TUMOURS). For our immediate purpose the important fact is that the majority are gliomas, arising from the supporting stroma of the cerebral tissue and possessing no capsule. This means that they cannot be enucleated without leaving tumour cells behind. Nor can a block-resection of sound tissue with the tumour en closed be performed without inflicting severe and permanent dis ability on the sufferer, though this has been advocated (Dandy). Fortunately many gliomas grow very slowly so that if the main mass is removed relief for some time at least follows. Further, they show a tendency to degenerate into relatively benign cysts which may be tapped, and lastly, some types are sensitive to irradiation by X-rays or radium. The endothelioma, on the other hand, is benign and once removed does not recur, but unfor tunately many lie in inaccessible positions and are extremely diffi cult problems technically. Pituitary tumours are also benign, but can rarely, if ever, be totally extirpated, whilst tumours arising from the auditory nerve are in similar case; fragmentary removals give most satisfactory results, and the patient often lives for years after the operation.
All intracranial tumours for one reason or another tend to interfere with vision, and indeed if left untreated, blindness is the almost uniform end. Operation to relieve pressure and save sight must be undertaken early. Generally the intervention will take the form of a decompression, a sufficiently wide opening being made in the skull and dura mater to allow the brain to bulge—a safety valve as it were. Since the bulging brain needs protection the opening is best made beneath the temporal muscle (Cushing), and since haemorrhages may occur in the released area with con sequent impairment of function the opening should be over a relatively "silent" area, such as the right temporal lobe. Up to recent years little more than this decompression was attempted but there is a growing tendency now to attack in addition the tumour itself. Even if it should be irremovable the resection of bone over it will allow more competent attack by post-operative radiation. It may be said that the results of surgery so far as concerns permanent cure leave much room for improvement, but the treatment of brain tumours is still relatively in its infancy. So far as concerns immediate relief from agonising headache, from failing vision and the like, the results are usually good.
In very bad cases the patient may be comatose and operation is not always then desirable, the brain tissue will veritably burst when the skull is opened so high is the tension. Such patients may be recalled to consciousness and better fitted for operation by the intravenous administration of hypertonic solutions. We owe this advance to Weed and McKib ben who advocated the use of 15% salt solution intravenously. Fifty to one hundred c.cs. "pulls over" the excess fluid from the cerebro-spinal network and sometimes lowers tension remarkably. Glucose in 5o% strength acts more slowly but for a longer time. This type of physiological medication is proving helpful in the surgery of tumours, for the fact that they cause such huge rises in brain pressure has militated against successful attack upon them. Were pressure normal, exploration and extirpation would be very much easier; hypertonic therapy marks a step in the desired direction.
A complete neurological examination calls for considerable co-operation on the part of the patient, and in those cases where a patient is too drowsy and ill to pay much heed to questions or respond to requests it is sometimes difficult to say just where a brain tumour may be. In such cases use may be made of ventriculography or cerebral pneumography. A small hole having been made, the lateral ventricle is punctured and cere bro-spinal fluid drawn off, a quantity of air equal to the amount of fluid extracted is injected and an X-ray will now show the ven tricles clearly outlined. Deductions as to the position of the tumour may be drawn from the shape of the ventricle. The method is not without danger and the interpretation of the X-rays is of ten puzzling.
Abscess of the brain usually forms by direct extension from a focus of disease in the skull, usually in an acces sory air-sinus such as the mastoid antrum or frontal sinus. The 'mortality is high because the infection tends to spread into the surrounding brain tissue as a septic encephalitis. The chief sites are the cerebellum and temporosphenoidal lobes. Sometimes abscesses arise in the brain by lodgement of septic particles from the lungs when purulent bronchitis (bronchiectasis) is present. Drainage of the abscess is the only logical and successful treat ment, the result depending often on the nature of the infection rather than on perfection of technical skill.
Jacksonian epilepsy, localized muscle group con vulsions due to a circumscribed lesion of the motor cortex, has received much attention from surgeons. In those cases where there is indeed a focus of irritation, operation usually does good, but many apparent Jacksonian attacks are manifestations of ordi nary epilepsy which has so far no discovered pathological basis.
There is no medical cure for trigeminal neuralgia; the only hope lies in some form of operation designed to block the passage of impulses along the nerve. This may be attained by alcohol injections, but after about a year this needs repeating for the nerve fibres regenerate. The only permanent cure is division of the sensory root of the great ganglion of the nerve (Gasserian ganglion), a much less severe operation than the removal of the ganglion which was the custom a few years ago. It is often possible to save the fibres supplying the eye. It is usual to give alcohol injections first to accustom the patient to the idea of numbness, for in neuralgia cases the more complete and lasting the anaesthesia obtained the more complete the cure. The deadening of the skin has no ill effects, but when the eye is totally anaesthetic it is very apt to become inflamed (neuro paralytic keratitis) and requires careful attention. Protective glasses must be worn out-of-doors. Sufferers from severe neuralgia are usually well prepared for any sacrifice to be rid of the pain. No deformity follows the operations. (G. J.)
