title: Physiological and histochemical adaptation of the electrically stimulated gracilis muscle to neoanal sphincter function.
abstract: The physiological and histochemical characteristics of the gracilis muscle were studied in 19 patients undergoing electrically stimulated gracilis neosphincter construction. Indications for surgery were faecal incontinence (n = 11) and reconstruction following sphincter excision or congenital absence (n = 8). Transposition of the gracilis muscle around the anal canal followed by chronic low-frequency electrical stimulation was associated with a shift in the frequency-response curve and a prolongation of the time-course of individual muscle twitches suggestive of transformation to a slow-twitch fatigue-resistant type. Temporary cessation of electrical stimulation resulted in a reversal of the frequency-response changes. Muscle biopsies taken before and a median of 80 (range 49-137) days after transposition and low-frequency electrical stimulation indicated a significant increase in the proportion of type 1 fibres and a significant decrease in their diameter. These results show that the human gracilis muscle is capable of physiological and histochemical adaptation to long-term neosphincter function.
authors.affiliation: Department of Surgery, Royal London Hospital, UK.
authors.forename: B D
authors.initials: BD
authors.lastname: George
authors.forename: N S
authors.initials: NS
authors.lastname: Williams
authors.forename: J
authors.initials: J
authors.lastname: Patel
authors.forename: M
authors.initials: M
authors.lastname: Swash
authors.forename: E S
authors.initials: ES
authors.lastname: Watkins
mesh_terms: D000222:Adaptation, Physiological; D000293:Adolescent; D000328:Adult; D000368:Aged; D001003:Anal Canal / Q000002:abnormalities / Q000503:physiopathology* / Q000601:surgery; D004558:Electric Stimulation; D005242:Fecal Incontinence / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology; D009132:Muscles / Q000637:transplantation*; D011312:Pressure