Computer simulation for the optimization of instrumentation strategies in adolescent idiopathic scoliosis

Recent studies reveal a large variability of instrumentation strategies in adolescent idiopathic scoliosis (AIS). Determination of the optimal configuration remains controversial. This study aims to develop a method to define the optimal surgical instrumentation strategy using a computer model implemented in a spine surgery simulator (S3). A total of 702 different strategies were simulated on a scoliotic patient using S3. Each configuration was assessed using objective functions that represented different correction objectives. Twelve geometric parameters were used in the three anatomic planes and mobility, and their relative weights were defined by a spine surgeon according to his objectives for correction of scoliosis. Six instrumentation parameters were manipulated in a uniform experimental design framework. An interpolation technique was used to build an approximation model from the simulation results and to locate instrumentation parameters minimizing the objective function. Small or no differences in the correction between the simulated optimal strategy and the real postoperative results of the instrumented segments were observed in the three planes. But the same overall correction was obtained by using fewer implants (only screws) and less instrumented levels. This study demonstrates the potential and feasibility of using a spine surgery simulator to optimize the planning of surgical instrumentation in AIS.