Pce

Table 6.1. Complications of ileoanal anastomosis.

Leak Pouchitis

Small-bowel obstruction

Abscess

Stenosis

Fistula (perirectal, rectovaginal, rectovesical) Superior mesenteric artery syndrome Adenocarcinoma

Reservoir outlet obstruction (S pouch)

Various complications requiring radiologic evaluation may develop with this procedure (Table 6.1). Small-bowel obstruction, usually due to adhesions, may occur in the immediate postoperative period or anytime thereafter. Small-bowel obstruction may be simulated by normally dilated nonobstructed small bowel, however, because the small bowel may dilate with time as an accommodation to increased capacity.

Leakage most often occurs at the pouch-anal anastomosis. Less commonly, leakage may develop at the pouch suture lines. Most leaks will be small and can be treated conservatively. With the J-pouch configuration, a small amount of closed reflected ileum is often not incorporated into the pouch, which is termed the J-pouch appendage (Fig. 6.21). This appendage may leak, simulate a leak, twist, or become necrotic [13,15,16].

Figure 6.21. J-pouch appendage ("pseudoleak"). Lateral view after IPAA and J pouch shows the normal J pouch appendage extending from the posterior superior aspect of the pouch. This finding should not be confused with a leak. [Reprinted with permission from Kremers PW, Scholz FJ, Shoetz DJ. Radiology of the ileoanal reservoir. AJR Am J Roentgenol 145, (3):559-567, 1985, copyright by American Roentgen Ray Society.]

Figure 6.21. J-pouch appendage ("pseudoleak"). Lateral view after IPAA and J pouch shows the normal J pouch appendage extending from the posterior superior aspect of the pouch. This finding should not be confused with a leak. [Reprinted with permission from Kremers PW, Scholz FJ, Shoetz DJ. Radiology of the ileoanal reservoir. AJR Am J Roentgenol 145, (3):559-567, 1985, copyright by American Roentgen Ray Society.]

Pouchitis, a fairly common problem encountered after ileoanal anastomosis, occurs in up to half of patients [17]. It is a clinical condition of tenesmus and diarrhea, rarely accompanied by bleeding, fever, arthralgias, and other systemic symptoms. Pouchitis usually responds to medical therapy (antibiotics), but chronic pouchitis may lead to pouch failure. Hyperemia and ulceration may be identified endo-scopically. The cause of pouchitis is unknown, although it is more common in patients who have had surgery for ulcerative colitis than for FAPS and is more common in patients with extracolonic manifestations of ulcerative colitis [18]. No consistent radiographic findings have been found on contrast examination, although abnormal mucosal patterns with fold thickening and spiculation have been reported [19]. On CT imaging, pouchitis may be diagnosed in some cases by identification of a thickened pouch wall (>3 mm) with or without adjacent wispy densities [14]. Increased uptake in the location of the pouch may be demonstrated on 111In-labeled leukocyte scintigraphy although abscesses will have a similar pattern [14].

Stricture at the anastomotic site is the most common complication after IPAA [15]. The diagnosis can be made by digital examination or barium enema and generally can be easily treated by dilatation. Rectovaginal, perirectal, and rectovesical fistulas are other complications, reported in 6% of patients after IPAA in one series, although some of these patients later proved to have Crohn's disease [17]. Fistulas can generally be repaired surgically, although fistula formation may lead to pouch failure.

The S pouch may become obstructed and markedly enlarged secondary to stricture, kinking, or the weight of the superiorly placed reservoir on the efferent segment [13]. Surgical revision of the pouch with shortening of the efferent limb may be necessary in this circumstance. This complication appears to be unique to the S-shaped pouch.

Rarely, adenocarcinoma may develop in the retained rectal mucosa or the anal transition zone, with five cases reported on the literature [17]. One case of primary B-cell lymphoma has been reported, arising in an S pouch 8 years after IPAA [20].

The superior mesenteric artery (SMA) syndrome, an occasional complication of IPAA, has been attributed to the combination of weight loss and the reduction of the angle of origin of the SMA due to pulling of the terminal ileum down to the anus, leading to vascular compression of the duodenum [21].

Fibrous tumors, including desmoid tumors of the abdominal wall and mesenteric fibromatosis, may develop in patients with FAPS (Figs. 6.22 and 6.23). These tumors usually develop postoperatively, tend to recur locally after resection, and commonly invade bowel.

Figure 6.22. Desmoid tumor. CT scan of the abdomen after colectomy and small-bowel resection for FAPS reveals an enhancing lesion in the left rectus muscle due to a desmoid tumor.
Figure 6.23. Mesenteric fibromatosis. Films from small-bowel series in two different patients with FAPS demonstrating displacement of bowel. Invasion of bowel from fibrous tumors after colonic resection can be seen in (B).

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