Patterns of impaired internal anal sphincter activity in patients with anal fissure

Aim The patterns of impaired internal anal sphincter activity were studied in patients with anal fissure (AF). Method Twenty healthy controls and 61 patients with acute AF were studied, using anorectal manometry with electromyography (EMG), and 53 patients with chronic AF using high-resolution manometry and ultrasonography. Mean and maximal resting anal pressure (MRAP), spontaneous rhythmic slow and ultraslow waves (USW) and relaxation induced by rectal distension were measured. Results Patients with acute AF had higher mean (106.4 +/- 28.1mmHg) and maximal resting anal pressure (161.5 +/- 43.7mmHg) than those with chronic AF (P<0.05); 95% of patients had slow waves (SW) and 67% ultraslow waves. Patients with chronic AF had higher mean (92.4 +/- 22.6mmHg) and maximal resting anal pressure (117.5 +/- 32.0mmHg) than controls and 94% of patients had slow waves and 69% ultraslow waves. Patients with ultraslow waves (with either acute or chronic AF) had increased internal sphincter hypertonicity (mean and maximal resting pressure), decreased internal sphincter relaxation and increased after-contraction following rectal distension. Conclusions Patients with acute AF had higher hypertonicity than those with chronic AF and both had increased spontaneous rhythmic activity (waves). Patients with AF and ultraslow waves had higher internal anal sphincter hypertonicity and reduced internal sphincter relaxation and enhanced after-contraction following rectal distension.