Volume 1

Green's Encyclopedia and dictionary of medicine and surgery / edited by J. W. Ballantyne.

Date:
1906-1909
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Green's Encyclopedia and dictionary of medicine and surgery / edited by J. W. Ballantyne. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

    555/576 (page 523)
    Hernia Cerebki When a protrusiini of 1 train takes place through an acquired opening in tlie skull it is termed a hernia cerebri. (Protrusion of the brain or its nicnibranes through a congenital defect in the skull is met with in meningocele, encephalocele, etc.) In every case hernia cerebri is caused by increased intracranial pressure forcing the brain through the abnormal opening in the skull and dura; for even when such an opening exists, if there be no increased intracranial pressure, herniation will not take place. The brain will not protrude miless the dura mater is woimded as well as the skull. The condition i.s usually found either in connection with compound fractm-es of the skull, syphilitic necrosis, or after surgical oj^erations. The necessary factor of abnormally great intracranial pressure is produced by one of the following :— {a) Intracranial hsemoi'rhage. {b) G^]dema of the brain. (c) Tumour of the brain. {d) Inflammatory swelling of cranial contents. Of these the last is by far the commonest. It is very apt to ensue as the result of septic wounds of the br;iin, accidental or surgical, and is a not unconunon se(juela of compound fractvu-es of the skull in which asepsis has not been obtained. In some cases a definite localised aV)scess is found in the brain sulistance beneath the hernial tiimo\ir. Again, in operating on a tumour of the brain the surgeon may either be unable to remove the growth, and a hernia cerebri may follow the operation (a result which is highly beneficial and desirable in most instances, as thereby relief is afforded to the intense intracranial pressure), or as a result of his interference with the brain a spreading oedema may be set up, which increases the intraei'anial pressure in such a way as to ca^ise a hernia cerelni. In a few cases of depressed fracture of the skull it happens that an effusion of blood (assisted, perhaps, by depressed bone) may produce sufficient pressure to cause hernia; and this form of the disease may appear immediately after the injury. Usually some days, or even weeks, elapse between the injury to the skull and the formation of the hernia. The portion of brain protruded generally escapes through a small opening in the sk\ill ; for if there were a large opening in the skull, the intracranial pressure w'ould probably have been sufficiently relieved to prevent the formation of a hernia. The herniated l)rain tissue—at first red, tiu-gid, and pulsating—becomes oodematous and swollen, and eventually disorganised, or even sloughing on its surface, these changes lieing due to the pressure on the vessels in the neck of the tumour l»y the margins of the opening through which it has escaped. The /)»w/?Jos«s of hernia cerel)ri is unfa^•(Jur- able: only about one-fourth of all cases recover; most of these recoveries are in cases of hfemor- rhagic or l)ony pressure which has been relieved by operation. Treatment.—The most important indication is to pre^'cnt the formation of hernia by taking any steps that may be possible to relieve intra- cranial pressure, and to be scrupulously carefid about such matters as asepsis and drainage. When a hernia has once formed no very active treatment of the tumour is of any use ; indeed, it is usually mischievous. It is evident that as 1 jng as the intracranial pressure remains our chief ol)ject should be to deal with it rather than with the hernia. It has been suggested to apply pressure to the mass by means of elastic bandages, or to treat it with astringents, alcohol, etc., or even to shave it oft. All these plans are of very doubtful value. If the intra- cranial pressure he lessened by the absorption, let us say, of some tuberculous deposit at the base of the brain, the hernia will recede of its own accord and the wound will close. If, on the contrary, the intracranial pressure increases, the most sensible line of treatment is to con- siderably enlarge the ojiening in the skull through which the hernia has come, in order to relieve general pressure on the brain, and 230ssibly to minimise injury to the protruded cortex. Ce1'IIAI,0CET>E It occasionally happens that the membranous layer which goes to form the skull of the newly- born infant is imperfectly developed; that ossification in the cranial bones is consequently incomplete ; this gives rise to a protrusion of the membranes and other cranial contents at those portions of the skull which ofter least resistance. In some cases the presence of intrauterine hydrocephalus seems to l)e partly or wholly responsible for the condition. These protrusions usually take place in the middle line of the head, the commonest position being posteriorly, in connection with the occipital bone, the tumour projecting through an opening M'hich runs from the foramen magnum up to the occipital protuberance, called by Sutton the temporary occipital fontanelle. Next in frequency they are foinid at the root of the nose in relation to the fronto-nasal suture; but they are also met with occasionally else- wdiere in connection with the sutures of the skull, sometimes at its lateral aspects, and may project into tlie orl)it, mouth, or nose, in which latter position they have been mistaken for polypi. There are three varieties of the condition depending on the contents of the protrusion. 1. Meningocele, in which there is a protrusion