Restoring hand function in patients with severe polyneuropathy: the role of electromyography before tendon transfer surgery.

Abstract

Electromyography (EMG) was evaluated as a supplement to clinical examination and biomechanical considerations to optimize forearm donor muscle selection before tendon transfers to 4 functionless hands in 3 patients with slowly progressive polyneuropathies. Two patients had unusually severe Charcot-Marie-Tooth disease; the third patient had idiopathic mononeuropathy multiplex. Standard EMG parameters were used to devise an intuitive muscle grading system, including most importantly interference patterns and motor control, plus motor unit morphology and stability. Given our objective of restoring survivable function despite ongoing polyneuropathy, we found that EMG reveals prognostically important differences among partially denervated candidate muscles that cannot be detected by experienced clinical examiners. Opposition transfer was performed on one hand of each patient. After 39-, 39-, and 51-month follow-up durations, restored opposition was graded as good in these 3 hands. We conclude that EMG provides meaningful guidance in selecting optimal forearm muscles for tendon transfers to hands in the setting of slowly progressive polyneuropathies.