The study of T1 pelvic angle and spino-pelvic sagittal balance in thoracolumbar osteoporotic vertebral compression fractures

Objective To investigate the value of T1 pelvic angle (TPA) in the evalution of spino-pelvic sagittal balance through studying thoracolumbar osteoporotic vertebral compression fractures (OVCFs). Methods This was an analysis of 120 cases with thoracolumbar OVCFs, Sagittal parameters of sagittal vertical axis (SVA), T1 pelvic angle (TPA), thoracic kyphosis (TK), thoraco-lumbar kyphosis (TLK), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), the Oswestry disability index (ODI) were measured. The cases were divided into balance group and imbalance group according to the judgment standard of the spinal sagittal balance. The multiple-level vertebral fractures were analyzed in each group. The sagittal parameters of the two groups were analyzed. Results (1) The multiple-level vertebral fractures were found in 67.92% of the imbalance group and 37.13%of the balance group. (2) No difference in PI was found among the two groups (P=0.325), TLK, SVA, TPA, PT, ODI in the imbalance group were bigger than those in the balance group, however, LL, SS was smaller (P=0.000). (3) In the imbalance group, TPA was correlated with SVA, LL, PI, PT, SS, ODI (P=0.000), In the balance group, SVA was correlated with TPA, TK, TLK, LL, PT, ODI, TPA was correlated with TK, TLK, LL, PI, PT, SS, ODI, the balance group tend to present sagittal compensation, meanwhile the imbalance group demonstrated sagittal decompensation with anterior-shifted SVA. Conclusion TPA can both represent the sagittal balance of spine and pelvis. Key words: T1 pelvic angle; Osteoporosis; Vertebral compression fracture; Sagittal balance