The Effect of Sphincter Pressure and Anal Length on Surgical Decision in Chronic Anal Fissure

Background/Objectives: Chronic anal fissure, an anorectal condition, is characterized by internal anal sphincter fibers at the base of the fissure. The lifetime prevalence is 7-8%. Medical management and lifestyle modifications are the first-line treatments, whereas chemical or surgical internal anal sphincterectomy is an option for refractory cases. The aim of this study was to evaluate the impact of surgical anal canal length and sphincter pressure on postoperative symptom relief and continence outcomes. Methods: A total of 26 patients diagnosed with chronic anal fissures were selected for surgical treatment. Five patients voluntarily withdrew, leaving 21 cases for analysis. In patients undergoing open lateral internal sphincterotomy, anal canal length and sphincter pressure were assessed preoperatively and three months postoperatively using endoanal ultrasonography and high-resolution anal manometry. Results: Postoperatively, all patients experienced complete resolution of pain and bleeding. The expected decrease in resting pressure was not significantly associated with sex. A significant weight gain was observed postoperatively (p = 0.001). Although a significant decrease was observed in preoperative sphincter resting pressure and VAS scores, Wexner scores remained unchanged. Preoperatively and postoperatively, mean sphincter pressure was significantly lower in the spontaneous vaginal delivery group than that in the non-spontaneous vaginal delivery group (p < 0.05). Patients with short anal canal lengths had greater pressures reductions, though not statistically significant. Conclusions: Lateral internal sphincterotomy is an effective and safe treatment for chronic anal fistula when performed by experienced surgeons. Anal canal length may influence postoperative complications and surgical decisions. Larger studies are needed to confirm these findings.