Comparison of allograft bone and titanium cages for vertebral body replacement in the thoracolumbar spine: a biomechanical study

Neurosurgery. 2010 Jun;66(6 Suppl Operative):314-8; discussion 318. doi: 10.1227/01.NEU.0000370200.74098.CC.

Abstract

Background: When an anterior approach to repair a burst fracture is indicated, several devices can be used to restore spinal stability (eg, bone graft, free-standing titanium cage, and expandable titanium cage).

Objective: We compare the biomechanical stability and prices of each of these systems.

Materials and methods: Eight fresh human cadaver T11 through L3 vertebral specimens were harvested and cleaned of soft tissues. T11-T12 and L2-L3 were fixed by screws. The fixed ends were then set in automotive body filler (Bondo). The prepared specimens were tested in the Biaxial Instron tester (8874, Norwood, MA) after a sequence of the following: intact, after the creation of an anterior corpectomy at L1, and after insertion of both of the 2 different titanium cages and the fibular graft. A titanium screw-and-plate anterolateral system was used to secure the construct (VANTAGE, Medtronic Sofamor Danek, Memphis, TN). The conditions of displacement testing were as follows: rotation (+/- 3.5 degrees ), flexion and extension, and left and right bending (+/- 3.5 mm). For each mode of testing, the stiffness was calculated.

Results: The stiffness data, when statistically analyzed by repeated-measures analysis of variance (at P = .05 and power > 0.9), indicated no significant differences among these devices.

Conclusion: On the basis of this biomechanical study, the stiffness of the fibular graft was similar to that of the other metallic devices in this cadaver model.

Publication types

  • Comparative Study

MeSH terms

  • Biomechanical Phenomena
  • Bone Transplantation / methods*
  • Cadaver
  • Equipment Design / methods
  • Equipment Failure Analysis / methods
  • Humans
  • Lumbar Vertebrae / pathology
  • Lumbar Vertebrae / physiopathology
  • Lumbar Vertebrae / surgery*
  • Models, Anatomic
  • Prostheses and Implants / standards
  • Prosthesis Implantation / methods*
  • Spinal Fractures / pathology
  • Spinal Fractures / physiopathology
  • Spinal Fractures / surgery*
  • Spinal Fusion / instrumentation
  • Spinal Fusion / methods*
  • Thoracic Vertebrae / pathology
  • Thoracic Vertebrae / physiopathology
  • Thoracic Vertebrae / surgery*
  • Titanium / therapeutic use
  • Transplantation, Homologous / methods

Substances

  • Titanium