The twelve o'clock sphincterotomy: technique, indications, results.

Outflow obstruction at the level of the external sphincter in patients with neurogenic bladder dysfunction is common and transurethral sphincterotomy the treatment of choice. Based upon the anatomy of the striated muscle fibres forming the external sphincter and its blood supply, we find from our results on 35 patients, 17 of whom had a follow-up of more than three years, a transurethral sphincterotomy only in the 12 o'clock position as sufficient and preferable. The results indicate that this comparatively simple technique is effective in order to diminish outflow resistance at the level of the membranous urethra. Concerning fresh paraplegics with unbalanced reflex bladder, sphincterotomy is usually not performed earlier than one year after the injury.