Percutaneous neuromodulation therapy: does the location of electrical stimulation effect the acute analgesic response?

Abstract

We studied the effect of the location of electrical stimulation on the acute analgesic response to percutaneous neuromodulation therapy in patients with nonradiating neck pain. Sixty-eight patients received three different nonpharmacologic modalities, namely "needles only" (neck), local (neck) dermatomal stimulation, and remote (lower back) dermatomal stimulation in a random sequence over the course of an 11-wk study period. All treatments were given for 30 min, 3 times per week for 3 wk, with 1 wk "off" between each modality. The assessment tools included the health status survey short form (SF-36) questionnaire, as well as 10-cm visual analog scales for assessing pain, physical activity, and quality of sleep. The pain visual analog scale was repeated 5-10 min after each treatment session. The daily oral nonopioid analgesic requirements were recorded in the patient diary during the entire study period. At the end of each 3-wk treatment block, the SF-36 questionnaire was repeated. Compared with needles only and remote dermatomal stimulation, local dermatomal stimulation produced a significantly greater decrease in pain (38%+/-17% vs 9%+/- 16% and 13%+/-18%), increase in physical activity (41%+/-21% vs 11% +/-17% and 16%+/-15%), and improvement in the quality of sleep (34% +/-18% vs 7%+/-17% and 10%+/-18%) compared with baseline values (P<0.05). The need for oral analgesic medications was decreased by an average of 6%+/-15%, 37%+/-18%, and 9%+/-13% during the 3-wk treatment period with the needle only, local dermatomal, and remote dermatomal stimulation, respectively. The posttreatment SF-36 test results revealed that all three modalities produced improvements compared with the prestudy scores for both the physical component summary and mental component summary. However, the magnitude of the changes in the physical component summary and mental component summary with local dermatomal stimulation was significantly greater (+7.9 and +3.6, respectively) than needle only (+3.4 and +1.7, respectively) or remote dermatomal stimulation (+3.7 and +1.9, respectively). No side effects were reported at the needle insertion sites. We conclude that electrical stimulation at the specific dermatomal levels corresponding to the local pathology produces greater short-term improvements in pain control, physical activity, and quality of sleep in patients with chronic neck pain.