Torsional stiffness of a single-rod construct using three instrumentation systems for thoracic scoliosis

Three instrumentation systems were tested using a unilateral rod construct for instrumenting thoracic scoliosis. Thoracic calf spines were instrumented with Texas Scottish Rite Hospital (TSRH), Cotrel Dubousset (CD), and Isola single-rod instrumentation systems. The constructs were mechanically tested, and rotational displacement and torsional stiffness were determined. The TSRH instrumentation was found to have significantly less rotational displacement and to be significantly stiffer in torsion than the uninstrumented control. The CD and Isola systems were not significantly different than the uninstrumented calf spine.