HERNIA CEREBRI

The term Hernia cerebri was formerly used as inclusive of all those conditions in which the brain protruded through some aperture in the skull, whether such opening was congenital, traumatic, or post-operative.

Owing to the recent advances in cranio-cerebral surgery, especially with reference to the frequent adoption of decompression operations, it is advisable that the cases should be classified into two groups:—

1. Cases of hernial protrusion, including cephaloceles (see [Chapter I]), protrusions intentionally produced by the surgeon in a decompression operation, and those which follow after unsuccessful operations for tumour removal. It will be observed that, in all these cases, the projecting brain, though bulging through its osseous barrier, is still protected by a more or less normal scalp-covering.

2. Cases of hernia cerebri. Here, as the result of injury to scalp, bone, dura, and brain, the cerebral substance bulges through a deficiency in the vault and presents on the surface, uncovered by integument. Hernia cerebri can develop under non-infective conditions, the congested state of the bruised or lacerated brain bringing about that degree of intracranial tension which can only be relieved by the outward projection of the brain. Still it must be accepted that Hernia cerebri almost invariably implies some bacterial infection.

Hernial protrusions are dealt with elsewhere. Hernia cerebri requires some consideration. Its development, by reason of its usual bacterial agency, must always be regarded as of serious import. The congested brain bulges through the aperture in the skull and presents on the surface as a purple—sometimes black—fungating mass, bleeding freely, and associated with a considerable discharge of cerebro-spinal fluid, serum, and pus.

The effects produced by this condition vary according to the extent of the cerebritis, and the question of associated meningeal infection.

When associated with meningitis those symptoms which might result from the hernial protrusion are more or less obscured by those dependent on the meningeal infection. Under other circumstances, the symptoms vary according to the extent and position of the area involved. Thus, when the infection is limited to the surface of the brain in the immediate vicinity of the aperture in the bone, the patient may merely complain of some headache and present some symptoms of cerebral irritation. More usually, the infection spreads rapidly to the surrounding brain substance, and the patient evidences the most acute stage of cerebral irritation, passing thence rapidly into a stuporose, typhoid-like condition.

A

Fig. 86. A Case of Hernia cerebri. A, The abscess after removal (natural size), cut so as to show the thickness of capsule.

Treatment.

With the object of reducing the infectivity of the protruding brain, fomentations have been advocated. From my own experience, however, it would appear that their application tends to increase the degree of protrusion, and that better results may be obtained by keeping the exposed brain as dry as possible, painting over with a 21⁄2 per cent. solution of iodine in rectified spirit, dusting with antiseptic powder, and protecting with dry dressings, frequently replaced.

In the event of failure to improve the condition by means of these minor remedies—a too-frequent occurrence—excision of the protruding mass may be regarded as a perfectly justifiable procedure, providing that the hernia does not include the cerebellum or motor cortical region. The protrusion is shaved away flush with the level of the skull, the raw surface of the brain lightly painted with iodine, dusted with iodoform or other antiseptic powder, and protected with gauze and wool.

The prognosis is necessarily most grave, but the most astounding recoveries have taken place under this mode of treatment.

[52] Archiv für Ohrenheilkunde, vol. xxix, p. 17.

[53] Diseases of the Ear, Oxford Medical Publications, p. 257.

[54] Pyogenic Diseases of the Brain and Spinal Cord.

[55] Some Points in the Surgery of the Brain, p. 95.

[56] Macewen, Pyogenic Diseases of the Brain and Spinal Cord.

[57] Pyogenic Diseases of the Brain and Spinal Cord, p. 247.

[58] Pyogenic Diseases of the Brain and Spinal Cord.

CHAPTER IX
BULLET-WOUNDS OF THE SKULL AND BRAIN

In the consideration of bullet-wounds of the skull and brain the following factors must be taken into account:—

The velocity of the bullet.

The distance at which the bullet is fired.

The size of the bullet.

The nature of the bullet.

The angle of impact.

The position of the bullet at the moment of impact.

Before, however, noting the varying effects on the skull as produced by one or more of these factors, it will be necessary to allude briefly to the average effect on the skull as produced by bullet-wounds in general.

‘When a foreign body passes through any part of the skull—it matters not what the direction may be—the aperture of exit is always greater than the aperture of entry.’ Such was the law enunciated by Teevan in 1864. The explanation is as follows: ‘The aperture of entry is caused by the penetrating body only, whilst the aperture of exit is larger, insomuch as it is made by the penetrating body plus the fragments of bone driven out of the proximal table and diploe.’ It might also be added that the greater degree of damage will always be incurred by the unsupported table—the internal at the wound of entry, the external at that of exit.

The size and shape of the aperture of entry through the external table bears a close resemblance to the size and shape of the entering bullet. As a general rule, it is round or oval, and presents clean-cut edges with some small radiating fissures. The aperture of entry through the internal table is larger, the margins inverted towards the brain, the radiating fissures more pronounced, and small fragments of bone in-driven towards the brain.

In the event of perforation of the skull through the medium of a high-velocity bullet, the aperture of exit through the internal table closely resembles that through the external table at the site of entry, with the exception that it is influenced by any changes in position that the bullet may have undergone during its transmission through the brain. The wound of exit through the external table is again greater than that through the internal—in accordance with Teevan’s law—the margins everted, the surrounding bone fissured or comminuted, whilst fragments of bone may be driven out beneath the lacerated scalp, or even blown completely away. On the other hand, when the bullet is fired at close range, the aperture of exit is often considerably larger than that of entry—due, in all probability, to superadded explosive effect.

The effect of the velocity of the bullet on the fracture:—The greater the velocity of the bullet the greater the resemblance of the wounds of entry and exit to the size and shape of the bullet, the ‘cleaner’ the holes, and vice versa.

The effect of distance:—When the bullet is fired from a distance, but with full effect, the hole is clean cut and presents the characteristics enumerated above. When the bullet is ‘spent’, the osseous injury at the point of impact is usually of a more extensive character than when the bullet possesses a higher degree of velocity. When fired at close quarters the damage incurred from the impact of the bullet is increased by the force of the forwardly driven air and gas. The skull suffers proportionately, the scalp being severely lacerated, burnt, and circumferentially ingrained with powder, the bone extensively comminuted, and the brain severely lacerated.

The effect of size and shape of the bullet:—The effects produced on the skull in relation to the size and shapes of the bullet are so obvious as to require no description. The nature of the bullet must also be taken into consideration, whether of the soft-nosed variety, expansile, &c.

The effect of the angle of impact:—The lesion produced by the bullet varies according as to whether the bullet glances across the vault or strikes the bone at right angles. In the former case a ‘gutter’ fracture may result, varying in degree and associated brain complication according to the angle of impact. In the latter case the skull is penetrated or perforated.

The effect of the position of the bullet at the moment of impact:—The bullet, at the moment of impact, may be so changed in position—head-over-heels, ricochet, &c.—that the skull may be struck by its long axis instead of by its nose. In such cases, the wound of entry will be more extensive than under ordinary circumstances.

It is obvious, therefore, that many factors require consideration in estimating the extent of the osseous lesion and the nature of the complications existent in any given case. Due allowance must also be paid to other factors entering into the case, more especially in relation to the weapon used—pistol, revolver, gun, &c.

Injury to the bone.

The various injuries to bone may be classified as follows:—

Fractures limited to the external table.

Fractures limited to the internal table.

Gutter fractures.

The complete fractures produced by a penetrating wound.

The complete fractures produced by a perforating wound.

Fractures limited to the external table.

Fractures of this nature are of exceedingly rare occurrence. They are produced by a bullet which strikes the skull in such an oblique direction that the scalp and external table are torn away (‘gutter’ fractures), or by a bullet which, directed against the outer wall of the frontal sinus, possesses sufficient force to comminute the outer wall of that sinus, but, from loss of momentum, is incapable of penetrating further.

Fractures limited to the internal table.

These fractures are even more rare than those described above. Their occurrence is probably only possible when the bullet strikes the skull in a markedly oblique direction, and with greatly diminished velocity—‘spent’ bullets. I believe I am correct in stating that only one instance of this particular variety of fracture was observed in the South African War. In any case, they are of such infrequent occurrence that they may be practically disregarded.

Gutter fractures.

Gutter fractures are almost invariably dependent on the impact of a glancing bullet. They may be arranged in three groups, according to the extent of the osseous lesion.

1. Where the external table is blown away, leaving the internal table exposed, perhaps comminuted.

2. Where the internal table is driven in the inward direction, pressing on, irritating, and perhaps lacerating the dura mater.

3. Where the whole thickness of the bone is blown away, leaving a gaping wound from which brain-matter may protrude.

Fig. 87. Diagrammatic Illustration of the Three Forms of ‘Gutter’ Fracture. (For further description, see text.)

The complete fractures produced by penetrating and perforating wounds.

The general effects as produced by penetrating and perforating bullet-wounds of the skull and brain are depicted in [Fig. 88], and described in the text associated with that figure.

Injury to the brain.

Brain lesions vary ‘from a single track with small points of extravasation in neighbouring areas to a condition of hæmorrhagic pulp, which latter condition is the result of injury from the projectile associated with bleeding, often extensive, into neighbouring areas, disintegrating and pulping the brain-substance. These latter cases are generally fatal, and are accompanied not infrequently with meningeal and ventricular hæmorrhage’ (Bowlby).[59]

The worst degrees of brain-injury arise when the injury is inflicted at close range, more especially at the site of emergence of a perforating bullet, the damage to the soft parts being there magnified by the waves and vibrations set up by the bullet during its passage across the brain. In many cases also the brain is dashed as a whole against the opposing osseous barrier (laceration by contre-coup).

The general effects produced on the skull and brain by a perforating bullet of high velocity are shown in [Fig. 88].

Symptomatology.

It is unnecessary to enter into details with regard to the symptoms arising from bullet-wounds of the skull and brain, for they closely resemble those previously enumerated in the chapters dealing with fractures of the skull and injury to the brain. There are, however, a few special points to which attention should be directed.

1. External hæmorrhages are seldom profuse.

2. The escape of cerebro-spinal fluid is of infrequent occurrence, probably due to the fact that the apertures of entry and exit are blocked up with scalp, fragments of bone, and pulped and swollen brain.

3. Concussion and irritation are prominent symptoms, compression is rarely seen in its typical form. As Spencer[60] says, ‘The dominant feature is usually concussion. The extent of the paralysis depends on the region injured, and there is often at first extensive temporary paralysis from vibratory concussion of the brain substance suspending its functions over a wide area around the bullet-track.’ Cerebral irritation and Jacksonian fits are frequently observed.

Indications for operation.

There is a great uniformity of opinion with regard to the indications for operation as expressed by those who have had considerable experience in wounds of this nature. One has only to glance through the works of recognized authorities—Spencer,[61] Bowlby,[62] Makins,[63] Lawford Knaggs,[64] &c.—to see that it is an accepted rule that all bullet-wounds of the skull and brain call for early operative interference, it being granted that the condition of the patient is compatible with such treatment.

Operation.

The operative details may be considered under two headings:—

(a) The exploration of the wounds of entry and exit.

(b) The search for and removal of the bullet.

Fig. 88. To illustrate the Effects produced by a Perforating Bullet-wound. 1, The inverted scalp at wound of entry; 2, Subaponeurotic hæmorrhage; 3, The wound of entry into the skull; 4, Extra-dural hæmorrhage; 5, Lacerated dura mater; 6, Subdural hæmorrhage; 7, In-driven fragments of bone; 8, The passage through the brain-substance; 9, Ventricular hæmorrhage; 10, The wound of exit through the brain; 11, Subdural hæmorrhage; 12, The wound of exit through the dura mater; 13, The wound of exit through the skull; 14, The wound of exit through the scalp.

[Larger illustration]

The exploration of the wounds of entry and exit.

Whether the skull be penetrated or perforated, the wounds are investigated after similar general principles. After careful shaving and cleansing of the whole scalp, and after application of the scalp-tourniquet, a scalp-flap is turned down, the centre corresponding as far as possible to the site of entrance or emergence of the bullet. The under aspect of the flap is examined for loose fragments of bone, hair, portions of headgear, &c. These are removed and the flap cleansed. The bone is next examined. All loose fragments are removed, both large and small. The smaller are discarded, the larger are boiled (for ten minutes) and preserved in hot saline solution for replacement at the termination of the operation, if such a course should be deemed advisable (see [p. 132]). Those fragments of bone which retain their pericranial attachments are merely elevated and turned aside, to be again placed in position at the proper time.

Trephining is seldom necessary, the hole in the bone usually allowing of the application of craniectomy forceps, if any enlargement should be requisite.

A good view of the dura mater can now be obtained. If that membrane be merely punctured or incised, the tear must be enlarged with blunt-pointed scissors so as to allow of complete examination of the underlying brain. Hæmorrhage from meningeal vessels is controlled by the application of ligatures to all vessels that cross the line of dural section.

The lacerated brain is gently irrigated with saline solution (at a temperature between 110° and 115° Fahrenheit), and all blood and pulped brain matter washed away. The cortex is then lightly examined with the finger and probe for any fragments of bone that may be embedded in the brain substance. The removal of such fragments should be conducted with all possible gentleness. The surgeon should be satisfied that no foreign body remains. The bullet, when encountered, is removed. Needless to say, the presence of a bullet and the existence of in-driven fragments of bone should be investigated previous to the adoption of operative measures by means of X-ray photography.

If the brain be penetrated or perforated a drainage tube is introduced through scalp-flap and dura mater in such a manner that its distal end lies in relation to the track through the brain or flush with its lacerated surface. Elsewhere the dura is sewn up (fine catgut sutures) and the scalp-flap replaced, the drainage tube being anchored to the scalp with a single suture. The tube should be allowed to remain in situ for at least forty-eight hours and longer if necessary, the surgeon being guided by the amount of discharge and by the general progress of the case. In all cases of doubt the surgeon should err on the side of leaving the tube in position for a longer period of time, merely shortening it daily. Premature removal may lead to disastrous results. There can be no question that ultimate success hinges to a large extent on primary or early healing of the wound.

The search for and removal of the bullet.

In the event of a wound of entry only, it may be presumed that the bullet is within the skull. Bullets, however, pursue such unexpected and devious courses within the skull, and possess such a tendency to gravitate towards the base of the brain, that no attempt should be made at removal except after full X-ray investigation, stereoscopic if possible.

To this rule there are two exceptions:—(1) where the bullet lies superficial in the brain substance, and (2) where there exists, at the opposite side of the skull, what may be termed an area of attempted exit, that is to say, an area of bone elevation and blood extravasation, suggesting that the bullet has penetrated through the brain and impinged against the opposite side of the skull. In both these instances operative measures are not only justifiable but often definitely indicated. On the other hand, it cannot be urged too forcibly that hasty and ill-determined explorations usually terminate in failure. Even under the most promising circumstances it by no means follows that the bullet will be found at the site of counter-trephining, as it may have rebounded to some more distant region of the brain, necessitating an operation conducted over a totally different region. Thus, in a case recently under my care, the bullet entered at the right temporal region, penetrated the brain and produced on the left side of the head a well-defined wound of attempted exit. The bullet, however, on striking the opposing side of the skull rebounded, and was subsequently found in the apex of the descending cornu of the right lateral ventricle. This case affords a good example of the uncertain course pursued by bullets entering the cranial cavity.

However, in certain cases of emergency and in others of expediency an immediate search should be made for the bullet. The operation should be carried out with a light hand and not unduly prolonged.

In order to find and remove the bullet various probes and extractors have been invented. Perhaps the best of these is Sheen’s bullet-forceps, probe, and telephone-detector.

‘The forceps are so constructed that they may be attached directly to the telephone-detector and used as a combined probe and forceps, or they may be used in combination with the specially designed graduated probe attached to the detector in the following manner: The bullet having been located with the probe, the forceps are introduced along the probe, the jaws of the forceps being provided with an oblique groove for this purpose. In both methods of use the telephone-detector is in uninterrupted contact with the bullet during extraction, an advantage which much facilitates the operation, and ensures the least possible damage of tissue. In cases where the forceps are used as a probe and forceps combined, the connexion attached to the forceps is composed of silver wire, which can be readily sterilized, and while of sufficient rigidity to avoid risk of accidental short-circuiting with the patient’s body, is flexible enough not to interfere with the delicacy of manipulation. The telephone-detector is placed on the head of the operator, and the flat plate on the patient’s body, good contact being secured by means of a damp roll of lint, or other material, moistened with a saturated saline solution.’

Fig. 89A. Sheen’s Bullet-probe and Forceps.

Fig. 89B. Sheen’s Telephone Bullet-detector.

‘The probe is introduced, and when a metallic foreign body is touched a fall of potential occurs, and the telephone buzzes. It is necessary to point out that no mistakes can be made, as may be the case with a battery in circuit. In using the “auto-telephone probe” the body constitutes an electrolyte, the plate one pole of a voltaic circle, the probe the other; on touching a metallic body different to that of the probe, a difference of potential occurs, and the current ensuing flows through the telephone and is recorded by the diaphragm in the usual way.’[65]

If the bullet be not found it should be allowed to remain in situ till such time shall have elapsed as will enable the surgeon to determine whether further operative measures are indicated, time being allowed also for skiagraphy and for the evolvement of another plan of campaign. It is of course a well-known fact that bullets in certain regions of the brain—e. g. the frontal lobe—may exercise but little effect on the individual. Further measures are also indicated when the want of cleanliness of the wound and the anatomical situation of the bullet demand secondary operative procedures. All remote operations are planned according to the localizing symptoms, aided by X-ray photography.

After exploration for and removal of the bullet an extensive osseous defect may remain. Opinions differ with respect to the time at which an attempt should be made to remedy the deficiency and as to the operative technique appropriate to the condition. The nature of the wound must always be taken into consideration, for the application of any plate of foreign material is doomed to failure in the event of the slightest degree of suppuration. As a general rule, it may be accepted that it is advisable to postpone such measures till after the primary or early healing of the wound. Further delay, however, tends to allow of the formation of such adhesions as will result in the development of Jacksonian epilepsy, chronic headache, traumatic insanity, &c. The operative features requisite to the interposition of plates between the bone and the scalp, and other measures, are fully detailed in [Chapter VI].

‘The after treatment consists in keeping the patient as quiet as possible, and the administration of a fluid diet. In some cases, recurring symptoms pointed to the continued presence of bone fragments; these were usually indicated by signs of irritation, or often by local inflammation, in the latter case infection taking the greatest share in the causation. Such cases needed secondary exploration, and the wonderful success of this operation, even when the wound was evidently infected, was perhaps one of the most striking experiences of surgery in general.’ (Makins.)[66]

Complications.

The more important early complications are meningitis, hernia cerebri, and brain abscess. For the Symptomatology and Treatment of these conditions the reader is referred to [Chapter VIII].

Results.

The prognosis in any given case depends on the degree of bone and brain injury, on the presence or absence of the bullet in the brain, and on the ‘cleanliness’ of the wound. In the American Civil War 61·2 per cent. of all fractures of the skull terminated fatally, in the Franco-German War 51·3 per cent., and in the South African War 33·1 per cent. This decreasing mortality is undoubtedly dependent on the improved methods of treatment.

When the injury is inflicted at short range the prognosis is undoubtedly less favourable. ‘At short range, the characters of the wounds, and the severity of the symptoms, rendered the immediate prognosis uniformly bad, a very great majority of the patients dying, and that at the end of a few hours or days.’ (Makins.)

The best results were obtained when the injury was received in the frontal region. The occipital region comes second, and the cerebellar last. Most injuries near the base of the skull were fatal. Longitudinal wounds were more serious than transverse. However, the most surprising recoveries were made, both with and without operative treatment.

The prognosis with regard to pistol wounds is absolutely bad. Phelps[67] records the following results in cases that came under his own observation.

Death occurred at once or within the first hour in 15 cases.

Death occurred within twelve hours in 7 cases.

Death occurred within fifteen hours to forty days in 10 cases.

Recovery in but 8 cases.

The more remote results are exceedingly difficult to determine, for it is impossible to obtain an accurate account of the subsequent course of events in all cases. With regard to the question of the after-history, Makins[68] writes, ‘I feel certain that a long roll of secondary troubles from the contraction of the cicatricial tissue, irritation from distant remaining bone fragments, as well as mental troubles from actual brain destruction, await record in the near future.’ In the experience of the writer, this statement is fully justified. The hospital surgeon continually meets with cases exemplifying the more remote effects, varying from slight lesions associated with chronic headache to others showing considerable deficiency in the vault of the skull with cortical degeneration.

Some of these cases are still capable of being cured, others are hopelessly inoperable.

In the consideration of the more remote results, it must be remembered that the surgeon comes mainly into communication with those cases which require further treatment. The more favourable are lost to view. Hence the difficulty in estimating with certainty the absolute results obtained after lesions of this nature.

[59] A Civilian War Hospital.

[60] Gunshot Wounds, p. 170.

[61] Gunshot Wounds.

[62] A Civilian War Hospital, p. 228.

[63] Surgical Experiences in South Africa, p. 293.

[64] Lancet, March 3, 1906.

[65] Army Med. Corps Journal, April 1905.

[66] Surgical Experiences in South Africa.

[67] Traumatic Injuries of the Brain, p. 387.

[68] Surgical Experiences in South Africa.

CHAPTER X
TRIGEMINAL NEURALGIA

Neuralgia of the fifth or trigeminal nerve is, in its varying degrees, of frequent occurrence. In its cause, manifestations, and progress, it offers so wide a field for discussion that the question must be focussed down by means of some simple form of classification such as enables one to include the majority of cases that come before one’s observation.

For all practical purposes, the following types will be sufficiently inclusive:—

Neuralgia minor.

Neuralgia major.

Hysterical neuralgia.