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| 번호 | 제목 | 등록일 | 조회수 |
|---|---|---|---|
| 120 | Predictors of Response to Biofeedback Treatment in Anal Incontinence [2003년 9월 DCR] | 2011-11-17 | 3743 |
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Xose Ferna´ndez-Fraga, M.D., Fernando Azpiroz, M.D., Anna Aparici, R.N.,Maite Casaus, R.N., Juan-R Malagelada, M.D.
From the Digestive System Research Unit, University Hospital Vall d’Hebron, Autonomous University of Barcelona, Barcelona, Spain PURPOSE: Biofeedback is considered an effective treatment for anal incontinence, but a substantial proportion of patients fails to improve. The purpose of this study was to identify the key predictors of outcome.
METHODS: We retrospectively analyzed the clinical and physiologic data of 145 patients consecutively treated in our unit for anal incontinence by biofeedback. Clinical evaluation was performed by means of a structured questionnaire that included previous history, symptoms of incontinence, and bowel habit. Anorectal evaluation measured anal pressure profiles, neural reflexes, defecatory dynamics, rectal compliance, and rectal sensitivity. Biofeedback treatment was performed by a manometric technique with reinforcement sessions scheduled every three months and daily exercising at home. Six months after the onset of biofeedback treatment the clinical response was evaluated as good (improvement
of incontinence) or poor (no improvement or worsening). RESULTS: Of 126 patients (104 female; age range, 17–82 years) with at least six-month follow-up, 84 percent had a good response to treatment. By univariate analysis, several factors, such as age, history of constipation, abnormal defecatory maneuver, and rectal compliance, were significantly related to treatment response, but by multivariate logistic regression only age and defecatory maneuver were independent predictors of the response. The association of both factors provided the best sensitivity and specificity; 48 percent of patients younger than age 55 years and with abnormal defecatory maneuver had negative response to treatment, whereas 96 percent of patients age 55 years or older with normal defecatory maneuver had a positive response. CONCLUSION: In patients with anal incontinence scheduled for biofeedback treatment, potential alterations of defecation should be first searched for and corrected, particularly in younger patients. Fecal incontinence consists in the uncontrolled passage of rectal content through the anus that often becomes a chronic incapacitating disorder, severely impairing patients’ quality of life. Furthermore,
fecal incontinence has important socioeconomic repercussions. For instance, it is the second most common cause of institutionalization in the elderly. Biofeedback is believed to be an effective treatment of incontinence, particularly in patients without major sphincteric damage susceptible of surgical repair. Reported improvement rates range between 50 and 92 percent,but it is recognized that some patients fail to improve. The purpose of this study was to identify clinicophysiologic factors that determine the outcome to
biofeedback treatment in patients with anal incontinence. We retrospectively analyzed the clinical and manometric data obtained in a large cohort of patients treated in our unit for fecal incontinence by means of biofeedback, with a follow-up longer than six months. Evaluation of Anorectal Function
Anorectal function was evaluated by a series of consecutive tests performed with the patients in lateral decubitus position. The following tests were performed.
Anal Manometry. Contraction of anal sphincters was evaluated using a low compliance manometric
perfusion system (0.1 ml/min perfusion rate) and a four-radial-lumen polyvinyl catheter (2.4 mm OD, ES4X®, Arndorfer Medical Specialties, Greendale, WI) by a stationary pull-thorough technique at 1-cm steps. The tonic contraction of the internal anal sphincter was evaluated by the basal anal pressures (at each level of the anal canal mean radial pressure referenced to intrarectal pressure), and the phasic contraction of the external anal sphincter by the squeeze pressures (pressure increment from basal at each level). The length of the anal canal from orad (basal pressure >/= 10 mmHg) to caudad (anal verge) was measured. Neural Reflexes. Reflex responses were evaluated using a five-lumen polyvinyl catheter (4.8 mm outside
diameter, ARM®, Arndorfer Medical Specialties) with four manometric ports 1-cm apart and a distal tip latex balloon located 5 mm from the distal port. The rectoanal inhibitory reflex was trigged by inflation of the rectal balloon with air as follows: phasic rectal distensions of 10-second durations were performed at 1-minute interval and in 10-ml increments while measuring the reflex relaxation of the internal anal sphincter (anal pressure drop). This is an intrinsic reflex driven by fibers in the myenteric plexus. Abnormal reflex was defined as absent relaxation with distending volumes up to the level of discomfort. The cough reflex was evaluated with the intrarectal balloon inflated with 25 ml of air. Patients were asked to cough, and the reflex contraction of the external anal sphincter (anal pressure increment) in response to the abdominal compression (intrarectal pressure peak) was measured. This is a sacral reflex driven by the pudendal nerves. Abnormal cough reflex was defined as anal pressure peak lower than both the intraabdominal pressure peak and the voluntary squeeze pressure. Defecatory Maneuver. The dynamics of defecation was studied by means of a manometric technique. The same catheter as described for evaluation of neural reflexes was used with the intrarectal balloon inflated with 25 ml of air and the manometric ports located in the anal canal. Patients were asked to
attempt defecation, and both the abdominal compression (intrarectal pressure increment) and the anal relaxation (anal pressure drop) during straining were measured. Normally the four manometric ports exteriorize recording atmospheric pressure. Abnormal defecatory maneuver was defined as incomplete anal relaxation during straining (pressure above atmospheric in one or more proximal ports). Rectal Compliance and Sensitivity. An electronic barostat was connected by a double-lumen polyvinyl
tube (12-F, Argyle®, Sherwood Medical, Tullamore, Ireland) to a flaccid, oversized polyethylene bag (600 ml capacity, 28-cm maximal perimeter) introduced into the rectum. Rectal distention was produced at fixed pressure levels in 4 mmHg stepwise increments every 15 seconds while measuring intrarectal pressure and subjective sensations. Rectal compliance was expressed as the intrarectal volume at 20 mmHg and rectal sensitivity as the pressure levels that induced first sensation and urge to evacuate. Biofeedback Treatment
Biofeedback treatment of anal incontinence was primarily directed toward anoperineal striated muscle
strengthening, but sensory training and synchronization of rectoanal reflexes were not targeted. In patients with abnormal defecatory maneuver, no specific biofeedback treatment for impaired defecation was attempted, because the primary complaint and referral reason was incontinence, and no patient presented fecal retention and overflow incontinence. Biofeedback was performed by means of a manometric technique. Using the above-mentioned five-lumen tube (intrarectal balloon plus four anal recording ports), intrarectal and anal pressures were recorded and displayed on a monitor in view of the patients. Under visual control, the patients were instructed to squeeze for five seconds trying to increase anal pressure as much as possible without abdominal compression, i.e., without intrarectal pressure increments. Each session lasted 30 to 45 minutes. Patients then were instructed to exercise twice daily for ten minutes, alternating five-second squeeze and ten-second resting intervals. After one to three initial sessions, reinforcement sessions were scheduled at three-month intervals. DISCUSSION
By performing a logistic regression analysis of multiple clinical and physiologic parameters in a large
population of incontinent patients, we have for the first time identified two independent factors, the defecatory maneuver and age, that determine the longterm response of anal incontinence to strengthening biofeedback treatment. We acknowledge the subjective outcome measured in our study, but nevertheless, the response rate to treatment was similar as in previous studies with different outcome measures. The normal defecatory maneuver entails a voluntary abdominal compression associated to anoperineal
relaxation that allows complete rectal evacuation. In the present study we have found, first, that despite its apparently paradoxical coexistence with incontinence, a large proportion of such patients have an abnormal defecatory maneuver that may not be even associated to constipation. Second, this abnormal defecatory maneuver is an independent predictor of the response to strengthening biofeedback treatment in these patients. The defecatory maneuver in the present study was evaluated by manometry, because it is a well-established technique; however, other tests, i.e., electromyography, balloon expulsion, and defecography, also have been used. The correlation of results from different tests is variable (70 percent concordance between manometry and electromyography, and 61 percent between manometry and defecography), in part because not exactly the same aspects are evaluated. Furthermore, it remains debatable to what extent an abnormal maneuver constitutes a reliable indicator of altered physiology or it represents behavioral reaction to laboratory environmental conditions. However, the fact that an abnormal defecatory maneuver was altogether associated to poor response to treatment, constipation, and large rectal compliance suggests an underlying physiologic abnormality. Impaired defecatory maneuver may produce functional outlet obstruction and constipation. Furthermore,
if the anus does not relax properly, rectal evacuation may require a stronger abdominal compression, which may lead to perineal damage. Hence, we speculate that impaired defecatory maneuver may be a cause of incontinence via to anoperineal damage, and this may explain their association. Constipation was associated to poor response to treatment, but only in relation to impaired defecation.
However, in the present and previous studies, some patients with an impaired defecatory maneuver do not complain of constipation. In such patients it remains unclear whether the defecation test is unreliable, i.e., false positive, or whether the defecatory dysfunction, albeit subclinical, may still lead to perineal damage and long-term complications. The analysis of the situation is particularly challenging, because constipation is clinically defined both by objective signs, such as reduced frequency and increased stool consistency, and by subjective sensations, such as excessive straining and anal blockade, and patients with lifelong constipation may not be even aware that they are straining inappropriately and excessively. The poor response of anal incontinence to biofeedback therapy in the presence of impaired defecatory
maneuver may involve two different mechanisms. First, normal defecation completely evacuates the rectum, but an impaired defecatory maneuver is associated with incomplete rectal evacuation, and rectal residues may leak if anal closure fails. Second, the pelvic floor stress produced by excessive straining may counterbalance the progress of muscular rehabilitation. In the present study, impaired defecatory maneuver was not specifically treated, because no patient had obvious overflow incontinence and clinical constipation was absent or just a minor complaint with respect to incontinence. Increased rectal capacity was related to poor treatment outcome, but this also was associated to impaired defecatory maneuver. On the other hand, patients with reduced rectal capacity had higher incidence of unnoticed incontinence episodes. Impaired rectal reservoir associated to impaired anal closure conceivably determined this effect.
In our study we also found that young age negatively affected the responsiveness of anal incontinence
to treatment. Using the mean age of our incontinent population as cutoff, we found that patients younger than age 55 years did worse than older ones. A similar association has been previously reported. Such inverse relation between age and treatment response is intriguing. It could be simply related to the unfulfilled higher expectations of younger patients. It also may be that subjective improvement in anal incontinence is heavily influenced by nonspecific effects on patients’ well-being and confidence. As previously reported, neither rectal sensitivity nor sphincteric activity determined the response to treatment in our study group. However, we emphasize that none of our patients had known neurologic
disorders, severe rectal hypoesthesia, or major muscular disruption with anal asymmetry, conditions that could have influenced the outcome. The reflex innervation of the striated external sphincter was evaluated by the cough reflex. Normally,
an intra-abdominal pressure increment induces a sacral reflex, which contracts the striated anal and perineal musculature, and thus, prevents rectal leakage. Impaired cough reflex was associated to decreased squeeze pressures, and, as expected, to cough incontinence. However, an impaired cough reflex had no impact on the response to treatment. Neural damage has been associated to poor treatment response, but conceivably, the neuropathy detected by this reflex in our patient population was much less severe than in other reported series. CONCLUSIONS
Anal incontinence is frequently associated to impaired defecatory maneuver, which may play a pathophysiologic role in the process. Biofeedback is an effective therapy for incontinence, but impaired defecatory maneuver and young age are predictive factors of poor outcome. Hence, in patients with anal
incontinence, particularly young patients, a proper evaluation should be performed to detect potential alterations of defecation even if they have only mild or no constipation, because correction of the defecatory dysfunction could potentially improve the outcome of incontinence treatment. |
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