Comparison of bony dimensions at the level of the pelvic floor in women with and without pelvic organ prolapse

OBJECTIVE: We sought to compare bony pelvis dimensions at the level of pelvic support in women with and without pelvic organ prolapse (POP). STUDY DESIGN: Pelvic floor dimensions of 42 white women with POP > 1 cm beyond the hymen were compared with 42 age- and parity-matched women with normal support. Bony landmarks relevant to connective tissue and levator attachments were identified on magnetic resonance imaging. Dimensions were independently measured by 2 examiners and averaged for each subject. RESULTS: Measurements (in centimeters) for patients and control subjects were as follows: interspinous diameter, 11.2 +/- 0.8 versus 11.1 +/- 0.7, P = .19; anterior-posterior outlet diameter, 11.7 +/- 0.7 versus 11.7 +/- 0.8, P = .71; pubic symphysis to ischial spine left, 9.5 +/- 0.5 versus 9.5 +/- 0.4, P = .91; pubic symphysis to ischial spine right, 9.5 +/- 0.4 versus 9.5 +/- 0.5, P = .81; sacrococcygeal junction to ischial spine left, 7.0 +/- 0.6 versus 7.0 +/- 0.5, P = .54; and sacrococcygeal junction to ischial spine right, 7.0 +/- 0.6 versus 6.9 +/- 0.4, P = .32. CONCLUSION: Bony pelvis dimensions are similar at the level of the muscular pelvic floor in white women with and without POP.