The pain of vertebral compression fractures can arise in the posterior elements.

OBJECTIVES To describe and test a model to explain the biomechanical basis for persistent pain after compression fractures of the vertebral body. METHODS The biomechanics model was derived axiomatically from a consideration of the anatomy of vertebral column when affected by compression fractures. Proof of principle was provided by performing controlled diagnostic blocks in six patients. RESULTS The biomechanics model shows that the posterior elements of the vertebral column must subluxate cephalad or caudad in response to deformity of a vertebral body. The model implies that pain may arise from the posterior elements, and predicts that anesthetizing the posterior elements should relieve the pain of compression fractures. Six cases are described in which controlled medial branch blocks relieved the pain of compression fractures of thoracic or lumbar vertebral bodies. CONCLUSIONS In some patients with vertebral compression fractures, the pain may arise from posterior elements and not the fracture itself. This phenomenon has implications for the interpretation of the outcomes of vertebroplasty in both the active and control arms of sham-controlled studies.