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(ii) The treatment and prognosis of major nerve injury in the adult upper limb
Current Orthopaedics(1999) 13, 9 19 © 1999Harcourt Brace & Co. Ltd
Mini-symposium: Surgical neurology of the upper limb
(ii) The treatment and prognosis of major nerve injury in the adult upper limb
R. Birch INTRODUCTION Precision in diagnosis is the first and essential step in the treatment of any disease or injury and lesions of the peripheral nerves offer the astute clinician an unequalled opportunity to arrive at precise diagnosis on the basis of the history and simple but accurate physical examination with only occasional reference to specific ancillary investigations. This presupposes knowledge of elementary anatomical and physiological principles: perhaps a dangerous assumption! This paper briefly summarizes some aspects of injury of those nerves derived from the anterior primary rami of the fifth, sixth, seventh and eighth cervical and first thoracic spinal nerves and also to the eleventh cranial nerve (the spinal accessory nerve).
DIAGNOSIS
The distinction which must be made lies between the degenerative and non-degenerative lesion. When an axon is cut, changes first described by Waller (1850), ~ and now known as Wallerian degeneration, follow. Distal to the lesion, the axon degenerates and conduction is lost at about three to four days. All function is lost. A particularly important clinical sign of this is the vaso- and sudomotor paralysis from interruption of the post-ganglionic sympathetic fibres. The skin in the territory o f the affected nerve becomes red and dry. There are progressive changes in the target organs, in muscle, skin, blood vessels and the sensory organelles which become irreversible. Muscle denervated for two years or more is lost to function. Of
Rolfe Birch MChir FRCS, The Royal National Orthopaedic
Hospital Trust, BrockleyHill, Stanmore,MiddlesexHA7 4LP, UK
equal significance, however, are the changes which occur proximally after transection of the axon. The proximal portion narrows and, in the parent neurone, there is chromatolysis and retraction of dendrites. 'These processes may continue to actual dissolution of the cell body'. 2 Dyck et al (1984) were able to study the effect of permanent axonotomy in the spinal cord of two patients years after amputation of a lower limb? They found that 'loss of target tissue by axotomy leads to atrophy and then loss of motor neurones'. These central changes are more extreme in more proximal, more extensive and more violent injuries. They are a fundamental factor in prognosis after repair and one important explanation for the harmfulness of delay of nerve repair after such lesions. A classification of nerve injuries introduced by Seddon distinguished between three types of injuries? • neurapraxia (nerve not working) implies a physiological block to conduction but no anatomical disturbance of the nerve; • axonotmesis (axon cutting) in which the axon is severed, its distal portion degenerates, but the basal lamina of the Schwann cell remains intact; • neurotmesis (nerve cutting) describes the lesion where there is interruption of continuity of all elements of the nerve. In neurapraxia, distal conduction persists, the axon has not been cut and it does not degenerate. On the other hand, Wallerian degeneration occurs in both axonotmesis and neurotmesis. Here we have two lesions in which the prognosis is favourable - neurapraxia and axonotmesis - if the cause is removed, and one further lesion - neurotmesis, in which recovery can occur only if the nerve is repaired. We should remember that a favourable lesion may deepen to one much less favourable if the original cause is not dealt
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Current Orthopaedics
with. Recovery is likely for a nerve accidentally encircled by a suture or crushed under a plate if the cause is urgently removed. If the offending cause remains for days or weeks, then a much more unfavourable lesion develops. Nerves crushed in the swollen ischaemic limb or in a tense compartment progress from conduction block to much deeper and much less favourable degenerative lesions. As Bonney stated, 'we on the contrary have tended towards a further simplification: to classification as "degenerative" and "non-degenerative". This, we think, is the manner in which clinicians should regard a nerve injury the first question to be asked is: is this lesion degenerative or non-degenerative'? When a nerve has stopped working and there is a wound over the course of a nerve, then the diagnosis is nerve transection until proven otherwise. The extent of lesion is shown by weakness or paralysis of muscle and by the extent of loss of cutaneous sensation. There are pitfalls; there is considerable variation in the cutaneous innervation of the skin of the hand by the median and by the ulnar nerves and trick movements may mislead. Powerful flexion of the elbow from a strong brachioradialis muscle led to delay in diagnosis of transection of the musculocutaneous nerve for two years in one of our patients. Sympathetic paralysis is a sure sign of degeneration and severe pain indicates substantial nerve injury, scarcely consistent with a diagnosis of non-degenerative conduction block (neurapraxia). Tinel was probably the first to draw attention to the indication of the 'growing point' of the regenerating axons signalled by the production of paraesthesiae by tapping over the course of the nerve? Elicitation of this important clinical feature is simple enough. The examiner lightly percusses along the course of the affected nerve from distal to proximal. When the finger percusses over the zone of regenerating fibres, then the patient will announce the sensation of pins and needles, which may be quite painful, into the cutaneous distribution of that nerve. The following points can be stated: a strongly positive Tinel sign over a lesion soon after injury indicates rupture or severance. It will not be found in a conduction block or non-degenerative lesion. After repair that is going to be successful, the centrifugally moving Tinel sign is persistently stronger than at the suture line. After repair that is going to fail, the Tinel sign at the suture line remains stronger than that at the growing point. Failure of distal progression of the Tinel sign in a closed lesion indicates rupture or other injury not susceptible to recovery by natural process. In closed injuries, from fractures or fracture dislocation, the history of injury is all-important; the extent of force expended upon the nerve trunk can be estimated by velocity and impact or the height of the fall and local bruising or abrasion or linear bruising along the course of a nerve is important evidence of the force expended upon the nerve axis itself. Radiographs are useful in showing the extent of displacement of bone
Table 1
EMG findings in denervation and reinnervation
Denervation
Reinnervation Early Ongoing
Late
Spontaneous activity (fibrillations, positive sharp waves in acute denervation; fasciculations and complex repetitive discharges in chronic denervation) Normal motor units with increased duration because of late potentials (satellite fibres incorporated through collateral sprouting) Moderate amplitude polyphasic motor units of long duration, unstable firing due to variable conduction along unmyelinated sprouts and low safety margin of neuromuscular transmission Large amplitude polyphasic motor units with stable transmission
(From Smith SJM. Electrodiagnosis. In: Seddon HJ (ed) Surgical Disorders of the Peripheral Nerves, pp 467~907, with permission)
fragments and imperfect reduction or blockage of reduction implies interposition of muscle or nerve or artery. Seddon (1975) had the following to say about nerves injured in the arm or at the elbow. 7 He thought that recovery could be awaited if two conditions were met: 'the first is reasonable apposition of bony fragments and the other complete certainty that there is no threat of ischaemia of the forearm muscles'. Seddon further made the important statement when referring to sciatic palsy in fracture of the femoral shaft that 'it is wise always to explore the nerve'. Neurophysiological investigations conveniently fall into two parts. Persisting conduction (sensory action potentials, compound nerve action potentials) excludes a degenerative lesion, confirming the diagnosis of neurapraxia. Conduction ceases altogether within three or four days after severance of the axons. Electromyography assesses the innervation of muscle. At rest, normal muscle is electrically silent and spontaneous activity indicates denervation (Table 1 & 2). Classification of wounds
The single most important determinant of outcome is the violence of injury to the nerve and the limb, and the extent of destruction of nerve tissue is a reflection of this. Rupture or laceration of the major axial artery is a common complication in severe traction injuries, in penetrating missile injuries, and in wounds from knives, and such arterial injury is not rare in fracture dislocation of shoulder and elbow. Rank, Wakefield and Hueston (1973) classified injuries of the hand into 'tidy wounds', amenable to primary repair, and 'untidy wounds' characterized by extensive destruction of tissue and by contamination? This fundamental distinction can be applied to nerve injuries.
The tidy wound In these, caused by knife or glass or the surgeon's scalpel, damage is confined to the wound, and primary repair of all divided structures is desirable. Associated arterial injury is common.
Major nerve injury in the adult upper limb
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Table 2 Electrodiagnostic features of nerve injury Nerve injury type
SAP
Neurapraxia
CMAP
Conduction velocity
EMG
Reduced amplitude proximal to block. Normal amplitude distal to block
Usually preserved
Axonotmesis
.l,
$
Normal/reduced to a degree dependent on severity of axonal degeneration and fibre type involved
Neurotmesis
A
A
Unmeasureable
No/sparse fibrillations Characteristic IP of normal MUPs firing at rapid rates, with reduced interference pattern Fibrillations Reduced IP, $ firing rate of MUPs. Evidence of reinnervation dependent on age of lesion (see Table 1) Profuse fibrillations. No voluntary MUPs.
$, increased; $, decreased; A, absent; CMAP, compound muscle action potential; IP, interference pattern; MUP, motor unit potentiaIs; SAP, sensory action potential From Smith SJM. Electrodiagnosis. In: Seddon HJ (ed) Surgical Disorders of the Peripheral Nerves, pp 467-4907, with permission
Untidy wounds
Level
In these, commonly caused by open fractures or by penetrating missile injury, there is extensive tissue damage, with a high risk of sepsis. Arterial injury is common.
The effect of level of injury is most evident in those nerves of longest course - the median and ulnar. A properly executed urgent repair of either nerve at the wrist will usually result in useful function within the small muscles of the hand, but this is exceptional even in tidy wounds in the axilla. Similarly, repair of the posterior interosseous nerve usually restores extension of fingers and thumb; this is unusual following repair of the radial nerve proximal to the spiral groove. However, urgent repair of stab wounds or even of closed traction ruptures of C5, C6 and C7, or of the upper and middle trunks often achieves results as good as, or even better than, those seen after repair of combined injuries to the suprascapular and circumflex, radial and musculocutaneous nerves in more distal lesions.
The closed traction rupture These injuries are immensely destructive of nerves and of the axial vessels. They are characterized by retraction of the ruptured nerves and vessels and by considerable longitudinal damage within the ruptured trunks. The outcome after nerve repair in this pattern of injury, complicated by arterial lesion, is the worst of all groups. The International Red Cross Wound Classification, set out by Coupland (1993) 9 must be of particular importance to surgeons actively engaged in accident work and particularly so to those dealing with the wounds of war.
Factors in prognosis The MRC Special Report (1954) defined a number of factors which determine outcome after repair of nerves; ~° these were extended by Seddon (1975). 7 Five of these are particularly important: age; level of lesion; the nature of the nerve; the cause of injury; and delay from injury to repair.
Age It is clear that age is very important for those nerves responsible for hand function. A properly performed urgent repair of median and ulnar nerves at the wrist will be followed by function indistinguishable from normal in infancy or young children - a result scarcely seen in adults. However, children are not at all immune from the deleterious effect of delay nor fi'om the depression of regeneration in violent proximal injuries.
The nerve
While there is no such thing as a pure motor or a pure sensory peripheral nerve, it is the case that nerves innervating one or two muscles (the accessory, nerve to serratus anterior, musculocutaneous) fare better than those with extensive territories of cutaneous and muscle innervation such as median, radial and ulnar. However, the ill reputation of the superficial radial and the medial cutaneous of forearm is well deserved. Accidental damage to these, especially to their terminal branches regularly produces severe neuropathic pain states.
Delay The cumulative evidence for harmfulness of delay is overwhelming; the long and wearisome debate about the timing of nerve repairs should be assigned to the dustbin of history. The effects of delay can be considered in general terms: with the passage of every week there is progressive atrophy of target tissues distally and there is also a progressive deterioration of the
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Current Orthopaedics
Table 3 Arterialinjuriesin association with nervelesions
Table 4 Traumatic false aneurysms and arteriovenous fistulae with associated nerve lesions
1975-1996
Vertebral Subclavian Axillary Brachial Radial and ulnar Common femoral Superficial femoral Profunda femoris Inferior gluteal Popliteal Posterior tibial Anterior tibial
Closed
Open
Total Repaired
Total Repaired
1 82 63 7 5 0 2 2 2 14 3 9
0 40 54 6 2 0 2 1 0 9 1 2
4 9 31 35 211 3 4 2 l 12 7 3
1 9 27 31 198 3 4 1 0 9 4 1
Aneurysms
Arteriovenous Fistulae
3 14 4 3 2 1 5 2 1
2 3 1 1 0 0 2 0 0
Region Artery Posterior triangle of neck Axillary Brachial Femoral Profundus femoris Inferior gluteal Popliteal Posterior tibial Anterior tibial
From Surgical Disorders of the Peripheral Nerves,7Ch. 8, with permission)
(From Surgical Disorders of the Peripheral Nerves] Ch. 8, with permission)
c a p a c i t y w i t h i n the central n e r v o u s system for regeneration. L o c a l c h a n g e s include r e t r a c t i o n o f d i v i d e d nerve stumps, f r o m elastic recoil, a n d the progressive fibrosis which ensues w i t h i n t h o s e r u p t u r e d s t u m p s so t h a t the gap b e t w e e n h e a l t h y nerve faces increases. T h e length o f the defect b e t w e e n nerve s t u m p s is a m a t e r i a l f a c t o r in o u t c o m e after repair.
The cause of injury T h e r e are two aspects to this. F i r s t is the extent o f d a m a g e to the nerve a n d loss o f n e u r a l substance. T h e o u t l o o k for a nerve r e p a i r e d after the extensive d e s t r u c t i o n o f a close-range s h o t g u n blast o r an electrical b u r n is far worse t h a n after severance by a knife. S e c o n d is the extent o f injury to the tissues o f the l i m b as a whole. T h o s e o f p a r t i c u l a r significance include d a m a g e to a r t i c u l a r cartilage f r o m i n t r a - a r t i c u l a r fracture o r dislocation, loss o f muscle f r o m burn, i s c h a e m i a o r sepsis, a n d loss o f skin. O f even greater significance t h a n these is the effect o f p e r i p h e r a l ischaemia. It is a cause o f grave c o n c e r n t h a t cases o f o c c l u s i o n o f the b r a c h i a l o r the a x i l l a r y a r t e r y continue to be neglected; it is a l m o s t inconceivable t h a t a c o m p l a c e n t a t t i t u d e is still t a k e n to the t r e a t m e n t o f the pulseless u p p e r limb.
Case study A 23-year-old woman fell downstairs, suffering fracture of the distal humerus. On arrival at the attending hospital, the arm was noted to be pulseless. The fracture was fixed through a posterior approach, the artery itself was not explored and the forearm not decompressed. Twelve hours later, an operation was performed to restore circulation, which failed. The patient was advised to undergo cervical sympathectomy, advice which she declined. She was then referred to St Mary's Hospital, where prompt decompression of the extensor muscles saved them. The flexor muscles of the forearm were necrotic; indeed, they were liquefied and totally excised.
The surgeon faced with this situation might recollect the advice given by earlier workers: Bonney (1963) wrote 'surgeons treating fractures of long bones must be prepared to treat associated vascular injury; ~ London (1967): 'there is nothing so difficult about sewing up an artery as to make it the strict preserve of the vascular specialist'~2 and Birnstingle (1982): 'the ability to repair blood vessels should now be part of the repertory of every accident surgeon'. ~3 Perhaps now is as good a time as any to comment on arterial spasm. We have never seen a case of spasm alone producing obstruction of flow in an adult but we have seen it in children. As to sympathetic block or sympathectomy, Seddon (1964) when writing of acute ischaemia said 'let us hope that the completely futile sympathetic block will not have been done? 4 The final word perhaps should be left to Eastcott in his monumental work Arterial Surgery (1992): 'sympathetic block or denervation are practically useless in the treatment of acute limb ischaemia'. 15 Tables 3 & 4 set out the extent of experience of arterial injuries associated with nerve lesions in two decades. Failure to repair the vessel always induced functional impairment, and in those cases where the subclavian, the axillary or the brachial artery were not repaired, post-ischaemic fibrosis, or worse occurred.
INDICATIONS FOR OPERATION: PRINCIPLES OF NERVE REPAIR This outline o f the principles o f r e p a i r p r e s u p p o s e s t h a t the p a t i e n t ' s general c o n d i t i o n is stable a n d that the s u r g e o n is capable a n d h a s a d e q u a t e facilities. T h e objects o f the i n t e r v e n t i o n include: to to to or
c o n f i r m or establish diagnosis; restore c o n t i n u i t y to a severed o r r u p t u r e d nerve; remove a n o x i o u s agent c o m p r e s s i n g o r d i s t o r t i n g o c c u p y i n g a nerve.
The decision to intervene o n a nerve after injury is never easy, except p e r h a p s in the acute case o f an o p e n w o u n d a n d in cases in which nerve injuries are associated with d a m a g e to m a j o r bones a n d b l o o d vessels. The indications for o p e r a t i o n are p r o b a b l y as follows:
Major nerve injury in the adult upper limb deep paralysis after wounding over the course of a main nerve or injection close to the course of a main nerve; deep paralysis after closed injury, especially highvelocity injury, associated with severe damage to soft tissues, bone or joint; deep paralysis after closed traction injury of the brachial plexus; association of a nerve lesion with evidence of an arterial lesion; association of a nerve lesion with fracture of a related bone requiring early internal fixation; increase in depth of nerve lesion under observation; failure to show evidence of recovery at the expected time after a closed lesion initially thought to be an axonotmesis; failure to show evidence of recovery in conduction block within six weeks of injury; persistent pain almost any interval after injury.
Tidy wounds The ideal course is primary repair of all structures. In most cases, suture of the nerve is possible.
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distal one-third and proximal two-thirds of the forearm and the gap between healthy vascular stumps ranged from 5 12 cm. Vein grafts were used for the radial and ulnar arteries and for three veins. Primary repair of the nerves was done after shortening the limb bones by about 3 cm. Circulation was restored and, by two years, recovery for the median and the ulnar nerves was useful. Experience from this and from three other cases supports reports from those centres with great experience in replantation of the amputated hand or digit which confirm that primary repair of the nerve gives the best result.
Closed traction lesions Traction lesions involving the post-ganglionic elements, the roots and the trunks of the supraclavicular plexus are associated with arterial injury in some 5% of cases. In the severe traction lesion of the infraclavicular brachial plexus there is rupture of the subclavian or axillary artery in 25% of cases, or more, and this arterial injury offers the strongest possible indication for urgent repair. Admittedly, both patient and surgeon may have had enough after an extended operation to deal with the fractures and the arterial lesion.
Untidy wounds The risk is sepsis. Initial aims include restoration of stability of the skeleton, restoration of the circulation and delayed closure of the skin or early recourse to a pedMe or free cutaneous or myocutaneous flap. The latissimus dorsi flap has proved invaluable in the severely damaged upper limb. Nerves will almost always require grafting and timing is a matter of fine judgement. There are situations, from open fracture or ragged laceration from a saw, where primary repair is justified. In other more contaminated cases, it is safer to return to the field at about two weeks. The wounds of industrial or agricultural machinery, of burn or of penetrating missile injury do not permit, as a rule, primary repair. In these cases, replacement of the nerve stumps in their normal anatomical position and tagging or tethering of the stumps with fine monofilament suture is a useful way of minimizing retraction. The replantation of the amputated limb affords the most uncompromising model of this type of injury. Chen et al (1981) reported the results of a co-operative study between Shanghai, Louisville and Zurich in 181 cases? ~ The best results followed replantation of limbs amputated through the distal forearm and wrist, with useful results being obtained in 79%-83% of cases. The worst results were from replantation of the limb amputated or avulsed at shoulder level. Avulsion injuries fared very much worse than did guillotine or crush injuries. The extent of vascular damage is, in itself, no barrier to successful replantation. In one of our cases, a 28-year-old woman threw herself under a train in an attempt at suicide. The dominant hand was amputated at the junction of the
Nerves injured by fracture or dislocations It is important to remember that nerves are injured by damage to the adjacent skeleton by traction from displacement, which commonly ends in rupture, laceration by a fragment of bone, entrapment within the dislocated joint or in a fracture, and late entrapment or compression from callus. On the whole, dislocations are more damaging. It seems to be widely assumed that the prognosis for nerves injured in this way is good but this not generally the case. A surgeon who considers that the fracture requires open reduction and internal fixation will rarely regret exposing the afflicted nerve at the same time; a nerve palsy is an added indication for open reduction and stabilization. Watson Jones (1930) described one of the earliest series on nerve injuries from fractures and dislocations? 7 It remains one of the best. He and Platt (1928) TM were strongly in favour of the exploration of nerves injured by fractures. Seigel and Gelberman (1991) reviewed the subject thoroughly, finding 85% of nerve palsies recovering from closed fractures and 65-70% after open fractures. 19Of those nerves which went on to recovery, 90% had done so by four months. These cannot have been wholly degenerative lesions. Seigel and Gelberman's indications for intervention include the fact that the fracture needs internal fixation, that there is associated vascular injury, that wound exploration of an open fracture is necessary, and that a fracture or dislocation is irreducible. We might add to this two more: the lesion deepens whilst it is under observation; and the lesion occurred during operation for internal fixation of the fracture.
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Current Orthopaedics
Where direct suture of a nerve is not possible, then the mainstay in technique remains autologous grafting. The results of operating on peripheral nerves depend to an extent hardly matched in any other branch of surgery on the skill of the surgeon and the quality of the technique. Nerve suture is done when the gap after resection is small, little mobilization of the nerve is needed to close it and the repaired nerve lies without tension and without excessive flexion of adjacent joints. The experimental work of Clarke et al (1992) clearly showed the ill effect of tension on the repaired nerves. 2° The following principles are useful guides: 1. End-to-end suture of the nerves of the brachial plexus above the clavicle or of the accessory nerve, is nerve practicable. 2. Anterior transposition of the ulnar or radial nerve gives, at most, 3 cm. 3. N o gaps in the median nerve in the forearm can be closed by end-to-end suture. It will be seen that, in m a n y circumstances, it is better to bridge a gap with a graft than to force direct suture; it is better to resect healthy bundles and create a wide gap than to resect too little in order to facilitate direct suture. There are promising developments in techniques other than direct suture or autogenous grafting. Glasby and his colleagues 2~43 have shown that freezethawed muscle grafts are a possible substitute for autogenous graft and T h o m a s and Kitchen 24 clarified a particular role for such grafts in the repair of damaged cutaneous nerves provoking significant pain. M c K i n n o n (1996) describes the use of allografts in a 12-year-old boy with a 20 cm gap in the tibial nerve, which was bridged by 8 allografts? 5 I m m u n o suppression was maintained over four months. M c K i n n o n comments 'in the carefully selected patient with an otherwise irreparable nerve injury, consideration of nerve transplantation should be given'. Lundborg and his colleagues have shown functional recovery, to a high degree, following silicone intubation of divided nerves. 26 In 1997, a significant paper appeared describing a prospective randomized trial comparing silicone intubation and suture of median and ulnar nerves in 18 patients. N o significant difference in the outcome between the two groups was noticed. This is impressive work and, as Professor Lundborg has suggested, the technique offers a potential alternative to nerve grafting in some cases.
slips of the peroneal nerve into slits in the muscle. Reinnervation was secured and the development of end plates in response to the entry of the m o t o r axons was shown. The method works in clinical practice; if the musculocutaneous or other working nerve is reimplanted into the muscle, preferably at the point of avulsion, early after injury, the chances of m o t o r power are high. The use of this technique is rarely required, but it should not be forgotten.
RESULTS Measurement of outcome
Seddon (1975) 7 developed a system for measurement of outcome drawn from the Medical Research Council System, which classed results of nerve repair as good, fair, p o o r and bad (Tables 5 & 6). We have simplified this further into good, fair and poor. For some nerves, muscular function is a good deal more important than recovery of sensation and, for the spinal accessory, suprascapular and circumflex, musculocutaneous and radial nerves, little significance is attached to the extent of recovery of cutaneous sensation except when recovery was complicated by severe pain when the result is considered poor Recovery of sensation has been given equal importance to muscle function in the description o f results o f median and Table 5 Medical Research Council system for grading recoveryin skeletal muscle and in cutaneous sensation
Motor recovery M0 M1 M2 M3
M4 M5
Sensory recovery SO $1 $2
Direct muscular neurotizations
Sometimes, a nerve is avulsed from the muscle that it innervates. The two nerves most commonly afflicted in this way are the circumflex and musculocutaneous. Brunelli and Monini (1985) 27 implanted a working nerve directly into the paralysed muscle. They denervated the sural triceps muscle in rabbits and implanted
No contraction Return of perceptiblecontraction in the proximal muscles Return of perceptiblecontraction in both proximal and distal muscles Return of perceptiblecontraction in both proximal and distal muscles of such degree that all important muscles are sufficientlypowerful to act against resistance Return of function as in Stage 3 with the addition that all synergic and independent movementsare possible Complete recovery
$3+ $4
Absence of sensibilityin the autonomous area Recovery of deep cutaneous pain sensibility within the autonomous area of the nerve Return of some degree of superficialcutaneous pain and tactile sensibilitywithin the autonomous area with disappearance of any previous over-reaction Return of sensibility as in Stage 3 with the addition that there is some recoveryof two-point discrimination within the autonomous area Complete recovery
(From Surgical Disorders of the Peripheral Nerves7Ch. 8, with
permission)
Major nerve injury in the adult upper limb Table 6
Table 7
Gradingof results
Motor recovery
Sensoryrecovery
M4 or better M3 M2 MI & O $4 (normal) or $3+ $3 $2 SI & O
Good Fair Poor Bad Good Fair Poor Bad
(From Surgical Disorders of the PeripheralNerves7Ch. 11, with permission) ulnar nerves; indeed, one could argue that sensibility is the most important function of the median nerve. Some allowance is made for recovery of sympathetic efferent activity in this and in the ulnar nerve. The grade excellent is used rarely, in exceptional cases where function is indistinguishable from the normal. 28 Seddon and his colleagues fully recognized the defects and limitations of the MRC system but it has stood the test of time. Kline and Hudson, in 1995, described a valuable grading system for motor and sensory function and for the whole nerve, which is based on great clinical experience. 29 Constant's shoulder assessment system (1997) is valuable in the analysis of circumflex and suprascapular nerve function. 3° The particular difficulties of measurement of limb function in cases of injury to the adult brachial plexus are addressed by Narakas and in the obstetric brachial plexus palsy by Gilbert and Raimondi and no discussion of these lesions can fail to acknowledge these contributions. (see Surgical Disorders o f the Peripheral Nerves, Ch 9 and 10 for review of these methodsT). For more detailed discussion of methods of measurement, the reader is referred to Bonney, who analyses in considerable detail pitfalls and defects in those systems currently used? 1 The spinal accessory nerve This nerve is usually damaged by surgeons. The lesion is crippling: arguably it is the most significant of all nerve injuries within the upper limb. It is a shameful matter that the nerve is so commonly damaged during operations, that diagnosis is usually delayed, and that only exceptionally are urgent efforts made to rectify the situation. Williams and colleagues made a detailed study of 40 of our cases? 2 As they say, 'injury to the accessory nerve results in a characteristic group of symptoms and signs: reduced shoulder abduction, drooped shoulder and pain. Repair of the nerve reduces symptoms in most cases. Some grasp of the surgical anatomy, together with the use of the nerve stimulator, ought to prevent this serious complication of surgery in the neck'. In Williams' series, delay in diagnosis was usual, ranging from immediate to 32 months and in 26 patients pain was severe even at rest, and disturbed sleep.
15
The spinal accessorynerve (59 repairs)
Excellent Good Fair Poor
6 28 15 10
The nerve tO serratus anterior The nerve is most commonly damaged in lesions of the brachial plexus but it is particularly vulnerable for accidental damage where it crosses the first and second rib. When serratus anterior is paralysed, the inferior pole of the scapula does not move forward but slides medially and cranially. Confusion with spinal accessory palsy is a common error. Deep aching pain is common, and sometimes severe. When we have been given the chance to repair the nerve after a stab wound (5 cases) or intra-operatively (6 cases) results have been very good, even better than for almost any other peripheral nerve. Circumflex and suprascapular nerves It is our experience that U K orthopaedic surgeons tend to adopt an expectant approach to circumflex palsy, unlike their more energetic approach to other injuries of peripheral nerves, notably to the brachial plexus. We think that Nunley and GabeP 3 are right when they say, 'if no evidence of clinical or electromyographic recovery is seen at two or three months after injury, exploration should be performed ... recovery is unlikely after twelve months of denervation, and surgical treatment is of negligible benefit in this setting'. Ochiai and his colleagues 34presented very significant work describing the treatment of combined injuries of the circumflex and suprascapular nerves and they showed that the suprascapular nerve might be severely damaged at several places. They recommended that this nerve should be exposed along its entire course as far as infraspinatus and the recommended exposure is described in detail in this valuable paper. Spilsbury and Birch 35 reported findings in 129 nerve injuries in 98 patients (Tables 8 & 9). Spilsbury's myometric Studies suggested that the deltoid muscle was responsible for over 50% of the power of abduction, about 30% of forward flexion power and 80% of extension power at the shoulder. Improvement in strength and in stamina was not impressive even in those cases where the outcome was considered good. Results are bad with associated rupture of the rotator cuff, even in three cases when the cuff was repaired at the same time as grafting the circumflex nerve. Intraarticular fracture provoked post-traumatic arthritis in three more cases. Tight contracture of the capsule was a common contributory factor to iailure, especially after multiple ruptures of nerve trunks. All repairs of the circumflex nerve performed at more than one year from injury failed.
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Current Orthopaedics Table 8 Circumflex and suprascapular nerves: grading of results Circumflex: Good Fair Poor or bad
Deltoid Deltoid Deltoid
Suprascapular: Good Fair Poor
Abduction 120° or more Abduction 90-120 ° Less
MRC 4 or better MRC 3+ or better Less
Abduction Abduction Less
Elevation at least 120° Elevation 90-120 °
Later rotation 3° or more Lateral rotation 0 30° Less
From Surgical Disorders of the Peripheral Nerves 7, Ch. 11, with permission)
This is one o f the best nerves to repair, so m u c h so t h a t r e p a i r was a t t e m p t e d even in extremely u n f a v o u r a b l e cases w i t h p o s t - i s c h a e m i c fibrosis, after direct d a m a g e to the e l b o w flexor muscles, o r after p r o l o n g e d delay. T h r e e sutures failed a n d these were revised with grafts achieving two g o o d a n d one fair result (Table 10).
extension o f the e l b o w ( M R C 4) followed repair. A s one m i g h t expect, recovery for the p o s t e r i o r interosseous nerve is usually g o o d . Shergill a n d colleagues 36 f u r t h e r s t u d i e d the o u t c o m e o f 260 repairs o f the r a d i a l a n d p o s t e r i o r i n t e r o s s e o u s nerves. Overall, there were 30% o f g o o d results, a n d 28% fair f r o m the 242 r a d i a l nerve repairs. T h e m o s t i m p o r t a n t f a c t o r in the p r o g n o s i s was s h o w n to be the violence o f the injury. Seventy-nine p e r cent o f the o p e n ' t i d y ' repairs achieved a g o o d o r fair result c o m p a r e d to 36% o f cases where there was a s s o c i a t e d arterial injury. T h e r e were very few w o r t h w h i l e results f r o m r e p a i r in which the defect o f the nerve t r u n k exceed 10 cm. D e l a y was i m p o r t a n t , Sixty-five p e r cent o f 38 repairs in the o p e n ' t i d y ' g r o u p p e r f o r m e d within 14 days o f the injury were c o n s i d e r e d good. N o useful results were seen w h e n the interval b e t w e e n injury a n d r e p a i r exceeded twelve m o n t h s . Sixteen o f 18 repairs o f the p o s t e r i o r interosseous nerve achieved a g o o d result.
The radial nerve (Tables 11 & 12)
The median and ulnar nerves
These results are n o t as g o o d as one m i g h t expect; t h e y a p p e a r to be inferior to t h o s e r e p o r t e d b y S e d d o n . 7 U s e f u l wrist extension was r e g a i n e d in twothirds o f patients b u t extension o f the finger a n d the t h u m b in only one-third. I n h i g h lesions o f the p o s t e r i o r cord, the result was g r a d e d as fair if useful
T h e effect o f age a n d o f level o f i n j u r y are p a r t i c u l a r l y evident for these two nerves. Equally, o r even m o r e so, is the effect o f the cause o f i n j u r y a n d the delay b e t w e e n injury a n d repair. C l e a r evidence o f this c o m e s f r o m the study b y C a v a n a g h et aP 7 o f the c o m p l e x infraclavicular i n j u r y in which several nerve
Table 9 Outcome in repairs of the circumflex and suprascapular nerves Circumflex nerve (56 repairs) Good Fair 25 23
Poor 8
Suprascapular nerve (24 repairs): Good Fair 20 2
Poor 2
(From Surgical Disorders of the Peripheral Nerves 7, Ch. 11, with permission)
The musculocutaneous nerve
Table 10 Results of 154 repairs of musculocutaneous nerves (children and adults)
Good Fair Poor Totals
Tidy
Untidy (incl. penetrating missile injuries)
Traction
Total
21 3 1 25
26 8 6 40
55 24 10 89
102 35 17 154
Good: Flexion of elbow. M4 or better; Fair: Flexion of elbow against gravity; Poor:
Good Fair Poor Totals
Tidy
Untidy (inc. penetrating missile wounds)
Traction
Total
12 10 5 27
20 18 16 54
6 19 25 50
38 47 46 131
Good: Extension of elbow, wrist and digits. MRC 4 or better; Fair: Extension of elbow and wrist against gravity; Poor: < M3. (From Surgical Disorders of the Peripheral Nerves 7, Ch. 11, with permission)
M a j o r nerve i n j u r y in the a d u l t u p p e r limb
Table 12 Posterior interosseous nerve (11 cases)
Table 13 Resultsfor nerves injured
Good 8
injured nerves
Fair 2
Poor 1
Good: active extension of fingers and thumb. MRC 4 or better; Fair: active extension of fingers and thumb. MRC 3 or 3+; Poor: less than the above. (From Surgical Disorders of the Peripheral Nerves7, Ch. 11, with permission)
Table 14
Good
Fair
Poor
Total
Median and ulnar Radial and musculocutaneous Suprascapular and circumflex
15 29 12
21 20 3
19 8 3
55 57 18
Totals
56
44
30
130
From Surgical Disorders of the Peripheral Nerves7, Ch. 11, with permission)
Resultsby cause
Lesion
Good
Fair Poor Total
Closed Infraclavicular with supraclavicular involvement Infraclavicular only
1
4
6
11
31
30
19
80
Open
24
10
5
39
Totals
56
44
30
130
(From Surgical Disorders of the Peripheral Nerves7, Ch. 11, with permission)
Table 15 Resultsrelated to interval between injury and repair Lesion
17
Good
Fair
Poor
Total
Table 16 Grading of results in high median and ulnar nerve repair Median Long flexor muscles MRC 4 or better Localization to digit, without hypersensitivity Return of sweating Fair Long flexormuscles MRC 3 or 3+ 'Protective sensation'. Moderate or no hypersensitivity Sweating diminished or absent Poororbad Long flexor muscles MRC 2 or less 'Protective sensation' but severe hypersensitivityor no sensation Good
Ulnar Good
Early: within 14 days Median and ulnar Radial and musculocutaneous Suprascapular and circumflex
14 19 7
13 i0 2
6 1 2
33 30 11
Totals
40
25
9
74
Late: after 14 days (22 weeks on average) Median and ulnar Radial and musculocutaneous Suprascapular and circumflex
1 10 5
8 l0 1
13 7 1
22 27 7
Totals
I6
i9
2I
56
FCU and FDP little and ring MRC 4 or better Intrinsic muscles MRC 2 or better Localization to little and ring fingers. No hypersensitivity. Return of sweating Fair FCU and FDP little and ring fingers MRC 3 or 3+ No intrinsic muscle function 'Protective' sensation little and ring fingers Moderate hypersensitivity Little or no sweating Poor or bad FCU and FDP little and ring fingers MRC 2 No intrinsic muscle function 'Protective' sensation with severe hypersensitivityor no sensation No sweating
(From Surgical Disorders of the Peripheral Nerves7, Ch. 11, with permission)
(From Surgical Disorders of the Peripheral Nerves7, Ch. 11, with permission)
t r u n k s were r u p t u r e d or t o r n by knife or missile, a n i n j u r y complicated by r u p t u r e o f the axillary artery in over o n e - t h i r d o f cases. Results for the i n j u r e d nerve, by cause, a n d by the interval between i n j u r y a n d repair, are set o u t in Table 13 15. The results after repair o f a high m e d i a n a n d u l n a r nerve lesion are, o n the whole, m u c h m o r e m o d e s t t h a n those following m o r e distal repairs, a n d thus a less d e m a n d i n g system o f assessment is used for repairs of these nerves d a m a g e d i n the axilla a n d a r m (Table 16). Results are described in Tables 17 a n d 18.
CONCLUSION
Distal lesions Results for m e d i a n a n d u l n a r nerves in the forearm a n d wrist were presented by Birch a n d Raji; 28 the m e t h o d o f assessment used in that series is set out in Table 19 a n d the results for 254 nerves are set out i n Tables 20 a n d 21.
T h e evidence shows that of all the factors relating to the o u t c o m e o f nerve repair delay is the m o s t significant o f those within the control o f the surgeon, b u t this counsel o f perfection must be tempered by the practical problems facing the surgeon called u p o n to treat patients with severe injuries. Stabilization of the skeleton, restoration o f circulation, a d e q u a t e t r e a t m e n t of the w o u n d a n d recognition o f the nerve lesion are admirable aims. N o great h a r m comes from d o i n g what is necessary before r e t u r n i n g later to the nerve itself, or perhaps referring the p a t i e n t to a n interested colleague. Diagnosis is (nearly) all. This particularly applies to the serious p r o b l e m o f nerves i n j u r e d during operation, which seems to be increasing. The difficulties facing surgeons in these circumstances are m a d e m o r e by changes in terms o f e m p l o y m e n t a n d by early recourse to so-called 'disciplinary' procedures
18 Current Orthopaedics Table 17
Results in 85 repairs of median nerves in axilla or arm (adults and children)
Good Fair Poor or bad Total
Tidy
Untidy (incl. penetrating missile injuries)
Traction
Total
6 8 3 17
4 8 12 24
3 15 26 44
13 31 41 85
a This includes 28 repairs of either lateral or medial root of the nerve in the axilla. (From Surgical Disorders of the Peripheral Nerves7, Ch. 11, with permission)
Table 18
Results of 60 repairs of medial cord or ulnar nerve in axilla and arm (children and adults)
Good ° Fair Poor or bad b TOTAL
Tidy
Untidy (incl. penetrating missile injuries)
Traction
Total
3 5 2 10
2 13 10 25
0 7 18 25
5 25 30 60
"All 5 good results followed repair within 48 hours of injury - 2 in children; b Results of repair after 3 months of injury were always poor in the untidy and traction lesions. (From Surgical Disorders of the Peripheral Nerves7, Ch. 11, with permission)
Table 19
Methods of grading results of median and ulnar nerves
Grade
Motor
Sensory
Equivalent on Seddon's grading
Excellent
Power MRC 5 No wasting or deformity No trophic changes Power MRC 4 to 5. Abolition of paralytic deformity Minimal pulp wasting MRC 3 or more. Some sweating. Pulp wasted
Function indistinguishable from normal hand. Good stereognosis, no hypersensitivity. 2PD" equivalent to uninjured digits Accurate speedy localization. Can recognize texture or objects. Minor cold sensitivity and hypersensitivity. 2PD < 8 mm at tips of fingers Accurate localization to digit. No stereognosis. 2PD > 8 mm. Significant cold sensitivity and hypersensitivity No sensation or severe cold sensitivity and hypersensitivity
Good M5, $4
Good
Fair
Poor and bad
MRC 3 or less. No sweating, Trophic changes
Good M5, $3+
Fair. M3, $3
Bad M 01 or 2S 01 or2
"Two-pointdiscrimination (From Surgical Disorders of the Peripheral Nerves7, Ch. 11, with permission)
Table 20 Repair of 119 median nerves in adults (16-65 years) in tidy wounds from distal wrist crease to elbow crease Primary repair
Delayed suture
Graft
Total
Excellent Good Fair Poor or bad
5 27 12 2
1 9 14 7
0 12 25 5
6 48 51 14
TOTAL
46
31
42
(From Surgical Disorders of the Peripheral Nerves7, Ch. 11, wi~/h permission)
Table 21 Repair 145 ulnar nerves in adults (16-65 years) in tidy wounds from distal wrist crease to elbow crease Primary repair
Delayed suture
Graft
Total
Excellent Good Fair Poor or bad
8 25 13 0
1 6 16 9
2 22 27 16
11 53 56 25
TOTAL
46
32
67
145
(From Surgical Disorders of the Peripheral Nerves7, Ch. 11, with permission)
M a j o r n e r v e i n j u r y in the a d u l t u p p e r l i m b
by T r u s t s o r others. T h i s g r a v e issue is d e b a t e d in c o n s i d e r a b l e d e p t h by B o n n e y ¢ 8 r e a d e r s are u r g e d to s t u d y this. REFERENCES
1. Waller A. Experiments on the section of the glossopharyngeal and hypoglossal nerves of the frog, and observations of the alterations produced thereby in the structure of their primitive fibres. Philosophical Transactions of the Royal Society of London 1850; 140: 423429. 2. Bonney G. Reactions to injury. In: Birch R, Bonney G, Wynn Parry C (eds) Surgical Disorders of the Peripheral Nerves. Edinburgh: Churchill Livingstone, 1998: 40, Ch. 4. 3. Dyek PJ, Nukada H, Lais CA, Karnes J. Permanent axotomy: a model of chronic neuronal degeneration produced by axonal atrophy, myelin remodelling and regeneration. In: Dyck PJ, Thomas PK, Lambert EH, Bunge R (eds) Peripheral Neuropathy, 2nd edn. Philadelphia: WB Saunders, 1984: 660-690. 4. Seddon HJ. Three types of nerve injury. Brain 1943; 66: 237-288. 5. Bonney G. Reactions to Injury. In: Birch R, Bonney G, Wynn Parry C (eds) Surgical Disorders of the Peripheral Nerves. Edinburgh: Churchill Livingstone, 1998:41, Ch. 4. 6. Tinel J. Nerve Wounds. London: Baillibre Tindall and Cox, 1917: 73. 7. Seddon HJ. Surgical Disorders of the Peripheral Nerves. Edinburgh: Churchill Livingstone, 1975. 8. Rank BK, Wakefield AR, Hueston JT. Surgery of Repair as Applied to Hand Injuries. Edinburgh: Churchill Livingstone, 1973. 9. Coupland RM. War Wounds of Limbs. Oxford: Butterworth Heinemann, 1993. 10. Medical Research Council Special Report Series No. 282. 1954. Peripheral Nerve Injuries. Ed: Seddon HJ. London: HMSO, 1954. 11. Bonney G. Thrombosis of the femoral artery complicating fracture of the femur. J Bone Joint Surg 47B: 288-272. 12. London PS. A Practical Guide To The Care Of The Injured. Edinburgh: E & S Livingstone, 1967: 664. 13. Birnstingl M. Vascular Injuries. In: Watson-Jones R (ed) Fractures and Joint Injuries. 6th edn. Edinburgh: Churchill Livingstone, 1982:211-241. 14. Seddon HJ. Volkmann's ischaemia. Br Med J 1964; 1: 1587. 15. Eastcott HHG, Blaisdell FW, Silver D. In: Eastcott HHG (ed) Arterial Surgery, 3rd edn. Edinburgh: Churchill Livingstone, 1992: 31-54. 16. Chen ZW, Meyer VE, Kleinert HE, Beasley RW Present indications and contraindications for replantation as reflected by long-term functional results. Orthop Clin N Am 1981: 849-870. 17. Watson-Jones R. Primary nerve lesions in injuries of the elbow and wrist. Bone Joint Surg 1930; 12: 121-140. 18. Platt H. Ext. popliteal nerve involvement in fractures of fibula. J Bone Joint Surg 1928; I0: 42. 19. Siegel DB, Gelberman RG. Peripheral neve injuries associated with fractures and dislocations In: Gelberman R H (ed)
20. 21. 22. 23. 24. 25. 26.
27.
28. 29. 30. 31.
32. 33. 34.
35. 36. 37. 38.
19
Operative Nerve Repair and Reconstruction. Philadelphia: JB Lippincott, 1991: 619-633. Clark WL, Trumble TE, Swiontowski MF, Tencer AF. Nerve tension and blood flow in a model of immediate and delayed repairs. J Hand Surg 1992; 17A: 677-687. Gattuso JM, Davies AH, Glasby MA, Gschmeissner SE, Huang CLH. Peripheral nerve repair using muscle autografts. J Bone Joint Surg 1988; 70B: 524-529. Glasby MA. Nerve growth in matrices of orientated muscle basement membrane. Developing a new method of nerve repair. Clin Anat 1990; 3: 161-182. Hems TEL Glasby MA. The limit in graft length in the experimental use of muscle grafts for nerve repair. J Hand Surg 1993; 18B: 165-170. Thomas DGT, Kitchen ND. Long term follow up of dorsal root entry zone lesions in brachial plexus avulsion. J Neurol Neurosurg Psychiatry 1994; 57: 737-738. Mackinnon SE. Nerve allotransplantation following severe tibia1 nerve injury. J Neurosurg 1996; 84: 671-676. Lundborg G, Rosen B, Dahlin L, Danielsen N, Holmberg J. Tubular versus conventional repair of median and ulnar nerves in the human Ibrearm: early results from a prospective, randomised clinical study. J Hand Surg 1997; 22A: 99-106. Brunelli G, Monini L. Direct muscular neurotisation. Proceedings of the Second Congress of the International Federation of Societies for Surgery of the Hand. J Hand Surg 1985; 10A: 993-994. Birch R, Raji ARM. Repair of median and ulnar nerves. J Bone Joint Surg 1991; 73B: 154-157. Kline DG, Hudson AR (eds) Grading results. In: Nerve Injuries. Philadelphia: WB Saunders, 1995: 87-99. Constant CR. Assessment of shoulder function In: Copeland S (ed) Shoulder Surgery. Philadelphia: WB Saunders, 1997. Bonney G. Clinical aspects of nerve injury. In: Birch R, Bonney G, Wynn Parry C (eds) Surgical Disorders of the Peripheral Nerves. Edinburgh: Churchill Livingstone, 1998; 71-86, Ch. 6. Williams WW, Twyman RS, Donell ST. The posterior triangle and the painful shoulder: spinal accessory nerve injury. Ann R Coll Surg 1996; 78: 521-525. Nunley JA, Gabel G. Axillary nerve. In: Gelberman RH (ed) Operative Nerve Repair and Reconstruction. Philadelphia: JB Lippincott, 1991: 437~452. Ochiai N, Nagano A, Akinaga S, Murashima R, Tachibana S. Braehial plexus injuries: surgical treatment of combined injuries of the axillary and suprascapular nerves J Jap Soc Surg Hand 1988; 5: 151-155. Spilsbury L Birch R. Some lesions of the circumflex and suprascapular nerves (abstract). J Bone Joint Surg 1996; 73B: Suppl. 1:59. Shergill G, Birch R, Luo Z J, Dega RK. Prognostic factors for recovery following repair of radial nerve injuries J Bone Joint Surg Suppl. 1 1998; Vol 80B: 59. Cavar~agh SP, Birch R, Bonney G. The infraclavicular brachial plexus: the case for primary repair. J Bone Joint Surg (Br) 1987; 69:489 (abstract). Bonney G. Iatropathic injury. In: Birch R, Bonney G, Wynn Parry C (eds) Surgical Disorders of the Peripheral Nerves. Edinburgh: Churchill Livingstone, 1998: 293-334, Ch. 13.
Mini-symposium: Surgical neurology of the upper limb
(ii) The treatment and prognosis of major nerve injury in the adult upper limb
R. Birch INTRODUCTION Precision in diagnosis is the first and essential step in the treatment of any disease or injury and lesions of the peripheral nerves offer the astute clinician an unequalled opportunity to arrive at precise diagnosis on the basis of the history and simple but accurate physical examination with only occasional reference to specific ancillary investigations. This presupposes knowledge of elementary anatomical and physiological principles: perhaps a dangerous assumption! This paper briefly summarizes some aspects of injury of those nerves derived from the anterior primary rami of the fifth, sixth, seventh and eighth cervical and first thoracic spinal nerves and also to the eleventh cranial nerve (the spinal accessory nerve).
DIAGNOSIS
The distinction which must be made lies between the degenerative and non-degenerative lesion. When an axon is cut, changes first described by Waller (1850), ~ and now known as Wallerian degeneration, follow. Distal to the lesion, the axon degenerates and conduction is lost at about three to four days. All function is lost. A particularly important clinical sign of this is the vaso- and sudomotor paralysis from interruption of the post-ganglionic sympathetic fibres. The skin in the territory o f the affected nerve becomes red and dry. There are progressive changes in the target organs, in muscle, skin, blood vessels and the sensory organelles which become irreversible. Muscle denervated for two years or more is lost to function. Of
Rolfe Birch MChir FRCS, The Royal National Orthopaedic
Hospital Trust, BrockleyHill, Stanmore,MiddlesexHA7 4LP, UK
equal significance, however, are the changes which occur proximally after transection of the axon. The proximal portion narrows and, in the parent neurone, there is chromatolysis and retraction of dendrites. 'These processes may continue to actual dissolution of the cell body'. 2 Dyck et al (1984) were able to study the effect of permanent axonotomy in the spinal cord of two patients years after amputation of a lower limb? They found that 'loss of target tissue by axotomy leads to atrophy and then loss of motor neurones'. These central changes are more extreme in more proximal, more extensive and more violent injuries. They are a fundamental factor in prognosis after repair and one important explanation for the harmfulness of delay of nerve repair after such lesions. A classification of nerve injuries introduced by Seddon distinguished between three types of injuries? • neurapraxia (nerve not working) implies a physiological block to conduction but no anatomical disturbance of the nerve; • axonotmesis (axon cutting) in which the axon is severed, its distal portion degenerates, but the basal lamina of the Schwann cell remains intact; • neurotmesis (nerve cutting) describes the lesion where there is interruption of continuity of all elements of the nerve. In neurapraxia, distal conduction persists, the axon has not been cut and it does not degenerate. On the other hand, Wallerian degeneration occurs in both axonotmesis and neurotmesis. Here we have two lesions in which the prognosis is favourable - neurapraxia and axonotmesis - if the cause is removed, and one further lesion - neurotmesis, in which recovery can occur only if the nerve is repaired. We should remember that a favourable lesion may deepen to one much less favourable if the original cause is not dealt
10
Current Orthopaedics
with. Recovery is likely for a nerve accidentally encircled by a suture or crushed under a plate if the cause is urgently removed. If the offending cause remains for days or weeks, then a much more unfavourable lesion develops. Nerves crushed in the swollen ischaemic limb or in a tense compartment progress from conduction block to much deeper and much less favourable degenerative lesions. As Bonney stated, 'we on the contrary have tended towards a further simplification: to classification as "degenerative" and "non-degenerative". This, we think, is the manner in which clinicians should regard a nerve injury the first question to be asked is: is this lesion degenerative or non-degenerative'? When a nerve has stopped working and there is a wound over the course of a nerve, then the diagnosis is nerve transection until proven otherwise. The extent of lesion is shown by weakness or paralysis of muscle and by the extent of loss of cutaneous sensation. There are pitfalls; there is considerable variation in the cutaneous innervation of the skin of the hand by the median and by the ulnar nerves and trick movements may mislead. Powerful flexion of the elbow from a strong brachioradialis muscle led to delay in diagnosis of transection of the musculocutaneous nerve for two years in one of our patients. Sympathetic paralysis is a sure sign of degeneration and severe pain indicates substantial nerve injury, scarcely consistent with a diagnosis of non-degenerative conduction block (neurapraxia). Tinel was probably the first to draw attention to the indication of the 'growing point' of the regenerating axons signalled by the production of paraesthesiae by tapping over the course of the nerve? Elicitation of this important clinical feature is simple enough. The examiner lightly percusses along the course of the affected nerve from distal to proximal. When the finger percusses over the zone of regenerating fibres, then the patient will announce the sensation of pins and needles, which may be quite painful, into the cutaneous distribution of that nerve. The following points can be stated: a strongly positive Tinel sign over a lesion soon after injury indicates rupture or severance. It will not be found in a conduction block or non-degenerative lesion. After repair that is going to be successful, the centrifugally moving Tinel sign is persistently stronger than at the suture line. After repair that is going to fail, the Tinel sign at the suture line remains stronger than that at the growing point. Failure of distal progression of the Tinel sign in a closed lesion indicates rupture or other injury not susceptible to recovery by natural process. In closed injuries, from fractures or fracture dislocation, the history of injury is all-important; the extent of force expended upon the nerve trunk can be estimated by velocity and impact or the height of the fall and local bruising or abrasion or linear bruising along the course of a nerve is important evidence of the force expended upon the nerve axis itself. Radiographs are useful in showing the extent of displacement of bone
Table 1
EMG findings in denervation and reinnervation
Denervation
Reinnervation Early Ongoing
Late
Spontaneous activity (fibrillations, positive sharp waves in acute denervation; fasciculations and complex repetitive discharges in chronic denervation) Normal motor units with increased duration because of late potentials (satellite fibres incorporated through collateral sprouting) Moderate amplitude polyphasic motor units of long duration, unstable firing due to variable conduction along unmyelinated sprouts and low safety margin of neuromuscular transmission Large amplitude polyphasic motor units with stable transmission
(From Smith SJM. Electrodiagnosis. In: Seddon HJ (ed) Surgical Disorders of the Peripheral Nerves, pp 467~907, with permission)
fragments and imperfect reduction or blockage of reduction implies interposition of muscle or nerve or artery. Seddon (1975) had the following to say about nerves injured in the arm or at the elbow. 7 He thought that recovery could be awaited if two conditions were met: 'the first is reasonable apposition of bony fragments and the other complete certainty that there is no threat of ischaemia of the forearm muscles'. Seddon further made the important statement when referring to sciatic palsy in fracture of the femoral shaft that 'it is wise always to explore the nerve'. Neurophysiological investigations conveniently fall into two parts. Persisting conduction (sensory action potentials, compound nerve action potentials) excludes a degenerative lesion, confirming the diagnosis of neurapraxia. Conduction ceases altogether within three or four days after severance of the axons. Electromyography assesses the innervation of muscle. At rest, normal muscle is electrically silent and spontaneous activity indicates denervation (Table 1 & 2). Classification of wounds
The single most important determinant of outcome is the violence of injury to the nerve and the limb, and the extent of destruction of nerve tissue is a reflection of this. Rupture or laceration of the major axial artery is a common complication in severe traction injuries, in penetrating missile injuries, and in wounds from knives, and such arterial injury is not rare in fracture dislocation of shoulder and elbow. Rank, Wakefield and Hueston (1973) classified injuries of the hand into 'tidy wounds', amenable to primary repair, and 'untidy wounds' characterized by extensive destruction of tissue and by contamination? This fundamental distinction can be applied to nerve injuries.
The tidy wound In these, caused by knife or glass or the surgeon's scalpel, damage is confined to the wound, and primary repair of all divided structures is desirable. Associated arterial injury is common.
Major nerve injury in the adult upper limb
11
Table 2 Electrodiagnostic features of nerve injury Nerve injury type
SAP
Neurapraxia
CMAP
Conduction velocity
EMG
Reduced amplitude proximal to block. Normal amplitude distal to block
Usually preserved
Axonotmesis
.l,
$
Normal/reduced to a degree dependent on severity of axonal degeneration and fibre type involved
Neurotmesis
A
A
Unmeasureable
No/sparse fibrillations Characteristic IP of normal MUPs firing at rapid rates, with reduced interference pattern Fibrillations Reduced IP, $ firing rate of MUPs. Evidence of reinnervation dependent on age of lesion (see Table 1) Profuse fibrillations. No voluntary MUPs.
$, increased; $, decreased; A, absent; CMAP, compound muscle action potential; IP, interference pattern; MUP, motor unit potentiaIs; SAP, sensory action potential From Smith SJM. Electrodiagnosis. In: Seddon HJ (ed) Surgical Disorders of the Peripheral Nerves, pp 467-4907, with permission
Untidy wounds
Level
In these, commonly caused by open fractures or by penetrating missile injury, there is extensive tissue damage, with a high risk of sepsis. Arterial injury is common.
The effect of level of injury is most evident in those nerves of longest course - the median and ulnar. A properly executed urgent repair of either nerve at the wrist will usually result in useful function within the small muscles of the hand, but this is exceptional even in tidy wounds in the axilla. Similarly, repair of the posterior interosseous nerve usually restores extension of fingers and thumb; this is unusual following repair of the radial nerve proximal to the spiral groove. However, urgent repair of stab wounds or even of closed traction ruptures of C5, C6 and C7, or of the upper and middle trunks often achieves results as good as, or even better than, those seen after repair of combined injuries to the suprascapular and circumflex, radial and musculocutaneous nerves in more distal lesions.
The closed traction rupture These injuries are immensely destructive of nerves and of the axial vessels. They are characterized by retraction of the ruptured nerves and vessels and by considerable longitudinal damage within the ruptured trunks. The outcome after nerve repair in this pattern of injury, complicated by arterial lesion, is the worst of all groups. The International Red Cross Wound Classification, set out by Coupland (1993) 9 must be of particular importance to surgeons actively engaged in accident work and particularly so to those dealing with the wounds of war.
Factors in prognosis The MRC Special Report (1954) defined a number of factors which determine outcome after repair of nerves; ~° these were extended by Seddon (1975). 7 Five of these are particularly important: age; level of lesion; the nature of the nerve; the cause of injury; and delay from injury to repair.
Age It is clear that age is very important for those nerves responsible for hand function. A properly performed urgent repair of median and ulnar nerves at the wrist will be followed by function indistinguishable from normal in infancy or young children - a result scarcely seen in adults. However, children are not at all immune from the deleterious effect of delay nor fi'om the depression of regeneration in violent proximal injuries.
The nerve
While there is no such thing as a pure motor or a pure sensory peripheral nerve, it is the case that nerves innervating one or two muscles (the accessory, nerve to serratus anterior, musculocutaneous) fare better than those with extensive territories of cutaneous and muscle innervation such as median, radial and ulnar. However, the ill reputation of the superficial radial and the medial cutaneous of forearm is well deserved. Accidental damage to these, especially to their terminal branches regularly produces severe neuropathic pain states.
Delay The cumulative evidence for harmfulness of delay is overwhelming; the long and wearisome debate about the timing of nerve repairs should be assigned to the dustbin of history. The effects of delay can be considered in general terms: with the passage of every week there is progressive atrophy of target tissues distally and there is also a progressive deterioration of the
12
Current Orthopaedics
Table 3 Arterialinjuriesin association with nervelesions
Table 4 Traumatic false aneurysms and arteriovenous fistulae with associated nerve lesions
1975-1996
Vertebral Subclavian Axillary Brachial Radial and ulnar Common femoral Superficial femoral Profunda femoris Inferior gluteal Popliteal Posterior tibial Anterior tibial
Closed
Open
Total Repaired
Total Repaired
1 82 63 7 5 0 2 2 2 14 3 9
0 40 54 6 2 0 2 1 0 9 1 2
4 9 31 35 211 3 4 2 l 12 7 3
1 9 27 31 198 3 4 1 0 9 4 1
Aneurysms
Arteriovenous Fistulae
3 14 4 3 2 1 5 2 1
2 3 1 1 0 0 2 0 0
Region Artery Posterior triangle of neck Axillary Brachial Femoral Profundus femoris Inferior gluteal Popliteal Posterior tibial Anterior tibial
From Surgical Disorders of the Peripheral Nerves,7Ch. 8, with permission)
(From Surgical Disorders of the Peripheral Nerves] Ch. 8, with permission)
c a p a c i t y w i t h i n the central n e r v o u s system for regeneration. L o c a l c h a n g e s include r e t r a c t i o n o f d i v i d e d nerve stumps, f r o m elastic recoil, a n d the progressive fibrosis which ensues w i t h i n t h o s e r u p t u r e d s t u m p s so t h a t the gap b e t w e e n h e a l t h y nerve faces increases. T h e length o f the defect b e t w e e n nerve s t u m p s is a m a t e r i a l f a c t o r in o u t c o m e after repair.
The cause of injury T h e r e are two aspects to this. F i r s t is the extent o f d a m a g e to the nerve a n d loss o f n e u r a l substance. T h e o u t l o o k for a nerve r e p a i r e d after the extensive d e s t r u c t i o n o f a close-range s h o t g u n blast o r an electrical b u r n is far worse t h a n after severance by a knife. S e c o n d is the extent o f injury to the tissues o f the l i m b as a whole. T h o s e o f p a r t i c u l a r significance include d a m a g e to a r t i c u l a r cartilage f r o m i n t r a - a r t i c u l a r fracture o r dislocation, loss o f muscle f r o m burn, i s c h a e m i a o r sepsis, a n d loss o f skin. O f even greater significance t h a n these is the effect o f p e r i p h e r a l ischaemia. It is a cause o f grave c o n c e r n t h a t cases o f o c c l u s i o n o f the b r a c h i a l o r the a x i l l a r y a r t e r y continue to be neglected; it is a l m o s t inconceivable t h a t a c o m p l a c e n t a t t i t u d e is still t a k e n to the t r e a t m e n t o f the pulseless u p p e r limb.
Case study A 23-year-old woman fell downstairs, suffering fracture of the distal humerus. On arrival at the attending hospital, the arm was noted to be pulseless. The fracture was fixed through a posterior approach, the artery itself was not explored and the forearm not decompressed. Twelve hours later, an operation was performed to restore circulation, which failed. The patient was advised to undergo cervical sympathectomy, advice which she declined. She was then referred to St Mary's Hospital, where prompt decompression of the extensor muscles saved them. The flexor muscles of the forearm were necrotic; indeed, they were liquefied and totally excised.
The surgeon faced with this situation might recollect the advice given by earlier workers: Bonney (1963) wrote 'surgeons treating fractures of long bones must be prepared to treat associated vascular injury; ~ London (1967): 'there is nothing so difficult about sewing up an artery as to make it the strict preserve of the vascular specialist'~2 and Birnstingle (1982): 'the ability to repair blood vessels should now be part of the repertory of every accident surgeon'. ~3 Perhaps now is as good a time as any to comment on arterial spasm. We have never seen a case of spasm alone producing obstruction of flow in an adult but we have seen it in children. As to sympathetic block or sympathectomy, Seddon (1964) when writing of acute ischaemia said 'let us hope that the completely futile sympathetic block will not have been done? 4 The final word perhaps should be left to Eastcott in his monumental work Arterial Surgery (1992): 'sympathetic block or denervation are practically useless in the treatment of acute limb ischaemia'. 15 Tables 3 & 4 set out the extent of experience of arterial injuries associated with nerve lesions in two decades. Failure to repair the vessel always induced functional impairment, and in those cases where the subclavian, the axillary or the brachial artery were not repaired, post-ischaemic fibrosis, or worse occurred.
INDICATIONS FOR OPERATION: PRINCIPLES OF NERVE REPAIR This outline o f the principles o f r e p a i r p r e s u p p o s e s t h a t the p a t i e n t ' s general c o n d i t i o n is stable a n d that the s u r g e o n is capable a n d h a s a d e q u a t e facilities. T h e objects o f the i n t e r v e n t i o n include: to to to or
c o n f i r m or establish diagnosis; restore c o n t i n u i t y to a severed o r r u p t u r e d nerve; remove a n o x i o u s agent c o m p r e s s i n g o r d i s t o r t i n g o c c u p y i n g a nerve.
The decision to intervene o n a nerve after injury is never easy, except p e r h a p s in the acute case o f an o p e n w o u n d a n d in cases in which nerve injuries are associated with d a m a g e to m a j o r bones a n d b l o o d vessels. The indications for o p e r a t i o n are p r o b a b l y as follows:
Major nerve injury in the adult upper limb deep paralysis after wounding over the course of a main nerve or injection close to the course of a main nerve; deep paralysis after closed injury, especially highvelocity injury, associated with severe damage to soft tissues, bone or joint; deep paralysis after closed traction injury of the brachial plexus; association of a nerve lesion with evidence of an arterial lesion; association of a nerve lesion with fracture of a related bone requiring early internal fixation; increase in depth of nerve lesion under observation; failure to show evidence of recovery at the expected time after a closed lesion initially thought to be an axonotmesis; failure to show evidence of recovery in conduction block within six weeks of injury; persistent pain almost any interval after injury.
Tidy wounds The ideal course is primary repair of all structures. In most cases, suture of the nerve is possible.
13
distal one-third and proximal two-thirds of the forearm and the gap between healthy vascular stumps ranged from 5 12 cm. Vein grafts were used for the radial and ulnar arteries and for three veins. Primary repair of the nerves was done after shortening the limb bones by about 3 cm. Circulation was restored and, by two years, recovery for the median and the ulnar nerves was useful. Experience from this and from three other cases supports reports from those centres with great experience in replantation of the amputated hand or digit which confirm that primary repair of the nerve gives the best result.
Closed traction lesions Traction lesions involving the post-ganglionic elements, the roots and the trunks of the supraclavicular plexus are associated with arterial injury in some 5% of cases. In the severe traction lesion of the infraclavicular brachial plexus there is rupture of the subclavian or axillary artery in 25% of cases, or more, and this arterial injury offers the strongest possible indication for urgent repair. Admittedly, both patient and surgeon may have had enough after an extended operation to deal with the fractures and the arterial lesion.
Untidy wounds The risk is sepsis. Initial aims include restoration of stability of the skeleton, restoration of the circulation and delayed closure of the skin or early recourse to a pedMe or free cutaneous or myocutaneous flap. The latissimus dorsi flap has proved invaluable in the severely damaged upper limb. Nerves will almost always require grafting and timing is a matter of fine judgement. There are situations, from open fracture or ragged laceration from a saw, where primary repair is justified. In other more contaminated cases, it is safer to return to the field at about two weeks. The wounds of industrial or agricultural machinery, of burn or of penetrating missile injury do not permit, as a rule, primary repair. In these cases, replacement of the nerve stumps in their normal anatomical position and tagging or tethering of the stumps with fine monofilament suture is a useful way of minimizing retraction. The replantation of the amputated limb affords the most uncompromising model of this type of injury. Chen et al (1981) reported the results of a co-operative study between Shanghai, Louisville and Zurich in 181 cases? ~ The best results followed replantation of limbs amputated through the distal forearm and wrist, with useful results being obtained in 79%-83% of cases. The worst results were from replantation of the limb amputated or avulsed at shoulder level. Avulsion injuries fared very much worse than did guillotine or crush injuries. The extent of vascular damage is, in itself, no barrier to successful replantation. In one of our cases, a 28-year-old woman threw herself under a train in an attempt at suicide. The dominant hand was amputated at the junction of the
Nerves injured by fracture or dislocations It is important to remember that nerves are injured by damage to the adjacent skeleton by traction from displacement, which commonly ends in rupture, laceration by a fragment of bone, entrapment within the dislocated joint or in a fracture, and late entrapment or compression from callus. On the whole, dislocations are more damaging. It seems to be widely assumed that the prognosis for nerves injured in this way is good but this not generally the case. A surgeon who considers that the fracture requires open reduction and internal fixation will rarely regret exposing the afflicted nerve at the same time; a nerve palsy is an added indication for open reduction and stabilization. Watson Jones (1930) described one of the earliest series on nerve injuries from fractures and dislocations? 7 It remains one of the best. He and Platt (1928) TM were strongly in favour of the exploration of nerves injured by fractures. Seigel and Gelberman (1991) reviewed the subject thoroughly, finding 85% of nerve palsies recovering from closed fractures and 65-70% after open fractures. 19Of those nerves which went on to recovery, 90% had done so by four months. These cannot have been wholly degenerative lesions. Seigel and Gelberman's indications for intervention include the fact that the fracture needs internal fixation, that there is associated vascular injury, that wound exploration of an open fracture is necessary, and that a fracture or dislocation is irreducible. We might add to this two more: the lesion deepens whilst it is under observation; and the lesion occurred during operation for internal fixation of the fracture.
14
Current Orthopaedics
Where direct suture of a nerve is not possible, then the mainstay in technique remains autologous grafting. The results of operating on peripheral nerves depend to an extent hardly matched in any other branch of surgery on the skill of the surgeon and the quality of the technique. Nerve suture is done when the gap after resection is small, little mobilization of the nerve is needed to close it and the repaired nerve lies without tension and without excessive flexion of adjacent joints. The experimental work of Clarke et al (1992) clearly showed the ill effect of tension on the repaired nerves. 2° The following principles are useful guides: 1. End-to-end suture of the nerves of the brachial plexus above the clavicle or of the accessory nerve, is nerve practicable. 2. Anterior transposition of the ulnar or radial nerve gives, at most, 3 cm. 3. N o gaps in the median nerve in the forearm can be closed by end-to-end suture. It will be seen that, in m a n y circumstances, it is better to bridge a gap with a graft than to force direct suture; it is better to resect healthy bundles and create a wide gap than to resect too little in order to facilitate direct suture. There are promising developments in techniques other than direct suture or autogenous grafting. Glasby and his colleagues 2~43 have shown that freezethawed muscle grafts are a possible substitute for autogenous graft and T h o m a s and Kitchen 24 clarified a particular role for such grafts in the repair of damaged cutaneous nerves provoking significant pain. M c K i n n o n (1996) describes the use of allografts in a 12-year-old boy with a 20 cm gap in the tibial nerve, which was bridged by 8 allografts? 5 I m m u n o suppression was maintained over four months. M c K i n n o n comments 'in the carefully selected patient with an otherwise irreparable nerve injury, consideration of nerve transplantation should be given'. Lundborg and his colleagues have shown functional recovery, to a high degree, following silicone intubation of divided nerves. 26 In 1997, a significant paper appeared describing a prospective randomized trial comparing silicone intubation and suture of median and ulnar nerves in 18 patients. N o significant difference in the outcome between the two groups was noticed. This is impressive work and, as Professor Lundborg has suggested, the technique offers a potential alternative to nerve grafting in some cases.
slips of the peroneal nerve into slits in the muscle. Reinnervation was secured and the development of end plates in response to the entry of the m o t o r axons was shown. The method works in clinical practice; if the musculocutaneous or other working nerve is reimplanted into the muscle, preferably at the point of avulsion, early after injury, the chances of m o t o r power are high. The use of this technique is rarely required, but it should not be forgotten.
RESULTS Measurement of outcome
Seddon (1975) 7 developed a system for measurement of outcome drawn from the Medical Research Council System, which classed results of nerve repair as good, fair, p o o r and bad (Tables 5 & 6). We have simplified this further into good, fair and poor. For some nerves, muscular function is a good deal more important than recovery of sensation and, for the spinal accessory, suprascapular and circumflex, musculocutaneous and radial nerves, little significance is attached to the extent of recovery of cutaneous sensation except when recovery was complicated by severe pain when the result is considered poor Recovery of sensation has been given equal importance to muscle function in the description o f results o f median and Table 5 Medical Research Council system for grading recoveryin skeletal muscle and in cutaneous sensation
Motor recovery M0 M1 M2 M3
M4 M5
Sensory recovery SO $1 $2
Direct muscular neurotizations
Sometimes, a nerve is avulsed from the muscle that it innervates. The two nerves most commonly afflicted in this way are the circumflex and musculocutaneous. Brunelli and Monini (1985) 27 implanted a working nerve directly into the paralysed muscle. They denervated the sural triceps muscle in rabbits and implanted
No contraction Return of perceptiblecontraction in the proximal muscles Return of perceptiblecontraction in both proximal and distal muscles Return of perceptiblecontraction in both proximal and distal muscles of such degree that all important muscles are sufficientlypowerful to act against resistance Return of function as in Stage 3 with the addition that all synergic and independent movementsare possible Complete recovery
$3+ $4
Absence of sensibilityin the autonomous area Recovery of deep cutaneous pain sensibility within the autonomous area of the nerve Return of some degree of superficialcutaneous pain and tactile sensibilitywithin the autonomous area with disappearance of any previous over-reaction Return of sensibility as in Stage 3 with the addition that there is some recoveryof two-point discrimination within the autonomous area Complete recovery
(From Surgical Disorders of the Peripheral Nerves7Ch. 8, with
permission)
Major nerve injury in the adult upper limb Table 6
Table 7
Gradingof results
Motor recovery
Sensoryrecovery
M4 or better M3 M2 MI & O $4 (normal) or $3+ $3 $2 SI & O
Good Fair Poor Bad Good Fair Poor Bad
(From Surgical Disorders of the PeripheralNerves7Ch. 11, with permission) ulnar nerves; indeed, one could argue that sensibility is the most important function of the median nerve. Some allowance is made for recovery of sympathetic efferent activity in this and in the ulnar nerve. The grade excellent is used rarely, in exceptional cases where function is indistinguishable from the normal. 28 Seddon and his colleagues fully recognized the defects and limitations of the MRC system but it has stood the test of time. Kline and Hudson, in 1995, described a valuable grading system for motor and sensory function and for the whole nerve, which is based on great clinical experience. 29 Constant's shoulder assessment system (1997) is valuable in the analysis of circumflex and suprascapular nerve function. 3° The particular difficulties of measurement of limb function in cases of injury to the adult brachial plexus are addressed by Narakas and in the obstetric brachial plexus palsy by Gilbert and Raimondi and no discussion of these lesions can fail to acknowledge these contributions. (see Surgical Disorders o f the Peripheral Nerves, Ch 9 and 10 for review of these methodsT). For more detailed discussion of methods of measurement, the reader is referred to Bonney, who analyses in considerable detail pitfalls and defects in those systems currently used? 1 The spinal accessory nerve This nerve is usually damaged by surgeons. The lesion is crippling: arguably it is the most significant of all nerve injuries within the upper limb. It is a shameful matter that the nerve is so commonly damaged during operations, that diagnosis is usually delayed, and that only exceptionally are urgent efforts made to rectify the situation. Williams and colleagues made a detailed study of 40 of our cases? 2 As they say, 'injury to the accessory nerve results in a characteristic group of symptoms and signs: reduced shoulder abduction, drooped shoulder and pain. Repair of the nerve reduces symptoms in most cases. Some grasp of the surgical anatomy, together with the use of the nerve stimulator, ought to prevent this serious complication of surgery in the neck'. In Williams' series, delay in diagnosis was usual, ranging from immediate to 32 months and in 26 patients pain was severe even at rest, and disturbed sleep.
15
The spinal accessorynerve (59 repairs)
Excellent Good Fair Poor
6 28 15 10
The nerve tO serratus anterior The nerve is most commonly damaged in lesions of the brachial plexus but it is particularly vulnerable for accidental damage where it crosses the first and second rib. When serratus anterior is paralysed, the inferior pole of the scapula does not move forward but slides medially and cranially. Confusion with spinal accessory palsy is a common error. Deep aching pain is common, and sometimes severe. When we have been given the chance to repair the nerve after a stab wound (5 cases) or intra-operatively (6 cases) results have been very good, even better than for almost any other peripheral nerve. Circumflex and suprascapular nerves It is our experience that U K orthopaedic surgeons tend to adopt an expectant approach to circumflex palsy, unlike their more energetic approach to other injuries of peripheral nerves, notably to the brachial plexus. We think that Nunley and GabeP 3 are right when they say, 'if no evidence of clinical or electromyographic recovery is seen at two or three months after injury, exploration should be performed ... recovery is unlikely after twelve months of denervation, and surgical treatment is of negligible benefit in this setting'. Ochiai and his colleagues 34presented very significant work describing the treatment of combined injuries of the circumflex and suprascapular nerves and they showed that the suprascapular nerve might be severely damaged at several places. They recommended that this nerve should be exposed along its entire course as far as infraspinatus and the recommended exposure is described in detail in this valuable paper. Spilsbury and Birch 35 reported findings in 129 nerve injuries in 98 patients (Tables 8 & 9). Spilsbury's myometric Studies suggested that the deltoid muscle was responsible for over 50% of the power of abduction, about 30% of forward flexion power and 80% of extension power at the shoulder. Improvement in strength and in stamina was not impressive even in those cases where the outcome was considered good. Results are bad with associated rupture of the rotator cuff, even in three cases when the cuff was repaired at the same time as grafting the circumflex nerve. Intraarticular fracture provoked post-traumatic arthritis in three more cases. Tight contracture of the capsule was a common contributory factor to iailure, especially after multiple ruptures of nerve trunks. All repairs of the circumflex nerve performed at more than one year from injury failed.
16
Current Orthopaedics Table 8 Circumflex and suprascapular nerves: grading of results Circumflex: Good Fair Poor or bad
Deltoid Deltoid Deltoid
Suprascapular: Good Fair Poor
Abduction 120° or more Abduction 90-120 ° Less
MRC 4 or better MRC 3+ or better Less
Abduction Abduction Less
Elevation at least 120° Elevation 90-120 °
Later rotation 3° or more Lateral rotation 0 30° Less
From Surgical Disorders of the Peripheral Nerves 7, Ch. 11, with permission)
This is one o f the best nerves to repair, so m u c h so t h a t r e p a i r was a t t e m p t e d even in extremely u n f a v o u r a b l e cases w i t h p o s t - i s c h a e m i c fibrosis, after direct d a m a g e to the e l b o w flexor muscles, o r after p r o l o n g e d delay. T h r e e sutures failed a n d these were revised with grafts achieving two g o o d a n d one fair result (Table 10).
extension o f the e l b o w ( M R C 4) followed repair. A s one m i g h t expect, recovery for the p o s t e r i o r interosseous nerve is usually g o o d . Shergill a n d colleagues 36 f u r t h e r s t u d i e d the o u t c o m e o f 260 repairs o f the r a d i a l a n d p o s t e r i o r i n t e r o s s e o u s nerves. Overall, there were 30% o f g o o d results, a n d 28% fair f r o m the 242 r a d i a l nerve repairs. T h e m o s t i m p o r t a n t f a c t o r in the p r o g n o s i s was s h o w n to be the violence o f the injury. Seventy-nine p e r cent o f the o p e n ' t i d y ' repairs achieved a g o o d o r fair result c o m p a r e d to 36% o f cases where there was a s s o c i a t e d arterial injury. T h e r e were very few w o r t h w h i l e results f r o m r e p a i r in which the defect o f the nerve t r u n k exceed 10 cm. D e l a y was i m p o r t a n t , Sixty-five p e r cent o f 38 repairs in the o p e n ' t i d y ' g r o u p p e r f o r m e d within 14 days o f the injury were c o n s i d e r e d good. N o useful results were seen w h e n the interval b e t w e e n injury a n d r e p a i r exceeded twelve m o n t h s . Sixteen o f 18 repairs o f the p o s t e r i o r interosseous nerve achieved a g o o d result.
The radial nerve (Tables 11 & 12)
The median and ulnar nerves
These results are n o t as g o o d as one m i g h t expect; t h e y a p p e a r to be inferior to t h o s e r e p o r t e d b y S e d d o n . 7 U s e f u l wrist extension was r e g a i n e d in twothirds o f patients b u t extension o f the finger a n d the t h u m b in only one-third. I n h i g h lesions o f the p o s t e r i o r cord, the result was g r a d e d as fair if useful
T h e effect o f age a n d o f level o f i n j u r y are p a r t i c u l a r l y evident for these two nerves. Equally, o r even m o r e so, is the effect o f the cause o f i n j u r y a n d the delay b e t w e e n injury a n d repair. C l e a r evidence o f this c o m e s f r o m the study b y C a v a n a g h et aP 7 o f the c o m p l e x infraclavicular i n j u r y in which several nerve
Table 9 Outcome in repairs of the circumflex and suprascapular nerves Circumflex nerve (56 repairs) Good Fair 25 23
Poor 8
Suprascapular nerve (24 repairs): Good Fair 20 2
Poor 2
(From Surgical Disorders of the Peripheral Nerves 7, Ch. 11, with permission)
The musculocutaneous nerve
Table 10 Results of 154 repairs of musculocutaneous nerves (children and adults)
Good Fair Poor Totals
Tidy
Untidy (incl. penetrating missile injuries)
Traction
Total
21 3 1 25
26 8 6 40
55 24 10 89
102 35 17 154
Good: Flexion of elbow. M4 or better; Fair: Flexion of elbow against gravity; Poor:
Good Fair Poor Totals
Tidy
Untidy (inc. penetrating missile wounds)
Traction
Total
12 10 5 27
20 18 16 54
6 19 25 50
38 47 46 131
Good: Extension of elbow, wrist and digits. MRC 4 or better; Fair: Extension of elbow and wrist against gravity; Poor: < M3. (From Surgical Disorders of the Peripheral Nerves 7, Ch. 11, with permission)
M a j o r nerve i n j u r y in the a d u l t u p p e r limb
Table 12 Posterior interosseous nerve (11 cases)
Table 13 Resultsfor nerves injured
Good 8
injured nerves
Fair 2
Poor 1
Good: active extension of fingers and thumb. MRC 4 or better; Fair: active extension of fingers and thumb. MRC 3 or 3+; Poor: less than the above. (From Surgical Disorders of the Peripheral Nerves7, Ch. 11, with permission)
Table 14
Good
Fair
Poor
Total
Median and ulnar Radial and musculocutaneous Suprascapular and circumflex
15 29 12
21 20 3
19 8 3
55 57 18
Totals
56
44
30
130
From Surgical Disorders of the Peripheral Nerves7, Ch. 11, with permission)
Resultsby cause
Lesion
Good
Fair Poor Total
Closed Infraclavicular with supraclavicular involvement Infraclavicular only
1
4
6
11
31
30
19
80
Open
24
10
5
39
Totals
56
44
30
130
(From Surgical Disorders of the Peripheral Nerves7, Ch. 11, with permission)
Table 15 Resultsrelated to interval between injury and repair Lesion
17
Good
Fair
Poor
Total
Table 16 Grading of results in high median and ulnar nerve repair Median Long flexor muscles MRC 4 or better Localization to digit, without hypersensitivity Return of sweating Fair Long flexormuscles MRC 3 or 3+ 'Protective sensation'. Moderate or no hypersensitivity Sweating diminished or absent Poororbad Long flexor muscles MRC 2 or less 'Protective sensation' but severe hypersensitivityor no sensation Good
Ulnar Good
Early: within 14 days Median and ulnar Radial and musculocutaneous Suprascapular and circumflex
14 19 7
13 i0 2
6 1 2
33 30 11
Totals
40
25
9
74
Late: after 14 days (22 weeks on average) Median and ulnar Radial and musculocutaneous Suprascapular and circumflex
1 10 5
8 l0 1
13 7 1
22 27 7
Totals
I6
i9
2I
56
FCU and FDP little and ring MRC 4 or better Intrinsic muscles MRC 2 or better Localization to little and ring fingers. No hypersensitivity. Return of sweating Fair FCU and FDP little and ring fingers MRC 3 or 3+ No intrinsic muscle function 'Protective' sensation little and ring fingers Moderate hypersensitivity Little or no sweating Poor or bad FCU and FDP little and ring fingers MRC 2 No intrinsic muscle function 'Protective' sensation with severe hypersensitivityor no sensation No sweating
(From Surgical Disorders of the Peripheral Nerves7, Ch. 11, with permission)
(From Surgical Disorders of the Peripheral Nerves7, Ch. 11, with permission)
t r u n k s were r u p t u r e d or t o r n by knife or missile, a n i n j u r y complicated by r u p t u r e o f the axillary artery in over o n e - t h i r d o f cases. Results for the i n j u r e d nerve, by cause, a n d by the interval between i n j u r y a n d repair, are set o u t in Table 13 15. The results after repair o f a high m e d i a n a n d u l n a r nerve lesion are, o n the whole, m u c h m o r e m o d e s t t h a n those following m o r e distal repairs, a n d thus a less d e m a n d i n g system o f assessment is used for repairs of these nerves d a m a g e d i n the axilla a n d a r m (Table 16). Results are described in Tables 17 a n d 18.
CONCLUSION
Distal lesions Results for m e d i a n a n d u l n a r nerves in the forearm a n d wrist were presented by Birch a n d Raji; 28 the m e t h o d o f assessment used in that series is set out in Table 19 a n d the results for 254 nerves are set out i n Tables 20 a n d 21.
T h e evidence shows that of all the factors relating to the o u t c o m e o f nerve repair delay is the m o s t significant o f those within the control o f the surgeon, b u t this counsel o f perfection must be tempered by the practical problems facing the surgeon called u p o n to treat patients with severe injuries. Stabilization of the skeleton, restoration o f circulation, a d e q u a t e t r e a t m e n t of the w o u n d a n d recognition o f the nerve lesion are admirable aims. N o great h a r m comes from d o i n g what is necessary before r e t u r n i n g later to the nerve itself, or perhaps referring the p a t i e n t to a n interested colleague. Diagnosis is (nearly) all. This particularly applies to the serious p r o b l e m o f nerves i n j u r e d during operation, which seems to be increasing. The difficulties facing surgeons in these circumstances are m a d e m o r e by changes in terms o f e m p l o y m e n t a n d by early recourse to so-called 'disciplinary' procedures
18 Current Orthopaedics Table 17
Results in 85 repairs of median nerves in axilla or arm (adults and children)
Good Fair Poor or bad Total
Tidy
Untidy (incl. penetrating missile injuries)
Traction
Total
6 8 3 17
4 8 12 24
3 15 26 44
13 31 41 85
a This includes 28 repairs of either lateral or medial root of the nerve in the axilla. (From Surgical Disorders of the Peripheral Nerves7, Ch. 11, with permission)
Table 18
Results of 60 repairs of medial cord or ulnar nerve in axilla and arm (children and adults)
Good ° Fair Poor or bad b TOTAL
Tidy
Untidy (incl. penetrating missile injuries)
Traction
Total
3 5 2 10
2 13 10 25
0 7 18 25
5 25 30 60
"All 5 good results followed repair within 48 hours of injury - 2 in children; b Results of repair after 3 months of injury were always poor in the untidy and traction lesions. (From Surgical Disorders of the Peripheral Nerves7, Ch. 11, with permission)
Table 19
Methods of grading results of median and ulnar nerves
Grade
Motor
Sensory
Equivalent on Seddon's grading
Excellent
Power MRC 5 No wasting or deformity No trophic changes Power MRC 4 to 5. Abolition of paralytic deformity Minimal pulp wasting MRC 3 or more. Some sweating. Pulp wasted
Function indistinguishable from normal hand. Good stereognosis, no hypersensitivity. 2PD" equivalent to uninjured digits Accurate speedy localization. Can recognize texture or objects. Minor cold sensitivity and hypersensitivity. 2PD < 8 mm at tips of fingers Accurate localization to digit. No stereognosis. 2PD > 8 mm. Significant cold sensitivity and hypersensitivity No sensation or severe cold sensitivity and hypersensitivity
Good M5, $4
Good
Fair
Poor and bad
MRC 3 or less. No sweating, Trophic changes
Good M5, $3+
Fair. M3, $3
Bad M 01 or 2S 01 or2
"Two-pointdiscrimination (From Surgical Disorders of the Peripheral Nerves7, Ch. 11, with permission)
Table 20 Repair of 119 median nerves in adults (16-65 years) in tidy wounds from distal wrist crease to elbow crease Primary repair
Delayed suture
Graft
Total
Excellent Good Fair Poor or bad
5 27 12 2
1 9 14 7
0 12 25 5
6 48 51 14
TOTAL
46
31
42
(From Surgical Disorders of the Peripheral Nerves7, Ch. 11, wi~/h permission)
Table 21 Repair 145 ulnar nerves in adults (16-65 years) in tidy wounds from distal wrist crease to elbow crease Primary repair
Delayed suture
Graft
Total
Excellent Good Fair Poor or bad
8 25 13 0
1 6 16 9
2 22 27 16
11 53 56 25
TOTAL
46
32
67
145
(From Surgical Disorders of the Peripheral Nerves7, Ch. 11, with permission)
M a j o r n e r v e i n j u r y in the a d u l t u p p e r l i m b
by T r u s t s o r others. T h i s g r a v e issue is d e b a t e d in c o n s i d e r a b l e d e p t h by B o n n e y ¢ 8 r e a d e r s are u r g e d to s t u d y this. REFERENCES
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