Posterior pelvic tilt is a risk factor for rectal prolapse: a propensity score matching analysis

Background There is little evidence about possible effects of pelvic anatomical characteristics on proctological complications. The aim of our study was to investigate the potential correlation between sagittal pelvic position and rectal prolapse. Methods A study was conducted on a proctology patients and patients without any specific history of proctological disorders who were divided into two groups according to the presence or the absence of rectal prolapse. In all cases, the pelvic angle was measured with a pelvic goniometer and categorized as posterior (< 10 degrees), neutral (10 degrees-15 degrees), and anterior (> 15 degrees). To minimize effects of potential confounders in the analysis, 3:1 nearest neighbor propensity score matching (PSM) method was implemented using age, sex, and diagnose of rectal disorders as confounding variables. Results Among the 143 screened patients, posterior tilt was more frequent in the 19 patients with rectal prolapse than in those without prolapse (42 vs. 18%; p = 0.027). This result was also confirmed in the post-PSM analysis (42 vs. 14%; p = 0.036) using 35 propensity score (PS)-matched controls compared with the rectal prolapse group. Posterior tilt was associated with an increased risk of prolapse in both the unmatched population (odds ratio = 3.37; p = 0.020) and PS-matched subset (odds ratio = 4.36; p = 0.028). Conclusions A posterior pelvic angle was more frequently associated with the diagnosis of rectal prolapse. In both the entire population and in the PS-matched subset, posterior tilt was a significant risk factor for rectal prolapse. The easy-to-do investigation of the pelvic angle can provide several benefits in terms of rectal prolapse prevention and more precise management of post-surgical prolapse recurrence.