计算机辅助外科技术在寰枢椎损伤螺钉置入术中的应用

Application of computer-assisted surgical technology in screw implantation for atlantoaxial injuries

目的采用CT三维重建技术测量寰枢椎关节的解剖数据,评价寰枢椎损伤患者椎弓根螺钉置入术的可行性和准确性。方法 2007年7月至2014年3月41例患者中21例寰椎损伤,15例枢椎损伤,5例寰枢椎联合损伤。于螺钉内固定术前行拟固定椎体节段的椎弓根层面薄层CT（64排GE Light speed VCT）扫描,0.625 mm薄层重建后数据传输到GE ADW 4.3工作站,采用容积重建（VR）和多平面重建（MPR）技术生成三维重建图像,然后传送到PACS诊断工作站,采用内置功能软件测量寰椎后弓以及枢椎峡部的上下径、内外径、上倾角、内倾角及椎弓根长度等数据,评估椎弓根螺钉置入术的可行性,确定螺钉的直径和长度,置入时最佳进针点、方向、深度。结果41例患者椎弓根螺钉置入术均顺利完成,共置入152枚螺钉,均安全有效。手术时间80~160 min。术中出血量70~250 ml。无椎动脉、神经根及脊髓损伤。术后复查CT有3枚枢椎椎弓根螺钉突破椎弓根外侧壁进入椎动脉孔中,但无椎动脉损伤并发症。随访6个月~2年,经复查CT证实骨折愈合率及骨融合率均为100%。5例寰椎椎弓根最小高度〈5 mm,选择适当下移螺钉及选择直径3.0 mm螺钉置入,效果满意;2例枢椎椎弓根宽度〈5 mm,采用特制直径为3.0 mm螺钉,固定效果较好。结论通过术前CT三维重建测量寰枢椎椎弓根相关数据,制定个性化的置钉方案,可以提高椎弓根螺钉位置的准确性,减少寰枢椎损伤术后并发症的发生。

Objective To assess the feasibility and accuracy of pedicle screw implantation on the basis of anatomical data of atlantoaxial joint measured by CT three dimensional reconstruction technique in the patients with atlantoaxial injuries. Methods A total of 41 patients including 21 cases of atlas injury, 15 cases of axial injury and 5 cases of atlantoaxial injury were selected as observation objects. The thin slices CT scan （ using 64 multi-slice CT scanner） at the pedicle level of rele- vant vertebral segments of fixation to be done was performed before screw internal fixation. The data reconstructed by 0. 625 mm thin layer were transfered to GE ADW 4.3 workstation. The three dimensional reconstructed images were generated by volume reconstruction （VR） and muhiplanar reconstruction （MPR） techniques and then were transferred to PACS worksta- tions. The vertical and horizontal diameters, the up-dip and Inner-dip angles of atlas posterior arch and axial isthmus and the length of pedicle were measured with built-in function software to evaluate the feasibility of pedicle screw placement and define the diameter and length of screws and the optimal point, direction and depth of puncture. Results The pedicle screw implantation operations were all successfully completed in the 41 patients. A total of 152 screws were implanted ,and the in- ternal fixations were safe and effective. The operational times were 80 to 160 minutes. The volumes of intraoperative blood loss were 70 to 250 ml. No injuries of vertebral artery, nerve root and spinal cord occurred. The postoperative CT reexamine showed that 3 axis pedicle screws broke through the lateral wall of the pedicle and entered into the vertebral artery foramen, but no complications of vertebral artery injuries occurred. The follow-up period was 6 months to 2 years. CT reexamine con- firmed that the fracture healing rate and bone fusion rate were all 100%. In 5 patients with minimum height of atlas verte-bral pedicle less than 5 mm, the methods of appropriate down-displacing screws and implanting the screws of 3mm diameter were selected and the satisfactory effects were acquired. In 2 patients with the width of axis vertebral pedicle less than 5ram,better fixation effects were acquired by using special screws of 3.0m diameter. Conclusions Establishing individual implanting screw regime on the basis of relevant data of atlantoaxial vertebral pedicle measured by CT three dimensional re- construction technique can increase accuracy of location of vertebral pedicle screw and reduce the occurrence of complica- tions ＇after operations of atlanto-axial injuries.