J Korean Soc Spine Surg.  1999 Dec;6(3):344-348.

Effect of Bone Mineral Density and Endplate Thickness on the Compressive Strength in the Cervical Spine

• Kwon H
• An HS
• Lim TH
• Jeon CH

Abstract

STUDY DESIGN: This is a biomechanical study to evaluate the subsidence at the cervical endplate from seven fresh cadavers. The study performed after evaluating a bone mineral density(BMD) and a thickness of the endplate.
OBJECTIVES
To evaluate the effect of BMD and endplate thickness on the biomechanical strength in an anterior cervical interbody fusion model. MATERIAL AND METHODS: A total of 7 cervical spines(C3-C7) were obtained from fresh cadavers and dissected through the intervertebral disc to obtain the isolated vertebrae. BMD of each vertebral body was measured using a dual-energy x-ray absorptiometry(DEXA) and thickness of endplates was measured by CT images. Each vertebral body was cut into halves through the horizontal plane and prepared specimens were assigned one of the following 3 groups so that group mean BMDs became similar. In group 1, the endplates were preserved intact. The endplates in group 2 were burred into approximately 1/2 of the intact thickness. In group 3, the endplates were totally removed. Each specimen underwent the destructive compression test by using an Instron material test system(MTS).
RESULTS
There was significant linea relationship between BMD and load to failure. The load to failure of group 1 was significantly greater than group 3.
CONCLUSION
Preoperative consideration of BMD would be important for patient selection and the choice of a surgical technique. And it may be important to preserve the endplate as much as possible to reduced the incidence of subsidence when performing the cervical interbody fusion.

Keyword

Cervical spine; Endplate; BMD; Subsidence

MeSH Terms

Bone Density*
Cadaver
Compressive Strength*
Incidence
Intervertebral Disc
Patient Selection
Spine*