CAN DIGITAL EXAMINATION SUBSTITUTE ANORECTAL MANOMETRY FOR THE EVALUATION OF ANAL-CANAL PRESSURES

INTRODUCTION: anorectal manometry provides objective information on th e sphincter function of the anal canal. However, in many centers sphin cter function is evaluated by digital examination, due to the unavaila bility of manometry. OBJECTIVE: a study is made to correlate the sensi tivity and specificity of a quantitative digital examination in the an alysis of sphincter tone with the pressures recorded by manometry, and to examine the capacity of both techniques to discriminate continent subjects and incontinent patients. PATIENTS AND METHODS: a total of 19 1 patients were divided into three groups: control (C), obstructive de fecation (OD) and fecal incontinence (FI). Subjective quantitative dig ital evaluation of anal tone was performed on a scale of 0 to 5 points at rest, and 0 to 10 points at squeeze. A correlation analysis was pe rformed, and the sensitivity and specificity of each fecal incontinenc e diagnostic test was determined. RESULTS: digital examination found r ectal tone to be diminished in elderly patients. A significant correla tion was established between the digital and manometric tone readings, both at rest and at squeeze. Both techniques showed a low anal sphinc ter pressure in the Fl group versus the C and OD groups. Differences i n tone were recorded between the C and OD groups with manometry, but n ot with digital examination. The latter was in turn found to be more s ensitive but less specific than manometry in differentiating between f ecal continence and incontinence. CONCLUSIONS: although digital examin ation does not substitute anorectal manometry, a good correlation exis ts between the two techniques. In this sense, digital examination may afford an approximate clinical evaluation of some fecal continence mec hanisms in those centers where manometry is not available.