Brief post-surgical electrical stimulation accelerates axon regeneration and muscle reinnervation without affecting the functional measures in carpal tunnel syndrome patients

Exp Neurol. 2010 May;223(1):192-202. doi: 10.1016/j.expneurol.2009.09.020. Epub 2009 Oct 1.

Abstract

Electrical stimulation (ES) of injured peripheral nerves accelerates axonal regeneration in laboratory animals. However, clinical applicability of this intervention has never been investigated in human subjects. The aim of this pilot study was to determine the effect of ES on axonal regeneration after surgery in patients with median nerve compression in the carpal tunnel causing marked motor axonal loss. A randomized control trial was conducted to provide proof of principle for ES-induced acceleration of axon regeneration in human patients. Carpel tunnel release surgery (CTRS) was performed and in the stimulation group of patients, stainless steel electrode wires placed alongside the median nerve proximal to the surgical decompression site for immediate 1 h 20 Hz bipolar ES. Subjects were followed for a year at regular intervals. Axonal regeneration was quantified using motor unit number estimation (MUNE) and sensory and motor nerve conduction studies. Purdue Pegboard Test, Semmes Weinstein Monofilaments, and Levine's Self-Assessment Questionnaire were used to assess functional recovery. The stimulation group had significant axonal regeneration 6-8 months after the CTRS when the MUNE increased to 290+/-140 (mean+/-SD) motor units (MU) from 150+/-62 MU at baseline (p<0.05). In comparison, MUNE did not significantly improve in the control group (p>0.2). Terminal motor latency significantly accelerated in the stimulation group but not the control group (p>0.1). Sensory nerve conduction values significantly improved in the stimulation group earlier than the controls. Other outcome measures showed a significant improvement in both patient groups. We conclude that brief low frequency ES accelerates axonal regeneration and target reinnervation in humans.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials / physiology
  • Adult
  • Aged
  • Carpal Tunnel Syndrome* / pathology
  • Carpal Tunnel Syndrome* / physiopathology
  • Carpal Tunnel Syndrome* / surgery
  • Electric Stimulation Therapy / methods*
  • Electromyography / methods
  • Female
  • Humans
  • Male
  • Median Nerve / physiopathology
  • Middle Aged
  • Motor Neurons / physiology
  • Muscle, Skeletal / physiopathology
  • Nerve Regeneration / physiology*
  • Neural Conduction / physiology
  • Reaction Time / physiology
  • Recovery of Function / physiology*
  • Surveys and Questionnaires
  • Treatment Outcome