Pouch Surgery — The Importance of the Transitional Zone

Abstract

Patients with preservation of the transitional zone of the anal canal have less leakage and less need to wear pads than patients who have had mucosectomy. There is a significant difference in mean maximum resting pressure between patients that have had anal transitional zone preservation and mucosenomy. With preservation of the anal transitional zone, a mean maximum resting pressure of 57.6±3.8 mmHg was obtained compared with 47.3±4 mmHg in the mucosectomy group. Preservation of the resting pressure is dependent on preservation of internal anal sphincter integrity. The integrity of the sphincter is injured during mucosectomy due to anal dilation. Other factors affecting continence and stool frequency, such as diet, antidiarrheal medications, stool consistency and compliance, when examined were found to be unrelated factors.Can J Gastroenterol I 990;4(7):428,431Key Words: lleo-anal anastomosis, Pressure studies, Surgery Les 'ostomies' -Importance de la zone de transition RESUME: Les patients chez qui la zone de transition du canal anal a ete preservee souffrent d'un nombre moindre de fuites ct eprouvent moins le besoin <le porter des tampons que les patients qui ont subi une mucosectomie. II existe une difference significative entre les deux groupes quanta la pression maximum moyenne de repos. Dans le groupe chez qui la zone de transition anale a ete preservee, la press ion maximum moyenne du sphincter au repos era it de 5 7 ,6±3 ,8 mm Hg par rapport a 4 7,3±4 mm Hg clans le groupe ayant subi une mucosectomie.La preservation de la pression de repos depend de l'integrite du sphincter anal intemc. Or, la mucosectomie inflige un traumatisme direct au sphincter anal lors de sa dilatation. D'autres facteurs influant sur la continence et la frequence des selles (regime alimentaire, antidiarrheiques, consistence des selles et compliance) ont ete examines mais ne semblcnt pas intervenir.The Cleveland Clm1c Foundation,

Restorative proctocolectomy and ileal pouch-anal anastomosis for familial adenomatous polyposis revisited

“…It is self-evident that the more the anal canal is manoeuvred and stretched, the more likely there will be an adverse impact on sphincter control. Furthermore, it has been speculated that continence could be improved by preserving ATZ, which is thought to be important because it contains nerve endings that differentiate solid and liquid stools from gas [51,64,[71][72][73][74][75]. Care must also be taken for the extent of anorectal smooth muscle resected at the time of mucosal proctectomy in order to preserve postoperative bowel and anal sphincter function [4,16,64,76,77].…”

Risk of dysplasia in the columnar cuff after stapled restorative proctocolectomy

“…In the initial description of the procedure in 1978 3 , resection of the entire rectal epithelium was used to eliminate the recognized risk of malignant change in colitic mucosa. The availability of stapling instruments has simplified the operation and improved the functional results by retaining the anal transitional zone 4 . In stapled restorative proctocolectomy (SRP), a 'cuff ' of columnar epithelium, which has the potential risk of malignant change, is retained from the top of the anal transitional zone to the level of the pouch-anal anastomosis.…”

Ileoanal Pouches - Is Mucosectomy Essential?

“…These results, hased primarily on retrospective uncontrolled studies (18,19,28), have not thus far been corroborated by prospective, nmJomized clm1cal trials. Indeed, Nicholl:., and colleagues at St Mark's Ho~pital in London (22) found no difference tn pelvic pouch function between IPAA and IPDRA in terms of continence, need to wear proteLt1ve pads and need for medication ( Table I).…”