Prediction of sagittal balance in patients with osteoporosis using spinopelvic parameters.

PURPOSE: Little data is available on the relationships between sagittal balance and spinopelvic parameters in osteoporosis. We analyzed sagittal spinopelvic parameters in osteoporotic patients.

METHODS: In this prospective study, the patient and control groups comprised 124 osteoporotic patients and 40 controls. Average age was 72.4 ± 6.8 in the osteoporosis group and 42.7 ± 12.5 in the control group, which was significantly different (P < 0.001). Osteoporotic patients were allocated to two groups by sagittal vertical axis, namely, a sagittal balance group (n = 56) and a sagittal imbalance group (n = 68). All 164 study subjects underwent whole spine lateral radiography, which included hip joints. The radiographic parameters investigated were sacral slope, pelvic tilt, pelvic incidence, thoracic kyphosis, lumbar lordosis, and sagittal vertical axis. Statistical analysis was performed to identify significant differences between the two groups.

RESULTS: Osteoporotic patients and controls were found to be significantly different in terms of sagittal vertical axis, sacral slope, pelvic tilt, lumbar lordosis, and thoracic kyphosis. However, no significant difference was observed between patients and controls in terms of pelvic incidence (P > 0.05). Significant differences were found between the balance and imbalance groups in terms of age, lumbar spine bone mineral density (LSBMD), femoral neck BMD (FNBMD), visual analogue scale (VAS) score, sacral slope, and pelvic incidence. Correlation analysis revealed significant relationships between sagittal parameters and osteoporosis. Stepwise logistic regression analysis revealed that FNBMD and pelvic incidence contributed significantly to sagittal balance.

CONCLUSION: Sagittal spinopelvic parameters were found to be significantly different in patients and normal controls. Significant relationships were found between sagittal spinopelvic parameters in osteoporotic patients. In particular, low FNBMD and high pelvic incidence were significant parameters in determination of sagittal balance in osteoporotic patients.