Local effects of acupuncture on the median and ulnar nerves in patients with carpal tunnel syndrome: a pilot mechanistic study protocol

BACKGROUND: While acupuncture’s mechanism of action is not fully understood, there is consensus that the nervous system plays a key role in processing its effects. This research is based on the structural theory of acupuncture, which aims to correlate the location of acupuncture points to peripheral nerves, spinal segments, and spinal plexuses. This mechanistic study explores the close anatomical association between the Pericardium meridian/median nerve and the Heart meridian/ulnar nerve in an attempt to produce electrophysiologic data measuring acupuncture’s direct, nerve-specific effect on the underlying nerves. Specifically, the purpose of this research is to use nerve conduction studies (NCSs) and quantitative sensory testing (QST) to assess for any local, nerve-specific effect of three acupuncture modalities on two anatomically distinct nerves in the forearm — the median and ulnar nerves — in subjects with carpal tunnel syndrome (CTS). The choice of CTS as an injured nerve model allows for comparisons between the response in an injured nerve (median) to that of a healthy one (ulnar). METHODS: Subjects with mild to moderate CTS will be randomized to three intervention groups: manual acupuncture and low- and high-frequency electroacupuncture. Each subject will receive two treatments, 1 week apart, to points in the forearm, which overlay the median nerve (Pericardium meridian) or the ulnar nerve (Heart meridian). Acupuncture will be administered in random order to minimize learning effects in sensory testing. During Week 1, baseline NCS and QST (vibration and cold detection thresholds) will be obtained in both nerve territories, followed by acupuncture and post-acupuncture NCS and QST measurements in both nerve territories. During Week 2, repeat baseline QST and NCS measurements will be obtained, followed by acupuncture to points overlying the nerve not treated in Week 1, followed by post-acupuncture NCS and QST measurements in both nerve distributions. DISCUSSION: This works aims to capture and characterize the local effects of acupuncture on an underlying nerve and compare them to those on a neighboring nerve. Quantifying acupuncture’s effects using physiologic parameters and discrete values could standardize treatment regimens and help assess their therapeutic effect. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03036657. Registered on 30 January 2017. Retrospectively registered. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13063-018-3094-5) contains supplementary material, which is available to authorized users.