sutures. It is very important that every precaution should be taken to
prevent the continued escape of cerebro-spinal fluid, and, for this and
other obvious reasons, it is necessary to avoid drainage whenever
possible. If such a course should be necessary--by reason of
hæmorrhage--a cigarette drain may be brought out at the most dependent
and convenient angle of the dural flap, and through one of the trephine
holes or gap purposely cut in the bone-flap.
In any case, the bone-flap is replaced, resting on its shelf and
anchored by means of numerous deep sutures, each of which picks up the
aponeurosis or muscle both along the upper border of the flap and the
two downward vertical prolongations. These sutures will also control
bleeding from the divided scalp-vessels. The tourniquet is removed,
dressings applied, and the whole maintained firmly in position by a
gauze bandage applied circumferentially. These dressings are supported
by bandages and the patient sent back to bed.
If the tumour has been exposed by _craniectomy_, the gap in the skull
will probably require protection. This procedure (see Chapter VI) can be
carried out at the termination of the main operation or at a later date.
This latter course is to be preferred.
=Radical operation for cerebellar tumours.= Craniectomy may be regarded
as the operation of choice in the exposure and removal of cerebellar
tumours. The formation of an osteoplastic flap is contra-indicated (see
p. 29). The operative procedures vary according as to whether it is
desired to expose the one or both cerebellar hemispheres. Bilateral
exposure, though presenting the great advantage of offering a larger
field for exploration, is by far the more serious of the two operations.
_Unilateral cerebellar exposure._ The patient being placed in the
semi-prone or face-down position, the incision starts at the posterior
border of the apex of the mastoid process, curves inwards along the
superior curved line of the occipital bone to the occipital
protuberance, and then passes straight down the middle line of the neck
for 2 to 3 inches. If the incision is deepened at once to the bone,
hæmorrhage is severe. The incision should first involve the skin and
then the muscles attached to the occipital bone. Each vessel as
encountered is clipped and tied. The flap must be turned down right up
to the posterior margin of the foramen magnum.
The flap being held aside, the pin of the trephine is placed in such a
manner that the disk to be removed will correspond to the thin central
portion of the cerebellar fossa. The trephine, placed low down, is
directed more or less towards the anterior fontanelle.
The disk being removed, the bone is freely cut away with rongeur
forceps--outwards to the posterior border of the mastoid process,
upwards to the curved line, inwards to near the middle line, and
downwards to the posterior margin of the foramen magnum.
This generally completes the first stage of the operation, for, in
cerebellar tumours, it is usually advisable to complete the operation in
two stages. The scalp-flap is replaced, lightly sewn into position, and
the patient sent back to bed.
A few days later the flap is again turned down, the dura incised, and
turned down as a flap the convexity of which corresponds to but falls
short of the line of the lateral sinus. The cerebellar substance is then
examined and the tumour removed after the lines enumerated in dealing
with cerebral tumours. Greater difficulty, however, is experienced in
the attempted removal of cerebellar tumours, for the operator is working
in a very confined space, and because the cerebellum tends to herniate
through the adventitious hole in dura and bone. Two other factors must
be taken into consideration: (1) the danger incident to all cerebellar
operations of respiratory failure,[48] and (2) the friability of the
cerebellar substance. Every care must be taken to avoid unnecessary
damage of the brain-matter.
When the tumour is situated in the cerebello-pontine angle, a somewhat
favourite site for tumour formation, ‘lateral displacement’ of the
cerebellum towards the middle line will aid considerably in the
exposure. A flat retractor, bent to a suitable curve, is introduced
between the dura and the cerebellum, and the brain-matter gently but
firmly retracted towards the middle line. As the brain yields to the
pressure the tip of the retractor is insinuated towards the posterior
surface of the petrous bone. With the aid of a head-lamp a good view may
usually be obtained of the region involved, and, as the tumour is but
lightly attached, its removal can be undertaken.
The dura is then carefully sutured and the scalp-flap accurately
replaced, deep sutures for the muscles and a few surface sutures for the
skin. Drainage should be avoided whenever possible--the discharge of
cerebro-spinal fluid is fraught with considerable danger. The gap in the
skull requires no other protection than that afforded by the mass of
neck muscles.
[Illustration: FIG. 73A. UNILATERAL EXPOSURE OF THE LEFT HALF OF THE
CEREBELLUM BY CRANIECTOMY. The scalp-flap has been turned down and is
fully retracted. The cerebellum has been exposed by means of a
crescentic dural flap.]
[Illustration: FIG. 73B. BILATERAL EXPOSURE OF THE CEREBELLUM BY
CRANIECTOMY. The left half of the cerebellum has been exposed. The
trephine is being applied over the right cerebellar region. Note the
position of the trephine and the direction in which it is being
applied.]
[Illustration: FIG. 73C. BILATERAL EXPOSURE OF THE CEREBELLUM BY
CRANIECTOMY. The walls of both cerebellar fossæ have been cut away,
exposing the bulging dura mater. The Gigli saw is in position for
removal of the bridge of bone intervening between the two cerebellar
fossæ.]
[Illustration: FIG. 73D. BILATERAL EXPOSURE OF THE CEREBELLUM BY
CRANIECTOMY. The bridge of bone has been removed, two crescentic flaps
of dura mater have been turned down, and the falx cerebelli has been
ligatured in two places and divided.]
_Bilateral cerebellar exposure._ This operation is also done in two
stages. In the first, each cerebellar fossa is exposed in turn, the
scalp-flap being framed and the trephining and cutting away of the bone
carried out in the manner previously described for unilateral exposure.
The osseous bridge which separates the two openings in the skull is
divided above and below with Gigli’s saw, and the intermediate part
removed. This completes stage one.
In the second stage, again carried out a few days later, two dural flaps
are turned down, each similar to the one described in unilateral
exposure. This leaves a central portion of dura, that part which
encloses the occipital sinus and to which the falx cerebelli is
attached. By means of an aneurysm needle, threaded with catgut, passed
through or around the falx, the occipital sinus is ligatured above and
below, the ligatures being applied as high and as low as circumstances
permit. The falx is then divided between the two ligatures and the two
flaps thrown upwards and downwards respectively.
The extra space so afforded not only allows of the exposure of both
hemispheres, but also permits of the further dislocation of the one lobe
towards the opposite side, thus facilitating the examination of the
lateral aspect of the cerebellum and of the cerebello-pontine angle.
This bilateral method is a serious operation. Hæmorrhage may be severe,
and the attendant risks of respiratory failure are not inconsiderable.
It should only be adopted (1) when a tumour is so situated or so
extensive that more space is required than supplied by unilateral
exposure, and (2) when bilateral cerebello-pontine tumours are
suspected.
=Palliative operations for cerebral and cerebellar tumours.= A primary
palliative operation may be conducted over the region of the tumour
itself, in the cerebellar region, or over the temporal lobe--one of the
so-called ‘silent’ areas of the brain.
It is obvious that the greatest degree of pressure relief will be
obtained by craniectomy conducted over the region of the tumour itself.
To this course, however, there are two great objections: (1) the exposed
cortex most commonly includes the motor area, herniation of which will
lead to disastrous effects on the extremities of the contra-lateral
side--spasticity, paralysis, aphasia, &c.; and (2) the herniation of
brain-matter including, or closely related to, an irremovable tumour
tends to lead to œdema of the brain tissues and softening of and
hæmorrhage into the growth, with subsequent rapid development of the
outwardly protruded mass.
With respect to cerebellar decompression operations, I must confess that
I have formed a most unfavourable opinion. The subtentorial pressure can
undoubtedly be relieved most effectually by such methods, but the
immediate results are not infrequently disastrous, the patient dying
within a few days as a result of the complete upset of medullary
centres.
In the event of the surgeon deciding to confine his attempts to
palliative treatment--alleviation of symptoms only--the _subtemporal
operation_ of Cushing is certainly the method of choice. The technique
of the operation and its general advantages have already been discussed.
It merely remains to add that, when the operation is conducted for
tumour relief and not for injury as discussed in Chapter IV, no attempt
is made to explore the temporo-sphenoidal lobe and drainage is
contra-indicated. The dura, widely incised, is left open, the temporal
muscle and fascia accurately sutured, and the scalp-flap secured with
fine silk sutures.
With regard to the side on which this subtemporal decompression
operation is to be conducted, the best results are obtained by operating
on that side on which the tumour is situated. In the event of doubt, the
right side is chosen, so avoiding any possibility of including, in the
hernial protrusion, the motor speech area of Broca. The cranial defect
should be made as large as possible, and in the event of failure in
bringing about adequate decompression, a similar operation is conducted
at a later date on the opposite side of the skull.
After subtemporal decompression there should be no mortality.
The immediate results are eminently satisfactory--headache is relieved,
optic neuritis steadily diminishes, vomiting ceases, and the general
condition of the patient is immensely improved.
The expectancy of life after such decompression operations requires
careful consideration. So much depends on the nature of the tumour that
it is difficult to make more than a general observation. In many cases
life has been prolonged for one to two years, whilst instances are
recorded in which the patient has lived for five to six years--not in a
miserable condition as might be imagined, but in comparative comfort.
It might be added that, as the tumour grows, a one-sided subtemporal
decompression may gradually become insufficient. In such cases,
recrudescence of symptoms--redevelopment of optic neuritis, &c.--may be
met by further decompression on the opposite side of the head.
=Operations for tumours of the pituitary body.= The pituitary body may
be approached by the frontal, temporal, and nasal routes. The _temporal
route_, advocated by Caton and Paul[49] and Horsley, possesses the
disadvantage that the surgeon, whilst utilizing an approach similar to
that used in the Hartley-Krause operation for trigeminal neuralgia,
encounters on his way the structures laterally situated to the pituitary
body, the internal carotid, the cavernous sinus, the third, fourth, and
sixth nerves, and the ophthalmic division of the fifth. The anatomical
difficulties are therefore considerable. Added to this, the tumour, in
its hollowing out of the central portion of the sella turcica, may leave
such lateral osseous walls that an approach from the side is impossible.
The _frontal route_ is strongly advocated by Krause.[50] He states that,
‘an osteoplastic flap is framed in the frontal region, immediately to
one side of the middle line, so as to avoid the superior longitudinal
sinus and frontal air sinus, and turned upwards. It is essential that
the operator should approach the tumour along the floor of the anterior
fossa, and, for this purpose, it may be deemed necessary to chip away
the bone in the region of the supra-orbital ridge. Some days later, the
final stages of the operation are conducted. The dura mater covering
the frontal lobe is stripped away from the bone and traction applied to
the dura by means of broad flat spatulæ. When the lesser wing of the
sphenoid is exposed, the dura mater is opened in the vertical direction
on a line with the lower median angle of the wound at a depth of 5 to
5¹⁄₂ centimetres, as measured from the anterior surface of the frontal
bone. If the incision is made at a deeper point there is danger of
injury to the optic nerve, which is covered with dura mater in this
situation. Laterally the dura is opened parallel to the posterior border
of the lesser wing of the sphenoid, about ¹⁄₂ cm. in front of it, to
avoid the sinus which lies immediately in contact with the edge of the
bone. This exposes the optic nerve, coming from the chiasma and the
internal carotid. The pituitary body is located beneath the anterior
edge of the chiasma. The diaphragm of the sella turcica is now carefully
incised with a small hook-shaped scalpel, and the hypophysis is readily
removed.’
The _nasal route_, advocated by Bruns and successfully carried out by
Schloffer[51] and Cushing, seems to offer the greatest advantages and
give the most successful results. The general details of the operation
are as follows: starting either beneath the upper lip or externally at
the base of the septum, the mucous membrane is peeled away from each
side of the vomer, and, by gradual piecemeal removal of that bone, the
advance is carried out towards the base of the skull in what may be
called an intra-mucous space. By the introduction of suitable
instruments into this space the cavity is gradually enlarged, at the
expense of the turbinated bones which are compressed by the dilating
instruments. By this means--gradual removal of the septum--the operator
approaches the base of the skull, always working between the two layers
of mucous membrane, and always avoiding, with the greatest care, any
laceration of the same. Laceration at once converts the more or less
aseptic operation into an infected one. When the base of the skull is
laid bare in the region of the sphenoidal sinus, the bone is there
chiselled away and the under surface of the pituitary body exposed. It
can then be removed piecemeal.
The general details of the operation as enumerated above may require
amendment as our knowledge increases. Sufficient has been said,
however, to point out the various methods of approach and the advantages
claimed for the nasal route.
=Results of operation on brain tumours.= Statistics are always
fallacious, and this is especially the case with regard to operations on
tumours of the brain. Few surgeons have operated on a sufficient number
of cases to compile satisfactory statistical tables. These tables are
generally made up from the combined experience of many operators, all
using their own methods. The following, however, will serve to give an
approximate idea as to mortality, &c.
_Mortality._ From earlier records the immediate mortality was estimated
at 30-40 per cent. Duret, however, records 400 cases with a mortality of
19·5 per cent., 58 cases dying from shock, 10 from hyperpyrexia, and 10
from hæmorrhage. In my own practice, the mortality may be estimated at a
much lower figure. Perhaps I may be too conservative, but I hold the
view that, unless the tumour is readily exposed and equally readily
removable, it is inadvisable to carry out further measures for its
eradication. Moreover, the general technique of brain surgery has
advanced with rapid strides, and the question of early and accurate
localization has received equal attention. The mortality has diminished
proportionately, and may be estimated at less than 20 per cent. So much
depends on the surgeon and on the nature of the tumour, its position and
localization, that it is impossible to make any absolute statement as to
the risk to life attendant on operation. If all tumours were fibromata,
cortically situated, and accurately diagnosed, the operation, in the
hands of a skilled neurological surgeon, should present but a very low
mortality. So long, however, as surgeons will persist in burrowing into
the brain substance for a supposed subcortical tumour, so long will the
mortality remain high. The great secret in operating on a brain tumour
lies in knowing when to terminate the attempt at removal of the tumour
and when to rest content with a pure ‘decompression’.
It is obvious, therefore, that cortical tumours--more especially such as
give rise to early localizing symptoms, e.g. Rolandic tumours--offer a
better prognosis than when the surgeon has to deal with subcortical,
central, and basal tumour formation.
_The mortality according to the region affected._ The following table,
from a series collected by Knapp, supplies valuable information as to
the regional mortality.
Frontal tumours 32 cases Mortality, 25 per cent.
Central „ 231 „ „ 23 „
Parietal „ 29 „ „ 41 „
Temporal „ 17 „ „ 29 „
Occipital „ 10 „ „ 20 „
Cerebellar „ 54 „ „ 45 „
Sir Victor Horsley draws attention to this question in the following
manner: ‘If a line be drawn from the frontal eminences to the occipital
protuberance, it is obvious that more shock results from operations
below that line than from above, and as we proceed from the frontal to
the cerebellar pole of the encephalon.’
_The mortality according as to whether the tumour is found or not._
According to Horsley, of 79 cases in which a correct diagnosis was made
and the tumour removed, 7 died from shock; whilst in 16 cases
inaccurately diagnosed, 6 died--a mortality of 9 per cent. in the first
case as against 37 per cent. in the second.
The added danger resulting from unsuccessful attempts at finding the
tumour must not be advanced as an argument against the palliative
operations, for the failure to find and remove the tumour implies
diligent search for the neoplasm, with necessary prolongation of
operative procedures, and perhaps extensive manipulation of the brain
substance. Statistics and experience both afford conclusive evidence
that accurate localization is essential for the success of the
operation.
[39] Paton, _Brain_, vol. xxxiii, p. 67.
[40] _Pyschische Störungen bei Hirntumor_, 1903.
[41] _Lettsomian Lectures_, by the late Dr. Charles Beevor; Duret,
_Tumours of the Brain_; Nothnagel, _Tumours of the Brain_, &c.
[42] _Brit. Med. Journal_, March 1, 1908.
[43] _Lancet_, July 10, 1909.
[44] Crowe, Cushing, and Homans, _Johns Hopkins Bulletin_, May 1910.
[45] _Lancet_, April 15, 1904.
[46] _Brit. Med. Journal_, October 26, 1906.
[47] _Annals of Surgery_, 1907, p. 543.
[48] In the event of cessation of respiration during trephining, the
skull should be opened and the dura incised with the utmost expedition.
The relief of tension so afforded often allows of respiratory
recovery--with or without artificial respiration.
[49] _Brit. Med. Journ._, 1893, p. 1421.
[50] _Surgery of the Brain_, vol. i, p. 117.
[51] _Wien. klin. Wochensch._, No. 21, 1907.
CHAPTER VIII
THE INFECTIVE DISEASES OF THE BRAIN AND MENINGES: ABSCESS OF THE BRAIN,
MENINGITIS, LATERAL AND CAVERNOUS SINUS THROMBOSIS, HERNIA CEREBRI
ABSCESS OF THE BRAIN
Abscess of the brain may be considered under the following headings:--
Multiple abscess.
Acute traumatic abscess.
Chronic abscess.
=Multiple abscess.= Multiple abscess results from the lodgement of
infected emboli which, derived from an acute infective osteomyelitis,
endocarditis, gangrene of the lung, &c., are carried by the blood-stream
to the brain. Multiple abscess of the brain may therefore be considered
as part of a general infection. On account of the symptoms dependent on
the primary infection and on the secondary pyæmic developments, a
diagnosis can seldom be determined, and, even in those rather
hypothetical cases in which suspicion may be aroused, surgical
interference is quite useless and the prognosis hopeless. It is,
therefore, quite unnecessary to discuss the matter further.
=Acute traumatic abscess.= Acute traumatic abscess of the brain most
commonly arises in connexion with an infected compound fracture of the
skull. In the event of laceration of the dura mater, infective organisms
have a ready means of access both to the meninges and to the brain
itself, meningitis or cerebritis resulting. This liability to meningeal
and brain infection is increased when hair, portions of clothing,
bullets, or other foreign bodies are embedded amongst the comminuted
fragments of bone, or driven into the brain substance. In the event of
the dura mater remaining intact, meningitis or cerebritis may still
develop if, as the result of scalp suppuration, the diploic vessels
become thrombosed and plugged with bacteria, some of which may be
carried inwards by the reversed blood-stream, and perhaps by lymphatic
connexions.
The infection may remain localized to the adjacent brain substance, an
acute traumatic cerebral abscess resulting, or may become more widely
diffused--diffuse cerebritis--a condition usually associated with
general meningeal infection.
An acute traumatic cerebral abscess is almost necessarily situated
immediately beneath the site of osseous and membranous lesion, being, in
fact, more a meningo-cortical abscess than a brain abscess proper. The
boundaries are but ill-defined, the walls ragged, and the contents of a
brown-red colour. The surrounding brain is in a condition of red
softening, that is to say, extensively infiltrated with leucocytes, the
vessels thrombosed and teeming with bacteria, whilst minute
extravasations of blood lead to the characteristic colour both of the
contents of the abscess and of the surrounding tissue.
In the more chronic cases, the surrounding area shows some attempt at
repair, dense armies of leucocytes barring the way to the spread of the
infection, and, in the more favourable cases, allowing of the formation
of a definite fibrous barrier.
=Symptomatology.= The symptoms resulting from an acute traumatic
cerebral abscess are largely dependent on the site of the abscess. In
the earlier stages of development suspicion may be aroused by the
presence of persistent headache--frequently localized to the region
primarily affected--by mental and bodily irritability, restlessness, and
pyrexia. All these symptoms may, however, be produced by the unhealthy
condition of the scalp-wound--free suppuration, bare bone, and
extra-dural suppuration.
On or about the third day, the condition of the patient becomes more
grave, the change for the worse being usually of rapid development, and
preceded by severe rigors and general convulsions. The patient shows
further signs of mental irritation, being delirious, restless, and
occasionally actually maniacal.
The temperature is high and rigors are frequent. The pulse is small and
rapid, the respiration increased in frequency, irregular, and often
partaking of the Cheyne-Stokes type. The face is livid, the skin hot and
burning. Vaso-motor disturbance is evidenced by profuse sweating and
well-marked _tache cérébrale_.
=Prognosis and treatment.= The prognosis is almost hopeless unless
radical measures are adopted in the early stages. The scalp-wound should
be enlarged and comminuted fragments of bone removed, or the skull
trephined over the region of the suspected abscess. The lacerated dura
mater is freely opened up and the surface of the brain exposed. Purulent
material is gently removed, and the wound closed in such a manner as to
allow of free drainage.
Even under the most favourable local conditions the prognosis is bad.
=Chronic abscess.= As a preliminary statement it must be pointed out
that breaking down new growths, softening gummata, caseating tuberculous
masses, actinomycotic and hydatid cysts, are regarded in the light of
tumour formation and are discussed elsewhere.
Of 52 cases of brain abscess admitted of recent years into St.
Bartholomew’s Hospital, 41 partook of the chronic type, 30 being
dependent on otitic disease, 3 on frontal sinus suppuration, 5 resulting
from lung disease, and 2 of uncertain origin. The 11 acute cases were
either traumatic or pyæmic.
From these and other statistics it may be regarded as generally accepted
that the majority of brain abscesses are secondary to chronic disease of
neighbouring bone, and more especially middle ear disease. This being
the case, it might naturally be inferred--on anatomical grounds--that
the temporo-sphenoidal lobe of the cerebrum and the cerebellum are more
liable to infection than any other part of the brain. From 100 cases
treated at my hospital the temporo-sphenoidal lobe and cerebellum were
involved in the proportion of about 2 to 1. Körner,[52] reporting on
another 100 cases, gives the following data:--
Abscess of the cerebrum 62 cases
„ „ cerebellum 32 „
„ in both situations 6 „
Hunter Tod,[53] reporting on 100 cases treated at the London Hospital,
found that in children under 10 years of age temporo-sphenoidal abscess
occurred in 87 per cent. cases, and cerebellar in 13 per cent., whereas
in adults cerebral abscess occurred in 65 per cent. and cerebellar in
35 per cent. The development of temporo-sphenoidal and cerebellar
abscesses in the same case was observed in 5 per cent. cases.
=Pathology.= Insomuch as chronic middle ear disease forms the main
predisposing factor in the development of abscess of the brain, the
pathology of brain abscess in general may be considered by discussing
the main features peculiar to otitic abscess in particular.
As the result of chronic middle ear disease, the mucous lining of the
middle ear and its accessory cavities becomes destroyed, the antrum
filled with cholesteatomata, and the middle and external ears with
granulations. The discharge of pus, previously free, is obstructed,
partial or complete blockage occurring. The destruction of the mucous
lining allows of invasion of the surrounding bone, the veins become
thrombosed and filled with bacteria, and the cancellous spaces blocked
with granulations. Further erosion of the bone results, both in the
upward direction towards the tegmen tympani and in the backward towards
the lateral sinus groove and cerebellum. The veins of the tegmen
communicate freely with those of the temporo-sphenoidal lobe, whilst
those ramifying in the mastoid region either communicate with the
lateral sinus itself or with the anterior cerebellar venous system.
Infection may therefore spread (1) _upwards_ to the temporo-sphenoidal
lobe, or (2) _backwards_ to the lateral sinus and cerebellum. In the
former case, meningitis or temporo-sphenoidal abscess develops: in the
latter instance, meningitis, lateral sinus thrombosis, or cerebellar
abscess.
For the formation of a brain abscess it is, of course, essential that
the brain membranes overlying the main site of osseous erosion should be
sealed off in such a manner as to prevent a general infection of the
meningeal region, the dura becoming adherent to the eroded tegmen, &c.
It is œdematous and throws out granulations, both on its parietal and
visceral aspects. The parietal granulations aid in the further erosion
of the bone, whilst the visceral may, according to Macewen,[54] even
indent the brain. By means of thrombosed veins, perivascular lymphatics,
and minute arterioles, a channel of infection is now opened up between
the site of osseous erosion and the temporo-sphenoidal and cerebellar
lobes.
[Illustration: FIG. 74A. DIAGRAM TO SHOW EXTENSION OF DISEASE FROM
TYMPANIC CAVITY, IN MIDDLE EAR SUPPURATION. 1, Perforation through
tympanic membrane; 3, Perforation through Shrapnell’s membrane; 4,
Fistula through outer wall of attic (roof of external meatus); 5_a_,
Extradural abscess; 5_b_, Meningitis; 5_c_, Temporo-sphenoidal abscess;
6, Bulb of jugular (thrombosis); 11, Internal ear; 12, 12_a_, 13, Route
of infection through internal ear giving rise to extradural abscess,
meningitis, and cerebellar abscess. (After Hunter Tod.)]
[Illustration: FIG. 74B. DIAGRAM TO SHOW SURGICAL ANATOMY FOR OPERATIONS
FOR OTITIC INTRACRANIAL LESIONS. 1, Attic; 2, Antrum; 3, Point for
opening temporo-sphenoidal abscess (just above and along the tegmen
tympani); 4, External semicircular canal; 5, Lateral sinus; also shows
area of bone removed in mastoid operation; 6, Bulb of jugular vein; 7,
Facial nerve; 8, Point for opening cerebellum behind lateral sinus; 9,
Point for opening cerebellum in front of lateral sinus (between sinus
behind and external semicircular canal in front). (After Hunter Tod.)]
In any case the abscess usually develops in the white substance of the
brain, just beneath the grey matter, and in close relation to the
primary source of infection.
_The wall of the abscess._ In an abscess of rapid development the walls
are ragged and but ill-defined from the surrounding brain substance. In
the more chronic cases the cavity is shut off from the brain by a
capsule of varying density--usually not more than one-sixteenth of an
inch in thickness, but occasionally of much greater development (see
Fig. 86A). Sometimes--more especially in cerebellar cases--two cavities
may be superimposed, the two abscesses communicating with one another by
means of a narrow, and often tortuous, channel. Successful drainage of
the one cavity may be inadequate to drain its companion. This two-saced
abscess will be again alluded to at a later period.
_Contents of the abscess._ The pus is usually of a greenish hue,
odourless, and acid in reaction. Though often sterile the following
bacteria may be cultivated--_staphylococcus pyogenes aureus_ and
_albus_, _pneumococcus_, _bacillus pyocyaneus_, and the _streptococcus
pyogenes_. The pus is usually of such viscidity that it cannot be
evacuated through the lumen of an ordinary aspirating needle.
_The size of the abscess._ In size the abscess varies greatly, seldom,
however, containing more than 5 or 6 drachms of pus.
_The neck of the abscess._ It was first pointed out by Ballance[55] that
most brain abscesses secondary to disease of the bones of the skull are
‘mushroom-shaped’, the narrow portion or stem being attached to the dura
mater at the original site of infection. The stalked form of abscess is
‘quite comparable, as to its mode of formation, to the superficial
cervical abscess connected by a narrow track to a focus of disease
beneath the deep fascia’.
_Course pursued by an untreated brain abscess._ The abscess enlarges at
the expense of the surrounding tissues, either bursting into the
ventricles of the brain or coming to the surface, there rupturing and
leading to a diffuse meningeal infection. Some few cases have been
reported in which the abscess has established a more or less efficient
natural means of drainage, either along the ‘stalk’ of the abscess or by
means of a new channel to the exterior. In one or two cases,
spontaneous recovery has apparently taken place.
_Mode of healing after successful operation._ Previous to successful
evacuation, the brain immediately surrounding the abscess cavity is
compressed and anæmic. As soon as drainage is supplied, it swells out
like a sponge, more or less obliterating the cavity. The closure of a
cavity by means of the formation of granulation tissue probably never
occurs, and, if the falling together of the surrounding brain is
insufficient to obliterate the cavity, final closure is completed by the
in-dragging of the overlying tissues--scalp, membranes, and brain
becoming intimately fused together.
=Symptomatology.= The symptoms must be considered under the following
headings:--
The symptoms peculiar to the INITIAL stage of the abscess
„ „ „ „ LATENT „ „ „
„ „ „ „ MANIFEST „ „ „
„ „ „ „ TERMINAL „ „ „
=The INITIAL stage.= If a patient suffering from brain abscess is
capable of answering questions, it will usually be found that he dates
his illness from some particular day when he was sick, experienced a
shivering attack, or suffered from a severe attack of headache. Further
inquiry, however, will almost always elucidate the fact that, for some
days or weeks previously, he was not feeling well, suffering from
insomnia and loss of appetite, and experiencing occasional attacks of
headache. Friends and relatives may volunteer information as to general
irritability, alteration of manner, incapability of mental
concentration, and worry over family and financial matters.
At this stage the headache is commonly referred to the frontal region,
less frequently localized to the region of the brain involved. The
patient sleeps badly, and there is often a slight rise of temperature
towards the evening. Occasionally he may vomit, independently of the
ingestion of food.
=The LATENT stage.= Mental depression becomes more marked, headache is
more persistent and now shows a definite tendency to localization, food
is distasteful, and bodily wasting becomes evident. The evening rise of
temperature becomes more constant, sickness more frequent, and vertigo
and giddiness may be noticeable features.
=The MANIFEST stage.= The symptoms arising during the manifest stage
must be considered as follows:--
(_a_) Symptoms dependent on the general increase in the intracranial
pressure.
(_b_) Symptoms dependent on the localization of the abscess.
_Symptoms pointing to a general increase of intracranial pressure_
=General mental condition.= In the latent and early manifest stages the
patient will answer questions more or less correctly, but with
hesitation--as if from delayed comprehension and from prolongation of
the latent period. Answers are often inappropriate to the question, and
given with some confusion of mind and thought--the state of
‘slow-cerebration’.
The patient either lies listless and apathetic--mentally dulled--or
exhibits general irritability, lying curled up in bed, intolerant of all
interrogation and examination. More rarely, cerebral irritation
progresses to actual mania, the patient tossing about in bed, muttering
and delirious. Forcible restraint is often required. In the later
manifest stages the patient lies comatose.
=Headache.= Headache is an almost constant feature, varying greatly in
intensity, but often so severe that the patient is incapacitated from
all attempts at conversation and movement. Exacerbations are frequent,
the sufferer crying out in his agony. The pain may be localized or
diffuse. Localization of the pain to some special region is of
considerable aid to the regional diagnosis of the abscess--more
especially so when it is accentuated by palpation and percussion over
the suspected region.
=Vomiting.= Vomiting is another frequent symptom, probably dependent on
stimulation of the medullary vomiting centre. It is of the so-called
‘cerebral’ type, bearing no relation to the ingestion of food and
unaccompanied by previous nausea and retching. The vomited material is
propelled outwards with considerable force. There appears to be some
relation between the exacerbations of headache and the time at which
vomiting occurs. Vomiting is most constantly observed when the abscess
is subtentorial in position.
=Optic neuritis.= It is exceedingly difficult to determine the frequency
with which optic neuritis develops in cases of brain abscess. Much
depends on the site of the abscess and the duration of its existence.
Optic neuritis is seldom absent in the more chronic cases and is most
constant when the purulent collection is subtentorial in position. The
non-appearance of optic neuritis--even in chronic cases--does not
confute a diagnosis of abscess formation.
When once present, the swelling of the disk may increase rapidly. In a
case of cerebellar abscess recently under my care the swelling reached
6D. in three days. Whatever the localizing value of unilateral neuritis
in tumour formation (see p. 216), I am strongly of opinion that in the
cases under discussion, optic neuritis, when confined to or more marked
on the one side, implies that the abscess is situated on that side.
=The pulse and temperature.= It is commonly stated that, in typical
cases of brain abscess, the pulse-rate is slowed--40 to 60 per
minute--and that the temperature is subnormal. Slowing of the pulse
results from stimulation of the medullary centre, the lowering of
temperature to less determinate causes. In the consideration of pulse
and temperature--and the two must invariably be considered together--it
will, however, frequently be found that the temperature is raised and
the pulse-rate but little altered. Thus, in one case the pulse was 88
and the temperature 103·4 degrees, in another the pulse was 74 and the
temperature 102, in a third case the pulse was 89 and the temperature
102·8 degrees. These cases are very significant, and show that the
greatest attention should be paid to a comparison between pulse-rate and
temperature, a _relative_ slowing of the pulse being more constant than
an actual retardation.
The elevation of temperature results from the fact that the great
majority of cases of brain abscess are secondary to some highly
infective purulent collection, as, for instance, a mastoid empyema. In
such a case, if the mastoid region be cleared out, the temperature will
fall and the typical clinical picture of subnormal temperature and
slowed pulse-rate will be depicted.
=The respiration.= The increase of intracranial pressure may lead to
some slowing and deepening of respiration. Irregularity is, however, the
more common condition, deepening, in the later stages, to definite
Cheyne-Stokes respiration. Under anæsthesia--more especially in
cerebellar cases--there is considerable risk of respiratory failure (see
foot-note, p. 238).
=Vaso-motor changes.= Vaso-motor changes are fairly constant, evidenced
by sweats and flushings, _tache cérébrale_, &c.
=Reflexes.= In the earlier stages of the trouble the reflexes may be
increased and Babinski’s sign present. In the later stages, all reflexes
are abolished.
[Illustration: FIG. 75. A LARGE RIGHT-SIDED TEMPORO-SPHENOIDAL ABSCESS.]
=Other more general symptoms.= Obstinate constipation, foul tongue and
breath, anorexia, deficient urine, loss of bladder and rectal control,
are all noticeable features. A well-marked leucocytosis is generally to
be observed.
_Symptoms dependent on the localization of the abscess_
(_a_) =Temporo-sphenoidal abscess.= The abscess occupies one of the
so-called ‘silent’ areas of the brain, an area merely exercising a
word-hearing faculty (see p. 163). Insomuch, however, as auditory power
is already impaired or lost from the disease existent in the middle ear,
it follows that a temporo-sphenoidal abscess may not give rise to any
localizing symptoms whatever. Definite motor symptoms will only be
observed when an abscess of considerable size exercises an upward
pressure on the lower motor areas, or an inward pressure on the internal
capsule. Thus, (1) when the pressure effects are exercised in the
_upward_ direction the lower motor areas will suffer with resultant
paresis or paralysis of the muscles of the contra-lateral face and upper
extremity, and, if the abscess be situated on the left side, aphasia may
also be present. And (2) when the pressure is exerted mainly in the
_inward_ direction so as to interfere with the internal capsule the
motor areas are affected in the reverse order, lower extremity first and
face last.
[Illustration: FIG. 76. TO ILLUSTRATE THE PRESSURE EFFECTS OF A
TEMPORO-SPHENOIDAL ABSCESS:--(1) _upward_ pressure on the lower cortical
motor area, and (2) _inward_ pressure on the internal capsule. T.S.,
Temporo-sphenoidal abscess; _a._, Cortical area for lower extremity;
_b._, Cortical area for upper extremity; _c._, Cortical area for face;
C.N., Caudate nucleus; L.N., Lenticular nucleus; I.C., Internal capsule;
O.T., Optic thalamus.]
_Aphasia_ will partake of the motor or sensory type according to the
situation of the abscess. Thus, motor aphasia indicates pressure on
Broca’s area, sensory points to the involvement of the region of the
angular gyrus (see p. 163). According to Schmiegelow, some type of
aphasia was present in 23 out of 54 cases of otitic temporo-sphenoidal
abscess.
_Facial paralysis_, whether due to inward or upward pressure, is of the
incomplete or cortical type, the upper face-muscles escaping or being
but slightly affected. No difficulty need be experienced in
differentiating between the ipso-lateral paralysis which results from
destruction of the facial nerve in the aqueductus Fallopii and the
contra-lateral palsy dependent on the cortical lesion.
Pressure may also be exercised on the post-Rolandic sensory areas and on
the tracts that evolve therefrom, but the general condition of the
patient seldom allows of any accurate diagnosis with respect to sensory
involvement in general.
When the abscess is of considerable size, both _third_ and _sixth_
nerves may be involved. For instance, the third nerve, emerging from the
brain at the anterior border of the pons, and passing along the inner
border of the temporo-sphenoidal lobe, is liable to irritation or
pressure paralysis. In the former case, the pupil on the affected side
will be contracted, in the latter instance dilated. When _ipso-lateral_
third nerve paralysis coexists with paralysis of the opposite face and
upper extremity, a condition of crossed paralysis results.
When the sixth nerve is involved the external rectus on the side of the
lesion is paralyzed with resultant internal squint. Conjugate deviation
of the eyes towards the side opposite to the lesion and secondary
lateral nystagmus have both been observed.
Further assistance in the localization may be obtained by careful
observation as to the position of the headache, by palpation and
percussion of the skull, and by a comparison of the intensity of optic
neuritis in the two disks.
(_b_) =Cerebellar abscess.= Many of the symptoms previously described
when dealing with brain abscess in general are intensified when the
focus of suppuration is situated in the confined space beneath the
tentorium cerebelli. Thus, headache is exceptionally severe and more or
less localized to the occipital and cerebellar regions. Again, optic
neuritis may develop rapidly and reach a high grade of intensity,
vomiting is early in onset and of frequent occurrence, whilst certain
other symptoms dependent on the increased intracranial pressure--slowing
of the pulse, alterations in respiratory rhythm--are correspondingly
accentuated.
The more typical _localizing_ symptoms are as follows:--
_Vertigo_ is a prominent symptom, most evident on sudden alteration of
position on the part of the patient. He complains, for instance, of
great giddiness on sitting up in bed. The sensation of movement may be
of self or of objects.
[Illustration: FIG. 77. A CEREBELLAR ABSCESS.]
When standing, he tends, when unsupported, to fall or lurch in some
particular direction, more commonly, in my experience, towards that side
on which the abscess is situated. On this point, however, there is some
difference of opinion and, by itself, it cannot be accepted as having
any great localizing value.
In some rare cases Dana’s symptom may be noticed--a sudden unexpected
attack of vertigo, roaring in the head, relaxation of limbs, and falling
to the ground in an unconscious state. This symptom is said to be almost
pathognomonic of an abscess (or tumour) situated in the region of the
cerebello-pontine angle.
The _cerebellar gait_ can of course only be demonstrated when the
patient is in a fit condition to walk. He shows, by the position of the
feet, a desire to obtain a wide base of support and staggers on, in his
desire to carry out his instructions, usually inclining towards the side
on which the lesion is situated. This inclination is probably dependent
on the weakness of the muscles of the ipso-lateral side (see below).
Another important feature may be observed in the tendency on the part of
the patient to turn the head in such a way that he faces somewhat in the
opposite direction, the chin being directed towards the opposite
shoulder.
_Disturbances of co-ordination_ may be demonstrated by telling the
patient to touch the tip of his nose with his finger, or to strike at an
object held a foot or two in front of him. Such attempts are
characterized by uncertainty and irregularity of movement, accompanied
by considerable tremor.
_Paresis or paralysis of the limbs on the ipso-lateral side._ The
abscess usually occupies the antero-external aspect of the lateral lobe
of the cerebellum, and is so situated that no direct pressure is
exercised on the pyramidal fibres. Some weakness--perhaps paralysis--of
the muscles of the extremities on the same side as the lesion can,
however, usually be demonstrated. According to Luciani, this is
explained in the following manner:--between the cortex of the one side
and the cerebellum of the other there are certain ‘associated’ fibres,
the strength of the impulses sent out from the cortex depending in part
on the integrity of these reinforcing cerebellar fibres. In cases of
cerebellar abscess these reinforcements are cut off with consequent
paresis, or even paralysis, of the muscles of the face, arm, and leg on
the same side as the lesion. Associated with this muscular weakness
there is usually some increase in the deep reflexes. Some of the
pyramidal fibres do not decussate, and, consequently, an ipso-lateral
paralysis may be associated with a contra-lateral paresis.
The same lessening of cortical impulses accounts for a weakening in the
external rectus of the same side, which muscle, acting with the internal
rectus of the sound side, allows of a conjugate deviation of the eyes
towards the opposite side, with well-marked _nystagmus_--of a coarse
type--on attempting to correct this deviation.
[Illustration: FIG. 78. A DIAGRAMMATIC ILLUSTRATION (AFTER LUCIANI) TO
EXPLAIN THE SYMPTOMS OBSERVED IN CEREBELLAR ABSCESS FORMATION. P.,
Pyramidal fibres; C.A., Right cerebellar abscess; R., Reinforcing fibres
from right cerebellum to left cortex; B.g., Basal ganglia; E.R.,
External rectus; N., Nucleus for sixth nerve; D.P.T., Direct pyramidal
tract; C.P.T., Crossed pyramidal tract.]
_Retraction of the head and neck._ Retraction of the head and neck,
stiffness of the nuchal muscles, and even opisthotonos, may be
observed. The existence of these symptoms is always suggestive of
meningeal infection, but an abscess of considerable size, even when
situated in the anterior part of the lateral lobe of the cerebellum, may
so exercise pressure in the downward direction as to cork up that part
of the cerebellum which normally extends into the mouth of the foramen
magnum. The neighbouring upper cervical nerves may then be irritated or
compressed.
_Yawning._ Frequent purposeless yawning is said to be pathognomonic of
cerebellar disease (see p. 165).
_Attitude in bed._ More commonly the patient lies curled up in bed in
the position of cerebral irritation, perhaps more frequently with the
sound side upwards.
(_c_) =Frontal abscess.= The abscess is usually dependent on
long-continued suppuration in the frontal sinus, with deficient drainage
and spread of disease to the surrounding bone. The abscess may be
situated in close relation to the focus of the disease, but, more
commonly, it occupies a more posterior position, so much so that direct
pressure is exercised on the corona radiata proceeding from the
pre-Rolandic or motor area. It would appear also that definite
localizing symptoms do not arise until the abscess has attained
considerable size. The _general symptoms_ peculiar to all cases of brain
abscess are perhaps less definite when the abscess is frontal in
position. Thus, although headache may be localized to the frontal
region, and although optic neuritis may be present, yet vomiting,
alterations in pulse-rate and in respiratory rhythm are less marked than
usual.
The _localizing symptoms_ are often reasonably definite, so much so that
but little difficulty may be experienced in arriving at a diagnosis.
In the earlier stages of the abscess formation motor irritation may
predominate, with the development of _fits of the Jacksonian type_, the
lower and more anterior motor areas being first and mainly affected.
More commonly, however, attention will be directed towards the nature of
the trouble by _paresis or paralysis of the opposite side of the body_.
In this case also the lower motor areas--those responsible for the
opposite side of the face and upper extremity (also the motor
speech-area on the left side of the brain)--are first and chiefly
involved. In some cases--more especially when the abscess is of
considerable size--definite hemiplegia may result.
In cases of frontal abscess, the _mental condition_ of the patient
demands special consideration. Some definite degree of moral perversion
will usually be noticed, the patient--presuming that he is in a
conscious condition--making himself as objectionable as possible. He
will upset his food, disarrange his bedclothes, disobey orders, and even
pass his urine and fæces in his bed though well aware of his
wrong-doing. When questioned he answers with suspicion, when examined he
demands to know the why and the wherefore of the various details of the
investigation. An ophthalmoscopic examination is especially difficult to
carry out in a satisfactory manner. In a case recently under my
care--one in which a frontal abscess was drained three times before a
cure was obtained--these curious mental perversions were observed each
time, and the patient subsequently acknowledged that he had performed
the various acts wittingly, but was unable to deny himself the
opportunity of irritating those around him.
It has been stated that these mental changes are only to be observed
when the abscess involves the _left_ frontal lobe. In my own experience
no such lateral differentiation has been noticed.
_Anosmia_ may be present if the patient is in a condition to respond to
the tests requisite to prove the defect. In most cases, however,
considerable difficulty will be experienced in applying the tests, and
the results obtained are too variable. Anosmia will be associated with
impaired power of taste.
_Pupillary changes._ ‘If the abscess is of large size, the pupil on the
same side is in a state of stabile mydriasis; if small, it may be
sluggish and contracted.’[56]
=The TERMINAL stage.= In _fatal_ cases death results from the pressure
exercised by the expanding abscess on the bulbar centres, or from the
bursting of the abscess into the ventricular or meningeal spaces. During
this terminal stage the pulse becomes very rapid, the respiration
irregular and Cheyne-Stokes in character, whilst the temperature rises
rapidly, reaching 105-110 degrees F. Invasion of the lateral ventricle
is evidenced by violent convulsions, rigidity of the extremities,
opisthotonos, retraction of the head, trepidation, and prostration. The
pupils become widely dilated, and remain in that condition till death
ensues.
=Treatment.= In the operative treatment of _otitic temporo-sphenoidal
and cerebellar abscess_ two courses are available:--(1) to trephine
directly over the abscess through the squamous or cerebellar regions,
postponing mastoid exploration till a later date (the two-stage
operation); and (2) to carry out the complete mastoid operation,
searching for the ‘stalk’ of the abscess, and draining the abscess into
the now-united middle ear and antrum (the one-stage operation).
The former course is advocated by many general surgeons, the latter is
the one usually pursued by the aural surgeon. The advantages claimed for
the former method--the direct trephining method--are as follows:--
(1) The general condition of the patient is often of so serious a nature
as to prohibit the more prolonged procedures essential to the mastoid
exploration.
(2) When the exploration is conducted from the infected middle ear, an
unsuccessful attempt to find the abscess carries with it an appreciable
risk of meningeal and brain infection. Unsuccessful exploration through
the ‘clean’ squamous and cerebellar regions presents no such
disadvantages.
(3) The drainage as supplied through the trephine hole is often superior
to that provided by dilating up the ‘stalk’ of the abscess into the
middle ear.
(4) Many general surgeons do not possess that intimate acquaintance with
the anatomy of the ear which is necessary to carry out a complicated
aural operation.
Each case must be considered on its own merits, but I am inclined to
advocate the two-stage method when the diagnosis is reasonably clear
that the patient is suffering from temporo-sphenoidal or cerebellar
abscess, mastoid exploration being carried out as soon as the patient
has recovered from the first operation. When, however, considerable
doubt exists as to the position of the abscess--or the nature of the
complication in general--it is then advisable to start by exploration of
the mastoid and aural regions, further measures being adopted according
to the conditions found at the time of operation.
1. The two-stage operation.
_Trephining for temporo-sphenoidal abscess._ A point is chosen on the
scalp which lies between 1¹⁄₂ and 2 inches above the centre of the
external auditory meatus, and a bradawl is there introduced so as to
indent the external table of the skull. A small scalp-flap is framed,
one presenting an upward convexity, and all bleeding controlled. The pin
of the trephine is applied to the spot previously indicated on the bone
and the disk removed. On account of the absence of diploic tissue and
consequent approximation of the two tables of the skull, care must be
taken to avoid injury to the posterior branch of the middle meningeal
artery and to the bulging dura mater.
[Illustration: FIG. 79. THE EXPOSURE OF A TEMPORO-SPHENOIDAL ABSCESS.]
The dura is then inspected and palpated; absence of pulsation, loss of
lustre and tenseness, indicate the probable adjacency of the abscess
cavity. The membrane should be crucially incised, all meningeal vessels
that cross the line proposed for section being first under-run on either
side of that line. The scalpel is lightly applied to the membrane and,
as soon as the pia-arachnoid is exposed, the section completed with the
blunt-pointed scissors.
The four dural flaps are turned aside and the cortex exposed. At the
very apex of the bulging brain, and avoiding all visible vessels, a
large blunt-pointed trocar and cannula or, preferably, Horsley’s
pus-evacuator is introduced and passed, for not more than 1¹⁄₂ inches,
in a direction inwards and slightly forwards, parallel to the roof of
the middle ear. The blades of the evacuator must be opened ‘once for
each quarter of an inch of brain substance penetrated’ (Macewen). If the
trocar and cannula be utilized, similar precautions must be adopted.
In the event of failure to find pus at the first attempt, the evacuator
is withdrawn, introduced at the same site, but now passed in other
directions--directly inwards, slightly upwards, and finally, slightly
backwards, in each case for not more than 1¹⁄₂ inches.
By wide separation of the blades of the evacuator the pus is allowed to
escape, to be immediately wiped away by the assistant. Irrigation of the
cavity should never be attempted, not so much because of the
difficulties attendant on that process, but because of the danger of
infecting the neighbouring meningeal regions.
Previous to withdrawal of the evacuator, a small rubber or cigarette
drainage-tube is introduced, projecting into the abscess cavity at the
one end, and brought out through the scalp-flap at the other. It is
advisable to stitch the tube in position.
The dural flaps are replaced in their proper position, but no attempt is
made at sewing them together. The scalp-flap is sutured with the aid of
a few salmon-gut stitches and the dressings applied. The tube may be
shortened daily, and dispensed with after seven to ten days, according
to the progress of the case.
_Trephining for cerebellar abscess._ The abscess usually occupies the
antero-external aspect of the lateral lobe of the cerebellum. It can be
drained with advantage below the level of the lateral sinus and behind
the posterior border of the mastoid process.
The patient should be in the semi-prone position, the head as forwardly
flexed as the administration of the anæsthetic allows.
The incision starts below the external occipital protuberance, and,
following the line of the occipital crest, curves downwards along the
posterior border of the mastoid process, terminating at the apex of that
prominence. The cutaneo-muscular flap is turned down, every precaution
being taken to diminish hæmorrhage, insomuch as severe bleeding may take
place from occipital vessels, and from the mastoid and other emissary
veins. Hæmorrhage from the former source is controlled with forceps,
that from the emissary veins by the introduction of the end of a blunt
probe into the orifice of the foramen. More permanent occlusion can be
obtained by plugging the foramen with catgut, with a sterilized wooden
match, or by means of special ivory, bone, and wooden pegs.
The trephine is applied in such a manner that its circle falls well
below the lower level of the lateral sinus and behind the mastoid
process. After removal of the disk, the dura mater is cautiously opened
by crucial incision and the evacuating instrument introduced, the
cerebellum being explored in the forward and slightly inward
direction--towards the posterior aspect of the petrous bone. The abscess
should be reached within 1¹⁄₂ inches from the opening in the bone. A
drainage tube is introduced, stitched in position, in the manner
described when dealing with temporo-sphenoidal abscess. This tube should
be shortened daily and dispensed with after seven to ten days.
_Trephining for frontal abscess._ An abscess of the frontal lobe is
generally situated so far back, and connected with the source of the
trouble (the frontal sinus) by so long a ‘stalk’ of infection, that
considerable difficulty may be experienced in attempting drainage from
the frontal or nasal regions. Moreover, operations conducted through the
frontal region are apt to result in considerable deformity. The
operation may therefore be conducted with advantage from the
temporo-frontal region. In this situation, the bone is thin, the
operation can be conducted between the split fibres of the temporal
muscle, excellent drainage is supplied, and the scar is inconspicuous.
For a general description of the intermusculo-temporal operation, the
reader is referred to p. 121. In this instance, the field of operation
is shifted further forwards, otherwise the details are very similar. The
skin incision commences above and in front of the external angular
frontal process, curves along the temporal crest, and terminates well in
front of the ear. The temporal fascia is turned down and the muscle
split in the general direction of its fibres, and well retracted on
either side. The trephine is applied, the dura mater incised, and the
abscess evacuated and drained in the manner previously described. The
tube may be removed after seven to ten days.
_The treatment of a chronic encapsuled abscess, wherever situated._ In
attempting to evacuate a chronic encapsuled abscess, both the trocar and
cannula and the evacuator merely impinge against, and tend to push
aside, the dense enclosing wall of the abscess cavity. When such
obstruction is suspected, a director should be introduced in the
direction of the abscess, and the brain explored till the resistance of
the abscess-wall is encountered. With the aid of two narrow spatulæ, or
other suitable instrument, the passage through the brain is gently
enlarged till the wall of the abscess becomes visible. The margins of
the passage through the brain are gently retracted and the abscess-wall
freely incised with the knife. After the evacuation of the pus, a
drainage tube can be introduced, but, as such a method seldom permits of
a permanent cure--the abscess filling up again as soon as the tube is
withdrawn--it is generally advisable to attempt the entire removal of
the abscess-wall. The cut edges of the capsular incision are seized with
narrow-bladed forceps, gentle traction applied, and the surrounding
brain substance carefully peeled away. As a rule, there is no great
difficulty attendant on this process and the hæmorrhage is seldom
severe. The cavity that remains in the brain substance is _lightly_
packed with gauze, this packing being allowed to remain for twenty-four
to thirty-six hours, after which it is withdrawn and a little fresh
gauze introduced, if necessary. The cavity fills up with extraordinary
rapidity, mainly as a result of the expansion and falling together of
the surrounding brain (see Figs. 86 and 86a).
2. The one-stage operation.
_Preliminary exploration of the mastoid operation, followed by an
investigation of the middle and posterior fossæ of the skull._ To expose
the mastoid antrum, the incision commences immediately above and behind
the ear, and, carried down to the bone throughout, terminates near the
tip of the mastoid process. The soft tissues are peeled away in the
forward direction and the cartilaginous ear detached from the posterior
and upper boundaries of the bony auditory meatus.
Macewen’s suprameatal triangle and the supramastoid crest are
identified, the former landmark being taken as a guide to the
communication between the mastoid antrum and the middle ear, the latter
representing the uppermost limit of the field of operation.
[Illustration: FIG. 80. 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. (After Hunter Tod.)]
With the aid of the hammer and chisel the bone is chipped away till the
antrum is exposed--on an average this will be situated about
three-fifths of an inch deep from the surface. The opening necessarily
becomes funnel-shaped, but it should be made as complete as
circumstances permit.
As soon as the antrum is exposed, the seeker or nerve-protector should
be introduced into the aditus, acting as a protector to the underlying
external semicircular canal and facial nerve, and the ‘bridge’ of bone,
which now intervenes between the antrum and the middle ear, chiselled
away, in the manner indicated in Fig. 80.
The field of operation is now carefully cleansed, cholesteatomata,
bone-debris, and ossicles being gently removed, and--with the aid of a
head-lamp--a careful search instituted for fistulous tracts, carious
bone, &c. This search must be carried out with the greatest gentleness
for fear of inducing further complications.
Subsequent procedures vary according to the nature of the conditions
found. Thus:--
1. When the diagnosis is uncertain and when the boundaries of the cavity
appear fairly healthy, the operation may terminate at this point, a
post-meatal flap being formed and the cavity lightly plugged with gauze.
The proximal end of the gauze plug is brought out through the enlarged
auditory meatus and the ear-flap sewn back with a few salmon-gut
sutures.
[Illustration: FIG. 81. EXPLORATION FOR A TEMPORO-SPHENOIDAL ABSCESS. A,
Above the tegmen tympani; B, Through the tegmen tympani. Occasionally
these methods are combined; the bone between the openings being also
removed. (After Hunter Tod.)]
2. When the evidence points to implication of the _middle_ fossa, the
scalp incision is prolonged upwards for about 1 inch and the soft parts
retracted. The supra-tegmental extra-dural space can be exposed either
by chiselling away the osseous roof of antrum and middle ear, or by
means of a separate opening above the level of the supramastoid crest.
In the event of the discovery of an _extra-dural_ collection of pus, the
purulent material is gently wiped away, free drainage supplied, and the
wound closed.
In both this and the preceding case, the progress of the case during the
ensuing twenty-four to forty-eight hours will prove whether adequate
measures have been adopted.
When the symptoms are suggestive of _brain abscess_, when no extra-dural
collection is discovered, and when the dura mater is tense and
discoloured, then it becomes necessary to explore the brain. This can be
carried out through an opening made in the tegmen or above the level of
the supramastoid crest. Which route should be utilized depends on the
local conditions. As a general rule, it is advisable to explore through
the tegmen when a sinus exists in that situation, and above the
supramastoid crest under all other circumstances.
[Illustration: FIG. 82. EXPLORATION FOR A CEREBELLAR ABSCESS. A behind,
and C in front of the lateral sinus; B, Lateral sinus. (After Hunter
Tod.)]
In the latter case, the dura mater is incised crucially and the bulging
brain explored in the manner indicated on p. 266. The mastoid region
should first be cleansed and packed with gauze, but, even with such
precautions, it is obvious that there is some risk of contaminating
membranes and brain in the event of failure to discover the abscess
cavity--an argument in favour of exploring through the ‘clean’ squamous
region (see p. 264).
3. When the evidence points to implication of the _posterior_ fossa, an
incision is carried backwards, from the mid-point of the post-aural
incision, for about 2 inches, and the soft parts retracted upwards and
downwards. With the chisel (or gouge) and hammer, the bone is freely cut
away so as to expose (1) the lateral sinus, and (2) the dura mater below
and behind the curve of the sinus. As soon as the sinus is exposed, the
dura mater may be separated from the bone and the subsinus region
exposed with the aid of craniectomy forceps.
The extra-dural space between the posterior aspect of the petrous bone
and the lateral sinus region is first inspected, and, in the event of
the discovery of a collection of pus, this is gently wiped away and
further exploration postponed till the occasion should prove the
necessity.
When the indications are of such a nature as to demand _exploration of
the cerebellum_, the mastoid region is first cleansed and packed with
gauze, after which the dura mater is incised either in front or behind
the sinus according to the probable situation of the abscess cavity.
After the evacuation of the abscess a drainage tube is stitched in
position in the manner previously indicated.
Difficulties and dangers attendant on the process of trephining for
brain abscess.
_Failure to find the abscess_ is usually dependent on one of the
following causes:--
(_a_) The abscess may be missed if the localizing features are
misleading, if the abscess be small, and if the exploring instrument
be passed in a faulty direction or to an insufficient depth.
(_b_) The abscess may be traversed but not tapped if unsuitable
exploring instruments be used--an aspirating syringe, for instance,
through which the thick pus will not pass. Even when suitable
instruments are used, the attempt to evacuate the abscess may fail if
the operator does not carry out what may be called a system of
progressive exploration, that is to say, if he does not periodically
open the blades of the evacuator (see p. 266).
(_c_) The abscess may be encountered but not penetrated if the surgeon
has to deal with a chronic abscess, the wall of which is merely
pushed aside by the advancing instrument (see chronic abscess of the
brain, p. 268).
_Complications_ arising during and after the evacuation of the abscess
are as follows:--
1. Leaking into the pia-arachnoid and the development of general
meningeal infection.
2. Perforation of the ventricular spaces.
3. Hæmorrhage.
4. Respiratory failure.
5. Osteomyelitis of the neighbouring diploic tissue.
_General meningeal infection_ will bring about a fatal result.
Fortunately, the general rise of intracranial pressure and the
formation of adhesions between the brain and the overlying membranes
tend to prevent its development.
_Perforation of the ventricular spaces_ may occur under two
conditions: (1) when the abscess is associated with internal
hydrocephalus, and (2) when the exploring instrument is passed too
far.
_Hæmorrhage_ is seldom serious when the operation is carried out with
a light hand, all visible vessels being carefully avoided. In the
event of its occurrence, it may be controlled by lightly packing the
cavity with gauze.
_Respiratory failure_ is most liable to occur when the surgeon is
operating for cerebellar abscess. In the event of its occurrence the
surgeon should complete his trephining with the utmost expedition,
thus relieving the intracranial pressure. Under favourable
circumstances, the respiratory rhythm is soon restored. In the more
serious cases, artificial respiration should be attempted whilst the
surgeon carries on his manipulations, opening the skull as rapidly as
possible.
MENINGITIS
Previous to entering into the question of general meningeal infection,
some allusion must be made to the rarer forms of meningitis.
=Serous meningitis.= Quincke demonstrated in 1895 the existence of a
serous form of meningitis, one characterized by a sero-fibrinous
exudate. He showed that, just as we have to deal with a serous or
purulent pleurisy, so we have to consider the possibility of a serous or
purulent form of meningitis.
The exudate appears at first sight to differ but slightly from normal
cerebro-spinal fluid, being clear, yielding the normal chemical
reactions of that fluid, and occupying the subarachnoid region. Later on
it becomes slightly turbid, contains a fair quantity of albumen, and is
proportionately rich in cellular elements--lymphocytes and
polymorphonuclear leucocytes. The membranes are swollen, the vessels
dilated, whilst occasionally many minute hæmorrhages may so allow of the
escape of red blood-corpuscles as to impart to the exudate a
yellowish-red coloration. At a still later stage the exudate becomes
flocculent as a result of the deposition of a fibrinous coagulation, a
gum-like material forming over the surface of the brain.
=Pachymeningitis externa.= Pachymeningitis externa is almost necessarily
dependent on disease of the middle ear, on suppuration in the accessory
sinuses of the nose, and on infected fractures of the vault and base.
The inflammatory changes primarily involve the external aspect of the
dura mater, the external surface of which is injected, roughened with
fibrinous exudate, and, in the more chronic cases, covered with
granulations. In itself the process seldom gives rise to symptoms, but
so soon as the inner surface of the dura shares in the affection
(meningitis), or the infection spreads to the venous sinuses (sinus
thrombosis), or to the brain (brain abscess), definite symptoms arise
pointing to the nature and character of the change.
=Pachymeningitis interna and pachymeningitis interna hæmorrhagica.= As
the direct result of alcoholic excess, of syphilitic infection, and of
trauma, the inner surface of the dura mater loses its shiny appearance,
becomes opaque and thickened, especially in the region of the falx
cerebri and over the convexity of the brain. The sodden and œdematous
condition of the dura gives rise to a fibrinous and membranous exudate,
terminating in the formation of false membranes--one of the factors in
the formation of so-called ‘arachnoid cysts’ (see p. 203). These
membranes are seen to be attached to the dura mater by means of
newly-formed vessels, some of which may rupture, giving origin to blood
exudate sufficing to impart to the membranes a brownish-red coloration.
In the more marked cases, especially in those of a recurrent nature, the
membranes partake of a lamellated type. Occasionally, the hæmorrhages
are more excessive, giving rise to the formation of subdural hæmatomata
from the partial absorption of which the various types of
pachymeningitis hæmorrhagica arise.
These rarer forms of meningitis seldom give rise to such definite
symptoms as to allow the surgeon to carry out surgical procedures in
their earlier stages. Later on, by reason of the development of cystic
accumulations of fluid or other complication, operation may be carried
out with a reasonable degree of success. The operative technique
adapted to the individual case is discussed under appropriate
headings--Jacksonian epilepsy, meningeal cysts, &c.
It is possible that some criticism may be aroused with regard to the
non-inclusion of tuberculous meningitis. Insomuch, however, as I have
operated on a considerable number of cases of tuberculous
meningitis--some intentionally from a decompression point of view,
others by reason of doubtful diagnosis--and have never brought about
more than some temporary alleviation, I have come to regard such cases
as beyond the realms of surgery.
[Illustration: FIG. 83. A FRACTURE OF THE ANTERIOR FOSSA WHICH WAS
FOLLOWED BY THE DEVELOPMENT OF MENINGITIS.]
=Acute lepto-meningitis.= This condition will be considered under the
more familiar, though less correct, designation--_meningitis_.
Attempts have been made to classify the various forms of meningitis on a
bacterial basis. When, however, it is realized that almost any known
form of organism may be present in the exudate, and that the symptoms
dependent on these various infections closely resemble one another,
merely differing in their acuteness and intensity, it would appear that
some other form of classification is preferable.
The following method of classification will suffice:--
=1.= =Meningitis of traumatic origin.= The organisms either obtain
direct entrance to the meningeal space by means of a compound fracture
of the vault or base of the skull, or reach their destination along the
course of the numerous emissary and diploic veins that bring the extra-
and intra-cranial channels into communication.
=2.= =Meningitis secondary to disease of neighbouring regions.=
(1) The accessory sinuses of the nose and ear.
(2) The bones of the skull.
(3) The soft parts--scalp, orbit, nose, and face.
=3.= =Meningitis secondary to disease of more distant regions.= Through
the medium of the blood-stream bacteria may be carried to the meningeal
region in many acute infections--more especially in diseases of the
lung.
=Some anatomical considerations of meningitis.= The _pia_ is closely
applied to the surface of the brain, dipping down into all the fissures,
both major and minor. The _arachnoid_ is only reflected into the greater
fissures--the mesial longitudinal fissure, the fissure of Sylvius,
Rolando, &c. The pia and arachnoid are therefore separated from one
another by a potential space over the convolutions themselves, and by an
actual space in the region of many of the cortical fissures.
On the under aspect of the brain the two membranes are so disposed and
so separated from one another as to form three great basins or cisternæ,
three great spaces acting as a water-bed for the brain. These are the
_cisterna magna_, the arachnoid bridging over the wide interval between
the back part of the under surface of the cerebellum and the medulla,
the _cisterna pontis_, the angular space between the pons, medulla, and
cerebellum, and the _cisterna basalis_, the arachnoid there covering in
the structure situated in the interpeduncular space, including the
Circle of Willis.
The subarachnoid space, both cortical and basal, is traversed by
numerous trabeculæ which, passing from one membrane to the other, break
up the space into innumerable small compartments, all containing
cerebro-spinal fluid and all intercommunicating. The cerebral vessels
ramify in the space, the tributaries being supported by the framework
and bathed in the fluid.
All cranial nerves carry with them in their emergence from the skull a
process of both pia and arachnoid, variable in extent, but so arranged
that the nerve trunk is surrounded for some distance by a funnel-shaped
process of membrane, the cerebral cerebro-spinal fluid being thus
brought into connexion with the cervical lymphatic spaces.
With respect to the origin of the cerebro-spinal fluid and its wave of
flow, the researches of Leonard Hill tend to prove that it is formed
from the lining ependyma and choroid plexuses of the three main
ventricles of the brain, passing thence into the spinal cerebro-spinal
region and, by means of the foramina of Majendie, Key, and
Retzius--apertures in the roof of the fourth ventricle--on to the
surface of the brain. From this latter region there appears to be a
general tendency for the fluid to pass upwards from the basal aspect of
the brain towards the superior longitudinal sinus where it is again
absorbed, probably through the medium of the Pacchionian bodies and
lacunæ laterales of the venous sinus.
[Illustration: FIG. 84. BASAL MENINGITIS SECONDARY TO TEMPORO-SPHENOIDAL
ABSCESS.]
From these few anatomical facts it is manifest (1) that a subarachnoid
purulent effusion has every opportunity of spreading widely over the
surface of the brain, and (2) that inflammation and its results in the
immediate neighbourhood of the roof of the fourth ventricle will tend
to impede the normal flow of cerebro-spinal fluid through the foramina
in that region, thus inducing a degree of internal hydrocephalus
directly proportionate to the degree of obstruction.
Furthermore, it is obvious that the anatomical arrangements are entirely
opposed to the possibility of providing adequate drainage in cases of
general meningeal infection. It has been suggested that trephine holes
should be made on either side of the skull, and that the intervening
meningeal space should be washed out between the two apertures. It is,
however, impossible to attain such a result, not only because of the
futility of attempting to wash through the subarachnoid meshwork, but
also on account of the outward bulging of the brain substance through
the trephine holes and the corking up of those apertures.
The pus rapidly spreads over the surface of the cerebrum and over the
base of the brain, along the sheaths of the emerging cranial nerves, and
down the spinal canal. Associated with vascular dilatation there is
extensive leucocyte extravasation into the perivascular spaces, the
course of the line of the attack being mapped out by white and yellow
lines and areas of exudation. Insomuch, also, as the meningeal vessels
are in direct continuity with those of the cortex itself, it follows
that a well-developed case of meningitis implies a corresponding degree
of cerebritis, with red or white softening of the brain substance
according to the degree of hæmorrhagic extravasation.
=Symptomatology.= Meningitis is generally sudden in onset and ushered in
by a rigor, frequently of a most intense character. Headache is always a
marked feature, commonly diffuse, but sometimes localized to the region
primarily and mainly affected. The headache is intense and exacerbations
are marked, the patient crying out in his agony. There is great mental
irritability and all attempts at clinical examination are strenuously
resisted.
After the initial rigor the temperature remains high, with occasional
remissions during the early hours of the morning. Vomiting may be
frequent and violent, but, according to my observations, this has not
been a conspicuous feature.
The pulse-rate is increased, whilst, in the early stages, the volume is
full and the tension high. The skin is burning hot and dry, except
during the post-rigor periods when sweating predominates.
The face is flushed, often turgid, and the eyes are bright. General
restlessness is a marked feature.
The more _localizing_ features may be arranged in three groups:
intellectual, motor, and sensory.
=Intellectual symptoms.= The condition of the patient is one of great
restlessness, increasing sometimes to actual violence and mania.
Attendants are usually required to restrain his movements, and, tossing
about in bed, crying out in his pain, muttering and wandering in his
delirium, he offers a typical clinical picture of cerebral irritation.
=Motor symptoms.= The motor symptoms vary according to the region mainly
involved, cortex or base. In the _former_ case, excitation results in
twitchings and convulsions of the regions supplied by the cortical areas
involved. Convulsions may be general or confined to a certain group of
muscles, the former condition usually present in children, the latter
more often observed in adults and occasionally partaking of the
Jacksonian type. Convulsions may be associated with contractures of the
limbs, the flexors mainly affected in such a manner that an attitude of
general flexion may be assumed. The patient appears to suffer pain when
attempts are made to straighten the limbs. In any case, such attempts
are resisted.
Implication of the _base of the brain_. This is evidenced by symptoms
sufficiently definite. Thus, the following symptoms may be observed:--
_Optic neuritis._
_Myosis and squints_, from involvement of the third, fourth, and sixth
nerves.
_Trismus_, from implication of the third division of the fifth nerve.
_Facial paralysis_, from implication of the seventh nerve.
_Deafness_, from involvement of the eighth nerve.
_Dysphagia and dyspnœa_, from involvement of the ninth and tenth nerves.
_Rigidity of the neck and torticollis_, from involvement of the eleventh
nerve.
_Retraction of the head and neck_, from involvement of the posterior
divisions of the upper cervical nerves.
_Opisthotonos_, from the involvement of the posterior divisions of the
upper cervical nerves, sometimes of so excessive a nature that the body
is bent backwards to such a degree that the head and heels are almost
brought into contact. More rarely, pleurosthotonos or lateral flexion is
observed.
=Sensory and other phenomena.= Amongst such symptoms may be mentioned
cutaneous hyperæsthesis, photophobia, and vaso-motor changes--the
last-named evidenced by flushings, sweats, and _tâche cérébrale_.
Rapid emaciation, anorexia, and distaste for all nourishment are the
rule, whilst retention of urine, albuminuria, and glycosuria have been
observed.
The reflexes, both deep and superficial, are often increased. Kernig’s
sign is generally present.
=The period of depression.= The acute stage seldom persists more than
two or three days, the period of excitation giving place to that of
depression. The transition is usually of a rapid nature. The depression
stage is dependent on exhaustion of the cortical and basal centres.
The temperature remains high, rising towards the evening and falling a
degree or more in the early hours of the morn. Death usually takes place
when the temperature is at its highest.
The pulse may become slower as the intracranial pressure increases, but,
more commonly, as the result of toxic poisoning, the rate increases
whilst the rhythm becomes irregular and the tension lowered.
Respiration may partake of the Cheyne-Stokes type, whilst the impaired
æration of the blood and the weak action of the heart are evidenced by
cyanosis of the face, œdema of the lower extremities, &c.
Death, primarily due to respiratory failure, is often preceded by
general twitchings or convulsions.
The whole course of the illness seldom lasts more than a week, the more
acute cases terminating within two or three days.
=Treatment.= Whether threatening, developing, or obviously present, the
patient should be treated with urotropin (see p. 116). In its early
stages of development immediate operation affords some hope of cure,
such treatment having as its basis the supply of adequate drainage. The
source of the infection must be removed--so far as circumstances
permit--the dura mater freely incised, and the pia-arachnoid region so
opened up as to allow of the escape of some of the purulent or
semi-purulent fluid. The wound is largely allowed to remain open, packed
with gauze. The predominant organism may be isolated and, if time
allows, suitable vaccine treatment instituted. In the meantime, 20 to 40
cc. of pyogenes serum should be administered.
From the point of view of diagnosis, _lumbar puncture_ should never be
omitted. The fluid escapes at high tension, is turbid and contains many
polymorphonuclear leucocytes and organisms, the latter verified with the
greatest advantage after centrifugalization. Repeated lumbar punctures
are also said to be of some benefit with respect to _treatment_.
SINUS THROMBOSIS
=Lateral sinus thrombosis.= Soon after entering on its course across the
mastoid process the lateral sinus presents a well-marked S-shaped curve.
This sigmoid sinus bulges markedly forwards--especially on the right
side--towards the region of the mastoid cells and antrum, so much so
that a mere shell of bone intervenes between the sinus on the one hand
and the antral region on the other. Indeed, the relations are so
intimate that one would expect a more frequent occurrence of lateral
sinus thrombosis. Furthermore, the sinus receives numerous venous
communications from the mastoid cells, antrum, and other parts of the
temporal bone, conspicuous amongst the last-named group of vessels being
the mastoid emissary vein which, passing inwards at the upper and
posterior border of the mastoid process, connects the posterior
auricular and occipital veins with the lateral sinus.
From these considerations it is obvious that any acute or chronic
infective process originating either in the aural region or in the
neighbourhood can readily infect the sinus by direct propagation of
organisms along one or more of these inter-communicating vessels
(thrombo-phlebitis).
The sinus may also become infected in middle-ear disease by the more
gradual process of mining and sapping, the osseous barrier between the
antrum and sinus being progressively destroyed by the backward progress
of the aural disease. The sinus may erect an additional barrier by
throwing out granulations (external pachymeningitis) against the
invading host, but, in the event of the attack overcoming the defence,
sinus thrombosis may result, at first perhaps of a non-infective type
but soon becoming definitely septic, the clot softening and
disintegrating (osteo-phlebitis).
There can be no question that middle-ear disease is responsible for the
very great majority of cases of lateral sinus thrombosis, and whether
the infection takes place by extension of thrombus along the connecting
veins (thrombo-phlebitis), or after destruction of the osseous barrier
(osteo-thrombosis), the results are more or less identical.
Thrombosis first occurs in that part of the sinus which is in closest
relation to the primary cause of the infection, the clot rapidly
increasing in size until the lumen of the sinus is entirely obliterated.
In its early stages the thrombus is of a chocolate colour, softening at
a later date and breaking down into a purulent material. Many varieties
of bacteria may be present though the infection is mainly dependent on
the presence of the streptococcus pyogenes.
Two changes may now occur:--(1) the central portion of the thrombus,
having softened into a purulent material, may be limited by the firmer
thrombus in front and behind; and (2) the thrombus may extend into the
neighbouring and connecting venous channels _downwards_ along the course
of the internal jugular vein, _backwards_ along the course of the
lateral sinus, _inwards_ along the course of the superior petrosal
sinus, _outwards_ along the line of the mastoid emissary vein,
_downwards_ through the posterior condyloid foramen, and _inwards_ along
meningeal veins.
The =symptomatology= may be considered as follows:--
(1) Symptoms dependent on the extension of the thrombus to neighbouring
venous and lymphatic channels.
(2) Symptoms resulting from toxic absorption or dependent on the
transmission of infected material to other parts of the body.
1. _Symptoms dependent on the extension of the thrombus to neighbouring
venous and lymphatic channels._ When the thrombus spreads downwards
along the course of the _internal jugular vein_, there is swelling and
tenderness along the line of the vein. The vessel, though thrombosed in
its upper part--perhaps throughout its whole extent--is itself seldom
palpable, the cervical swelling usually being dependent on associated
lymphadenitis and lymphangitis. In those few cases where the thrombosed
vein can be felt, resembling a ‘buried lead pencil’, the thrombus is
sometimes of the non-infective type.
The combined venous and lymphatic involvement causes œdema of the
tissues, pain, and rigidity on attempted movement. The anterior and
external jugular veins may become engorged from the extra strain thrown
upon them. Subsequently, the inflamed parts may break down and extensive
cervical suppuration result.
When the thrombus spreads _backwards_ along the course of the _lateral
sinus_, the coagulation process may extend as far as the torcula and
even further. Evidence as to the nature and extent of the process is not
always apparent, though one expects to find some œdema of the overlying
scalp tissues.
When the process spreads _inwards_ along the course of the _superior
petrosal sinus_ there is considerable risk of involvement of the
corresponding cavernous sinus, possibly of the opposite sinus also (see
p. 288).
When the process spreads _outwards_ along the course of the _mastoid
emissary vein_, œdema, and dilatation of veins in the post-auricular
region are observed, associated with tenderness on palpation. This is
most apparent at the upper and posterior border of the mastoid process.
When the thrombus spreads _downwards_ along the course of the _posterior
condyloid vein_, there may be some œdema and pain on pressure in the
upper part of the posterior triangle of the neck, associated with
glandular enlargement in the region. These symptoms are dependent on the
connexion established by the posterior condyloid vein between the
sigmoid sinus and the deep veins of the neck.
When the thrombus extends _inwards_ along the meningeal veins,
meningitis, meningo-cerebritis, and cerebral abscess result.
2. _Symptoms resulting from toxic absorption or dependent on the
transmission of infected material to other parts of the body._
_Optic neuritis_ is present, according to Hunter Tod, in about 50 per
cent. cases. It develops rapidly and attains a high degree of intensity.
_Headache_ is usually intense in character, persistent, but little
remedied by drugs and presenting marked exacerbations. It is often most
acute over the affected region.
The _mental condition_ of the patient is subject to variation. In the
average case mental symptoms are quite disproportionate to the severity
of the disease. Sometimes the patient is cheerful, perhaps rather
excited, retaining his faculties to the last, in other cases--as the
result of excessive toxic poisoning--he lies in a stuporose,
typhoid-like state. When the thrombus is associated with meningitis,
meningeal symptoms predominate.
_Vomiting_ is often a conspicuous feature, generally of the so-called
‘cerebral’ type, a regurgitation without nausea and retching.
The _pulse_ is rapid, the rhythm irregular, and the tension lowered.
The _temperature_. The formation of the thrombus is usually notified by
the advent of one or more severe rigors, the temperature rising to 103°
or more. During the height of the illness the temperature is high but
remittent, and rigors are frequent. The occurrence of a series of rigors
is almost certainly indicative of sinus thrombosis. Any marked remission
of temperature is succeeded by profuse sweating, but, with this
exception, the skin remains dry and burning.
Each rigor implies the extension of the thrombus to other venous
channels or the transference of infected particles, by means of the
blood-stream, to other parts of the body. In the young general
convulsions are often observed.
The tongue is brown and dry, the breath foul and diarrhœa of common
occurrence. The skin may be jaundiced, and septic rashes are prone to
develop. The liver and spleen may be enlarged and tender. Cough and foul
sputum point to pulmonary infarction.
=Treatment.= The mastoid antrum is rapidly exposed and the conditions
investigated. The bone is then chiselled away in the backward direction,
with the hammer and gouge, so as to expose the lateral sinus. The
question then arises as to the condition of the sinus. This is a matter
that may require considerable experience. The surgeon should be guided,
not so much by exploratory puncture as by the surroundings and general
appearance of the sinus. Thus, the absence of bleeding from the mastoid
emissary vein during the process of exposure is very significant of
sinus thrombosis. Again, whilst the normal sinus pulsates, is of dark
blue colour and presents a shining surface, the thrombosed channel may
be covered with pale granulations or obscured by fibrinous deposit, it
does not pulsate, and appears of a yellow or deep purple colour. Between
it and the bone there may be a collection of purulent matter. In the
event of doubt, the surrounding regions should be carefully protected
with gauze, after which the sinus may be punctured with a needle. The
absence of fluid blood is conclusive of thrombosis.
[Illustration: FIG. 85A. DIAGRAM TO SHOW THE USUAL POINTS AT WHICH THE
LATERAL SINUS IS PRIMARILY INFECTED. A, High up; from the posterior
mastoid cells. In this case it may not be necessary to tie the jugular
vein. B, Low down; involving the jugular bulb. This necessitates
ligature of the vein. (After Hunter Tod.)]
[Illustration: FIG. 85B. THE LATERAL SINUS EXPOSED AND OPENED. The lumen
of the sinus is obliterated above and below the region of the infected
thrombus by plugs of ribbon gauze pressed in between the sinus wall and
the overlying bone. In this case it is not necessary to tie the jugular
vein. (After Hunter Tod.)]
In the event of the surgeon concluding that thrombosis is present,
subsequent procedures vary according to the extent of the thrombus.
Thus, _when the clot appears to terminate above the jugular bulb_, a
strip of gauze is inserted between the bone and the parietal wall of the
sinus so as to obliterate the lumen of the sinus on the cardiac side of
the clot.
The danger of further extension of the clot being thus obviated, the
bone is nibbled away in the backward direction till at least half an
inch of healthy vessel is exposed on the occipital side of the thrombus.
A second gauze plug is then introduced so as to obliterate the sinus
lumen in that region also.
In the interval between the two plugs the sinus is freely laid open, all
clot and granulations being gently curetted and washed away. Some
bleeding may take place during these procedures, from the mouths of
certain vessels entering the sinus between the two compressed regions.
This is in itself a favourable symptom, insomuch as it proves that the
thrombotic process has not extended in those directions. This hæmorrhage
may be controlled with gauze plugs. The parietal sinus wall in direct
relation to the thrombus is freely cut away, after which the whole field
is lightly packed with gauze and the ear sewn back into position. The
main portion of the wound is left open, the sinus plugs being brought to
the surface whilst those inserted into the combined middle ear and
antrum emerge from the external auditory meatus.
All gauze-plugs may be withdrawn after twenty-four to thirty-six hours,
the wound cleansed and lightly repacked. This process is continued daily
till all is healed.
_When the clot extends into the jugular bulb, and when the jugular vein
appears to be involved_, it is necessary to expose and ligature the vein
in the neck, thus preventing further extension of coagulation and
diminishing the risk of general infection. This measure should be
carried out before the lateral sinus is laid open. With fresh gloves and
another set of instruments, the vein is exposed so as to allow the
application of two ligatures, and the division of the vessel between
those two ligatures. If possible, the ligatures should be applied above
the level of the entrance of the common facial vein. In all cases,
however, the application must be carried out, if possible, below the
lower limit of the thrombus. After the vein has been divided, the upper
end may be dissected in such a manner as to allow of its being brought
to the surface of the wound and there anchored.
Elsewhere the neck-incision is sewn up and protected with collodion
gauze. The surgeon then returns to the mastoid and sinus regions,
completing the exposure of the sinus and laying it open freely to the
surface. At the termination of these procedures, an attempt may be made,
by irrigation between the open sinus above and jugular vein below, to
wash away all thrombus contained in the intervening portion of the
vessel.
Finally, both sinus and aural regions are packed with gauze, in a manner
similar to that described above. Dressings are reapplied as
circumstances demand, and the wounds allowed to heal by granulation.
The great frequency of a streptococcus pyogenes infection justifies one
in the early administration of anti-streptococcic serum (20 to 40 c.c.
of Burroughs Wellcome’s ‘Pyogenes’) followed by an autogenous vaccine as
soon as that can be prepared.
MAIN POINTS IN THE DIFFERENTIAL DIAGNOSIS BETWEEN
---------------+-----------------+-----------------+------------------
| BRAIN ABSCESS | MENINGITIS | LATERAL SINUS
| | | THROMBOSIS
---------------+-----------------+-----------------+------------------
_Onset_ | Insidious. | Acute. | Acute.
| | |
_Temperature_ |Subnormal (see p.|First a rigor, |First a rigor,
|255). |then high and |then high and
| |continuous |continuous
| |temperature, |temperature,
| |usually |usually remittent.
| |intermittent. |Frequent rigors.
| | |
_Pulse_ |Slow (see p. | Rapid. | Rapid.
|255). | |
| | |
_Mental |Often apathetic. |Very restless and|In the early
condition_ |In the later |delirious. |stages, the mind
|stages, stupor |Sometimes |is clear. This
|and loss of |maniacal. Coma |condition may
|consciousness. |towards the end. |persist till near
| | |the end when
| | |delirium and coma
| | |become evident.
| | |
_Special |Paresis or |Squints, |Œdema over
symptoms_ |paralysis, |retraction of the|mastoid, pain
|according to the |head and neck. |along course of
|site of the |Irregular |internal jugular
|lesion. |palsies. |vein. Enlarged
| | |cervical glands.
| | |
_Blood and |Progressive |Increased |Blood infection
cerebro-spinal |leucocytosis. |leucocyte count |frequent.
examination_ |Increased |and organisms in |
|leucocytes in |fluid withdrawn |
|cerebro-spinal |by lumbar |
|fluid. |puncture. |
---------------+-----------------+-----------------+------------------
In typical cases no great difficulty will be experienced in diagnosing
between brain abscess, meningitis, and lateral sinus thrombosis. In many
cases, however, two or more of these conditions may be co-existent.
Thus, both brain abscess and lateral sinus thrombosis are often
complicated by the presence of a meningeal infection. Again, the undue
prominence of abdominal, cardiac, or pulmonary symptoms--more especially
in cases of lateral sinus thrombosis--demand the full consideration of
enteric fever, endocarditis, and pneumonia. Thus, in a case recently
under my care at the hospital, and in which I had the benefit of the
wide experience of my Aural colleague, Mr. West, operative procedures
were carried out on the mastoid region, the patient dying some days
later from enteric fever. Again, the question of differential diagnosis
between tuberculous meningitis, brain tumour and brain abscess is always
cropping up. Thus, a short time ago, I explored both temporo-sphenoidal
lobes in a boy suffering from double otitis media and presenting
well-marked general cerebral symptoms, only to find that he was a
subject of tuberculous meningitis.
The diagnosis is often difficult, and no trouble must be spared in the
complete investigation of the case. _Lumbar puncture_ should invariably
be carried out, the fluid being examined both cytologically and
bacteriologically. In all cases of doubt one would be wise to call in
further advice before undertaking exploratory operation.
=Cavernous sinus thrombosis.= Thrombosis of the cavernous sinus arises
either as an osteo-phlebitis or as a thrombo-phlebitis. In the former
case, the thrombus is dependent on disease of the bones related to the
sinus--arising more especially as the result of prolonged sphenoidal
sinusitis--whilst, in the latter instance, the sinus becomes infected
through one of the many vascular communications connecting it with other
neighbouring regions. Thus the radicles of the ophthalmic vein, by means
of their communication with orbital, ethmoidal, and upper nasal vessels,
and their connexion at the inner canthus of the eye with radicles of the
angular vein, afford the most ready means of infection. Again, infection
may spread from the auditory region along the superior petrosal sinus,
and from the tonsillar and pharyngeal regions along the various emissary
veins connecting the cavernous sinus on the one hand with the deep
cervical vascular system on the other.
The two cavernous sinuses intercommunicate by means of the circular
sinus, and consequently thrombosis of the one sinus is liable to involve
its fellow. According to Macewen,[57] bilateral trouble occurs in 50 per
cent. cases, the infection often spreading from one sinus to the other
within twenty-four to thirty-six hours.
Thrombosis of the cavernous sinus is often associated with meningeal
infection or brain-abscess.
=Symptomatology.= (_a_) _Symptoms dependent on the formation of the
thrombus and its extension to neighbouring venous and lymphatic
channels._ The presence of the thrombus and its extension into
ophthalmic, angular, and retinal veins leads to proptosis, paresis of
the ocular muscles, disturbances of vision, and œdema. _Proptosis_ is of
rapid development, frequently reaching its maximum within a few hours,
the globe being protruded in the downward and outward direction. With
respect to _ocular palsies_, the movements of the globe are greatly
restricted with squints, ptosis, and perhaps complete ophthalmoplegia.
The pupil may be contracted during the earlier stages, becoming fully
dilated and insensitive at a later date. The _vision_ suffers in
proportion to the degree of paralysis of ocular muscles and associated
retinal hæmorrhages and thrombosis. The veins of the lids, conjunctivæ,
and upper part of the face and forehead are engorged, with corresponding
œdema of the soft parts. The conjunctivæ may be chemotic.
The spread of the thrombus to the opposite sinus results in the
development of bilateral symptoms, whilst the involvement of the
petrosal sinus may bring about thrombosis of the lateral and sigmoid
sinuses, with corresponding developments.
In other cases the meningeal veins are affected at an early date, in
which case the symptoms dependent on the cavernous thrombus are obscured
by those resulting from the meningeal infection.
(_b_) _Symptoms dependent on toxic absorption or resulting from the
transference of infected particles to other parts of the body._ These
more general symptoms closely resemble those enumerated when discussing
lateral sinus thrombosis (see p. 283). Headache, however, is of the most
intense type, and pain, of a severe neuralgic character, is referred
along the course and distribution of the first and second divisions of
the fifth nerve.
=Treatment.= It has been suggested that exploration could be carried
out, the thrombus evacuated, and the cavernous sinus region drained from
the naso-ethmoidal region or by approach along the floor of the middle
fossa of the skull--an exaggerated Gasserian ganglion operation. Both
these methods have been tried, but the difficulties encountered and the
want of success tended to show that cavernous sinus thrombosis was
beyond the reach of the surgeon. However, of recent date, more hopeful
views have been entertained, it being suggested that the globe should be
removed, the sinus explored, and the orbital cavity packed with gauze.
It is doubtful, however, whether the end justifies the means.
=The prognosis in brain abscess, meningitis, and sinus thrombosis.= A
patient may be expected to recover from _brain abscess_, whether
temporo-sphenoidal, cerebellar, or frontal, if an early diagnosis be
made, if the case be uncomplicated by meningeal infection or sinus
thrombosis, and if the evacuation be carried out without any great
difficulty. As Sir William Macewen[58] pointed out, ‘an uncomplicated
brain abscess may be regarded as the most hopeful of all cerebral
affections.’ In fatal cases, death results from general meningeal
infection or from the bursting of the abscess into the lateral
ventricles.
In _meningitis_ the prognosis is bad, more especially when the process
is widespread. Early exposure of the affected region and the supply of
adequate drainage offer the only hope of recovery. This, even under the
most favourable circumstances, is a desperate remedy.
The prognosis in _lateral sinus thrombosis_ hinges to a large extent on
the time at which operative procedures are carried out. When the case is
seen and operated on at an early date in the history of the disease,
recovery may be anticipated in about 50 per cent. cases. Hunter Tod
states that, when all cases are considered of whatever grade, about
one-third recover. Death results from pyæmia, septicæmia, meningitis, or
brain abscess.
_Cavernous sinus thrombosis_ of the infective variety almost necessarily
terminates fatally. Death results from causes similar to those observed
in cases of lateral sinus thrombosis.
HERNIA CEREBRI
The term Hernia cerebri was formerly used as inclusive of all those
conditions in which the brain protruded through some aperture in the
skull, whether such opening was congenital, traumatic, or
post-operative.
Owing to the recent advances in cranio-cerebral surgery, especially with
reference to the frequent adoption of decompression operations, it is
advisable that the cases should be classified into two groups:--
=1. Cases of hernial protrusion=, including cephaloceles (see Chapter
I), protrusions intentionally produced by the surgeon in a decompression
operation, and those which follow after unsuccessful operations for
tumour removal. It will be observed that, in all these cases, the
projecting brain, though bulging through its osseous barrier, is still
protected by a more or less normal scalp-covering.
=2. Cases of hernia cerebri.= Here, as the result of injury to scalp,
bone, dura, and brain, the cerebral substance bulges through a
deficiency in the vault and presents on the surface, uncovered by
integument. Hernia cerebri _can_ develop under non-infective conditions,
the congested state of the bruised or lacerated brain bringing about
that degree of intracranial tension which can only be relieved by the
outward projection of the brain. Still it must be accepted that Hernia
cerebri almost invariably implies some bacterial infection.
_Hernial protrusions_ are dealt with elsewhere. _Hernia cerebri_
requires some consideration. Its development, by reason of its usual
bacterial agency, must always be regarded as of serious import. The
congested brain bulges through the aperture in the skull and presents on
the surface as a purple--sometimes black--fungating mass, bleeding
freely, and associated with a considerable discharge of cerebro-spinal
fluid, serum, and pus.
The effects produced by this condition vary according to the extent of
the cerebritis, and the question of associated meningeal infection.
When associated with meningitis those symptoms which might result from
the hernial protrusion are more or less obscured by those dependent on
the meningeal infection. Under other circumstances, the symptoms vary
according to the extent and position of the area involved. Thus, when
the infection is limited to the surface of the brain in the immediate
vicinity of the aperture in the bone, the patient may merely complain of
some headache and present some symptoms of cerebral irritation. More
usually, the infection spreads rapidly to the surrounding brain
substance, and the patient evidences the most acute stage of cerebral
irritation, passing thence rapidly into a stuporose, typhoid-like
condition.
[Illustration: A
FIG. 86. A CASE OF HERNIA CEREBRI. A, The abscess after removal (natural
size), cut so as to show the thickness of capsule.]
=Treatment.= With the object of reducing the infectivity of the
protruding brain, fomentations have been advocated. From my own
experience, however, it would appear that their application tends to
increase the degree of protrusion, and that better results may be
obtained by keeping the exposed brain as dry as possible, painting over
with a 2¹⁄₂ per cent. solution of iodine in rectified spirit, dusting
with antiseptic powder, and protecting with dry dressings, frequently
replaced.
In the event of failure to improve the condition by means of these minor
remedies--a too-frequent occurrence--excision of the protruding mass may
be regarded as a perfectly justifiable procedure, providing that the
hernia does not include the cerebellum or motor cortical region. The
protrusion is shaved away flush with the level of the skull, the raw
surface of the brain lightly painted with iodine, dusted with iodoform
or other antiseptic powder, and protected with gauze and wool.
The prognosis is necessarily most grave, but the most astounding
recoveries have taken place under this mode of treatment.
[52] _Archiv für Ohrenheilkunde_, vol. xxix, p. 17.
[53] _Diseases of the Ear_, Oxford Medical Publications, p. 257.
[54] _Pyogenic Diseases of the Brain and Spinal Cord._
[55] _Some Points in the Surgery of the Brain_, p. 95.
[56] Macewen, _Pyogenic Diseases of the Brain and Spinal Cord_.
[57] _Pyogenic Diseases of the Brain and Spinal Cord_, p. 247.
[58] _Pyogenic Diseases of the Brain and Spinal Cord._
CHAPTER IX
BULLET-WOUNDS OF THE SKULL AND BRAIN
In the consideration of bullet-wounds of the skull and brain the
following factors must be taken into account:--
The velocity of the bullet.
The distance at which the bullet is fired.
The size of the bullet.
The nature of the bullet.
The angle of impact.
The position of the bullet at the moment of impact.
Before, however, noting the varying effects on the skull as produced by
one or more of these factors, it will be necessary to allude briefly to
the average effect on the skull as produced by bullet-wounds in general.
‘When a foreign body passes through any part of the skull--it matters
not what the direction may be--the aperture of exit is always greater
than the aperture of entry.’ Such was the law enunciated by Teevan in
1864. The explanation is as follows: ‘The aperture of entry is caused by
the penetrating body only, whilst the aperture of exit is larger,
insomuch as it is made by the penetrating body plus the fragments of
bone driven out of the proximal table and diploe.’ It might also be
added that the greater degree of damage will always be incurred by the
unsupported table--the internal at the wound of entry, the external at
that of exit.
The size and shape of the aperture of entry through the external table
bears a close resemblance to the size and shape of the entering bullet.
As a general rule, it is round or oval, and presents clean-cut edges
with some small radiating fissures. The aperture of entry through the
internal table is larger, the margins inverted towards the brain, the
radiating fissures more pronounced, and small fragments of bone
in-driven towards the brain.
In the event of perforation of the skull through the medium of a
high-velocity bullet, the aperture of exit through the internal table
closely resembles that through the external table at the site of entry,
with the exception that it is influenced by any changes in position that
the bullet may have undergone during its transmission through the brain.
The wound of exit through the external table is again greater than that
through the internal--in accordance with Teevan’s law--the margins
everted, the surrounding bone fissured or comminuted, whilst fragments
of bone may be driven out beneath the lacerated scalp, or even blown
completely away. On the other hand, when the bullet is fired at close
range, the aperture of exit is often considerably larger than that of
entry--due, in all probability, to superadded explosive effect.
The effect of the _velocity_ of the bullet on the fracture:--The greater
the velocity of the bullet the greater the resemblance of the wounds of
entry and exit to the size and shape of the bullet, the ‘cleaner’ the
holes, and vice versa.