科研之友
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摘要
Clinical practices in spinal surgery have shown that pedicle screw fixation augmented by polymethyl methacrylate (PMMA) bone cement has improved outcomes for osteoporotic patients, Here, a biodegradable calcium phosphate-based nanocomposite (CPN) exhibiting better anti-pullout ability but similar fluidity and dispersing ability compared to clinically-used polymethyl methacrylate (PMMA) was developed. The present study showed that the axial pullout strength of cement-augmented pedicle screws was increased as the liquid/solid ratio (L/S) of CPN decreased. Mechanical evaluation using ASTM-standard Sawbones showed that the axial pullout force of CPN could reach approximate to 720N at the L/S ratio of 0.4 mL/g, while PMMA cannot be injected through the screw. In vitro evaluation in decalcified sheep vertebral models showed that the axial pullout forces of CPN and PMMA were similar, both reaching approximate to 800N. The excellent anti-pullout property of CPN clearly suggests its potential for replacing PMMA in the application of cannulated pedicle-screw fixation, worth further study and development for clinical uses.
