Comparison of bone cement augmented with traditional pedicle screw in the treatment of degenerative lumbar disease

Abstract

Objective To compare post-operative clinical outcomes between bone cement augmented pedicle screw and traditional pedicle screw in treatment of degenerative lumbar disease. Methods Data of 40 cases with lumbar degenerative disease who had surgery from May 2013 to May 2015 were retrospectively analyzed. They were divided into two groups according to whether the bone cement was injected in the vertebral body with pedicle screw: conventional group and augmented group. There were 5 males and 15 females in conventional group with an average age of 73.2, among them there were 12 cases of lumbar disc prolapse and 8 cases of lumbar spinal stenosis. There were 6 males and 14 females with an average age of 73.7, among them there were 12 cases of lumbar disc prolapse and 8 cases of lumbar spinal stenosis. The screws were inserted into L3, L4, L5, and S1 with a total of 170 vertebral bodies. The Oswestry Disability Iindex (ODI), intervertebral distance of the upper adjacent segments, deformation index of the upper adjacent vertebral body, Cobb angle, concave angle of the fixed lumbar vertebrae superior end-plate and the upper adjacent vertebral body inferior end-plate were measured pre-operation, 30 d postoperatively and at final follow-up. Results 40 patients were followed-up for 3-24 months (average 12.2 months). The ODI of traditional group and bone cement augmented group respectively was 13.0%±4.9% and 11.0%±8.0%, and there was no significant difference between two groups. The change of Cobb angle of fixed lumbar vertebrae at the final follow-up and 30 days postoperatively was 5.53°±1.64° and 2.15°±0.97°. The concave angle of upper end-plate was increased in bone cement augmented group at 30 days after operation compared with that in conventional group; the lower end-plate concave angle of adjacent centrum, the rectangular index and the adjacent intervertebral space of conventional pedicle screw with bone cement group was all decreased in the final follow-up, and the change of the first two indicators was significantly bigger than those in the conventional pedicle screw group. Conclusion Both groups can effectively treat the degenerative lumbar disease, but bone cement augmented pedicle screw can maintain the stability of the spine of aged patients better. Key words: Osteoporosis; Bone screws; Lumbar vertebrae; Intervertebral disc degeneration