3D打印及术前数字化设计辅助椎弓根置钉治疗寰枢椎不稳的临床疗效

Clinical efficacy of 3D printing and preoperative digital design assisted pedicle screw placement for atlantoaxial instability

背景:临床中寰枢椎椎弓根螺钉准确置入有一定难度。目前,辅助寰枢椎椎弓根钉置钉的方法众多,但大多存在设计、操作使用繁琐复杂等问题。目的:总结分析3D打印及术前数字化设计辅助椎弓根置钉治疗寰枢椎不稳的临床疗效。方法:本研究纳入2014年8至2017年12月使用术前数字化设计及3D打印技术辅助置钉治疗的14例寰枢椎不稳患者,男8例,女6例,年龄26～67岁,平均(47.3±13.8)岁。陈旧性骨折5例,齿状突畸形8例,类风湿性关节炎1例。术前将患者的寰枢椎CT数据导入Mimics17.0软件,生成三维模型,数字化设计椎弓根螺钉的最佳钉道并生成相应文件,测量记录进钉点的位置及钉道的内倾角、头倾角数据。通过3D打印机打印实物模型。在实物模型上模拟置钉。术中根据术前设计完成螺钉通道,攻丝后置入螺钉。术后行CT扫描比较手术前后内倾角、头倾角变化,并进行螺钉位置分级,评价螺钉准确性。随访确定患者恢复情况。结果:14例患者均顺利完成手术,手术时间110～200 min,平均(146±34)min;术中出血量150～300 ml,平均(213±45)ml;透视5～11次,平均(7.4±1.5)次;术后拔管前引流总量90～200ml,平均(140±34)ml。共置入56枚螺钉。螺钉准确性:0级占94.6%(53/56),Ⅰ级占5.4%(3/56),Ⅱ、Ⅲ级为0。手术前后螺钉内倾角和头倾角相比差异均无统计学意义(P>0.05)。随访8～36个月,平均(18.6±8.1)个月。无椎动脉、神经损伤及感染等出现。至末次随访均植骨融合,VAS评分从术前(3.9±1.1)分(3～6分)降至(0.9±0.6)分(0～2分),9例术前脊髓功能Frankel D级患者均恢复至E级。结论:通过3D打印及术前数字化设计辅助寰枢椎不稳治疗,方法简便,可充分了解局部情况,指导手术,提高置钉准确性。

Background： It is very difficult to accurately implant atlantoaxial pedicle screws. At present,there are many methods for assisting atlantoaxial pedicle screw placement, but most of them are complicated in design and operation. Objective： To summarize the clinical efficacy of 3D printing and preoperative digital design assisted pedicle screw placement for atlantoaxial instability. Methods： Fourteen patients with atlantoaxial instability who were treated with preoperative digital design and 3D printing technology assisted nailing from August 2014 to December 2017 were enrolled in this study. There were 8 males and 6 females with a mean age of（47.3±13.8） years（range, 26-67 years）. There were 5 cases of old fracture, 8 cases of odontoid deformity, and 1 case of rheumatoid arthritis. The patient＇s atlantoaxial CT data was imported into Mimics 17.0 software before surgery to generate a three-dimensional model. The optimal nail path of the pedicle screw was digitally designed and corresponding files were generated to measure the position of the entry point and the leaning angle of the nail. The physical model was printed with a 3D printer. The nailing was simulated in the physical model. During the operation, the screw channel was constructed based on the preoperative design, and the screw was placed after tapping. CT scans were performed after surgery to analyze the changes of the angles. Screw position was graded to evaluate the accuracy of the screws. Follow-up was regularly performed to determine the recovery of the patient. Results： All the 14 patients successfully completed the operation. The mean operation time was（146±34） min（range,110-200 min）. The intraoperative blood loss was（213±45） ml（range, 150-300 ml）. The average number of fluoroscopy was（7.4± 1.5） times（range,5-11 times）. The total amount of drainage before extubation was（140±34） ml（range, 90-200 ml）. A total of 56 screws were placed. Screw accuracy： level 0 was 94.6%（53/56）, level I was 5.4%（3/56）, and level Ⅱ and Ⅲ was 0. There was no significant difference in the angles of inclination of the screw or the head tilt angle before and after operation（P〈0.05）. The mean duration of follow-up was（18.6±8.1） months（range, 8-36 months）. No vertebral artery injury, nerve injury or infection appeared. Bone fusion was achieved at the last follow-up. VAS score dropped from 3.9±1.1（range,3-6） preoperatively to 0.9±0.6（range,0_2） at the last follow-up. Nine patients with preoperative spinal cord function Frankel D grade recovered to grade E. Conclusions： 3D printing and preoperative digital design assisted pedicle screw placement for atlantoaxial instability can fully understand the local situation, guide operation, and improve the accuracy of nail placement. It is a simple practical method in clinic.