Manual of Surgery Volume I Part 39

[Ill.u.s.tration: FIG. 86.--Diffuse enlargement of Nerves in generalised Neuro-fibromatosis.

(After R. W. Smith.)]

Neuro-fibromatosis is frequently accompanied by _pigmentation of the skin_ in the form of brown spots or patches scattered over the trunk.

The disease is often stationary for long periods. In progressive cases the patient becomes exhausted, and usually dies of some intercurrent affection, particularly phthisis. The treatment is restricted to relieving symptoms and complications; removal of one of the tumours is to be strongly deprecated.

In a considerable proportion of cases one of the multiple tumours takes on the characters of a malignant growth ("secondary malignant neuroma,"

Garre). This malignant transformation may follow upon injury, or on an unsuccessful attempt to remove the tumour. The features are those of a rapidly growing sarcoma involving a nerve-trunk, with agonising pain and muscular cramps, followed by paralysis from destruction of the nerve fibres. The removal of the tumour is usually followed by recurrence, so that high amputation is the only treatment to be recommended. Metastasis to internal organs is exceptional.

[Ill.u.s.tration: FIG. 87.--Plexiform Neuroma of small Sciatic Nerve, from a girl aet. 16.

(Mr. Annandale's case.)]

There are other types of neuro-fibromatosis which require brief mention.

_The plexiform neuroma_ (Fig. 87) is a fibromatosis confined to the distribution of one or more contiguous nerves or of a plexus of nerves, and it may occur either by itself or along with multiple tumours of the nerve-trunks and with pigmentation of the skin. The clinical features are those of an ill-defined swelling composed of a number of tortuous, convoluted cords, lying in a loose areolar tissue and freely movable on one another. It is rarely the seat of pain or tenderness. It most often appears in the early years of life, sometimes in relation to a pigmented or hairy mole. It is of slow growth, may remain stationary for long periods, and has little or no tendency to become malignant. It is usually subcutaneous, and is frequently situated on the head or neck in the distribution of the trigeminal or superficial cervical nerves. There is no necessity for its removal, but this may be indicated because of disfigurement, especially on the face or scalp or because its bulk interferes with function. When involving the ophthalmic division of the trigeminus, for example, it may cause enlargement of the upper lid and proptosis, with danger to the function of the globe. The results of excision are usually satisfactory, even if the removal is not complete.

[Ill.u.s.tration: FIG. 88.--Multiple Neuro-fibromas of Skin (Mollusc.u.m fibrosum, or Recklinghausen's disease).]

_The cutaneous neuro-fibroma_ or _mollusc.u.m fibrosum_ has been shown by Recklinghausen to be a soft fibroma related to the terminal filaments of one of the cutaneous nerves (Fig. 88). The disease appears in the form of multiple, soft, projecting tumours, scattered all over the body, except the palms of the hands and soles of the feet. The tumours are of all sizes, some being no larger than a pin's head, whilst many are as big as a filbert and a few even larger. Many are sessile and others are distinctly pedunculated, but all are covered with skin. They are mobile, soft to the touch, and of the consistence of firm fat. In exceptional cases one of the skin tumours may attain an enormous size and cause a hideous deformity, hanging down by its own weight in lobulated or folded ma.s.ses (pachy-dermatocele). The treatment consists in removing the larger swellings. In some cases mollusc.u.m fibrosum is a.s.sociated with pigmentation of the skin and with multiple tumours of the nerve-trunks.

The small multiple tumours rarely call for interference.

[Ill.u.s.tration: FIG. 89.--Elephantiasis Neuromatosa in a woman aet. 28]

_Elephantiasis neuromatosa_ is the name applied by Virchow to a condition in which a limb is swollen and misshapen as a result of the extension of a neuro-fibromatosis to the skin and subcutaneous cellular tissue of the extremity as a whole (Fig. 89). It usually begins in early life without apparent cause, and it may be a.s.sociated with multiple tumours of the nerve-trunks. The inconvenience caused by the bulk and weight of the limb may justify its removal.

SURGERY OF THE INDIVIDUAL NERVES[6]

[6] We desire here to acknowledge our indebtedness to Mr. James Sherren's work on _Injuries of Nerves and their Treatment_.

#The Brachial Plexus.#--Lesions of the brachial plexus may be divided into those above the clavicle and those below that bone.

In the #supra-clavicular injuries#, the violence applied to the head or shoulder causes over-stretching of the anterior branches (primary divisions) of the cervical nerves, the fifth, or the fifth and sixth being those most liable to suffer. Sometimes the traction is exerted upon the plexus from below, as when a man in falling from a height endeavours to save himself by clutching at some projection, and the lesion then mainly affects the first dorsal nerve. There is tearing of the nerve sheaths, with haemorrhage, but in severe cases partial or complete severance of nerve fibres may occur and these give way at different levels. During the healing process an excess of fibrous tissue is formed, which may interfere with regeneration.

_Post-anaesthetic paralysis_ occurs in patients in whom, during the course of an operation, the arm is abducted and rotated laterally or extended above the head, causing over-stretching of the plexus, especially of the fifth, or fifth and sixth, anterior branches.

A _cervical rib_ may damage the plexus by direct pressure, the part usually affected being the medial cord, which is made up of fibres from the eighth cervical and first dorsal nerves.

When a lesion of the plexus complicates a _fracture of the clavicle_, the nerve injury is due, not to pressure on or laceration of the nerves by fragments of bone, but to the violence causing the fracture, and this is usually applied to the point of the shoulder.

Penetrating _wounds_, apart from those met with in military practice, are rare.

In the #infra-clavicular injuries#, the lesion most often results from the pressure of the dislocated head of the humerus; occasionally from attempts made to reduce the dislocation by the heel-in-the-axilla method, or from fracture of the upper end of the humerus or of the neck of the scapula. The whole plexus may suffer, but more frequently the medial cord is alone implicated.

_Clinical Features._--Three types of lesion result from indirect violence: the whole plexus; the upper-arm type; and the lower-arm type.

_When the whole plexus is involved_, sensibility is lost over the entire forearm and hand and over the lateral surface of the arm in its distal two-thirds. All the muscles of the arm, forearm, and hand are paralysed, and, as a rule, also the pectorals and spinati, but the rhomboids and serratus anterior escape. There is paralysis of the sympathetic fibres to the eye and orbit, with narrowing of the palpebral fissure, recession of the globe, and the pupil is slow to dilate when shaded from the light.

The _upper-arm type_--Erb-d.u.c.h.enne paralysis--is that most frequently met with, and it is due to a lesion of the fifth anterior branch, or, it may be, also of the sixth. The position of the upper limb is typical: the arm and forearm hang close to the side, with the forearm extended and p.r.o.nated; the deltoid, spinati, biceps, brachialis, and supinators are paralysed, and in some cases the radial extensors of the wrist and the p.r.o.nator teres are also affected. The patient is unable to supinate the forearm or to abduct the arm, and in most cases to flex the forearm.

He may, however, regain some power of flexing the forearm when it is fully p.r.o.nated, the extensors of the wrist becoming feeble flexors of the elbow. There is, as a rule, no loss of sensibility, but complaint may be made of tickling and of pins-and-needles over the lateral aspect of the arm. The abnormal position of the limb may persist although the muscles regain the power of voluntary movement, and as the condition frequently follows a fall on the shoulder, great care is necessary in diagnosis, as the condition is apt to be attributed to an injury to the axillary (circ.u.mflex) nerve.

The _lower-arm type_ of paralysis, a.s.sociated with the name of Klumpke, is usually due to over-stretching of the plexus, and especially affects the anterior branch of the first dorsal nerve. In typical cases all the intrinsic muscles of the hand are affected, and the hand a.s.sumes the claw shape. Sensibility is usually altered over the medial side of the arm and forearm, and there is paralysis of the sympathetic.

_Infra-clavicular injuries_, as already stated, are most often produced by a sub-coracoid dislocation of the humerus; the medial cord is that most frequently injured, and the muscles paralysed are those supplied by the ulnar nerve, with, in addition, those intrinsic muscles of the hand supplied by the median. Sensibility is affected over the medial surface of the forearm and ulnar area of the hand. Injury of the lateral and posterior cords is very rare.

_Treatment_ is carried out on the lines already laid down for nerve injuries in general. It is impossible to diagnose between complete and incomplete rupture of the nerve cords, until sufficient time has elapsed to allow of the establishment of the reaction of degeneration. If this is present at the end of fourteen days, operation should not be delayed.

Access to the cords of the plexus is obtained by a dissection similar to that employed for the subclavian artery, and the nerves are sought for as they emerge from under cover of the scalenus anterior, and are then traced until the seat of injury is found. In the case of the first dorsal nerve, it may be necessary temporarily to resect the clavicle.

The usual after-treatment must be persisted in until recovery ensues, and care must be taken that the paralysed muscles do not become over-stretched. The prognosis is less favourable in the supra-clavicular lesions than in those below the clavicle, which nearly always recover without surgical intervention.

In the _brachial birth-paralysis_ met with in infants, the lesion is due to over-stretching of the plexus, and is nearly always of the Erb-d.u.c.h.enne type. The injury is usually unilateral, it occurs with almost equal frequency in breech and in vertex presentations, and the left arm is more often affected than the right. The lesion is seldom recognised at birth. The first symptom noticed is tenderness in the supra-clavicular region, the child crying when this part is touched or the arm is moved. The att.i.tude may be that of the Erb-d.u.c.h.enne type, or the whole of the muscles of the upper limb may be flaccid, and the arm hangs powerless. A considerable proportion of the cases recover spontaneously. The arm is to be kept at rest, with the affected muscles relaxed, and, as soon as tenderness has disappeared, daily ma.s.sage and pa.s.sive movements are employed. The reaction of degeneration can rarely be satisfactorily tested before the child is three months old, but if it is present, an operation should be performed. After operation, the shoulder should be elevated so that no traction is exerted on the affected cords.

#The long thoracic nerve# (nerve of Bell), which supplies the serratus anterior, is rarely injured. In those whose occupation entails carrying weights upon the shoulder it may be contused, and the resulting paralysis of the serratus is usually combined with paralysis of the lower part of the trapezius, the branches from the third and fourth cervical nerves which supply this muscle also being exposed to pressure as they pa.s.s across the root of the neck. There is complaint of pain above the clavicle, and winging of the scapula; the patient is unable to raise the arm in front of the body above the level of the shoulder or to perform any forward pushing movements; on attempting either of these the winging of the scapula is at once increased. If the scapula is compared with that on the sound side, it is seen that, in addition to the lower angle being more prominent, the spine is more horizontal and the lower angle nearer the middle line. The majority of these cases recover if the limb is placed at absolute rest, the elbow supported, and ma.s.sage and galvanism persevered with. If the paralysis persists, the sterno-costal portion of the pectoralis major may be transplanted to the lower angle of the scapula.

The long thoracic nerve may be cut across while clearing out the axilla in operating for cancer of the breast. The displacement of the scapula is not so marked as in the preceding type, and the patient is able to perform pushing movements below the level of the shoulder. If the reaction of degeneration develops, an operation may be performed, the ends of the nerve being sutured, or the distal end grafted into the posterior cord of the brachial plexus.

#The Axillary (Circ.u.mflex) Nerve.#--In the majority of cases in which paralysis of the deltoid follows upon an injury of the shoulder, it is due to a lesion of the fifth cervical nerve, as has already been described in injuries of the brachial plexus. The axillary nerve itself as it pa.s.ses round the neck of the humerus is most liable to be injured from the pressure of a crutch, or of the head of the humerus in sub-glenoid dislocation, or in fracture of the neck of the scapula or of the humerus. In miners, who work for long periods lying on the side, the muscle may be paralysed by direct pressure on the terminal filaments of the nerve, and the nerve may also be involved as a result of disease in the sub-deltoid bursa.

The deltoid is wasted, and the acromion unduly prominent. In recent cases paralysis of the muscle is easily detected. In cases of long standing it is not so simple, because other muscles, the spinati, the clavicular fibres of the pectoral and the serratus, take its place and elevate the arm; there is always loss of sensation on the lateral aspect of the shoulder. There is rarely any call for operative treatment, as the paralysis is usually compensated for by other muscles.

When the _supra-scapular nerve_ is contused or stretched in injuries of the shoulder, the spinati muscles are paralysed and wasted, the spine of the scapula is unduly prominent, and there is impairment in the power of abducting the arm and rotating it laterally.

The _musculo-cutaneous nerve_ is very rarely injured; when cut across, there is paralysis of the coraco-brachialis, biceps, and part of the brachialis, but no movements are abolished, the forearm being flexed, in the p.r.o.nated position, by the brachio-radialis and long radial extensor of the wrist; in the supinated position, by that portion of the brachialis supplied by the radial nerve. Supination is feebly performed by the supinator muscle. Protopathic and epicritic sensibility are lost over the radial side of the forearm.

#Radial (Musculo-Spiral) Nerve.#--From its anatomical relationships this trunk is more exposed to injury than any other nerve in the body. It is frequently compressed against the humerus in sleeping with the arm resting on the back of a chair, especially in the deep sleep of alcoholic intoxication (drunkard's palsy). It may be pressed upon by a crutch in the axilla, by the dislocated head of the humerus, or by violent compression of the arm, as when an elastic tourniquet is applied too tightly. The most serious and permanent injuries of this nerve are a.s.sociated with fractures of the humerus, especially those from direct violence attended with comminution of the bone. The nerve may be crushed or torn by one of the fragments at the time of the injury, or at a later period may be compressed by callus.

_Clinical Features._--Immediately after the injury it is impossible to tell whether the nerve is torn across or merely compressed. The patient may complain of numbness and tingling in the distribution of the superficial branch of the nerve, but it is a striking fact, that so long as the nerve is divided below the level at which it gives off the dorsal cutaneous nerve of the forearm (external cutaneous branch), there is no loss of sensation. When it is divided above the origin of the dorsal cutaneous branch, or when the dorsal branch of the musculo-cutaneous nerve is also divided, there is a loss of sensibility on the dorsum of the hand.

The motor symptoms predominate, the muscles affected being the extensors of the wrist and fingers, and the supinators. There is a characteristic "drop-wrist"; the wrist is flexed and p.r.o.nated, and the patient is unable to dorsiflex the wrist or fingers (Fig. 90). If the hand and proximal phalanges are supported, the second and third phalanges may be partly extended by the interossei and lumbricals. There is also considerable impairment of power in the muscles which antagonise those that are paralysed, so that the grasp of the hand is feeble, and the patient almost loses the use of it; in some cases this would appear to be due to the median nerve having been injured at the same time.

[Ill.u.s.tration: FIG. 90.--Drop-wrist following Fracture of Shaft of Humerus.]

If the lesion is high up, as it is, for example, in crutch paralysis, the triceps and anconeus may also suffer.

_Treatment._--The slighter forms of injury by compression recover under ma.s.sage, douching, and electricity. If there is drop-wrist, the hand and forearm are placed on a palmar splint, with the hand dorsiflexed to nearly a right angle, and this position is maintained until voluntary dorsiflexion at the wrist returns to the normal. Recovery is sometimes delayed for several months.

In the more severe injuries a.s.sociated with fracture of the humerus and attended with the reaction of degeneration, it is necessary to cut down upon the nerve and free it from the pressure of a fragment of bone or from callus or adhesions. If the nerve is torn across, the ends must be sutured, and if this is impossible owing to loss of tissue, the gap may be bridged by a graft taken from the superficial branch of the radial nerve, or the ends may be implanted into the median.

Finally, in cases in which the paralysis is permanent and incurable, the disability may be relieved by operation. A fascial graft can be employed to act as a ligament permanently extending the wrist; it is attached to the third and fourth metacarpal bones distally and to the radius or ulna proximally. The flexor carpi radialis can then be joined up with the extensor digitorum communis by pa.s.sing its tendon through an aperture in the interosseous membrane, or better still, through the p.r.o.nator quadratus, as there is less likelihood of the formation of adhesions when the tendon pa.s.ses through muscle than through interosseous membrane. The palmaris longus is anastomosed with the abductor pollicis longus (extensor ossis metacarpi pollicis), thus securing a fair amount of abduction of the thumb. The flexor carpi ulnaris may also be anastomosed with the common extensor of the fingers. The extensors of the wrist may be shortened, so as to place the hand in the position of dorsal flexion, and thus improve the att.i.tude and grasp of the hand.

_The superficial branch of the radial_ (radial nerve) _and the deep branch_ (posterior interosseous), apart from suffering in lesions of the radial, are liable to be contused or torn is dislocation of the head of the radius, and in fracture of the neck of the bone. The deep branch may be divided as it pa.s.ses through the supinator in operations on old fractures and dislocations in the region of the elbow. Division of the superficial branch in the upper two-thirds of the forearm produces no loss of sensibility; division in the lower third after the nerve has become a.s.sociated with branches from the musculo-cutaneous is followed by a loss of sensibility on the radial side of the hand and thumb. Wounds on the dorsal surface of the wrist and forearm are often followed by loss of sensibility over a larger area, because the musculo-cutaneous nerve is divided as well, and some of the fibres of the lower lateral cutaneous branch of the radial.

[Ill.u.s.tration: FIG. 91.--To ill.u.s.trate the Loss of Sensation produced by Division of the Median Nerve. The area of complete cutaneous insensibility is shaded black. The parts insensitive to light touch and to intermediate degrees of temperature are enclosed within the dotted line.

(After Head and Sherren.)]

#The Median Nerve# is most frequently injured in wounds made by broken gla.s.s in the region of the wrist. It may also be injured in fractures of the lower end of the humerus, in fractures of both bones of the forearm, and as a result of pressure by splints. After _division at the elbow_, there is impairment of mobility which affects the thumb, and to a less extent the index finger: the terminal phalanx of the thumb cannot be flexed owing to the paralysis of the flexor pollicis longus, and the index can only be flexed at its metacarpo-phalangeal joint by the interosseous muscles attached to it. p.r.o.nation of the forearm is feeble, and is completed by the weight of the hand. After _division at the wrist_, the abductor-opponens group of muscles and the two lateral lumbricals only are affected; the abduction of the thumb can be feebly imitated by the short extensor and the long abductor (ext. ossis metacarpi pollicis), while opposition may be simulated by contraction of the long flexor and the short abductor of the thumb; the paralysis of the two medial lumbricals produces no symptoms that can be recognised.