Louis Bathe Rawling

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.

NEURALGIA MINOR

This variety is almost invariably dependent in its development on some exciting cause. In some cases this cause is readily demonstrated, in others great difficulty may be experienced before the source is discovered.

These secondary neuralgias may be regarded as resulting from the following injuries and diseases.

Diseases of the tongue, fauces, and pharynx. For example, the pain referred to the lingual nerve in epithelioma of the tongue.

Diseases and injuries of the maxillÆ. For example, the neuralgia associated with dental caries.

Injuries and diseases of the nose and its accessory cavities. For example, the infra-orbital pain experienced in empyema of the antrum.

Injuries and diseases of the bones of the skull. For example, the pain referred along the course of those nerves emerging through the basal foramina involved in a fracture of the base of the skull.

Errors of refraction. For example, neuralgia of the supra-orbital nerve.

AnÆmia, influenza, alcoholism, Bright’s disease, cold, worry, malaria (brow-ague), rheumatism, &c.

But slight allusion need be made to the symptomatology of neuralgia minor—the conditions are more or less familiar to every one. The pain, though usually most intense in that particular branch of the nerve which is most intimately related to the source of the neuralgia, is often referred to other branches of the same nerve-trunk, and sometimes to an entirely different nerve. Thus, in the case of an epithelioma of the tongue, the pain, though perhaps most acute in the region supplied by the lingual nerve, is nevertheless frequently referred to the ear along the course and distribution of the chorda tympani.

The pain is more or less continuous, often associated with exacerbations, but seldom paroxysmal. The patient frequently complains of heat and tenderness over the areas supplied by the nerve in question and, in almost every instance, there are points of special tenderness corresponding as a rule to the emergence of the nerve-trunk through some osseous foramen. Again, some relief may be obtained by the application of pressure over the site of that foramen. For example, neuralgia dependent on antral empyema is most acute in the region of the infra-orbital foramen, and relief may be experienced by pressure applied over that foramen.

In the event of failure to discover an exciting cause, some difficulty may be experienced in coming to a correct conclusion as to whether the case belongs to the minor types of neuralgia, or should be relegated to the more serious group of neuralgia major (tic doloreux). In general, however, the neuralgias minor may be distinguished from the major variety by the following features:—

(1) The presence of some detectable forms of nerve-irritation. In the neuralgias major there may be no such cause.

(2) The relief of symptoms on the successful treatment of the cause.

(3) The relative absence of those paroxysmal attacks which are so typical of neuralgia major.

(4) The infrequence of severe vaso-motor, trophic, and sensory changes in the regions supplied by the nerve affected. Such changes are more or less constant in neuralgia major.

(5) The wide distribution of the pain and its reference to other nerves, with no clear line of demarcation from neighbouring areas supplied by totally different nerves. In neuralgia major the pain, though often involving both second and third divisions of the fifth nerve, is referred to the areas supplied by those nerves only, with a clear line of demarcation from neighbouring regions.

In cases of neuralgia of doubtful origin one can only observe the effect of treatment and be guided by the results obtained.

Treatment.

The source of the neuralgia requires primary consideration. When this has been rectified the patient should be treated after general medical principles. In the event of failure at relief, we have two other strings to our bow—alcohol injections, and neurectomy of the nerve involved. Alcohol injections are dealt with later. Neurectomy—after Thiersch’s method of avulsion—is greatly preferable to all the older methods of neurotomy, nerve-stretching, and nerve-division. These older methods brought about in their train but transitory alleviation of pain.

Neurectomy of the inferior dental nerve.

A transverse incision is made through the skin and subcutaneous tissues at the level of junction between horizontal and vertical rami of the jaw, extending from the anterior border of the vertical ramus to the posterior border of the same. The tissues are retracted and the masseter muscle exposed. The muscle fibres are split in the vertical direction and the bone laid bare. A ¹/₂ inch trephine is applied, and a disk of bone removed so as to expose the inferior dental nerve at its entrance into the inferior dental canal. The nerve is freed from the corresponding artery, divided at the centre of exposure, and the two ends seized with forceps, twisted and avulsed in such a manner as to destroy and remove the maximum number of nerve-fibres. The disk of bone is replaced, the muscle fibres brought together with a few catgut sutures, and the margins of the skin incision approximated.

Exposure of the infra-orbital nerve.

A curved incision is made through the skin and subcutaneous tissues parallel to and below the infra-orbital margin, the tissues retracted, and the small muscles overlying the infra-orbital foramen divided or retracted so as to allow exposure of the foramen. The nerve is isolated and divided. The peripheral end is seized with forceps and avulsed. The central end may be treated after similar fashion, or, preferably, again exposed in the infra-orbital groove or canal, the tissues being peeled away from the floor of the orbit and the nerve sought for as it traverses the infra-orbital canal. With this object in view, it may be necessary to gently break away the osseous roof of the canal before the nerve can be exposed. It is then lifted up with a small hook, drawn through the infra-orbital foramen, seized with forceps, and avulsed in such a manner as to be torn away somewhere in the region of the spheno-maxillary fossa. The wound is then sewn up.

Exposure of the supra-orbital nerve.

The nerve is exposed through a curved incision parallel to the supra-orbital margin, and so planned as to be concealed by the eyebrow. The fibres of the orbicularis palpebrarum are separated and the foramen identified. The nerve is separated from its artery, divided, the peripheral portion avulsed, and the central portion again exposed as it courses along the roof of the orbit. For this purpose the tissues of the upper lid are detached from the supra-orbital margin, the nerve delivered with the aid of a small hook, brought out through the foramen, and avulsed in such a manner as to be torn away somewhere in the region of the sphenoidal fissure. The wound is then sewn up.

NEURALGIA MAJOR

Neuralgia major originates most commonly in the third division of the nerve, less frequently in the second, and rarely in the first. Whichever division be primarily affected, there is a very general tendency for other branches to become involved, and this in a very definite way—the pain spreading centrally from the nerve first involved, radiating to other nerve-trunks so soon as they shall be reached. Thus, pain originating in the inferior dental branch of the third division spreads to the lingual and other branches of that division and then involves the second division. Fortunately, whether the trouble originates in the third or second divisions, the ophthalmic tends to escape or to become less seriously involved—a fortunate circumstance considering the terrible conditions associated with neuritis of that nerve, the disastrous results on cornea, conjunctiva, &c.

The disease is undoubtedly of a progressive nature, originating without rhyme or reason. It seldom becomes evident before the ages of 45 to 55, affecting both rich and poor alike.

Wilfred Harris[69] collected 265 cases, and showed that the disease was slightly more common in men than in women—144 to 131. There appeared to be some predilection for the disease to involve the right side in preference to the left—179 to 80. In 6 cases the affection was bilateral.

Trigeminal neuralgia does not in itself lead to fatal results, but the continuous pain, the want of sleep, and the difficulty experienced in taking sufficient nourishment soon reduce the patient to such a miserable condition that, unless relieved by the surgeon, amelioration is sought in morphia or release in death.

Before proceeding further it will be convenient to enumerate certain points aiding in the differential diagnosis between the true and hysterical forms of trigeminal neuralgia.

True Neuralgia.	Hysterical Neuralgia.
Patient old, probably over 50, and more commonly of the male sex.	Patient young, more commonly of the female sex.
Pain paroxysmal.	Pain severe for long periods together.
Vaso-motor, trophic and sensory changes common.	All these changes very rare.
Pain strictly unilateral and constant in site.	Pain variable in distribution, radiating irregularly to the opposite side of the face.

The pathology of tic doloreux is most obscure. The parts requiring examination are the peripheral nerve-trunks, the ganglion, the sensory root, and the central nervous system. The last two regions may be excluded, not only on the ground that research has failed to show any constant structural changes, but also because the removal of the ganglion may be regarded as curative of the disease. The ganglion itself and the peripheral nerve-trunks remain for investigation.

In the peripheral nerve-fibres no constant material changes have been observed. The epineurium, on the other hand, is almost invariably shrunken and sclerosed. Considerable stress might be laid on this fact unless it were also taken into consideration that the nerves were examined in patients who had suffered from major neuralgia for prolonged periods of time. Similar changes have also been observed in patients who have never exhibited neuralgic symptoms.

In the ganglion itself the following changes have been observed:—(1) arterio-sclerosis; (2) alteration in the character of the nerve-fibres traversing the ganglion; and (3) adhesions between the ganglion and the surrounding parts. All these changes, however, are so inconstant that but little importance can be attached to them.

At the present time there is a disposition to regard trigeminal neuralgia in the light of an ascending neuritis, originating peripherally and ascending towards the Gasserian ganglion. Sir Victor Horsley first pointed out that the ganglion acts as a barrier to the further upward spread of the affection. This is proved by the success obtained in the removal of the ganglion.

Symptomatology.

Pain.

The onset of pain may be preceded by premonitory symptoms such as tinglings, throbbings, and burning sensations in the parts subsequently involved, whilst, in the earlier stages of the disease, the pain may be more or less localized to the site of emergence of the nerve from an osseous foramen.

In the earlier stages also the attacks, though severe, are paroxysmal, of short duration, perhaps not lasting more than half a minute, and definitely localized to some special nerve-trunk. During the periods of remission the patient feels quite well. Gradually the pain increases in severity, the periods of remission shorten, and the pain in its distribution becomes more widespread, the neuritis—or whatever the process may be—spreading centrally and radiating along the course and distribution of such branches of the nerve as shall be encountered.

Paroxysms are a marked feature, occasionally of so severe a nature that the patient falls to the ground as if struck by lightning, recovering after a variable period of time.

In the later stages of the disease the pain may be almost continuous, and the condition of the patient is truly miserable.

The attacks are often ushered in by the slightest stimulus—talking, mastication of food, draughts, emotion, &c.—and, in order to avoid the occurrence as far as possible, the patient abstains from talking, dreads eating, &c. Dribbling from the mouth may be observed in those cases in which the patient finds some relief in keeping the mouth open. It is also frequently seen during the height of the paroxysm. At such stages the patient is collapsed, with feeble pulse, shallow respiration, the temperature subnormal, and the skin clammy. The attacks occur both during the day and the night, sleep fails, and the body nutrition suffers.

The site at which the pain originates can often be fixed by the patient himself. Occasionally relief may be attained by pressure applied over some particular part, by heat or by cold, or by some other method discovered by the patient himself.

The attacks are often accompanied by twitchings of the muscles supplied by the facial nerve, and, according to some investigators, by fibrillary twitchings of the muscles of the region affected.

In the later stages, wasting of the muscles may be observed.

Vaso-motor and trophic changes.

The skin and mucous membrane supplied by the nerve involved become hyperÆmic and hyperÆsthetic, and, in the more chronic cases, these changes may be associated with oedema of the subcutaneous tissues—the clinical picture now closely resembling that observed in some cases of angio-neurotic oedema.

Other symptoms of similar nature are herpes, increased salivation, furred tongue (on the side of the lesion), sweating of the skin, lacrimation, conjunctivitis, and keratitis.

General decline in health.

This depends, not only on the difficulty experienced in taking sufficient nourishment, but also on the moral effect produced by the more or less continuous pain. In the more severe cases emaciation is rapid.

Treatment.

1. Therapeutic remedies. The following drugs have been recommended.

Quinine, in large and increasing doses.

Arsenic, given in a similar fashion.

Gelsemium, in toxic doses, every few hours until tinglings in the fingers and nausea show that the drug has been pushed far enough (Sir Victor Horsley).

Methylene blue, in three-grain doses (Sir Watson Cheyne).

Iron, antipyrin, strychnine, cannabis indica, &c.

Morphia. This drug is undoubtedly beneficial in its results, but the habitual use thereof is strongly contra-indicated, not only because of the temporary benefit received, but also because of the necessary increase in the quantity required to alleviate the pain. If persistently used the patient gradually develops the morphia habit.

Some of these remedies suffice for the neuralgias minor, but with regard to their action in cases of neuralgia major, their effect may be summed up as follows: ‘True tic doloreux has been the therapeutic despair of most physicians and surgeons,’[70] and ‘too often the operation is put off till the patient is addicted to the morphia habit, depleted in strength and vitality by drugs, sleepless nights, and years of intense suffering’.[71]

Until quite recently, with the exception of these medicinal remedies, the only other methods at our disposal in the treatment of trigeminal neuralgia were Gasserian ganglion removal and other intracranial operations on the three divisions of the fifth nerve. In 1906, however, SchlÖsser[72] of Munich advocated the injection of alcohol into the region of those foramina at the base of the skull through which the nerve trunks emerged. As the result of these injections it was stated that, although some slight degree of cutaneous anÆsthesia frequently resulted, yet that it was usually of an unimportant and transient character, and that the pain subsided and finally ceased, remaining absent for a variable period of time, usually about ten months. In the event of recurrence the injection was repeated, each period of recurrent pain being less intense and less prolonged, whilst the periods of remission increased proportionately.

Whilst it is clear from the results obtained by those who have followed in SchlÖsser’s footsteps, that alcohol injections are, as a rule, reasonably satisfactory, yet it must be clearly understood that beneficial results are not always observed, and that in the event of failure the more radical intracranial operations must be carried out.

The technique of alcohol injections.

Question of anÆsthetic. Freezing of the skin or other method of local anÆsthesia suffices to allow of the painless introduction of the needle. A general anÆsthetic should be avoided wherever possible, as the burning sensation experienced by the patient when the nerve-trunk is encountered greatly assists the accuracy of introduction.

The needle. The needle should be stout—10 cm. long, 1·5 cm. in diameter, and graduated in centimetres up to 5 cm., and provided with a blunt stilette.

Introduction. The skin is cleansed, the stilette slightly withdrawn, and the needle introduced. After puncture of the skin the stilette is pushed home, all further introduction being carried out with the blunt advancing point. When in position, the stilette is withdrawn, and a glass syringe, ready filled with alcohol, fitted to the needle and the injection made.

The solution. Purves Stewart recommends the injection of 1-1·5 c.cm. of the following solution:—

Beta eucaine, 2 grains
Absolute alcohol, 6 drs.
Distilled water to the ounce.

Wilfred Harris advises 90 per cent. alcohol, preceded by a 2 per cent. solution eucaine. He urges that two or three drops should be injected slowly, and if the needle be correctly placed a sharp burning pain will instantly be felt over the area of the distribution of the nerve, lasting fifteen seconds or so and then dying away. Two or three more drops are then injected, and thus ‘a few drops at a time, from 1 to 1·5 c.cm. are injected, the pain produced with each succeeding push of the syringe being less and less’.

To reach the foramen ovale (third division), the needle is introduced through the cheek behind the last molar tooth, at the lower border of the zygoma, at a point 2¹/₂ cm. in front of the descending root of the zygoma. The blunt needle penetrates the masseter muscle and the posterior part of the temporal muscle. It is then directed backwards and slightly upwards till it impinges on the skull at the external pterygoid plate. It is then pushed on, upwards and backwards, till it enters the foramen ovale at a depth usually of about 4 cm. from the zygoma. In case of difficulty in passing the needle through the sigmoid notch of the jaw the mouth should be widely opened.

If the needle be directed too low it may penetrate the pharyngeal wall or the Eustachian tube; if too far back, the middle meningeal artery.

To reach the foramen rotundum (second division)—a rather more difficult procedure—it is necessary to find the posterior border of the orbital process of the malar bone, prolonging this line downwards to the lower border of the zygoma and inserting the needle ¹/₂ cm. posterior to this point. The needle is pushed horizontally inwards and the point directed slightly upwards, the foramen being reached in the pterygo-maxillary fossa at a depth of about 3 cm. from the zygoma. The needle, for an average-sized skull, should never penetrate deeper than 5 cm. The structures pierced are the anterior fibres of the masseter and the buccinator muscles. If directed too horizontally, the needle will pass below the nerve and reach the spheno-palatine region; if too high, the sphenoidal fissure may be reached and the branches of the third nerve damaged, causing diplopia and dilatation of the pupil.

To reach the sphenoidal fissure (first division), the needle is introduced at the outer margin of the orbit, close within the fronto-malar articulation, and passed along the outer wall of the orbit to a depth of 3¹/₂ to 4 cm.

Needless to say, it is essential that these injections to the basal foramina should only be carried out in the first instance after experimentation on the cadaver.

In each case a single injection may suffice, but as a general rule it is advisable to repeat the process after two or three days, and again at longer intervals. It is not necessary that the nerve-trunks should be pierced, but better results are obtained by so doing. The surface area to which the particular nerve-trunk is distributed immediately becomes anÆsthetic, remaining in that state till the effect of the injection shall have passed off. The masticatory muscles are paralysed. The injection may be followed by paresis of the facial muscles, by oedema of the lower lid, and by hÆmatomata. These last-named results are, however, transitory.

Results.

SchlÖsser, who injects 15 to 20 minims of an 80 per cent. solution of alcohol, reported in 1907 that he had treated 123 cases, the average period of relief from pain being ten and a half months.

Wilfred Harris[73] reported on 38 cases, 31 of which were completely relieved for periods varying from two to eleven months. In a more recent communication he reports on 86 cases, in only 3 of which was no relief obtained. In 7 cases the injection was made into the ganglion itself, in anticipation of more permanent results.

Operative procedures.

Intracranial procedures for trigeminal neuralgia were formerly associated with so high a rate of mortality that they were not regarded with favour. Of recent years, however, as the result of the general improvement in technique, it has been clearly demonstrated that, in experienced hands, ‘the ganglion can be readily exposed, hÆmorrhage and shock need no longer be considered elements of danger: the risks of the operation are only those associated with every major operation. Recovery from the effects of the operation is rapid; the patients are frequently up and about on the third or fourth day, and the ultimate results are, to say the least, most gratifying to the patient and to the operator.’[74]

The following operations require consideration:—

1. Intracranial resection of the second and third divisions of the fifth nerve (AbbÉ’s operation).

2. Operations for the removal of the whole or part of the Gasserian ganglion (Hartley-Krause operation and its modifications).

3. Operations on the sensory root of the ganglion (Frazier’s operation).

Intracranial resection of the second and third divisions of the fifth nerve and operations on the ganglion itself resemble one another so closely in their preliminary operative stages that they may be considered together. After the usual preparatory treatment—in which the shaving process may be confined to the temporal region—the incision, commencing well above and behind the external angular frontal process, passes backwards below the level of the temporal crest and terminates immediately in front of the tragus of the ear. The front part of the incision, as depicted in Fig. 91, is prolonged too far downwards. It should not be carried further forward than the anterior margin of the hairy scalp, any further downward prolongation tending to involve that branch of the facial nerve which is distributed to the anterior belly of the occipito-frontalis muscle.

The incision, carried out methodically, first involves the skin only, pressure being applied by the surgeon on the one side and his assistant on the other, so as to control bleeding. All divided vessels are at once clamped. The operation may be a prolonged one, and in its later stages bleeding from meningeal vessels and emissary veins may not be so readily controlled. It is essential, therefore, that the earlier stages should be as bloodless as possible.

The temporal fascia is next incised—slightly below the line of the skin incision. Finally, the temporal muscle is divided—again at a lower level than the fascial incision. Skin, fascia, and muscle are then turned down to a zygomatic base. Some surgeons split the temporal muscle in the direction of its fibres, a course, however, that tends somewhat to cramp the operative field.

The trephine is applied to the bone, the surgeon aiming at striking the angle between the anterior and posterior branches of the middle meningeal artery. The bone-disk is removed. With the aid of craniectomy forceps the bone is nibbled away, more especially in the downward direction towards the base of the skull. It is essential that the operator should get down as low as possible, for the lower the line of attack the easier the approach to the ganglion and the less the damage incurred by the brain (from retraction).

The opening in the bone, oval in shape, should present a diameter in the vertical direction of about 1 to 1¹/₄ inches, and an antero-posterior diameter of about 1¹/₂ inches.

The dura is stripped away from the base of the skull, partly with the fingers and partly with the blunt dissector, and a flat, slightly malleable retractor introduced along the floor of the middle fossa, the dura and overlying temporo-sphenoidal lobe being gently lifted upwards. The surgeon should take upon himself the responsibility of retracting the brain, holding that instrument with the one hand and working inwards with the other, directing his course towards the foramen spinosum (middle meningeal) and foramen ovale (third division of the fifth nerve).

During this stage hÆmorrhage, derived mainly from the branches of the middle meningeal, is often troublesome. It may be controlled by the insertion of dry or wet gauze—in the latter case the gauze is soaked in saline solution or sterilized water (at a temperature of about 110° Fahrenheit)—or by the introduction of cotton-wool plugs to each of which a silk thread is attached, for the purpose of facilitating their final removal.

The middle meningeal artery acts as a guide to the foramen spinosum, a foramen that lies immediately posterior and external to the foramen ovale. In many cases the position of this artery so hampers the operator in his manipulation that ligature is demanded. For this purpose Cushing’s silver ‘clips’ will be found most serviceable. One clip is applied to the artery immediately after its entry into the skull, the other a short distance above, the vessel being divided between the two (see Fig. 6).

The foramen ovale is then identified, the dura being stripped away from the nerve trunk by blunt dissection. The surgeon then works inwards and forwards to the second division of the nerve and its foramen, the foramen rotundum. HÆmorrhage, in this case derived from emissary veins, may again be troublesome. Considerable perseverance is required, and, although each attempt at further separation of the dura from the bone entails more oozing, the difficulties—except in the most exceptional cases—may be overcome.

The second and third divisions may now be resected. For this purpose it is essential that the two nerves should be exposed from the point of their exit from the skull right up to the margin of the ganglion. Their dural coat seldom requires to be incised with the knife, the membrane being readily stripped away with the blunt dissector. When fully exposed, the nerve trunks are picked up with a blunt aneurysm needle and divided in two places, flush with the basal foramina and close up against the ganglion. The intermediate parts are removed.

To prevent regeneration of nerve fibres—with consequent return of symptoms—the basal foramina are blocked up with small ivory pegs—well driven home—or with amalgam.

All gauze plugs are removed, the field of operation well dried, and dura and brain allowed to fall back into position. The wound is closed, if possible without drainage. In the event of considerable oozing a cigarette drain should be inserted for twenty-four hours. The scalp-flap is sewn up, skin, muscle, and fascia being united separately.

Removal of the Gasserian ganglion. There is some divergence of opinion as to whether it is necessary to remove the ganglion entire or whether it suffices to resect the lower two-thirds—that part through which the fibres of the second and third divisions course—the upper third being left intact. This latter course is advocated by Jonathan Hutchinson on the grounds that (1) the first division is but rarely involved in the neuralgic process, (2) its inclusion in the process of removal entails some risk to the eye—conjunctivitis, keratitis, and sloughing of the cornea, and (3) resection of the lower two-thirds of the ganglion, when carried out in suitable cases, is but rarely followed by the development of neuralgia in the first or ophthalmic trunk. Added to these facts, it must be admitted that the complete removal of the ganglion is associated with added operative risk—wounding of the cavernous sinus and injury to the third, fourth, and sixth nerves.

The Gasserian ganglion lies in the cavum Meckelii, a depression on the anterior aspect of the petrous portion of the temporal bone, and is situated between the two layers of dura mater, the stronger on the upper or cerebral side, the weaker between it and the bone. Under the pathological conditions often existent in cases of trigeminal neuralgia, considerable adhesion may be present between the ganglion and its enveloping coats. Consequently, its complete exposure is often a matter of considerable difficulty. The dura must be stripped away from the outer aspect of the ganglion, firstly by dividing the membrane along the border of the ganglion between the site of emergence of the second and third divisions, and then by blunt dissection.

The ganglion and its efferent branches being exposed, resection of the lower two-thirds may be carried out. The second and third nerve trunks are severed flush with the basal foramina, traction applied, and the lower portion of the ganglion resected.

During the final stages, the manipulations of the operator are again likely to be obscured by venous oozing and by the discharge of some cerebro-spinal fluid. Patience, careful application of gauze plugs, and good illumination of the field of operation are required to overcome these difficulties. In some few cases the bleeding has been so profuse that the operation has had to be abandoned for the time being, a fresh attempt being made some days later. This course should, however, rarely be necessary.

Similarly, if the operator should deem it necessary to remove the whole ganglion, this procedure may now be carried out. The posterior part of the ganglion is exposed, together with its sensory root. This root is hooked forward with a small blunt-pointed hook and then divided. Traction is applied to the ganglion and it is turned forwards, the three terminal divisions being divided one after the other with the minimum risk of injuring the cavernous sinus.

Modifications of the Hartley-Krause operation.

With the object of obtaining further manipulative room, some surgeons recommend the formation of an osteoplastic flap. This method should never be adopted. It is quite unnecessary, it prolongs the operation, and entails more deformity. Others advise division of the zygoma, both in front and behind, with downward displacement of the intermediate portion. Burghard[75] recommends division and downward displacement of the zygoma together with section of the coronoid process, this process being turned upwards together with its attached temporal muscle.

From my own experience, I should regard all these modifications as quite unnecessary, the Hartley-Krause operation permitting an adequate operative field. The deformity resulting from all these more extensive procedures must also be taken into consideration. The lines of incision in the Hartley-Krause operation are more or less concealed by the hairy scalp.

Operations on the sensory root (Frazier’s operation).

Charles Frazier advocates the ‘physiologic extirpation’ of the sensory root of the ganglion. The advantages claimed over other methods are as follows:—

1. Control of hÆmorrhage and avoidance of risk of injury to the cavernous sinus. The ganglion receives its main blood-supply from below. Division of the sensory root leaves the base of the ganglion undisturbed, and this cause of free bleeding is removed. With respect to the cavernous sinus, the operation is confined to the root of the ganglion and consequently the sinus is in no wise concerned.

2. Simple technique. The operation of division of the sensory root is complete before the difficulties common to extraction of the ganglion have commenced.

3. Avoidance of injury to adjacent structures. The cavernous sinus is not touched; the sixth nerve, which is intimately related to the ophthalmic branch, is not exposed; and the motor-fibres which, passing beneath the ganglion, join the third division outside the skull, and which are almost necessarily injured in the ganglionic operation, may, in division of the sensory root, escape implication.

4. Reduction in the rate of mortality. The operation is said to be more economical of time, to entail less hÆmorrhage, and therefore to be less dangerous.

5. Absence of ocular changes. After division of the sensory root ocular changes are absent, due in part to the fact that the ocular nerves are left intact, and also to the probability that ‘sympathetic fibres pass to the eye after entering the trigeminal nerve through the Gasserian ganglion’ (Spiller).

In the consideration of these advantages it should be noted that they are mainly directed against procedures in which complete extirpation of the ganglion is attempted, and are of less weight when contrasted with the partial excision advocated by Hutchinson.

Frazier’s operation[76] on the sensory root.

‘A horse-shoe shaped incision is made, beginning at the middle of the zygoma and terminating a little below the apex of the lobe of the ear (see Fig. 91). The musculo-cutaneous flap is made purposely a little larger than the opening in the skull. An opening is made in the skull with a diameter not exceeding 3 cm. and extending down as far as the infra-temporal crest. The dura is separated from the base of the skull with a blunt retractor as far as the foramen spinosum. The middle meningeal artery is ligatured and the dura mater incised directly over the third division at the margin of the foramen ovale and separated from the upper surface of the ganglion as far back as the sensory root. The latter is picked up with a blunt hook, grasped with forceps and divided or avulsed. It is necessary only to expose the posterior portion of the ganglion; the second and third divisions of the fifth, the structures on the inner side of the ganglion, and the cavernous sinus, are left undisturbed.’

Choice of operation.

There are both advantages and disadvantages to each of the various operations enumerated. There are also other operations. From my own experience I have come to the conclusion that the two operations of choice are resection of the second and third divisions of the fifth nerve and division of the sensory root. The former of these two operations is carried out when the general condition of the patient is not altogether satisfactory, presuming, of course, that the neuralgia is limited to those divisions of the nerve. Under more favourable circumstances excellent results are obtained by exposure and division or resection of the sensory root, with, I think, the minimum risk.

The results obtained by operation.

The prevailing impression that these operations are associated with a high mortality is totally incorrect. From my own experience and from numerous recorded cases, the mortality may be estimated at not more than 5 per cent.

The extent of anÆsthesia resulting varies according to the nature of the operation. Thus, if the upper part of the ganglion be spared or the operation confined to the second and third divisions, the upper lid, conjunctiva, cornea, and forehead escape. In any case, taste is but little impaired, the posterior part of the tongue being supplied by the glossopharyngeal and the tip and sides by the chorda tympani. In all cases, except perhaps in Frazier’s operation, the motor fibres which accompany the third division are almost always divided, with consequent paralysis of the corresponding masseter, temporal, and pterygoid muscles. The degree of discomfort and deformity resulting from such anÆsthesia and paralysis is, however, not very considerable, and in contrast with the relief from the terrible pain, of very little import. It is, as Jonathan Hutchinson says, the price which the patient has to pay for the cure of the neuralgia.

With respect to recurrence of pain, there is every reason to believe that the resection of the sensory root and the complete removal of the ganglion are never followed by recurrence of pain. With respect to Jonathan Hutchinson’s and AbbÉ’s operations, there is some divergence of opinion. There would appear to be some cases recorded in which the symptoms have recurred—often many years later. With regard to Hutchinson’s operation I have no personal experience, but it is stated that in some few cases the pain has recurred in the first division. I believe, however, that I am correct in stating that this is denied by Hutchinson from the experience based on his own cases. As regards AbbÉ’s operation, recurrence may take place if the basal foramina are not completely occluded, some few nerve fibres growing through the foramina on either side of the occluding medium. Such complications have not taken place in the cases in which I have carried out this operation.

Besides experiencing immediate and complete relief from pain, the patients sleep well, eat well, and rapidly convalesce. For some two or three days they may suffer from some headache, presumably due to the necessary manipulations of the brain, but this, besides being relieved by drugs, soon passes off. Frequently, the patients are up and about within a few days.

Whatever the nature of the operation, the greatest care must be taken to protect the eye on the affected side—the conjunctival sac is washed out daily with a mild boracic solution and the cornea guarded from exposure to air and dust by means of a glass covering fastened round the forehead. This appliance should be worn for two or three weeks.

The main difficulties and dangers of operation are as follows:—

1. HÆmorrhage (from middle meningeal artery and cavernous sinus).

2. Infection.

3. Shock.

4. Ocular complications.

5. Later after-results—insomnia, restlessness, impairment of memory, aphasia, and hemiplegia—all of which are dependent either on rough handling of the brain or lighter handling of an already diseased brain.