Characteristics and correlation analysis of spino-pelvic sagittal parameters in elderly patients with lumbar degenerative disease

BACKGROUND: Retrospective analysis of the characteristics and correlation of spino-pelvic sagittal parameters in elderly patients with lumbar degenerative disease. METHODS: Eighty-seven patients with lumbar degenerative disease, with an average age of 75.4 years old, were enrolled in the observation group. They were all from the orthopedics department of Beijing Hospital and got enrolled in this study from August 2015 to October 2017. Another 80 volunteers, with an average age of 74.5 years old, were enrolled in the control group. Standing lateral radiographs of the full-length spine were taken for all subjects. The following spino-pelvic sagittal parameters were measured: sagittal vertical axis (SVA), thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), and pelvic tilt (PT). Statistical analysis was performed to compare the differences of the parameters between groups, and the correlation analysis was also performed. RESULTS: SVA, PI, and PT of the observation group were significantly higher than those of the control group (p < 0.01), while LL and SS were significantly lower in the observation group (p < 0.01). No significant differences were found in TK between the two groups. The correlation analyses showed that PI was significantly correlated with SS and PT in both the observation group (p < 0.01) and the control group (p < 0.01), so as the SVA-PI (p < 0.05) and SVA-PT (p < 0.01). SS-PT was also significantly correlated in the observation group (p < 0.01) and in the control group (p < 0.05). LL was significantly correlated with all the other parameters in the observation and control groups, including SVA (p < 0.01; p < 0.01), TK (p < 0.01; p < 0.01), PI (p < 0.01; p < 0.01), SS (p < 0.01; p < 0.01), and PT (p < 0.01; p < 0.01). SVA-SS (p < 0.05), TK-PI (p < 0.05), and TK-SS (p < 0.01) were significantly correlated in the control group but not in the observation group. CONCLUSION: Reduced coordination of the spine and pelvis in elderly patients with lumbar degenerative disease was observed. Many of the cases were in the state of sagittal imbalance, with the trunk center of gravity moving forward, the integral sagittal alignment becoming straight, and the pelvic posterior tilt increasing. Pelvic parameters were significantly correlated with each other, which may affect the sagittal curve of the spine. LL was a core parameter that significantly correlated with various sagittal parameters.