Comparing closed versus open lateral internal sphincterotomy for management of chronic anal fissure: systematic review and meta-analysis of randomised control trials

Chronic anal fissure is one of the most common benign anorectal health conditions, causing significant morbidity, quality of life, and economic loss. Eight randomized controlled trials with a total population size of 1035 were eligible for analysis. Seven studies included both males and female, while one only included females. The majority of randomized controlled trials involved female dominance [54.9% (43.5-66.3)] and posterior midline location [86.1% (95% CI 81.5-90.8%)]. This meta-analysis of randomised control trials found that overall postoperative healing was 90.2%, recurrent anal fissure was 3.7%, and postoperative incontinence was 8.9% after LIS. Even though there was no statistically significant difference, closed lateral internal sphincterotomy (LIS) had higher rates of recurrent anal fissure (RR = 1.73 (95% CI 0.86-3.47, p = 0.90, I2 = 0%) and lower rates of postoperative incontinence rate (RR = 0.60 (95% CI 0.37-0.96, p = 0.76, I2-0) as compared with open LIS. We recommended that closed lateral internal sphincterotomy (LIS) is a safe and effective surgical treatment option for chronic anal fissures.