Physiological changes after postanal repair and parameters predicting outcome

Abstract

Abstract Nineteen patients have been studied before and 3 months after postanal repair. Physiological parameters have been compared with 16 age- and sex-matched controls. Twelve patients were substantially improved whereas seven obtained no clinical benefit. Pre-operative resting (P<0.005), squeeze (P<0.005) and strain (P<0.005) anal pressures at 2 cm were significantly less than controls. Similarly, pressures during all three events at 4 cm were significantly less than controls (resting P<0.05, squeeze P<0.005, strain P<0.025). Median volume of first leak during saline infusion was significantly less than controls (P < 0.005) as was the total tolerable volume (P < 0.005). Videoproctographic parameters which differed significantly from controls included pelvic floor descent at rest (P < 0.005), during contraction (P < 0.005) and straining (P < 0.05); resting and squeeze perineal descent (P < 0.005); and anal canal length at rest and straining (P < 0.005). Anorectal angles, rectal compliance, rectal sensation and emptying did not differ from controls. None of these parameters was improved by postanal repair. Patients not improved by operation could be detected pre-operatively by low resting (P < 0.05), squeeze (P < 0.025) and strain (P < 0.05) anal pressure at 2 cm as well as by videoproctographic evidence of increased pelvic floor descent at rest (P < 0.01), during contraction (P < 0.005) and straining (P < 0.005), excessive perineal descent at rest (P < 0.05), during contraction (P < 0.05) and during attempted defaecation (P < 0.05) and a short anal canal at rest (P < 0.05) and during straining (P < 0.025).