Abstract: BACKGROUND: Vertebroplasty in the treatment of osteoporotic vertebral compression fracture has experienced more than 20 years of clinical practice, but the intraoperative bone cement leakage is still a difficult clinical problem.
OBJECTIVE: To evaluate the efficacy of bone cement interval perfusion in hyperextension position for treatment of senile osteoporotic vertebral compression fractures.  
METHODS: Between May 2015 and December 2020, 120 patients who suffered from osteoporotic vertebral compression fractures were treated with percutaneous kyphoplasty in hyperextension position in the Affiliated Suzhou Hospital of Nanjing Medical University. The patients were at the age of ≥ 80 years. According to the way of bone cement perfusion, they were randomly divided into conventional bone cement injection group (n=60, bone cement mixed one-time injection) and bone cement interval perfusion combined reduction group (n=60, preoperative position reduction + bone cement perfusion at different times). Visual analogue scale score, Oswestry dability index, Cobb angle, anterior edge height of injured vertebra, improvement of lung function, and the occurrence of cement leakage were compared between the two groups 1 week postoperatively and during final follow-up. This study was approved by the Affiliated Suzhou Hospital of Nanjing Medical University (approval No. KL901173). 
RESULTS AND CONCLUSION: (1) Both groups were followed up for more than 12 months after surgery. The bone cement leakage rate in the bone cement interval perfusion combined reduction group was lower than that in the conventional bone cement injection group (3.3%, 15.0%, P < 0.05). (2) The visual analogue scale score and Oswestry dability index of the two groups after surgery were lower than those before operation (P < 0.05), and there was no significant difference between the two groups (P > 0.05). (3) The postoperative Cobb angle of the injured vertebrae and anterior edge height of injured vertebra were significantly improved compared with that before operation. The Cobb angle and anterior edge height of injured vertebra in the bone cement interval perfusion combined reduction group were better than those in the conventional bone cement injection group at 1 week after operation and the last follow-up (P < 0.05). (4) The forced vital capacity and maximum voluntary ventilation of patients in the conventional bone cement injection group were significantly improved after surgery compared with those after surgery (P < 0.05). The postoperative vital capacity, forced vital capacity and maximum voluntary ventilation in the bone cement interval perfusion combined reduction group were significantly improved compared with preoperative data (P < 0.05). Vital capacity, forced vital capacity, and maximum voluntary ventilation in the bone cement interval perfusion combined reduction group 1 week after operation and the last follow-up were higher than those of the conventional bone cement injection group (P < 0.05). (5) The results showed that satisfactory imaging and clinical results can be obtained by the method of bone cement interval perfusion in hyperextension position. This method can significantly reduce the incidence of bone cement leakage and improve lung function. 

Key words: osteoporosis, vertebral compression fracture, senile, percutaneous kyphoplasty, bone cement, hyperextension position, cement leakage