Jin Luo, Phillip Pollintine, Edward Gomm, Patricia Dolan, Michael A. Adams


September 2012, Volume 21, Issue 9, pp 1684 - 1691 Original Article Read Full Article 10.1007/s00586-012-2279-y

First Online: 25 March 2012

Introduction

Vertebral deformities often occur in patients who recall no trauma, and display no evident fracture on radiographs. We hypothesise that vertebral deformity can occur by a gradual creep mechanism which is accelerated following minor damage. “Creep” is continuous deformation under constant load.

Materials and methods

Forty-five thoracolumbar spine motion segments were tested from cadavers aged 42–92 years. Vertebral body areal BMD was measured using DXA. Specimens were compressed at 1 kN for 30 min, while creep in each vertebral body was measured using an optical MacReflex system. After 30 min recovery, each specimen was subjected to a controlled overload event which caused minor damage to one of its vertebrae. The creep test was then repeated.

Results

Vertebral body creep was measurable in specimens with BMD

Conclusions

Minor damage to an old vertebral body, even if it is barely discernible on radiographs, can accelerate creep to such an extent that it makes a substantial contribution to vertebral deformity.


Read Full Article