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119 Biofeedback Treatment of Constipation [2003년 9월 DCR] 2011-11-17 3073
 
A Critical Review

Steve Heymen, M.S., Kenneth R. Jones, Ph.D., Yolanda Scarlett, M.D.,William E. Whitehead, Ph.D.

From the Center for Functional Gastrointestinal and Motility Disorders, Department of Medicine, The University of North Carolina, Chapel Hill, North Carolina
 
PURPOSE: This review was designed to 1) critically examine the research design used in investigations of biofeedback for pelvic floor dyssynergia, 2) compare the various biofeedback treatment protocols for pelvic floor dyssynergia-type constipation used in this research, 3) identify factors that
influence treatment outcome, and 4) identify goals for future biofeedback research for pelvic floor dyssynergia.
METHODS: A comprehensive review of both the pediatric and adult research from 1970 to 2002 on “biofeedback for constipation” was conducted using a Medline search in all languages. Only prospective studies including five or more subjects that described the treatment protocol were included. In addition, a meta-analysis of these studies was performed to compare the outcome of different biofeedback protocols for treating constipation.
RESULTS: Thirtyeight studies were reviewed, and sample size, treatment protocol, outcome rates, number of sessions, and etiology are shown in a table. Ten studies using a parallel treatment design were reviewed in detail, including seven that randomized subjects to treatment groups. A meta-analysis
(weighted by subjects) was performed to compare the results of two treatment protocols prevalent in the literature. The mean success rate of studies using pressure biofeedback (78 percent) was superior (P = 0.018) to the mean success rate for studies using electromyography biofeedback (70 percent). However, the mean success rates comparing studies using intra-anal electromyography sensors to studies using perianal electromyography sensors were 69 and 72 percent, respectively, indicating no advantages for
one type of electromyography protocol over the other (P = 0.428). In addition to the varied protocols and instrumentation used, there also are inconsistencies in the literature regarding the severity and etiology of symptoms, patient selection criteria, and the definition of a successful outcome. Finally, no anatomic, physiologic, or demographic variables were identified that would assist in predicting successful outcome. Having significant psychological symptoms was identified as a factor that may influence treatment outcome, but this requires further study.
CONCLUSION: Although most studies report positive results using biofeedback to treat constipation, quality research is lacking. Specific recommendations are made for future investigations to 1) improve experimental design, 2) clearly define outcome measures, 3) identify the etiology and severity of symptoms, 4) determine which treatment protocol and which component of treatment is most effective for different types of subjects, 5) systematically explore the role of psychopathology in this population, 6) use an adequate sample size that allows for meaningful analysis, and 7) include long-term follow-up data.
 
Constipation is a common disorder, occurring in an estimated 4 percent of United States adults, with pelvic floor dyssynergia-type constipation (PFD) making up an estimated 25 to 50 percent of this group. Preston and Lennard-Jones first described the association of PFD with constipation, and subsequent investigators have confirmed their observation using a variety of synonymous terms, such as anismus, spastic pelvic floor syndrome, outlet obstruction, and paradoxical puborectalis contractions.
 
During the act of defecation, the puborectalis sling muscle and the external anal sphincter should relax to permit defecation. This can be demonstrated by recording electromyographic activity or anal canal pressure from pelvic floor muscles during attempts to defecate. However, some chronically constipated patients inappropriately contract or fail to relax the external anal sphincter and puborectalis muscles. This uncoordinated effort obstructs defecation.
 
Some studies suggest that the finding of PFD varies from one occasion of testing to another and is less
likely to be seen at home when ambulatory monitors are used to record the response to straining. PFD also is observed in some asymptomatic controls and fecalincontinent patients, leading some investigators to question whether this is a distinct abnormality causing constipation. However, most clinicians and researchers believe that although current diagnostic criteria can lead to a false-positive diagnosis, a subgroup of patients exists whose symptoms of chronic constipation and/or fecal impaction occur as a result of inability to relax the pelvic floor when straining to defecate.
 
Although constipation is not life threatening, it does have an adverse effect on quality of life and is associated with significant morbidity and costs (e.g., cost of care and work absenteeism). In a United States Householder Survey of functional gastrointestinal disorders, 9 percent of constipation subjects reported being too sick to go to work. Patients with symptoms of difficult defecation showed significant impairments on the Health Survey Questionnaire (SF-36) scales for “bodily pain,” “role physical” (limitations in ability to work or perform usual physical activities), and “general health,” even when the possible mediating effects of neuroticism are statistically controlled. The estimated cost of laxative use alone is more than 4 million dollars annually in the United States. Furthermore, when traditional treatments are unsuccessful, symptoms often worsen over time.
 
When patients do not respond to conservative interventions such as dietary recommendations, bowel
scheduling, and medications, biofeedback is frequently used to treat PFD-type constipation. Because
uncontrolled trials suggest that biofeedback is associated with outcomes as good as medical management or surgery, and because it has a low incidence of adverse effects, biofeedback often is recommended as the first-line treatment for patients with PFD.
 
Biofeedback studies for treating PFD have been reviewed by others. Those reviews suggest that
approximately two-thirds of adult patients with pelvic floor dyssynergia benefit from biofeedback training.
However, despite more than 20 years of positive results that are reported in the literature, the lack of
adequately controlled trials has limited the widespread use of what seems to be a promising treatment.
 
This review was designed to 1) critically examine the research designs used in investigations of biofeedback for PFD, 2) compare the various biofeedback treatment protocols for PFD-type constipation used in this research, 3) identify factors that influence treatment outcome, and 4) identify goals for future research of biofeedback for PFD.