改良3D打印导航模板辅助寰枢椎椎弓根螺钉置钉的准确性分析

Analysis on accuracy of advanced 3D printing navigation template in assisting the placement of atlanto-axial vertebral pedicle screw

中文关键词:  寰枢椎  改良导航模板  3D打印  偏差

英文关键词:Atlanto-axial vertebral body  Advanced navigation template  3D printing  Deviation

中文摘要:

  【摘要】 目的：探讨改良3D打印导航模板辅助寰枢椎椎弓根螺钉置钉的准确性。方法：选择我院2015年6月~12月期间行寰枢椎手术的患者17例，男11例，女6例；年龄25~56岁，平均43.3±8.7岁；寰枢椎骨折脱位13例，寰枢椎畸形4例。术前将患者的寰枢椎CT数据导入Mimics17.0软件，生成目标椎体的三维模型，使用逆向工程原理设计与其表面相吻合的反向模板及椎弓根螺钉最佳钉道并生成相应导向通道，标杆相对通道向内侧平移约10mm，将导向通道及标杆与模板拟合一体，设计形成带有导向通道和标杆的改良导航模板。将设计好的导板通过3D打印机打印出来。在3D模型上模拟置钉，体外试验确认方案可行后再将改良导航模板消毒、灭菌并应用于临床。术中将改良3D打印导板与寰枢椎紧密贴合。术者分别以电钻及手钻通过导向通道，以标杆为参照物及导向杆，通过导向通道钻探螺钉通道后取下导板，攻丝后顺钉道置入椎弓根螺钉。将术前规划钉道与术后螺钉配对拟合进行螺钉精确性分析，并以Kawaguchi等评价法判断螺钉位置的优劣等级。结果：手术时间106±11min，术中出血量为220±73ml。共置入68枚颈椎椎弓根螺钉，其中寰椎与枢椎各34枚。术前预设进钉点、内倾角及头倾角与术后相比差异均无统计学意义（P>0.05）。术后Kawaguchi等评价法显示：0级占97.06％（66/68），Ⅰ级占2.94％（2/68），有2枚螺钉穿破骨皮质，Ⅱ、Ⅲ级螺钉数为0。结论：通过改良3D打印导板辅助寰枢椎椎弓根置钉，可提高与术前预设最佳钉道的吻合度、精确匹配术前计划，可提高临床手术置钉的准确性，减少偏差。

英文摘要:

  【Abstract】 Objectives: To explore the accuracy of advanced 3D printing navigation template in assisting the placement of atlanto-axial vertebral pedicle screw. Methods: 17 patients who underwent pedicle screw placement of atlanto-axial vertebral were selected from our hospital between June 2015 and December 2016, including 11 males and 6 females, aging from 25 to 56 years(43.3±8.7 years). 13 patients had atlanto-axial vertebral fracture and dislocation while 4 cases had atlanto-axial vertebral deformity. Atlanto-axial CT data of patients were input into Mimics17.0 to generate a 3D model of the target vertebral body. The cylinder with the diameter of 3.5mm was used for simulation of screws in the computer-aided design software to make preliminary simulation of pedicle screw placement parallel to the direction of pedicle screw. The position relation between the screw channels and the screw channel was carefully adjusted to ensure the pedicle bone cortex was not broken through by the screw channel. The benchmark was moved parallelly about 10mm towards the inside relatively to the screw hole. The guide plate file was imported into the Forml+3D printer to print the atlanto-axial pedicle screw guide plate. The guide plate was disinfected with ethylene oxide and encapsulated for subsequent use. The surgical operations were simulated preoperatively in the previously 3D-printed model,the scheme was confirmed by in vitro test before the advanced navigation template disinfected, sterilized and applied to clinical. Advanced 3D printing template was closely adhered to the atlanto-axial vertebral body during operation. The surgeon drilled out the screw channel through the guiding channel by drill with pole as the reference, and the guiding plate was removed, and pedicle screw was placed along the screw channel. Results: The operation time was 106±11min and the intraoperative blood loss was 220±73ml. A total of 68 cervical pedicle root screws were placed, including 34 cases in atlas and 34 cases in axis. There were no statistically significant differences between preoperative and postoperative pre-designed nailing points, the inclination angle and head tilt angle(P>0.05). Postoperative Kawaguchi scale showed level 0 accounting in 97.06%(66/68), level Ⅰ in 2.94%(2/68), level Ⅱ and Ⅲ in 0, and two screws were broke through bone cortex. Conclusions: By using the advanced 3D printing navigation template auxiliary atlanto-axial vertebral pedicle nailing guide, alignment with the preoperative default best nail can be improved to exact match preoperative plan, the accuracy of clinical surgery nailing can be improved to reduce the deviation.