Characteristics and treatment of dynamic sagittal imbalance in adult spinal deformity.

OBJECTIVE To raise the diagnostic criteria, classification and treatment strategy of dynamic sagittal imbalance (DSI). METHODS One hundred thirty-three adult spinal deformity (ASD) patients with stooping and back pain after walking were retrospectively analyzed. Based on the radiographic parameters and Oswestry Disability Index (ODI) scores, the diagnostic criteria of DSI were raised. DSI patients received nonoperative treatment and (or) surgery. Radiographic parameters and health-related quality of life (HRQOL) outcomes would be measured and compared between prewalk and postwalk and among each subgroup. RESULTS One hundred thirty-three ASD patients with stooping and back pain after walking were enrolled in our study. The quantitative diagnostic criteria was prewalk SVA   0.05). Patients who received the operative treatment showed prominent improvement in ΔSVA and clinical outcomes (P < 0.001). CONCLUSION Our study proposed a quantitative diagnostic criteria and novel classification of DSI. Nonoperative treatment is effective for most DSI patients with ΔSVA < 100 mm, while the majority of DSI patients with ΔSVA ≥ 100 mm need operative intervention.