Gastrointestinal Imaging Original Research

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1 Contrast Enema for Detecting nastomotic Strictures Gastrointestinal Imaging Original Research David Dolinsky 1 Marc S. Levine 1 Stephen E. Rubesin 1 Igor Laufer 1 John L. Rombeau 2 Dolinsky D, Levine MS, Rubesin SE, Laufer I, Rombeau JL Keywords: abdomen, anastomotic strictures, barium enema, fluoroscopy, gastrointestinal radiology, ileal pouch anal anastomosis, proctocolectomy, small bowel DOI: /JR Received October 17, 2006; accepted after revision January 26, M. S. Levine and S. E. Rubesin are consultants for E-Z-EM, Inc. 1 Department of Radiology, Hospital of the University of Pennsylvania, 3400 Spruce St., Philadelphia, P ddress correspondence to M. S. Levine. 2 Department of Surgery, Hospital of the University of Pennsylvania, Philadelphia, P JR 2007; 189: X/07/ merican Roentgen Ray Society Utility of Contrast Enema for Detecting nastomotic Strictures fter Total Proctocolectomy and Ileal Pouch nal nastomosis OJECTIVE. The purpose of our study was to determine the utility of contrast enemas for detecting clinically relevant anastomotic strictures after total proctocolectomy and ileal pouch anal anastomosis and to facilitate management by defining a critical anastomotic caliber at or below which obstruction is likely to develop after ileostomy closure. MTERILS ND METHODS. Our radiology database revealed 42 patients with contrast enemas after total proctocolectomy and ileal pouch anal anastomosis who fulfilled our exclusion criteria. The initial postoperative contrast enemas were reviewed blindly to determine the diameter of the ileoanal anastomosis. The diagnosis of a stricture was made only if the patient had signs of intestinal obstruction after ileostomy closure with confirmation on follow-up contrast enema or sigmoidoscopy and clinical improvement after anastomotic dilatation. The data were then correlated to determine if there was a critical anastomotic caliber at or below which such strictures were likely to develop. Using this threshold value, the sensitivity and specificity of routine contrast enemas for detecting clinically relevant anastomotic strictures were then determined. RESULTS. Six (14%) of the 42 patients who underwent total proctocolectomy and ileal pouch anal anastomosis had strictures at the ileoanal anastomosis on contrast enemas. The mean diameter of the anastomosis was 5.8 mm in the six patients with anastomotic strictures versus 15 mm in the 36 patients without strictures (p = ). If an anastomotic diameter of 8 mm is defined as the critical caliber at or below which clinically relevant strictures are present, the sensitivity of contrast enemas for detecting strictures at the ileoanal anastomosis was 100% (six of six patients) and the specificity was 92% (33 of 36 patients). CONCLUSION. Routine contrast enema after total proctocolectomy and ileal pouch anal anastomosis is a sensitive test for detecting clinically relevant strictures at the ileoanal anastomosis when an anastomotic diameter of 8 mm or less is used as the threshold value for diagnosing these strictures. Such patients may need dilatation procedures to decrease the risk of anastomotic obstruction after ileostomy closure. otal proctocolectomy and construction of an ileal pouch anal T anastomosis is a well-established surgical treatment for ulcerative colitis and familial adenomatous polyposis syndrome [1, 2]. lthough the procedure is occasionally performed as a one-stage operation [3], most surgeons favor a two-stage approach [1, 2]; the first stage consists of a total abdominal proctocolectomy, construction of an ileal J-pouch, anastomosis of the pouch to the anal canal, and a temporary diverting loop ileostomy. fter the various anastomoses have been give time to heal (about 12 weeks at our institution), the patient undergoes the second stage of the procedure in which the diverting ileostomy is taken down and the fecal stream is reintroduced to the ileal pouch and ileoanal anastomosis. Total proctocolectomy and ileal pouch anal anastomosis may be associated with a variety of early and late complications, including anastomotic leaks, pelvic abscesses, fistulas, pouchitis, strictures, and small-bowel obstruction [4 7]. Previous studies have shown that contrast enema examinations are useful for detecting many of these complications before takedown of the diverting ileostomy, particularly asymptomatic leaks from the ileal pouch or ileoanal anastomosis [8 12]. These contrast enemas are more readily performed as retrograde studies via the anus than as antegrade studies via the distal limb of the diverting loop ileostomy [13, 14]. JR:189, July

2 C Fig year-old woman who underwent normal water-soluble contrast enema after total proctocolectomy and ileal C, Lateral (), frontal (), and steep oblique (C) spot images of pelvis before takedown of diverting ileostomy show normal appearance of ileal pouch and ileoanal anastomosis (white arrows), which has smooth, symmetric margins and diameter of 20 mm. Note dilatation of anal canal distal to anastomosis, a common finding on these studies. In and C, tip of catheter (black arrows) is in ileal pouch, whereas in, tip of catheter (black arrow) is just distal to ileoanal anastomosis. When strictures are found at the ileoanal anastomosis on contrast enema or digital rectal examination, the strictures can be dilated at or before ileostomy closure, decreasing the risk of subsequent anastomotic obstruction [15]. To our knowledge, however, no studies in the radiology literature have identified the critical anastomotic caliber below which anastomotic obstruction is likely to develop. The purpose of our study, therefore, was to determine the utility of routine contrast enema examinations for detecting clinically relevant anastomotic strictures after total proctocolectomy and ileal pouch anal anastomosis and to facilitate patient management by defining a critical caliber of the ileoanal anastomosis at or below which anastomotic obstruction is likely to develop after ileostomy closure. Materials and Methods Patient Population computerized search of the radiology database at our university hospital revealed 103 patients who had contrast enema examinations after total proctocolectomy and ileal pouch anal anastomosis during a 7.5-year period from January 1998 to June Sixty-one patients were excluded from analysis for one of the following reasons: medical records were not available for review, the patient did not have a routine postoperative contrast enema examination before takedown of the diverting ileostomy (i.e., the studies were performed for suspected complications), the diverting ileostomy had not yet been taken down, or a dilatation procedure had been performed at the time of ileostomy closure. The remaining 42 patients composed our study group. The mean age of the patients was 44 years (age range, years). Twenty patients (48%) were men and 22 (52%) were women. Thirty-eight patients (90%) underwent surgery for ulcerative colitis and four (10%) for familial adenomatous polyposis syndrome. Contrast Enema Examinations The 42 patients in our study group had a total of 51 contrast enema examinations (nine patients also had examinations after ileostomy closure). The studies were performed by retrograde administration of a water-soluble contrast agent (Gastroview [diatrizoate meglumine and diatrizoate sodium], Mallinckrodt; Hypaque [diatrizoate sodium], Nycomed) via a 22-French Foley catheter inserted through the anus into the anal canal, ileal pouch, or both at various times during the examination (depending on the preferences of the examiner). Using digital fluoroscopic equipment (Diagnost 76, Philips Medical Systems; Sireskop SD, Siemens Medical Solutions), spot images of the anal canal, ileoanal anastomosis, and ileal pouch were routinely obtained with the patient in lateral, frontal, and oblique positions (Fig. 1). ll of the studies were performed by residents, fellows, or one of three attending gastrointestinal radiologists, and all were interpreted by one of the attending radiologists. Study Design Medical and surgical records from these 42 patients were reviewed to determine whether the patients had clinical signs or symptoms of intestinal obstruction (including constipation, small-caliber stools, nausea or vomiting, tenesmus, and pelvic pain) after takedown of the diverting ileostomy, whether the patients with obstructive symptoms after ileostomy closure underwent sigmoidoscopic examinations that revealed narrowing at the ileoanal anastomosis, and whether subsequent digital or endoscopic balloon dilatation of the anastomosis resulted in clinical improvement. The initial postoperative contrast enema examinations in these 42 patients were reviewed in consensus by two of the authors (both experienced gastrointestinal radiologists) who were blinded to clinical presentation, treatment, and patient course. The studies were evaluated to determine the diameter and length of the ileoanal anastomosis (magnification was accounted for on the radiographs by using the known diameter of the 22- French Foley catheter as a reference standard on the images). Nine repeat contrast enema examinations after ileostomy closure were also reviewed for radiographic signs of obstruction at the ileoanal anastomosis, including pouch dilatation, delayed emptying of the pouch (this one parameter was assessed by reviewing the original radiology reports), excessive debris in the pouch, and smallbowel dilatation proximal to the pouch. The diagnosis of a clinically relevant stricture at the ileoanal anastomosis was made only if the patient had signs or symptoms of intestinal obstruction after ileostomy closure, with confirmation of the stricture either on a repeat contrast enema examination showing radiographic signs of anastomotic obstruction (as previously discussed) or on follow-up sigmoidoscopy showing narrowing at the ileoanal anastomosis and subsequent clinical improvement after digital or endoscopic balloon dilatation of the anastomosis. 26 JR:189, July 2007

3 Contrast Enema for Detecting nastomotic Strictures Fig year-old woman with stricture at ileoanal anastomosis after total proctocolectomy and ileal, Frontal spot image of pelvis from water-soluble contrast enema before closure of diverting ileostomy shows stricture at ileoanal anastomosis (white arrow), which has diameter of 8 mm. Note how tip of catheter (black arrow) is just distal to ileoanal anastomosis., Frontal spot image of pelvis from repeat water-soluble contrast enema after takedown of ileostomy shows continued stricture at ileoanal anastomosis (arrow) with marked dilatation of ileal pouch and reflux of contrast material into dilated loops of distal ileum. This patient presented with symptoms of obstruction (nausea, vomiting, and abdominal distention) after ileostomy closure. The study population was then stratified into two groups based on the presence or absence of a stricture at the ileoanal anastomosis and correlated with the imaging data to determine if there was a critical anastomotic caliber at or below which such strictures were likely to develop. Using this threshold value, the sensitivity and specificity of the contrast enema examination for detecting anastomotic strictures were determined. Fig year-old woman with stricture at ileoanal anastomosis after total proctocolectomy and ileal, Lateral spot image of pelvis from water-soluble contrast enema before closure of diverting ileostomy shows stricture at ileoanal anastomosis (white arrow), which has diameter of 4 mm. Note how tip of catheter (black arrow) is distal to ileoanal anastomosis., Lateral spot image of pelvis from repeat water-soluble contrast enema after takedown of ileostomy shows continued stricture at ileoanal anastomosis (arrow), with dilatation of ileal pouch and retained debris in pouch. This patient presented with symptoms of obstruction (constipation and pelvic pain) after ileostomy closure. The location of the catheter tip in the ileal pouch, anal canal, or both during the examination was also determined in patients with and without anastomotic strictures. statistical analysis of the data was performed using a Wilcoxon s rank sum test (JMP IN, version 4.0.3; SS Institute). Our institutional review board approved all aspects of this retrospective study and did not require informed consent from any patients included in our study. Results Six (14%) of the 42 patients who underwent total proctocolectomy and ileal pouch anal anastomosis were found to have clinically relevant strictures at the ileoanal anastomosis on routine contrast enema examinations before ileostomy closure (Figs. 2 and 3). The strictures were confirmed by repeat contrast enema studies after ileostomy closure showing radiographic signs of anastomotic obstruction in three patients (Figs. 2 and 3) and by follow-up sigmoidoscopy showing anastomotic narrowing with subsequent clinical improvement after endoscopic balloon dilatation procedures in three. Five (83%) of the six patients with anastomotic strictures had undergone total proctocolectomy and ileal pouch anal anastomosis for ulcerative colitis and one (17%) for a polyposis syndrome. The mean diameter of the ileoanal anastomosis was 5.8 mm (range, 4 8 mm) in the six patients with clinically relevant anastomotic strictures versus a mean diameter of 15 mm (range, 5 30 mm) in the 36 patients without strictures. The mean anastomotic diameter in the six patients with strictures was significantly smaller than that in the 36 patients without strictures (p = ). If an anastomotic diameter of 8 mm is defined as the critical caliber at or below which clinically relevant strictures are thought to be present, the sensitivity of routine contrast enema examinations for detecting such strictures at the ileoanal anastomosis before ileostomy closure was 100% (six of six patients) (Figs. 2 and 3) and the specificity was 92% (33 of 36 patients), with three false-positive studies for strictures (Fig. 4). The mean length of the ileoanal anastomosis was 1.9 mm (range, mm) in the six patients with anastomotic strictures versus a mean length of 2.8 mm (range, 2 10 mm) in the 36 patients without strictures. The mean anastomotic length in the six patients with strictures was significantly smaller than that in the 36 patients without strictures (p = 0.03). The contrast enema examinations were performed with the catheter tip in the anal canal in five (83%) of the six patients with strictures at the ileoanal anastomosis and in both the anal canal and ileal pouch in one (17%). Thus, no patients with anastomotic strictures had examinations performed with the catheter tip solely in the ileal pouch. In contrast, the contrast enema examinations were performed with the catheter tip in the anal canal in 18 (50%) of the 36 patients without anastomotic strictures, in the ileal pouch in 16 (44%), and in both the anal canal and ileal pouch in two (6%). JR:189, July

4 Fig year-old man with false-positive stricture at ileoanal anastomosis after total proctocolectomy and ileal and, Lateral () and frontal () spot images of pelvis from water-soluble contrast enema before takedown of diverting ileostomy show apparent stricture at ileoanal anastomosis (arrows), which has diameter of 8 mm. However, patient had no clinical signs of obstruction after ileostomy closure, and no further imaging studies were performed. This was one of three false-positive anastomotic strictures in our study. Discussion Total proctocolectomy with construction of an ileal pouch anal anastomosis is currently accepted as definitive treatment for ulcerative colitis and familial adenomatous polyposis syndrome. The procedure is generally performed as a two-stage operation, with construction of a temporary diverting ileostomy to allow a period of healing before reintroducing the fecal stream to the ileal pouch and ileoanal anastomosis [1, 2]. In our study, the prevalence of strictures at the ileoanal anastomosis after total proctocolectomy and ileal pouch anal anastomosis was 14%. In other studies, the prevalence of strictures has ranged from 8% to 14% [5 7, 15, 16]. To our knowledge, however, no previous studies have shown the utility of routine contrast enema examinations for detecting clinically relevant anastomotic strictures before ileostomy closure. In our study, the mean diameter of the ileoanal anastomosis in the six patients with strictures was 5.8 mm versus a mean diameter of 15 mm in the 36 patients without strictures. In one previous study, the mean anastomotic diameter in patients without clinical signs of strictures after ileal pouch anal anastomosis also was 15 mm [10]. Unlike the earlier study, however, the mean diameter of the ileoanal anastomosis in our six patients with anastomotic strictures was significantly smaller than that in the 36 patients without strictures (p = ). More important, when an anastomotic diameter of 8 mm was used as the critical caliber at or below which anastomotic obstruction was likely to develop after ileostomy closure, our sensitivity for detecting clinically relevant strictures at the ileoanal anastomosis was 100% (six of six patients) (Figs. 2 and 3) and our specificity was 92% (33 of 36 patients). lthough our threshold value of 8 mm resulted in three false-positive examinations for strictures (Fig. 4), there were no false-negatives because all symptomatic patients with strictures had anastomotic diameters of 8 mm or less. Endoscopic balloon dilatation procedures for strictures at the ileoanal anastomosis are generally safe, effective, and well tolerated [17], whereas anastomotic obstruction after ileostomy closure is associated with substantial patient morbidity. Our ability to detect clinically relevant strictures at the ileoanal anastomosis with high sensitivity therefore has important implications for patient management because it could decrease the risk of intestinal obstruction after takedown of the diverting ileostomy by identifying those patients who are more likely to benefit from a dilatation procedure at or before ileostomy closure. Some authors advocate digital rectal examination rather than contrast enema for detecting anastomotic strictures before ileostomy closure because of the accessibility of the anastomosis to the examiner s finger and the ease of performing this examination [14, 15]. Digital rectal examination is a relatively subjective test of stricture formation, however, and depending on the size of the examiner s finger, the critical anastomotic caliber below which obstruction is considered likely after ileostomy closure may vary. In contrast, our experience suggests that the contrast enema examination is a more objective and reliable test for detecting strictures at the ileoanal anastomosis when a fixed threshold diameter is used. ll six patients with anastomotic strictures on contrast enema examinations had their studies performed with the catheter tip in the anal canal (one patient had the catheter tip in the anal canal and ileal pouch at various times during the procedure), whereas 16 (44%) of the 36 patients without strictures had their studies performed with the catheter tip in the ileal pouch. It therefore is tempting to suggest that strictures are more likely to be detected at the ileoanal anastomosis when the catheter is positioned with its tip in the anal canal at or near the site of anastomotic narrowing. On the other hand, these findings may reflect a bias for performing the examination with the catheter tip in the anal canal in patients with anastomotic strictures in whom it is more difficult to advance the catheter into the ileal pouch. controlled prospective study is needed to determine optimal placement of the catheter tip for these examinations. Our investigation has the inherent limitations of a retrospective study, including selection bias and interpretation bias. Our analysis is also limited by the need to define clinically relevant strictures at the ileoanal anastomosis on the basis of subjective signs and symptoms of anastomotic obstruction after takedown of the diverting ileostomy because there is no uniform gold standard for the diagnosis of such strictures. The lack of repeat contrast enema examinations after ileostomy closure in many patients is another weakness of our study. In conclusion, our experience suggests that routine contrast enema examination after total proctocolectomy and ileal pouch anal anastomosis is a sensitive test for detecting clinically relevant strictures at the ileoanal anastomosis when an anastomotic diameter of 8 mm or less is used as the threshold value for diagnosing these strictures. Such patients may need dilatation procedures to widen the anastomosis and decrease the risk of anastomotic obstruction after ileostomy closure. References 1. Parks G, Nicholls RJ. Proctocolectomy without ileostomy for ulcerative colitis. MJ 1978; 2: Utsunomiya J, Iwama T, Imajo M, et al. Total colectomy, mucosal proctectomy, and ileoanal anasto- 28 JR:189, July 2007

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