Postsurgical Electrical Stimulation Enhances Recovery Following Surgery for Severe Cubital Tunnel Syndrome: A Double-Blind Randomized Controlled Trial

Abstract

BACKGROUND Patients with severe cubital tunnel syndrome often have poor functional recovery with conventional surgical treatment. Postsurgical electrical stimulation (PES) has been shown to enhance axonal regeneration in animal and human studies. OBJECTIVE To determine if PES following surgery for severe cubital tunnel syndrome would result in better outcomes compared to surgery alone. METHODS Patients with severe cubital tunnel syndrome in this randomized, double-blind, placebo-controlled trial were randomized in a 1:2 ratio to the control or stimulation groups. Control patients received cubital tunnel surgery and sham stimulation, whereas patients in the stimulation group received 1-h of 20 Hz PES following surgery. Patients were assessed by a blinded evaluator annually for 3 yr. The primary outcome was motor unit number estimation (MUNE) and secondary outcomes were grip and key pinch strength and McGowan grade and compound muscle action potential. RESULTS A total of 31 patients were enrolled: 11 received surgery alone and 20 received surgery and PES. Three years following surgery, MUNE was significantly higher in the PES group (176 ± 23, mean + SE) compared to controls (88 ± 11, P < .05). The mean gain in key pinch strength in the PES group was almost 3 times greater than in the controls (P < .05). Similarly, other functional and physiological outcomes showed significantly greater improvements in the PES group. CONCLUSION PES enhanced muscle reinnervation and functional recovery following surgery for severe cubital tunnel syndrome. It may be a clinically useful adjunct to surgery for severe ulnar neuropathy, in which functional recovery with conventional treatment is often suboptimal.

Role of Electrical Stimulation in Peripheral Nerve Regeneration: A Systematic Review

“…In one RCT with 3 years of follow-up on 31 patients with ulnar nerve injury of grade 3 on the McGowan- Goldberg grading system, 35% of patients who underwent ES attained grade 1 and 40% attained grade 2 when compared with controls, in which 25% attained grade 1 and 25% attained grade 2 ( P < 0.05). 24 The same study reported on grip strength, which improved significantly for cases from the first year onward ( P < 0.001) but not for control even at 3 years ( P = 0.08). Minimal clinical importance difference in grip strength was 5.9 kg.…”

“…Key pinch was also significantly improved for cases ( P < 0.001), and it was reported to be three times that of control, who failed to show a statistically significant improvement in pinch strength at any follow-up ( P > 0.1). 24 …”

“…Wong 15 Power 24 Gordon 22 Piccinini 18 Random measured by EMG was not significantly improved with ES; the authors attributed their contradicting findings to their stimulation parameters (1 Hz, 0.5 h, intensity set to 0.5 mA above lowest intensity needed to produce contraction, using Echo Companion device)‚ as opposed to the parameters used by the other RCTs 15,24 (20 Hz, 1 h, intensity set to tolerance limit <30 V, using Grass SD9 device). Gordon et al 24 and Power et al 24 have reported improvement in motor unit number estimation after ES; in Gordon's study on patients with carpal tunnel syndrome, motor unit number estimation increased after 3 months (from 150 ± 62 MU to 290 ± 140 MU) and was comparable to healthy subjects by 12 months, an effect that was not seen in controls. 22 In the other study on patients with cubital tunnel syndrome, ES resulted in a significant increase in motor unit number estimation (107 ± 11) when compared with controls (78 ± 6) (P < 0.05) at 1 and 3 years, and stimulated patients had more than double the number of motor units when compared with controls (178 ± 11 versus 88 ± 18; P < 0.05) by 3 years.…”

An ultrasound-guided percutaneous nerve stimulation regimen based on finite element modeling for median nerve rupture

“…The denervation of target skeletal muscles occurs following PNI, showing muscle weakness. Grip strength need activate extrinsic and intrinsic hand muscles, of which the forearm peripheral nerve-innervated muscles are a major contributor (Power et al, 2020). Schreuders et al found that the strength will decrease 32% than normal people when median nerve is blocked (Schreuders et al, 2000;Wachter et al, 2018a).…”

Peripheral Nerve Regeneration and Muscle Reinnervation

“…The majority of human nerve injuries, resulting from vehicle accidents, recreational activities and iatrogenic injuries during surgeries, occur in the upper extremity ( Figure 3A) [42]. Seminal studies in rodents in the Gordon and Brushart laboratories with Canadian and German collaborators [29,[43][44][45][46][47] (reviews [33,[48][49][50][51][52]), and in human patients in the Chan laboratory in Canada [53][54][55] (reviews [33,48,52,56]), demonstrated that brief low frequency, electrical stimulation of the nerve proximal to the site of transection and surgical repair, accelerated motor and sensory nerve regeneration. More recently, a positive conditioning effect of electrical stimulation of the intact nerve, prior to nerve transection and repair, has been pursued in rat studies in the laboratories of Chan and Webber [57][58][59][60].…”