Changes in the function of the anal sphincter complex and generated anal pressure at different anatomical levels after elastic ligature application in patients with anal fistula

Abstract

Purpose: The purpose of the present study was to measure by means of especially developed apparatus the anal and intrarectal pressure before and after different operations for perianal fistulas as well as to correlate the degree of incontinence evaluated by Fecal Incontinence Severity Index (FISI) with changes in the measured pressures and type of operation used.Material and methods: The study covered 311 patients with perianal fistulas who were operated with several methods. Anal canal pressures at 5 different levels were measured by the especially developed apparatus at rest, squeezing and cough, before and after 6 months of operation. FISI form was used for incontinence detection.Results: Resting, squeezing and cough pressures were higher in men before and after operations. Average reduction of anal rest pressure by 10-15%, at contraction by 20-25% and at cough by 5-10% resulted in mild incontinence according to FISI score. Average reduction of anal rest pressure by 20-25%, at contraction by 30-40% and at cough by 20-25% correlated with postoperative moderate degree of incontinence according to FISI score. No severe incontinence was registered by FISI examination. Usage of the method of elastic ligation of perianal fistulas, i.e. the method of Hippocrates-Thoma Junescu caused the highest percentage of postoperative mild degree incontinence (15,9%) and moderate one (4,3%) by FISI. No patients presented with severe degree of incontinence.Conclusion: The method of anal sphincter tonometry demonstrated a significant reduction of anal pressure after surgery for anal fistulas. This objective decrease of anal sphincter tone correlated with the higher FISI score arguing of postoperative incontinence. The method of Hippocrates-Thoma-Junescu resulted in the highest rate of incontinence (around 20%) and anal pressure reduction