Fatigue rate index as a new measurement of external sphincter function

Diseases of the Colon & Rectum (Impact Factor: 3.2). 02/1998; 41(3):336-343. DOI: 10.1007/BF02237488

ABSTRACT PURPOSE: Assessment of sustained voluntary contraction of the external sphincter is helpful in evaluating the patient who has a defecation disorder on presentation. A new index of external sphincter function is described. METHOD: A prospective registry of patients referred for computerized anal manometry using standard protocols was reviewed. Patients were grouped by primary symptoms; those with overlapping complaints were excluded. The rate of fatigue, defined as the change in stationary squeeze over a 40-second period of voluntary contraction, was calculated by linear regression analysis. Fatigue rate index, a calculated measure of time necessary for the external sphincter to become completely fatigued, was determined to permit comparison of external sphincter fatigue in patients with different complaints. RESULTS: Twenty-six healthy volunteers (15 women; mean age, 45 years), 33 patients with a primary complaint of anal seepage (13 women; mean age, 53 years), 75 patients with gross incontinence (61 women; mean age, 53 years), and 49 patients with severe constipation (41 women; mean age, 45 years) were evaluated. Mean resting and squeeze pressures were 55 mmHg and 107 mmHg for volunteers, 37 mmHg and 97 mmHg for patients with seepage, 30 mmHg and 49 mmHg for incontinent patients, and 56 mmHg and 93 mmHg for constipated patients. Pudendal neuropathy, as evidenced by a prolonged pudendal nerve terminal motor latency (>2.4 ms), was identified in 13 percent of volunteers, 32 percent of patients with seepage, 54 percent of incontinent patients, and 38 percent of constipated patients. Mean fatigue rate index was 3.3 minutes for volunteers, 2.3 minutes for seepage patients, 1.5 minutes for incontinent patients, and 2.8 minutes for constipated patients. Compared with volunteers and patients with seepage, the incontinent patients had a significantly shorter fatigue rate index (P<0.05; Student'st-test), which was independent of the variations in resting pressure (P<0.05; two-way analysis of variance). CONCLUSION: The external anal sphincter is normally subject to fatigue. Patients with worsening degrees of incontinence have a predictably lower fatigue rate index. Fatigue rate index is a simple measure of external sphincter integrity, which may be used in assessment of sphincter function and future treatment protocols.

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    ABSTRACT: Fecal incontinence (FI) and urgency are prevalent symptoms in patients with inflammatory bowel diseases (IBD). It is unclear which factors determine their severity. We evaluated associations of clinical activity, anorectal motility, and endoanal sonography with FI severity in IBD. Fifty-eight consecutive IBD patients and 14 healthy volunteers participated in a cross-sectional, tertiary-center study. Active disease was defined as Crohn's disease activity index ≥ 150 and as simple clinical colitis index > 2. We assessed anal pressures and fatigue rate index (FRI) of the external anal sphincter (EAS) by manometry, rectal compliance and sensitivity by balloon distension, and sphincter defects by endoanal ultrasound. Significant bivariate associations between these parameters and the fecal incontinence severity scale (FISS) were evaluated in multivariate analysis. Twenty-seven patients (47%) reported urgency, 13 of which (22%) reported FI. Defects of the internal anal sphincter (IAS) and the EAS were diagnosed in 14 (24%) and 13 patients (22%), respectively. Patients had significantly lower rectal compliance and FRI compared with controls. FISS demonstrated significant bivariate associations with clinical disease activity (P = 0.0115), FRI (P = 0.0018), sonographic IAS and EAS defects (P < 0.0001 and 0.0059), rectal compliance (P = 0.0001), and volume at the threshold of a constant urge (Vurge, P = 0.0002). In multivariate analysis, FISS was associated with clinical disease activity (P = 0.0325), FRI (P = 0.0367), Vurge (P = 0.0091), and sonographic IAS defect(s) (P = 0.0008). The derived model explained 62% of the variance in FISS (P < 0.0001). Clinical disease activity and manometric and sonographic anorectal parameters are associated with FI severity in IBD. Prospective studies are warranted to evaluate their predictive value in continence outcomes.
    Inflammatory Bowel Diseases 08/2013; DOI:10.1097/MIB.0b013e3182a2952b · 5.48 Impact Factor
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    ABSTRACT: 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.
    Journal of the Korean Society of Coloproctology 01/2009; 25(2). DOI:10.3393/jksc.2009.25.2.75
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    ABSTRACT: Anal manometry is one of the most commonly used tests to evaluate fecal continence function. Advanced pressure parameters of the tests, such as fatigue rate index (FRI), resting rectoanal pressure gradient (RPG), cough index (CI), and radial asymmetry (RA) are recently devised to make up the inaccuracy of conventional parameters, but without solid verification. The object of this study is to investigate such parameters including conventional ones in incontinent patients compared with those in controls and to determine the significance of each parameter.
    Journal of the Korean Society of Coloproctology 01/2009; 25(1). DOI:10.3393/jksc.2009.25.1.20