Abstract: BACKGROUND: The high prevalence of osteoporotic vertebral compression fractures leads to a significant socioeconomic and medical burden, and there are controversies about the optimal timing and treatment methods. Percutaneous balloon kyphoplasty can reduce complications, relieve pain, and enhance structural integrity of the vertebral body. 
OBJECTIVE: To investigate the influence of spinal-pelvic sagittal balance on the therapeutic effects of percutaneous balloon kyphoplasty on osteoporotic vertebral compression fractures.
METHODS: The medical records of 74 patients admitted to Hefei First People's Hospital from August 2018 to January 2020 for percutaneous balloon kyphoplasty were retrospectively analyzed, and the included patients were equally divided into the good outcome and poor outcome groups (n=37 per group) according to the postoperative recovery. The visual analog scale scores, Japanese Orthopaedic Association scores, and imaging data of the two groups were compared at baseline and during the postoperative period. 
RESULTS AND CONCLUSION: (1) Cement leakage occurred in three patients in the poor outcome group and four patients in the good outcome group postoperatively, respectively. (2) Visual analog scores in both groups at 1 month postoperatively were similar to baseline (P > 0.05), while the scores were improved significantly at 12 months postoperatively, with the good outcome group significantly better than the poor outcome group (P < 0.05). (3) There was no significant difference in the loss rate of injured vertebral height, Cobb angle, angle of pelvic incidence, pelvic tilt, sacral slope, angle of lumbar anterior convexity, sagittal deviation and thoracic lordosis angle between the both groups (P > 0.05) at baseline, while the loss rate of injured vertebral height, Cobb angle, and sagittal deviation in both groups were significantly improved at 1 month postoperatively (P < 0.05). The rate of height loss of the injured spine, Cobb angle, sagittal deviation, thoracic lordosis angle, pelvic tilt, sacral slope were significantly increased in the poor outcome group compared with the good outcome group (P < 0.05), while the angle of pelvic incidence and angle of lumbar anterior convexity were significantly decreased in the poor outcome group compared with the good outcome group at 12 months postoperatively (P < 0.05). (4) Pearson correlation analysis revealed that Japanese Orthopaedic Association scores were negatively correlated with sagittal deviation, thoracic lordosis angle, pelvic tilt, sacral slope, angle of pelvic incidence (P < 0.05), while were positively correlated with the angle of lumbar anterior convexity (P < 0.05). In addition, the visual analog scale scores were positively correlated with sagittal deviation, thoracic lordosis angle, sacral slope, and angle of pelvic incidence (P < 0.05), while were negatively correlated with the angle of lumbar anterior convexity and pelvic tilt (P < 0.05). (5) These results suggest that percutaneous balloon kyphoplasty can correct deformity, stabilize fracture, and relieve pain, thereby benefiting most of the patients with osteoporotic vertebral compression fractures. Moreover, spine-pelvic sagittal plane balance can affect the clinical efficacy.

Key words: vertebral compression fracture, osteoporosis, percutaneous balloon kyphoplasty, spine-pelvis sagittal plane, clinical efficacy