Effects of Age and Sex on Anorectal Manometry

Abstract

Purpose: This study was performed to evaluate the effects of age and sex on anorectal manometry. Methods: Seventy-four consecutive patients who underwent surgery for sigmoid colon cancer and who had neither anal disorders nor colonic obstruction were included in this study. There were 45 men and 29 women, and the mean age was 58.6. Pressure measurements used both the rapid and the station pull-through (RPT and SPT) methods, and volume measurements used a balloon-tipped catheter. Three pressure indices (vector volume, maximal pressure, and mean pressure), three sphincter length indices (sphincter length, high pressure zone [HPZ] length, and maximal pressure position), and three volume indices (minimal sensory volume, maximal tolerance volume, and rectoanal inhibitory reflex) were analyzed. Results: Squeezing pressures were higher in men than in women, especially in the RPT method, while resting pressures were not different. Sphincter length and HPZ length were not different between the sexes, but the maximal pressure position was farther from the anal verge in men. Rectal volume indices were not different between the sexes. The resting and squeezing pressures decreased linearly with aging in men, but not in women. The differences in squeezing pressures between men and women were evident in their forties and fifties, but decreased gradually with aging, with no differences being observed in their seventies. With aging, the minimal sensory volume increased in women, and the maximal tolerance volume increased in men. Conclusion: Anal canal pressures and volume indices are influenced by sex, age, and measurement method. Therefore, sex, age, and measurement method must be considered in the evaluation and application of anorectal manometry.