«FRACTURES OF THE ANTERIOR FOSSA OF THE SKULL Lecture delivered at the Royal College of Surgeons of England on 22nd April, 1952 by Wylie McKissock, ...»
FRACTURES OF THE ANTERIOR FOSSA OF THE SKULL
Lecture delivered at the Royal College of Surgeons of England
22nd April, 1952
Wylie McKissock, O.B.E., F.R.C.S.
Surgeon, National Hospital, Queen Square, London
FAR TOO MUCH weight has been- attached in the past to the presence of a
fracture of the skull. A mere linear fracture of the vault or base is of no
importance in assessing the degree of temporary or permanent damage to
the individual concerned. Only when such a fracture involves other structures do more sinister implications arise and in the anterior fossa of the skull there are many opportunities for this to occur.
First, a fracture of the vault or base may encroach upon the frontal or ethmoidal accessory nasal sinuses. How dangerous this may be depends upon whether or not the covering membranes of the brain have been torn.
If the membranes are torn then there exists a channel for the exit of macerated brain or of cerebro-spinal fluid to the outside world and thus for the entry of infection from the external air through the air sinuses.
The potential complications in'such a case are therefore (1) Infection.
(2) Cerebrospinal fluid rhinorrhoea.
These conditions are all grave ones, even in these days of the sul- phonamides and antibiotics, calling for immediate prophylaxis and active treatment.
In the case of a patient suspected of having a fracture of the anterior fossa involving the frontal or ethmoidal sinuses, careful radiological examination by a trained neuroradiologist will be necessary to demon- strate the exact site and nature of fracture. This is of great importance, for the degree of damage to brain or its covering membranes can usually be quite accurately assessed if a complete picture of the fracture can be obtained. If, for example, the fracture is only a linear crack crossing the territory of a nasal sinus with no displacement of the bone edges, the likelihood of there being serious brain damage is small. On the other hand if a flake of the thin orbital roof can be seen grossly tilted out of position it is certain that the dura and arachnoid have been ruptured and the sub- jacent brain lacerated. Such points are of great value in treatment and for prognostic purposes.
The presence of cerebro-spinal fluid rhinorrhoea clinically proves the presence of a fracture involving the nasal sinuses even if, as is somethimes the case, no radiological evidence of fracture is forthcoming. The neces- sary radiological examination of such cases will also reveal the presence of air within the cranial cavity either in the subarachnoid space, the brain substance itself (aerocoele), or, rarely, in the ventricular system (trau- matic ventriculogram).
FRACTURES OF THE ANTERIOR FOSSA OF THE SKULL
Lateral radiogram of skull showing small localised depressed fracture of frontal bone involving frontal sinus.
FRACTURES OF THE ANTERIOR FOSSA OF THE SKULLSuch abnormalities can be caused either at the moment of injury or later, usually as a result of the patient attempting to blow the nose. The rise of pressure in the nasal cavities attending nose blowing can force air and nasal secretions through the fracture line into the intracranial cavity.
If the pressure is great enough air can be forced through the brain substance and secondarily into the ventricles. Such a sudden occurrence is followed usually by severe headache from the attendant rise of intracranial pressure, the rapid development of additional neurological signs or even by unconsciousness.
Alternatively the development of an aerocoele may occur at the time of the injury and be discovered accidentally when routine radiograms of the skull are taken. The presence of air inside the membranous coverings is a most dangerous one with great attendant risks of an intracranial infection either in the form of a septic leptomeningitis or of brain abscess.
Fractures of the anterior fossa can also be responsible for damage to one or more of the cranial nerves. Probably the most common complication of a fracture of this kind is damage to the olfactory tracts as they run back from the cribriform plate. Complete rupture or partial tearing may occur in the former case resulting in permanent unilateral or bilateral anosmia with consequent impairment of sense of taste. If the tracts are damaged, partial recovery of sense of smell may take place, but also unfortunately the condition of parosmia may develop in which the patient is constantly aware of an unpleasant odour. This may remain permanently, whilst in other cases it may last for a few months and then disappear.
The optic nerves are occasionally involved in fracture of the anterior fossa usually as a sequel to fractures involving the optic foramen with direct compression or tearing of the nerve, leading to permanent blindness in that eye. Rarely a fracture may involve the optic foramen without damage to the nerve, which months later becomes involved either by pressure from callus or fibrosis strangling the blood supply. Clinically this leads to gradual failure of vision in the affected eye associated with increasing pallor of the disc.
The third, fourth and sixth intracranial nerves may be damaged or torn by fractures extending into the sphenoidal fissure with associated narrowing of the fissure and compression of the nerves.
The clinical picture is infinitely variable from complete intra- and extraocular muscular palsy to minor disturbances of a particular muscle.
Little if any recovery is to be expected in severe bony injuries of the sphenoidal fissure, but in minor cases good compensation for the slighter injuries may confidently be expected.
The trigeminal nerve can also be damaged at the level of the sphenoidal fissure so far as its first division is concerned but the supra-orbital nerve is most commonly injured at the level of the supra-orbital notch or foramen at the superior margin of the orbit. Complete tearing from a serious fracture with displacement of fragments results in a small area of anaesthesia over the central forehead extending upwards for a variable 221 18-2
WYLIE MCKISSOCKdistance towards the vertex. When the nerve is only damaged unpleasant paraesthesiae may develop later as regeneration of the nerve takes place. Occasionally the supra-orbital nerve becomes embedded in scar tissue with the production of severe neuralgia in its area of distribution.
The roof of the orbit being very thin it is frequently displaced in anterior skull fractures. It may be broken into small fragments, grossly depressed or angulated in such a way as to cause serious laceration of the overlying membranes and frontal lobe. Apart altogether from associated damage to the sphenoidal fissure with lesions of the third, fourth and sixth nerves, serious damage to orbital contents may result from depressions of the orbital roof. Proptosis of the eye will be evident together with defective co-ordination of the extra-ocular muscles and consequent diplopia which may be mild or crippling. Lesser degrees of damage may be expected to resolve spontaneously with time, but severe disturbance of ocular movement may remain permanently.
So far the fractures and injuries described have been peculiar to the anterior fossa, but those fractures occurring elsewhere over the vault of the skull are also common in front of the coronal suture. All degrees of injury are common, from simple fissure without neurological complication, to extensive depressed fractures associated with tearing and laceration of the covering membranes and pulping of the subjacent brain. Focal neurological signs will not be forthcoming with such lesions of the anterior part of the vault, but later sequelae in the form of traumatic epilepsy or chronic brain abscess are all too common, especially where early definitive treatment has not been applied.
TREATMENT The general care of patients with fractures involving the anterior fossa of the skull differs in no way from that of other head injuries.
Any external wound should be powdered with sulphanilamide and covered with a full head-dress, no attempt being made to clean the wound or shave the surrounding scalp. Such measures are held over until the complete surgical treatment of the wound is to be undertaken.
Rest in bed, preferably in the sitting position which aids in lowering the intracranial pressure, warmth and free allowance of sustaining fluids together with penicillin and sulphonamides should be the regime for the first 24 hours following the injury. During this period as complete an examination of the central nervous system as the patient's condition and co-operation will permit should be carried out to provide a base line from which to infer the nature and extent of the initial injury and the degree of recovery eventually achieved. If fluid is running from the nose a specimen should be obtained so that the presence or not of a cerebrospinal fluid leak can be established with certainty by laboratory tests for sugar.
FRACTURES OF THE ANTERIOR FOSSA OF THE SKULLAt the end of the first 24 hour'period, if the condition of the patient is reasonably good, a thorough radiological examination of the skull should be made and by this is meant a planned investigation and not the taking, by a radiographer, of a routine series of radiograms. The neuroradiologist of the X-ray department should be supplied with all relevant details concerning the circumstances of the injury, the neurological signs and the presence or not of a bloody discharge from nose or ears. It is for the neuroradiologist to decide which projections should be made and what additional views of the skull are necessary, and the patient should remain in the radiological department until the radiologist is satisfied that he has obtained the fullest details possible of the bony injuries present.
Such a thorough examination may put a considerable strain upon the injured patient and one of the reasons why this examination should be delayed for some hours is to allow the patient some time to recuperate.
Early X-ray examination may harm the patient if carried out thoroughly and, alternatively, there is nothing so futile or uneconomic as an inadequate set of radiograms which may well fail to reveal a bony injury or give inadequate information concerning it.
One example will suffice to emphasize the need for the presence of the neuroradiologist. The standard set of skull plates has been taken and no obvious fracture has been seen but behind the frontal sinus in a horizontal lateral view of the skull there is a dark thin shadow which might well be air within the cranial cavity. The neuroradiologist on viewing the wet films will at once reposition the head and see whether the shadow moves: if it does the presence of a fracture is proved even if it does not show in the films. If the air moves freely it must lie in the subarachnoid space and hence a penetrating injury exists with all its attendant dangers of infection. If the shadow moves only slightly it probably indicates air in the extradural space and may well mean that the covering membranes have not been disrupted. Should no neuroradiologist be available the supervision of the radiography must be done by the neurosurgeon himself: it should not be left to the general radiologist and certainly not to a radiographer.
Once the radiological investigation has been concluded and the evidence of bony injury considered in relation to the clinical state, the desirability of lumbar puncture can be assessed.
Lumbar puncture can give valuable information in one or all of three ways, the pressure, the presence of blood and of cellular reaction indicating infection.
Lumbar puncture is contra-indicated if there is cerebro-spinal fluid discharging from nose or ear and if there is an obvious open wound communicating with the intracranial cavity. In these two conditions the pressure reading will be invalidated by leakage and it may confidently be assumed that blood will be present as an indication of brain trauma: the risk of infection is obvious and the appropriate treatment with antibiotics and sulphur drugs has already been started.
WYLIE MCKISSOCKIf, however, there is evidence of fracture without penetration of dura, pia arachnoid or brain,.lumbar puncture should be performed, the pressure measured and the fluid examined. High pressure or the presence of blood indicating brain damage will be of assistance in estimating the degree and time of recovery.
Surgical Treatment is now possessed of all the necessary information The neurosurgeon which will enable him to give the appropriate treatment or plan an operation. If there is an open wound with or without underlying fracture, surgical intervention is inevitable and should be carried out under proper neurosurgical conditions, even when there is no breach of the skull and the wound only involves the scalp. The practice of suturing scalp wounds in a casualty or out patient department cannot be too greatly deplored.
The incidence of infection is high and every now and again complications such as osteomyelitis of the skull will result with a grave, if not fatal, outcome. Scalp wounds closed in this way are never healed in 48 hours as are those closed in two layers after proper excision in the routine neurosurgical manner.
In most compound or open fractures of the vault or anterior fossa excision of the wound can usually be achieved through the traumatic wound or extensions of it, but those in which extensive damage has been done to accessory nasal sinuses are probably best attacked through a scalp flap of one kind or another. In the case of very small external wounds produced by high velocity projections with severe damage beneath, the approach through a scalp flap should always be used. There should be in the surgeon's mind two aims which he must achieve, i.e., to remove all dead or damaged tissue and to produce watertight closure of the dura mater after excision of the wound. Many surgeons err with the best intentions when they deliberately leave large separated bone fragments behind in regions such as the forehead, glabella and supra-orbital ridges.