Type of Lateral Internal Sphincterotomy Incision: Parallel or Vertical?

The lateral internal sphincterotomy (LIS) technique is considered the optimal surgical treatment for chronic anal fissures (CAFs), although questions remain regarding the best technique. The present study investigated whether the type of anoderm incision (vertical or parallel to the anus) affects wound healing, wound-related complications, incontinence, and recurrence rates in CAF patients undergoing open LIS.

This prospective randomized clinical study divided 52 patients undergoing LIS for CAF into two groups. In group 1 (n = 25) the incision was made vertical to the anus; and in group 2 (n = 27) it was made parallel to the anus. Incision sites were not sutured in either group. Wound site complications, wound healing times, perianal itching, incontinence, and recurrence rates were evaluated.

Complications involving bleeding, hematoma, abscess formation, or fistulization were not observed in either group. Complications were observed in 5 patients of group 1 (1 wound infection, 1 ecchymosis, 2 flatus incontinence, 1 recurrence) and in three patients of group 2 (2 wound infections, 1 flatus incontinence). Overall wound complication, incontinence, and recurrence rates were 7.7, 5.8, and 1.9%, respectively. The two groups did not differ significantly in terms of wound complications, incontinence, or recurrence. Itching duration was significantly longer in group 1 (p < 0.0001) Complete wound healing was slower in group 1 than group 2 (19.44 ± 6.82 vs. 10.59 ± 3.48 days, p < 0.0001).

Wound healing time and perianal itching duration were significantly reduced when anoderm incisions were made parallel to the anus compared to those made vertical to the anus.