How is IPAA performed in the treatment of ulcerative colitis (UC)?

Updated: Apr 01, 2019
  • Author: E Stanton Adkins, III, MD; Chief Editor: Harsh Grewal, MD, FACS, FAAP  more...
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Answer

Answer

A total proctocolectomy is performed through a midline abdominal incision. The ileum is divided close to the ileocecal valve with a stapler to preserve maximal ileal length. The ileal branch of the ileocolic artery is preserved, if possible, to provide optimal blood supply to the distal ileum. The rectum is stapled and divided within 1 cm proximal to the dentate line.

This procedure theoretically preserves the sensory nerve fibers in the anal transition zone that contribute to discrimination between gas and stool. Some deny the importance of retaining this zone, reporting no change in functional outcome when the anal transition zone is removed. [14] However, rectal mucosectomy may be performed and the ileum brought through a short seromuscular sleeve of rectum.

The dimensions of the pouch depend on the size of the patient. In adolescents, as in adults, a 9- to 12-cm pouch is created by folding the distal ileum on itself in a J configuration and by using a linear cutting stapler to place staples longitudinally along the antimesenteric border between the two limbs of the J to create a reservoir. (See the image below.)

A "J" pouch reservoir is created by placing linear A "J" pouch reservoir is created by placing linear cutting staples in a longitudinal orientation between the limbs of the J.

Limb lengths of 8-10 cm are used in small children. The bowel at the lower end (ie, curve) of the J is then used to create an anastomosis to the anus with a circular stapling device or sutures. Because of the increased incidence of cancer in patients with UC and primary sclerosing cholangitis (PSC), complete mucosectomy to the dentate line and creation of a handsewn pouch-anal anastomosis have been recommended in these patients.

To ensure a tension-free anastomosis at the anus, numerous techniques may be used to gain length in the small bowel. First, the ligament of Treitz may be mobilized to allow the proximal jejunum to turn toward the pelvis in a more gradual manner. The peritoneum overlying the small bowel mesentery may be sequentially opened in an orientation perpendicular to the superior mesenteric artery ("stair stepping") to release tension and provide length.

The superior mesenteric artery may be divided just distal to the origin of the first or second arterial arcade. This proximal division preserves distal collateral flow and provides length. Finally, vein interposition grafts may be used as a last resort in the most extreme cases, where length is prohibitively short. [15]

The need for fecal diversion after IPAA is controversial in adult patients. Because the need for surgery in young patients usually is due to the severity of illness, [16] most surgeons prefer to divert the fecal stream proximally in these cases.

During the procedure, the distal vascular arcades of the ileum are often divided to gain length to reach the pelvis; this division predisposes the patient to ischemia. Therefore, many surgeons opt for an end ileostomy or loop ileostomy as the means of diversion. Many use the latter because of the widely held belief that takedown of a loop ileostomy is technically easier.

Data have been derived, however, that refute this assumption. On average, the operating time with loop-ileostomy takedown is 54 minutes less than that with end-ileostomy takedown. However, loop-ileostomy takedown lengthens the hospital stay, increases the time to oral feeding, and has a twofold higher wound infection rate than does end-ileostomy takedown. In addition, loop ileostomy requires significantly more outpatient stoma care and is associated with more frequent anal complications. [17]

Several centers have reported success with using laparoscopy to perform the total colectomy in combination with transanal mucosectomy to completely remove the diseased colon and rectal mucosa. [18] An ileoanal anastomosis (with or without a J pouch) can be successfully performed.

The main disadvantage of the laparoscopic approach is the increase in total operating time in comparison with open surgery. However, preliminary data suggest that laparoscopy is associated with shorter hospital stay, earlier return to normal activities and school, and improved cosmetic results. This technically demanding operation has also been successfully performed with the help of robotically assisted technology. [19]


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