Clinical results and manometric studies after rectal flap advancement for infra-levator trans-sphincteric fistula-in-ano.

Eleven patients with infra-levator trans-sphincteric fistula-in-ano underwent fistula excision with rectal flap advancement. The clinical results were assessed by interview and the physiological function determined by ano-rectal manometry. Nine patients underwent paired studies before and 5 (range 2 to 6) months after operation. Median maximum resting anal pressure was 84 (48-135) cm water before operation and 76 (29-139) cm water after operation (P = N.S.). Median maximum squeeze pressure was 112 (64-290) cm water before operation and 88 (44-316) cm water after operation (P = N.S.). The median sphincter length was preserved after operation. There was one clinical failure following the development of an abscess under the flap. All patients are continent and there have been no recurrences. We conclude that rectal flap advancement is an acceptable way to cure more complex fistula-in-ano. Good functional results are achieved by maintaining anal sphincter function together with preservation of the integrity of the anal margin.