Radial nerve entrapment

radial nerve entrapment, diagnosis, treatment, muscle examination in detail

1. RADIAL NERVE ENTRAPMENT NEUROPATHY Presented by : Dr Yash Oza Moderator : Dr Pradip Patil

2. Radial Nerve e Largest bra n ch of the brachial plexus Arises from the posterior cord of the brachial plexus (C5–T1) Mixed nerve Anatomy

3. Course of Radial Nerve The Axilla The Axilla to the Spiral Groove The Spiral Groove to the Supinator Muscle Branches The Posterior Interosseous Nerve The Superficial Sensory Radial Nerve

4. The Axilla Radial nerve in the distal axilla. The radial nerve lies superficial to three muscles ( from proximal to distal): the subscapularis the latissimus dorsi tendon the teres major The radial nerve enters the arm anterior to the long head of the triceps . It soon dives into a cleft between the long triceps head and the medial triceps head . Within this cleft, the nerve runs toward the spiral groove.

5. The Axilla to the Spiral Groove The radial nerve passes down the spiral groove between the origins of the lateral and medial heads of the triceps. It remains in contact with the humerus and is covered by the lateral head of the triceps. Then it pierces the lateral intermuscular septum, about halfway down the arm.

6. The Spiral Groove to the Supinator Muscle Upon entering the flexor compartment at midarmlevel , the radial nerve runs under three muscles, which sequentially arcade over the nerve . This anatomical arrangement has been referred to as the radial tunnel . ECRB loops over it; that may predispose the radial nerve to irritation . Distal to the elbow joint, the radial nerve bifurcates into the, posterior interosseous and superficial sensory radial nerves. And enter supinator muscle.

7. The supinator has a deep and a superficial head. The superficial head forms a pocket, into which the posterior interosseous nerve descends. The edge of this pocket can be fibrous and is termed the arcade of Fröhse . The superficial sensory radial nerve remains superficial to both heads of the supinator.

8. The Posterior Interosseous Nerve After emerging from between the two heads of the supinator muscle, the PIN lies between extensor digitorum communis the abductor pollicis longus . It then ramifies into a large number of unnamed branches, which are often called the cauda equina of the forearm. It gives of muscular branches to following muscle. PIN Deep Group: Abductor Pollicis longus Extensor pollicis longus Extensor pollicis brevis Extensor indicis PIN Superficial Group Extensor carpi Ulnaris Extensor digitorum communis Extensor digiti minimi

9. The Superficial Sensory Radial Nerve It remains deep to the brachioradialis muscle until 2/3 rd of the way down the forearm. In the lower 1/3 rd it becomes superficial when the BR and ECRL form their tendons. Then nerve passes to the dorsal aspect of the wrist, branches upon the dorsolateral aspect of the hand, and remains superficial to the extensor retinaculum. The superficial sensory radial nerve usually has four or more terminal sensory branches. Dorsal digital nerves ECRL Dorsal Radial Sensory BR Nerve 8 cm Radial styloid

10. Lower lateral cutaneous nerve of arm Posterior cutaneous nerve of arm Posterior cutaneous nerve of forearm Dorsal radial sensory nerve dorsum of the hand over the radial two-thirds, the dorsum of the thumb, and the index, middle finger proximal to the distal interphalangeal joint. Cutaneous innervation from radial nerve

11. MOTOR Innervation Of Radial Nerve

12. MOTOR Innervation Of Radial Nerve Radial nerve Innervated muscle Triceps brachii Brachioradialis Extensor carpi radialis longus Extensor carpi radialis brevis

13. Radial nerve Innervated muscle Triceps brachii Brachioradialis Extensor carpi radialis longus Extensor carpi radialis brevis

14. Radial nerve Innervated muscle Triceps brachii Brachioradialis Extensor carpi radialis longus Extensor carpi radialis brevis

15. PIN Supinator Extensor carpi ulnaris Extensor digitorum Extensor digiti minimi Abductor pollicis longus Extensor pollicis longus Extensor pollicis brevis Extensor indicis

16. PIN Supinator Extensor carpi ulnaris Extensor digitorum Extensor digiti minimi Abductor pollicis longus Extensor pollicis longus Extensor pollicis brevis Extensor indicis

17. PIN Supinator Extensor carpi ulnaris Extensor digitorum Extensor digiti minimi Abductor pollicis longus Extensor pollicis longus Extensor pollicis brevis Extensor indicis

18. PIN Supinator Extensor carpi ulnaris Extensor digitorum Extensor digiti minimi Abductor pollicis longus Extensor pollicis longus Extensor pollicis brevis Extensor indicis

19. PIN Supinator Extensor carpi ulnaris Extensor digitorum Extensor digiti minimi Abductor pollicis longus Extensor pollicis longus Extensor pollicis brevis Extensor indicis

20. PIN Supinator Extensor carpi ulnaris Extensor digitorum Extensor digiti minimi Abductor pollicis longus Extensor pollicis longus Extensor pollicis brevis Extensor indicis EPB – Resistance applied at prox phalanx EPL – Resistance applied at distal phalanx

21. PIN Supinator Extensor carpi ulnaris Extensor digitorum Extensor digiti minimi Abductor pollicis longus Extensor pollicis longus Extensor pollicis brevis Extensor indicis

22. Radial Nerve Entrapment Entrapment neuropathies Entrapment neuropathies refer to isolated nerve injury occurring at specific location where a nerve is mechanically constricted in a fibrous/ fibro osseous tunnel Mechanism is : Compression, constriction, angulation or streatching Common cause : External : cast brace, tourniquet Internal : Bony callous, ganglion, tumours , fibrous tissue, normal or abberent muscle Compression may be acute or intermittent or continuous.

23. Pathophysiology of entrapment Nerve is surrounded by loose connective tissue called adventia nevosum – it is regional vascular bundle in nerve circumference Normally, Movement of extremity slightly alters this vascular circulation Stretch or traction beyond certain limit will affect this circulation and obstruction to outflow . Create positive pressure to endoneurium Leading to intrafascicular edema & nerve damage It’s termed as miniature closed compartment syndrome Histologically – segmental demyelination & remyelination seen It is type of a N europraxia

24. General condition that may predispose to Neuropathy DM GB Syndrome Double crush hypothesis – nerves are more susceptible to compression if fibers are damaged proximally Tomoculous Neuropathy – a hereditary pressure sensitive neuropathy . d/t abnormal myelination

25. Radial Entrapment Common site A) Axialla : Crutch palsy – d/t pressure with ill- adjusted crutches whithout proper handgrip Aneurism of axillary vessels B ) Shoulder # - D/L of upper humerus & attempt to their reduction C ) Radial Groove : # shaft Humerus Prolonged application of tourniquet Ill-applied cast Saturday Night Palsy & Honeymoon palsy Excessive callus of an old fracture Infection & Iatrogenic

26. D) B/w Spiral groove & Lat. Epicondyle # Shaft Humerus # Supracondylar humerus # lateral condyle Cubitus vulgus deformity E)Elbow : Dislocation # neck of radius Enlarged burase RA Elbow Radial head excision surgery Radial tunnel syndrome/ PIN syndrome F ) Forearm Cheiralagia Parasthetica / Wartnberg Disease

27. Saturday night palsy : radial nerve compression in the arm resulting from direct pressure against a firm object.  Honeymoon Palsy : When bed partner’s head compresses radial nerve while resting in crook of partner’s arm Radial tunnel syndrome : Entrapment of PIN in in radial tunnel Cheiralagia Parasthetica / Wartnberg Disease: compression of Superficial radial nerve as it emerges b/w ECRL and BR, 8 cm proximal to radial styloid

28. Type Location Motor Sensory Very High Above spiral groove Total Palsy Post Cut.N . of Arm spared High B/w Spiral groove & Lat Epicondyle Triceps spared BR involevd Lower Lat.CN of Arm & Post.CN of Forearm (+/-?) (both emerges from spiral groove) Low At Elbow Elbow, Wrist extensor spared Lost over dorsum of 1 st web space PIN - Elbow, Wrist extensor spared Spared Type of Radial nerve injuries according to location

29. Clinical Features Sign & Symptoms – according to the level of involvement MOTOR : Clumpsiness , weakness, wasting or fasciculation of muscle Paralysis, loss of tone, atrophy, areflexia , insensitivity to compression SENSORY : Numbness, paresthesia, tingling, prickling, burning over affected area AUTONOMIC : Atrophy, ulcer, skin changes, hyperesthesia

30. TINEL SIGN : Gentle percussion by finger hammer from distal to proximal direction along the course of nerve gives transient tingling sensation in distribution of nerve Sensation should persist for several seconds

31. Diagnosis History taking Motor- sensory examination Electrophysiological studies – EMG & NCV CT scan MRI

32. Motor supply

33. Lower lateral cutaneous nerve of arm Posterior cutaneous nerve of arm Posterior cutaneous nerve of forearm Dorsal radial sensory nerve Cutaneous innervation from radial nerve

34. EMG Indicates that the muscle is innervated or not But gives no specific indication as to the level of injury to nerve Denervated muscle show sharp positive consistent waves. This waves will last until the muscle has become reinvervated or fibrotic.

35. NSC In nerve conduction velocity studies there will be slowed conduction time at a specific point along the course of the nerve

36. Use of Electrodiagnostic Testing Documentation of injury Location of insult Severity of injury Recovery pattern Prognosis Objective data for impairment documentation Pathology Selection of optimal muscles for tendon transfer procedure

37. CT scan & MRI Used to identify causative factor & site for nerve compression by an anatomical object. Not always indicated.

38. Treatment Most of entrapment injuries are managed conservatively with good to excellent result. Important function to be regained are Wrist extension Metacarpophalangeal joint extension Thumb Extension

39. SPLINTS NSAIDS Ultrasound Therapy Gradual rehabilitation programme Removal external offending compression Steroid injection Conservative Treatment

40. SPLINTS full passive range of motion in all joints of the wrist and hand and prevention of contractures, including that of the thumb-index wrist drop can be treated successfully by splints Barkhalter has observed that grip strength may be increased by 3 to 5 times by simply stabilizing the wrist with splints Many types of splints have been described & Each patient individual need should be addressed Conservative Treatment

41. EMG studies every 4 week is indicated during conservative treatment If clinical or EMG evidence of recovery ensues within 12 weeks of onset surgical exploration is most likely not indicated

42. When a nerve deficit follows blunt or closed trauma, and no clinical or electrical evidence of regeneration has occurred after an appropriate time, exploration of the nerve is indicated. If no sign of recovery seen after 12 weeks of conservative therapy, Surgical exploration & Neurolysis with release of all possible offending structure is needed Surgical Exploration

43. It provides internal splint. It restores the power quickly and effectively Advantages are: It works as a substitute during nerve regrowth and largely eliminates an external splint Subsequently the transfer aids the newly innervated and weak wrist extensor It continues to act as a substitute in case nerve regeneration is poor or absent Tendon Transplant

44. Tendon transfers work to correct: instability imbalance lack of co-ordination restore function by redistributing remaining muscular forces

45. Tendon transplant in radial nerve palsy needs to be provided with wrist extension. finger (metacarpophalangeal [MP] joint) extension. a combination of thumb extension and abduction.

46. Radial nerve compression syndromes

47. Wartenberg’s syndrome / Cheiralgia paresthetica compression of Superficial radial nerve as it emerges b/w ECRL and BR, 8 cm proximal to radial styloid Dorsal digital nerves ECRL Dorsal Radial Sensory BR Nerve 8 cm Radial styloid

48. isolated pain or paresthesias over the dorsoradial aspect of the hand preceding history of trauma to the area (i.e., handcuffs, forearm fracture) Differentiating Wartenberg’s syndrome from de Quervain’s tenosynovitis A Tinel’s sign over the superficial sensory radial nerve is the most common exam finding Clinical features presence of motor weakness suggests a more proximal site of compression Also seen in patients who use forearms in pronated position for extended periods → in pronation, the tendons of BR and ECRL approximate and may compress the nerve In WS, pain is exacerbated by pronation, while in DQT pain is elicited with changes in thumb and wrist position DQT - normal sensation in the dorso-radial hand DQT - pain on percussion over the 1 st extensor compartment Electrodiagnostic testing is of limited value in Wartenberg’s syndrome

49. Finkelsetein sign Palmar flexion & ulnar deviation increases the sympopms Treatment Removal of encircling structure ( Wristwatch, Handcuff) Local Inj.of steroid Exploration & Neurolysis

50. Posterior interosseous nerve (PIN) syndrome D/t compression of PIN in the radial tunnel Most common causes include: Tumors such as lipomas, ganglia Rheumatoid synovitis Septic arthritis Vasculitis

51. The radial tunnel is a 5 cm space bounded by: Dorsally : capsule of the radiocapitellar joint Volarly : the BR Laterally : the ECRL and ECRB muscles Medially : the biceps tendon and brachialis muscles Within radial tunnel, there are 5 potential sites of compression: fibrous bands to the radiocapitellar joint between the brachialis and BR the recurrent radial vessels ( leash of Henry ) the proximal edge of the ECRB the proximal edge of the Supinator ( arcade of Fröhse ) the distal edge of the Supinator BR arcade of Fröhse Supinator ECRL PIN

52. Diagn o sis loss of finger and thumb extension Weak wrist extension with radial deviation (since ECRL innervation is intact) Intact passive tenodesis effect (rules out extensor tendon rupture) EMG testing is helpful to confirm the diagnosis and monitor motor recovery

53. Radial Tunnel syndrome Similar to PIN syndrome, it is also d/t compression of PIN in the radial tunnel Not considered a true compression neuropathy by some

54. Radial Tunnel Syndrome is a clinical diagnosis Radial Tunnel Syndrome Tenderness over radial tunnel (lateral proximal forearm, 3-4 cm distal to lateral epicondyle over the mobile wad) Pain at ECRB origin with resistance of middle finger extension Pain with resisted forearm supination ↑ Pain on combined elbow extension, forearm pronation, and wrist flexion