Assessment of anal sphincter function by Sengstaken-Blakemore tube anal manometry

Anal manometry is a useful tool for testing the effectiveness of surgical treatment. However, most techniques for anal pressure measurement are not easily available because of high cost. The aim of the present study was to introduce an easy and reproducible method for measuring anal pressures in testing the effectiveness of surgical procedures.

We used a Sengstaken-Blakemore tube connected to a mercury manometer. After calibration of the system by inflating the distal (gastric) balloon and filling connection lines to the mercury manometer with 0.9% NaCl solution, resting and squeezing anal pressures were measured. The system was used on 50 human subjects (35 with anal fissure and 15 normal volunteers). Left lateral internal sphincterotomy had been performed in the anal fissure cases. Anal pressures were measured preoperatively and on postoperative days (POD) 2 and 20.

Preoperative resting anal pressures in the group with anal fissure (83.4 +/- 1 mmHg) were significantly higher than those in the group of normal individuals (52 +/- 1.2 mmHg; p = 0.001). Resting anal pressures after the sphincterotomy (29 +/- 1 mmHg) were found to be significantly lower on POD 2, and resting anal pressure measurements (47 +/- 1 mmHg) on POD 20 were lower than the corresponding preoperative values. These values are closer to those of normal volunteers (p = 0.016).

Anal manometry can be performed with this easily constructible and inexpensive system. This reproducible method can be used in the assessment of the results of surgical treatment in patients with anal and perianal diseases.