CHAPTER X

OPERATIONS FOR INTRACRANIAL ABSCESS OF OTITIC ORIGIN

An intracranial abscess, the result of disease of the temporal bone, is usually situated close to the surface of the brain, and is in close relationship with the diseased area of bone through which the infection has taken place. The actual track of the infection can frequently be traced through the bone to the dura mater and brain substance itself; sometimes, indeed, a fistula is found to pass through the bone and to communicate with the intracranial abscess. On the other hand, though rarely, the surface of the bone to all appearances is normal and there are no adhesions between it and the dura mater and underlying brain substance, and the abscess may be situated deeply within the brain.

With regard to the comparative frequency of temporo-sphenoidal and cerebellar abscess, in 100 cases collected from the records of the London Hospital the writer found that in children under ten years of age temporo-sphenoidal abscess occurred in 87% and cerebellar only in 13%, whereas in adults cerebral abscess occurred in 65% and cerebellar in 35%; and that a cerebral and cerebellar abscess occurred together only in 5% of the cases.

These statistics are practically the same as Körner’s (_Die otitischen Erkrankungen des Hirns, der Hirnhäute und der Blutleiter_). Ballance, on the other hand, considers cerebellar abscess a more frequent occurrence than temporo-sphenoidal.

Multiple abscesses may be met with, usually the result of pyæmia.

=Indications.= An intracranial abscess must always be opened and drained.

Indications pointing to such a condition are persistent headache, purposeless vomiting, a slow pulse, a subnormal temperature, and optic neuritis. With this there is usually some change in the mental condition, especially in the case of a temporo-sphenoidal abscess. In the early stages there may be attacks of simple forgetfulness or mental aberration, or, on the other hand, that of extreme mental excitement. Owing to the intracranial pressure caused by the increase in size of the abscess, the mental state becomes impaired and the condition known as slow cerebration or the ‘dream state’ may be observed.

It must, however, not be forgotten that the same clinical picture may be produced by other conditions, such as an intracranial tumour: in the case of a middle-ear suppuration, however, an intracranial abscess may be diagnosed unless this can otherwise be excluded.

Before operation is decided on, the site of the lesion must be determined. This can only be done if certain localizing symptoms are present.

_In a temporo-sphenoidal abscess_, if the cortical region be affected, there may be paralysis or paresis of the opposite side, beginning with the face and then spreading to the arm and leg; or in the opposite order if the internal capsule be involved.

If the left temporo-sphenoidal lobe be the site of the lesion, aphasia may be met with, and if the abscess extends backwards, word-blindness may occur. If the centre of hearing be affected there may be complete deafness of the opposite side owing to its destruction; or tinnitus or hyperacusis if the centre be only irritated by the proximity of the abscess; or if the anterior extremity be involved anosmia or parosmia may be noticed. Another important sign, occurring in conjunction with the above symptoms, is a fixed pupil on the affected side.

_In a cerebellar abscess_ the symptoms are less marked, or may even be absent, so that the abscess may remain undiagnosed during life and only be discovered at the autopsy, which may perhaps have been performed on account of the sudden and unexpected death of the patient from rupture of the abscess itself. In walking, in addition to a peculiar staggering gait, there is a tendency for the patient to direct his course gradually towards the affected side. Lateral nystagmus, if present, is usually directed towards the affected side and has to be differentiated from that due to internal-ear disease. If a cerebellar abscess be associated with a labyrinthine suppuration and the latter is explored by operation, the nystagmus will still remain directed to the affected side. If, however, no cerebellar abscess be present the labyrinthine operation will be followed by nystagmus strongly directed to the opposite side. Optic neuritis and vomiting usually are more severe than in temporo-sphenoidal abscess. Headache, if present, may be referred to the occipital region, and there may also be slight retraction of the neck or pain behind the mastoid region as a result of localized and early meningitis of the posterior fossa. If the abscess be very large, there may be paresis or paralysis of the facial nerve and perhaps also of the upper extremity. The deep reflexes may also be altered, the knee-jerk being frequently absent on the affected side. The patient in the late stage usually lies curled up in bed on the side opposite to the lesion, with the knees flexed.

=Methods of operation.= Two methods may be employed:--

1. Trephining directly over the area of the abscess (rarely necessary).

2. First performing the mastoid operation and then following out the route of infection (usual method).

In the case of middle-ear suppuration, trephining has practically been abandoned, and rightly so, since it has become recognized that the intracranial abscess is due to direct extension of the pyogenic infection from the middle-ear and mastoid cavities.

The only circumstances in which trephining may be advised are--(1) If the diagnosis be certain and the operator has no experience of aural surgery. In a case of emergency he is wiser, perhaps, to trephine and drain the abscess, leaving the mastoid to be dealt with afterwards by someone competent to do so. (2) If, after performing the mastoid operation, the situation of the abscess be doubtful. In order to diminish the risk of infection of the brain by an exploratory puncture which may prove negative, the bone may be trephined a little beyond the mastoid wound, either above or behind, according as a temporo-sphenoidal or cerebellar abscess is suspected. If, however, it be considered advisable to make a fresh opening in the bone beyond the septic wound cavity, the aural surgeon will probably prefer to do so by means of the gouge and bone-forceps, to which he is more accustomed.

Trephining has also been advised if the patient is so ill that a prolonged operation is impossible; or if there is cessation of respiration during the operation itself, which may occur in a cerebellar abscess as a result of pressure on the medullary respiratory centres. To those accustomed to perform the mastoid operation, the opening of this cavity and the necessary removal of bone can be done more rapidly by the gouge or bone-forceps than by the trephine.

For whatever reason trephining is done, it is afterwards essential to perform the mastoid operation and to remove the primary focus of the disease, otherwise one of the fundamental principles of surgery will be neglected.

=Operation.= The preliminary preparation of the patient is the same as for the mastoid operation, only the head should be shaved over a wider area. The exposure of the field of operation is the same whether the brain is explored through a trephine opening or from an extension of the mastoid operation.

In the case of the temporo-sphenoidal lobe, it is necessary to extend the incision behind the auricle vertically upwards for an inch or more (Fig. 252); whereas if the cerebellum has to be explored, an incision is carried backwards at right angles to the post-aural incision, just below its mid-point (Fig. 253). In the former case, on reflecting the soft tissues from the underlying bone, the squamous portion of the temporal bone, immediately above the zygomatic ridge, will be exposed; in the latter, the base of the skull behind and below the mastoid process and lateral sinus will be laid bare.

1. =Trephining.= The trephine used should be three-quarters of an inch to one inch in diameter according as the patient is a child or an adult. Either the hand trephine or Macewen’s improved pattern mounted with a guard may be used. If available, the trephine may be worked by a motor, but in this case it should be remembered that the bone will be pierced more quickly than by the hand instrument.

_Trephining for a temporo-sphenoidal abscess._ The object of the operation is to expose the lowest portion of the middle fossa just above the roof of the antrum and tympanic cavity. The trephine, therefore, should be placed so that it is situated just above the suprameatal spine, its lowest margin being slightly above the zygomatic ridge (Fig. 251). After the disk of bone has been removed the exploration of the abscess is then carried out.

_Trephining for a cerebellar abscess._ The point at which the bone is trephined must be behind and below the curve formed by the transverse and sigmoid portion of the lateral sinus; that is, behind the mastoid process and below Reid’s base-line.

If the mastoid operation has not been performed, the centre pin of the trephine should be placed at a point 1-1/4 to 1-1/2 inches behind the centre of the external auditory meatus, and an inch below Reid’s base-line (Fig. 251). If, however, the mastoid has already been opened and the lateral sinus exposed, the trephine should be placed so that its anterior border is just behind the sinus and its upper border well below Reid’s base-line.

2. =After performing the mastoid operation.= If this has been done already, the wound is reopened, and cleansed by filling it with hydrogen peroxide. After gently curetting away any granulations the wound cavity is irrigated and then packed in order to dry it. Under good illumination, careful inspection is made to see if a fistula or a tract of diseased bone extends in any direction. Whether the middle or posterior fossa should first be explored depends not only on the clinical symptoms but also on the condition found on opening the mastoid cavity.

=Opening of a temporo-sphenoidal abscess.= A temporo-sphenoidal abscess may be explored either through its lowest point, that is, through the roof of the antrum and floor of the middle fossa, or through its outer wall just above the zygomatic ridge. To obtain a view of the roof of the antrum and mastoid cavities, the head of the patient should lie almost flat on the operating table and be turned well over to the opposite side. The bony roof of the antrum and mastoid is removed by means of the gouge and mallet, and so expose the dura mater covering the floor of the middle fossa (Fig. 252). If a fistula communicates with the antrum cavity and the middle fossa, the bone surrounding it is first attacked. In removing the bone, it must be remembered that the tegmen tympani is exceedingly thin, and unless care is taken pieces of bone may be pressed inwards on to the overlying dura mater. Sufficient bone should be removed to determine whether the dura mater is normal or not. To do this it may be necessary to chisel away the tegmen tympani outwards until the squamous portion of the temporal bone is reached, after which a pair of bone forceps may be used until a sufficient opening is obtained.

The condition found on examination of the dura mater varies. In many cases it is congested or covered with granulations at the site of the infection, and usually it is adherent to the underlying bone. At other times it seems normal.

Increase of the intracranial pressure, as shown by the bulging outwards of the dura mater, and absence of pulsation are suggestive of an abscess. These signs, however, are not conclusive, as on the one hand increased intracranial pressure may be due to other causes and on the other it is quite possible to have pulsation if the abscess be small and deeply placed.

If an extra-dural abscess be present, the intracranial cavity should not be explored at once unless this is absolutely necessary, but this step of the operation should be delayed for at least twenty-four hours. If, however, immediate operation be necessary, special precautions must be taken to render the part as aseptic as possible, and a fine layer of gauze should be packed between the margin of the bone and the dura mater in order to prevent further infection of the brain or meninges. In an uncomplicated case only sufficient bone should be removed to permit of the insertion of a large drainage tube; that is, the dura mater should not be exposed over a larger area than the size of a shilling.

If there be disease of the tegmen tympani and the symptoms point to a temporo-sphenoidal abscess, the brain should be explored through this opening in the bone (Fig. 252), as the abscess is thus not only drained through its most dependent part, but also through its stalk.

If, however, the diagnosis be doubtful, the temporo-sphenoidal lobe may be explored through a fresh opening, just above the tegmen tympani. This will diminish the risk of septic infection from the mastoid cavity. After the dura mater has been exposed sufficiently a small incision is made in it, taking care to avoid wounding any of the vessels. With a pair of forceps the cut edge of the dura mater is drawn outwards and the incision is prolonged in each direction with a pair of blunt-pointed scissors. Similarly, the dura mater is cut through at right angles to the primary incision, so that four small flaps are made and turned back so as to expose the outer surface of the brain.

As a rule the dura mater, arachnoid, and pia mater are fused together by inflammatory adhesions, so that from a practical point of view they need hardly be considered as separate structures. Similarly, at the site of infection, the point of the so-called stalk of the abscess, the cerebral membranes are adherent to the underlying brain, especially if there has been any localized meningitis. For this reason it is sometimes necessary to peel away the dura mater from the brain, in order to expose the latter.

As a rule, very little fluid escapes: if present in considerable quantity, and if it escapes from between the dura mater and brain, it is an unfavourable sign, as it generally signifies early meningitis.

If meningitis be present, purulent lymph or secretion may be seen on the surface of the brain, either localized or spreading from the site of the infection.

If the intracranial pressure be great, the brain will bulge through the opening in the dura mater. If the abscess be very large and situated superficially, the thin layer of brain substance forming its outer wall may rupture as soon as an opening has been made in the dura mater. Sometimes, indeed, the pus may be seen to ooze through an opening in the dura mater, which may be found to communicate with the abscess cavity.

The next step is to open the abscess. Formerly a trocar and canula were used. This method is no longer in favour for the following reasons:--If the wall of the abscess cavity be very thick, it may not be pierced; secondly, the trocar may pass through the abscess cavity and enter the brain substance beyond without draining it; and thirdly, even if the trocar enters the abscess cavity the pus may be so thick as to plug its lumen. For these reasons a fine pair of Lister’s sinus-forceps or a narrow-bladed bistoury is recommended. In the ordinary case Lister’s forceps can be used.

The direction in which the brain is explored depends upon the point at which this is done. Thus, if the procedure be carried out through the tegmen tympani, the brain is explored in an upward direction. The forceps are made to pierce the brain for about an inch; the blades are then slightly dilated and the forceps partly withdrawn. If a large abscess exists, the cavity is usually opened at once and pus flows out along the track of the forceps. If the abscess be small and deeply placed, its cavity may not be entered on the first thrust of the forceps. In this case they are closed and withdrawn. The brain is then explored by thrusting the forceps first upwards and forwards, then upwards and backwards, and finally upwards and inwards; in the latter case it is unwise to pierce the brain for more than an inch and a quarter for fear of entering the lateral ventricle.

If the brain be explored through the outer wall of the temporo-sphenoidal lobe, the first direction in which this is carried out is directly inwards. If this be not successful, the brain is further explored in a direction forwards, upwards, or backwards, the exploratory instrument at the same time pointing slightly inwards.

If exploration proves negative, it may also be necessary to explore the cerebellum. If, however, the surgeon be still convinced that a temporo-sphenoidal abscess exists, he may next pierce the brain with the bistoury, in case the forceps has failed to enter the abscess cavity, perhaps owing to its walls being very thick. If all efforts fail to find the abscess, the little finger may be inserted into the brain itself to see if the resistant wall of an abscess can be felt. This procedure, however, should be avoided if possible, as by doing so it causes destruction of a certain amount of brain tissue.

If an abscess be opened a varying quantity of pus escapes, usually evil smelling. In the more chronic cases it is thick and greenish; in the acute cases it may contain shreds of necrosed brain tissue or be intermixed with bubbles of gas. Sometimes there is also an escape of turbid cerebro-spinal fluid, which if excessive is suggestive either that the lateral ventricle has been opened inadvertently or that the abscess has already burst into it. In these cases the patient is usually comatose or in the state of muttering delirium at the time of the operation.

After the abscess has been opened, the forceps or bistoury should be retained in position until the pus has drained away. A large tube is then pushed into the abscess cavity along the line of the forceps or bistoury. It is only permissible to withdraw the instrument with which the abscess has been opened after the end of the tube is well within the cavity. The outer end of the tube should be flush with the surface of the wound. To prevent it slipping too far into the brain, it may be anchored to the edge of the skin wound by a silkworm-gut suture. If the abscess be drained through the tegmen tympani, it will be difficult to bring the tube out into the wound without kinking it. For this reason I prefer to incise the brain substance slightly outwards after the abscess cavity has been reached, so that a tube can be inserted obliquely upwards and inwards at a point corresponding to the angle between the tegmen tympani and the squamous portion of the temporal bone. If the exploratory puncture has been made above the tegmen tympani and an abscess discovered, the question arises whether another drainage tube should not also be inserted into the brain through an opening in the roof of the antrum so as to drain the abscess from below. This, however, I do not think necessary.

In addition to the rubber tube, many varieties of drainage tubes have been suggested, such as decalcified chicken bone, as originally used by Macewen, and glass or silver tubes; the object of the latter being to resist the pressure of the brain, which may compress a rubber tube. The rubber tube is the simplest form of drainage, and if sufficiently thick it should be employed. To make more certain of free drainage, some surgeons use two tubes placed side by side. I think, however, one large tube (half an inch in diameter) is better than two small ones.

Irrigation of the abscess cavity is still a matter of opinion. If the abscess be small and circumscribed, the best method is to open it with as little disturbance as possible to the surrounding parts, insert a large drainage tube, and to do nothing further.

If, however, the abscess be large and irregular in shape, so that the drainage is not free, and especially if it be very septic and contains necrosed brain tissue, irrigation is justifiable if gently carried out. The best method is to insert a fine tube along the lumen of the large one and allow some warm saline solution to flow slowly along it into the abscess cavity, the fluid returning along the larger tube. If two tubes have already been inserted into the abscess cavity, the fluid injected through one will escape by the other. Whatever method is employed, care must be taken that there is free exit for the fluid, as otherwise the abscess cavity may become over-distended, and in consequence rupture of a portion of its wall may take place, especially the inner, which perhaps only consists of a thin layer of brain tissue separating the abscess from the lateral ventricle. During the act of irrigation there is a risk of some of the fluid, now loaded with septic particles, escaping between the surface of the brain and the dura mater and thus setting up a secondary meningitis.

=Opening of a cerebellar abscess.= The cerebellum may be explored from two different points, either in front or behind the lateral sinus. The posterior route is adopted if the abscess is superficial in the outer portion of the lateral lobe, usually the result of lateral sinus thrombosis or disease of the posterior mastoid cells. The anterior route is indicated if it is thought that the abscess is deeply placed in the anterior inferior portion of the cerebellum, that is, in those cases in which it is apparently a complication of labyrinthine suppuration, or the result of disease of the inner wall of the antrum and mastoid cavities (Fig. 253).

(_a_) _Behind the lateral sinus._ After exposure of the lateral sinus the bone is removed either by means of the gouge and mallet or by bone-forceps, until a considerable area of the dura mater is exposed behind and below the curve of the sinus (Fig. 253). The dura mater is then incised as already described.

The cerebellum is explored by thrusting the instrument inward for about an inch. As a rule the abscess is found at once. If it be not discovered at the first attempt, the instrument should be directed forwards, upwards, and inwards towards the posterior surface of the petrous bone. Care, however, must be taken that it is not pushed in too far, otherwise it may pierce the anterior upper margin of the cerebellum, and if an abscess be present, the meninges may thus become infected. If the surgeon has exposed the dura mater by trephining, it is necessary to push the exploratory instrument at least two inches inwards and forwards in order to reach an abscess situated in the anterior inferior portion of the cerebellum. In such cases it is by no means difficult to miss a small abscess, and further, drainage is frequently incomplete when an abscess is discovered. For this reason, if the cerebellum be explored first behind the lateral sinus and no abscess is discovered, it should further be explored by the anterior route in front of the lateral sinus. If the cerebellar abscess be secondary to lateral sinus thrombosis, and if there be no doubt as to the diagnosis, the inner wall of the sinus should be made as aseptic as possible, and the dura mater forming it incised freely; the cerebellum being thus explored through the site of infection.

(_b_) _In front of the lateral sinus._ The lateral sinus is first exposed (Fig. 253). The triangular area of bone situated in front of it, between it and the semicircular canals, and forming the inner boundary of the antrum and mastoid cavities, is now removed with the gouge and mallet or with a suitable pair of forceps. If it be certain that internal-ear suppuration exists, or if the operation be secondary to opening of the labyrinth, the posterior wall of the petrous bone may be removed until the internal auditory meatus is almost reached. If, however, the labyrinth be intact, care must be taken not to chisel away too much bone for fear of encroaching on the posterior semicircular canal. On exposure of the dura mater an extra-dural abscess may be met with, usually the result of internal-ear suppuration. Even if no pus be seen, it is always a wise precaution, if internal-ear suppuration coexists, to separate the dura mater from the posterior wall of the petrous bone by means of an elevator in order to prevent any deeply situated extra-dural abscess being missed. After the dura mater has been exposed sufficiently it is opened by a crucial incision. In this region absence of increased tension within the brain and lack of bulging outwards of the cerebellar tissue do not necessarily imply the absence of an abscess; the cerebellum to all appearances may appear normal and flaccid, although a small abscess may be present.

The cerebellum is explored in various directions to a distance of not more than one inch. After the pus has been evacuated a tube is inserted as described above. In the majority of cases this method is far superior to opening the cerebellum behind the lateral sinus, especially as it is now recognized that the chief cause of cerebellar abscess is internal-ear suppuration.

=After-treatment.= This is similar to that of any ordinary abscess, but care must be taken that free drainage is maintained. The main part of the mastoid wound is lightly plugged with gauze, the tube inserted into the brain abscess being brought flush with the surface of the skin. The gauze filling the wound cavity should be arranged around the tube so that it rests comfortably within the wound and is not kinked. If the drainage tube be in its proper position, pus should be seen to ooze out of it.

Although the mastoid cavity itself need not be dressed daily, if necessary the outer dressings may be removed twice a day, in order to see that drainage of the abscess is continuous. After the first two or three days, the tube is gradually shortened. If the abscess be a recent one and not encapsuled, it becomes rapidly obliterated by pressure of the surrounding brain tissue, so that the tube may be forcibly ejected within a few days. On the other hand, if the abscess has existed for a considerable period and is bounded by a thick wall, which may be extremely resistant, the purulent discharge may continue for many days and necessitate the continuance of drainage. Generally speaking, the tube may be shortened every second or third day, and can usually be dispensed with by the end of the second week, if not before. It is, however, very necessary that the tube should not be withdrawn until it is certain that the abscess cavity has been obliterated completely.

The general treatment of the case in no way differs from that already described for the mastoid operation in which the wound has been left open posteriorly.

=Complications.= (i) On turning back the flaps of the dura mater, a hernia, consisting of friable congested brain tissue, may occur at once. This is extremely rare as a result of a simple abscess of the brain, but is significant of encephalitis frequently associated with meningitis (see p. 436). If an abscess be suspected, the brain should be explored as already described. If, however, no abscess be discovered, the treatment consists in removal of more bone and further incision of the dura mater, in order to permit of free drainage and to relieve tension.

(ii) Opening into the lateral ventricle. This may be due to rupture of its wall owing to the sudden diminution of pressure from too rapid drainage of the abscess cavity, or it may occur accidentally from thrusting in the exploratory instrument or drainage tube too deeply. Its occurrence is evidenced by the sudden gush of cerebro-spinal fluid. The ultimate danger is subsequent infection of the cavity, which, unfortunately, frequently occurs.

(iii) Cessation of breathing. This is more likely to occur in a cerebellar abscess in consequence of direct pressure on the medullary respiratory centres. The immediate treatment is to do artificial respiration and to open the cerebellar abscess by the quickest method possible. If this be successful, respiration probably will be restored.

=Prognosis and subsequent progress.= In an uncomplicated case a favourable prognosis may be expected, provided the abscess is successfully opened and drained without much disturbance of the surrounding parts. Many factors, however, may lead to a fatal result. With regard to recovery: in 100 cases taken from the records of the London Hospital during the last ten years, recovery took place in 20% operated on for cerebral and 10% for cerebellar abscess. Other statistics give a much higher percentage of recovery, but it must be remembered that in hospital patients a large number of the cases are only seen by the surgeon at a very late stage, when the brain abscess is complicated by other intracranial or suppurative lesions, and the patient is in an almost moribund condition; so that the operation may only be undertaken as a forlorn hope.

If the operation is going to be successful, the head symptoms quickly disappear. Even if the patient was comatose before operation, the recovery may be so rapid that his mental condition may be almost normal within twenty-four hours. In many cases, if the abscess be a large one, convalescence will be tedious or prolonged; sometimes, indeed, complete restoration of the mental faculties, in spite of a most successful operation, will not be obtained. The chief relief to the patient is the cessation of the terrible headaches from which he has been suffering.

Unfavourable symptoms are the sudden onset of pyrexia accompanied by delirium usually the result of diffuse meningitis, or of infection of the lateral ventricles. In the latter case there is a rapid termination in drowsiness, coma, and death.

Although the brain abscess may be draining freely, the patient for some days may lie in a semi-comatose condition as a result of œdema or inflammation of the surrounding brain tissue; in such cases prognosis is difficult, but hope of recovery may be entertained if the pulse and temperature keep practically normal.

=Recurrence of symptoms.= This may take place within the first few days after the operation as a result of infective cerebritis, the presence of another abscess, or faulty drainage; or at a much later period, owing to the formation of another abscess or to a cyst within the brain at the site of the former abscess.

1. If the recurrence of the symptoms appears immediately after the operation, the wound should be inspected carefully, if necessary under an anæsthetic. If drainage be not free, the tube should be removed and a pair of forceps inserted along the track leading into the abscess, their blades being then slightly opened and withdrawn. On doing this an accumulation of pus may escape. The cavity may then be irrigated gently with saline solution and a larger tube inserted.

If, however, this procedure does not give a satisfactory result, the finger may be inserted into the brain to feel if the abscess is loculated. By this means any existing septa may be broken through; or if a feeling of resistance suggests the presence of another abscess, this part of the brain can also be explored. It must also be remembered that although a temporo-sphenoidal abscess has been opened successfully and is draining well, the continuance of the symptoms may be due to a coexisting abscess of the cerebellum, or _vice versa_; in other cases, in spite of all care, the patient gradually sinks, partly from exhaustion and partly from general toxæmia, the result of infective cerebritis.

2. Recurrence of symptoms at a later period. The occurrence of a fresh abscess is usually owing to the fact that the primary focus of the disease has not been completely removed at the first operation; for instance, if the surgeon only trephined and drained the abscess without performing the mastoid operation.

A cyst is usually the result of the abscess having been encapsulated and its wall not having been removed at the first operation. If a cyst be discovered on exploring the brain in consequence of these symptoms, its wall should be removed if possible.

Apart from symptoms of intracranial pressure, the patient may suffer from attacks of Jacksonian epilepsy from time to time, presumably due to the post-operative adhesions. If they continue in spite of conservative treatment, it may become necessary to operate in order to remove this source of irritation (see Vol. III).

SECTION IV

OPERATIONS UPON THE LARYNX AND TRACHEA

BY

W. DOUGLAS HARMER, M.C. (Cantab.), F.R.C.S. (Eng.)

Surgeon to the Throat and Nose Department, St. Bartholomew’s Hospital