Analysis on mechanical property of remedy for scoliosis by PRSS / 中国矫形外科杂志

ABSTRACT

[Objective] Scoliosis with wedging of vertebra and open-up disc space over convex side can be reversed when PRSS(plate-rod system for scoliosis)was applied.In order to study the mechanical properties of the remedy for the scoliosis by PRSS,the photoelastic test was performed.[Method] The model that consists of five vertebra bodies and four intervertebral discs was built with aluminum and polycarbonate,thus the situation of low-grade scoliosis was simulated.The axial stress was loaded 0 kg,5kg,10 kg,15 kg,20 kg respectively,and the lateral side load was 0 kg,3 kg,6 kg,9 kg,and 12 kg respectively over the spinal column.According to the factual situation,the in-situ stress was measured by using photoelastic and strain gage method.ANSYS9.0 method was also applied to simulate the experiment process and evaluate the reliability of measurement.[Result]When PRSS was placed in,compressive stress was found to exert on the convex side whereas tensile stress was found on the concave side of the curvature,thus modulating bony growth of spinal vertebra,resulted in spinal column realignment.[Conclusion]The PRSS is an effective device to treat the scoliosis of the patients,especially in young children,because it not only can correct the deformity but also allows extension along with the children's growth.