Torsional stiffness of three spine constructs for thoracic scoliosis

The standard two-rod thoracic scoliosis construct is bulky in the thin, young patient. A single-rod construct with hooks at every level was developed. Five calf spines were tested measuring angular displacement before and after instrumentation using three scoliosis constructs: a standard two-rod construct, a single-rod construct, and a single-rod construct with crossover hooks. Rotational displacements and stiffness were compared. There was no statistical difference in rotational displacement or stiffness among the three constructs. All three constructs were significantly stiffer in torsion than the uninstrumented control. The single-rod construct and the crossover construct may offer the spine surgeon additional options in instrumenting thoracic scoliosis, if our preliminary studies are verified by others.