Lumbosacral spine and pelvic inlet changes associated with pelvic organ prolapse.

OBJECTIVE To determine the association between advanced pelvic organ prolapse and changes in lumbar lordosis and/or pelvic inlet orientation. METHODS Lateral lumbosacral spine/pelvic x-rays were taken of women with grade 2 or greater uterovaginal prolapse and women with grade 1 or less prolapse standing in their usual upright posture. The angles of lumbar lordosis and the pelvic inlet were measured by a radiologist who was masked to the pelvic examination findings. RESULTS Twenty women with prolapse were matched with 20 women without significant prolapse. There were no significant differences in the mean (+/- standard deviation [SDI) age (55.3 +/- 9.0 years compared with 53.4 +/- 9.5 years), body mass index (BMI) (28.9 +/- 5.6 compared with 28.4 +/- 5.2), gravidity (5.6 +/- 3.5 compared with 5.0 +/- 2.7), and vaginal parity (4.65 +/- 3.3 compared with 4.5 +/- 2.9) between the prolapse and nonprolapse groups, respectively. All participants were vaginally parous. The mean lumbar lordotic angle in women with pelvic organ prolapse (32.0 degrees +/- 9.8 degrees) was significantly lower than that of controls (42.4 degrees +/- 10.9 degrees) (P < .003). The mean angle of the pelvic inlet in women with pelvic organ prolapse (37.5 degrees +/- 7.0 degrees) was significantly larger than that of controls (29.5 degrees +/- 7.3 degrees) (P < .001). The differences in the mean angles of lumbar lordosis and the pelvic inlet, between the case and control groups, remained significant after multivariable logistic regression was performed. CONCLUSION Women with advanced uterovaginal prolapse have less lumbar lordosis and a pelvic inlet that is oriented less vertically than women without prolapse.