The Effects of Electroacupuncture of the Myofascial Trigger Points on the Pain and the Sensory Thresholds in Chronic Low Back Pain

摘要

Relevance: Lumbar myofascial trigger points (MTP) are a major cause of chronic low back pain (LBP) that electroacupuncture (EA) may deactivate more efficiently to contribute to a better analgesia. Objective: This study compares analgesia and peripheral sensory thresholds when LBP patients receive manual acupuncture (MA) with or without EA of lumbar MTP. Methods: Patients with chronic LBP and presenting active MTP received randomly 4 weekly 45-min sessions of MA only (n Z 15) or with EA of their MTP (n Z 15) (AS-4, Schwa Medico, 150 ms, 100 Hz, sub-noxious intensity). We assessed Quantitative Sensory Testing (QST) before and 4 weeks after treatment, with VAS before each session. QST measured electrical thresholds for non-nociceptive A-beta fibers, nociceptive A-delta and C fibers in 2 dermatomes: from the most affected side of the LBP (L4) and the contralateral pain-free arm (C7). VAS reduction of 3 or below 3 on a 10 points scale was considered clinically relevant. Paired t-test compared thresholds (mean [SD]) and Wilcoxon test compared VAS (median [IQR]), significant p < 0.05. Results: Reduction of VAS reached clinical and statistical relevance after the 1st session in the EA (from 7[3] to 3[1]) but not in the MA (6.8 [3] to 4.9 [3.6]). From session 2 to 4, VAS reached clinical and statistical relevance in both groups. However, 4 weeks post-treatment, VAS for EA was significantly lower than for MA (2.1[1] vs. 4[1]) Pre-treatment, thresholds for A-delta and C fibers in L4 were significantly lower than those in C7 for both groups (respectively 60[30] and 63[10] % of C7 for EA and 65[11] and 60[36] % for MA) but corrected only for EA (91[11] and 106 [36] %).