Part 69 (1/2)

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 relations.h.i.+p 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.