The Surgery of the Skull and Brain

by Louis Bathe Rawling

SYMPTOMS RESULTING FROM FRACTURE OF THE BASE OF THE SKULL

The symptoms resulting from a fracture of the base of the skull vary according to the particular fossa fractured. From a general point of view, the following symptoms require consideration:—

Hæmorrhages.

Escape of cerebro-spinal fluid.

Escape of brain-matter.

Escape of air from the air-sinuses into the surrounding tissues.

Involvement of certain cranial nerves.

Symptoms pointing to fracture of the Anterior Fossa.

Hæmorrhages:

(a) Subconjunctival hæmorrhage

usually makes its appearance at the outer canthus of the eye, progressing inwards towards the corneo-scleral margin, and, in the most severe cases, completely surrounding the cornea, bulging the conjunctiva forwards in such a manner as to constrict the field of vision. The extravasated blood is usually bright red in colour, makes its appearance within a few hours of the accident, and reaches its maximum within thirty-six to forty-eight hours.

In some cases a condition of subconjunctival œdema (chemosis) is observed. This also usually originates at the outer canthus.

Taken by themselves, neither hæmorrhage nor œdema are of any great diagnostic value. Both conditions, however, aid materially in confirming the diagnosis.

The blood is almost invariably completely absorbed, and no ill effects remain.

(b) Palpebral and peri-palpebral hæmorrhage

is seen in most cases of fracture of the anterior fossa. This form of hæmorrhage differs from the one mentioned above in that it usually commences at the inner canthus of the eye, thence progressing in the outward direction. The extravasated blood may be wholly anterior to the suspensory ligaments of the lid, in which case it may be surmised that the fracture only involves the perpendicular plate of the frontal bone. More commonly, however, the cribriform plate of the ethmoid shares in the lesion, in which case palpebral, peri-palpebral, and subconjunctival hæmorrhage are all present.

(c) Orbital hæmorrhages

may be so extensive that marked forward protrusion of the globe exists. The time at which proptosis makes its appearance, and the degree to which it progresses, vary according to the nature of the lesion. Thus:—

Proptosis severe, appearing almost at once,	implies	a fracture associated with injury to the cavernous sinus or internal carotid artery.
Proptosis moderate, and appearing after a few hours,	„	a fracture involving the walls of the orbit, the blood being derived from lacerated ethmoidal and other small vessels.
Proptosis appearing days or weeks after the accident, usually progressive,	„	a fracture involving the region of the sphenoidal body and complicated by the formation of a fistulous communication between the cavernous sinus and the carotid artery (see [Traumatic orbital aneurysm]).

(d) Retinal hæmorrhages.

Fleming, in 1902, reported 12 cases of fracture of the skull, all except one being fractures of the base, in which retinal hæmorrhages were present. All cases were associated with hæmorrhage into the subarachnoid space, and when this hæmorrhage was of a unilateral nature the retinal changes were likewise one-sided. It was also found that in 4 cases of cerebral hæmorrhage without osseous lesion retinal hæmorrhages were present in three, these three being all associated with considerable effusion into the subarachnoid space.

These observations are not only of value in the general diagnosis of intracranial lesions, but are also of considerable importance in the differential diagnosis between extra- and intradural hæmorrhages.

(e) Hæmorrhage from the nose and mouth

is almost invariably present in fractures of the anterior fossa, with the inference that the fracture involves the cribriform plate. The blood—derived mainly from lacerated ethmoidal vessels—escapes from the anterior nares or, passing back into the naso-pharynx, escapes by the mouth or is swallowed, to be vomited up later.

Escape of cerebro-spinal fluid.

Blandin, of the Hôtel-Dieu, drew attention to this condition in the year 1840. The fracture involves the cribriform plate of the ethmoid, and is associated with laceration of the overlying dura mater and arachnoid, and of the prolongations of those membranes along the olfactory nerves.

The escape of cerebro-spinal fluid from the nose may be regarded as diagnostic of a fracture of the anterior fossa, in spite of the fact that Goucard, Malgaigne, and others describe cases in which, as the result of a severe fracture of the petrous bone (middle fossa) without laceration of the membrana tympani, the fluid escaped along the Eustachian tube to be expelled by mouth and nose.

At this stage, it will be necessary to allude more fully to the general question of cerebro-spinal discharge from the nose, mouth, and ear. The symptom is an important one, though undoubtedly of far less frequent occurrence than stated in text-books. This was proved by Crandon and Wilson, who reported 27 cases in which there was a cerebro-spinal discharge out of a total number of 530 cases examined. Phelps mentions 13 in a series of 286 cases of fractured base. My experience coincides with these statements.

The escape of a slightly blood-stained fluid from the ear and nose does not necessarily imply that the fluid is cerebro-spinal in nature, for it has been proved on numerous occasions that fluid may escape in considerable quantities without the existence of a basic fracture. In such cases the fluid is derived either from the membranous labyrinth (the liquor cotunnii) or from the mucous membrane lining the ear and nose, the result of great vaso-motor dilatation of aural and nasal vessels.

If the fluid be cerebro-spinal in nature, the natural inference is that the subarachnoid space is opened up to the exterior, either directly or indirectly along the course of a cranial nerve. A chemical analysis of the fluid will determine the nature thereof, provided that the fluid be collected EARLY.

Thus, cerebro-spinal fluid is rich in chlorides, contains little or no albumen, but shows a trace of a reducing substance, allied to pyro-catechin,

whilst

fluid derived from other sources contains chlorides, a fair amount of albumen, and no sugar.

Certain factors, however, must be taken into consideration which diminish the value of these chemical tests, for, though the fluid be cerebro-spinal in nature, the admixture of blood at once interferes with the delicacy of the test. Furthermore, even in the event of a profuse discharge of cerebro-spinal fluid, the first part collected alone contains sugar, the discharge soon becoming nothing more or less than a serous exudation.

The fluid is almost certainly cerebro-spinal if the discharge begins within twenty-four hours of the accident, if it be practically colourless, fairly profuse, and continuing for two or three days, perhaps longer.

Though the discharge usually originates early, cases are recorded in which the flow commenced some weeks after the accident. The discharge may continue for hours or for weeks. Sir W. Savory recorded a case in which fluid escaped for one month from both ears. The quantity also varies greatly, usually a few ounces, but sometimes many pints. Sir W. MacCormac recorded a case in which 10 pints escaped within five hours. A profuse discharge is due to the fact that, as the original cerebro-spinal fluid drains away, its place in the subarachnoid space is taken by a serous exudation from the cerebral venous system. This exudation occurs as soon as the subarachnoid pressure is sufficiently reduced, the serous exudation progressing till the venous and cerebro-spinal pressures are again equal.

As regards the prognosis, it is interesting to note that the escape of cerebro-spinal fluid implies of necessity that the subarachnoid space is opened up to the exterior, with all attendant dangers of meningeal infection, yet that the prognosis is generally favourable. One might even go further and state that the prognosis in such cases is rather more favourable than under more ordinary circumstances. Thus, Battle records 36 cases with a mortality of 25 per cent., the general mortality of fractured base being about 44 per cent. My own experience tallies with these statistics. The more favourable result hinges no doubt on the fact that the prolonged outflow tends to wash away organisms existent in the aural and nasal passages.

With regard to any special points in treatment, it is obvious that syringing of ear or nose is absolutely contra-indicated. The cavities should be lightly plugged with gauze, the dressings to be renewed as soon as they are soaked. The patient must also be prevented from interfering with the dressings.

With regard to the routine use of urotropin to guard against the advent of meningitis, see [p. 116].

Escape of brain-matter from the nose.

This diagnostic symptom is of very rare occurrence. For its development the following factors are requisite:—

Great comminution and destruction of the anterior fossa.

Severe local laceration of the brain (frontal lobes).

A copious discharge of blood and cerebro-spinal fluid.

A general increase in the intracranial pressure.

One case only of this nature has come under my own observation, that of a man whose right nostril was blocked with brain substance. He died shortly after admission into the hospital, and at the post-mortem examination the above conditions were found.

Escape of air from the air-sinuses into the surrounding regions.

When the fracture involves the frontal, ethmoidal, and mastoid sinuses, any sudden increase of the intrasinus air-pressure, such as is caused by sneezing, blowing of the nose, &c., may force air into the surrounding tissues. A distinction must be made between those cases in which the pericranium overlying the seat of fracture is torn and those in which it remains intact. In the former case, the escaping air may spread widely into the neighbouring loose tissues, leading to a condition of ‘surgical emphysema’. In the second case, the air remains confined to a smaller area, giving rise to a soft, more or less rounded swelling. Gentle palpation of this swelling imparts to the fingers that crackling sensation peculiar to the condition. Firm pressure results in diminution in the size of the tumour, the contained air being forced back into the sinus cavity. Such localized collections of air are known as ‘pneumatoceles’.

As regards the special treatment of these conditions, the patient must, in the first case, be warned against straining of all sorts. Pneumatoceles require no other treatment. The condition soon disappears if the patient recovers. In widespread surgical emphysema, an incision should be made over the injured sinus, thus allowing of the direct escape of the air expelled from that sinus.

The involvement of nerves.

The following nerves may be involved in anterior fossa fractures:—

(a) The olfactory nerve.

The great majority of anterior fossa fractures traverse the cribriform plate, necessarily injuring the fine branches of the olfactory bulb. The bulb itself may be lacerated, with or without injury to the under surface of the frontal lobes. Sir Prescott Hewitt considered that anosmia, or loss of smell, resulted most frequently from blows applied to the back of the head, the frontal region being injured by contre-coup. From my own experience it would appear, however, that anosmia, whether uni- or bilateral, whether transient or permanent, generally results from direct injuries of the cribriform plate with associated lacerations of the olfactory nerves. It is difficult to estimate the presence or degree of immediate loss of smell on account of the general condition of the patient and because the nostrils are usually more or less filled with blood coagulum. Experience shows, however, that early loss of smell is the rule and total and permanent anosmia the exception. Anosmia is usually associated with some degree of loss of taste.

(b) The optic nerve.

Many cases have been recorded in which visual defects resulted from blows applied to the head. The blindness may be partial or complete, immediate in onset or developing at some future date. In the latter case, the loss of vision is due to retinal changes or results from post-neuritic atrophy.

The occurrence of complete or partial blindness as the immediate result of the injury is, at first sight, difficult to explain, for the vast majority of anterior fossa fractures avoid the immediate vicinity of the optic foramina, passing by preference between the two foramina or diverging towards the sphenoidal fissures. Small fissured fractures not infrequently radiate through the optic foramina, usually, however, of so slight a nature as to be incapable of leading to any gross lesion of the optic nerves. Hæmorrhage into the sheath of the nerve is probably responsible for a certain proportion of cases, more especially those in which there is a peripheral concentric loss of vision, the more central fibres escaping. It is possible, also, that cases evidencing temporal or nasal blindness may be due, as J. J. Evans[17] thinks, to a contre-coup contusion of the nerve through it being forcibly driven against the bony boundaries of the foramen. Taking into consideration, however, the very frequent presence of a fracture through the anterior clinoid process (see [p. 82]), and the usual displacement of that process, it would appear probable that immediate and more or less complete loss of vision results from the compression and crushing of the optic nerve by reason of the pressure exercised by a displaced clinoid process.

The following statistics add confirmation to this view. Thus, Callen collected 17 cases in which the optic nerve was compressed by osseous fragments in the region of the optic foramen, whilst Holder observed injury to the bones entering into the formation of the foramen in 53 out of 86 cases of fracture involving this region.

The prognosis varies according to the cause of the blindness. When resulting from concussion of the nerve trunk or from hæmorrhage into its sheath, certain fibres may regain their function. In the majority of cases, however, that have come under my own observation, blindness of the affected eye was immediate and permanent.

(c) The nerves passing through the sphenoidal fissure.

The ophthalmic division of the fifth nerve is rarely injured to such a degree as to cause anæsthesia of all the regions supplied. Blood extravasation into the surrounding regions, or direct involvement of one of the branches of the nerve, often results in areas of anæsthesia, and some few cases have been recorded in which there was complete anæsthesia of both cornea and conjunctiva, with subsequent ulceration and sloughing. The nasal nerve may be implicated as the result of a fracture involving the cribriform plate, whilst the supra-orbital and supra-trochlear branches may be damaged by fractures of the vertical plate of the frontal bone.

The third nerve is similarly liable to injury, in any part of its orbital course. It is quite exceptional, however, for the whole trunk to be affected, some of the branches being taken, others left. The fourth nerve is also occasionally involved, generally in association with other orbital nerves.

When anæsthesia or paralysis of muscles results from pressure exercised on the nerves by extravasated blood, the ultimate prognosis is not unfavourable. When due to direct implication, in the line of the fracture, the prognosis is much more uncertain, partial or complete loss of function resulting.