Screw loosening and loss of correction are main complications in patients with osteoporosis receiving pedicle screw implantation. Therefore, osteoporosis is considered as a relative contraindication for pedicle screws.OBJECTIVE:
To study the clinical results of methods for improving stability of pedicle screw in patients with osteoporosis.METHODS:
Thirty-four patients with osteoporosis were treated with pedicle screw internal fixation, and the methods of improving stability of pedicle screw were applied during the operation. There were 14 cases of fractures (fracture group) and 20 cases of osteopathy. Spinal posterolateral or intervertebral body graft fusion was performed in the 20 cases of osteopathy and five cases of fractures (fusion group). According to Jikei grading scale for osteoporosis, eight cases were in early stage, 11 cases I stage, eight cases II stage and seven cases III stage. For 19 cases inearly stage and I stage osteoporosis, longer and large size of pedicle screws were used, combined with rod system with ankylosing connection between screws and connecting rods using two cross-link devices, placement of pedicle screw with large angles in the horizontal and the sagittal planes were applied to improve the relative stability of screw. For 15 cases of II stage and III stage osteoporosis, bone cement was used to fill the screw path to improve the absolute stability of screw.RESULTS AND CONCLUSION:
There was no breakage of screw during the follow-up with the mean period of 14 months (ranged 9-26 months), only two cases in fracture group with Jikei I stage osteoporosis had screw loosening at 5 to 6 months after fixation, as well as partial loss of correction of reduction, but no other adverse effects. The loss of correction of reduction in the fracture group was 5% in average, and the fusion rate was 100% in the fusion group. Different methods of improving the stability of pedicle screw applied in patients with osteoporosis according to different situations may reduce the occurrence of complications, such as screw loosening and loss of correction.