**7. Conclusions**

Lateral internal sphincterotomy is still the gold-standard treatment for chronic anal fissures when the first-line and second-line therapies such as topical nitrates, calcium-channel blockers, and botulinum toxin have failed. It is associated with increased healing rates and improved quality of life in patients with anal fissures. Therefore, surgical intervention can even be offered in select patients without first confirming the failure of pharmacological therapies.

The technique of lateral internal sphincterotomy has been evolved over the years in terms of approaches (open/closed), the level of division of the internal sphincter (complete/partial), and the extent of sphincterotomy (to the dentate line/up to the fissure apex). A tailored-fashion sphincterotomy that is based on the individual characteristics of each patient has come upfront in recent years. As a tailored-fashion technique, the spasm-controlled sphincterotomy has been performed as a safe and effective method with low rates of incontinence and treatment failure.

Determining an individualized technique, which involves objective methods to measure the sufficient level of sphincterotomy either by calibrators and a surgical measure or anal ultrasonography and manometry, has the utmost importance in preventing postoperative incontinence, increasing healing rates, and improving quality of life.
