To investigate the clinical application of anorectal manometry in evaluating the anal function for middle or low rectal cancer patients before anus reservation operation.

The detection system of anorectal dynamics (Laborie anorectal manometry, ARM) was used to record anorectal pressure of 107 patients with middle or low rectal cancer before operation and the clinical data was analyzed by vector pressure software.

The anal canal resting pressure of patients with middle or low rectal cancer was slightly higher, while the minimum perception threshold and initial defecating sensation volume were obviously higher than the healthy controls. There was a significant difference in anal length and anal maximal contraction pressure between male and female patients with middle or low rectal cancer (P<0.05). For anal maximal contraction pressure, there were differences between patients with middle and low rectal cancer (P<0.05). Between younger than and older than sixty years old patients, anal resting pressure and anal maximal contraction pressure had significant differences.

Gender, age and tumor location are the impact factors to anal function of rectal cancer. Anorectal manometry can be used to detect the function of internal and external anal sphincter and to evaluate self-control ability in defecation for middle or low rectal cancer patients.