Abstract: BACKGROUND: Percutaneous kyphoplasty was a common surgical procedure for the treatment of osteoporotic vertebral compression fracture. However, there was no research to confirm whether percutaneous kyphoplasty could effectively correct the local kyphoplasty of the spine in patients over 80 years old with osteoporotic vertebral compression fracture. 
OBJECTIVE: To investigate the effect of percutaneous kyphoplasty on local kyphosis in super-aging patients with osteoporotic vertebral compression fracture.   
METHODS: Single-segment osteoporotic vertebral compression fracture patients treated with percutaneous kyphoplasty at the Department of Spinal Surgery, Peking University People's Hospital, from March 2016 to August 2022, were selected as the research cohort, and the follow-up data of patients in hospital and out-patient were collected. According to patients' age, patients were divided into the advanced age group (60-79 years old, n=126) and the super-aged group (≥ 80 years old, n=52). According to gender, body mass index, basic diseases (hypertension, diabetes, and cardiovascular diseases), fracture segments and the presence or absence of preoperative intravertebral cleft, the two groups of patients were matched 1:2 by propensity score matching. The lumbar CT values, injection amount of bone cement, preoperative and postoperative vertebral height, preoperative collapse rate of the vertebral body, preoperative and postoperative Cobb angle, recovery rate of Cobb angle, distance between the bone cement and anterior edge of the vertebral body, sagittal position of cement filling, contact between the bone cement and endplate, distance between the bone cement and vertebral endplates, bone cement distribution score, bone cement leakage, and vertebral refracture were compared between the two groups. 
RESULTS AND CONCLUSION: (1) After matching the propensity score, 115 patients were included, with 71 patients in the advanced age group and 44 patients in the super-aged group. There was no statistically significant difference in baseline data, including gender, body mass index, hypertension ratio, diabetes ratio, cardiovascular disease ratio, fracture section, and preoperative intravertebral cleft, between the two groups (P > 0.05). The postoperative Cobb angle of the super-aged patients was significantly smaller than that of the elderly patients (P < 0.05). There was no significant difference in lumbar CT values, injection amount of bone cement, preoperative and postoperative vertebral height, preoperative collapse rate of the vertebral body, preoperative Cobb angle, recovery rate of Cobb angle, postoperative distance between the bone cement and anterior edge of the vertebral body, sagittal position of cement filling, contact between the bone cement and endplate, distance between the bone cement and vertebral endplates, bone cement distribution score, bone cement leakage, and vertebral refracture ratio between the two groups (P > 0.05). (2) These findings indicate that percutaneous kyphoplasty can effectively correct local kyphosis of the spine in super-aging patients with osteoporotic vertebral compression fractures.

Key words: osteoporotic vertebral compression fracture, percutaneous kyphoplasty, local kyphosis of the spine, Cobb angle, super-aging, propensity score matching, cohort study, engineered bone material