Of the intracranial complications, meningitis is most frequent, and next in order cerebellar abscess. In addition, thrombosis of the bulb of the jugular vein may take place from infection through one of the smaller tributary veins; or a localized extra-dural abscess may be found situated along the posterior portion of the petrous bone in consequence of direct extension of the infection through the internal auditory meatus, or as a result of empyema of the endolymphatic sac. This latter condition is almost impossible to diagnose, but may be discovered accidentally if the vestibule is opened by the posterior route according to Neumann's method.

=Difficulties.= The chief difficulties are anatomical, and the inability to obtain a clear view owing to general oozing of blood.

The first is generally due to insufficient removal of bone; the second can usually be controlled by means of good a.s.sistants and the frequent employment of hydrogen peroxide or of adrenalin solution.

=Dangers.= _Injury to the facial nerve._ This, as might be expected, is not infrequent. If a burr be used, the nerve may be completely torn across and permanent paralysis may result. If, however, the gouge and mallet be employed, complete recovery usually takes place, as the injury seldom consists in complete destruction of the nerve.

_Opening up of the internal meatus._ This may be accompanied by a gush of cerebro-spinal fluid. There is nothing to be done except to try and keep the part as clean as possible and see that there is free drainage.

Undoubtedly, as a result of this mishap, death has afterwards occurred in consequence of septic meningitis.

_Injury to the internal carotid or bulb of the jugular vein._ These are possibilities which, however, should not occur if ordinary care is taken.

=Prognosis.= The prognosis of labyrinthine suppuration is always grave, owing to the frequency of intracranial complications.

The most favourable cases are those in which the disease is localized and is of chronic duration. The most unfavourable are those in which acute suppurative labyrinthitis is accompanied by extensive bone disease.

According to statistics, the mortality is about 50% in cases not operated upon. As a result of operation, this has been reduced to less than 20%, and in the majority of these cases the ultimate fatal result cannot be put down to the operation itself. The patient is frequently seen too late, that is, after intracranial complications have already occurred. There is no doubt that the death-rate will diminish proportionately according as the necessity of operating early becomes more and more recognized.

With regard to hearing, extensive operations upon the labyrinth lead to complete deafness; nor, indeed, can recovery of hearing be expected except in those cases in which the disease and operations have been limited to the semicircular ca.n.a.ls and to the posterior portion of the vestibule, and even then recovery of hearing is exceptional.

CHAPTER VIII

OPERATIONS FOR EXTRA-DURAL ABSCESS AND MENINGITIS OF Ot.i.tIC ORIGIN

ON INTRACRANIAL COMPLICATIONS IN GENERAL

As the intracranial complications of ot.i.tic origin are due to direct extension of the pyogenic infection through the temporal bone to the cranial cavity, it follows that they will depend on the extent of the disease within the temporal bone, the direction in which it has spread, and the virulence of the infection. For this reason, also, the site of the intracranial lesion is always in close relationship with the area of the diseased bone. Thus, if the infection spreads upwards through the attic and tegmen tympani, it may lead to extra-dural abscess or to meningitis of the middle fossa, or to a temporo-sphenoidal abscess.

Similarly, disease of the mastoid cells posteriorly may give rise to a perisinuous abscess, to meningitis of the outer surface of the posterior fossa, to lateral sinus thrombosis, or to a cerebellar abscess situated superficially and involving the outer portion of its lateral lobe just behind the lateral sinus; or caries of the floor of the tympanic cavity may give rise to thrombosis of the jugular bulb; or internal-ear suppuration to an extra-dural abscess occupying the posterior surface of the petrous bone, to meningitis of the posterior fossa, or to an abscess of the cerebellum deeply placed in its anterior inferior angle.

Operation is always imperative unless the patient is seen too late and it is obvious that the condition is hopeless.

Before operation is decided on the following points must be carefully considered: (1) Is it possible that the symptoms simulating the intracranial lesion are due to suppuration still limited to the temporal bone? (2) What is the character of the lesion? and (3) What is its situation?

As a rule, so long as the suppurative process is limited to the middle ear and to the mastoid region, the symptoms are those of a local septic infection. At the same time it must be remembered that in infants and in young children it is not uncommon for retention of pus within the middle ear to produce a clinical picture closely simulating an intracranial suppurative lesion. The ear, therefore, should always be inspected in every case. Sometimes a bulging membrane is discovered or the existing perforation is found to be insufficient for drainage. In such cases the symptoms may subside on free drainage being obtained by the simple act of paracentesis of the tympanic membrane.

If, however, free drainage already exists, the mastoid operation should be performed at once.

If the intracranial symptoms be still somewhat indefinite, and there is no apparent urgency, the intracranial cavity should not be explored immediately unless this is found to be imperative at the time of operation. This can be done later, if the symptoms do not subside.

Although exploration of the intracranial cavity is always urgent when it is certain that an intracranial suppurative lesion is present, yet to explore with a negative result is a grave misfortune, owing to the possibility of infecting the intracranial cavity.

Although the surgeon may be certain that an intracranial lesion is present, yet it may be very difficult to determine its character or whether several lesions coexist. The surgeon must therefore be prepared to act according to what he finds at the time of operation.

Thus, if exploration of the temporo-sphenoidal lobe be negative, and yet the cardinal symptoms point to an intracranial abscess, the cerebellum must also be explored. Again, if the diagnosis of intracranial abscess be doubtful before operation, and if, during the operation, lateral sinus thrombosis be discovered, it is wiser to limit the operation to tying of the jugular vein and removal of the septic thrombus. The bone, however, should be removed above and behind the sinus so as to expose the dura mater covering the temporo-sphenoidal lobe and the cerebellum.

In such cases, if the symptoms of intracranial suppuration still continue, it is an easy matter to explore the temporo-sphenoidal lobe or cerebellum at a subsequent operation.

Although under exceptional circ.u.mstances (see p. 461) it may be justifiable to open an intracranial abscess by directly trephining the skull over it, yet free opening of the mastoid process should be the first step in the operation, as the primary focus of the disease exists within the temporal bone. In addition, much information may thus be gained in a doubtful case with regard to the situation of the intracranial lesion.

OPERATIONS FOR EXTRA-DURAL ABSCESS

This is far more common as a sequel of acute than of chronic disease of the mastoid process.

=Indications.= Operative interference is indicated in order to permit of drainage. An extra-dural abscess is frequently discovered accidentally, especially if the surgeon follows out the golden rule to trace any patch of carious bone to its limit. In doing so he may suddenly meet with a gush of purulent discharge coming through an opening in the bone in the region of the tegmen tympani or sigmoid sulcus.

Although an extra-dural abscess may give rise to no special symptoms, the following are suggestive:--

1. If, in spite of opening up the mastoid cells and antrum, pyrexia and headache persist, especially if the headache be localized to the affected side and accompanied by tenderness on pressure above the ear or behind the mastoid process.

2. If, before operation, there be a very profuse discharge from the ear, apparently too copious to come from the tympanic cavity or mastoid antrum.

3. In children an extra-dural abscess may give rise to symptoms of cerebral irritation or compression if it extends upwards from the tegmen tympani along the parietal region; or, if situated in the posterior fossa, to retraction and stiffness of the neck.

Although such symptoms may be also a.s.sociated with an intracranial abscess or meningitis, yet, if on exploration of the intracranial cavity a large extra-dural abscess be discovered, further operation may be postponed (unless its extension is obviously necessary) until time is given to see whether the symptoms will subside or not.

=Operation.= If the mastoid process has not been opened already, the simple or the complete operation is performed, according to whether the suppuration is recent and acute, or is of long standing.

If, however, this has been done, the wound is reopened, all granulations are curetted away, and the cavity is cleansed and dried.

The antrum and mastoid cavity are then thoroughly examined. If a fistula in the bone already communicates with the abscess, pus may be seen to ooze through it. If not, careful search is made for any carious tract of bone, which is now followed up until the dura mater is reached.

After the pus has drained away more bone is removed so as to expose the dura mater fully over the infected area, which is usually vascular or covered with granulations. The latter, however, should be left severely alone. If the abscess be situated in the middle fossa above the tegmen tympani, the bone is best removed by chiselling upwards until the lower margin of the squamous portion of the temporal bone is reached. Then, with a pair of bone forceps, more bone can be punched away quickly until a sufficient opening is obtained (Fig. 243).

Exploring with the probe and curetting away of granulations should be avoided as far as possible for fear of injuring the sinus. If its wall be already inflamed, it may be torn through, and the resulting haemorrhage may render the further steps of the operation a matter of extreme difficulty.

Before completion of the operation, a blunt-pointed seeker should be pa.s.sed round the edge of the opening in the bone to see that its margin is smooth and even, and all sharp edges of bone bordering on the dura mater should be removed. If this precaution be neglected, a splinter may get pressed inwards and injure the dura mater, and thus set up meningitis.

If possible the bone should be removed until the healthy dura mater is reached. If the extent of the abscess prohibits this, its limits, however, should be ascertained. This can be done by pressing the dura mater inwards with a spatula so as to separate it from the overlying bone.

The final step is to irrigate the cavity with warm boric or saline solution and to insert drains of gauze or of fine india-rubber tubing between the dura mater and bone. The wound cavity is then lightly packed with gauze and a simple dry dressing applied.

=After-treatment.= Provided there be no other intracranial symptoms, recovery should be as rapid as in the case of simple inflammation of the mastoid process. In the after-dressings, however, special care should be taken not to press in the gauze roughly or tightly against the still inflamed dura mater, in case of injuring its surface and causing further extension of the pyogenic infection to the meninges or lateral sinus.

The dressings should be changed daily. It is sufficient to irrigate the wound with some mild aseptic lotion and afterwards to repack it lightly.

If Schwartze's operation has been performed, the after-treatment is similar to that already described (see p. 387). In the case of the complete operation, after the purulent discharge has practically ceased and the surface of the wound appears healthy, the packing of the cavity may be carried out through the meatus, instead of through the posterior wound, the latter being then allowed to close.

=Intracranial complications.= Infection of the lateral sinus is the most frequent complication, but meningitis, ulceration of the surface of the brain, or intracranial abscess may also occur.

One or more of these complications may already exist at the time of operation, but may not be sufficiently marked to warrant further exploration of the intracranial cavity. It is wiser, therefore, to give a guarded prognosis during the first few days after the operation, not only with regard to recovery, but also to the possibility of further operative procedures becoming necessary.

OPERATIONS FOR MENINGITIS OF Ot.i.tIC ORIGIN

Formerly the onset of symptoms of meningitis was a distinct contra-indication to operation. More recently, however, this view has become modified, especially as it has been shown definitely by Macewen, Jansen, Brieger, and others that recovery is possible if operation is undertaken sufficiently early before the inflammation of the cerebral membrane has become diffuse.