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
CHAPTER I
ENDOLARYNGEAL OPERATIONS
Indications. (i) Tumours. Tumours of the larynx are more often innocent than malignant. Sir F. Semon[5] collected 12,297 cases seen between 1862 and 1888 by 107 laryngologists, and of these 10,747 (or 88%) were benign and 1,550 (or 12%) were malignant. Of the innocent forms, papilloma, either simple or multiple, occurred in 39%; fibroma, sessile or pedunculated, was next in frequency; cystic tumours were not nearly so common; and other forms, including myxoma, angeioma, adenoma, lipoma, and enchondroma, were rare. The period during which these tumours are most common is between the ages of 20 and 40 years, but they are also frequent during childhood.
Malignant growths occur at a later age, mostly between the ages of 40 and 60, and attack males more than females. Carcinoma is far more common than sarcoma, and is generally of the squamous-celled variety. Endothelioma has not often been discovered.
The importance of distinguishing innocent from malignant tumours is greater now than in former years, since it is agreed that endolaryngeal operations are preferable for the eradication of the former, while the latter are better treated by extra-laryngeal methods. Moreover, the differential diagnosis has steadily improved, owing to the more general use of the laryngoscope and the introduction of recent methods of examination. Thus, by direct laryngoscopy it is possible to investigate children as easily as adults. Microscopical examination of fragments removed with laryngeal forceps is of great value in confirming the clinical diagnosis; the sections can be made by freezing, or in paraffin, the latter method requiring, with recent improvements, not more than twenty-four hours. Semon, who has done more than any other man to improve the early diagnosis of malignant disease of the larynx, is strongly in favour of such examinations. It must be remembered, however, that the result is sometimes inconclusive, for it is difficult to be certain that the actual growth has been removed. In cases that are thought to be malignant, it is better to open the thyreoid[6] cartilage than to rely upon endolaryngeal operation, as there is a danger of stimulating the growth to greater activity, especially by repeated interference. When the thyreoid cartilage has been opened, the whole disease can be explored thoroughly and a fragment selected from which to make a frozen section. In the majority of cases a definite diagnosis can thus be arrived at, and even when it is necessary to examine several fragments the amount of time lost is small.