Fine-tuning of the Extent of Lateral Internal Sphincterotomy: Spasm-controlled vs. up to the Fissure Apex

This study was designed to compare the results of controlled lateral internal sphincterotomy by using anal calibrators with those of sphincterotomy up to the fissure apex in a randomized, prospective fashion.

In the fissure apex group, sphincterotomy was extended to the level of the fissure apex, and in the spasm-controlled group, serial small sphincterotomies and anal caliber measurements followed until an anal caliber of 30 mm was obtained.

The preoperative anal caliber was 24 ± 1.9 (range, 20–28) mm and 24.9 ± 2.44 (range, 19–28) mm in the spasm-controlled and fissure apex groups, respectively (P = 0.127). Postoperatively, the spasm-controlled group had a mean anal caliber of 31.5 ± 1.28 (range, 30–32) mm, and the fissure apex group had 32.5 ± 2.33 (range, 25–37) mm (P = 0.035). In the fissure apex group, a significant negative correlation was determined between the postoperative anal caliber and time of relief of pain (r = −0.568, P = 0.001). The early (7 and 28 days) postoperative anal incontinence scores were significantly higher in the fissure apex group (P = 0.002, P < 0.0001, respectively). A significant positive correlation between the anal caliber measurements and anal incontinence scores at 28 days and 2 months also was noted in the fissure apex group (r = 0.406, P = 0.023; and r = 0.364, P = 0.044).

Controlled sphincterotomy provided a faster relief of pain, and it was associated with a lower rate of early postoperative disturbance of continence and an insignificantly lower rate of treatment failure compared with sphincterotomy up to the fissure apex.