International Journal of Nanomedicine (Apr 2017)

A novel injectable calcium phosphate-based nanocomposite for the augmentation of cannulated pedicle-screw fixation

  • Sun H,
  • Liu C,
  • Liu H,
  • Bai Y,
  • Zhang Z,
  • Li X,
  • Li C,
  • Yang H,
  • Yang L

Journal volume & issue
Vol. Volume 12
pp. 3395 – 3406

Abstract

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Haolin Sun,1,* Chun Liu,2,* Huiling Liu,2,* Yanjie Bai,3 Zheng Zhang,1 Xuwen Li,1 Chunde Li,1 Huilin Yang,2,4 Lei Yang2,4 1Department of Orthopedics, Peking University First Hospital, Beijing, 2Department of Orthopedics, Institute of Orthopedics, First Affiliated Hospital, 3School of Public Health, Medical College, 4International Research Center for Translational Orthopedics (IRCTO), Soochow University, Suzhou, China *These authors contributed equally to this work Abstract: Polymethyl methacrylate (PMMA)-augmented cannulated pedicle-screw fixation has been routinely performed for the surgical treatment of lumbar degenerative diseases. Despite its satisfactory clinical outcomes and prevalence, problems and complications associated with high-strength, stiff, and nondegradable PMMA have largely hindered the long-term efficacy and safety of pedicle-screw fixation in osteoporotic patients. To meet the unmet need for better bone cement for cannulated pedicle-screw fixation, a new injectable and biodegradable nanocomposite that was the first of its kind was designed and developed in the present study. The calcium phosphate-based nanocomposite (CPN) exhibited better anti-pullout ability and similar fluidity and dispersing ability compared to clinically used PMMA, and outperformed conventional calcium phosphate cement (CPC) in all types of mechanical properties, injectability, and biodegradability. In term of axial pullout strength, the CPN-augmented cannulated screw reached the highest force of ~120 N, which was higher than that of PMMA (~100 N) and CPC (~95 N). The compressive strength of the CPN (50 MPa) was three times that of CPC, and the injectability of the CPN reached 95%. In vivo tests on rat femur revealed explicit biodegradation of the CPN and subsequent bone ingrowth after 8 weeks. The promising results for the CPN clearly suggest its potential for replacing PMMA in the application of cannulated pedicle-screw fixation and its worth of further study and development for clinical uses. Keywords: calcium phosphate nanocomposite, injectable, biodegradable, pedicle screw, lumbar degenerative disease, osteoporosis

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