Part 73 (1/2)

Extreme vascularity of the bone is not unusual after ligature of the jugular vein. In these cases the surgeon must rely on the cleverness of the a.s.sistants in keeping the field of operation clear by careful swabbing.

In exposure of the jugular vein there may be difficulty in finding the vessel, especially if the cervical glands are enlarged, or if there be matting together of the tissues in consequence of periphlebitis or cellulitis. In these cases the best plan is to identify the common facial vein and then trace it down to its entrance into the jugular vein.

With regard to the sinus, the chief danger is injury of its inner wall whilst curetting out its contents: this may afterwards give rise to meningitis or a cerebellar abscess. Accidental p.r.i.c.king of a non-thrombosed jugular vein may allow of entry of air into the vein and so cause death: this is a catastrophe I have not yet met with. Also, if the operator be careless or inexperienced, he may injure the carotid artery or vagus nerve; in the former case the only thing to do is to ligature the artery above and below the wound.

=Complications.= The chief intracranial complications are meningitis and cerebellar abscess; the former usually from extension of the septic thrombosis along the petrosal sinuses. If, at the time of operation, it be doubtful whether intracranial suppuration already exists or not, the surgeon should content himself with removing the septic thrombus from the sinus and await further symptoms. At the time of the operation, however, sufficient bone should be removed to expose the dura mater over the cerebellum. If, in addition to the clinical symptoms, the appearance of the dura mater, the increased intracranial tension, and the absence of palpation suggest the presence of an abscess, the cerebellum should then be exposed and explored (see p. 467). Before doing this, the wound should be made as aseptic as possible and a fresh set of sterilized instruments used.

The complications resulting from general septic infection are pyaemia and septicaemia.

=Prognosis.= The prognosis depends entirely on whether the septic focus can be completely removed or not. Failure to do this is frequently due to the operation not having been sufficiently extensive. It is a matter of experience that if a second operation has to be performed recovery seldom takes place. For this reason the first operation must be thorough.

If such cases could be operated on in the earliest stage whilst the infective thrombus was still limited, without doubt a higher percentage of recoveries would be obtained. Unfortunately, the surgeon may not be summoned until too late, owing to the seriousness of the condition not having been realized.

In any individual case it is impossible to tell for the first few days after the operation what the ultimate result will be. Without operation a fatal termination is practically certain. As a result of operation about one-third of the cases may be expected to recover.

CHAPTER X

OPERATIONS FOR INTRACRANIAL ABSCESS OF Ot.i.tIC 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 relations.h.i.+p 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 pa.s.s 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 Korner's (_Die ot.i.tischen Erkrankungen des Hirns, der Hirnhaute 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 pyaemia.

=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 a.s.sociated 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.