Artificial intervertebral disc replacement using bioactive three-dimensional fabric: design, development, and preliminary animal study.
METHODS
A new artificial intervertebral disc was developed, and its intrinsic biomechanical properties, bioactivity, and the effectiveness as a total disc replacement were evaluated in vitro and in vivo.


OBJECTIVE
To introduce a new artificial intervertebral disc and to evaluate the in vitro mechanical properties, fusion capacity to bone, and segmental biomechanics in the total intervertebral disc replacement using a sheep lumbar spine.


BACKGROUND
The loss of biologic fusion at the bone-implant interface and prosthetic failures have been reported in previous artificial discs. There have been no clinically applicable discs with detailed experimental testing of in vivo mechanics and interface fusion capacity.


METHODS
The artificial intervertebral disc consists of a triaxial three-dimensional fabric (3-DF) woven with an ultra-high molecular weight polyethylene fiber, and spray-coated bioactive ceramics on the disc surface. The arrangement of weave properties was designed to produce mechanical behavior nearly equivalent to the natural intervertebral disc. Total intervertebral disc replacement at L2-L3 and L4-L5 was performed using 3-DF disc with or without internal fixation in a sheep lumbar spine model. The segmental biomechanics and interface histology were evaluated after surgery at 4 and 6 months.


RESULTS
The tensile-compressive and torsional properties of prototype 3-DF were nearly equivalent to those of human lumbar disc. The lumbar segments replaced with 3-DF disc alone showed a significant decrease of flexion-extension range of motion to 28% of control values as well as partial bony fusion at 6 months. However, the use of temporary fixation provided a nearly physiologic mobility of the spinal segment after implant removal as well as excellent bone-disc fusion at 6 months.


CONCLUSIONS
An artificial intervertebral disc using a three-dimensional fabric demonstrated excellent in vitro and in vivo performance in both biomechanics and interface histology. There is a potential for future clinical application.
Kotani
Yoshihisa
Y
Department of Orthopaedic Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Japan. y-kotani@med.hokudai.ac.jp
Abumi
Kuniyoshi
K
Shikinami
Yasuo
Y
Takada
Takashige
T
Kadoya
Ken
K
Shimamoto
Norimichi
N
Ito
Manabu
M
Kadosawa
Tsuyoshi
T
Fujinaga
Toru
T
Kaneda
Kiyoshi
K
D000818:Animals; D001696:Biomechanical Phenomena; D020099:Coated Materials, Biocompatible; D020007:Implants, Experimental / Q000592:standards / Q000706:statistics & numerical data; D007403:Intervertebral Disc / Q000601:surgery*; D008854:Microscopy, Electron; D023421:Models, Animal; D019637:Orthopedic Procedures / Q000295:instrumentation*; D020959:Polyethylene; D011312:Pressure; D016059:Range of Motion, Articular; D012756:Sheep; D016896:Treatment Outcome; D016474:Weight-Bearing
D020099:Coated Materials, Biocompatible; D020959:Polyethylene