Idiopathic hypertensive anal canal: a place of internal sphincterotomy

Hypertensive anal canal is frequently known to be associated with the presence of anal fissure. Based on clinical experience, we hypothesized that idiopathic anal sphincter hypertonia was a condition equivalent to anal fissure, and therefore, it could be treated the same way.

Sixty-three patients complaining of anal pain without any anal pathology and ten healthy volunteers were examined. All patients underwent clinical evaluation, neurological examination, anorectal manometry, and measurement of pudendal nerve terminal motor latency. All patients with hypertensive anal canal were randomized into three groups. Group I (surgical group) underwent closed lateral sphincterotomy (LS), group II using nitroglycerine ointment (GTN), and group III received injection of botulinum toxin in internal sphincter. Post-procedures data were recorded at follow-up period.

The mean resting anal pressure (MRAP) was significantly higher in the patient group (114.6 +/- 7.4 mmHg) than control group (72.5 +/- 6.6 mmHg, P < 0.001). Anal pain is the main presenting symptoms aggravated by defecation and not relived by analgesics or local anesthetics. After LS, pain visual analogue scale decreased significantly at follow-up period than after chemical sphincterotomy using GTN or BTX (P = 0.001). There was a significant decrease in MRAP postoperatively from 114.6 +/- 7.4 to 70.8 +/- 5.5 mmHg than after using GTN or BTX (P = 0.03).

Idiopathic hypertensive anal canal is a fact and already exists presented by anal pain aggravated by defecation. It can be managed safely by closed lateral sphincterotomy, but chemical sphincterotomy had a minor role in its management.