American Society for Peripheral Nerve

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Brief post-surgical electrical stimulation enhances sensory function following digital nerve transection: a double blind, randomized controlled clinical trial
Joshua N. Wong, MD1, Jaret L. Olson, MD, FRCSC1, Michael J. Morhart, MD, MSc, FRCSC1 and Chan K. Ming, MD, FRCPC2
1Department of Surgery/Division of Plastic Reconstructive Surgery, University of Alberta, Edmonton, AB, Canada, 2Division of Physical Medicine and Rehabilitation, University of Alberta, Edmonton, AB, Canada

Background: Upper extremity peripheral nerve injuries are common, costly and can result in marked functional debilitation. Despite surgical advances, the functional outcomes are often unsatisfactory. A promising adjuvant therapy to augment nerve regeneration is brief post-surgical electrical stimulation (ES). Pro-regenerative effects have been shown with 1h of low-frequency ES in animal motor and sensory axons. As well, ES has significantly improved motor nerve regeneration in patients with severe axonal loss due to carpal tunnel compressive injury. However, whether ES may also benefit recovery of sensation in humans remains unknown. With the crucial role that sensory feedback plays on fine dexterous tasks, this represents a major missing void. Hypothesis: ES would result in greater physiological and functional improvements in sensory recovery of patients with complete digital nerve transection compared to surgical repair alone. Methods/Design: Adult subjects with completely transected digital nerve in the hand without pre-existing neuropathy were recruited. After standard surgical repair was performed, a paired of electrode wires were placed proximal to the coaptation site. Patients were randomized to the placebo control group (1h null stimulation) or ES group (1h continuous 20 Hz stimulation). Quantitative cold detection threshold was used as the primary outcome measure. Secondary outcomes included pressure detection threshold, two-point discrimination, quantitative warm detection threshold, and DASH Disability scores. Assessments were performed at baseline and then monthly for 6 months after surgery. Results: Between July 2011 and June 2012, 36 (1:1 allocation) patients were recruited from hand clinics at the University of Alberta. Patient demographics, injury characteristics and baseline functional deficits were similar in both groups (p>0.05). However, after the first two months, those in the ES group began to show significantly greater recovery in cold detection thresholds compared to the control group (tw ANOVA interaction: p<0.001; post-hoc Tukey: p<0.001). By 5 to 6 months, the divergent trend became even more marked with the ES patients achieving near normal function. Similar differences between the two groups were also seen with the secondary outcome measures: pressure detection thresholds (p=0.015; p<0.001), two-point discrimination (p=0.018;p<0.001), warm detection threshold (p=0.001; p<0.001), disability score (p=0.049; p=0.014) and work score (p=0.016; p=0.027). Conclusion: ES enhances sensory recovery in humans following complete digital nerve transection. This procedure is relatively simple, inexpensive and only takes an hour. Combined with its beneficial effects on motor regeneration, ES is a potentially feasible treatment for use in a wide variety of clinical settings with different peripheral nerve injuries.


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