tympanic cavity, in front, and the other, the antrum
and mastoid cavity, behind. Between them is the ‘bridge’; that is, the
innermost portion of the posterior wall of the auditory canal.
[Illustration: FIG. 222. STACKE’S PROTECTOR.]
Any granulations present are curetted away gently from the tympanic
cavity. The seeker is next passed into the tympanic cavity, and its
point directed upwards and backwards into the aditus, so that it rests
on the floor of the latter, or its point may be inserted into the aditus
through the mastoid wound. Beneath it lies the eminence of the external
semicircular canal and the facial nerve. This is a most important
landmark. Provided the seeker is kept in this position, all the bone
lying superficially to it can be removed without injury to the
semicircular canal or facial nerve.
In this connexion may be mentioned Stacke’s probe or ‘protector’ (Fig.
222). Although historically an instrument of importance, I do not make
use of it. It is so large and of such sharp outline that, unless used
with extreme care, it is itself very liable to injure the facial nerve.
For this reason I prefer the seeker, a much finer and more delicate
instrument, which will serve the purpose without the same risk (Fig.
219).
The ‘bridge’ is now carefully removed by the gouge or chisel, frequent
use being made of the seeker meanwhile. As the roof of the antrum,
aditus, and attic is a continuous one, the bone to be removed is
necessarily at a higher level than the roof of the bony meatus. This is
a point which must not be forgotten, as the great fault of the beginner
is to remove the bone too low down.
As the aditus is approached, the strokes of the chisel must be very
gentle. If too much force be used, the chisel, on breaking through the
innermost portion of the ‘bridge’, may injure the deeper-lying parts,
more especially the facial nerve.
Some authorities advocate removal of the ‘bridge’ by means of bone
forceps. This, however, is not so sure a method as by the chisel or
gouge.
After removal of the bridge, the tympanic cavity, antrum, and mastoid
will form a continuous cavity. As a rule the outline of the external
semicircular canal appears as a well-marked white eminence, and
projecting beyond it are the remains of the posterior wall of the
auditory canal. In removing this ridge good illumination is essential.
The bone is removed in layers with the chisel, beginning at the tip of
the mastoid process, and working parallel to the auditory canal and the
underlying facial canal. If necessary the seeker may be used as a guide,
its point being allowed to rest on the floor of the aditus, superficial
to the semicircular canal (Fig. 223).
The amount of bone removed should be such that at the end of the
operation the auditory canal is only separated from the main cavity of
the mastoid antrum by a slight eminence, the remainder of the posterior
wall, which is continuous with that of the external semicircular canal.
[Illustration: FIG. 223. THE ‘RADICAL’ MASTOID OPERATION. Showing
removal of the remains of posterior wall of the auditory canal; the
seeker acting as a protector.]
Occasionally the facial canal and the stylo-mastoid canal are abnormally
superficial. Provided the bone be removed in the manner just described,
the facial nerve should not be injured, even though it may be exposed
inadvertently. A warning of this occurrence is given by bleeding from
the vessels within the canal (see p. 374).
If the malleus and incus be still _in situ_, they can now be seen and
can usually be removed by the curette. No force must be used. Removal of
the incus is a matter of no difficulty. In the case of the malleus there
may be some resistance owing to the attachment of the tendon of the
tensor tympani muscle. If so, the malleus should be grasped by a fine
pair of forceps and the tendon severed by means of Schwartze’s tenotomy
knife.
The overhanging edge of the outer wall of the attic can now be felt by
means of the seeker. It is best removed by gentle taps of the chisel or
small gouge. Especial care must be taken not to drive the gouge too far
inwards. If this be done inadvertently, the transverse portion of the
facial nerve passing along the inner wall of the tympanic cavity may be
injured. As a safeguard some surgeons use an attic punch-forceps or a
burr, others a Stacke’s protector which should be inserted into the
attic before chiselling away its outer wall.
After the outer attic wall has been removed, the roof of the auditory
canal and the attic should be continuous. This is verified by inserting
the seeker, with its point turned upwards, within the attic, and then
withdrawing it; no ridge of bone should now prevent its withdrawal.
[Illustration: FIG. 224. PFAU’S CURETTE FOR THE EUSTACHIAN TUBE.]
Granulations or the epithelial lining of cholesteatomata should be
removed from the recesses of the tympanic cavity with a small curette.
Care must be taken not to injure the surface of the promontory, or the
region of the fenestra ovalis and fenestra rotunda. It is especially
important to curette away the mucous membrane from the orifice of the
Eustachian tube in order that scar tissue may obliterate its lumen and
so prevent reinfection of the middle ear from the naso-pharynx. For this
purpose a narrow curette is necessary (Fig. 224).
Removal of the innermost portion of the floor of the auditory canal is
not always necessary. Sometimes, however, the ‘hypotympanum’ is well
marked, and in order to ensure a good result it is wiser to remove this
projecting piece of bone. If the ridge of bone be removed piecemeal, and
if the gouge or chisel be kept parallel to the floor of the canal, there
should be no danger of wounding the bulb of the jugular vein. Cases,
however, have been recorded in which this has occurred.
The final step is to see that no pockets nor overhanging ledges or
ridges of bone remain, and that all the diseased area has been removed.
The cavity, although irregular in outline, should be a continuous one
with a smooth surface (Fig. 225).
=Wolf’s operation.= This slight modification of the Küster-Bergmann
operation requires merely a note of description. The position of the
patient and the preliminary steps of the operation are the same as in
the former operation.
In this operation, instead of first exposing the antrum cavity and
afterwards removing the posterior wall of the external meatus, this
procedure is performed in one step.
The chisel or gouge is first brought into contact with the bone just
behind the upper posterior margin of the auditory canal. The bone is
removed in layers by chiselling it away in a forward direction and in
such a manner that each stroke of the chisel is carried directly into
the auditory canal (Fig. 226). With each successive stroke, begun a
little more posterior and inferior to the one preceding it, more bone is
removed until at length the antrum is exposed. There should be no risk
of injuring the external semicircular canal nor the facial nerve, owing
to the fact that the outer wall of the antrum lies superficial to the
tympanic cavity and aditus.
[Illustration: FIG. 225. THE ‘RADICAL’ MASTOID OPERATION COMPLETED. A,
Attic and antrum; B, External semicircular canal; C, Promontory and
inner wall of tympanic cavity; D, Remains of posterior wall of auditory
canal; E, Facial nerve canal; F, Floor of auditory canal.]
After the antrum has been exposed, the technique of the operation is the
same as that already described in the Schwartze and Küster-Bergmann
operation.
=Advantages.= 1. If the surgeon be experienced it saves much time, as
the preliminary steps of the operation can be carried out very rapidly.
2. If the mastoid be sclerosed and there are no landmarks, the antrum,
however small, is bound to be reached by making use of this method, by
keeping high up, and, if necessary, exposing the dura mater. To verify
the depth to which the bone may be removed and also the position of the
antrum, the seeker should be inserted occasionally through the tympanic
cavity into the aditus.
=Disadvantages.= If the surgeon be not experienced, it is not so safe a
method as that of first exposing the antrum.
=Stacke’s operation.= After exposure of the field of operation, as in
the Küster-Bergmann operation, the fibrous portion of the auditory canal
is separated posteriorly from the bony portion.
[Illustration: FIG. 226. WOLF’S OPERATION.]
Any granulations, together with the malleus and incus, are removed from
the tympanic cavity (see p. 353). Under a good illumination, using a
head-lamp if necessary, the surgeon passes a seeker along the auditory
canal, its point being made to project into the attic in order to define
its limits and that of the aditus. The innermost portion of the upper
posterior wall of the auditory canal, that is, the outer wall of the
attic, is now removed piecemeal by means of a small gouge (Fig. 227). By
working backwards the aditus is approached, the bone being removed
carefully in small fragments. The seeker is inserted repeatedly into the
entrance of the aditus so as to rest on the external semicircular canal,
in order that the position of the latter and the underlying facial nerve
may be kept constantly in mind. More bone above and external to this
point is removed in small fragments, until at length the upper and
innermost portion of the antral wall is removed and its cavity thus
exposed. The cavity is gradually enlarged by removing still more bone in
a backward and outward direction, until finally it resembles that left
after the complete operation. Stacke originally devised this method in
those cases in which he considered that the disease was limited to the
ossicles, the walls of the attic, aditus, and innermost portion of the
antrum. It was, indeed, merely a more radical method of performing
ossiculectomy.
=Advantages.= Although this operation has practically been abandoned as
a method of performing ossiculectomy, yet under the following conditions
it may be adopted during the performance of the complete operation:--
1. If the mastoid be very sclerosed and if the antrum cannot be
exposed, although the bone has been removed to a depth corresponding to
its usual position.
2. If there be difficulty in exposing the antrum in the performance of
the radical operation owing to the lateral sinus projecting far forwards
and the middle intracranial fossa overlapping it externally.
=Disadvantages.= The chief disadvantage is that it is more difficult and
tedious to begin the operation within the depth of the wound, and if the
meatus is very deep and narrow it may be almost impossible to carry out.
=Preservation of the ossicles and tympanic membrane after performing the
complete mastoid operation.=
This method of operation is well known and has been performed for some
years, especially by Jansen of Berlin, and in America.
[Illustration: FIG. 227. STACKE’S OPERATION.]
The only indication for this modification of the complete mastoid
operation is disease involving the antrum and mastoid process so
extensively as to require complete removal of the posterior wall of the
auditory canal, without there being any coexisting bone disease of the
walls of the attic or of the ossicles.
As the complete mastoid operation is only performed for some condition
due to chronic middle-ear suppuration, it is difficult to imagine that
the ossicles and attic region could remain unaffected when the extent of
the disease necessitates the complete operation.
In my opinion, if it be necessary to remove the ‘bridge’ it is also
necessary to remove the outer wall of the attic and with this the
malleus and incus. If, on the other hand, there be no bone disease of
the attic region or of the ossicles, Schwartze’s operation, or some
modification of it, should be sufficient. The majority of aurists agree
that, excepting in those cases in which the continuance of the
suppuration is due to an empyema of the antral cavity, the ossicles are
almost invariably carious to a greater or lesser extent in chronic
middle-ear suppuration. This view is supported by Grunert’s researches
(_Archiv für Ohrenheilkunde_, Band 40), who found that the ossicles were
only normal in five cases in a series of 113 cases in which the complete
operation had been performed.
[Illustration: FIG. 228. POST-MEATAL SKIN FLAPS (_Author’s method_).
Bistoury incising the posterior fibrous portion of the auditory canal.
The dotted line shows the line of incision. A is the Y-shaped flap
afterwards sutured to the skin behind the auricle.]
Although removal of the ‘bridge’ may eradicate the disease within the
mastoid process and antrum, yet, if the ossicles are left,
post-suppurative adhesions will almost certainly afterwards bind them
down and so cause a greater deafness than if they had been removed
originally. Still, a few isolated cases have been reported in which
hearing to the extent of 20 feet or more has been obtained as the result
of this operation. The same results, however, frequently occur after the
performance of the complete operation with removal of the malleus and
incus. Until we have a large and consecutive series, recording the
results of this particular operation in detail, together with
information regarding the duration of the symptoms, the previous
treatment, and the condition of the ear before operation, it is
impossible to judge the value of this method.
THE FORMATION OF POST-MEATAL SKIN FLAPS
This is done for two reasons: firstly, to prevent stenosis of the
auditory canal; and secondly, to aid the growth of the epithelium over
the wound surface, so that the latter will heal as rapidly as possible.
These flaps may be formed in several different ways. The following is
the technique I adopt: A long, narrow, curved bistoury is passed down
the auditory meatus so that it projects through the detached end of the
fibrous portion, its point being directed backwards. The auricle is held
well forward and the fibrous portion of the meatus cut through
posteriorly, from within outwards, for a short distance (Fig. 228). The
edge of the bistoury is then directed in a slanting direction upwards
and outwards, and the incision continued as far as the cartilaginous
portion of the meatus, care being taken not to cut into the concha. The
bistoury is then withdrawn and reinserted at the point at which it was
first made to turn upwards. It is now directed downwards and outwards
and, in a similar manner, the incision is made in a slanting direction
towards the inferior margin of the cartilaginous meatus. In carrying out
these manipulations care must be taken that the outer portion of the
bistoury does not injure the tragus or other portion of the auricle, a
mistake which can easily occur. The fibrous portion of the meatus is
thus divided by a Y-shaped incision into three small flaps; namely, a
posterior or external V-shaped flap, and a superior and an inferior flap
(Fig. 229).
[Illustration: FIG. 229. POST-MEATAL SKIN FLAPS (_Author’s method_).
Flaps cut: A, Y-shaped flap sutured to the skin; _b_, Superior flap;
_c_, Inferior flap.]
The outer flap is fixed to the skin behind the auricle by means of a
catgut suture (Fig. 230), and the auricle is then pulled back into its
normal position. By inserting the tip of a finger into the meatus, the
upper and lower flaps are pressed upwards and downwards against the roof
and floor of the mastoid cavity, and can be kept in position afterwards
by suturing the flaps to the subcutaneous tissue or by packing the
cavity through the meatus with a strip of ribbon gauze.
Amongst other methods the following may be mentioned:--
=Körner’s method= (Fig. 231). Two parallel incisions are made in a
longitudinal direction through the fibrous portion of the posterior wall
of the meatus and are prolonged outwards as far as the concha. On the
auricle being restored to its normal position, this posterior flap is
pressed backwards and so covers a large area of the posterior wound
surface. The chief objection to it is that, owing to involvement of the
concha, there is considerable enlargement of the meatal opening and
therefore subsequent disfigurement.
[Illustration: FIG. 230. CLOSURE OF WOUND AFTER ‘RADICAL’ MASTOID
OPERATION. A is the point at which the Y-shaped meatal flap is sutured
to the skin.]
=Panse’s method= (Fig. 232). A transverse incision is carried through
the posterior margin of the meatus, at the junction of the concha and
auditory canal posteriorly. With a pair of scissors or knife, the
posterior wall of the fibrous portion of the canal is now split by a
longitudinal incision. In this way two flaps are formed, a superior and
inferior one. They are fixed into position by catgut sutures through the
subcutaneous tissues at the upper and lower angles of the wound.
=Stacke’s method= (Fig. 233). This consists of a large inferior flap,
formed by making a longitudinal incision along the posterior upper
border of the fibrous portion of the auditory canal and a transverse
incision meeting it at right angles, the latter cutting through the
fibrous portion of the meatus at its junction with the concha.
In order that these flaps may be thinner and more adaptable, the
subcutaneous tissue should be cut away. Of these flaps the Y-shaped one
is the most practicable, as it is suitable whether the posterior wound
is closed or left open.
[Illustration: FIG. 231. KÖRNER’S POST-MEATAL FLAP.]
[Illustration: FIG. 232. PANSE’S POST-MEATAL FLAP.]
[Illustration: FIG. 233. STACKE’S POST-MEATAL FLAP.]
Körner’s method has the objection that there is subsequent disfigurement
owing to the large meatal opening formed by cutting into the concha. It
has the advantage, however, that the large posterior flap will cover
the posterior surface of the wound cavity to a considerable extent, and
also that it will permit a good view of the surface.
Panse’s flap is only of service if the posterior wound is left open and
if there is not sufficient tissue left to make a posterior flap owing to
previous destruction of the posterior wall of the auditory canal.
Stacke’s method is good if skin-grafting is afterwards employed.
CLOSURE OF THE WOUND
Excepting under the conditions mentioned below, the posterior wound is
closed by bringing together the edges of the skin incision with fine
silkworm-gut sutures (Fig. 230). Before this is done, the wound cavity
should be irrigated with a weak solution of biniodide of mercury, dried,
and the deeper parts of the wound plugged with a strip of gauze inserted
through the external meatus. This will not only arrest the hæmorrhage
and keep the inner part of the wound dry, but at the same time will keep
the skin flaps in position. After the wound has been closed, firm
pressure should be applied in front and behind the ear to press out any
blood from the cavity.
As a final step the gauze which has been inserted into the meatus is
removed, and the cavity again packed evenly and lightly from the bottom
of the wound with a fresh strip. The ear and surrounding parts are
protected with a pad of sterilized gauze covered with cotton-wool and
kept in position with a bandage.
_The posterior wound should be left open under the following
circumstances_:--
1. If there be an abscess over the mastoid process. Although it may be
possible to excise the whole of the lining membrane of the abscess
cavity, it is wiser to leave the wound open for the first few days. The
innermost portion of the wound cavity is packed through the external
meatus, only the superficial part being packed through the posterior
wound incision. As healthy granulations appear, the posterior packing is
diminished, so that the edges of the incision gradually come together.
If necessary, the edges of the wound can also be freshened and brought
together by silkworm-gut sutures under cocaine anæsthesia.
2. If there be extensive disease of the bone, especially if the dura
mater and lateral sinus are covered with septic granulations.
3. If there be bone disease of the anterior and inferior parts of the
tympanic cavity. The after-treatment of packing or the curetting away of
granulations can be carried out more easily through the posterior wound
than through the external meatus, as it gives a better view of these
regions.
4. In young children it is frequently advisable to leave the posterior
wound open owing to the difficulty of packing the wound cavity through
the small external meatus.
SKIN-GRAFTING AFTER THE MASTOID OPERATION
In order to shorten the duration of healing, a large Thiersch’s skin
graft may be transplanted into the wound cavity. If this procedure be
adopted it may be carried out in several ways. The skin may be
transplanted in one large piece or in several small portions, and it may
be introduced into the wound cavity either immediately after the
completion of the mastoid operation or from seven to ten days later.
There is considerable diversity of opinion as to whether skin-grafting
should be employed or not, and also when it should be done.
This may be partially accounted for by the fact that although,
theoretically, the application of skin grafts is easy, yet, practically,
the technique is difficult. Those who favour skin-grafting point to the
fact that healing of the wound may take place within five weeks,
whereas, if grafting be not undertaken, cicatrization of the cavity,
even under favourable conditions, can hardly be expected to occur before
eight to twelve weeks.
The skin-grafting operation as suggested by Charles Ballance is
generally performed as a second stage, some ten or more days after the
primary operation. This, from the patient’s point of view, is a serious
matter; and the disappointment caused by the grafting not being always
successful has induced many to give it up and to be content with what
seems to be a more certain, though more prolonged, after-treatment.
More recently, however, it has been shown that in suitable cases skin
grafts, if applied at the time of the completion of the primary
operation, will take just as well as at a later date. This altogether
alters the aspect of the case. If at the end of the primary operation it
be certain that all the diseased bone has been removed and the cavity
has been rendered aseptic, there can be no objection to the immediate
application of skin grafts. If the result be successful, the period of
after-treatment is considerably curtailed. If, on the other hand, it be
not successful, the patient, beyond having a raw surface on his arm or
leg for a few days, is no worse off than if the graft had not been
applied.
Skin-grafting, however, cannot be done in every case. Two conditions are
necessary for its success: firstly, that all the diseased bone has been
removed; and secondly, that the wound cavity is aseptic.
Immediate skin-grafting, therefore, should not be employed if, in
addition to the chronic disease, there be acute inflammation of the
mastoid process, or of the subcutaneous tissues covering it; nor should
it be done if it has been necessary to expose the dura mater over a
large area, nor if there be any possibility of some subsequent
intracranial complication. In such cases it may be justifiable to do
skin-grafting after the acute symptoms have subsided. If, however, the
case be progressing satisfactorily, the advisability of submitting the
patient to a second operation should be a matter of careful
consideration.
Disease of the inner wall of the tympanic cavity, or around the orifice
of the Eustachian tube, is also a contra-indication against grafting, as
the graft, if applied, will not take over these areas. The author’s
opinion with regard to skin-grafting is that, if it can be applied
immediately after the completion of the primary operation (and the
conditions justifying this are limited), it may be done. If, however,
the conditions be such that they will not permit of this, it should not
be done at all.
=Technique.= _When the grafting is done at the completion of the mastoid
operation._ The first step is to see that the mastoid wound cavity is
rendered thoroughly aseptic and dry. All bleeding points in the soft
tissues are arrested by means of pressure forceps. The mastoid cavity is
then filled with hydrogen peroxide lotion, which is afterwards syringed
out with a warm saline solution, the cavity being dried with sterilized
strips of gauze, and finally packed from the bottom with a fresh strip.
The size of the graft, which is usually taken from the thigh, should be
at least 2 inches in width and 4 inches in length. The skin is cleansed
by washing it with soap and water, then with ether, and finally with
normal saline solution, the part being afterwards dried with a
sterilized towel. It does not matter what type of razor is used to
remove the graft, so long as it is sharp. The chief point to observe, in
order to secure success, is to see that the skin is kept uniformly
stretched--the tighter the better. The technique of removal of grafts is
described elsewhere (see Vol. I, p. 670). The graft taken from the leg
is transferred to a large spatula and smoothed out over its surface. The
auricle is now pulled forward, and the gauze strip is removed from the
mastoid cavity. The spatula is laid across the surface of the cavity so
that it rests on the anterior margin of the wound surface (Fig. 234).
With a sharp probe the edge of the graft, which just overlaps the
spatula, is held in position at this point, the spatula being gently
retracted so as to leave the graft stretched across the surface of the
wound cavity. With a ‘stopper’ (Fig. 235), the graft is now pushed
inwards towards the tympanic cavity.
A glass pipette (Fig. 236), having a curved beak, is then passed inwards
beneath the graft until its point, directed downwards, lies within the
tympanic cavity (Fig. 237). Any blood which has accumulated between the
bone and the graft is now sucked out, and in doing this the graft
becomes closely applied to the bone surface (Fig. 238). After removing
the pipette, any part of the graft which is not adherent to the bone is
smoothed out over its surface. The tympanic cavity and the innermost
portion of the mastoid cavity are then plugged with sterilized pellets
of cotton-wool wrapped in gauze and dusted with aristol powder. The
outer portion of the cavity is filled up with a strip of gauze, its end
being brought out through the external auditory meatus.
[Illustration: FIG. 234. SKIN-GRAFTING OF MASTOID WOUND CAVITY AFTER
OPERATION. Skin graft being transferred from the spatula to the mastoid
cavity.]
The posterior part of the graft, still projecting beyond the posterior
margin of the wound, is now turned forwards so as to form a covering
over the gauze filling up the wound cavity (Fig. 239). On the auricle
being restored to its normal position, this portion of the graft is
brought into contact with the subcutaneous tissues of the skin forming
the post-aural flap, which now forms the outer wall of the mastoid
cavity. The posterior incision is closed with sutures and a dry dressing
and bandage are applied to the ear.
[Illustration: FIG. 235. BALLANCE’S ‘STOPPER’ FOR PUSHING IN THE GRAFT.]
_If skin-grafting be performed a week or more after the primary
operation._ The post-aural wound, now healed, has to be reopened. In
doing so there may be considerable bleeding, which must be arrested. The
mastoid cavity is usually found to be covered with a fine layer of
granulations. They are curetted away carefully, special attention being
paid to the region of the Eustachian tube and the floor of the tympanic
cavity. After removal of the granulations, the bone should appear
uniformly smooth though somewhat vascular. If any points of carious bone
be found they should be removed freely with the gouge or burr.
Considerable time may have to be spent in arresting the oozing from the
surface of the bone cavity. This is best done by washing out the cavity
with hydrogen peroxide solution and then plugging it tightly for a few
moments with adrenalin solution. The gauze is withdrawn in a few
moments. If there be still oozing, the pressure will have to be repeated
until it ceases. The method of applying the graft is the same as already
described.
[Illustration: FIG. 236. PIPETTE FOR SUCKING AIR AND FLUID FROM BENEATH
THE GRAFT.]
[Illustration: FIG. 237. SKIN-GRAFTING OF MASTOID WOUND CAVITY AFTER
OPERATION. Skin graft in the act of being sucked into position by the
pipette.]
=After-treatment.= The outer dressing may be changed every second day,
but the wound itself is not interfered with until the eighth day. If
asepsis has been obtained, the posterior wound has usually completely
healed, so that the stitches can be removed at the first dressing. Owing
to the secretion from within the cavity there may be a certain amount of
odour, and as a rule some purulent discharge from the meatus. Under good
illumination the strip of gauze is gently removed through the meatus
and afterwards the small pellets of cotton-wool. In order to make
certain that all are removed, a note should be made at the time of
transplanting the graft as to how many were inserted in the wound
cavity. The ear is now syringed out gently with a weak solution of
hydrogen peroxide and afterwards dried by mopping it out with small
wicks of cotton-wool.
A speculum is next inserted into the meatus and the cavity thoroughly
examined. Any portions of the graft not in absolute contact with the
bone or which overlap the skin of the meatus will have died, and can be
removed by forceps. Care, however, must be taken not to pull off these
portions too forcibly, as in doing so other pieces of the graft may be
torn away. The external meatus is then plugged with a tiny piece of
gauze and a dry dressing applied. If the graft has not taken and has
died, it will be expelled at the first dressing on syringing.
[Illustration: FIG. 238. SKIN-GRAFTING OF MASTOID WOUND CAVITY AFTER
OPERATION. Skin graft in position.]
[Illustration: FIG. 239. POSTERIOR PORTION OF SKIN GRAFT COVERING OUTER
SURFACE OF WOUND CAVITY.]
Further treatment consists in syringing and afterwards drying the cavity
daily. From day to day the outer layer of the graft will gradually come
away piecemeal. At the end of the second week the patient can usually go
home and carry out the treatment for himself, but he should be seen by
the surgeon at least once a week until complete healing has taken place.
If the graft has not taken uniformly over the surface of the bone, small
patches of granulations may be seen covering these areas. Under cocaine
anæsthesia these patches should be curetted. If the granulations recur
repeatedly, it means that there is some underlying carious bone, and
that healing will not take place until the tiny fragment is eventually
exfoliated.
=Results.= Statistics vary. There is no doubt that the results are
better according to the experience of the surgeon with regard to
grafting. If it be only applied in those cases in which it is certain
that all the diseased bone has been eradicated at the primary operation,
then the percentage of success with relation to failure is very high.
If, however, skin-grafting be adopted as a matter of routine, the
ultimate result is probably not so good as in a similar series of cases
in which grafting has not been done.
=Skin-grafting through the external meatus.= This has been advised
chiefly in order to avoid a second operation.
The technique of applying the graft is practically the same as that for
transplanting a large graft. The same care must be taken to get the
interior of the mastoid cavity aseptic and dry. To avoid a general
anæsthetic, the small grafts may be removed from the arm or leg under
local anæsthesia produced by a subcutaneous injection of Schleich’s
solution. The graft is transferred from a small spatula to the edge of
the meatus and then coaxed into position within the cavity by means of
probes. The grafts are kept in position by small pellets of cotton-wool
covered with gauze. If successful, the grafting may shorten the duration
of the after-treatment. It is not, however, so satisfactory a procedure
as applying a large graft directly through the post-aural wound.
In order to keep the grafts in position, Drew has suggested laying the
graft on sterilized gold-beater’s skin, and in this way applying it to
the interior of the mastoid cavity.
More recently, Stoddart Barr of Glasgow has introduced an ingenious
method of getting the grafts into position. The graft is manipulated
over the end of a suitably-bent glass tube, having attached to the other
end a piece of rubber tubing with a glass mouthpiece or small rubber
bag. The graft at the end of the tube is passed through a wide speculum
to the inner wall of the tympanum, when, by blowing air through the
tube, the graft is spread out over the inner surface, including the
tympanic walls, aditus, and antrum.
AFTER-TREATMENT OF THE CASE
_If the posterior wound has been closed._ Provided the temperature keeps
normal and there be no pain and no head symptoms, the first dressing
need not take place until the fifth or sixth day. By this time the edges
of the skin incision have usually united, so that the stitches can be
removed, although occasionally the wound may have to be opened up to
permit of drainage on account of septic infection. The withdrawal of the
gauze from the auditory canal may cause considerable pain, which,
however, can be prevented by continuous irrigation of the ear before and
during its removal (see p. 315).
After the gauze has been removed, the ear is mopped out with pledgets
of cotton-wool. To relieve the pain a few drops of a sterilized 1%
solution of cocaine may be instilled and left within the ear for a few
minutes.
Under good illumination, the largest possible speculum is inserted into
the meatal orifice. The cocaine solution is mopped out, and the cavity
dried, in order that careful inspection of the deeper parts may be made.
The chief point is to see that the flaps are in position. There may be
slight oozing from the surface of the wound, but as a rule the bone
appears almost white, owing to the fact that granulations have not yet
begun to form. The wound is then packed gently and evenly with gauze and
the ear protected again with an external dressing and bandage.
Until the first dressing has taken place, the patient should be kept in
bed. After this, provided the condition be satisfactory, he may be
allowed to get up for a few hours every day, the period being gradually
increased; by the tenth day or so he is practically well. In an
uncomplicated case there is seldom any shock or discomfort after the
operation, so that frequently the patient is anxious to be up and about
even before the first dressing has been performed. It is wiser, however,
to insist on rest for the first few days.
The subsequent dressings should be done every second or third day,
depending on the condition found. If the wound cavity be clean, and if
there be no odour, it is sufficient to irrigate it with a simple saline
or boric lotion. Granulations begin to cover the bone about the tenth
day, when there may be some purulent discharge necessitating daily
dressings. To keep the parts sweet, an ear-bath of hydrogen peroxide (10
vols. %) may be given, the ear being subsequently irrigated with a 1 in
5,000 solution of biniodide of mercury.
Provided the patient be doing well there should be no temperature, pain,
nor headaches. If any of these symptoms occur, or if the patient feels
ill, or has attacks of sickness and becomes drowsy, the surgeon should
at once be suspicious of some impending intracranial complication.
If the case be progressing favourably and all the diseased area of bone
has been completely removed, granulations do not become exuberant, but
form a fine smooth layer over the wound surface, the last portion to
become covered being the region of the external semicircular canal and
the ridge forming the remains of the posterior wall of the bony meatus.
Exuberant granulation tissue is significant of underlying bone disease.
If patches be observed, a 10% or stronger solution of cocaine should be
applied to the part, which should afterwards be curetted. This process
may have to be repeated on several occasions until, perhaps, a small
spicule of bone is removed, after which granulations usually cease. As a
rule the bone is completely covered with granulations by the fifth or
sixth week. Meanwhile, owing to the growth of epithelium from the edges
of the flaps, the raw surface within the wound cavity gradually becomes
smaller, and with this there is diminished secretion.
The gauze packing can usually be discontinued about this period, or
considerably earlier, perhaps even by the third week. In its stead an
aqueous solution containing 50% of rectified spirit with 10 grains of
boric acid to the ounce may be instilled into the wound cavity after it
has been cleansed and dried.
Complete cicatrization of the cavity should take place within two or
three months, depending on the size of the cavity.
_If the posterior wound has been left open_, the first dressing should
be done on the second or third day.
The subsequent treatment depends on each individual case. If the wound
has been left open on account of its septic condition, or owing to the
dura mater having been exposed and found covered with granulations, its
edges may be brought together by sutures after a period of ten days or
so, when the wound cavity looks clean, and the packing carried out
through the meatus.
On the other hand, if the wound has been left open on account of bone
disease involving the inner wall of the tympanic cavity or region of the
Eustachian tube, the packing should be continued through the posterior
opening until the patches of carious or necrosed bone heal or are
exfoliated. In these cases the granulation tissue tends to become
fibrous in character in consequence of the necessary curettings, and
eventually to form a thickened pad covering the inner wall.
After complete healing has taken place, the patient, before being
dismissed, should be warned to visit the surgeon at least once in three
months. Owing to the large cavity being lined with epithelium,
desquamation takes place to a greater or lesser extent, so that the
wound cavity may gradually become filled with masses of epithelial
débris or cerumen. In consequence the cavity may become septic, and on
removal of the epithelial débris underlying ulceration may be found.
This can usually be cured by aseptic treatment, but if granulations have
already occurred, curetting and the application of trichloracetic and
chromic acid may be necessary.
DIFFICULTIES AND DANGERS OF THE OPERATION
_Anatomical difficulties._ The chief difficulties are due to a middle
fossa overlapping the antral cavity, a lateral sinus projecting far
forwards and lying superficially, and a sclerosed mastoid having no
landmarks to indicate the way into the antrum. Unfortunately these
conditions are frequently associated.
Formerly it was advised that it was wiser not to proceed further if the
antral cavity could not be discovered after chiselling to a depth of
three-quarters of an inch. This advice, however, is no longer reliable,
as by the combination of the Stacke, Wolf, or Küster-Bergmann method any
anatomical difficulties should certainly be overcome.
An inexperienced operator may mistake a large mastoid cell for the
antrum and in this way may get into difficulties. The opening into the
antrum, however, can always be identified by passing a bent malleable
silver probe in an inward and forward direction into the aditus. If only
a large cell has been opened, the probe will show that it is a limited
cavity.
_Hæmorrhage._ In the majority of cases this is more of an inconvenience
than a danger, being chiefly due to a general oozing from the soft
tissues. It is, however, very necessary that the surgeon should have a
clear view of the deeper parts whilst operating. If he works blindly in
a pool of blood he courts disaster.
The hæmorrhage is best prevented by first curetting away any granulation
tissue and then packing the cavity firmly with a strip of gauze. If this
be not sufficient, it may be again packed with gauze containing
adrenalin solution. It will repay the surgeon to have a good assistant
to keep the field of operation dry. Troublesome bleeding, coming from a
small vessel in the bone, may be arrested by the local application of a
small fragment of Horsley’s sterilized wax (see Vol. I, p. 437).
_Wound of the lateral sinus._ This is a serious matter for two reasons:
firstly, it may prevent completion of the operation; and secondly, it
may lead to infection of the sinus.
If the sinus has already been exposed before the accident occurs, the
surgeon promptly arrests the hæmorrhage by placing the forefinger of his
left hand directly over the wound in its wall and exerts sufficient
pressure to completely obliterate the sinus at this point. With his
finger kept in this position, the wound cavity is carefully dried, and,
if there be sufficient room, a piece of sterilized gauze is then packed
between the bone and the outer wall of the sinus, both above and below
the site of the injury. If there be not enough room to do this, then the
surgeon with his right hand, or the assistant, should punch away more
bone by means of bone forceps. After the lumen of the sinus has been
obliterated above and below the injured area, the finger may be removed.
If the packing has been successful, there will be no bleeding; if there
be still slight bleeding, it can be controlled by further pressure. If
possible, this method should always be carried out, as it practically
excludes any chance of after-infection of the sinus.
If the injury takes place before the sinus has been sufficiently
exposed to permit of direct pressure with the finger, then the only
thing to do is to press in a small strip of gauze and plug the opening.
As to what should be done next is a matter of opinion. Some surgeons are
content to leave the gauze _in situ_. The author prefers to expose the
sinus further, as in the former case, and to make certain that it is
obliterated above and below the injured area. No doubt, if the injury be
slight, the pressure of the strip of gauze covering the puncture will be
sufficient to control the hæmorrhage, and the patency of the sinus may
be maintained on healing. At the same time infection of the sinus has
been known to take place, although the symptoms of this may not occur
for ten days or two weeks after the operation.
If the sinus projects far forwards the gauze plugs may so inconvenience
the operator as to prevent him completing the operation, which therefore
may have to be delayed for at least a week. If, however, the sinus be
injured at an early stage of the operation and the symptoms for which it
is being performed are urgent, then, in spite of all difficulties, the
antrum, at any rate, must be opened to permit of drainage, the operation
being completed at a later date.
_Injury to the facial nerve._ The nerve may be injured in any part of
its course within the tympanic cavity, or in its vertical course through
the stylo-mastoid canal. To avoid this injury, curetting of the tympanic
cavity should always be performed gently, and care should be taken not
to chisel too low down,--the usual fault of the inexperienced.
Twitching of the face means that the nerve has been touched. If the
patient be under deep anæsthesia, it is difficult to say whether the
nerve has been injured or divided. In a case of doubt, it is wiser to
discontinue the anæsthetic until the conjunctival reflex returns, when
it can easily be demonstrated whether the facial nerve is affected or
not.
If the injury be the result of curetting, it is wiser to do nothing.
Recovery almost invariably takes place, owing to the fact that the
paralysis has been caused by slight injury of the nerve. If, however,
the nerve has been chiselled through, and the injury has occurred in its
lower portion, it should be freely exposed over this area. The severed
ends of the nerve should then be approximated and left _in situ_. In
this case permanent paralysis is possible.
The after-treatment consists in avoidance of pressure in packing, the
giving of strychnine internally, and faradism or galvanism to keep up
the tone of the facial nerve and the muscles it supplies. Careful
testing of the electrical reaction will show whether nerve regeneration
is taking place or not. If the paralysis has existed for six months, and
if in addition there be a definite reaction of degeneration, then the
question of anastomosing the peripheral portion of the facial nerve to
the spinal accessory, or what is more advisable, to the hypoglossal
nerve, may be considered (see Vol. I, p. 452).
_Injury to the labyrinth._ Of the semicircular canals the external is
the more liable to injury. The cochlea may also be injured from violent
curetting of the promontory, or infected from dislodgment of the stapes;
or it may even happen that a careless operator may inadvertently chisel
through the promontory itself. In consequence of these accidents,
vertigo, vomiting, and nystagmus may persist for several days, but as a
rule they gradually diminish and disappear.
The treatment is expectant. As a result of pyogenic infection,
suppuration of the labyrinth may occur. Even if this does not take
place, complete deafness may result.
_Injury to the dura mater._ The subsequent danger is meningitis,
fortunately a rare occurrence. The immediate treatment is to irrigate
the part with weak biniodide of mercury solution, and then to remove
more bone over the site of the injury. The intracranial pressure will
keep the dura mater in close contact with the bone, so that if
subsequent infection occurs there will be free drainage. The site of
injury should be carefully isolated from the general mastoid wound
cavity by covering it with sterilized gauze. If signs of meningeal
irritation occur, the wound should be inspected, and if there be any
evidence of localized meningitis, it should at once be surgically
treated.
RESULTS OF THE OPERATION
=With regard to life.= If, at the time of the operation, the disease be
limited to the mastoid cavity, there should be no immediate danger to
life.
=With regard to recovery.= (i) _The operation is successful._ Roughly
speaking this occurs in at least 80% of the cases, complete healing
taking place within eight to twelve weeks. If skin-grafting has been
successfully performed the duration of healing may be considerably
shorter. If the bone disease has been eradicated with complete healing
of the cavity, the possibility of intracranial complications in the
future can be excluded. On this account the patient may be considered as
a healthy individual from an insurance point of view.
(ii) _The after-treatment may be prolonged._ The chief causes of delay
in healing and continuance of the suppuration are sepsis and caries of
some part of the bony wall, usually the promontory or floor of the
tympanic cavity, or around the orifice of the Eustachian tube. In the
former case the use of ear-baths of hydrogen peroxide or of rectified
spirit, or frequent syringing of the cavity with a weak biniodide of
mercury solution, and afterwards drying it and protecting it with gauze,
may be sufficient to effect a cure. In the latter case the local
condition must be treated.
Another condition delaying cure is reinfection from the throat through a
patent Eustachian tube. In this case, although the mastoid cavity
becomes lined with epithelium, mucous membrane may still cover not only
the region around the Eustachian orifice, but the main portion of the
tympanic cavity. The chief object in these cases is to close the orifice
of the Eustachian tube. Sometimes this can be done by curetting under
cocaine; in other cases by actual cauterization. After closure has been
obtained, the cavity should be dried and gently packed with gauze
impregnated with boric acid or aristol powder.
Again, cholesteatomatous formation may be the immediate cause of
relapses. In these cases it is very difficult to remove all the diseased
tissue. Even although the patient may apparently be cured, yet, unless
kept under close observation, recurrence of cholesteatomatous masses
take place, and frequently cause further caries of the underlying bone.
Finally, delay in healing may be due to careless after-treatment: if the
cavity has not been properly packed, granulations spring up in the
region of the aditus and gradually form a partition between the mastoid
and tympanic cavities. If this takes place, further disease of the bone
may occur owing to the retention of the secretion.
(iii) _Symptoms may occur pointing to some intracranial complication_,
and further operation may become necessary.
=With regard to hearing.= The hearing power depends not only on the
condition before operation, but also on the result of the
after-treatment. The average hearing power after the removal of the
malleus and incus is about 12 feet off for ordinary conversation. The
same result should be obtained after the complete mastoid operation,
provided there be no internal-ear deafness and provided the stapes be
not already ankylosed within the fenestra ovalis. If the patient before
operation hears conversation at a greater distance than 12 feet he
should be told that the hearing power may be reduced to this amount. If,
however, there be considerable deafness, due to polypi or granulations
blocking up the tympanic cavity and auditory canal, the hearing power
may be improved by the operation. The ultimate hearing depends on the
condition of the stapes within the fenestra ovalis: if it remains freely
movable, the hearing power may be extremely good. The great object,
therefore, of the after-treatment is to prevent the inner wall of the
tympanic cavity becoming covered with granulations which may become
organized later into a fibrous pad covering the inner wall of the
tympanic cavity, and thus prevent movement of the stapes and, in
consequence, marked deafness. The prevalent idea that the hearing power
is destroyed irrevocably, as a result of the complete operation, is
quite wrong: equally so is the harmful statement that, as a result of
this operation, complete restoration of the hearing can be obtained.
CHAPTER VII
OPERATIONS UPON THE LABYRINTH
GENERAL CONSIDERATIONS
Labyrinthine suppuration usually occurs in the course of a chronic
middle-ear suppuration; more rarely, as the result of tuberculous
disease of the temporal bone, or in consequence of an acute middle-ear
suppuration. In the latter case, however, it is a matter of experience
that, although symptoms of labyrinthine suppuration may be present, they
almost invariably subside as a result of drainage of the middle ear and
mastoid. This is an important point which should be remembered, as
otherwise the labyrinth may be explored unnecessarily at a considerable
risk to the patient’s life.
The most frequent paths of extension of the pyogenic infection from the
middle ear to the internal ear are through the external semicircular
canal, the promontory, and the fenestra ovalis, the result of
cholesteatomatous erosion, caries, or necrosis. Hinsburg, in 198 cases
of labyrinthine suppuration, traced the infection in 61 cases. In 27
cases the infection had entered through the external semicircular canal,
in 17 through the fenestra ovalis, in 7 through a fistula of the
promontory, in 5 through the fenestra rotunda and ovalis, and in 5
through a fistula in the posterior or superior semicircular canal
(_Archives of Otology_, 1902, vol. xxxi, p. 116).
Although operations on the labyrinth are practically limited to
suppurative disease, yet under certain conditions they are justifiable
when no suppuration is present.
These operations may consist in partial or complete opening of the
semicircular canals, or of the vestibule, or in removal of the cochlea,
or complete extirpation of the labyrinth.
INDICATIONS FOR OPERATION
(i) =In non-suppurative labyrinthitis.=
(_a_) _To relieve vertigo._ This operation is only justifiable if the
condition cannot be cured by other methods, and is so distressing as to
render the patient’s life unendurable.
In such cases it is first essential to make certain that the attacks of
vertigo originate from some lesion within the semicircular canals. For
this reason the other forms of vertigo must be excluded, and, in
addition, there should be evidence of definite involvement of the
labyrinth, such as falling over of the patient to the affected side,
internal-ear deafness, or post-suppurative changes within the middle
ear, suggestive that the internal ear has also become affected. It must,
however, be remembered that it is possible, though extremely rare, for a
lesion, limited to the semicircular canals, to produce marked vertigo
without any deafness being present, in which case the operation will be
limited to extirpation of the semicircular canals.
(_b_) _To relieve tinnitus._ If the tinnitus be unbearable and all other
measures have failed to cure it, the question of extirpation of the
cochlea, in order to destroy the nerve-terminals, may be discussed. This
operation, so far, has not been completely successful, and therefore it
cannot be recommended.
In this connexion it may be mentioned that, instead of attacking the
cochlea, it has been proposed to divide the auditory nerve before it
enters the internal meatus. Charles Ballance has recently described such
a case.
The difficulty of this latter operation and the very slight chance of
cure which it offers, owing to the tinnitus probably being central, are
sufficient to raise the question as to whether such an operation is
really justifiable.
(ii) =In suppurative labyrinthitis.= The object of the operation is to
remove the infective focus and, by permitting drainage, to prevent
further complications, such as meningitis or intracranial suppuration.
Before deciding the question of operation every means available should
be used to determine: (1) whether the symptoms are merely the result of
disturbance of the labyrinthine function in consequence of suppuration
still limited to the tympanic and mastoid cavities; (2) whether the
labyrinthine lesion is localized or general; (3) whether the
labyrinthine suppuration is associated with some intracranial
complication, more especially meningitis or cerebellar abscess.
Suggestive of labyrinthine suppuration are vertigo, vomiting,
spontaneous nystagmus, and disturbances of the equilibrium. In the more
acute cases there may be loud tinnitus, pyrexia, rapid onset of deafness
(with inability to hear high tuning-forks and loss of bone conduction),
facial paralysis, and deep-seated pain.
In addition much information may be gained by determining the character
of the _spontaneous nystagmus_, if present, or whether nystagmus can be
elicited by _Bárány’s caloric tests_.
(_a_) If the ear be normal, there is no spontaneous nystagmus.
If, however, the ear be syringed with water above or below the body
temperature, a rotatory nystagmus will be obtained if the patient’s
head is kept in the erect position, or a horizontal nystagmus if the
patient is lying in the horizontal position with the face upwards.
Syringing with hot water causes a nystagmus directed _towards_ the ear
syringed; syringing with cold water, _away from_ the ear.
(_b_) If there be a localized labyrinthine lesion, and the function of
the labyrinth is still maintained, the same results will be obtained on
syringing. Care, however, must be taken that the syringing is not
forcible, otherwise the caloric tests will be unreliable, as in these
cases nystagmus may be produced on even slight increase of pressure
within the external auditory canal, and with this there may be a
sensation of giddiness and nausea.
Spontaneous nystagmus, however, will probably be present, and will be
directed towards the affected side. This spontaneous nystagmus is
greatly modified by the caloric tests, being strongly exaggerated on
syringing with hot water, and weakened or arrested on syringing with
cold water.
(_c_) If the function of the labyrinth be destroyed, as in suppurative
labyrinthitis, nystagmus will not be produced as a result of the caloric
tests, but the spontaneous nystagmus, if present, will be directed
towards the opposite, the normal side.
These various tests must be taken in combination with the symptoms, and
frequently are of extreme value in deciding whether operation is
indicated or not.
The chief difficulty is to exclude the possible existence of a
cerebellar abscess (see p. 460). In favour of labyrinthine inflammation
is complete internal-ear deafness, although this in itself does not
exclude an accompanying intracranial lesion.
1. _Immediate exploration of the labyrinth is indicated_ (provided there
is internal-ear deafness):--
(_a_) If symptoms of _acute_ labyrinthine suppuration occur in the
course of a middle-ear suppuration, even although at the time of opening
of the mastoid no definite fistula of the labyrinthine wall can be
discovered.
(_b_) If symptoms of involvement of the labyrinth be present and a
definite fistula is found on operation.
(_c_) If symptoms of a cerebellar abscess or of meningeal irritation be
present in addition to those suggestive of a labyrinthine affection.
2. _Opening of the labyrinth should be delayed_ if Bárány’s and other
tests show that the labyrinth is not yet destroyed:--
(_a_) If, in spite of clinical symptoms pointing to involvement of the
labyrinth, pus be found under tension within the tympanic cavity or the
mastoid process.
(_b_) If the symptoms before operation consist only of attacks of
vertigo and nystagmus, and on operation merely an erosion of the outer
wall of the labyrinth (usually the external semicircular canal) is
discovered.
In the above cases, if the symptoms be due to irritation of the
labyrinth, a rapid recovery is to be expected as a result of the mastoid
operation. If, however, they continue or become progressively worse,
then the wound cavity must be reopened and the labyrinthine wall
carefully examined and further operation undertaken.
The reader may again be reminded that although exploration of the
labyrinth is indicated when it is certain that a suppurative lesion
exists, yet it is a very serious mistake to open up a labyrinth not yet
infected.
Although a great advance has been made in the last few years with regard
to operations on the labyrinth, yet there is still much to be learnt,
not only with regard to the indications for operation but the result
obtained by operation. Now that operations on the labyrinth have become
universal, the general tendency is to operate on the immediate
occurrence of symptoms of labyrinthine irritation without waiting to see
whether simple opening of the mastoid process will not be sufficient--a
matter much to be regretted.
=Surgical Anatomy.= The facial canal, it will be remembered, extends
horizontally backwards above the promontory, and passes downwards
superficially to the inferior portion of the vestibule which lies
between the fenestra ovalis below and ampullary ends of the external and
superior semicircular canals above. The nerve then extends directly
downwards towards the stylo-mastoid foramen, being situated deeply
within the posterior meatal wall.
Of the semicircular canals the external is the most prominent, and the
only one visible during the performance of the ordinary mastoid
operation; its outer border forms the inner and lower boundary of the
aditus, and can usually be recognized as a white eminence. The superior
semicircular canal can only be seen on careful removal of the overlying
bone; its ampullary end is found lying just above that of the external
canal. It forms the highest point of the labyrinth, becoming fused with
the innermost portion of the tegmen tympani, and is in such close
relationship with the upper surface of the petrous bone as to cause a
smooth elevation on its surface. It is at this point in the operation of
removal of the semicircular canal that the greatest risk is encountered
of breaking through the petrous bone and of injuring the dura mater.
The posterior semicircular canal lies at right angles to the external
canal, and is best exposed by careful removal of bone just posterior to
the latter (see Fig. 240).
The outer half of the first whorl of the cochlea is formed by the
promontory. Anteriorly it is in close relationship with the carotid
canal, whilst below it lies the dome of the jugular fossa. Medially the
modiolus is only separated from the internal auditory meatus by a very
fine rim of brittle bone, which can easily be broken; a mishap which may
permit of escape of the cerebro-spinal fluid, and also of possible
infection of the meninges through the internal meatus.
METHODS OF OPERATING
These operations may be divided into: (1) simple curetting away of a
localized lesion of the labyrinthine wall; (2) opening up of the
vestibule with removal of the semicircular canals; (3) opening of the
cochlea; (4) a combination of these methods--extirpation of the
labyrinth.
=Curetting away of a localized lesion of the labyrinthine wall.= It has
been already stated that, provided the labyrinth be not yet destroyed,
it is not justifiable to explore it on the mere discovery of an erosion
of the semicircular canal. At the same time, if a definite fistula from
which granulations protrude is present, a small fragment of bone may be
chipped away, the granulations being afterwards removed by the curette.
Unless pus is found to exude from the labyrinth, it is not necessary to
do anything further at the present moment. If, however, at a later
period, symptoms of labyrinthine infection occur, then it is necessary
to further explore the semicircular canal and vestibule, the extent of
the operation depending on what is discovered at the time of the
operation.
Sometimes an examination of the tympanic cavity may be prevented before
operation owing to the auditory canal being filled with polypi or
granulations. On performing the complete mastoid operation and curetting
away these granulations and polypi, a fistula may be found in the
promontory, and carious bone may be felt on probing. Not infrequently
these cases are tuberculous in origin and are accompanied by facial
paralysis. Provided there be no labyrinthine symptoms, it is sufficient
to curette out the granulations, but only gently. Violent curetting may
break through the barrier between the infected area and the internal
meatus and so lead to meningitis. It is wiser to curette too little than
too much.
A further condition which may be met with is necrosis of a portion of
the promontory, or of the walls of the vestibule, or of the semicircular
canals. If the sequestrum be not quite loose at the time of operation,
it should be left _in situ_, provided there be no intracranial symptoms.
In fact, there is less danger in leaving the sequestrum than in
attempting to remove it. After the operation, the wound cavity is kept
open, so that the sequestrum can be removed at a later date after it has
separated from the living bone.
=Opening the vestibule= (with partial or complete removal of the
semicircular canals). This may be performed by one of the following
methods:--