Fatigue rate index as a new measurement of external sphincter function
Diseases of the Colon & Rectum (Impact Factor: 3.75). 02/1998; 41(3):336-343. DOI: 10.1007/BF02237488
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.
Chapter: Physiologic Testing[Show abstract] [Hide abstract]
ABSTRACT: Physiologic testing has been used to assess pelvic floor and anorectal disorders for the past 35 years, but only in the past two decades has this testing become of value for clinical use. These physiologic tests are performed in conjunction with a history, diary of the disorder, physical examination, endoscopy, and often imaging studies. Physiologic tests have provided or confirmed a diagnosis in 75% of patients with constipation, 66% of patients with incontinence, and 42% of patients with chronic anorectal pain according to one study.
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ABSTRACT: PURPOSE: Neosphincter procedures may prove to be the treatment of choice for patients with neuropathic fecal incontinence but are rarely proposed for milder forms of the disease. Biofeedback may prove beneficial to these patients but is yet unproven. The objectives of this study were to develop a method of performing biofeedback using transanal ultrasound to teach the patient to contract repetitively and to determine biologic measures of sphincter function using transanal ultrasound in healthy and incontinent patients. METHODS: Initial uncontrolled studies were performed to determine the compliance, normal values, biologic measures of external sphincter strength (isotonic and isometric fatigue times), and early efficacy data using continence scores and visual analog scale scores. RESULTS: Forty-four patients were assessed during three months, with relative improvements in continence scores (St. Mark's Hospital, 40 percent; Pescatori, 20 percent) and patient and investigator visual analog scale scores (38 percent for both) and measurable increase in biologic fatigue times measured by transanal ultrasound. CONCLUSIONS: Transanal ultrasound seems to be a method of teaching external sphincter contraction and measuring sphincter strength with good initial compliance. Clinically and statistically significant improvements in incontinence scores, visual analog scale scores, and biologic strength of the external sphincter were detected in the short-term follow-up with uncontrolled data. The randomized, controlled trial that we have begun will either confirm or refute these results.
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ABSTRACT: "Fecal incontinence" is defined as the involuntary loss of stool at any time of life after toilet training. It is a socially and psychologically devastating condition for patients and their families, and a topic which both patients and physicians are reluctant to approach. Although the true prevalence of fecal incontinence is unknown, studies have reported it to be as high as 2. 2% in the general population, with significantly higher rates among nursing home residents and hospitalized elderly. Risk factors include advancing age, female gender and multiparity. An understanding of pelvic floor anatomy and physiology is required to appreciate how diverse medical conditions can affect mechanisms involved in normal continence. The rectum serves as a storage reservoir until elimination can take place at a socially acceptable time and place. The pelvic floor muscles help to regulate the defecatory process and maintain continence. These muscles include the internal anal sphincter, the external anal sphincter and the puborectalis muscle. Each muscle contributes to normal continence, although the relative importance of each is controversial. Neurologic integrity and sensation are also key factors. Conditions associated with fecal incontinence include diarrheal states, fecal impaction, idiopathic neurologic injury, surgical and obstetric injury, pelvic trauma, collagen vascular disease, and neurologic impairment related to stroke, diabetes, or multiple sclerosis. Evaluation of the patient with fecal incontinence includes a directed history and physical examination, with particular attention paid to integrity of the perineum and rectum, and a complete neurologic evaluation. Diagnostic tools such as stool studies, anorectal manometry, defecography, electromyography, pudendal nerve conduction, and endoanal ultrasound may be employed in an outpatient setting. Fecal incontinence may be treated conservatively by employing such methods as dietary restriction, stool bulking agents, and biofeedback. Surgery may be the best option for cases refractory to medical treatment, or for those patients with rectocele or obstetrical injury. In this article, we review the presentation, epidemiology, pathophysiology, and etiology of fecal incontinence. Evaluation, including key components of directed history and physical examination, and the appropriate use of diagnostic studies and indications for treatment options are also addressed.
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