A Comparative Study on Surgical Technique for Lateral lntermuscular Fistula by Examination of Anal Physiology

A comparative study on surgical techniques for lateral intermuscular fistula was performed on 33 cases, in which transanal ultrasongraphy and anal manometry were performed preoperatively and in the 1st and 3 sd months postoperativery. These cases included 7 cases of lay open, 7 cases of seton, and technique 19 cases of sphincter-preserving technique. The results were as follows 1) When lay open is performed, contracture occurs rapidly on internal and external sphincter muscles with incised region in the border. Sphincter muscles aer opened and the resting and voluntary pressures decrease. 2) In the cases treated by the seton technique, when fistula is opened, wound healing occurs at the same time, however, decrease of resting pressure similar to that of lay open is found after opening because the internal sphincter muscle is cut. However, the external sphincter is incised to a lesser extent, and almost the same voluntary pressure as that of the sphincter preserving technique is obtained. 3) The sphincter preserving technique contributes to both radicality of the fistula and preservation of anal functions after the operation, and this seems to be the best technique for the treatment of lateral intermuscular fistula.