**Core Concept**
Surgery for fissure in ano is a procedure aimed at relieving the tension on the anal sphincter and promoting healing of the anal fissure. The primary goal is to reduce the spasms of the internal anal sphincter, which can lead to chronic pain and difficulty with bowel movements.

**Why the Correct Answer is Right**
The correct surgical procedure for fissure in ano is lateral internal sphincterotomy (LIS). This involves making a small incision in the internal anal sphincter to reduce its spasms and promote blood flow to the affected area. The LIS procedure is effective because it allows for relaxation of the internal anal sphincter, reducing the pressure on the anal mucosa and facilitating healing of the fissure.

**Why Each Wrong Option is Incorrect**
* **Option A:** Hemorrhoidectomy is a surgical procedure that involves removing hemorrhoids, which is not directly related to treating fissure in ano.
* **Option B:** Fistulotomy is a procedure used to treat anal fistulas, not fissures.
* **Option C:** Anal dilatation is a procedure that involves stretching the anal sphincter, but it is not a definitive treatment for fissure in ano.

**Clinical Pearl / High-Yield Fact**
It's essential to note that surgery for fissure in ano should only be considered after failure of initial medical management, which includes topical nitroglycerin, calcium channel blockers, and fiber supplements.

**Correct Answer: C. Anal dilatation is a procedure that involves stretching the anal sphincter, but it is not a definitive treatment for fissure in ano.