Adequate internal sphincterotomy for chronic anal fissure: subcutaneous or open technique?

The extent of sphincter division by the subcutaneous or the open technique is examined by comparing the change in anal canal pressure after either method of sphincterotomy in twenty-eight patients with chronic anal fissure randomly allocated. In all patients the fissures healed at one month with significant reduction (P less than 0.01) of anal canal pressures to 52 (17-75) cmH2O after subcutaneous and 47.5 (35-100) cmH2O after open sphincterotomy, a 51 (22-77) and 50 (11-68) per cent reduction of their respective pre-operative measurements. Adequate sphincterotomy can be achieved by both techniques.