Cubital tunnel syndrome is the second most common compression neuropathy. In severe cases, functional recovery, even with surgery, is often poor. Therefore, alternative adjunct treatments capable of increasing the speed of nerve regeneration are much needed.

The effect of brief conditioning electrical stimulation on nerve regeneration has been showed to be efficacy in animal studies. In this double-blind, randomized, controlled study, the investigators will compare the physiological and functional improvements post surgery compared with the controls who received surgery alone. Because electrical stimulation is reasonably well-tolerated and the treatment only takes an hour, it is a potentially feasible clinical tool for patients with severe nerve injury.

Inclusion Criteria:

1. Patients aged >18 yr,
2. If signs and symptoms of severe CuTS (ie, McGowan-Goldberg grade 3) were observed,
3. If needle EMG examination showed evidence of chronic motor axonal loss and reduced recruitment in the ulnar-innervated intrinsic hand muscles, and
4. If electrophysiologic evidence of severe motor axonal loss with motor unit number estimation (MUNE) greater than 2 standard deviations below the normative mean.

Exclusion Criteria:

1) Patients were excluded if they had concurrent nerve injury, prior surgery for CuTS or coexisting neurologic conditions