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 [SD]) 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. (Obstet Gynecol 2000;95:332-6. (C) 2000 by The American College of Obstetricians and Gynecologists.).