Transcutaneous Electrical Acustimulation Improves Constipation by Enhancing Rectal Sensation in Patients With Functional Constipation and Lack of Rectal Sensation

INTRODUCTION: Reduced rectal sensation is involved in the pathophysiology of constipation. The aim of this study was to investigate the effects of transcutaneous electrical acustimulation (TEA) at acupuncture point ST36 on constipation and rectal sensation as well as autonomic functions in patients with constipation and reduced rectal sensation. METHODS: In an acute study, anorectal motility and sensation tests were performed in constipation patients (N = 53) who were treated with TEA at ST36 or sham points. In a chronic study, patients (N = 18) underwent 2 weeks of TEA or sham-TEA in a crossover design. RESULTS: Chronic TEA increased spontaneous bowel movements (3.72 vs 2.00 per week with sham-TEA, P < 0.0001) and significantly reduced constipation symptoms and increased quality of life in comparison with sham-TEA (P < 0.05). Acute TEA reduced the sensation threshold in response to rectal distention for the urge of defecation and maximum tolerable volume (P < 0.05, vs baseline); chronic TEA reduced the sensation thresholds for first sensation and desire of defecation, and decreased the threshold volume to an elicit rectal anal inhibitory reflex (P < 0.05). Both acute and chronic TEA increased parasympathetic activity (P < 0.05). DISCUSSION: TEA at ST36 improves chronic constipation by enhancing rectal sensation possibly mediated by the reinforcement of parasympathetic activity in patients with functional constipation and reported lack/absence of rectal sensation.