Prevalence of Anatomic Anal Stenosis in Patients with Chronic Anal Fissure and Results of Lateral Internal Sphincterotomy

Cho, Dong Yoon; Kim, Dong Yi; Kim, Young Jin

Abstract

PURPOSE: The aim of this study was to estimate the prevalence of anatomic anal stenosis in patients with chronic anal fissure (CAF) and ascertain the results of lateral internal sphincterotomy (LIS) using a new calibrator.
METHODS
Ninety-eight adults with CAF and a control group of 40 normal adults underwent anal calibration under spinal anesthesia. The calibrator was a conical design and the diameter was scaled in increments of 1 mm. The calibration was standardized and the reliability of it was assessed by two independent examiners for the same group (n=45). Confounding effects of age, sex, body weight, and height on the anal caliber were studied. The internal sphincter was divided to the level of the dentate line during LIS.
RESULTS
The anal caliber was 34.6 +/- 1.4 mm (mean +/- SD) in the control group and 28.7 +/- 3.0 mm (mean +/- SD) in patients with CAF. Excellent correlation was obtained between the two examiners (r=0.958). The confounding effects of age, sex, body weight, and height were not significant. Therefore, anal stenosis was defined as when the measurement was 31 mm or below (mean-2SD of control value). Stenosis was present in 82 of 98 patients (84%) with CAF. Patients with stenosis had an anal caliber of 27.9 +/- 2.5 mm, with a range of 21 to 31 mm. Following LIS, 91 of 98 patients (93%) with CAF attained the normal range, two patients still had stenosis, and five patients had an anal caliber exceeding the normal value.
CONCLUSIONS
Anatomic anal stenosis was found in 84% of the patients with CAF. Ninety three percent of these patients attained a normal anal caliber, 2 percent of the patients still had stenosis and 5 percent of the patients had an anal caliber exceeding the normal value after LIS.