TY - JOUR
T1 - Design, synthesis, imaging, and biomechanics of a softness-gradient hydrogel nucleus pulposus prosthesis in a canine lumbar spine model
AU - Kranenburg, Hendrik-Jan C.
AU - Meij, Bjorn P.
AU - Onis, David
AU - van der Veen, Albert J.
AU - Saralidze, Ketie
AU - Smolders, Luc A.
AU - Huizinga, Julie G.
AU - Knetsch, Menno L. W.
AU - Luijten, Peter R.
AU - Visser, Fredy
AU - Voorhout, George
AU - Dhert, Wouter J. A.
AU - Hazewinkel, Herman A. W.
AU - Koole, Leo H.
PY - 2012/11
Y1 - 2012/11
N2 - A hydrogel nucleus pulposus prosthesis (NPP) was designed to swell in situ, have intrinsic radiopacity, and restore intervertebral disc height and biomechanical functionality. These features were examined using an ex vivo canine lumbar model. Nine NPPs were implanted in five spines and their visibility was assessed on radiography, computed tomography (CT), and magnetic resonance imaging (MRI). The NPPs were visible on all imaging modalities and 8/9 NPPs stayed intact and in situ. Six other NPPs were tested biomechanically in six canine lumbar spines. Removal of the nucleus pulposus (nuclectomy) caused significant changes in biomechanical parameters. After implantation and swelling of the NPP, values were not significantly different from the native state for range of motion (ROM) of flexion-extension (FE) and lateral bending (LB), the neutral zone (NZ) of all motion directions, and the NZ stiffness (NZS) of FE. Biomechanical restoration by the NPP compared with the nuclectomized state was significant for the ROM of FE and axial rotation, the NZ of FE and LB, and the NZS of FE and LB. Disc height was significantly restored and 6/6 NPPs stayed intact and in situ. In conclusion, the NPPs swell in situ, have intrinsic radiopacity and restored disc height and aforementioned biomechanical properties.
AB - A hydrogel nucleus pulposus prosthesis (NPP) was designed to swell in situ, have intrinsic radiopacity, and restore intervertebral disc height and biomechanical functionality. These features were examined using an ex vivo canine lumbar model. Nine NPPs were implanted in five spines and their visibility was assessed on radiography, computed tomography (CT), and magnetic resonance imaging (MRI). The NPPs were visible on all imaging modalities and 8/9 NPPs stayed intact and in situ. Six other NPPs were tested biomechanically in six canine lumbar spines. Removal of the nucleus pulposus (nuclectomy) caused significant changes in biomechanical parameters. After implantation and swelling of the NPP, values were not significantly different from the native state for range of motion (ROM) of flexion-extension (FE) and lateral bending (LB), the neutral zone (NZ) of all motion directions, and the NZ stiffness (NZS) of FE. Biomechanical restoration by the NPP compared with the nuclectomized state was significant for the ROM of FE and axial rotation, the NZ of FE and LB, and the NZS of FE and LB. Disc height was significantly restored and 6/6 NPPs stayed intact and in situ. In conclusion, the NPPs swell in situ, have intrinsic radiopacity and restored disc height and aforementioned biomechanical properties.
KW - hydrogel
KW - softness gradient
KW - nucleus pulposus replacement
KW - intervertebral disc
KW - radiopacity
U2 - 10.1002/jbm.b.32780
DO - 10.1002/jbm.b.32780
M3 - Article
C2 - 22888039
SN - 1552-4973
VL - 100B
SP - 2148
EP - 2155
JO - Journal of Biomedical Materials Research Part B-applied Biomaterials
JF - Journal of Biomedical Materials Research Part B-applied Biomaterials
IS - 8
ER -