【作者】 郑国权；

【导师】 王岩；

【作者基本信息】 中国人民解放军军医进修学院 ， 外科学， 2010， 博士

【摘要】 研究背景到目前为止,对于僵硬的脊柱侧凸患者,节段内全椎弓根螺钉技术的三维矫形效果已获得大大提高。但是,如果采用僵硬的钛棒,在严重脊柱侧凸患者的顶椎区域,容易出现一些并发症,如很难将僵硬的钛棒与椎弓根钉相连,应力集中,椎弓根钉拔出等并发症。另一方面,形状记忆合金在低温时较柔软,而当给予适当的温度,高于其相变温度时,将恢复到原始形状。该形变过程可用于辅助脊柱侧凸的矫形。尽管我们于2002年五月就开始采用形状记忆合金来行脊柱侧凸矫形手术,但目前尚无相关的生物力学分析,对既往的病例的临床及影像学效果也没有进行系统的回顾分析,对椎体的去旋转效果也没有进行量化研究。目的1.采用有限元分析的方法,对基于形状记忆合金脊柱侧凸矫形进行生物力学分析。2.对在我院采用形状记忆合金矫形的脊柱侧凸患者进行回顾性研究,评价该技术的临床及影像学结果；在矫治严重脊柱侧凸患者时,通过与传统僵硬的钛棒进行比较,探讨形状记忆合金的优势。3．前瞻性研究基于形状记忆合金的脊柱侧凸矫形方法在去旋转方面的效果方法1.采用患者脊柱的三维有限元模型模拟形状记忆合金棒矫治1例特发性脊柱侧凸病例。有限元模型的几何模型摘自三维CT重建,力学性能及参数通过查阅文献所得。基于形状记忆合金棒脊柱侧凸矫形的主要步骤都进行模拟,并将模拟计算结果与术后真实的CT重建结果进行比对。2.从2002年5月到2006年9月,在我院采用形状记忆合金矫治的38例脊柱侧凸患者(弯曲范围：50°到120°,其中22例患者超过70°)进行回顾性分析。在矫形过程中,形状记忆合金棒作为临时矫形工具,完成矫形后,用坚硬的钛合金棒进行替换。矫治效果,手术时间,出血量,并发症等均一一登记。对于严重的脊柱侧凸患者病例,选取弯曲类型,手术时的年龄,手术方法,融合节段与之相匹配的病例进行比较,SMA组14例,传统矫形技术16例。3.自2007年9月到2009年3月,前瞻性研究采用节段椎弓根钉内固定的患者30例,其中第一组(n=14)采用形状合金棒进行矫治,该组患者中主弯位于胸段的8例,腰段6例。第二组(n=16)采用单纯转棒技术,该组患者主弯位于胸段的9例,位于腰段的7例。所有患者均行术前术后CT检查评估顶椎椎体旋转。结果1.模拟结果显示基于形状记忆合金的脊柱侧凸矫形是一个真正的三维矫形技术,在该技术中,椎体被矫形的方向包括,冠状面、矢状面和轴向面。2.主弯Cobb角由术前的平均78.4°矫正到24.3°(整体矫正率为71.4%),16例主弯<70°,柔软系数为52.7%,术前Cobb角平均58.4°矫正到12.3°(矫正率78.9%)；在22例主弯大于70°的患者,其柔软系统为25.6%,术前Cobb角平均94.1°矫正到30.1°(矫正率68.1%)；在队列研究中,在SMA组,术前Cobb角平均92.6°,柔软系数25.5%,被矫正到29.4°,矫正率为68.4%。传统组,术前Cobb角平均88.6°,柔软系数29.3%,被矫正到37.2°,矫正率为57.8%。两组之间在冠状面上具有统计学差异。3.对主弯位于胸椎的患者,其中SMA组,术前AVR为16.2°矫正到7.5°,矫正率为50.4%。而转棒组从15.3°矫正到9.9°(34.8%),两组之间具有统计学差异(p<0.05)；对主弯位于腰椎的患者,其中SMA组,术前AVR为26.2°矫正到13.7°,矫正率为47.6%。而转棒组从25.4°矫正到14.5°(42.8%),两组之间没有统计学差异(p>0.05)；结论1.基于形状记忆合金棒的脊柱侧凸矫形是一个真正的三维矫形技术。2.术中临时应用形状记忆合金棒是一个安全有效的矫正脊柱侧凸的方法。术中临时应用记忆棒可减少手术时间,减少出血量,降低椎弓根失败的风险,同时提高在冠状面上的矫正率。3.基于形状记忆合金的脊柱侧凸矫形可提高胸椎的去旋转效果,而不能提高腰椎的去旋转效果。更多还原

【Abstract】 BackgroundTill now, the 3-demetional correction effects of severe rigid scoliosis were improved by whole segmental pedicle screws instruments. But, some shortcomings relate to the regular rigid rod, especially in the apex region of severe scoliosis, are obviously, such as the difficult of placing rigid rod into whole segmental pedicle screws, the concentration of stress, the pull-out of pedicle screws etc. On the other hand, shape memory spinal rod is characterized by its mallealbility at low temperatures and its ability to return to a preconfigured shape above its activation temperature. This process can be utilized to assist in the scoliosis correction. Though serial scoliosis patients were performed spinal correction with shape memory alloy from May,2002, no in vitro biomechanical analysis of the technique was performed, no systematic review was performed to envalue the clinical and radiographic effects, and no quantitative study was performed to evaluate the derotation effect.Objectives.1. A biomechanical analysis of shape memory alloy based scoliosis correction was performed by finite element analysis.2. A retrospective study of scoliosis patients that underwent shape memory alloy rod assisted correction was performed to evaluate the clinical and radiographic results of a temporary shape memory alloy rod in the correction of scoliosis, and the advantages of shape memory alloy rod were evaluated by comparing the clinical and radiographic results obtained from temporary using of shape memory alloy rod and those from rigid rod in the correction of severe scoliosis.3. A prospective study of shape memory alloy based scoliosis correction was performed to envaluate the derotation effects by comparing to single rod derotation.Methods.1. Shape memory alloy based scoliosis correction was simulated for 1 patient with idiopathic scoliosis using 3D finite element model (FEM) of the patient’s entire spine. The geometry of the FEM was extracted from a 3D CT scan reconstruction, and mechanical properties were personalized from literatures. The main step of shape memory based scoliosis correction was simulated and the results were compared with the postoperative 3D CT scan reconstruction.2. From May 2002 to Sep 2006,38 scoliosis patients (range from 50°to 120°,22 cases over 70°) that underwent shape memory alloy assisted correction in our institute were reviewed. During the operation, a shape memory alloy rod served as a temporary correction tool. Following correction, the rod was replaced by a rigid rod. The correction rate, operative time, blood loss, and complications were documented. Patients with matched curve type, ages at surgery, operative methods, and fusion levels in our institute were instrumented with shape memory alloy rods (SMA) (n=14) and traditional correction techniques (n=16) were compared.3. From Sep 2007 to Mar 2009,30 patients with scoliosis were treated with segmental pedicle screw fixation were analyzed. The first group (n=14) was corrected by shape memory alloy, the major curve the patients located at thoracic spine in 8 patients, at lumbar spine in 6 patients. The second group (n=16) was treated by simple rod derotation, the major curve the patients located at thoracic spine in 9 patients, at lumbar spine in 7 patients. Both groups were evaluated for the deformity correction in coronal plane and sagittal plane, and the apical vertebral rotation was evaluated by computed tomography scans.Results.1. The results of simulation show that the shape memory alloy based scoliosis correction is a real 3D technique, in which the vertebrae were corrected in coronal plane, sagittal plane, and the axial plane.2. The major Cobb angle improved from an average 78.4°preoperatively to 24.3°postoperatively (total percent correction 71.4%). In 16 patients with a major curve <70°and flexibility of 52.7%, the deformity improved from 58.4°preoperatively to 12.3°postoperatively (percent correction 78.9%). In 22 patients with a major curve >70°and flexibility of 25.6%, the deformity improved from 94.1°preoperatively to 30.1°postoperatively (percent correction 68.1%). In the cohort study, in the SMA group, the pre-operative major curve was 92.6±13.7°with a flexibility of 25.5± 7.3% was corrected to 29.4±5.7°demonstrating a 68.4% immediate postoperative correction. In the traditional group, the pre-operative major curve was 88.6±14.6°with a flexibility of 29.3±6.6% was corrected to 37.2±7.3°demonstrating a 57.8% immediate postoperative correction. There was a statistic difference between the SMA group and traditional group in correction rate of the major thoracic curve.3. For patients with major curve at thoracic spine, in SMA group, the average preoperative apical vertebral rotation of 16.2°spine was corrected to 7.5°, showing 50.4% correction, whereas rod derotation group, the correction was from 15.3°to 9.9°(34.8%). There was statistically significant difference rotational correction (p< 0.05). For patients with major curve at lumbar spine, in SMA group, the average preoperative apical vertebral rotation of 26.2°pine was corrected to 13.7°, showing 47.6% correction, whereas rod derotation group, the correction was from 25.4°to 14.5°(42.8%). There was no statistically significant difference rotational correction (p > 0.05).Conclusions.1. The shape memory alloy based scoliosis correction is a real 3D technique.2. The temporary use of a shape memory rod is a safe and effective method to correct scoliosis, and the temporary use of shape memory alloy rod may reduce the operative time, blood loss, and decrease the failure rate of pedicle screws, while improve the correction of the coronal plane compared to standard techniques;3. Shape memory alloy based scoliosis correction can improve the derotation effect at thoracic spine, and can not at lumbar spine.更多还原