Re-evaluation of the Clinical Significance of the Fatigue Rate Index in the External Anal Sphincter

PURPOSE: The fatigue rate index (FRI) has been developed to access sustained voluntary contraction of the external anal sphincter. This study is designed to refine the technical aspects of measuring the FRI and to re-evaluate its clinical significance. METHODS: Thirty-eight patients with fecal incontinence (19 males, 19 females) and 37 (21 males, 16 females) controls were studied. Anal manometry was performed by using standard protocols. Fatigue was measured over a 20-sec squeeze at a high-pressure zone. The FRI was calculated from the maximum squeeze pressure (MXSP) and the fatigue rate. For the accuracy of the calculation, the mean resting pressure (MRP) was calibrated to zero before the metric procedure, representative segments of the calculation were selectively designated as those denoting sustained squeeze, and representative channels were designated from among 8 channels by using 3 or more of those showing typical sustaining-pressure curves. RESULTS: No difference in demographic factors was detected between the two groups. Basic manometric parameters were significantly different between the two groups (MRP, 29.4+/-21.3 vs. 44.4+/-17.8 mmHg, P=0.0015; MXSP, 205.9+/-98.0 vs. 274.2+/-106.5 mmHg, P=0.0051). The FRI was also significantly different (29.8+/-14.3 vs. 86.3+/-127.1 sec, P=0.0108). The areas under the receptor operating-characteristic curves for the MRP, the MXSP, and the FRI were 0.72, 0.69, and 0.84, respectively. The sensitivity and the specificity of the FRI for detecting fecal incontinence were 80% and 65% at 40 sec as a cut-off point. CONCLUSION: The FRI was proven to be more accurate than the MRP and the MXSP in detecting incontinence. With adequate modifications of the measuring method, measurement of the FRI could be done more easily and conveniently, but its cut-off point for detecting fecal incontinence was lower than previously reported.

Hyperplastic Polyposis Associated with Two Synchronous Colon Cancers

Hyperplastic polyps are common large-bowel tumors, are frequently detected in middle- to old- aged people, and usually are minuscule lesions in the distal colon and rectum. Most hyperplastic polyps have no malignant potential, but recent studies suggest that some hyperplastic polyps can progress to colorectal cancers, possibly by the so-called serrated pathway. Hyperplastic polyposis is a rare syndrome characterized by multiple hyperplastic polyps, primarily in the proximal colon. Different from sporadic hyperplastic polyps, hyperplastic polyposis is alleged to have high potential for malignancy because patients with this syndrome may frequently have conventional adenomas, serrated adenomas, and adenocarcinomas. We report the case of a patient with hyperplastic polyposis, who had two synchronous colon cancers, as well as sessile serrated adenomas and tubular adenomas.