Fig. 49a. The Elevation of a Depressed Fracture. First stage. The trephine circle includes the outer portion of the depressed area.
Fig. 49b. The Elevation of a Depressed Fracture. Second stage. The trephine disk has been removed and the elevator is in position.
With respect to compound fractures, it is necessary that the bone lesion should be fully exposed, all pockets of scalp-tissue being slit up to their termination. Previous to any attempt at examination of the injured bone, further precautions must be taken to avoid subsequent infection, by reason of the bruised and soiled scalp. Such tags of scalp-tissue as appear injured beyond repair should be cut away with the scissors, and in order to avoid or diminish subsequent wound infection, I have been accustomed to swab over the most suspicious parts with pure carbolic acid, washing away the same with saline solution. Since the advent of iodine sterilization, I have often utilized that solution in preference to the carbolic, swabbing the whole surface exposed. I think a combination of the two methods is advisable in more serious cases, utilizing the carbolic for the margins of the wound and iodine for the general surface. By means of this method the risk of meningeal infection and scalp suppuration is greatly reduced. To aid in the prophylaxis, the patient should again be placed under a course of treatment by urotropin (see p. 116).
With regard to the bone, all loose fragments should be removed, only those being preserved which retain their pericranial connexions. Even these are thrown back so as to permit of the maximum inspection of the dura mater. This membrane, if torn, is either sewn up at once or opened up more freely in the investigation and removal of underlying blood-clot or bone-débris. After removing such troubles the membrane is accurately sutured. The bone-flaps are now replaced in position. Some surgeons advocate the replacement of the smaller fragments of bone which have previously been removed. These fragments may be sterilized by boiling, but such a process destroys the bone-cells and, in consequence, they become absorbed, merely acting as scaffolding media for the formation of fibrous tissue. Added to that, in the event of suppuration, the presence of such fragments not only leads to the persistence of a purulent discharge, till the fragments are entirely removed, but also increases considerably the risk of meningeal infection.
As a summary, therefore, it may be laid down that it is necessary to remove all loose fragments of bone, the deficiency in the vault being rectified, if necessary, at a later date by one of the methods enumerated in Chapter VI.
The scalp-flap is accurately sewn up with interrupted salmon-gut sutures, a gauze or cigarette drain being inserted at the most convenient and dependent point, to be removed at the end of forty-eight hours or more according to the progress of the case.
Here there is a special liability to dural laceration and in-driving of comminuted fragments of bone. A full exposure of the parts is therefore absolutely essential. The trephine can be applied in the immediate vicinity of the puncture, or, as is often advisable, in such a manner that the punctured area is included in the trephine circle: this latter method may necessitate that the trephining should be carried out without the aid of the guiding fixation-pin, for which process some experience is needed.
After removal of the bone, the craniectomy forceps may be required, to allow of adequate dural inspection. The dura mater is opened up with blunt-pointed scissors, and the brain examined for in-driven fragments of bone. These, when found, are removed. Deeply situated fragments of bone and foreign bodies may be previously diagnosed by means of an X-ray picture.
If possible, both membrane and scalp should be sutured without drainage, but in the event of possible sepsis, a small cigarette drainage-tube should be inserted so as to lie beneath the dura mater on the one hand and emerge through the scalp wound at the other.
For this class of fracture the reader is referred to the section dealing with bullet-wounds of the skull (see p. 296).
As previously indicated, the diagnosis of this condition is only practicable when the depression of the osseous fragments, or the hæmorrhage resulting from an injured meningeal vessel, so irritate the dura mater and brain that localizing symptoms ensue. For instance, epileptic fits of a Jacksonian type may develop shortly after the accident, this condition demanding a full exposure of the affected region. The operations required in the treatment of traumatic epilepsy and intracranial hæmorrhages are discussed in subsequent chapters.
Whatever the nature of the osseous lesion, the mortality is almost entirely dependent on the question of associated injury to the intracranial contents, more especially the brain.
In the case of fractures purely or mainly basic, of the cases that have come under my care or observation, 116 recovered and 89 died—a mortality of 44 per cent.
Battle, from an examination of 168 cases, puts the mortality at the low figure of 32 per cent., whilst Crandon and Wilson, from an exhaustive series of 530 cases, estimates it at 44 per cent.
The mortality varies according to the age of the patient, the death-rate being at its maximum at the two extremes of life—between 50 and 60 per cent. under the age of 5 years and over 60 per cent. after the age of 70.
The mortality varies also according to the fossa implicated. Thus, to each fossa there are certain peculiar dangers—to the anterior fossa, meningeal infection from the nose, frontal and ethmoidal sinuses; to the middle fossa, meningeal infection from the naso-pharynx and ear, and hæmorrhage from the middle meningeal and internal carotid arteries, and from the cavernous venous sinus; and to the posterior fossa, laceration of the lateral and sigmoid venous sinuses.
After such consideration of local complications, it would appear that the middle fossa of the skull presents the greatest dangers. Another factor must, however, be taken into consideration—injury to the brain—the commonest cause of death in all head injuries. The main vital centres are grouped in the region of the fourth ventricle, and Leonard Hill has proved that any increase in the intracranial pressure exerts its influence most rapidly and most effectually when the lesion is situated beneath the tentorium cerebelli.
One may assume, therefore, that fractures of the posterior fossa are the most dangerous, and that those involving the anterior fossa hold out the best prognosis.
In the case of pure or primary vault fractures the mortality may be estimated by reference to the following table. It is composed from 88 cases admitted into St. Bartholomew’s Hospital between the years 1900 and 1906.
| Under the | age of | 5 | 8 | lived | and | 2 | died. | Mortality, | 20 | per | cent. |
| „ | „ | 10 | 2 | „ | „ | 3 | „ | „ | 60 | „ | |
| „ | „ | 15 | 6 | „ | „ | 0 | „ | „ | 0 | „ | |
| „ | „ | 20 | 10 | „ | „ | 3 | „ | „ | 23 | „ | |
| „ | „ | 30 | 9 | „ | „ | 1 | „ | „ | 10 | „ | |
| „ | „ | 40 | 16 | „ | „ | 9 | „ | „ | 36 | „ | |
| „ | „ | 50 | 3 | „ | „ | 7 | „ | „ | 70 | „ | |
| „ | „ | 60 | 2 | „ | „ | 1 | „ | „ | 33 | „ | |
| Over the age of | 60 | 3 | „ | „ | 3 | „ | „ | 50 | „ | ||
| 59 | lived | and | 29 | died. | Mortality, | 37 | per | cent. | |||
For the remote effects of skull fractures, see Chapter VI.
[17] Brit. Med. Journ., September 11, 1909, p. 645.
[18] Chassaignac, Plans de la Tête, 1842.
[19] Milligan, Trans. of the Otolog. Soc., vol. viii, p. 69.
[20] Boston City Hosp. Reports, 1894.
[21] Delfau and Günther narrate a case in which death occurred from pressure on the tenth nerve. (Deutsche Klinik, Berlin, 1853.)
[22] System of Surgery, vol. i, p. 93.
[23] Surgical Experiences in South Africa.
[24] Edin. Med. Journ., 1909, p. 526.
[25] Johns Hopkins Hospital Bulletin, April, 1909.
Extra-dural hæmorrhage may be arterial or venous in origin. In the former case the blood is derived almost exclusively from the middle meningeal artery. When of venous origin the source is usually to be found in a laceration of one of the sinuses of the brain. When blood is poured out from a torn sinus it tends to occupy, and be widely diffused in, the subdural space. A venous extra-dural extravasation is relatively of infrequent occurrence, and the pressure exercised on the brain seldom suffices to permit of the development of local or general symptoms of cerebral compression. On these grounds extra-dural hæmorrhage may be regarded as almost necessarily of arterial origin, and as derived from a torn middle meningeal artery.
The middle meningeal artery enters the middle fossa of the skull through the foramen spinosum, and divides, after a short intracranial course, into two main terminal divisions, anterior and posterior. The anterior branch passes forwards towards the anterior inferior angle of the parietal bone, then changing direction and turning upwards and backwards towards the vertex of the skull. The posterior branch passes horizontally backwards—grooving the squamous portion of the temporal bone—towards the posterior inferior angle of the parietal bone.
Throughout their intracranial course the main trunk and its terminal branches are embedded in the outer wall of the dura mater, except in the spheno-parietal region, where the anterior branch of the artery usually occupies a channel in the bone—one between 1⁄2 and 1 inch in extent.
The anterior branch overlies the pre-Rolandic motor area, whilst the posterior division is related to the temporo-sphenoidal and lower parietal regions—‘silent’ areas of the brain.
Middle meningeal hæmorrhage occurs most commonly in connexion with a fissured or comminuted fracture of the temporal region—the result of direct violence. A fracture, however, is not necessarily present, the hæmorrhage may take place on the side opposite to that at which the injury was received (laceration by contre-coup), and both vessels may be involved. Crisp English narrates three cases in which bilateral extravasation resulted. These more rare examples of middle meningeal hæmorrhage are more or less confined to patients suffering from marked arterial degeneration.
Middle meningeal hæmorrhage, uncomplicated by brain injury, is of infrequent occurrence, the associated injuries to bone and brain confusing the diagnosis. Moreover, the special pressure effects are dependent not only on the absence of serious brain lesion, but also on the non-existence of a safety-valve, such, for instance, as is afforded by a comminuted fracture of the bones entering into the formation of the temporal fossa, or of the roof of the middle and external ears. In the former case, blood will force its way into the temporal region, there forming a temporal hæmatoma—one that may pulsate—whilst, in the latter case, the blood escapes freely from the external auditory meatus. It should be noted, however, that pressure applied to the temporal hæmatoma may lead to the development of irritative or paralytic symptoms confined to the muscles of the opposite side of the body, whilst the restriction of aural bleeding, by means of plugs inserted into the ear, will lead to the early development of compression symptoms.
The amount of blood extravasated varies—according to the calibre of the vessel involved—from a drachm to several ounces. The largest coagulum that has come under my observation was 41⁄2 inches in the long diameter and 1 inch in thickness. Krönlein narrates a case in which the clot weighed 9 ounces.
Fig. 50a. The Inner Aspect of the Skull.
Fig. 50b. The Inner Aspect of the Skull seen on Transillumination.
In shape the clot is elliptical; in consistency it is either fluid or jelly-like. During the early stages of its formation it can be readily removed. Later on, it adheres to the dura mater, and, when removed, leaves that membrane rough and discoloured.
Some uncertainty exists as to the relative frequency with which the trunk and the two terminal branches are exposed to injury. There can be no doubt that the majority of cases in which typical clinical symptoms are present are such as evidence injury to the anterior terminal division; this is due to the anatomical relation of the clot to the motor cortex. Injury to the main trunk is of the rarest occurrence, for the foramen spinosum lies immediately anterior to the petro-sphenoidal suture, the course pursued by typical middle fossa fractures. I have seen one case only, and have read the accounts of two others, in which the foramen spinosum was directly implicated.
The attachment of the dura mater to the sides and base of the skull exercises a most important influence on the direction in which the blood spreads. Firmly adherent to the lesser wing of the sphenoid in front and to the summit of the petrous bone behind, the membrane intervening between these two regions is but loosely attached to, and readily stripped away from, the floor of the middle fossa. As the clot increases in size it exerts considerable mechanical pressure and tends to separate still further the dura from the bone. The anterior and posterior limitations compel the blood to extend first in the outward direction and then upwards towards the vertex of the skull.
Krönlein divides middle meningeal extravasations, according to their regional distribution, into three main groups:—
Temporo-parietal (the most common variety).
Parieto-occipital (rare).
Parieto-frontal (very rare).
Middle meningeal hæmorrhages yielding typical clinical symptoms are of infrequent occurrence, yet such extravasations are very commonly present in severe lesions of the skull. This is evidenced by the fact that middle meningeal hæmorrhage—of a greater or lesser degree—was found in 20 per cent. of all cases of fractured skull, and in 45 per cent. of those in which the middle fossa was involved. My experience is confirmed by Dwight and Nichols. For example, Dwight, in 149 autopsies, notes that middle meningeal hæmorrhage was existent in 49 cases (29 per cent.). He maintains further that the artery is injured in nearly every case in which the fracture, extending from vault to base or vice versa, involves the middle fossa of the skull. Nichols reports 11 cases in 32 autopsies (34 per cent.).
As the direct result of the blow the patient is ‘concussed’, remaining in that condition for a variable period of time, a matter of seconds, minutes, or hours, according to the nature of the associated damage to the bone and brain. In the most typical cases, the patient, on regaining consciousness, should recover—again for a variable period of time—complete control over mind and body, returning to work, walking home or visiting hospital or doctor. More usually, however, he remains slightly dazed, though recognizing his surroundings and capable of answering questions. In any case—unless the hæmorrhage is accompanied by grave cerebral lesion—there should be some attempt at recovery, some return to consciousness. The importance of this ‘lucid interval’ cannot be over-estimated. It should be noted, however, that this interval of consciousness is not of itself absolutely diagnostic of middle meningeal hæmorrhage—it ought to be associated with definite localizing symptoms of brain compression (see below). I have encountered several cases in which this lucid interval was present, and in which operative procedures were carried out in the anticipation of finding an extra-dural extravasation, only to find a subdural hæmorrhage. Such subdural hæmorrhages are not infrequently associated with a similar return to the conscious state, but are rarely—if ever—accompanied by the early development of symptoms of localized brain compression. In the event of doubt as to whether the surgeon has to deal with an extra or subdural extravasation lumbar puncture will probably clear up the diagnosis.
The duration of this ‘lucid’ interval is exceedingly variable. It is usually a matter of minutes or hours, though both König and Wiesman narrate cases in which eight days elapsed before the onset of definite localized compression symptoms. I also have recollections of a case in which the patient walked some miles across the moor to see his doctor, and finding him away from home, walked home again, then becoming unconscious and dying shortly afterwards.
All depends on the calibre of the vessel injured and on the existence of a safety-valve, by means of which some of the extravasated blood can escape externally (see p. 97).
No rule can be laid down as to the duration of this ‘lucid’ interval, but all authorities are agreed as to its existence, even though it may be of exceeding short duration. Its importance, from a clinical point of view, cannot be overestimated. It was present in 43 out of 63 cases reported by Jacobson, well marked in 32 (50 per cent.), less marked in 11 (18 per cent.). It was observed in 60 per cent. of cases that came under my care.
During this period the blood is occupied in stripping away the dura from the bone—the larger the vessel the easier the task and the shorter the ‘lucid’ interval.
The further progress of the case may be considered according to the general and local effects of the hæmorrhage.
As soon as the clot becomes of sufficient size as to exert general pressure on the brain, symptoms of compression become evident, the patient first entering on the stage of ‘slow cerebration’. He is dull and apathetic, showing marked delay in responding to questions. As the pressure increases, he gradually passes into a state of unconsciousness.
The pulse becomes full and slow, the blood-pressure rises progressively (to 200 or more mms. of Hg.), respiration is laboured and stertorous, and the temperature raised (rising progressively). The skin is hot, the face turgid and cyanosed. If the pressure is unrelieved, stimulation of the medullary centres gives place to exhaustion, the pulse becoming irregular and rapid, blood-pressure falls rapidly, and respiration is of irregular rhythm and finally Cheyne-Stokes in character. Finally, the patient becomes completely comatose, the pupils are widely dilated, and the cornea insensitive. Both urine and fæces may be passed (through paralysis of the sphincters), the extremities exhibit flaccid paralysis and the reflexes are abolished. Death occurs primarily through paralysis of the respiratory centre.
In many cases considerable help to diagnosis may be obtained by external examination—bruising and ecchymosis, or definite hæmatomata, in the temporal or parietal regions. In some cases the hæmatoma may pulsate, and in others the application of pressure to the hæmatoma will lead to the development of fits involving the face and extremities on the contra-lateral side. Copious hæmorrhage from the ear should always arouse suspicion as to the probability of an extra-dural hæmorrhage (see p. 97).
The anterior branch of the artery, as it passes upwards towards the vertex, overlies the pre-Rolandic or motor area. The pressure exercised on that region of the brain leads—according to the site of extravasation and the degree of pressure exercised—to the development of twitchings, convulsions, spasticity, or paralysis of the muscles of the face, upper and lower extremities on the contra-lateral side of the body.
Fig. 51. To illustrate Compression of the Brain. As produced by an extra-dural hæmorrhage from the posterior branch of the middle meningeal artery.
The late Professor von Bergmann[26] pointed out that the arm area is most commonly affected, and that the leg area is never alone implicated. Wiesmann[27] states ‘that isolated paralysis of the leg area is never seen, but only paresis when the arm is paralysed, or both may be similarly affected at once; convulsions may precede the affection’.
In discussing the frequency of local compression effects, Wiesmann points out that some abnormal condition of the opposite extremities was only absent in 16 out of a total of 257 cases. In 37 cases reported by Jacobson,[28] hemiplegia, of a greater or lesser extent, was present in 19 (50 per cent.). The same authority explains that ‘with regard to the onset of convulsions, if there be restlessness, spasmodic twitchings, or movements of the limbs, it is only too probable that in addition to middle meningeal hæmorrhage, contusion or laceration of the brain-substance will be found at more places than one’.
In cases that have come under my observation twitchings of the muscles of the face and upper extremities were observed in 37 per cent. of cases, and paralysis in the same number. Some alteration in the condition of the muscles on the contra-lateral side was present therefore in 74 per cent. of cases.
If the hæmorrhage be situated on the left side of the brain, both motor and sensory cortical speech areas may be involved, especially the former.
With respect to reflexes, it has previously been stated that the reflexes are abolished. This is true with respect to the later stages of fully-developed compression. In the earlier state the reflexes on the contra-lateral side may be increased, the difference between the two sides affording some help in the differential diagnosis.
are variable. According to Jonathan Hutchinson, the pupil on the affected side becomes dilated, the blood extending inwards towards the cavernous sinus and exercising direct compression of the third nerve. The frequency with which a dilated pupil occurs in cases of middle meningeal hæmorrhage, and the causation thereof, are, however, matters of dispute. Phelps writes as follows: ‘Reference to cases cited show that the so-called Hutchinson pupil may be observed as well in hæmorrhages occurring in other situations than the middle fossa, and in some cases of cerebral lesion without injury at all. There is no reason to doubt that it is the result of cerebral contusion, but in what relation they stand to specific cerebral injuries is undetermined.’
Walton states that ‘doubtless various factors play an important part in producing the dilated pupil, but if disorders of any simple mechanism are to be credited with the production of the Hutchinson pupil or other pupillary changes, the only lesion worthy of the place is disturbance, irritative or paralytic, of the intracranial fibres of the cilio-spinal tract’.
The late Professor von Bergmann, from 70 cases, reports as follows:—
In 39 cases both pupils were markedly dilated (56 per cent.).
In 7 cases both pupils were markedly contracted (10 per cent.).
In 20 cases the pupil on the same side was dilated (30 per cent.).
In 4 cases the pupil on the opposite side was dilated (6 per cent.).
Parsons, in answering some queries in 1903, writes:—
‘I should anticipate from cortical irritation bilateral pupillary dilatation, perhaps more marked on the opposite side: from pressure the opposite effects, so far as mere cortical paralysis goes, but this would be more liable to be vitiated by vascular changes—the complex condition seen in coma. It is very difficult to elicit pupillary constriction by cortical stimuli—very easy to elicit dilatation, but always bilateral though often more marked on the opposite side.’
In cases examined by me the following conditions were found:—
| Pupils equal | 46 | per cent. of cases |
| Pupils constricted on the affected side | 36 | per cent. of cases |
| Pupils dilated on the affected side | 18 | per cent. of cases |
From my experience, therefore, and from that of the authorities quoted above, it would appear that alterations in the size of the pupil are of very doubtful significance in the diagnosis of middle meningeal hæmorrhage, and that the ‘Hutchinson pupil’ is but rarely observed.
The results obtained by ophthalmoscopic examination are of much greater value. Such investigations should be carried out as a routine procedure. In the earlier stages of the hæmorrhage some œdema of the disk, together with dilatation of retinal veins and diminution in the calibre of the arteries, will be observed on the affected side. This affords a most valuable aid in the differential diagnosis as to the side on which the hæmorrhage is situated—not always such a simple matter as appears at first sight.
Operation is indicated in all cases of middle meningeal hæmorrhage if the condition of the patient be compatible with such treatment. The earlier the operation is carried out the better.
After the usual preparatory treatment, the ‘site of election’ for trephining is marked out on the scalp by taking a point which lies 2 inches posterior to the external angular frontal process, and the same distance above the zygoma. A bradawl may be introduced so as to indent the external table of the skull, thus aiding the subsequent accurate application of the trephine.
Fig. 52a. Exposure of the Branches of the Middle Meningeal Artery. First stage. Suitable scalp-flaps have been turned down, and the skull has been trephined over the ‘sites of election’ for exposure of both anterior and posterior branches.
Fig. 52b. Exposure of the Branches of the Middle Meningeal Artery. Second stage. The trephine-holes have been enlarged with the craniectomy forceps in the required directions.
The incision commences immediately posterior to the external angular frontal process, curves upwards and backwards along the temporal crest, and terminates in front of the tragus of the ear. The flap, comprising skin, temporal fascia and muscle, and pericranium, is turned to its zygomatic base and all bleeding-points secured.
The subsequent procedures vary according to the condition of the bone:—
If there be no fracture of the bone, the pin of the trephine is applied to the indented spot and the disk of bone removed. After the removal of the disk the clot will be exposed; but, in order to obtain full exposure, the gap must be enlarged with the craniectomy forceps, mainly in the upward and downward directions.
If a fissured fracture be found, the trephine is applied in close relation to the intersection of the line of the artery and the line of the fracture, the gap being enlarged in the required direction.
When the fracture is comminuted, the fragments of bone are either elevated or removed until sufficient room has been obtained.
The greater part of the clot can be removed with a Volkmann spoon, or with an ordinary teaspoon, and the region flushed out with hot saline solution.
When the artery is injured beyond the limits of the gap, the bone must be nibbled away till the bleeding-point is exposed. In some cases it may be necessary to remove a considerable portion of the bone entering into the formation of the temporal fossa. In the meantime, hæmorrhage may be controlled by plugging towards the base of the skull with strips of gauze. Sufficient room having been obtained, the gauze is withdrawn, when smart sponging should enable the operator to determine the source of the hæmorrhage. At this stage of the operation, a head-lamp is useful. After the exposure of the bleeding-points, the following measures can be adopted whereby to arrest the bleeding:—
(a) The application of a ligature or of silver ‘clips’ (see Fig. 6) on either side of the bleeding-point.
(b) The vessel may be underrun on either side of the bleeding-point.
(c) The vessel may be seized with artery forceps and twisted.
(d) The hæmorrhage may be arrested by means of gauze plugs.
(e) The foramen spinosum may be occluded with bone or wooden pegs.
(f) The common or external carotid arteries may be ligatured.
Every effort should be made to control the hæmorrhage by means of ligature, silver clip, underrunning, or torsion. Gauze plugs may usually be relied on to stop the bleeding, but they possess the great disadvantage of exercising pressure on the cortex and preventing expansion of the brain.
Occlusion of the foramen spinosum and ligature of the carotid arteries complicate and prolong the operation. The foramen spinosum is occluded in the following manner: the dura mater is quickly stripped up with the fingers away from the base of the skull, the soft parts gently but firmly retracted and the foramen identified. Its occlusion may be effected by means of a sterilized wooden match or bone peg, by a small piece of bone derived from those osseous fragments which have been removed during the operation, or with the aid of a piece of catgut; in each case the occluding medium should be well driven into the foramen.
It is open to doubt whether ligature of the carotid arteries is ever necessary, though several cases have been recorded in which such a procedure was carried out. The external carotid should be tied in preference to the common vessel, further interference with the blood-supply of the brain increasing necessarily the risk of cerebral œdema, &c.
The hæmorrhage having been arrested by one or other of these methods, the cavity is thoroughly washed out with hot saline solution and drained, a small rubber drainage-tube being brought out through the scalp-flap. The tube should be removed after twenty-four to thirty-six hours, according to the circumstances of the case.
The ‘site of election’ for exposure of the posterior branch lies at the intersection of the two following lines:—
A line drawn backwards from the upper border of the orbit parallel to Reid’s base-line.
A line drawn vertically upwards from the posterior border of the mastoid process.
The trephine is applied, the disk removed, and the gap enlarged with the craniectomy forceps in the forward and backward directions. The hæmatoma is evacuated and the bleeding arrested after the methods enumerated above.
The ultimate result of operation for middle meningeal hæmorrhage depends on two factors—the time at which operation is carried out, and the question of brain lesion. There is every reason to believe that, when treated early and when uncomplicated by brain injury, the prognosis, both immediate and remote, is wholly satisfactory.
Wiesman[29] collected 257 cases, of which 110 were submitted to operation, with a mortality of 27 per cent. Of the cases in which no operation was performed 88 per cent. died.
Duchaine[30] reports 27 cases in which operation was carried out, with death in 6 cases only, a mortality of 22 per cent.
Von Bergmann collected 110 cases treated by operation, with 74 recoveries and 36 deaths, a mortality of 32·27 per cent.
Blake only lost 3 cases out of a total of 42 submitted to operation.
Even when every allowance is made for the fact that operative measures were adopted in the more hopeful cases, the above statistics show conclusively that early operation affords great hope of cure.
Fig. 53. A Basic Fracture with Laceration of both Carotid Arteries.
Before passing on to subdural hæmorrhage, it will be convenient to discuss briefly the question of injury to the internal carotid artery.
This vessel, during its forward passage in the outer wall of the cavernous sinus, from the posterior to the anterior clinoid processes, crosses the line of the typical middle fossa fracture (see p. 84). The artery is loosely embedded in the sinus, it is protected by the third, fourth, ophthalmic division of the fifth and sixth nerves, and it is situated some distance above the level of the base of the skull. In spite of this degree of protection from injury, the artery may be lacerated in this part of its intracranial passage. The basic fracture is necessarily of a very severe nature. Two cases have come under my own care: one in which both arteries were torn across, the fracture passing from one middle fossa to the other, with such wide separation of the anterior and posterior segments of the skull that the two were freely movable on one another (Fig. 53), whilst in the second case, the fracture, originating in the left frontal region, passed backwards across the anterior fossa, comminuting the base in the region of the cavernous sinus, lacerating that sinus and tearing the artery (Fig. 54).
Fig. 54. A Basic Fracture with Laceration of the Cavernous Sinus. A, The optic nerve; B, The cavernous sinus; C, The third nerve; D, The internal carotid artery.
In both cases death was almost instantaneous, blood pouring from the nose and mouth.
In some few cases the vascular lesion is confined to a minute tear in the coats of the vessel, a fistulous communication being formed between the artery and the cavernous sinus—arterio-venous aneurysm. This condition is discussed on p. 204.
Hæmorrhage into the subdural space may be (a) diffuse, or (b) localized.
The blood may be derived from one of the great sinuses of the brain or from superficial cerebral vessels (laceration of the brain).
The superior longitudinal sinus may be torn by the in-driving of fragments of bone in a comminuted depressed fracture of the vertex, or by wide separation along the line of the sagittal suture. Blood is diffused throughout the subdural space, on one or on both sides of the falx cerebri, but always tending to gravitate towards the lower limits of the supra-tentorial space.
In the event of the wound being compound, air may enter into the sinus. Insomuch, however, as the sinus pressure is, under normal conditions, positive, this complication is of rare occurrence, unless the patient is in a state of profound shock, from loss of blood, or suffers from urgent dyspnœa.
Allusion should also be made to the condition described by Stromeyer, as ‘sinus pericranii’, where a subpericranial hæmatoma communicates with a venous sinus. Such hæmatomata may pulsate, are more or less reducible on pressure, and are increased on straining or on the application of pressure to the internal jugular vein.
The lateral sinus may be laid open in any part of its course, more especially at the angle of junction between the lateral and sigmoid sinuses, in close relation to the occipito-mastoid suture, a region not infrequently involved in basic fractures. The blood effused will occupy the supra- or infra-tentorial spaces according to the situation of the rent in the sinus-wall.
The cavernous sinus is frequently involved in anterior and middle fossa fractures. The blood effused usually escapes into the nose and mouth.