A protocol to evaluate semi-rigid pedicle screw systems.

The objective of the current study was to develop an in vitro testing protocol to evaluate semi-rigid pedicle screw devices. A corpectomy model protocol exists to evaluate rigid spinal implants; however, semi-rigid devices are contraindicated for this condition. This paper describes a technique that simulates more closely the conditions a semi-rigid device would see in vivo. Finally, the new testing protocol is used to evaluate the DDS pedicle screw-cable system. Benefits and shortcomings of the new protocol are discussed.