Anal tonometry: a quick method of anal manometry.

Evaluation of anal sphincter tonic activity is important in the proctologic clinic. However, manometric techniques are expensive, complex, and only available in some centers. Because there is often an in-office need for having objective measurements of anal tonic activity, in our clinic we introduced a simple method for measurement of anal pressures. This method is based on the flow of air in an open circuit by using a rubber probe with a side opening at one end. Pressure is assessed by an ordinary manometric gauge for arterial pressure. With this simple instrument, the following parameters are measured: 1) anal resting pressure, 2) squeeze pressure, 3) functional length of the anal canal, and 4) descent of the perineum on staining. After testing the technique in 100 healthy persons, it was applied to 130 patients with several proctologic disorders. Differences in pressures were found between controls and patients with anal fissure (high resting pressures), and patients with anal incontinence (low resting and/or squeeze pressures). A correlation was also found between the descending perineum measured by this method and by defecography. This simple instrument is useful in the office as the first approach to the function of the anal sphincters and the pelvic floor. Nowadays, so-called anal tonometry is part of the proctologic examination in our department, because it is simple, reliable, and takes only a few minutes.