RADIAL NERVE palsy.pptx

radial nerve palsy general principles

1. RADIAL NERVE INJURIES

2. ORIGIN OF RADIAL NERVE AND IT’S COURSE BRACHIAL PLEXUS Five roots contribute to the formation of the plexus for the upper limb . They are the fibres that remain in the anterior rami of C5–8 and T1 after these have given their segmental supply to the prevertebral and scalene muscles. They are to divide into anterior and posterior divisions to supply the flexor and extensor compartments respectively , But before doing so they unite to form three trunks in the following manner: Of the five roots of the plexus the upper two unite to form the upper trunk, the lower two unite to form the lower trunk, and the central root runs on as the middle trunk. The five roots lie behind the scalenus anterior muscle and emerge from between it and scalenus medius to form the trunks which cross the lower part of the posterior triangle of the neck.

3. Each of the three trunks divides into an anterior and a posterior division behind the clavicle. Here, at the outer border of the first rib, the upper two anterior divisions unite to form the lateral cord, the anterior division of the lower trunk runs on as the medial cord, while all three posterior divisions unite to form the posterior cord. Thus the roots are between the scalene muscles, trunks in the (posterior) triangle, divisions behind the clavicle, and cords in the axilla. An extension of the prevertebral fascia in the neck surrounds the axillary artery and cords; local anaesthetics are injected into this axillary sheath to produce a brachial plexus nerve block.

4. The radial nerve (C5–8, T1) is the continuation of the posterior cord, and is the largest branch of the whole plexus. It crosses the lower border of the posterior axillary wall, lying on the glistening tendon of latissimus dorsi . It passes out of sight through the triangular space below the lower border of this tendon as it lies in front of teres major, between the long head of triceps and thehumerus . The axillary nerve passes backwards below subscapularis through the quadrangular space. Before disappearing it gives nerves of supply to the long head of triceps and the medial head (a nerve which accompanies the ulnar nerve along the medial side of the arm) and a cutaneous branch which supplies the skin along the posterior surface of the arm ( posterior cutaneous nerve of the arm).

5. The radial nerve (C5–8, T1) is the nerve of the extensor compartments of the arm and forearm, supplying skin over them and on the dorsum of the hand. It spirals across the back of the humerus, between the lateral and medial heads of triceps, lying on the radial groove of the bone, deep to the lateral head . It pierces the lateral intermuscular septum one-third of the way down from the deltoid tuberosity to the lateral epicondyle. In the flexor compartment of the lower arm it descends in the intermuscular slit between brachialis and brachioradialis. After giving off the posterior interosseous branch, the rather slender remnant, purely cutaneous now, retains the name of radial nerve. It runs down the flexor compartment of the forearm,winds around the lower end of the radius deep to the tendon of brachioradialis and crosses abductor pollicis longus, extensor pollicis brevis and extensor pollicis longus (as one of the contents of the anatomical snuffbox) to reach the back of the hand. Here it supplies the skin of the radial two and a half or three and a half digits (falling short of the nail beds and distal and middle phalanges) and a corresponding area of the dorsum of the hand. The surface marking of the nerve is from the point where the posterior wall of the axilla and arm meet to a point two-thirds of the way along a line from the acromion to the lateral epicondyle, and thence to the front of the epicondyle

6. Branches of Radial Nerve The posterior cutaneous nerve of the arm arises in the axilla and pierces the deep fascia to supply a strip of skin along the extensor surface of the arm down to the elbow. The triceps is supplied by four radial nerve branches. They arise as nerves to the long, medial, lateral and medial heads, the first two being given off in the axilla and the last two behind the humerus. The first branch to the medial head (the ulnar collateral nerve) runs down with the ulnar nerve to enter the lower part of the medial head. The second branch to the medial head continues deep to triceps to supply anconeus . The lower lateral cutaneous nerve of the arm pierces the lateral head of triceps to supply skin over the lateral surface of the arm down to the elbow. In common with it arises the posterior cutaneous nerve of the forearm which runs straight down behind the elbow to supply a strip of skin over the extensor surface of the forearm as far as the wrist.

7. While lying in the flexor compartment of the forearm between brachialis and brachioradialis, the main trunk gives a small branch to the lateral part of brachialis and supplies brachioradialis and extensor carpi radialis longus. At the level of the lateral epicondyle it gives off the posterior interosseous branch , and then continues on as the terminal cutaneous branch. The posterior interosseous nerve supplies extensor carpi radialis brevis and supinator in the cubital fossa, and then spirals down around the upper end of the radius between the two layers of supinator to enter the extensor compartment of the forearm. It crosses abductor pollicis longus , dips down to the interosseous membrane and runs to the back of the wrist. In the extensor compartment it supplies seven more muscles; three extensors from the common extensor origin ( extensor digitorum , extensor digiti minimi , and extensor carpi ulnaris ), the three thumb muscles ( abductor pollicis longus , extensor pollicis brevis and extensor pollicis longus ) and extensor indicis . It is sensory to the wrist and carpal joints.

8. Radial Nerve Injury The nerve is most commonly injured high up, by fractures of the shaft of the humerus . The characteristic lesion is ‘wrist drop’ with inability to extend the wrist and metacarpophalangeal joints (but the interphalangeal joints can still be straightened by the action of the interossei and lumbricals). Sensory loss is minimal and usually confined to a small area overlying the first dorsal interosseous, on account of overlap from the median and ulnar nerves. Transient paralysis may be due to improper use of a crutch pressing on the nerve in the axilla , or ‘Saturday night palsy’ from draping the arm over a chair when in a state of diminished consciousness. With such high injuries, triceps paralysis can be detected by testing elbow extension. As branches to the long and medial heads of triceps arise in the axilla, elbow extension is not lost after nerve injury following humeral shaft fracture.

9. COMMON CAUSES OF RADIAL NERVE PALSY Axilla-Aneurysm axillary vessels, Crutch palsy. Spiral groove- Humerus shaft fracture(Holstein lewis fracture) Saturday night palsy Torniquet palsy Elbow- Elbow dislocation Fracture radius neck Monteggia fracture dislocation(PIN palsy)

10. LOCALIZING RADIAL NERVE PALSY Very high radial nerve injury Lesion in axilla Weak elbow extension ( tricep palsy) Wrist drop (ECRL palsy) Finger thumb drop(EDC, EPL,apl palsy) Sensory loss below midarm 2) High radial nerve injury Lesion in midarm Normal elbow extension Wrist drop (ECRL palsy) Finger thumb drop(EDC, EPL,apl palsy) Sensory loss below midarm 3) Low radial nerve palsy Below elbow lesion Normal wrist extension( ECRL spared) Finger thumb drop(EDC, EPL,apl palsy) Sensory loss 1 st web space dorsally

11. CLASSIFICATION OF NERVE INJURY BASED ON CLINICAL EXAMINATION 1. Tidy wound: Caused by knife, glass, or the surgeon’s scalpel. Damage is confined to the wound. Primary repair of all divided structures is desirable. 2. Untidy wound: Commonly caused by open fractures or by penetrating projectile injury. There is extensive tissue damage with a high risk for sepsis. Arterial injury is common. A contaminated wound from a close-range shotgun injury is one example in which urgent repair cannot be entertained. There is a risk for sepsis from dead or devitalized tissue or from unrecognized small fragments of foreign material; the extent of intraneural longitudinal damage cannot easily be ascertained in a freshly exposed wound. Sepsis greatly compounds the problem by causing even more longitudinal destruction within the nerve. 3. Closed-traction injury: Such injuries are very destructive of nerves and axial vessels.170 There is wide retraction of ruptured nerves and vessels, together with considerable longitudinal damage within the ruptured trunk. The outcome after nerve repair for this type of injury, when complicated by an arterial lesion, is the worst of all the groups

12. Tinel sign can be summarized as follows: • A strongly positive Tinel sign over a lesion soon after injury indicates rupture of the axons. This sign has been found regularly on the day of injury, most especially with closedtraction rupture. • Regeneration of axons, either spontaneous or after repair of the nerve, can be confirmed when the centrifugally moving Tinel sign is persistently stronger than that at the suture line. • After a 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 another lesion impeding regeneration. • The Tinel sign advances more swiftly in cases of axonotmesis (i.e., ~2 mm/day) than it does after nerve repair. It also is faster in the proximal segment of the limb than in the distal. In the axilla, rates of progress of 3 mm/day are not unusual. • The Tinel sign should be reserved for traumatic neuropathy and is indicative of a degenerative lesion, not a conduction block. • Tinel himself made a clear distinction between the preceding and the sensitivity of the nerve trunk in cases of “neuralgia.

13. CLINICAL ASSESMENT OF MUSCLES SUPPLIED BY RADIAL NERVE ASSESSING SUPINATOR STRENGTH ASSESSING TRICEPS STRENGTH SHOWING BRACHIORADIALIS CONTRACTION RESISTED EXTENSION IN ULNAR DEVIATION TO EMPHASIZE EXTNSOR CARPI ULNARIS

14. RESISTED EXTENSION IN RADIAL DEVIATION TO EMPHASIZE EXTNSOR CARPI RADIALIS LONGUS AND BREVIS ASSESSING EXTENSOR DIGITORUM COMMUNIS ASSESSING EXTENSOR DIGITI MINIMI ASSESSING EXTENSOR INDICES

15. A, Assessing thumb extensor strength. B, Assessing extensor pollicis longiis strength in isolation. A, Assessing thumb extensor strength. B, Assessing extensor pollicis longiis strength in isolation. ASSESSING ABDUCTOR POLLICIS LONGUS

16. DIAGNOSTIC IMAGING High-resolution ultrasonography (i.e., 17 MHz) has great potential in the early detection of ruptures or other serious injuries to nerves . It has been shown to be reliable in identifying the nerve, confirming the level of injury, and demonstrating continuity or interruption of fascicles. T his have found that interpretation of ultrasound findings is much more difficult in cases evaluated late, where there is abundant fibrosis around the nerves. Magnetic resonance imaging (MRI) MRI can accurately assess the physical integrity of the nerve immediately after injury and provide valuable information for surgical decision making. Intraneural and perineural injuries also can be identified with both of these techniques. Ultrasound axial image at 17 MHz demonstrates severe thickening and loss of fascicular architecture in posterior and lateral cords, with preservation of normal appearance in the medial cord.

17. ELECTRO-DIAGNOSTIC STUDIES NERVE CONDUCTION STUDY

18. ELECTRO MYO GRAPHY

19. TREATMENT

20. Exposure of radial nerve in middle and distal thirds of arm. A, Skin incision begins at posterior margin of deltoid muscle and extends distally in midline and laterally and anteriorly. It ends at interval between brachioradialis and brachialis. B, Posterior skin flap has been dissected and retracted; deep fascia is incised in line with skin incision. Dotted line indicates incision in triceps muscle between long and lateral heads. C, Radial nerve and accompanying vascular bundle have been exposed by retraction of these two heads of triceps muscle. Radial nerve has been dissected to point at which it passes beneath lateral head of triceps muscle. D , Arm is externally rotated a few degrees. Interval between proximal end of brachioradialis and brachialis is to be dissected, exposing radial nerve along anterolateral aspect of humerus. E, Dotted line indicates incision through which lateral head of triceps is mobilized from underlying bone, facilitating exposure of radial nerve deep to it. F, Exposure.

21. Exposure of posterior interosseous branch of radial nerve for repair or decompression in radial tunnel syndrome. A, Line of incision, forearm prone, elbow flexed. B, Nerve exposed. C, Diagram of course of nerve with arm in position A. D, Line of incision, elbow extended.

22. METHODS OF CLOSING GAPS Interfascicular nerve grafting is the preferred method for bridging gaps, although extensive mobilization techniques have been described. In the axilla and in the proximal arm on the medial side proximal to the point of emergence of the branches to the triceps, closing a gap of more than 6 to 7 cm is difficult without sacrificing the branches to the triceps; this is hardly justifiable. Resecting the humerus rarely is feasible at this level. In the middle third of the arm, defects of 10 to 12 cm can be closed by mobilizing the nerve from the elbow to the clavicle and widely stripping the branches of the nerve, by flexing the elbow, by externally rotating and strongly adducting the arm across the chest, and, if necessary, by sacrificing the branch to the brachioradialis (if the biceps is functioning). Transposing the nerve beneath the biceps anterior to the humerus, advocated by most authors on this subject, adds variable length and occasionally is worthwhile. In the presence of a nonunited fracture of the humerus, 3 to 4 cm of the bone can be resected, but if the procedures just mentioned are used, resecting part of a normal humerus almost never should be necessary to repair the radial nerve. Before such extreme dissection and awkward positioning are attempted, serious consideration should begiven to interfascicular nerve grafting.

23. RESULTS OF SUTURE OF THE RADIAL NERVE Only motor recovery is important in suture of the radial nerve. Among patients with sutures of this nerve, 89% obtain recovery of proximal muscles, 63% regain useful function of all muscles supplied by the radial nerve, and 36% regain some fine control of the extensors of the fingers and thumb. When circumstances are most favorable, more than three fourths of these patients recover useful function of all the muscles supplied by this nerve. Lee et al. reported good-to-excellent motor recovery in six patients with high radial nerve palsy treated with 9 to 11 cm of interfascicular nerve grafting and recommended nerve reconstruction before resorting to tendon transfers. Pan et al. found better outcomes of finger and thumb extension with injuries occurring distal to the lateral epicondyle. Wrist extension recovered in at least 80% of the patients, regardless of the level of injury in relation to the humerus. Primary repair of transected radial nerves associated with open humeral fractures is not recommended because of poor recovery.

24. CRITICAL LIMIT OF DELAY OF SUTURE Return of motor function should not be expected when suture has been delayed for more than 15 months. Zachary found that return of function in muscles innervated by the posterior interosseous nerve is unlikely if the delay is more than 9 months.

25. RECOVERY AFTER REPAIR The quality of recovery after repair depends chiefly on the number of axons reaching their correct targets and on the later development and myelination of these axons. Some factors that influence this regeneration process include the following: • Delay between injury and repair • Quality of the apposed nerve ends • Quality and accuracy of fascicular matching • Degree of damage to the nerve ends during the repair operation • Length of gap after resection of the damaged nerve stumps • Number of channels provided by the interposed graft for regenerating columns • Extent of fibroblastic infiltration of the stumps and interposed graft • Rate of regeneration

26. Sensibility Recovery Sequence I Myelinated and unmyelinated fibers (restore perception of pain and temperature) Pseudomotor function II Touch perception Perception of 30 cycle per second (cps) of vibratory stimulus Perception of moving touch Perception of constant touch Perception of 256 cps vibratory stimulus

27. TAKE AWAYS FROM RADIAL NERVE REPAIR • The outcome after repair of the radial nerve is generally better than that for the median and ulnar nerves. The superficial radial nerve is a significant exception. • Every reasonable effort should be made to regain extension of the elbow and wrist by nerve repair or transfer. • Operating on a closed fracture converts it into an open one no matter how small the incision. If surgical treatment of a closed fracture with radial palsy is undertaken, the nerve should be exposed. • A radial palsy that complicates surgical intervention in the arm means that the nerve has been cut unless and until proven otherwise. • Radial palsy is crippling. Well-made orthoses help. The surgeon must be alert to the risk of fixed deformity. • Early forearm tendon transfers are indicated when prognosis is poor (e.g., high traction injury, long defect, late presentation).

28. Direct Suture or Graft? End-to-end suture is preferable as long as the gap after resection is small, little mobilization of the nerve is needed to close the gap, and the repaired nerve lies without tension and without excessive flexion of the adjacent joints. The end-to-end suturing of the nerves of the brachial plexus above the clavicle or of the accessory nerve is ever practicable and always prefer to use interposed grafts even if they are short. The nerves cannot be effectively mobilized, and it is difficult to protect the repair by splinting or with an orthosis. Elastic recoil of nerve stumps occurs once the trunk has been severed, and it is much easier to overcome this recoil without undue tension on the nerve when the operation is performed within days of the injury. The longer surgery is delayed, themore likely it is that grafting will be required because the stumps become embedded in scar tissue, resulting in an increase in interneural scarring.

29. Direct observation indicates that anterior transposition of nerves, such as the ulnar or the radial, gains, at most, 3 cm. Experience shows that it is necessary to use grafts for all delayed repairs in which 1 cm of the nerve has been lost. One simple test about the advisability of direct suturing of a nerve trunk at the wrist or in the forearm involves passing an epineurial suture of 7-0 nylon with the wrist flexed to no more than 30 degrees. If this suture draws the stumps together without tearing the epineurium and without causing blanching of the epineurial vessels, suturing is a reasonable solution. Failing that, grafting is necessary. It is found grafting necessary in all cases of closed-traction rupture of the supraclavicular brachial plexus, in virtually all cases of compound nerve injury caused by fracture, and in a great majority of nerves transected in “untidy” wounds. Closed traction lesion of the brachial plexus exposed 4 days after injury. The red sling surrounds the stump of C6, the stump of C5 lies above it, and the stump of C7 lies deep to it.

30. Radial Nerve Palsy Associated With Fractures of the Humerus The most common radial nerve palsy encountered by most hand surgeons occurs after fracture of the shaft of the humerus. About 12% of these fractures are complicated by radial nerve Injury. Preferable P olicy is to advise expectant treatment to most patients with radial nerve palsy associated with humeral shaft fractures that have been managed nonoperatively. I only consider exploration of the nerve after a realistic waiting period, estimated on the basis of Seddon’s work . If, however, the fracture requires plate fixation, the radial nerve should be identified and examined during the procedure.

31. Biggest dilemma is the patient who presents with a radial nerve palsy after plate fixation of the humerus. In this scenario review the operation notes to see whether the radial nerve was identified and protected throughout the procedure . This helps a surgeon estimate the likelihood of the nerve being intact and capable of spontaneous recovery with axonotmesis, or divided/crushed (by a plate) with no prospect of recovery. I then discuss the options of immediate reexploration , or expectant treatment for at least 12 weeks, with the patient and together we devise an agreed-on treatment plan that suits the patient’s circumstances and psyche and reflects his or her preferences David Green suggests that it is illogical to explore the radial nerve at 6 to 12 weeks. If the decision has been made to await spontaneous recovery of function, then sufficient time must be allowed and < 12 weeks is insufficient.

32. TREATMENT OPTIONS FOR IRREPAIRABLE RADIAL NERVE INJURY Requirements for a Patient With Radial Nerve Palsy A patient with an irreparable radial nerve palsy needs to be provided with wrist extension (2) finger (MP joint) extension, (3) a combination of thumb extension and abduction. Nonoperative Treatment The most important aspects of nonoperative management of a patient with radial nerve palsy are maintenance of full passive range of motion in all joints of the wrist and hand and prevention of contractures, including contracture of the thumb–index web.

33. A person who does data entry and wishes to continue working might be able to do so with the dynamic finger and thumb extension splint , whereas an insurance salesperson who is more concerned about appearance would probably be content with a small, inconspicuous volar cock-up wrist splint. If a wrist splint is worn only during the day, then it is recommended that a splint, which holds the wrist and fingers in extension, be worn at night; otherwise, the disturbed balance of the wrist can result in loss of fiber length of the flexor muscles, making it more difficult to achieve normal balance after the final nerve recovery or operation.

34. OPERATIVE TREATMENT TENDON TRANSFER I f a good repair of the nerve is achieved, most would wait several months (at least 5 or 6 after injury in the middle third of the upper arm) to allow nerve regeneration to occur. They would only proceed to tendon transfers if it was clear that inadequate muscle reinnervation had occurred by both clinical and electrodiagnostic criteria. There does not seem to be any time limit as to how long a delay can be tolerated before transfers are done after nerve injury. Brodman reported successful transfers 24 years after radial nerve injury, despite what he described as “ gelatinous degeneration ” (i.e., translucent appearance) of the paralyzed tendons at the time of operation.

35. FLEXOR CARPI ULNARIS TRANSFER 3 3 1 2 Incisions used in a flexor carpi ulnaris combination of transfers

36. PT to ECRB • Take a strip of periosteum from the radius in continuity with the PT insertion to lengthen the transfer. • Free up the muscle proximally to gain maximum excursion. • Pass the tendon around the radial border of the forearm superficial to the BR and ECRL. • Suture only into the ECRB—do not include the ECRL—just distal to the musculotendinous junction. • Tension: Wrist in 45 degrees of extension PT under maximum tension If necessary, reinforce juncture with a strip of free tendon graft

37. FCU to EDC • Do not use FCU for tendon transfer in posterior interosseous nerve palsy. • The FCU must be freed up extensively, requiring a long incision. • Generously excise muscle from the distal half of the tendon to reduce bulk. • Free up the muscle sufficiently to allow it to be redirected obliquely across the forearm. • Protect the muscle’s innervation in the proximal muscle belly. • Create a straight line of pull from the medial epicondyle to the EDC. • Tendon juncture: weave the FCU through the EDC tendons at a 45-degree angle well proximal to the dorsal retinaculum. • Include the EDM only if there is a lag in extension of the small finger. • Tension: Wrist in neutral (0 degrees) MP joints in neutral (0 degrees) FCU under maximum tension

38. PL to Rerouted EPL • Transect the EPL at its musculotendinous junction. • The EPL tendon is rerouted to pass along the radial border of the thumb metacarpal. • The tendon juncture of PL to EPL is in the snuffbox superficial to the dorsal retinaculum in line with the thumb metacarpal. • Tension: Wrist in neutral (0 degrees) Maximum tension on distal stump of EPL PL under maximum tension

39. FDS to EDC and EPL Divide the FDS tendons into III and IV in the distal palm proximal to the chiasma. • To minimize adhesions in passing through the interosseous membrane, excise a large opening in the interosseous membrane and pass the muscle bellies through. • Tension: Wrist in 20 degrees of extension Fingers and thumb held in a fist by an assistant FDS under maximum tension

40. • FCR-to-EDC Transfer Divide the FCR near its insertion and pass it subcutaneously around the radial border of forearm. • Divide the EDC tendons just proximal to the retinaculum, and reposition the stumps superficial to the retinaculum. • Tension: Wrist in neutral (0 degrees) MP joints in neutral (0 degrees) FCR under maximum tension

41. Nerve Transfer as an Alternative to Tendon Transfer Direct transfer of functioning, intact nerves to denervated muscles (neurotization) is used to restore function in patients with brachial plexus palsy when no other option is available. The same concept has been reported in a few cases to restore wrist, finger, and thumb extension in radial nerve palsy The technique is based on one of the principles of tendon transfer: that the loss of the normal function of the muscle(s) used for harvest of the donor nerve(s) is not critical, and that its loss can be accommodated by other functioning musculotendinous units.

42. Neurotization is not an option if: (1) the paralyzed musculotendinous unit with a function that is to be restored was damaged in the injury that caused the nerve palsy; (2) the musculotendinous unit is tethered by scar tissue; and (3) a prolonged time interval between nerve injury and neurotization has resulted in the inability of the recipient muscle to function after reinnervation. The potential benefits of neurotization over tendon transfers are that it avoids the needs for prolonged splintage to protect transfers or multiple skin scars to fashion the musculotendinous transfers. However, the recovery of function is protracted in comparison to tendon transfer. Restoration of Radial Nerve Function Restoration of function is achieved by exposing: (1) the median nerve and its branches for FDS and FCR/PL; (2) the radial nerve and its branch to the ECRB and; (3) the posterior interosseous nerve. The FDS branch is neurotized to the nerve to ECRB, and the FCR/PL branch to the posterior interosseous nerve

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