Radial nerve

radial nerve injury

1. RADIAL NERVE ANATOMY AND RADIAL NERVE INJURies By:dr.amit kumar choudhary Dept of plastic surgery, RIMS, IMPHAL

2. The radial nerve (C5, 6, 7, 8, T1) is the continuation/terminal branch of the posterior cord of brachial plexus ANATOMY

3. In the axilla RN lies anterior to subscapularis, teres major and LD RN leaves the axilla via the triangular space Motor supply: long head of Triceps Sensory supply: Posterior cutaneous nerve of arm

4. In the arm Lies in the spiral groove (posterior) , accompanied profunda brachii artery • Motor supply: BR, ECRL, Brachialis(Shared) Motor: Triceps, Anconeus Sensory: posterior cutaneous nr. of forearm lower lateral cutaneous nr. of arm Re-enters anterior compartment by piercing Lateral Intermuscular Septum

5. In the ELBOW Anterior to lateral epicondyle, RN divides into its terminal branches Superficial radial sensory nerve Posterior Interosseous Nerve (PIN) and

6. IN THE FOREAEM - Posterior Interosseous nerve reaches the back of the forearm by passing round lateral aspect of the radius between the two heads of supinator -As it emerges from supinator posteriorly,The nerve at first lies between the superficial and deep extensor muscles -At the distal border of extensor pollicis brevis, it passes deep to extensor pollicis longus and, diminished to a fine thread, descends on the interosseous membrane to the dorsum of the carpus- supply carpal ligaments and articulations extensor indicis

7. MOTOR SUPPLY PIN -ECRB -Supinator -ECU -EDC -APL -EPL -EPB -EI RADIAL -Triceps - Anconeus -Brachioradialis -ECRL

8. THUMb EXTENSION 1. ABDUCTOR POLLICIS LONGUS Seen and felt at radial aspect of anatomical snuff box when thumb and wrist are abducted against resistance at carpometacarpal joint 2. EXTENSOR POLLICIS LONGUS Palpated at ulnar border of anatomical snuff box when thumb is extended at inter- phalyngeal against resistance 3. EXTENSOR POLLICIS BREVIS Felt at radial border of anatomical snuff box, lying medial to the tendon of APL when the metacarpophalyngeal joint of thumb is extended against resistance

9. FINGER EXTENSION EXTENSOR DIGITORUM Tendons readily felt usually seen, when the fingers are extended against resistance and forearm pronated 2. EXTENSOR DIGITI MINIMI Extending the little finger while holding the remainig fingers flexed at metacarpo-phalyngeal joint 3. EXTENSOR INDICIS Extending the index finger while holding the remaining fingers flexed at metacarpo-phalyngeal joint

10. WRIST EXTENSION Extensor carpi radialis longus Can be palpated when the wrist is extended and abducted against resistance when forearm pronated 2. Extensor carpi radialis brevis Can be palpated when the wrist is extended and abducted against resistance when forearm pronated 3. Extensor carpi ulnaris Can be palpated when the wrist is extended and adducted against resistance when forearm pronated at the lateral groove that over lies the posterior subcutaneous border of ulna radialis brevis

11. TRICEPS Fibres palpated during elbow extension against resistance BRACHIORADIALIS Seen and felt when semi-pronated forearm is flexed against resistance SUPINATOR Too deep to be palpated and independent testing is difficult Supination produced after making biceps inactive( Supination with full elbow extension)

12. Sensory SUPPLY

13. RADIAL NERVE INJURIES AETIOLOGY -Associated with fracture humerus -Gunshot injuries -Injuries with sharp objects -Iatrogenic others -Compression neuropathies

14. CLASSIFICATION TRADITIONAL METHOD- Not accurate -HIGH(above elbow) -VERY HIGH(involving triceps) -LOW(below elbow) WHAT IS IMPORTANT TO BE CLASSIFIED Complete radial nerve palsy vs Posterior Interoessous nerve palsy

15. PHYSICAL EXAMINATION OF NERVE INJURY - The Tinel sign - Wound Inspection - Tidy/Untidy/Closed traction injury - Neurologic examination - 1. Assessment of all muscles distal to injury 2. Sensory examination of affected and surrounding dermatomes - Neurophysiological Investigations : Electrodiagnosis

16. NONOPERATIVE MANAGEMENT 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 Many types of splints have been described 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

17. A person- does data entry; wishes to continue working Able to do so with the dynamic finger and thumb extension splint An insurance salesperson who is more concerned about appearance Be content with a small, inconspicuous volar cock-up wrist splint

18. Early Transfers (Internal Splint) Greatest functional loss after radial nerve injury is weakness of power grip as a result of loss of wrist extension Burkhalter, strong advocate of early palliative tendon (PT)-to- ECRB transfer This eliminates the need for an external splint and significantly improves power grip and hand function- Splintage He suggested that the transfer be done at the same time as radial nerve repair or as soon as possible thereafter- Helper The tendon juncture is done end-to-side so that the ECRB remains in continuity and can function in its own right as a wrist extensor should successful reinnervation occur- Substitute

19. OPERATIVE TREATMENT 1. Nerve Repair 2. Nerve Repair/Grafting Vs Tendon Transfers 3. Principles Of Tendon Transfers 4. Timing Of Tendon Transfers 5. Requirements 6. Historical Review 7. Tendon Transfer Techniques

20. NERVE REPAIR Nerve Resection and Neurolysis Nerve Grafting (Other Methods Vascularized Nerve Graft Freeze-Thawed Muscle Graft Entubulation ) Homo-grafts Nerve Transfer

21. Reasons to not proceed with repair of a transected nerve: The general condition of the patient The attributes and skills of the operating team and the availability of specialized equipment Uncertainty about the viability or state of the nerve trunks Eg : In injuries torn by a saw or a bullet The risk for local or systemic sepsis When the condition of the nerve is such that function will more surely and more rapidly be restored by musculotendinous transfer

22. NERVE REPAIR/GRAFTING Vs TENDON TRANSFERS First decision to make -attempt belated repair of nerve or restore lost function with tendon transfers The time since injury is a critical factor, but late repair of the radial nerve can produce reasonably good results at least in part because the nerve is almost entirely motor and the paralyzed muscles are often reasonably close to the site of injury.

23. PRINCIPLES OF TENDON TRANSFERS

24. PRINCIPLES OF TENDON TRANSFERS Prevention and Correction of Contracture

25. PRINCIPLES OF TENDON TRANSFERS Prevention and Correction of Contracture -Far easier prevented than corrected -No Tendon transfer can move a stiff joint -Impossible for a joint to have more action postoperatively than it had preoperatively

26. PRINCIPLES OF TENDON TRANSFERS Prevention and Correction of Contracture Tissue Equilibrium

27. PRINCIPLES OF TENDON TRANSFERS Prevention and Correction of Contracture Tissue Equilibrium -implies that 1.soft tissue induration has resolved 2.wounds have matured 3.joints are supple 4.scars are as soft as they are likely to become -Performing tendon transfers, or any elective operation, before tissue equilibrium has been reached is to invite disaster

28. PRINCIPLES OF TENDON TRANSFERS Prevention and Correction of Contracture Tissue Equilibrium Adequate Strength

29. PRINCIPLES OF TENDON TRANSFERS Prevention and Correction of Contracture Tissue Equilibrium Adequate Strength Work capacity of a muscle is related to its volume Relative strengths (and excursions) of the donor muscle, as well whose function they will replace, should be as well matched as possible Transfer to replace inevitably weakens donar , typically by one grade on the rather imprecise Medical Research Council (MRC) grading system.

30. PRINCIPLES OF TENDON TRANSFERS Prevention and Correction of Contracture Tissue Equilibrium Adequate Strength Amplitude of Motion

31. PRINCIPLES OF TENDON TRANSFERS Prevention and Correction of Contracture Tissue Equilibrium Adequate Strength Amplitude of Motion -Surgeon must have an appreciation of the amplitude of tendon excursion for each muscle Wrist flexors and extensors- 33 mm Finger extensors and (EPL) -50 mm Finger flexors - 70 mm - Thus, a wrist flexor cannot be expected to restore full range of active motion by a finger extensor

32. PRINCIPLES OF TENDON TRANSFERS Prevention and Correction of Contracture Tissue Equilibrium Adequate Strength Amplitude of Motion Straight Line of Pull

33. PRINCIPLES OF TENDON TRANSFERS Prevention and Correction of Contracture Tissue Equilibrium Adequate Strength Amplitude of Motion Straight Line of Pull -The transfer must run in a straight line from its own origin to the insertion of the tendon it is to drive -If a tendon transfer does not, -1. increased force needs to be expended to overcome friction with surrounding soft tissues and -2. transfer will try to migrate so that it does run in a straight line.

34. PRINCIPLES OF TENDON TRANSFERS Prevention and Correction of Contracture Tissue Equilibrium Adequate Strength Amplitude of Motion Straight Line of Pull One Tendon- One Function

35. PRINCIPLES OF TENDON TRANSFERS Prevention and Correction of Contracture Tissue Equilibrium Adequate Strength Amplitude of Motion Straight Line of Pull One Tendon- One Function - If a muscle is inserted into two tendons having separate functions, force and amplitude will dissipated and less effective - At the very least if it is done, extrusion of the two should be the same

36. PRINCIPLES OF TENDON TRANSFERS Prevention and Correction of Contracture Tissue Equilibrium Adequate Strength Amplitude of Motion Straight Line of Pull One Tendon- One Function Synergism

37. PRINCIPLES OF TENDON TRANSFERS Prevention and Correction of Contracture Tissue Equilibrium Adequate Strength Amplitude of Motion Straight Line of Pull One Tendon- One Function Synergism -Synergy of activity of the donor and “recipient” muscles and/or tendons is generally considered advantageous should be selected if at all possible - Eg:Wrist extension usually occurs with finger flexion, and both sets of muscles are activated concurrently by the brain when gripping

38. PRINCIPLES OF TENDON TRANSFERS Prevention and Correction of Contracture Tissue Equilibrium Adequate Strength Amplitude of Motion Straight Line of Pull One Tendon- One Function Synergism Expendable Donor

39. PRINCIPLES OF TENDON TRANSFERS Prevention and Correction of Contracture Tissue Equilibrium Adequate Strength Amplitude of Motion Straight Line of Pull One Tendon- One Function Synergism Expendable Donor -Transfer of a musculotendinous unit must not result in unacceptable loss of function. Eg -One should not transfer both the ECRL and ECRB to restore new functions because active wrist extension would be lost

40. Timing of tendon transfres Early transfers to restore wrist, finger, and thumb extension when there was a poor prognosis for the radial nerve injury and its repair. Ignoring the nerve and proceeding directly to the tendon transfers if there was a nerve defect of more than 4 cm, a large wound or extensive scarring, or skin loss over the nerve However, if 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 Would only proceed to tendon transfers if it was clear that inadequate muscle reinnervation had occurred by both clinical and electrodiagnostic criteria

41. REQUIREMENTS IN PATIENTS WITH RADIAL NERVE PALSY A patient with an irreparable radial nerve palsy needs to be provided (1) wrist extension (2) finger (MP joint) extension (3) a combination of thumb extension and abduction “The motors available for transfer for a patient with isolated radial nerve palsy include all the extrinsic muscles innervated by the median and ulnar nerves’’ Unless patient has a painful neuroma- sensory part of the radial nerve usually can be ignored

42. HISTORICAL REVIEW Sir Robert Jones, 1st Baronet, KBE, CB, TD, FRCS  Father of Modern Orthopaedics Sir Robert Jones proposition not universally accepted. Only part that is accepted and in practise is PT to Wrist Extensors Germans were influenced by Perthes , who advocated tendodesis or arthrodesis but later proved obsolete Zachary in 1946 illustrated that it is desirable to leave atleast one wrist flexor intact; PL alone for stabilisation is not enough Boyes in 1960 reasoned that FCU is more important to preserve than FCR because normal axis of wrist motion is from dorso -radial to radio-ulnar

43. TENDON TRANSFERS 1. FCU Transfer 2. Superficialis Transfer 3. FCR Transfer

44. FCU TRANSFER Incision : 3 as shown in Figure 1 st incision: - Longitudinally over the FCU tendon in the distal half of forearm; Distal end is J shaped to reach PL tendon -FCU Freed up and Transected proximal to pisiform 2 nd Incision: -2 inches below M. Epicondyle towards Lister’s 3 rd Incision: -Begins volar radial; passes dorsally in the insertion region of PT; then angles back towards Lister’s -PT Freed up and Transected

45. - PT muscle–tendon unit must be freed up proximally to divide adhesions to improve subsequent excursion -The PT muscle and tendon are passed subcutaneously around the radial border of the forearm, superficial to the BR and ECRL, to be inserted into the ECRB just distal to its musculotendinous junction 1. PT to ECRB

46. 2. FCU TO EDC -A tendon passer or large Kelly clamp is passed from dorsal wound (third incision) subcutaneously, and the tendon of the FCU is pulled -FCU muscle belly is further trimmed if there is still excessive muscle overlying the ulnar border of the forearm -End-to-side juncture is shown hereThis allows a more direct line of pull

47. 3. PL to rerouted EPL -The EPL muscle is identified in the dorsal wound; divided at its musculotendinous junction and passed across the anatomic snuffbox toward the palmar aspect of the wrist -The PL tendon is transected at the wrist, and muscle–tendon unit is freed up proximally until a straight line of pull is achieved The PL tendon is delivered into the dorsal wound in the region of the snuffbox .

48. TENSION • FCU under maximum tensionTension • Wrist in neutral (0 degrees) • MP joints in neutral

49. Post-op management In the operating room , a long arm splint that immobilizes -Forearm in 15 to 30 degrees of pronation -Wrist in approximately 45 degrees of extension -MP joints in slight (10–15 degrees) flexion -Thumb in maximum extension and abduction -PIP joints of the fingers are left free 10 to 14 days postop The splint and sutures are removed, long arm cast applied 4 weeks postop The cast is removed and a short arm splint is applied to hold wrist, fingers, and thumb This should be worn for 2 weeks, though is removed intermittently for exercise.

50. A planned exercise program -Begun at week 4 -Good control of function by 3 months -Maximum recovery by 6 months

51. Potential problems Excessive Radial Deviation Removing FCU(the only remaining ulnar deviator) Contra-indicated in isolated PIN palsy -Altering the insertion- Centeralisation -Suturing to ECRB after resecting distal 2 to 3 cms -Reinserting ECRL in the base of third and fourth metacarpals 2. Absence of PL -Including EPL into FCU to EDC transfer -BR after extensive freeing up - Boye’s Superficialis transfer

52. SUPERFICIALIS TRANSFER PT to ECRL and ECRB FDS iii to EDC FDS iv to EIP and EPL FCR to APL and EPB Important Steps Muscle bellies of transferred FDS muscles are passed through interosseous space to prevent adhesions Tension Wrist : 20 degrees extension Fingers and Thumb held in a fist FDS under maximum tension

53. FCR TRANSFER PT to ECRB FCR to EDC PL to rerouted EPL Important Steps : Divide FCR near its insertion and pass subcutaneously Divide EDC tendons just proximal to retinaculum and reposition stumps superficial to retinaculum Tension: • Wrist in neutral (0 degrees) • MP joints in neutral (0 degrees) • FCR under maximum tension

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