The Surgery of the Skull and Brain

by Louis Bathe Rawling

FRACTURES OF THE VAULT

(a) Depressed fractures.

Depressed fractures either result from injury received during the birth of the child—whether from forceps delivery or from the pressure exerted on the head by a contracted pelvis—or from blows received shortly after birth.

Fig. 23. A Depressed Birth-fracture.

The depression, varying greatly in depth and extent, may be situated over any part of the skull, but commonly involves the fronto-parietal region. It is often obscured in the early stages by the presence of an overlying hæmatoma, the condition perhaps only being discovered after the absorption of the blood-clot. In many cases no symptoms result, partly owing to the shallowness of the depression and partly due to the situation of the lesion over one of the so-called ‘silent’ areas of the brain. Under other circumstances the child may evidence the general increase in the intracranial pressure by cyanosis, difficulty in respiration, unconsciousness, and slow pulse. The anterior fontanelle will be tense, and pulsation will be absent or greatly diminished—a feature of the greatest diagnostic value. Localizing symptoms ensue when an extensive depression is situated over the motor area, the extremities of the opposite side being flaccid, or evidencing irritation by twitchings and convulsions. The ready response of the infant to cortical irritation frequently results in the early transformation of local twitchings into general convulsions.

Course and treatment.

It is often stated that these depressed fractures remedy themselves in the course of time, the development of the underlying cortex curing the depression by the outward leverage exerted. In the minor degrees of depression there may be some chance of such spontaneous cure. I am, however, entirely opposed to the view that spontaneous cure is the rule, and there can be no question that the more severe types of depression remain as permanent defects unless surgical remedies are adopted. Furthermore, even if the deformity should cure itself in time, the intermediate dangers are not to be disregarded, for, during the process of spontaneous cure, there is a decided liability for the depressed cortex to lag behind in the process of development, or to undergo degenerative changes as the result of the pressure exerted—with disastrous results on the parts supplied by the region compressed. Mental deficiency, paralyses, and contractures will result, and there is every reason to believe that some cases of infantile paralysis are dependent on this lesion.

The following case, recently under my care, adds further proof to the statement that spontaneous cure is usually out of the question:—

The child, 10 weeks old, was admitted with a depressed fracture over the parieto-frontal region, oval in shape, and about 3¹⁄₂ inches in its long antero-posterior diameter. The centre of the depression lay about 1¹⁄₂ inches below a normal surface. The injury was produced at birth (contracted pelvis), and frequent convulsions were observed during the first few days of life. The fits then ceased, but the depression became, if anything, more marked day by day. The child was then brought up to see me. The depression was exposed by a suitable scalp-flap and a small trephine hole made immediately posterior to the depression. The dura mater was stripped away from the under surface of the bone and every effort made to remedy the depression. No impression was thus made on the defect. The whole depressed area was then cut out with a pair of scissors, the segment removed, wrapped up in a piece of gauze, and forcibly manipulated in the hope that the depression could be overcome and the segment placed back in the normal position. This attempt was also greeted with failure. The segment was then placed back in the inverted position, the dural surface external and vice versa. The segment required some trimming with the scissors before it fitted accurately in position. The scalp-flap was then replaced. The child suffered but very slightly from the operation, firm union was present in two weeks, and, six months later, examination of the skull showed that the two sides were absolutely symmetrical.

It should be noted that, although the child was only 10 weeks old, and in spite of the fact that the depression was fully exposed, it was quite impossible to lever up the depressed bone. This hardly coincides with the views of those who maintain that birth-depressions undergo spontaneous cure.

Taking all these facts into consideration, it would appear advisable to adopt the following course:—slight depressions, situated in the region of ‘silent’ areas of the brain, may be left for one or two weeks, and, in the event of failure at spontaneous cure, the depression must be elevated. In all the more serious cases, whether associated with symptoms of brain-pressure or not, surgical interference is imperative.

A

B

Fig. 24. A Case of Depressed Birth-fracture. A, Before operation; B, After operation. (For further description, see text.)

Operation.

The baby would be well wrapped up and, after shaving and cleansing of the scalp, the scalp-tourniquet applied. Babies stand these operations exceedingly well so long as hæmorrhage is but slight. A scalp-flap is turned down and a small trephine (¹⁄₂-inch diameter) applied immediately to one side of the depression, the trephine circle including the outer margin of the depressed area. The dura is stripped away and a flat periosteal elevator introduced so that its apex corresponds to the apex of the depression. An attempt is then made to lever the depressed area in the outward direction. If that result be attained, well and good. The flap is replaced and dressings applied. In many cases, however, the elevated region promptly assumes its original depressed position as soon as the elevator is removed, and, in other cases, all attempts at rectification of the deformity are of no avail. Under these circumstances, it is advisable to carry out the method advocated by Nicholl—adopted in the case described above—the whole of the depressed area being cut out with blunt-pointed scissors, reduced to a more normal curvature by manipulation between layers of gauze, and replaced in the inverted position, the original dural surface becoming now external. This inversion is requisite, as it is usually quite impossible—even under considerable pressure—to reduce the depression to a permanently satisfactory degree.

Nicholl reports on 23 cases, the ages of the patients varying from 3 weeks to 8 years. The first 13 cases were treated by elevation. The results obtained were most unsatisfactory, complete reduction of the deformity seldom being attained, whilst recurrence, of a greater or lesser degree, was the rule.

In the last 10 cases the inversion method was carried out, with, in all cases, satisfactory results. Bony union was present in 10 days.

Four cases of depressed birth-fractures have come under my own care. In two cases the depression was elevated—in both cases with considerable difficulty—whilst in the other two cases, after failure of leverage, Nicholl’s method was carried out, in both cases with eminently satisfactory results.

(b) Fissured fractures.

Fissured fractures are especially prone to involve the parietal bone, and, in their direction, to follow the lines of ossification. Thus, in the case of the parietal bone, the fissures will radiate from the parietal prominence. There is also a certain tendency for the fracture to remain limited to the particular bone affected.

The presence and extent of the fracture is commonly obscured by the overlying hæmatoma, which is either subpericranial or subaponeurotic. On the other hand, the hæmatoma may, from its size and shape, supply evidence as to the nature of the underlying lesion. Thus, when confined to the parietal bone, it may be inferred that the fracture is also limited to that region. Again, when linear, the presumption is that the fracture is of a similar nature. A definite diagnosis may be impossible without aspiration or till after absorption of the hæmatoma. The fissure will then be found to vary in extent from a mere crack in the bone to a wide gap as broad or broader than the width of the finger. In a case recently under my care the fissure, over half an inch in breadth, extended from the vertex to the base, whilst throughout the whole extent of the gap pulsation was readily obtained.

Fissured fractures in the very young possess another point of interest in that the cleft often tends to increase, this being notably the case when the fracture is associated with injury to underlying dura and brain. The local and general increase of intracranial pressure not only widens the gap, but also leads to thinning and eversion of the margins of the deficiency with possible herniation of brain-matter—traumatic cephalocele.

Symptoms.

In many cases—in spite of the severity of the lesion—there are no symptoms, the child appearing but little the worse for the accident. In most cases, however, the child evidences symptoms of brain-concussion, irritation, or compression, for which conditions reference should be made to the sections dealing with those subjects.

It should be noted, however, that the anterior fontanelle supplies evidence as to increase or decrease of intracranial pressure. In concussion the fontanelle is depressed, in compression it is tense and pulsation is absent or diminished. Irritation of the brain is evidenced by irritability and general convulsions.

Treatment.

In the absence of symptoms, or when the fracture is associated with concussion or irritation, operative measures are contra-indicated, the patient being treated after the general principles laid down for those conditions.

When associated with symptoms of brain-compression, exploration is almost always advisable, the scalp-tourniquet being applied and the injured region exposed by a suitable scalp-flap. Depressed bone is elevated, or the trephine applied so as to fully expose the underlying dura mater. A bulging, non-pulsatile, and plum-coloured membrane points to the existence of a subdural hæmatoma. The membrane is then incised and the clot evacuated. Whenever possible the dura mater should be sewn up and the scalp-flap replaced without drainage.

Operative measures are also indicated when a linear fracture gapes widely—especially when the gap shows a tendency to increase in width. The steps of such an operation are as follows:—

1. Expose the fracture throughout its whole length.

2. Cut away all pericranium or fibrous tissue that intervenes between the margins of the cleft.

3. Separate the dura mater from the bone on either side of the cleft for a distance of about ¹⁄₂ inch, at the same time sewing up any rents in the membrane.

4. Bore a few holes through the skull—using an ordinary bradawl—on either side of the cleft, the holes being placed about ¹⁄₂ inch apart.

5. Approximate and lace the margins of the cleft by means of fine silver wire or strong catgut.

6. Sew up the flap without drainage.