A transpedicularly implanted anterior spinal support

This article describes a device that has been developed to augment posterior spinal fracture fixation by providing support for the anterior column of the spine. The device is contracted for insertion through the limited opening provided by the transpedicular approach to the vertebral body. Once in situ it is configured to support physiological loads. In this way the structural limitations of posterior instrumentation and the surgical difficulties of anterior spinal fixation instrumentation are overcome. A preliminary investigation of the new device together with in vitro studies of a prototype are described in this report. In vitro tests to determine the expansion characteristics and structural performance of the device were performed together with tests to determine the efficacy of the support to reduce loading on the posterior fixation device. It is shown that the device has the necessary expansion characteristics and can support physiological loads without failure. Tests using porcine vertebral columns with a simulated vertebral fracture showed a significant reduction in load carried by the posterior fixation plates (44 +/- 16%) when the anterior support was included in the construct. In addition, the difference in loading between the left and right plates was significantly reduced (81 +/- 12%).