Sphincter-Sparing Surgical Alternatives for Chronic Anal Fissure: the Place of Fissurotomy

Excerpt

To the Editor—The authors are to be congratulated for proferring a novel etiopathogenesis for chronic anal fissure treated by fissurotomy, presenting very good clinical results for this nonsphincterotomy approach.1 It is accepted that dorsal anal fistulas, (which are relatively uncommon), are almost always associated with an underlying anal fissure but it is not the general experience that most fissures are accompanied by a fistulous track beyond the cutaneous pocketing surrounding the exposed internal anal sphincter. On this logic, it would be expected that dorsal anal fistulas should be much more common in medically-treated fissures. The authors’ theory may explain the relatively poor cutaneous blood supply differentially affecting the fissure as opposed to the sphincterotomy site but this should also be a feature of any cryptogenic anal fistula; a finding not previously reported. It should be recognized that the causes of postsphincterotomy leakage are multifactorial and only part of this is secondary to the sphincterotomy itself even when it is intended to be limited in extent.2 Our group has previously shown in fissure patients that there is a variable recovery of the rectoanal inhibitory wave (an internal anal sphincter function) particularly when there is external anal sphincter atrophy;3 with, in some cases, preoperative evidence of a constitutively shorter subcutaneous component of the external anal sphincter overlapping the internal anal sphincter termination.4 This would render the distal anal canal relatively unsupported following internal anal sphincterotomy and contribute to predictable postoperative incontinence. Moreover, internal anal sphincterotomy may be accompanied by a weakened voluntary sphincter function even when there are continent postsphincterotomy outcomes,5 where Shafik and colleagues have shown external anal sphincter atrophy with a change in its histomorphologic structure up to 10 months following internal anal sphincter excision in a canine model.6 …