Patton Andrew G, Morris Randal P, Kuo Yong-Fang, Lindsey Ronald W
From the Departments of *Orthopaedic Surgery and Rehabilitation and †Internal Medicine, Division of Geriatric Medicine, The University of Texas Medical Branch, Galveston, TX.
Spine (Phila Pa 1976). 2015 Apr 1;40(7):E404-10. doi: 10.1097/BRS.0000000000000786.
Randomized laboratory cadaver study.
The objective of this study was to determine the accuracy of anterior transpedicular screw placement in the cervical spine using conventional fluoroscopy versus computer-assisted navigation.
Traditionally, global cervical instability has required anterior and posterior fixation due to the superior biomechanical stability of circumferential constructs. Anterior transpedicular screws (ATPS) have recently been advocated as a single surgical approach. Current clinical publications report using fluoroscopic guidance for screw placement. Computer-assisted navigation (CAN) systems have demonstrated enhanced accuracy of pedicle screw placement at all spine levels but have not been assessed for ATPS.
The anterior vertebrae of 9 fresh frozen cadaver cervical spines were exposed, preserving the lateral and posterior soft tissue envelope. Nine practicing spine surgeons placed 2.0-mm titanium anterior transpecidular Kirschner wires into the C3-T1 pedicles bilaterally using fluoroscopy or CAN guidance. Specimens were imaged by computed tomography and virtual screws were overlaid on the K-wires. Targeting accuracy was compared between the 2 techniques in all planes using a 5-level grading scale.
The percentage of acceptable screw placements for fluoroscopy and CAN was 42.6% and 66.7%, respectively (P = 0.012). Catastrophic screw placement (grade 3 or 4) was 33.3% for fluoroscopy and 16.7% for CAN. In the multivariable model, the accuracy rate was 67% lower for fluoroscopy than for CAN after controlling for other factors (odds ratio: 0.33, 95% confidence interval: 0.14-0.79).
The accuracy of CAN-guided placement of K-wires for ATPS was superior to placement under fluoroscopic guidance, demonstrating statistically more acceptable screw placements and significantly less catastrophic virtual screws. However, malposition was still high, with potential for vertebral artery and neurological injury in a clinical setting. Further advancement in current ATPS techniques is warranted prior to widespread implementation in a patient setting.
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随机实验室尸体研究。
本研究的目的是确定使用传统荧光透视法与计算机辅助导航在颈椎中进行经椎弓根前路螺钉置入的准确性。
传统上，由于环形结构具有更好的生物力学稳定性，寰枢椎不稳需要前后路固定。最近，经椎弓根前路螺钉（ATPS）被提倡作为一种单一的手术方法。目前的临床出版物报道使用荧光透视引导进行螺钉置入。计算机辅助导航（CAN）系统已证明在所有脊柱节段椎弓根螺钉置入的准确性有所提高，但尚未对经椎弓根前路螺钉进行评估。
暴露9具新鲜冷冻尸体颈椎的椎体前部，保留外侧和后部软组织包膜。9名脊柱外科医生使用荧光透视或计算机辅助导航引导，在双侧C3-T1椎弓根内置入2.0毫米钛制经椎弓根前路克氏针。通过计算机断层扫描对标本进行成像，并将虚拟螺钉叠加在克氏针上。使用五级分级量表在所有平面上比较两种技术的靶向准确性。
荧光透视法和计算机辅助导航法可接受的螺钉置入百分比分别为42.6%和66.7%（P = 0.012）。荧光透视法灾难性螺钉置入（3级或4级）为33.3%，计算机辅助导航法为16.7%。在多变量模型中，在控制其他因素后，荧光透视法的准确率比计算机辅助导航法低67%（优势比：0.33，95%置信区间：0.14-0.79）。
计算机辅助导航引导下经椎弓根前路螺钉置入克氏针的准确性优于荧光透视引导下的置入，显示出统计学上更可接受的螺钉置入和显著更少的灾难性虚拟螺钉。然而，位置不当的情况仍然很高，在临床环境中存在椎动脉和神经损伤的可能性。在患者中广泛应用之前，当前经椎弓根前路螺钉技术有必要进一步改进。
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