SUSTAINED INTERNAL SPHINCTER HYPERTONIA IN PATIENTS WITH CHRONIC ANAL-FISSURE

PURPOSE: This study was designed to determine whether functional varia tions of internal sphincter activity occur in order to differentiate b etween patients with anal fissures from those with hemorrhoids. METHOD S: Thirty patients with chronic anal fissure (median age, 28 years; 12 females), 22 patients with hemorrhoids (median age, 37 years; 7 femal es), and 33 control volunteers (median age, 48.5 years; 21 females) un derwent ambulatory anal sphincter fine-needle electromyography and ano rectal manometry. RESULTS: The median internal sphincter electromyogra phy frequency was similar: fissure group, 0.49 Hz; hemorrhoid group, 0 .46 Hz (P > 0.05), and control group, 0.44 Hz (P > 0.05). Median anal resting pressures were similar in the fissure group (132 cm. H2O) and the hemorrhoids group (116 cm of H2O) (P > 0.05), but significantly gr eater than those in the control group (94 cm. H2O) (P < 0.05). The med ian number of transient relaxations of the internal anal sphincter wit h an associated rise in rectal pressure and fall in anal pressure was 1 (range, 0-4) per hour in the fissure group, 6 (range, 4-7) per hour in the hemorrhoid group, and 4 (range, 3-6) per hour in the control gr oup. Six patients with fissures were reassessed following lateral inte rnal sphincterotomy. Median anal pressure was 102 cm of H2O (P > 0.1 v s. controls) and the number of internal sphincter relaxations increase d to 4 per hour (P < 0.01 vs. preoperative number). CONCLUSIONS: Inter nal anal sphincter relaxation occurs on fewer occasions in patients wi th chronic anal fissures that have failed to heal in comparison to pat ients with hemorrhoids and normal controls. This evidence further supp orts the hypothesis that internal sphincter hypertonia may be relevant to the pathogenesis of this disorder.