Prospective Assessment of the Clinical Value of Anorectal Investigations

Background/aim: Anorectal physiological testing and imaging have become part of routine colorectal and gastro-enterological practice, but their clinical value is controversial. We prospectively evaluated the new diagnostic information, impact on management and prognostic information provided by anorectal testing.

Methods: One hundred consecutive patients referred for testing were studied. The referring doctor's diagnosis, reason for referral, planned management and expectation of the value of investigations were recorded. Incontinent patients underwent anorectal physiological testing and endo-anal ultrasound. Patients with constipation underwent anorectal physiological testing and a study of whole-gut transit time to distinguish between slow and normal transit. Constipated patients over age 45, or those younger patients who digitated to assist defaecation, also underwent evacuation proctography to identify large rectoceles.

Results: Fifty-one patients had faecal incontinence. Of 12 patients with suspected anterior external anal sphincter obstetric damage, all of whom were planned for surgical repair, 3 were unsuitable for repair, 3 had a normal sphincter, 2 had a weak but structurally intact sphincter, and 1 had internal anal sphincter damage only. Of 6 patients with failed anterior repair, 3 had a defect suitable for repeat repair, 2 had intact repairs and good function, and 1 had extensive damage requiring reconstructive surgery. The tests also influenced management for incontinent patients after haemorrhoidectomy surgery (n = 5), after fistula surgery (n = 5), with congenital abnormalities (n = 3), after cerebrovascular accident (n = 1) and those with no presumptive diagnosis (n = 15). Of the 20 patients referred with constipation, demonstration of a recto-anal reflex in 1 patient with a megarectum excluded the need for full-thickness biopsy. A further patient with altered electrosensation went on to have a neurological lesion defined. Definition of slow transit in some patients did not immediately affect management. New information or a change in management was provided in patients referred for pre-operative assessment (n = 13). Information was gained in only 1 of 7 patients with solitary rectal ulcer and in none of the 8 patients with anal pain.

Conclusion: Anorectal assessment provides important diagnostic and prognostic information and directly alters management in patients with benign anorectal disorders.