CUBITAL TUNNEL SYNDROME: Diagnosis and Management Michael Zlowodzki MD University of Minnesota Department of Orthopaedic Surgery

OUTLINE Anatomy Epidemiology Clinical exam Treatment options Submuscular transposition technique OITE relevant stuff Statistics: Effect size Meta-analysis

EPIDEMIOLOGY Ulnar nerve compression at the elbow: Second most common compression neuropathy of the upper limb Incidence: 25 per 100000 person years USA: 75000 cases annually World-wide: 1.5 million cases

HISTORY Treated surgically for the first time in 1816 by Henry Early

TREATMENT OPTIONS Simple decompression Medial epicondylectomy Ulnar nerve transposition Subcutaneous Intramuscular Submuscular ULNAR NERVE TRANSPOSITION IS THE MOST COMMON PROCEDURE (Dutch survey data)

PRO SIMPLE DECOMPRESSION Preserves blood supply to ulnar nerve Shorter operation Earlier recovery because anatomical location of ulnar nerve is preserved

PRO TRANSPOSITION Only transposition addresses the dynamic compression of the ulnar nerve seen with elbow flexion

ANATOMY Osbornes ligament: Struthers arcade Between FCU heads where ulnar nerve enters forearm Struthers arcade Fascial thickening in medial upper arm intermuscular septum where ulnar nerve enters dorsal compartment

OSBORNE’S LIGAMENT

ARCADE OF STRUTHERS INCIDENCE: 13.5%

STRUTHER’S LIGAMENT MEDIAN nerve passes between ligament and humerus and can be compressed Incidence: 1% Can be associated with bony spur visible on xrays Don’t confuse with Struther’s Arcade!!!

CLINICAL SIGNS Sensory changes in ulnar nerve distribution (little+ring finger) Intrinsic weakness (not always!) Tinel’s sign at medial elbow Elbow flexion test (3 min @ 120° flexion reproduces symptoms) Wartenberg’s sign Fromment’s sign

AUTONOMOUS ULNAR NERVE SENSORY ZONE

Most sensitive: 30 sec of elbow flexion in conjunction with direct pressure at ulnar nerve 93% SENSITIVITY

Wartenberg’s Sign Ulnar abduction of 5th digit due to due to intrinsic weakness and unopposed abduction by extensor digiti minimi (because of it’s slightly ulnar insertion) Don’t confuse with Wartenberg’s syndrome!

Wartenberg’s Syndrome Sensory RADIAL nerve neuritis Pain in radial distal forearm

FROMMENT SIGN Can’t adduct thumb (ulnar nerve) Flexes thumb IP joint instead (median nerve)

Martin-Gruber Anastomosis Median to ulnar nerve anastomosis Mainly motor fibers Incidence: 17% Therefore intrinsic weakness not always present in cubital tunnel syndrome

Is Nerve Compression or Traction causing Symptoms?

BASIC SCIENCE CLINICAL DATA

CROSS SECTION

Is Nerve Compression or Traction causing Symptoms? Gelberman RH et al. Changes in interstitial pressure and cross-sectional area of the cubital tunnel and of the ulnar nerve with flexion of the elbow. JBJS Am. 1998

TRACTION IS THE PROBLEM - Simple decompression insufficient

LITERATURE REVIEW A systematic review based on non-randomized data n=3024 patients in 60 studies Potential selection bias: patients with less severe symptoms were treated more frequently with simple decompression Bartels RH, Menovsky T, Van Overbeeke JJ, Verhagen WI. Surgical management of ulnar nerve compression at the elbow: an analysis of the literature. J Neurosurg. 1998;89:722-7.

BETTER RESULTS WITH SIMPLE DECOPMPRESSION COMPRESSION IS THE PROBLEM

BASIC SCIENCE: Traction is the problem BASIC SCIENCE: Traction is the problem! CLINICAL DATA: Compression is the problem!

Less biased estimate of the true treatment effects PURPOSE OF THIS STUDY Less biased estimate of the true treatment effects Randomized data only

No previous elbow trauma No previous surgery ELIGIBILITY CRITERIA No previous elbow trauma No previous surgery All patients failed initial conservative treatment Only randomized trials were included to limit selection bias

DIAGNOSIS CONFIRMED BY EMG IN ALL CASES

STUDY IDENTIFICATION INDPENDENT SEARCH BY 2 OF US Medline Embase Cochrane Database of Systematic Reviews Cochrane Central Register of Controlled Trials CINAHL Annual meeting archives: Academy of Orthopaedic Surgeons (2004-2006) American Association of Plastic Surgeons (2005-2006) American Association of Neurological Surgeons (2001-2006) American Society for Surgery of the Hand (2001-2006) INDPENDENT SEARCH BY 2 OF US

METHODS Duplicate assessment of methodological quality (Detsky scale) Duplicate data abstraction independently by two of us Assessment of heterogeneity (Hedges & Olkin) Assessment of publication bias Random effects model for pooling data Outcome parameters converted to effect sizes

Post-op EMG Post clinical score OUTCOME PARAMETER McGowan score Bishop score Medical Research Council score

RESULTS

Screening

STUDY CHARACTERISTICS 4 studies identified 2 studies: simple decompression versus submuscular ulnar nerve transposition (n=117) 2 studies: simple decompression versus subcutaneous ulnar nerve transposition (n=218). Total of 335 randomized patients, 327 of whom were followed up (98%). Sample sizes: 47 to 152 Average age: 51 years 65% males

AUTHORS OF IDENTIFIED STUDIES WERE CONTACTED AND ALL PROVIDED THE RAW DATA

SEVERITY OF SYMPTOMS Majority of patients with moderate or severe symptoms Dellon grade (II or III) Pre-operative Medical Research Council grade (avg. of 4.3 on 1-7 scale) Pre-op EMG (avg. NCV of 35 m/s)

Pre-op Nerve Conduction Velocity Post-op Nerve Conduction Velocity

Post-op Clinical Scores: Effect Size

WHAT IS EFFECT SIZE? A number that expresses a difference between two groups as a multitude of standard deviations

Mild: 0.2 Moderate: 0.5 Large: 0.8 COHEN’s EFFECT SIZE CLINICAL SCORE EFFECT SIZE BETWEEN AT AND SD: -0.04 (-0.36 to 0.28)

CONCLUSIONS No difference in motor nerve conduction velocities and clinical outcome scores Confidence intervals around the points of estimate are narrow probably excluding clinically meaningful differences

SINCE ULNAR NERVE TRANSPOSITION IS THE MORE INVASIVE OF THE TWO PROCEDURES, THIS DATA SUPPORTS THE USE OF SIMPLE DECOMPRESSION OF THE ULNAR NERVE.

TREND TOWARDS BETTER RESULTS WITH TRANSPOSITION BEWARE: INCLUDES NON-RANDOMIZED DATA!!!

MEDIAL EPICONDYLECTOMY

NO MAJOR DIFFERENCES, BUT HIGHER SATISFACTION AFTER MEDIAL EPICONDYLECOMY

BOTTOMLINE: NO CONSENSUS ON BEST TREATMENT

ANTERIOR TRANSPOSITION INDICATIONS Prior injury to elbow Revision surgery Intra-operative ulnar nerve subluxation

SUBMUSCULAR / INTRAMUSCULAR TRANSPOSITION TECHNIQUE

OITE Reminder: Struther’s Arcade Wartenberg’s sign Struther’s ligament Wartenberg syndrome ULNAR NERVE MEDIAN NERVE RADIAL NERVE

CASE ID: 19

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