Efficacy of Lateral Internal Sphincterotomy with Chemical (Topical 0.2% GTN) Sphincterotomy for the Treatment of Chronic Anal Fissure

Abstract

Background: Chronic anal fissure (CAF) is a painful longitudinal tear of the anoderm, commonly caused by hypertonia of the internal anal sphincter leading to local ischemia and impaired healing. While lateral internal sphincterotomy (LIS) remains the gold standard surgical treatment, topical 0.2% glyceryl trinitrate (GTN) ointment offers a noninvasive chemical sphincterotomy alternative. However, comparative efficacy data across populations, particularly in South Asian settings, remain limited. Objective: To compare the efficacy and safety of lateral internal sphincterotomy versus topical 0.2% glyceryl trinitrate in the management of chronic anal fissure. Methods: This randomized controlled study was conducted at Bolan Medical Complex Hospital, Quetta, over one year. Thirty adult patients with chronic anal fissure were randomized equally into two groups: Group A underwent LIS, and Group B received topical 0.2% GTN twice daily for eight weeks. Clinical outcomes—healing, pain during defecation, and bleeding—were assessed at eight weeks. Data were analyzed using Chi-square and t-tests, with p < 0.05 considered significant. Results: Complete healing was achieved in 10 patients (66.7%) in the LIS group compared with 5 patients (33.3%) in the GTN group (p = 0.031, OR = 4.00, 95% CI 1.09–14.6). Persistent pain during defecation was more frequent after LIS (73.3%) than GTN (33.3%) (p = 0.062), while bleeding was higher in GTN (60%) than LIS (40%) (p = 0.053). One LIS patient (3.3%) developed transient flatus incontinence, and one GTN patient discontinued due to severe headache. Conclusion: Lateral internal sphincterotomy demonstrated superior healing with minimal, transient complications compared with topical GTN. LIS remains the preferred definitive treatment for chronic anal fissure, whereas GTN serves as a valuable noninvasive alternative for acute or early chronic cases