Constipation affects 4% of adults in the United States (U.S.). An estimated half of constipated patients are unable to relax pelvic floor muscles during defecation, a type of constipation called pelvic floor dyssynergia (PFD). Biofeedback has been recommended for the treatment of constipation because uncontrolled studies over the past 10 years suggest that these treatments are as effective as medical or surgical management and involve no risk. However, placebo-controlled trials are still lacking. The aims of this study are:

• to compare biofeedback to alternative therapies for which patients have a similar expectation of benefit;
• to identify which patients are most likely to benefit; and
• to assess the impact of treatment on quality of life.

This study is a long-term prospective, single-blind study comparing biofeedback for pelvic floor dyssynergia to a skeletal muscle relaxant drug (diazepam 5 mg two hours before attempted defecation) and to placebo medication. Prior to randomization, patients will first receive medical therapy (laxatives and education) for 4 weeks and only those remaining constipated will be randomized. Physiological tests of anal canal pressure during straining to defecate and ability to pass a 50-ml air filled balloon will be tested before and after treatment. Patients will keep a diary throughout baseline and treatment, and they will be reassessed at 3, 6, and 12 months follow-up. Treatment will consist of 6 clinic visits at 2-week intervals. The investigators will develop a detailed treatment manual for this disorder which would permit other investigators to replicate their study.

Inclusion Criteria:

• Males or females ages 16 or above who have symptoms of constipation due to pelvic floor dyssynergia

Exclusion Criteria:

• Pregnancy (because of the possibility of randomization into the diazepam group)
• Prior history of biofeedback treatment for pelvic floor disorders