Minimal Lateral Internal Sphincterotomy (LIS): Is It Enough to Cut Less Than the Conventional Tailored LIS?

Anal fissure is a common anorectal condition, yet its pathogenesis remains unclear. Lateral internal sphincterotomy (LIS) is the gold standard treatment for chronic anal fissures that do not respond to conservative treatment; however, it has a risk of anal incontinence. We believe that fibrosis of the internal anal sphincter is an important factor in the pathogenesis of chronic anal fissure. In this study, we describe the minimal LIS method, a minimally invasive method where only the fibrotic portion of the internal anal sphincter is cut. We also describe the outcomes of this method.

We performed a retrospective review of 468 patients (270 male and 198 female) who underwent minimal LIS for chronic anal fissure in 2017 at Seoul Song Do Hospital. We analyzed the patients' clinical characteristics, manometry data, complications, and outcomes of minimal LIS. The outcomes of the surgery were assessed via questionnaires during the postoperative outpatient visits, beginning 2 weeks postoperatively.

The overall complication rate was 4.0% (19 patients). Delayed healing occurred in 14 patients (3.0%), perianal abscess was present in 3 patients (0.6%), and gas incontinence occurred in 2 patients (0.4%). All complications were improved with conservative treatment. Recurrence, defined as the recurrence of anal fissure more than 4 weeks after healing, was present in 6 patients (1.3%).

Minimal LIS is a safe and effective treatment option for patients with chronic anal fissure. Postoperative complications, especially incontinence and recurrence, are rare.