Creep Deformity of Human Vertebrae

INTRODUCTION: In many elderly people, one or more vertebrae lose height, especially anteriorly. Such anterior “wedge” deformities lead to senile kyphosis a condition that can cause pain, disability and loss of self-esteem. Metabolic processes weaken elderly bone, and altered load-sharing in the elderly spine causes mechanical damage to be concentrated in the anterior vertebral body (1). The resulting deformities are often referred to as “fractures”, but the insidious onset of many vertebral deformities suggests that gradual time-dependent “creep” processes can also contribute. Bone is known to have viscoelastic properties (2), but creep deformity of whole vertebrae has not previously been investigated. We hypothesise that creep processes can contribute to anterior wedge deformity in elderly human vertebrae.