New spinal instrumentation and a study of its kinetics

The new system described here is a segmental square spinal instrumentation (termed 3-S) for spinal fusion. To estimate the strength of this instrumentation, compression, flexion and torsional strength were tested and compared with that of the conventional instrumentation of Harrington or Luque with the following results; In the compression and flexion tests, the 3-S instrumentation models are mechanically stronger but inflexible, and has less deformation than the other types. In the torsion test, with regard to the moment and the torsion angle at the time of breakage of spinal models, the 3-S type was ranked between the Harrington and Luque types. Those results suggested clinical usefulness for improving spinal stability.