Excision of anal fistula with closure of the internal opening - Functional and manometric results

PURPOSE: The aim of this study was to evaluate the results concerning recurrence and continence after sphincter-saving surgery for fistula-in-ano. METHODS: Forty-two patients with anal fistula traversing the sphincter were operated on with fistula excision and closure of the internal opening. Patients answered a questionnaire concerning bowel habits and continence before and 3 and 12 months after surgery. A subgroup of 19 patients were also examined with anal manometry. RESULTS: Twenty-three (55 percent) patients healed primarily after surgery and a further 10 (24 percent) after one reoperation, whereas 7 (17 percent) required 2 to 4 reoperations until healed. In two patients therapy was changed to cutting seton treatment. After I year 21 of 36 (58 percent) patients reported improved or unaffected continence and 11 (31 percent) reported a slight and 4 (11 percent) a major decrease in continence. Detailed data on preoperative continence were missing for five patients, and one had a colostomy at late follow-up. Anal manometry showed a significant decrease in resting pressure after three months and a further decrease in both resting and squeeze pressures after one year. CONCLUSION: Surgery for anal fistula with excision and advancement flap has a fairly high initial recurrence rate but a good final success rate. A decrease in continence is seen also after this kind of surgery for anal fistula. Manometric results suggest that this is associated with an impaired internal anal sphincter function.