Chapter 5
WOUNDS OF THE NERVES
By reason of their form, their mobility, their elasticity, they escape to a certain extent the action of bullets, especially when these last are pointed and have only a small degree of velocity. The lesions are contusion, partial abrasion, perforation, total abrasion.
1. Contusions. -- We find two degrees of contusion: In the first the contusion is trifling. The nerve does not appear to have suffered externally ; in its interior a few fibres have been destroyed. In the second degree the external form of the nerve has changed, it is contracted at the place where the bullet struck, above and below it shows a spindle-shaped dilatation caused by the forcing back of the myelin. The neurilemma is separated.
2. Partial Abrasions. -- These are more or less regular indentations with forcing back of the myelin.
3. Perforations.--The bullet has pierced the centre of the nerve in a linear manner, leaving the lateral portions apparently intact (Freyer). The lesions are not seen exclusively in the largest nerves. Nerves of a smaller calibre - the median, the musculo-spiral, the ulnar, with a diameter less than that of the projectile - are also perforated.
We do not know the degree of frequency of this curious variety of traumatism; it was not produced by the old bullets, and its frequency still has to be determined.
4. Abrasions: Total Division . - In these cases the nerve shows a solution of continuity. Its extremities are reduced to pulp and the myelin is forced back (bullets, shell splinters).
Signs of Wounds of Nerves - Disturbance of feeling, of movement (paralysis, cramps, contractions); disturbances taking place at a distance through reflex action, these may show themselves immediately or a little while after the traumatism; they are all too well known for them to delay us. It will be sufficient for us to point out that immediate pain, either localized or at a distance, is rare (less than half the cases), and that immediate trouble at a distance must be referred to the hysterical group of disorders.
Consecutive disturbances are those of feeling, of motility, of nutrition, or they may depend on a processes of irritation.
If the aseptic evolution of wounds of nerves by firearms takes place without important phenomena of irritation, in cases of infection, of acute neuritis, both the localized and the radiating pain is acute, tenacious, intermittent, or continuous, and sometimes accompanied by fever, spasm, and contraction. The neuritis, when it becomes chronic, may assume the ascending form, and extend even to the medullary roots; this, however, is less frequent than it used to be. In some cases the pains bring on a regular sensorial tetanus (Weir Mitchell). Hyperaesthesia is extreme, and is awakened by the slightest contact, and in a far greater degree at the slightest fear of contact. Causalgia, glossiness of the skin, and acute disturbances of nutrition due to neuritis, are well known ; but let us remind medical men that in extreme cases, even well-marked cerebral disturbance has been remarked.
Although far more rare nowadays, thanks to the aseptic evolution of many of the wounds, neurotic phenomena are none the less complications that are to be, feared ; there fore we should strive to prevent thein or to limit them by devoting particular and special care to wounds occurring in the regions of the large nerves.
General diagnosis of wounds of the nerves by projectiles is in most cases easy ; but, when it is a question of determining the nature of the lesion, the solution of the problem becomes difficult, often impossible. A great deal of quite unjustifiable interference is thus explained.
Treatment.-- The treatment, which not long ago was reduced to the symptomatic indications, has been enriched at the end of recent wars by improvements adapted from the technique of everyday surgery. In order to appreciate their full value we will revert to what we recently said on the subject before the Academy of Medicine (February 24, 1914).* Report on a work by Professor Laurent of Brussels, Aneurysms and Wounds of Nerves in War Surgery. 0. C.
This technique, we wish first to point out, concerns specially the work of the surgeons at the rear. At the front any intervention seems to be contra-indicated, were it only on account of the extreme difficulties of the diagnosis, of the complexity of a deceptive and excessive symptomatology, which takes time to be elucidated ; therefore at the front we must content ourselves with dressing the wound and avoiding all irritation.
It is all the more indicated to make use of this technique at the rear, inasmuch as surgery of the nerves is not so urgent with regard to the time of intervention as surgery of the arteries; and inasmuch as in the hospitals at the rear the surgeon can undertake these operations without being hurried, at the hour he chooses, and under the best surrounding conditions. One of the conditions for successful operation in these cases is very strict asepsis.
We should certainly hesitate to put sutures into wounds threatened with infection. It is far preferable to wait for their cicatrization before intervening.
On the other hand, the large nerves are nearly always wounded at the same time as the arteries, of which they are the satellites ; and the surgeon naturally has his attention drawn to their injuries only at a consecutive period when he operates on the accompanying aneurysm, the treatment of which would plainly occupy a more important place than that of the nerve lesion.
"The lesions presented by nerves injured by projectiles are, we remarked, at the same time less favourable for successful operation and more favourable for spontaneous cicatrization than are wounds we see in everyday practice. In these last the nervous trunks have nearly always been divided by an instrument or by something sharp; they have not experienced loss of substance, but, if healing has taken place with formation of a neuroma, its excision is not an addition to the loss of substance resulting from the primary traumatism. This consideration, which up to now has not been insisted upon, should not be lost sight of by those who wish to form an appreciation of the indications, the degree of usefulness, and the results of operative interference.
"Let us discuss their expediency, first in cases of slight contusions. Although these show originally sensori-motor disturbances which might put us on the wrong scent with regard to their real prognosis, the continuity of the nerve is not interrupted in this instance.
"In extensive contusions the nerve is deeply injured; the forced-back myeline often gives rise to the immediate formation of a small neuroma above the point of injury. Here, again, however, the continuity of the nerve is not interrupted. Why, then, should we operate? Again, if we intervene a little time after the traumatism, to what extent could we carry the loss of substance necessi tated by the refreshing of the ends of the nerve before suturing ?
"Amongst Abrasions, some are slight, and only involve to very small extent the circumference of the nervous trunk. Could we but recognize them clinically, no one would dream of meddling with them. There are some, however, that are complete or nearly complete, and the forcing back of the myeline is added to the loss of substance. At the period when one might think of an operation, one must look forward to having to treat a pretty extensive loss of substance joined to a nervous deterioration, which itself is rather large, and has undefined limits. Sutures might be difficult to obtain, and their success problematical. These lesions, which are but little circumscribed, are especially dangerous when the nerve has been injured by a projectile having a very great velocity - that is to say, one that has been fired from a short distance.
"In Perforations, any immediate intervention would be inexplicable. Freyer, face to face with three wounded men showing such lesions, abstained from all surgical interference. Really, one does not see what other course he could have followed.
"It may be gathered from these statements that it seems very difficult to recommend nowadays any active treatment for wounds of nerves by projectiles within a short period from the occurrence of the traumatism, excepting in those cases where the nerve is pierced by a splinter, this having been discovered in the course of surgical intervention for some other cause.
"Putting aside such cases as these last, we consider it better to allow Nature either to undertake repair, or to show evidence of its incapacity to do so. On the other hand, in presence of this incapacity, every-thing must be tried to help Nature. Surgical therapeutics, the results of which have not as yet been entirely satis factory, offer many methods for us to utilize, such as displacement, suturing at a distance according to Assaky's plan, implantations, and splitting and grafting.
"A nerve compressed by a fibrous band or by a callus in the process of formation should be liberated and transposed; Partial excisions of neuromata should be done, followed by direct suturing ; total excisions of neuromata, also followed by direct suturing; a splinter that has pierced a nerve should be removed; when there is loss of substance, we should have recourse to end-to-end anastomosis."
In order to make a protecting canal for these important elements of repair, we can, following the example of Professor Laurent of Brussels, form a sheath for the nerve in a strip of fascia. This surgeon has chiefly taken his strips from the extensive aponeurosis of the fascia lata. From it lie detaches, in the form of a graft, a square piece of from 3 to 4 centimetres, that he sutures by means of silk or catgut all round the united ends of the nerve.
This way of forming a sheath is only an invitation of the method of Van Lair -- the so-called tubulization. This surgeon made each divided extremity of the nerve penetrate a tube of decalcified bone.
Foratimi (1904) proposed making use of arterial or venous fragments taken from a freshly killed calf; and these pieces were treated by immersion in formol and kept in alcohol.
Two Japanese surgeons, Drs. Hashimoto and Takuoka, during the Manchurian War, made use of the method of Foratimi, and had nothing but praise for it.
The following is the method of preparation to which these surgeons had recourse: Arteries and veins of different sizes are excised with antiseptic precautions from a recently killed calf; they are placed on a glass stick; after hardening in 5 or 10 per cent. formol for forty-cigh hours, they are washed in running water for thirty hours, they are then boiled for twenty minutes, and kept in alcohol at 950. Reabsorption will take place in from two to four months. The same surgeons have also another way of operating, which consists in displacing to a new positionin the thickness of the adjoining muscles nerves that have been sutured. They have obtained excellent results.
In the case of one of his men who had a bayonet wound, and on whom he had incised a neuroma of the median nerve, Dr. Laurent formed a sheath for the nerve from a fresh, quite unprepared piece of the jugular vein of a sheep. A sheath made of a graft was not successful.
The simple proposal made by M. Cunéo seems to have been forgotten. it consisted in making use, for an isolating tubular piece, of a portion of a large superficial vein taken from the patient himself. Perhaps this is the method of the future. (Cunéo, Treatise by Le Dentu and Delbet, article "Nerves".) We may call it an auto-graft. The method presents all the most favourable conditions for its revival, it is always ready to hand, and its asepsis is perfect.
On the whole, the questions dealing with the primary and consecutive treatment of wounds of the nerves have not yet had sufficient light thrown on them. The various forms of treatment are numerous, but their results have not been fully studied. These points are worthy of being taken up and completed during the present campaign.
In dealing with neuritis the surgeon will fall back on sedatives, on neurotomy, and on neurotripsy. We cannot in such cases speak too highly of powerful, extreme, and instantaneous compression made by the thumb on a level with the wound when the nerves are superficial. To this species of neurotripsy we owe some remarkable successes in old cases that had not been ameliorated by division or amputation of the nerves, and this in wounded soldiers who could not possibly be suspected of hysteria. (Delorme, "On the Disappearance of Neuritic Symptoms by Localised and Forcible Compression," Desportes Prize. Journal de Médicine et de Chirurgie Pratiques, June 25, 1896.)