Changes in the values of the anal pressure at different anatomical levels after application of elastic ligature in patients with anal fistula. Study on 311 patients.

Aim: To measure with specially developed apparatus anal and intrarectal pressure before and after different operations for perianal fistulas. Moreover, to correlate the degree of incontinence evaluated by FISI with changes in measured pressures and type of service used. Methods: 311 patients with perianal fistulas operated with several operative methods. Pressures of the anal canal at five different levels were measured by the specially developed apparatus at rest, squeezing and cough, before and after six months of operation. FISI form used for detection of incontinence. Appropriate statistical methods were used. Results. Resting, squeezing and cough pressures were higher in men before and after operations. The reduction in anal rest pressure by an average of 10-15%; at contraction by an average of 20-25% and cough by an average of 5-10% leads to the development of mild incontinence by FISI. Drop in the rest anal pressure by an average of 20-25% at contraction by an average of 30-40% and at cough by an average of 20-25%. It correlated with the postoperative moderate degree of incontinence by FISI in our survey. Severe incontinence by FISI in our study, are not registered. The method of Hippocrates-Thoma Junescu has the highest percentage of postoperative incontinence - 15.9% - mild degree and 4.3% moderate degree by FISI. Severe degree of incontinence not registered in our study. Conclusion: Method of anal sphincter tonometry demonstrates significant drop of anal pressure after operations treating anal fistulas. This objective decrease of anal sphincter tone correlates well with higher FISI score showing postoperative incontinence. The method of elastic ligation (of Hippocrates-Thoma-Junescu) of perianal fistulas has highest rate of incontinence (around 20%) and causes a greatest drop of anal pressure.