Preliminary results of a novel sphincter-sparing technique-fistula occlusion with the internal sphincter flap (FOISF)-for high complex anal fistulas

Background and aim: High complex anal fistula is a clinical challenge for proctologists and a nightmare for patients. Although the sphincter-sparing approach seems an ideal surgical intervention, there remains room for improvement in treatment efficacy. Herein, we introduce an enhanced sphincter-sparing approach, namely the fistula occlusion with the internal sphincter flap (FOISF), for treating high complex anal fistulas.

Methods: This study evaluated 15 patients with high complex anal fistulas who underwent FOISF between October 2021 and December 2022 in the Sixth Affiliated Hospital, Sun Yat-sen University (Guangzhou, P. R. China). Data on success rates, anal function, and various surgical characteristics were subjected to rigorous analysis.

Results: All patients underwent the FOISF procedure, with a median operation time of 53 min. Fourteen patients achieved primary intention healing, while one patient healed by second intention. No recurrence was observed over a follow-up period of 14-30 months. All patients exhibited satisfactory anal continence, with no statistically significant difference observed between preoperative and postoperative Wexner scores (P = 0.331). A significant improvement in the quality of life was observed when compared with the preoperative assessment (P < 0.001).

Conclusion: The preliminary results of the FOISF procedure present an effective approach to treat high complex anal fistula.