Direct current electrical stimulation of acupuncture needles for peripheral nerve regeneration: an exploratory case series.

OBJECTIVE: To examine the therapeutic effect of a novel therapeutic method based on electroacupuncture with intermittent direct current (DCEA) and associated adverse events in patients with peripheral nerve damage and a poor clinical prognosis. METHODS: In seven older patients with peripheral nerve damage (neurapraxia 2, axonotmesis 4, neuromesis 1), an acupuncture needle connected to an anode electrode was inserted proximal to the site of the injury along the route of the nerve, while the cathode electrode was inserted into the innervated muscle, and DCEA was performed (100 Hz for 20 min, weekly). Muscular paralysis was evaluated weekly with manual muscle testing, the active range of motion of joints related to the muscular paralysis and, when necessary, needle electromyography. Adverse events were also recorded during the course of the treatment. RESULTS: Complete functional recovery was observed in the two cases with neurapraxia and two with axonotmesis, while one axonotmesis case achieved improvement and the other showed reinnervation potential without functional recovery. No improvement was observed in the neurotmesis case. Pigmentation of the skin where the anode needle was inserted occurred in three cases. Although there was no definite causal link, one case showed excessive formation and resorption of bone in the area close to the cathode needle site. DISCUSSION: Accelerated nerve regeneration caused by DCEA may contribute to recovery. The skin pigmentation and callus formation suggest that the shape of the anode electrode, current intensity and other factors should be examined to establish a safer treatment method.