Manual of Surgery Volume II Part 37

_Bullet wounds_ have many features in common with punctured wounds.

There is more contusion of the brain substance, disintegrated brain matter is usually found in the wound of entrance, and the bullet often carries in with it pieces of bone, cloth, or wad, thus adding to the risk of infection.

Aseptic foreign bodies, especially bullets, may remain embedded in the brain without producing symptoms.

The _treatment_ of punctured wounds consists in enlarging the wounds in the soft parts, trephining the skull, and removing any foreign body that may be in it, purifying the track, and establishing drainage.

AFTER-EFFECTS OF HEAD INJURIES

Various after-effects may follow injuries of the head. Thus, for example, _chronic interst.i.tial changes_ (sclerosis) may spread from an area of cicatrisation in the brain; or _softening_ may ensue, either in the form of pale areas of necrosis (white softening) or of haemorrhagic patches (red softening). The symptoms vary with the area implicated. _Adhesions_ between the brain and its membranes may produce severe headache and attacks of vertigo, especially on the patient making sudden exertion.

After a head injury, the patient's whole mental att.i.tude is sometimes changed, so that he becomes irritable, unstable, and incapacitated for brain-work--_traumatic neurasthenia_. In some cases self-control is lost, and alcoholic and drug habits are developed.

#Traumatic epilepsy# may ensue as a result of some circ.u.mscribed cortical lesion, such as a spicule of bone projecting into the cortex, the presence of adhesions between the membranes and the brain, a cicatrix in the brain tissue leading to sclerosis or a haemorrhagic cyst in the membranes or cerebral tissue.

The convulsive attacks are of the Jacksonian type, beginning in one particular group of muscles and spreading to neighbouring groups till all the muscles of the body may be affected. The convulsions may begin soon after the injury, for example, when the cause is a fragment of bone irritating the cortex; in other cases it may be several years before they make their appearance. The onset is usually sudden, and the "signal symptom"--for example, jerking of the thumb, conjugate deviation of the eyes, or motor aphasia--indicates the seat of the lesion. At first the attacks only recur at intervals of, it may be weeks or months, but as time goes on they become more and more frequent, until there may be as many as forty or fifty in a day.

Sometimes the patient loses consciousness during the fit; sometimes he remains partly conscious. In course of time the same degenerative changes as occur in other forms of epilepsy ensue: certain groups of muscles may become paralysed; the patient may pa.s.s into a state of idiocy, or into what is known as the "status epilepticus," in which the fits succeed one another without remission, the breathing becomes stertorous, the temperature rising, the pulse becoming very rapid; finally coma supervenes, and the patient dies.

_Treatment._--The administration of bromides is only palliative.

Operation is indicated only when the "signal symptom" indicates a limited and accessible portion of the brain as the seat of the lesion, or when there is a depression of the skull or other definite evidence of cranial injury. The more recent the injury the better is the prospect, as secondary changes are less likely to have taken place, and the peculiarly irritable state of the brain--sometimes referred to as the "epileptic habit"--has not developed. The operation consists in opening the skull freely, and removing any discoverable cause of irritation--depressed bone, thickened and adherent membranes, a cyst, or sclerosed patch of cortex; it may be necessary to interpose a layer of tissue, a flap of fascia lata, for example, between the bone and the cortex of the brain. The point at which the skull is opened is determined by the seat of the injury and the focal brain symptoms.

The return of fits within a few days of the operation does not necessarily mean failure, as they often pa.s.s off again. Complete and permanent cure is not common, but the number and severity of the attacks are usually so far diminished that life is rendered bearable.

#Traumatic insanity# may follow injury to any part of the brain, and it may come on either immediately or after an interval. It may or may not be a.s.sociated with epilepsy. Any form of insanity may occur, either as a direct result of the trauma, or from the resistance of the brain being lowered by the injury in a patient predisposed to insanity. When insanity follows as a direct consequence of injury, the organic lesion is usually a superficial one, and the disturbance of brain function is generally due to reflex irritation of the dura mater (Duret). These facts possibly explain the immediate improvement which occasionally follows the opening of the skull at the point of injury and removal of the exciting cause. Cases occurring within a few days of the injury usually recover within a month or two. The later the condition is in developing the less obvious is the relationship between the trauma and the insanity, and therefore the worse is the prognosis.

_Meningitis_, _sinus thrombosis_, and _cerebral abscess_ may follow upon any form of head injury attended with infection. The clinical features--save for the history of a trauma--correspond so closely with those of the same conditions occurring apart from injury, that they are most conveniently considered together (p. 374).

CHAPTER XIII

INJURIES OF THE SKULL

Contusions--FRACTURES--Of the vault: _Varieties_--Of the Base: _Anterior fossa_--_Middle fossa_--_Posterior fossa_.

The bones of the skull may be contused or fractured. These injuries are not in themselves serious: their clinical importance is derived from the injury to the intra-cranial contents with which they are liable to be a.s.sociated.

#Contusion# of the skull may result from a fall, a blow, or a gun-shot injury. In the majority of cases the damage to soft parts--scalp, meningeal vessels, or brain--overshadows the osseous lesion, which of itself is comparatively unimportant.

FRACTURES OF THE SKULL

While it is convenient to consider separately fractures of the vault and fractures of the base of the skull, it is to be borne in mind that it is not uncommon for a fracture to involve both the vault and the base. Fractures in either situation may be simple or compound.

FRACTURES OF THE VAULT

#Mechanism.#--When the skull is broken by _direct_ violence, the fracture takes place at the seat of impact, and its extent varies with the nature of the impinging object and the degree of violence exerted.

If, for example, a pointed instrument, such as a bayonet, a foil, or a spike, is forcibly driven against the skull, the weapon simply crashes through the bone, disintegrating it at the point of entrance, and cracking or splintering it for a variable, but limited, distance beyond. On the other hand, when the head is struck by a "blunt"

object--for example, a batten falling from a height--the force is applied over a wider area and the elastic skull bends before it. If the limits of its elasticity are not exceeded, the bone recoils into its normal position when the force ceases to act; but if the bone is bent beyond the point from which it can recoil, a fracture takes place--"_fracture by bending_." The bone gives way over a wide area, the affected portion may be comminuted, and one or more of the fragments may remain depressed below the level of the rest of the skull. Cracks and fissures spread widely in different directions--often (70 to 75 per cent.) extending into the base. In almost all fractures of the vault the inner table splinters over a wider area than the outer, partly because it is more brittle and is not supported from within, but also because the diffusion of the force as it pa.s.ses inwards affects a wider area. If a bullet traverses the cranial cavity the inner table is more widely shattered at the aperture of entrance, and the outer table at the aperture of exit. Von Bergmann reported thirty cases in which the inner table alone was fractured by a blow on the head.

Fractures by _indirect_ violence--that is, fractures in which the bone breaks at a point other than the seat of impact--are almost always due to violence inflicted with a blunt object, and acting over a wide area--such, for example, as when the head strikes the pavement. Much discussion has taken place as to the method of their production. It has been shown that when the skull is depressed at one point by a force impinging on it, it bulges at another, so that its whole contour is altered. But the elasticity of the bone varies at different parts of the skull, owing to differences in thickness and in structure. If, therefore, the part which is depressed--that is, the part directly struck--happens to be less elastic than the part which bulges, it gives way, and a fracture by "bending" results; but if the bulging part is the less elastic, it bursts outwards--_fracture by_ "_bursting_." The term "fracture by _contre-coup_" has been incorrectly applied to such fractures when the area of bulging happens to be opposite to the seat of impact. _Contre-coup_, properly so-called, is only possible in a perfectly spherical body, which, of course, the skull is not.

When a high-velocity bullet penetrates the head, it exerts on the incompressible, semi-fluid brain an explosive (hydro-dynamic) force, which is transmitted to all points on the inner surface of the skull and leads to shattering of the bone.

_Repair._--The repair of fractures of the skull is usually attended with an exceedingly small amount of callus. Except in the presence of infection, separated fragments live and become reunited, but they may unite in such a manner as to project towards the brain and, by irritating the cortical centres, cause traumatic epilepsy. In comminuted fractures, the lines of fracture remain permanently visible on the bone, but fissured fractures may leave no trace. Gaps left in the skull by injury or operation are, after a time, filled in by a fibrous membrane, which may undergo ossification from the periphery towards the centre, but unless the aperture is a small one it is seldom completely closed by bone. The new bone which forms is derived from the old bone at the margins of the opening. Permanent defects in the skull are chiefly injurious if they are accompanied by lesions of the underlying dura, such as adhesions to the brain; large gaps may cause giddiness on stooping, or on forcible expiration, as in blowing the nose or playing a wind instrument.

#Varieties.#--For descriptive purposes, fractures of the vault are divided into the fissured, the punctured, the depressed, and the comminuted varieties. Clinically, however, these varieties are often combined. The practical importance of a given fracture depends upon whether it is simple or compound, rather than upon the exact nature of the damage done to the bone. Compound fractures which open the dura mater are the most serious. Simple fractures result, as a rule, from diffuse forms of violence, and are liable to spread far beyond the seat of impact. Compound fractures result from severe and localised violence--for example, the kick of a horse or the blow of a hammer--and tend to be limited more or less to the seat of impact. In gun-shot injuries, however, there are usually numerous fissures radiating from the point at which the missile enters the skull.

#Fissured fractures# generally result from blows by blunt objects or from falls, and they usually extend far beyond the area struck, in most cases pa.s.sing into the base. The fissure may pa.s.s through the bone vertically or obliquely, and it may implicate one or both tables.

So long as the fracture is simple, it can scarcely be diagnosed except by inference from the a.s.sociated symptoms of meningeal or cerebral injury. When compound, the crack in the bone can be seen and felt. It is recognised by the eye as a split in the bone, filled with red blood, which, as often as it is sponged away, oozes again into the gap. In fractures by bursting a tuft of hair may be caught between the edges of the fracture, and this adds to the difficulty of purifying the wound.

_Diagnosis._--A normal suture may be mistaken for a fissured fracture.

A suture, however, may generally be recognised by its position, the irregularity of its margins, and the absence of blood between its edges. At the same time, it is not uncommon, especially in children, for a suture to be sprung by violence applied to the head, or for a fissured fracture to enter a suture and, after running in it for some distance, to leave it again. The edges of a clean cut in the periosteum may be mistaken for a fissure in the bone, especially if reliance is placed on the probe for diagnosis. This error can be avoided by raising the edge of the periosteum from the bone, with the gloved finger. On combined auscultation and percussion a peculiar "hollow-cask" sound may be detected in some cases of fissured fracture of the vault.

Fissured fractures as such call for no _treatment_. When compound, the wound must be disinfected; and intra-cranial complications, such as meningeal haemorrhage, laceration of the brain, or infection, are to be treated on the lines already described.

#Punctured fractures# are of necessity compound, and on account of the risks of infection are to be looked upon as serious injuries. They result from the localised impact of a sharp, and usually infected object the point of which is not infrequently left either in the bone or inside the skull. Fragments of bone are often driven into the brain, and short fissures frequently pa.s.s in various directions from the central aperture.

_Diagnosis._--When the instrument impinges on the head obliquely, after piercing the scalp it may pa.s.s for some distance under it before perforating the skull, so that on its withdrawal a valvular wound is left, and at first sight it appears that only the scalp is involved.

Sometimes a foreign body left in the gap so fills it up that it is difficult to detect the fracture with a probe or even with the finger.

In all doubtful cases the scalp wound should be sufficiently enlarged to exclude such errors. We have known of a case of a man who died of meningitis resulting from a punctured fracture of the vault caused by the spoke of an umbrella, the fracture having escaped recognition until the meningeal symptoms developed.

_Treatment._--The scalp wound must be purified, being opened up as far as necessary for this purpose. The infected portion of bone should be removed to render possible the purification of the membranes and brain, and to permit of drainage.

#Depressed and Comminuted Fractures.#--As these varieties almost always occur in combination, they are best considered together. The terms "indentation fracture," "gutter fracture," "pond fracture," have been applied to different forms of depressed fracture, according to the degree of damage to the bone and the disposition of the fragments (Figs. 188, 189, 190). These fractures may be simple or compound.

[Ill.u.s.tration: FIG. 188.--Depressed Fracture of Frontal Bones--involving the air sinus on both sides--with a fissured fracture radiating from it.

(From Professor Harvey Littlejohn's collection.)]

[Ill.u.s.tration: FIG. 189.--Depressed and Comminuted Fracture of Right Parietal Bone: Pond Fracture. The patient sustained the injury twenty years before death.]

[Ill.u.s.tration: FIG. 190.--Pond Fracture of Left Frontal Bone, produced during delivery.

(From a photograph lent by Mr. J. H. Nicoll.)]

As a rule the whole thickness of the skull is broken, and, as usual, the inner table suffers most. In infants the bones may be merely indented, the fracture being of the greenstick variety. All degrees of severity are met with, from a simple, localised indentation of the bone, to complete smashing of the skull into fragments.

_Diagnosis._--When compound, the nature of these fractures is readily recognised on exploring the wound, but their extent is not always easy to determine, and it is not uncommon for extensive fissures to pa.s.s into the base.

A haematoma of the scalp may readily be mistaken for a depressed fracture. The condensation of the tissues round the seat of impact and the soft coagulum in the centre, closely simulate a depression in the bone; but if firm pressure is made with the finger, the irregular edge of the bone can be recognised, and the depressed portion is felt to be on a lower level. On the other hand, a depression in the bone is sometimes obscured by an overlying haematoma, and unless great care is taken the fracture may be overlooked.

_Treatment._--All are agreed that compound depressed and comminuted fractures--whether a.s.sociated with cerebral symptoms or not--should be operated on to enable the wound to be purified, and the normal outline of the skull to be restored by elevating or removing depressed or separated fragments. Except in young children, in whom considerable degrees of depression are frequently righted by nature, most surgeons recommend operative interference even in simple fractures with the object of elevating the depressed bone, and to antic.i.p.ate subsequent complications such as persistent headache, attacks of giddiness, traumatic epilepsy, or insanity. Others, including von Bergmann and Tilmanns, consider that the risk of such sequelae ensuing is not sufficient to justify a prophylactic operation of such severity as trephining.

The operation is described in _Operative Surgery_, p. 93.