Colorectal physiological tests: use or abuse of technology?

OBJECTIVE: To assess the value of colorectal physiological tests in patients with functional disorders of defecation.
DESIGN: Prospective study.
SETTING: Academic hospital.
SUBJECTS: 308 consecutive patients.
INTERVENTIONS: Routine history and physical examination, followed by colonic transit study, and manometry, cinedefecography, electromyography of the anal sphincter, and assessment of terminal motor latency of the pudendal nerve. MAIN OUTCOME MEASURES: Number of diagnoses made after physiological tests compared with routine history and examination alone.
RESULTS: Definitive diagnoses were made after history and physical examination alone in 15/180 (8%) with constipation, 9/80 (11%) with incontinence, and 11/48 (23%) with intractable rectal pain. The figures after physiological tests were 135/180 (75%), 53/80 (66%), and 20/48 (42%), respectively. Among the diagnoses made by physiological testing alone were: in patients with constipation, paradoxical puborectalis contraction (n = 59), colonic inertia (n = 31), rectocele (n = 19), and intussusception (n = 18); in those with incontinence, loss of muscle fiber (n = 21), neuropathy (n = 10), and both (n = 15); and in those with rectal pain, neuropathy (n = 6) and paradoxical puborectalis contraction (n = 3). The numbers of patients that remained undiagnosed in the three groups were 45 (25%), 27 (34%), and 28 (58%), respectively. Treatable conditions were diagnosed by physiological testing in 120/180 patients with constipation (67%) and 44 patients with incontinence (55%). Only 9 patients with rectal pain had treatable causes identified by physiologic testing.
CONCLUSION: The value of colorectal physiological tests is greatest in patients who present with constipation or incontinence; they are of little value in those with chronic intractable rectal pain.