The mid-term and long-term efficacy of cement augmentation of pedicle screws in the treatment of thoracolumbar osteoporotic vertebral compression fractures complicated with spinal kyphosis deformity

English Keywords:Spine  Osteoporosis  Kyphosis deformity  Polymethyl methacrylate  Pedicle screw

English Abstract:

  【Abstract】 Objectives: To evaluate the safety and mid-term clinical efficacy of cement augmentation of pedicle screws in the treatment of thoracolumbar osteoporotic vertebral compression fractures complicated with spinal kyphosis deformity. Methods: A retrospective study was conducted to analyze the clinical data of elderly patients with osteoporotic vertebral compression fractures complicated with spinal kyphosis deformity admitted and treated from January of 2017 to October of 2020. According to whether pedicle augmentation using bone cement was used, the patients were divided into a cement-augmented group(22 cases, cement-augmented pedicle screws) and a control group(23 cases, pedicle screws without cement augmentation). In the reinforced group, there were 9 males and 13 females; age ranged from 70 to 91 years, with a mean of 78.68±7.12 years; disease duration ranged from 1.1 to 3.8 years, with a mean of 2.39±0.71 years. In the control group, there were 10 males and 13 females; age ranged from 70 to 89 years, with a mean of 77.73±5.83 years, and disease duration ranged from 0.8 to 3.3 years, with a mean of 2.38±0.67 years. The follow-up period was 36-69 months. The incidence of pedicle screw loosening, correction rate of kyphosis, and improvement rate of visual analogue scale(VAS) and Oswestry disability index(ODI) at final follow-up were compared between the two groups. Results: In the cement-augmented group, 1-2 segments of surgical decompression were performed, 6-9 segments were fixed and fused, and 14 cases underwent SPO and 8 cases underwent PSO. The operational time was 221±32mins, and the volume of blood loss was 939±113mL. In the control group, 1-3 segments of surgical decompression were performed, 6-8 segments were fixed and fused, and 16 cases underwent SPO and 7 cases underwent PSO. The operative time was 209±36mins, and the volume of blood loss was 979±111mL. One case in the cement-augmented group and two cases in the control group complicated with cerebrospinal fluid leakage, which were treated with intraoperative repair of the dura mater, tight suturing of the incision, and postoperative Trendelenburg′s position. There was no statistical difference in the comparison of decompression segments(t=1.785, P=0.081), fusion segments(t=0.922, P=0.362), operative time(t=1.162, P=0.252), bleeding(t=1.193, P=0.239), and CSF leak complications(χ2=0.311, P=0.577) between the two groups. There were no complications of incision infection or leakage of bone cement into the spinal canal causing neurological symptoms. At final follow-up, the screw loosening rate was 0% in the cement-augmented group(0/268) and 18.6% in the control group(45/242). The difference in screw loosening rate between the two groups was statistically significant(χ2=54.657, P=0.000). The correction rate of kyphosis deformity was (73.27±9.78)% in the cement-augmented group and (55.96±11.31)% in the control group. There was a significant difference in the correction rate of kyphosis between the two groups(t=5.480, P=0.000). The improvement rate of VAS in the cement-augmented group was (67.94±14.72)%, while in the control group was (74.29±13.18)%. There was no significant difference in the improvement rate of VAS between the two groups (t=1.526, P=0.134). The improvement rate of ODI in the cement-augmented group was (82.01±3.11)%, while in the control group it was (81.96±3.58)%, there was no significant difference in the improvement rate of ODI between the two groups(t=0.41, P=0.968). Conclusions: The application of cement augmentation of pedicle screws in decompression, osteotomy, and long segment fixation fusion for the treatment of thoracolumbar osteoporotic vertebral compression fractures with spinal kyphosis deformity can effectively reduce the loosening rate of pedicle screws and improve the correction rate, resulting in satisfactory clinical outcomes.