数字化“定点-定向”双导航模板辅助椎弓根螺钉置钉治疗寰枢椎不稳

Digital “pointing-drilling” double navigation template assisted pedicle screw placement for treatment of atlantoaxial instability

目的评价数字化"定点-定向"双导航模板辅助椎弓根螺钉置钉治疗寰枢椎不稳的临床效果。方法回顾性分析2013年9月—2016年12月收治的24例采用数字化"定点-定向"双导航模板辅助行颈椎后路椎弓根螺钉置钉的寰枢椎不稳患者的临床资料。术前CT扫描获取数据经Mimics 10.0软件三维重建后进行寰枢椎后路椎弓根螺钉置钉理想钉道的计算机辅助规划,并根据寰枢椎后方骨性结构表面数据设计个性化"定点-定向"双导航模板。在3D打印机上制作"定点-定向"双导航模板,高温消毒后应用于临床手术辅助置钉。术后根据颈椎X线和CT检查结果评价椎弓根螺钉的位置,并观察植骨融合情况及颈椎稳定性。采用颈部和/或枕骨下疼痛视觉模拟量表(VAS)评分评估患者的临床疗效。结果应用数字化双导航模板为24例患者置入椎弓根螺钉,22例行寰枢椎后路椎弓根螺钉固定,2例行寰枢椎后路椎弓根螺钉并椎板螺钉固定。共置入寰椎椎弓根螺钉48枚,枢椎椎弓根螺钉46枚,枢椎椎板螺钉2枚。术后CT检查示所有螺钉均未穿破钉道骨皮质。所有患者随访>6个月,大部分患者颈部疼痛明显缓解,VAS评分由术前(7.78±1.12)分降至术后(2.48±0.55)分,差异有统计学意义(P<0.05)。术前肌力下降者术后均不同程度恢复。所有患者均未发生神经、血管损伤等置钉相关并发症。结论数字化"定点-定向"双导航模板不仅能够提高手术置钉的准确性和安全性,还能针对不同类型的寰枢椎不稳提供更合理的置钉方式。

Objective To evaluate the clinical application of digital“pointing-drilling”double navigation template assisted pedicle screw placement for atlantoaxial instability.Methods From September 2013 to December 2016,the clinical data of 24 patients with atlantoaxial instability treated with posterior cervical vertebral pedicle screw fixation assisted by digital“pointingdrilling”double navigation template were collected and analyzed in this restrospective study.All the patients had undergone CT scan before operation.After the original data was imported into Mimics10.0 software,a three-dimensional model was reconstructed.The best trajectory of posterior atlantoaxial pedicle screw fixation was designed by a base plate which was a patientspecific complementary template for the posterior atlantoaxial corresponding anatomical surface,and then“pointing-drilling”guide template was materialized in rapid prototyping machine and used intra-operatively to assist screw instrumentation after high temperature sterilization.Position of the screws was determined through cervical roentgenograph and CT scan after operation,and bone fusion rate was evaluated.The neck pain visual analogue scale(VAS)score was used to evaluate clinical efficacy.Results All 24 patients underwent screw fixation were assisted by“pointing-drilling”double navigation template,consisting of 22 patients underwent posterior atlantoaxial pedicle screw fixation and the other 2 underwent posterior atlantoaxial pedicle screw combined with vertebral screw fixation.A total of 48 atlas pedicle screws were placed,and 46 axis pedicle screws combined with 2 axis vertebral screws.Postoperative CT examination showed that all screws did not wear through the trajectory bone cortex.All the patients were followed up>6 months.In most patients,the neck pain was significantly relieved.The VAS score reduced from(7.78±1.12)to(2.48±0.55),and the difference was statistically significant(P<0.05).Postoperative muscle strength was significantly improved.No complications,such as nerve or vascular injury,were found in all the patients.Conclusion Digital“pointing-drilling”double navigation template can not only improve the accuracy and safety of atlantoaxial pedicle screw placement,but also provide a more reasonable way of placing screws for different types of atlantoaxial instability.