TY - JOUR
T1 - Self-deploying shape memory polymer scaffolds for grafting and stabilizing complex bone defects
T2 - A mouse femoral segmental defect study
AU - Baker, Richard M.
AU - Tseng, Ling Fang
AU - Iannolo, Maria T.
AU - Oest, Megan E.
AU - Henderson, James H.
N1 - Funding Information:
The authors gratefully thank Professor Patrick Mather for sharing professional advice. The authors would also like to thank Fred Donelson and Nick Zimmerman for their assistance in intraperitoneal ketamine injections and wound clip removal, respectively. This work is sponsored by DARPA ( DP12AP00271 to JHH), and the content of the information does not necessarily reflect the position or the policy of the Government, and no endorsement should be inferred. Appendix A
Publisher Copyright:
© 2015 Elsevier Ltd.
PY - 2016
Y1 - 2016
N2 - Treatment of complex bone defects places a significant burden on the US health care system. Current strategies for treatment include grafting and stabilization using internal metal plates/screws, intramedullary rods, or external fixators. Here, we introduce the use of shape memory polymer (SMP) materials for grafting and adjunct stabilization of segmental defects. Self-deploying SMP grafts and SMP sleeves capable of expanding and contracting, respectively, under intraoperative conditions were developed and evaluated in a mouse segmental defect model in vivo. Integration between grafts/sleeves and native bone was assessed using x-ray radiography, microcomputed tomography, and torsional mechanical testing. We found that SMP grafts were able to integrate with the native bone after 12 weeks, maintain defect stability, and provide torsional mechanical properties comparable to an allograft alone treatment; however no gross de novo bone formation was observed. SMP sleeves did not inhibit bony bridging at the margins, and limbs treated with a sleeve/allograft combination had torsional mechanical properties comparable to limbs treated with an allograft alone. In vitro torsional and bending tests suggest sleeves may provide additional torsional stability to defects. Incorporation of shape memory into synthetic bone graft substitutes and adjunct stabilization devices is anticipated to enhance functionality of synthetic materials employed in both applications.
AB - Treatment of complex bone defects places a significant burden on the US health care system. Current strategies for treatment include grafting and stabilization using internal metal plates/screws, intramedullary rods, or external fixators. Here, we introduce the use of shape memory polymer (SMP) materials for grafting and adjunct stabilization of segmental defects. Self-deploying SMP grafts and SMP sleeves capable of expanding and contracting, respectively, under intraoperative conditions were developed and evaluated in a mouse segmental defect model in vivo. Integration between grafts/sleeves and native bone was assessed using x-ray radiography, microcomputed tomography, and torsional mechanical testing. We found that SMP grafts were able to integrate with the native bone after 12 weeks, maintain defect stability, and provide torsional mechanical properties comparable to an allograft alone treatment; however no gross de novo bone formation was observed. SMP sleeves did not inhibit bony bridging at the margins, and limbs treated with a sleeve/allograft combination had torsional mechanical properties comparable to limbs treated with an allograft alone. In vitro torsional and bending tests suggest sleeves may provide additional torsional stability to defects. Incorporation of shape memory into synthetic bone graft substitutes and adjunct stabilization devices is anticipated to enhance functionality of synthetic materials employed in both applications.
KW - Internal fracture fixation
KW - Mouse model
KW - Segmental defect
KW - Shape memory polymer
KW - Synthetic bone graft
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U2 - 10.1016/j.biomaterials.2015.10.064
DO - 10.1016/j.biomaterials.2015.10.064
M3 - Article
C2 - 26561935
AN - SCOPUS:84961226458
SN - 0142-9612
VL - 76
SP - 388
EP - 398
JO - Biomaterials
JF - Biomaterials
ER -