61using the Rutgeerts score has not been validated as a measure of treatment response.
Intra- observer reliability using the Rutgeerts scoring system has been shown to be
fair to good with kappa between 0.43 and 0.67 [ 10 , 11 ]. The point of most discrep-
ancy likely results from the difference between i1 and i2 endoscopic appearance as
the addition of a single aphthous ulcer can upgrade an i1 lesion to i2. Despite the
limitations, due to the correlation with clinical outcomes, the Rutgeerts scoring sys-
tem has stood as the gold standard as detection of POR.
Fecal Calprotectin
While sensitive for detecting recurrence, ileocolonoscopy is an invasive and some-
what costly procedure with associated risks. As such, there have been efforts to
identify noninvasive detection methods of POR. One such method is fecal calpro-
tectin. Fecal calprotectin (fCal) is a molecule produced by mucosal leukocytes and
epithelial cells as sites of mucosal injury.
Initial studies evaluating the utility of fCal as a marker of POR were conflicting.
Lasson et al. reported there was no difference in fCal levels in postoperative CD
patients with endoscopic recurrence compared to patients with endoscopic remis-
sion at 1 year [ 12 ]. However, this study was limited by small size (n = 30). A subse-
quent, larger study of 86 asymptomatic postoperative CD patients demonstrated
significantly higher levels of fCal in patient with endoscopic recurrence (i2–i4) than
those in endoscopic remission (i0–i1) (mean ± s.e.m.: 473 ± 78 μg/g vs. 115 ± 18 μg/g;
p < 0.0001) [ 13 ]. The same study suggested a cutoff value of 100 μg/g to detect
endoscopic recurrence with a 95% sensitivity, 54% specificity, 69% positive predic-
tive value (PPV), 93% negative predictive value (NPV), and 73% overall accuracy.
In a meta-analysis of ten prospective studies totaling 613 postoperative CD patients,
Qiu et al. estimated a pooled sensitivity of 82% (95% CI 73–89%) and pooled speci-
ficity of 61% (95% CI 51–71%) for detecting endoscopic recurrence with an overall
PPV of 2.11 (95% CI 1.68–2.66) and NPV 0.29 (95% CI 0.197–0.44) [ 14 ].
Furthermore, these authors also analyzed fCal for detection of clinical recurrence
and found a pooled sensitivity of 59% (95% CI 47–71%) and pooled specificity of
88% (95% CI 80–93%) with PPV of 5.10 and NPV 0.47. This study suggests that
Table 5.2 Rutgeerts scoring system for postoperative endoscopic recurrence in the neoterminal
ileum following resection in Crohn’s disease
Rutgeerts score Endoscopic findings
i0 No aphthous ulcer
i1 ≤5 aphthous ulcers
i2 >5 aphthous lesions with normal intervening mucosa or larger skip lesions
or lesions confined to the ileocolonic anastomosis
i3 Diffuse aphthous ulcers throughout neoterminal ileum with inflamed
intervening mucosa
i4 Large ulcers (≥5 mm) with diffuse inflammation, nodules, and/or luminal
narrowing5 Use of Biologics in the Postoperative Management of Crohn’s Disease