Median nerve injuries and mangement

anatomy of median nerve,course in arm and struthers ligament, branches in the forearm, carpal tunnel and course in hand, high and low median nerve injuries, principles of surgical management, pronator teres syndrome, anterior interosseous nerve syndrome, open and endoscopic carpal tunnel release

1. Median Nerve Injuries Dr SD Sanyal

2. Anatomy Mixed nerve (contain motor & sensory fibers). Root value: C 5,6,7,8 & T1 Runs in the median plane of the forearm , so its called median nerve

3. Anatomy Arises in the axilla by joining: 1) Lat Cord of the brachial plexus 2) Med Cord of the brachial plexus

4. Anatomy: Axilla After being from Lateral Cord Medial Cord of brachial plexus Runs on the lateral aspect of Axillary artery

5. Anatomy: Arm Continues to run lateral to the brachial artery till the mid-arm Crosses the artery anteriorly and passes anterior to the elbow joint into forearm

6. Anatomy: Forearm Enters to the forearm b/w two heads of pronator teres . Runs deep to the fibrous arch of FDS , in proximal 1/3 rd Mid forearm it descends b/w FDS and FDP About 5 cm above wrist , it comes to lie on the lateral side of the FDS , becomes superficial just above wrist

7. Anatomy: Hand Passes deep to the flexor retinaculum and enters the Hand Muscular braches supply muscles of Thenar eminence: - abductor pollicis brevis - opponens pollicis - flexor pollicis brevis

8. Anatomy: Hand Divides into 4 to 5 palmar digital branches supplying lateral three and half digit and their nail beds Motor braches to the first and second lumbrical muscles

9. Other branches Articular branches: supply the proximal radio- ulnar joint Palmar cutaneous branch: supplies skin over thenar eminence

10. Injuries High Low

11. High Median Nerve injuries Injury proximal to the elbow Due to forearm fractures or elbow dislocation Stab injuries and GSW’s Paralysis of all the muscles supplied by the median nerve in the forearm and hand

12. Low Median Nerve Injuries Injury in the distal third of the forearm Sparing of the forearm muscles Muscles of the hand paralysed Anaesthesia over the median nerve distribution in the hand Thenar eminence is wasted and thumb abduction and opposition are weak Sensation lost over the radial three and half digits and trophic changes may seen

13. Examination Flexor pollicis longus : Tested by holding thumb at its base and patient asked to flex the terminal phalanx

14. Examination Flexor digitorum superficialis & profundus ( Oscher’s clasping test) - Patient is asked to clasp the hands , the index finger of affected side fails to flex

15. Examination Flexor Carpi radialis : Hand deviates to the ulnar side when flexed against resistance

16. Examination Muscles of Thenar eminance : - abductor pollicis brevis (Pen test) - hand laid flat on the table - pen held above the palm and the patient is asked to touch the pen with his thumb

17. Examination opponens pollicis : brings the tip of the thumb towards the tips of other fingers

18. Opponens pollices

19. Benedict Sign

20. Klien Nioh / OK Sign

21. Ape Thumb

22. Principles of Surgical Management Direct Injury: Nerve repair Compression neuropathies: Decompression Long standing cases: Tendon transfers Low Median Nerve: - Re-routing of ring/ middle finger superficial flexor around FCU to APB to aid thumb opposition High Median Nerve: - Suturing of profundus tendons to ring and small finger tendons for restoration of IP jt movts - ECU re-routing and attachment to dorsal radius/ Transfer of biceps insertion from medial to lat radius for weak forearm pronation

23. Median nerve Compression Syndromes Carpal Tunnel Pronator Interosseous

24. Carpal Tunnel Syndrome Compressive neuropathy as the nerve passes through the Carpal Tunnel Causes: - Idiopathic : Most common - Inflammatory : Rheumatoid Arthritis : Wrist osteoarthritis - Post traumatic : Bone thickening - Endocrine : Myxoedema : Acromegaly - Pregnancy - Gout - Repetitive wrist movts : Typists & Computer users

25. Carpal Tunnel

26. Symptoms Hand and wrist Pain Paraesthesia Hypoaesthsia Sparing of Palmar cutaneous branch supply Patient wakes at night with burning or aching pain and shakes the hand to obtain relief and restore sensation Aggravated by elevation of hand Thenar atrophy and weakness of thumb opposition and abduction may develop late

27. Diagnosis History Clinical examination: - Thenar wasting - Phalen’s sign - Tinel’s sign - Carpal compression test Electro Diagnostic Studies: - Very reliable for evaluation - Atypical cases may be present

28. Thenar atrophy

29. Tinel’s Sign

30. Carpal Compression test/ Durkan’s test

31. Management Splinting – prevents wrist flexion Corticosteroid/anesthetic injection Surgical decompression:Division of the transverse carpal ligament - Open - Endoscopic

32. Complications Injury to palmar cutaneous /recurrent motor branch of the median nerve Hypertrophic scarring Hematoma/Arterial injury Pillar pain

33. Pronator teres syndrome High Compression neuropathy It is rare compared to CTS and AIS Misnomer  Proximal forearm median nerve compression

34. Symptoms & signs Symptoms are similar to those of carpal tunnel syndrome Sensory disturbances - Thumb & Index > Middle finger Night pain is unusual and forearm pain is more common Hand numbness on gripping Phalen’s test negative Double crush phenomena Symptoms provoked by resisted elbow flexion with forearm supinated ( tightening of bicipital aponeurosis ) By resisted forearm pronation with the elbow extended ( pronator tension )

35. Management No relief with steroids Surgical decompression

36. Anterior Interosseous Syndrome Damage to the Anterior Interosseous Nerve Pain in the forearm Weakness of the gripping movement of the thumb and index finger( unable to make ok sign ) Causes: - Injury to elbow - Injury during open/closed reduction

37. Management Corticosteroids Surgery: - Resection/detachment of deep head of PT

38. Thank You