A fast classification system for adult spinal deformity with sagittal imbalance based on spinal sagittal parameters.

OBJECTIVES

To investigate a new classification based on driving factors for adult spinal deformity with sagittal imbalance.

METHODS

We included adult spinal deformity with sagittal imbalance patients who had corrective surgery from June 2019 to July 2022. The patient's lumbar MRI and whole spine X-rays were evaluated. Oswestry Disability Index (ODI) and a visual analog scale (VAS) were used to evaluate clinical outcomes. According to sagittal parameters of sagittal imbalance, patients were divided into Type A (pelvic incidence - lumbar lordosis of > 10°), Type B (thoracic lumbar kyphosis < - 20° and/or thoracic kyphosis<-60°), Type C (Type A combined Type B), and Type D (after walking for 10 min, the sagittal vertical axis increased by more than 5 cm).

RESULTS

There were 116 patients: 67 Type A, 12 Type B, 17 Type C, and 20 Type D. The grade of intervertebral disc degeneration in Type A patients is higher than that in the other three groups (p < 0.001). Type B patients had more wedge-shaped vertebrae than that of Type A and Type D patients (p < 0.001). Preoperative thoracic kyphosis in Type B patients is smaller than the other three groups (p < 0.001). Type D patients are mainly characterized by paraspinal muscle atrophy, with paraspinal muscle atrophy and fat infiltration. Patients with sagittal imbalance had surgical segments based on classification. There was no significant difference in postoperative spinal sagittal parameters among the four groups (p > 0.05). ODI and VAS scores improved in all groups (p < 0.001).

CONCLUSIONS

Different types of sagittal imbalanced patients have different causes and compensatory behaviors, requiring different surgical strategies.