Lenke3型成人特发性脊柱侧凸有限元模拟手术建模:5年2次建模评估

Finite element simulation surgical modeling of Lenke 3 adult idiopathic scoliosis:modeling evaluation twice in 5 years

背景:成人特发性脊柱侧凸是临床上常见的导致成人脊柱畸形的疾患,手术矫形为治疗该疾病的有效手段,但手术时机以及手术矫形策略的选择却对临床医生提出了挑战。目的:分别于5年前、后对同一位Lenke3型成人特发性脊柱侧凸志愿者进行脊柱有限元建模并模拟矫形手术,以了解该类型成人脊柱侧凸的疾病进展、脊柱和内植物的生物力学变化特点以及不同矫形术式矫形效果的变化,为该类型疾病的治疗提供数据参考。方法:选择典型的Lenke3型成人特发性脊柱侧凸志愿者1例为研究对象,男性,28岁,对该志愿者的脊柱进行连续CT扫描,将得到的原始图像导入至有限元软件中进行建模,对该模型进行进一步清理、优化后建立完整的包括胸廓结构在内的Lenke3型成人特发性脊柱侧凸有限元模型,并在此模型上分别进行有限元手术模拟,Case1:后路上端椎至下端椎双侧置钉、去除相应节段后路关节囊以达到关节松解的目的;Case2:后路关键椎置钉、去除相应节段后路关节囊进行关节松解;Case3:后路关键椎置钉、去除相应节段后路关节囊、松解前路侧凸处的胸椎;Case4:后路关键椎置钉、去除相应节段后路关节囊、松解前路侧凸处的腰椎;Case5:后路关键椎置钉、去除相应节段后路关节囊、松解前路侧凸处的胸、腰椎。5年后再次对该志愿者的脊柱侧凸进行有限元建模、模拟手术,以了解5年后该志愿者的疾病进展、脊柱和内植物的生物力学变化特点以及不同矫形术式矫形效果的变化。结果与结论:①在5年后建立的脊柱侧凸模型上,顺利完成了Case1-Case5手术矫形方案。各手术方案对胸椎侧凸的矫形率为56.8%,48.9%,49.8%,55.9%,57.0%,腰椎侧凸的矫形率为33.0%,36.9%,29.4%,30.0%,34.3%。Case3、5模拟手术矫形效果均较5年前下降明显,同时最大螺钉应力区域与最小螺钉应力区域均不同。②该Lenke3型成人特发性脊柱侧凸志愿者随着年龄的增长腰椎侧凸畸形发生增加,胸椎侧凸则无明显进展;5年后各手术方案对该志愿者胸、腰椎侧凸的矫形率以及矫形效果均下降明显,同时各术式下的螺钉应力最大区域也发生了变化。

BACKGROUND:Adult idiopathic scoliosis is a common clinical disease leading to adult spinal deformity.Surgical correction is an effective means to treat the disease,but the choice of surgical timing and surgical correction strategy poses a challenge to clinicians.OBJECTIVE:To follow up the same Lenke 3 adult idiopathic scoliosis volunteer and carry out finite element modeling and simulated posterior orthopedic surgery before and after 5 years,so as to understand the disease progression of this type of adult scoliosis,the biomechanical changes of spinal column and implant,and the changes of orthopedic effects of different orthopedic methods,and to provide data reference for the treatment of this type of disease.METHODS:A typical Lenke 3 adult idiopathic scoliosis volunteer,male,aged 28 years old,was selected as the research object.The volunteer’s spine was scanned by continuous CT.The original image was imported into the finite element software for modeling,and the model was further cleaned.After optimization,a complete Lenke 3 adult idiopathic scoliosis finite element model including thoracic structure was established,and finite element surgical simulation was carried out on this model.Case 1:bilateral screw placement from the upper to lower vertebrae and removal of the corresponding posterior joint capsule to achieve the purpose of joint release;Case 2:posterior key vertebrae were nailed and the corresponding segments of posterior joint capsule were removed for joint release;Case 3:posterior key vertebra nailing,removal of posterior joint capsule of corresponding segments,and release of thoracic vertebrae at anterior scoliosis;Case 4:posterior key vertebra nailing,removal of posterior joint capsule of corresponding segments,and release of lumbar spine at anterior scoliosis;Case 5:posterior key vertebra nailing,removal of posterior joint capsule of corresponding segments,and release of the thoracic and lumbar spine at the anterior scoliosis.Five years later,the volunteer’s scoliosis was modeled again by finite element method and simulated surgery,so as to understand the disease progression,biomechanical changes of spine and implant,and the changes of orthopedic effects of different orthopedic methods.RESULTS AND CONCLUSION:(1)On the scoliosis model established five years later,the surgical correction scheme for Case 1-Case 5 was successfully completed.The correction rates of thoracic scoliosis were 56.8%,48.9%,49.8%,55.9%,and 57.0%,and the correction rates of lumbar scoliosis were 33.0%,36.9%,29.4%,30.0%,and 34.3%.The orthopedic effects of simulated surgery of Cases 3 and 5 were significantly lower than those 5 years ago.At the same time,the maximum screw stress area and the minimum screw stress area were different.(2)The lumbar scoliosis deformity of Lenke 3 adult idiopathic scoliosis volunteers increased with age,but there was no significant progress in thoracic scoliosis.Five years later,the correction rate and effect of each operation scheme on thoracic and lumbar scoliosis decreased significantly,and the area with the largest screw stress under each operation also changed.