PMY Tang, MWY Leung, JWS Hung, KLY Chung, CSW Liu, NSY Chao, KKW Liu

Abstract

Purpose: The use of anorectal manometry in the evaluation of anal sphincter function has been well established. The new three dimensional (3D) high resolution anorectal manometry (HRARM) would provide additional information regarding the symmetry of the anal sphincter pressure. Methods: We prospectively recruited 17 patients with defaecation disorders: 3 patients with idiopathic constipation, 8 patients with Hirschsprung's disease and 6 patients with anorectal malformation. 3D HRARM was performed. The resting pressure and squeeze pressure at the physiological sphincter were measured and analyzed. We define the inter-quadrant pressure asymmetry index (Δp) mathematically, Δp = (maximal pressure - minimal pressure)/maximal pressure x 100%. Results: There was an increasing inter-quadrant pressure asymmetry index (Δp) observed in the anal pressure profiles in patients with history of Soave pullthrough, myomectomy, Duhamel operation and posterior sagittal anoplasty (PSARP). The asymmetry is more pronounced in squeeze pressure in the Soave pullthrough group, and less pronounced in squeeze pressure in the myomectomy, Duhamel and PSARP group. Conclusions: The inter-quadrant pressure asymmetry index (Δp) reflects the post operative status of anal sphincter, which is influenced by the different surgical maneuvers employed in the operations. The symmetry of anal sphincter pressure might provide useful anatomical parameters in the assessment of surgical outcomes.