Artificial Intervertebral Disc Replacement Using Bioactive Three-Dimensional Fabric: Design, Development, and Preliminary Animal Study

Study Design. 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. Objectives. 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. Summary of Background Data. 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. Conclusion. 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.

[1]  Saiwei Yang,et al.  Finite-Element Modeling of the Synthetic Intervertebral Disc , 1991, Spine.

[2]  N. Langrana,et al.  Materials and design concepts for an intervertebral disc spacer. II. Multidurometer composite design. , 1995, Journal of applied biomaterials : an official journal of the Society for Biomaterials.

[3]  S Etebar,et al.  Risk factors for adjacent-segment failure following lumbar fixation with rigid instrumentation for degenerative instability. , 1999, Journal of neurosurgery.

[4]  K. Ishikawa,et al.  Lateral Atlantoaxial Dislocation , 1991, Spine.

[5]  W. S. Zeegers,et al.  Artificial disc replacement with the modular type SB Charité III: 2-year results in 50 prospectively studied patients , 1999, European Spine Journal.

[6]  H. Kawarada,et al.  Potential application of a triaxial three-dimensional fabric (3-DF) as an implant. , 1998, Biomaterials.

[7]  R. Biscup,et al.  Artificial disc replacement. Preliminary report with a 3-year minimum follow-up. , 1993, Spine.

[8]  K Kaneda,et al.  The Mechanical Properties of the Human L4–5 Functional Spinal Unit During Cyclic Loading: The Structural Effects of the Posterior Elements , 1992, Spine.

[9]  Kiyoshi Kaneda,et al.  The Role of Spinal Instrumentation in Augmenting Lumbar Posterolateral Fusion , 1996, Spine.

[10]  K. Kaneda,et al.  Biomechanical Role of the Posterior Elements, Costovertebral Joints, and Rib Cage in the Stability of the Thoracic Spine , 1996, Spine.

[11]  H A Yuan,et al.  The artificial disc: theory, design and materials. , 1996, Biomaterials.

[12]  K. Büttner-Janz,et al.  Biomechanics of the SB Charité lumbar intervertebral disc endoprosthesis , 2004, International Orthopaedics.

[13]  CASEY K. LEE,et al.  Accelerated Degeneration of the Segment Adjacent to a Lumbar Fusion , 1988, Spine.

[14]  S. Boden,et al.  Spine update. The use of animal models to study spinal fusion. , 1994, Spine.

[15]  S. L. Griffith,et al.  A Multicenter Retrospective Study of the Clinical Results of the LINK®SB CharitéA Intervertebral Prosthesis. The Initial European Experience , 1994, Spine.

[16]  A. Schultz,et al.  Mechanical Properties of Human Lumbar Spine Motion Segments—Part I: Responses in Flexion, Extension, Lateral Bending, and Torsion , 1979 .

[17]  K Kaneda,et al.  The Effects of Spinal Fixation and Destabilization on the Biomechanical and Histologic Properties of Spinal Ligaments: An In Vivo Study , 1998, Spine.

[18]  F. Postacchini,et al.  Results of Disc Prosthesis After a Minimum Follow‐Up Period of 2 Years , 1996, Spine.

[19]  T. Hedman,et al.  Design of an Intervertebral Disc Prosthesis , 1991, Spine.

[20]  J W Frymoyer,et al.  A Comparison of Radiographic Findings in Fusion and Nonfusion Patients Ten or More Years Following Lumbar Disc Surgery , 1979, Spine.

[21]  F. M. Carter,et al.  Mechanical evaluation of a canine intervertebral disc spacer: In situ and In vivo studies , 1994, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[22]  K. Kaneda,et al.  Biomechanical role of the intervertebral disc and costovertebral joint in stability of the thoracic spine. A canine model study. , 1999, Spine.

[23]  H. Farfan,et al.  The effects of torsion on the lumbar intervertebral joints: the role of torsion in the production of disc degeneration. , 1970, The Journal of bone and joint surgery. American volume.

[24]  K. Kaneda,et al.  Biomechanical and Morphologic Evaluation of a Three-Dimensional Fabric Sheep Artificial Intervertebral Disc: In Vitro and In Vivo Analysis , 2001, Spine.