Non-sphincter splitting fistulectomy vs conventional fistulotomy for high trans-sphincteric fistula-in-ano: a prospective functional and manometric study

Abstract

This study compared the clinical and physiological results of non-sphincter splitting fistulectomy (N-SSF) with those of sphincter splitting fistulotomy (SSF) for treatment of high trans-sphincteric fistula-in-ano. A prospective, observational study was undertaken in 70 consecutive patients with high trans-sphincteric fistula treated by SSF (n = 35) or N-SSF (n = 35). Anal manometry was performed before and 3 months after surgery. Anal continence was assessed using the Cleveland Clinic Florida Incontinence Score. There was no difference between the two groups in age, gender, presence of horseshoe extension, preoperative incontinence score and manometric values. The incidence of recurrence was similar between the two groups. The postoperative incontinence score of the SSF group was significantly higher than that of the N-SSF group (1.9 +/- 2.9 vs 1.1 +/- 2.9, P = 0.0347). Maximum resting pressure showed significant decrease after surgery in both groups (83.2 to 56.1 mmHg, P = 0.0001 and 85.1 to 58.4 mmHg, P = 0.0001). Voluntary contraction pressure and functional anal canal length did not change after N-SSF (137.6 to 138.2 mmHg, P = 0.9524 and 4.06 to 4.07 cm, P = 0.9524), but significantly decreased after SSF (120.2 to 96.7 mmHg, P = 0.0085 and 4.12 to 3.74 cm, P = 0.0183). Non-sphincter splitting fistulectomy for high trans-sphincteric fistula provided better functional results than fistulotomy. Less impairment of anal continence was achieved possibly not only by maintenance of the external anal sphincter function but also by preservation of the length of the high-pressure zone.