Three-dimensional finite element simulation of surgical correction for Lenke 2 type adolescent idiopathic scoliosis

Abstract

Objective To simulate different anterior and posterior correction strategies using finite element model of Lenke 2 type adolescent idiopathic scoliosis(AIS),in an effort to seek the optimal surgical protocol.Methods The finite element model of Lenke 2 type AIS was established and used to simulate five surgical strategies.The effectiveness and shoulder balance parameters were compared among different surgical approaches.Results The coronary proximal thoracic(PT) Cobb angle and corrective rates of the five surgical strategies were 21.5(44.8%),26.5(32.1%),28.1(27.9%),34.1(12.5%),and 32(17.9%).The corrective rates for the main thoracic curves were not significantly different among the five strategies,and the physiological sagittal configuration was maintained.Postoperative radiographic shoulder balance parameters were increased for all five surgical protocols.Except for strategy A(posterior fusion from T2 to T11),other four strategy achieved the following outcomes: coracoid height difference9 mm,clavical angle2.5° and clavicular tilt angle difference4.5°.Conclusion Simulation of posterior correction and fusion to T2 including both thoracic curve can achieve excellent three-dimensional corrective results and balanced shoulders for Lenke 2 type AIS model with preoperative left elevated shoulder.Partial fusion of PT curves to T3 or T4 results in inferior corrective rate of PT curve and mild or moderate shoulder imbalance.Simulation of anterior or posterior selective main thoracic curve fusion has very low spontaneous PT corrective rate and can lead to deteriorated shoulder imbalance slight to moderate degrees.