Ulnar nerve compression Michael Maru Orthopaedic Postgraduate Teaching 23/04/07

Introduction Second most common entrapment neuropathy M >F 5:1 Frequently bilateral Before 1959,it was thought to be posttraumatic ulnar palsy After 1959, Osborne called it tardy ulnar palsy referring to idiopathic ulnar neuritis Feindel & Stafford in 1973 coined the term cubital tunnel syndrome (CTS) Commonest cause of ulnar nerve compression is CTS

Relevant anatomy Terminal portion of medial cord ( C8, T1) Supplied by post. ulnar recurrent artery Forearm : FCU, FDP, cutaneous ulnar 4/5th digits Hand: All motor Palmaris brevis Interossei Lumbricals (3rd & 4th) Flexor pollicis brevis Adductor pollicis Hypothenar muscles

Branches: all distal to elbow

Anatomy Sunderland 1987; “Double crush” concept Described internal topography of ulnar nerve Sensory and intrinsics fibres superficial Motor fibres to FCU & FDP are deeply located Hence weakness of FCU/FDP not typically seen in ulnar nerve neuropathy Sunderland S: Nerves and nerve injuries . 2nd ed. New York, NY: Churchhill Livingston; 1987: 728-74 “Double crush” concept Proximal compression of nerve trunk may increase vulnerability to distal compression This is due to disruption of axonal transport

Sites of compression Elbow Arcade of Struthers Medial epicondyle Olecranon groove Cubital tunnel Anomalous anconeus Flexor pronator aponeurosis

Sites cont… Guyons canal: Ulnar tunnel syndrome Tunnel enclosed by piso-hamate ligament Commonly due to ganglion cyst, tumour, aneurysm or fractured hook of hamate Involvement of dorsal sensory branch indicates compression proximal to Guyon’s canal

Risk factors Trauma; Bony deformities; Soft tissue masses Acute, chronic or repetitive Anaesthesia and bed-ridden patients Pressure with flexed elbow (occupational) Bony deformities; Arthritis (RA) Shallow groove Valgus deformity Soft tissue masses Ulnar nerve prolapse Alcoholism Diabetes

Clinical presentation Paraesthesia; ring and little finger (night) Pain ( Elbow) Weakness of grip, dropping objects Clawing More in distal lesions “Ulnar paradox” Hyperextension of MCPJ (lumbricals) Flexion of IPJ (interossei) Intrinsic muscle wasting

Classification McGowan; Types 1: recent, mild, intermittent dysaethesia II: persistent dysaethesia, early motor loss III: Marked atrophy and weakness McGowan AJ. The results of transposition of the ulnar nerve for traumatic ulnar neuritis. J Bone Joint Surg Br, 1950;32: 293-301.

Diagnosis History & Examination Special provocation tests Ask & look for risk factors Neurological examination of upper limb Special provocation tests Elbow flexion test: supinate, flex elbow and hyperextend wrist Froments sign : weak adductor pollicis Wartenburg sign: little finger adopts abducted posture “Making a wish” sign: unable to cross index over middle Tinels sign: tapping along the ulnar groove causes tingling to ring and little fingers ( +ve in 24% normal popu)

Differential diagnosis Cervical root lesion/myelopathy Neck & Arm pain, UMN signs Thoracic outlet syndrome Vascular anomalies Fatigue with arm overhead Brachial plexus abnormalities Involvement of other nerves

Investigations Radiographs Nerve conduction studies Electromyography Conduction velocities < 50m/s Identify site of compression Electromyography Axonal degeneration MRI Ultrasound scan

Management Conservative Indicated if paraesthesia is transient Patient education about posture NSAIDs for nerve irritation Physiotherapy Elbow extension splints Treatment of ulnar nerve palsy at the elbow with a night splint Seror-P. Laboratoire d'Electromyographie, JBJS-Br. 1993 Mar. 75(2). P 322-7. 22 patients treated with night splint preventing elbow flexion beyond 60 degrees. Improvement of symptoms in every patient including 3 who had failed surgical decompression! Conclu: Nocturnal elbow flexion aggravates symptoms

Operative management Indications Options Failure of conservative methods Persistent paraesthesia Progressive symptoms especially motor Options Decompression in-situ Decompression with transposition

Decompression in-situ Incision 8cm proximal and 6 cm distal to medial epicondyle Osborne ligament incised to open tunnel Open or endoscopic May be combined with medial epicondylectomy

Decompression with transposition May be indicated in: Recurrence of symptoms after simple neurolysis Acute fracture ORIF ( prominent metalware) Elbow arthroplasty (scarring) Ulnar nerve repair Cubital valgus Arthritis with osteophytes formation Recurrent dislocation of nerve

Decompression with transposition Anterior transposition to lengthen nerve and decrease tension Can be submuscular, intra-muscular or subcutaneous Held using fascio-dermal sling or suture

Transposition or not? Cochrane Review; 5 RCTs, same conclusion Simple decompression or subcutaneous anterior transposition of the ulnar nerve for cubital tunnel syndrome NABHAN A et al ; The Journal of hand surgery 2005, vol. 30, pp. 521-524 Prospective randomised study; 66 patients, 32 had simple decompression, 34 had transposition. At 9 months , no significant difference in pain, sensory or motor deficits. Recommended simple decompression Randomized, prospective study comparing ulnar neurolysis in situ with submuscular transposition Biggs M, Curtis J; Neurosurgery 2006, Vol 58, issue 2, pg 296-304 RCT, 44 patients, 21 had neurolysis, 23 had transposition. Both procedures equally effective in objective neurological improvement. However, higher wound complications.in transposition group.Conclusion; Neurolysis in situ for idiopathic symptomatic ulnar nerve compression

Endoscopic or open? Endoscopic method becoming popular Thought to be less invasive, quick rehab No reported RCT Tsu-Min Tsai et al (1999) 85 elbows in 76 patients F/U of 32 months 42% excellent, 45% good, 11% fair,2% poor Tsai TM, Chen IC, Majd ME: Cubital tunnel release with endoscopic assistance: results of a new technique. J Hand Surg [Am] 1999 Jan; 24(1): 21-9

Decompression at the wrist Zigzag incision Pisohamate ligament opened Identify and remove the cause Usually ganglion cyst (Sedon) beware aneurysm! Hence the need for appropriate investigation before operating

Conclusion Commonest site of ulnar nerve compression is at the cubital tunnel in the elbow Decompression in-situ (neurolysis) is recommended for idiopathic ulnar nerve neuropathy Transposition should be considered in recurrent cases, arthritis and cubital valgus Endoscopic release is the future trend.

Thank you ?