Does spinopelvic alignment affect the union status in thoracolumbar osteoporotic vertebral compression fracture?

PURPOSE: In the healing of osteoporotic vertebral fracture, global spinal mal-alignment might increase the load sharing at the fracture site and deteriorate the fracture healing. This study aimed to evaluate the effect of spinopelvic alignment on the union status of thoracolumbar osteoporosis-related vertebral compression fracture (OVCF).

METHODS: Consecutive 48 patients with a single-level thoracolumbar fresh OVCF were treated non-operatively. Union was judged by three independent observers at 6 months, and patients were divided into union group and non-union group. Spinopelvic alignment was measured using upright whole spine radiograph before treatment as follows: pelvic incidence (PI), pelvic tilt (PT), lumbar lordosis (LL), thoracic kyphosis (TK), sagittal vertical axis (SVA), and DSVA, defined as the distance from a plumb line dropped from the center of the C7 body to the center of fractured vertebral body.

RESULT: Global spinal alignment was different in union group and non-union group: SVA (4.7 ± 0.7 cm in union group vs. 8.9 ± 1.3 cm in non-union group, P = 0.007), DSVA (4.2 ± 0.6 cm in union group vs. 9.5 ± 1.0 cm in non-union group, P < 0.001), and PI-LL (18.9° ± 2.2° in union group vs. 30.3° ± 3.9° in non-union group, P = 0.014). Over 5 cm of DSVA [P = 0.022, adjusted odds 7.9 (95 % CI 1.3-77.0)] and/or over 30° of PI-LL [P = 0.026, adjusted odds 6.6 (95 % CI 1.5-44.2)] showed the significant risk factors for non-union using multivariate logistic regression analysis in the other background status.

CONCLUSIONS: Global spinal mal-alignment, showing over 5 cm of DSVA and/or over 30° of PI-LL, affected the union status of OVCF.