Faecal incontinence after internal sphincterotomy for anal fissure

Minor defects in continence following open lateral sphincterotomy are relatively common. This study prospectively assessed 28 patients undergoing lateral sphincterotomy for chronic anal fissure. There were substantial differences in both resting and squeeze anal pressures and vector volumes in the incontinent cohort when compared to the continent post-operative cases. Mean preoperative high pressure zone was 37.6 mm, significantly higher than the postoperative value of 17.0 mm in the incontinent cases (p < 0.001). There was a significant difference in percent asymmetry of the anal canal at rest between incontinent and continent post-sphincterotomy cases, with a 6.7% increase in the former group and a 3.1% fall in the latter group (p < 0.001). It is unknown whether these changes are predictive for long-term continence.