MANOMETRIC MEASUREMENT OF ANAL-CANAL RESTING TONE - COMPARISON OF A RECTOSPHINCTERIC BALLOON PROBE WITH A WATER-PERFUSED CATHETER ASSEMBLY

The purpose of this study was to compare the manometric measurements o f a rectosphincteric balloon probe with a water-perfused catheter asse mbly on anal canal resting tone. Ten normal subjects (9 males, 1 femal e; mean age: 32 years; range 27-46 years) underwent station pull-throu gh (0.5 cm/3 sec) beginning in the rectum with a water-perfused cathet er assembly and a rectosphincteric balloon probe. Both the probe and t he catheter were 5 mm in diameter. Three catheter side ports were perf used at 1 ml/min, and the rectal balloon was inflated with 5 mi of air . Measurements were taken on the same day in a counterbalanced manner. Data were analyzed on a computerized system. Mean (+/- SEM) values wi th the balloon were 82.3 (+/- 8.9) mm Hg and 97.1 (+/- 9.3) mm Hg with the catheter. These values were not significantly different (P = 0.22 ). A significant order effect (P = 0.04) was found where the first mea sure (101.3 +/- 10.2 mm Hg) was higher than the second measure (78.1 /- 6.6 mm Hg), which was controlled for in the experimental design. A rectosphincteric balloon probe can accurately measure the resting tone of the anal canal compared to a water-perfused catheter assembly. Cau tion should be used when measuring anal canal resting tone early in an anorectal manometry assessment.