Craniotomy

“ One man can do craniotomy, but it requires three to perform the caesarean section. If the woman's narrow pelvis has a conjugata vera of five or more centimetres, craniotomy, if properly done, is not dangerous to the mother. With a conjugata vera less than 5 centimetres it is more fatal than the caesarean section. If the women are septic, the mortality in {59} craniotomy is from 10 to 15 per centum ”

“ Treatment. The age of the patient must not be allowed to [55] weigh in the balance against operative treatment, for, if due precautions be taken, the new-born child stands operation well. Cushing points out that ‘the possibilities of surgical relief are limited to the first week or two after the hæmorrhage has occurred, for old cortical scars can neither be helped by medicine nor by the scalpel’.
The clot can be exposed by craniectomy or by craniotomy. The latter operation results in a more complete exposure, but the shock is undoubtedly more severe. ”

“ In the shafts of the long bones, owing to the excessive absorption of bone, the cortex becomes porous, the spongy bone is rarefied, and the bones readily bend or break under mechanical influences. When the disease is arrested, a process of repair sets in which often results in the bones becoming denser and heavier than normal. In the flat bones of the skull, the absorption may result in the entire disappearance of areas of bone, leaving a membrane which dimples like thin cardboard under the pressure of the finger—a condition known as craniotabes. ”

“ But the roofs of the orbits rise more obliquely into the cranial cavity, thus diminishing the space for the lower part of the anterior lobes of the brain, and the absolute capacity of the cranium is far less than that of Man. So far as I am aware, no human cranium belonging to an adult man has yet been observed with a less cubical capacity than 62 cubic inches, the smallest cranium observed in any race of men by Morton, measuring 63 cubic inches; while, on the other hand, the most capacious Gorilla skull yet measured has a content of not more than 341/2 cubic inches. ”

“ If death was not too soon the consequence of the puncture of the head of hydrocephalic patients, I am persuaded that we should see the bones gradually contract, and restore the cavity of the cranium to its natural dimensions. When we remove the dead piece from a long bone in necrosis, the new bone, formed on the exterior by means of the periosteum contracts in an evident manner. In paralysis of the optic nerve, its foramen becomes narrower. The orbit contracts when a cancerous eye has been extirpated. ”

“ In addition to the hideous deformity, the patient suffers from blocking of the nose, loss of smell, and protrusion of the eyes, sometimes followed by loss of sight. The condition is liable to spread to the zygomatic and frontal bones, the vault of the skull, and to the mandible. The base of the skull is not affected. The disease is of slow progress and may become arrested; life may be prolonged for many years, or may be terminated by brain complications or by intercurrent affections. ”

“ After removal of the disk, the dura mater should be peeled away from the under surface of the bone, and the whole of the depressed area cut away with the craniectomy forceps.
When there is osseous deficiency and when the gap is filled in with fibrous tissue, adherent to the margins of the gap and probably to the dura or brain as well, it is essential that this fibrous tissue should be freely removed. All evidence goes to substantiate the statement that meningeal irritation is the main cause of the fits, &c. ”

“ The cranium is of unusual size, and of a long-elliptical form. A most remarkable peculiarity is at once obvious in the extraordinary development of the frontal sinuses, owing to which the superciliary ridges, which coalesce completely in the middle, are rendered so prominent, that the frontal bone exhibits a considerable hollow or depression above, or rather behind them, whilst a deep depression is also formed in the situation of the root of the nose. The forehead is narrow and low, though the middle and hinder portions of the cranial arch are well developed. ”

“ One of these tracks was cut on each side, the surgeon explained, because it would give equal expansion to the two sides of the brain, and because it would cause death to cut through the middle of the top of the head, where lies "the superior longitudinal sinus." He left, therefore, the solid track of bone through the middle, and cut two grooves or tracks through the bone, one on either side, where nature (when she does not make a mistake) leaves soft or yielding edges, by means of which the normal skull expands to fit the needs of the brain within. ”

“ If the fracture of the cranium is accompanied by a large scalp wound, any fragments of bone or other foreign body are to be extracted at once, unless haemorrhage or the weakness of the patient are feared, and then a piece of linen is to be cautiously worked in with a feather between the cranium and the dura mater. In the fracture itself a piece of linen, or better of silk, is inserted, the apparent purpose of this double dressing being to protect the dura mater from the discharges and to solicit their flow to the exterior. ”

“ Cranioscopy, the study of the brain and its proportional development through the cranium, which is the method by which Gall made his discoveries, is a lost art in the medical profession, and I doubt if there is a single professor in any American or European medical college to-day, who has a competent knowledge of it. The art of cranioscopy requires as its basis a correct knowledge of the anatomy of the brain and skull, a correct knowledge of the localities of all the cerebral organs, and a practical skill in determining their development with accuracy. ”

“ Nor should we be justified in regarding the cranial conformation as perhaps representing the most savage primitive type of the human race, since crania exist among living savages, which, though not exhibiting such a remarkable conformation of the forehead, which gives the skull somewhat the aspect of that of the large apes, still in other respects, as for instance in the greater depth of the temporal fossæ, the crest-like, prominent temporal ridges, and a generally less capacious cranial cavity, exhibit an equally low stage of development. ”

“ The cranium is large in proportion to the size of the body. The skull is in the form of a wide oval and is wider than it is long. The elements of the skull were ornamented with a coarse sculpturing which partakes of the nature of incomplete radiations on the squamosal region. The different elements of the cranium can not be distinguished, although I think the outlines of the parietal are indicated. The position of the nostrils is well forward and they are slightly elongate transversely. The pineal foramen can not be determined. ”

“ If the inflamed brain tissue protrudes to an excessive degree during the operation itself, the opening in the skull should be enlarged, if it be not already of considerable magnitude, and the dura mater incised to the full limits of the opening. The protruding mass may then be cleanly excised by means of a scalpel. If, however, the brain tissue continues to prolapse, the wound cavity should be simply cleansed and protected by a dressing of sterilized gauze. If the encephalitis subsides, the hernia will not increase in size, and if the wound cavity be kept aseptic, it may gradually shrink. ”

“ The skull is nearly oval in form, convex externally, the bone being much thicker at the base than elsewhere, and it is, in every respect admirably adapted to resist any injury to which it may be exposed, thus affording ample protection to the brain substance which it envelops. The internal surface of the cranium presents eminences and depressions for lodging the convolutions of the brain, and numerous furrows for the ramifications of the blood-vessels. ”

“ The external configuration of the skull is therefore not a true criterion of character when the influences of education, society, food, drink and disease have greatly changed the natural bias, although reliable in a strictly normal condition of brain and cranium.
Organs which easily expand laterally by encroachment upon their neighbors, which is a common effect of local excitement, must be slow to make any impression upon the superjacent bone of the cranium. Cranioscopy, moreover, is incompetent to indicate the development of small regions or portions of a convolution ”

“ Every care must be taken to avoid unnecessary damage of the brain-matter.
When the tumour is situated in the cerebello-pontine angle, a somewhat favourite site for tumour formation, ‘lateral displacement’ of the cerebellum towards the middle line will aid considerably in the exposure. A flat retractor, bent to a suitable curve, is introduced between the dura and the cerebellum, and the brain-matter gently but firmly retracted towards the middle line. As the brain yields to the pressure the tip of the retractor is insinuated towards the posterior surface of the petrous bone. ”

“ It has been said that we must be regulated in our proceedings very much by the existence or not of external wound; that we must be cautious in cutting down upon fractures of the cranium where there is no wound, and so converting a simple into a compound fracture. In fact, so much is the danger increased, it is alleged, by the existence of wound, that the symptoms must be very urgent indeed which would demand division of the integuments in order to admit of examination of the fracture, the application of the trephine, or the elevation of the bone ”

“ The cranial bones with the adherent dura are then pressed outward from the brain, and are either held in this position or cut through with the bone-shears so that sufficient room for the removal of the brain is afforded. The anterior falx is then cut and the brain removed as in the adult, using great care because of its very soft consistence. When too soft to be removed the brain may be opened within the skull; or a horizontal section may be made with the large, flat brain knife at the level of greatest circumference. ”

“ Unilateral cerebellar exposure. The patient being placed in the semi-prone or face-down position, the incision starts at the posterior border of the apex of the mastoid process, curves inwards along the superior curved line of the occipital bone to the occipital protuberance, and then passes straight down the middle line of the neck for 2 to 3 inches. If the incision is deepened at once to the bone, hæmorrhage is severe. The incision should first involve the skin and then the muscles attached to the occipital bone. ”

“ For this purpose the craniectomy forceps may be required. The dura can now be examined. If torn, the opening may require enlargement, in order to determine whether any osseous fragments have been driven into the brain-substance; all such fragments are carefully removed. Hæmorrhage is arrested, the dura sewn up, and the scalp-flap carefully sutured. Drainage should always be avoided, the risk of infection is too great. As a prophylactic against the development of meningeal infection, the patient should undergo the routine treatment with urotropin (see p. 116) . ”

“ Palpation may reveal the nature of the tumour, whether fluid or solid.
Exploration of the brain should only be undertaken in the light of a reasonably certain diagnosis, and every precaution must be taken [234] to avoid needless damage to the cerebral substance. The exploration should invariably be preceded by incision with the brain-knife or scalpel, introduced in such a manner as to avoid injury to all visible vessels and directed at right angles to the surface of the brain, so as to cause the least possible damage to the corona radiata, &c. ”

“ When the localization of the trouble is suggested by the presence of focal symptoms, and by a corresponding scalp- or bone-injury, no difficulty need be experienced in determining the site of exploration. When the fits are associated with definite focal symptoms, but without the supplementary evidence obtained by visible signs of external injury, exploration should be conducted over that region of the brain from which the fits appear to emanate. In the absence of all localizing brain symptoms, operative measures should be carried out over the site of scalp or bone lesion. ”

“ In cases of compound fracture, and in other conditions associated with necrosis of bone, masses of redundant granulation tissue growing from the soft parts outside the skull may simulate a hernia cerebri.
The treatment consists in counteracting the septic infection by purifying the protruding mass, and if necessary by enlarging the opening in the skull with rongeur forceps to admit of the removal of foreign bodies or bone fragments and to relieve the inter-cranial tension. Steps must also be taken to prevent meningitis, which, if it occurs, is usually fatal. ”

“ A little anatomical knowledge will prevent us from being deceived, and enable us to make due allowances. There are no great difficulties in making a correct estimate, and the anatomists who have taught their pupils that correct cranial observations could not be made, only showed their own ignorance of the subject. We must consider the cranium as though all osseous protuberances had been shaved off, leaving the smooth, curving contour of the skull. ”

“ Adults.—Sutures of skull, and those between epiphyses and shaft of long bones obliterated except that, in some mice, sutures of skull persist between frontoparietal, and interparietal; cusps of molars so worn that dentine occlusally confluent; small island of enamel in third upper and lower molars of some specimens; relative to length of skull, cranium lower, rostrum longer, and interorbital region narrower than in subadult; cranium appears to be more flattened dorsoventrally; between subadult and adult stages, principal growth occurs in basioccipital, basisphenoid, frontals, and parietals ”