Shape differences in the bony pelvis of women with and without pelvic floor disorders

Abstract

Pelvic floor disorders (PFDs) include a suite of urinary and gastrointestinal tract problems that have a negative impact a woman's quality of life and effect up to one‐third of women. Earlier studies focused on width of the pelvis as a risk factor for PFDs. This is the first study to address the association of complex 3D pelvic shape with PFDs. We hypothesize that insertion sites of the muscular pelvic diaphragm are displaced further from one another in women with PFDs relative to unaffected controls. This study uses 3D geometric morphometrics to analyze the bony pelvis in a clinical sample of women with (n=6) and without (n=11) PFDs. Landmarks (k=41) were collected on pelvic reconstructions from MR data. Generalized Procrustes Analysis (GPA) and Euclidean Distance Matrix Analysis (EDMA) were used to localize shape differences between the control group and the affected group.GPA analysis identified significant shape differences between the two groups (α<.05); relative to other landmarks, the sacrum and ischial spines move posteriorly, and the iliac blades move medially and superiorly in women with PFDs. EDMA analyses demonstrated that the majority of differences between groups included the posterior displacement of the sacrum and antero‐posterior elongation of the birth canal. These results suggest that the posterior elongation of the pelvic diaphragm may be a better predictor of risk for PFD than pelvic width alone.Grant Funding Source: none