ABSTRACT
OBJECTIVES: We have analyzed relationship between pedicle screw loosening and bone mineral densitiy (BMD) after spinal arthrodesis with pedicle screw. MATERIALS AND METHODS: We have chosen 31 cases that had screw loosening radiologically on the follow up X-ray among the patients who underwent spinal arthrodesis with pedicle screws, and compared Saville's index that was measured by lateral view of preoperative X-ray with Dual energy X-ray absortiometry (DEXA) score.
Subject(s)
Humans , Arthrodesis , Bone Density , Follow-Up Studies , Osteoporosis , Risk Factors , SpineABSTRACT
We report a case of pedicle screw loosening treated by modified transpedicular screw augmentation technique using polymethylmethacrylate (PMMA), which used the anchoring effect of hardened PMMA. A 56-year-old man who had an L3/4/5 fusion operation 3 years ago complained of continuous low back pain after this operation. The computerized tomography showed a radiolucent halo around the pedicle screw at L5. We augmented the L5 pedicle screw with modified pedicle screw augmentation technique using PMMA and performed an L3/4/5 pedicle screw fixation without hook or operation field extension. This modified technique is a kind of transpedicular stiffness augmentation using PMMA for the dead space around the loosed screw. After filling the dead space with 1-2 cc of PMMA, we inserted a small screw. Once the PMMA hardened, we removed the small screw and inserted a thicker screw along the existing screw threading to improve the pedicle screws' pullout strength. At 10 months' follow-up, x-ray showed strong fusion of L3/4/5. The visual analogue scale (VAS) of his back pain was improved from 9 to 5. This modified transpedicular screw augmentation with PMMA using anchoring effect is a simple and effective surgical technique for pedicle screw loosening. However, clinical analyses of long-term follow-up and biomechanical studies are needed.