Ann Rehabil Med.  2019 Jun;43(3):341-346. 10.5535/arm.2019.43.3.341.

Palmar Digital Neuropathy With Anatomical Variation of Median Nerve: Usefulness of Orthodromic Technique: A Case Report

• Noh JS
• Park JW
• Kwon HK

• KMID: 2453925
• DOI: http://doi.org/10.5535/arm.2019.43.3.341

Abstract

Anatomic variation of palmar digital nerve pathways were reported in several cases. Selective exploration of palmar digital nerves with a nerve conduction study has been challenging, because of technical issues. We report a patient who received bilateral carpal tunnel release operation, complaining of a tingling sensation, and hypoesthesia on the middle and ring fingers. An electrodiagnostic study revealed a sensory neuropathy of palmar digital nerve of the left median nerve, supplying the ulnar side of the middle finger, and radial side of the ring finger. She underwent re-operation of open left carpal tunnel release, and a branching site of common digital nerves of the median nerve was identified not at the palm, but at a far proximal site around the distal wrist crease. Usefulness of an orthodromic sensory conduction study was clarified to eliminate volume conducted response or co-activation of nearby nerves in the patient with selective involvement of palmar digital nerve.

Keyword

Median nerve; Electrodiagnosis; Carpal tunnel syndrome; Median neuropathy

MeSH Terms

Anatomic Variation
Carpal Tunnel Syndrome
Electrodiagnosis
Fingers
Humans
Hypesthesia
Median Nerve*
Median Neuropathy
Neural Conduction
Sensation
Wrist

Figure

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  Fig. 1. Orthodromic sensory conduction study of palmar digital nerve, supplying the ulnar side of the middle finger (A) and radial side of the ring finger (B).

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  Fig. 2. Orthodromic median sensory response was not obtainable with the left ulnar side of III digit and the radial side of IV digit stimulations, in preoperative study (A and C), but obtainable with low amplitude postoperatively (B and D).

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  Fig. 3. Divergence of common palmar digital nerves (arrowhead) was found, around a distal wrist crease level. A traumatic neuroma (0.5×0.5 cm, arrow) was identified, proximal to a diverging site (A). Neuroma excision and microscope-assisted to direct the end-to-end neurorrhaphy were performed (B).

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