PURPOSE Cadaveric studies have discouraged the use of cervical pedicle screws (CPS) with high misplacement rates. However, the clinical results show minimal screw-related complications and have highlighted the advantages of using CPS. We introduce "acceptable errors classification" in the placement of cervical pedicle screws to bridge the gap between the high radiological perforation rates and low clinical complications. METHODS Ninety-nine patients with average age of 49 years were operated between December 2011 and June 2017 using CPS. Sixty-one patients had trauma, 33 had CSM, 3 had tumors and 2 patients had fracture with ankylosing spondylitis. The screws were inserted using the medial cortical pedicle screw technique. Axial and sagittal CT reconstructed images along the axis of the inserted screws were evaluated for screw placements both in the medio-lateral and supero-inferior directions. RESULTS A total of 577 pedicle screw placements (C3 to C7) were assessed in 99 patients using the conventional grading of screw perforations and acceptable errors classification in both medio-lateral and supero-inferior directions. There were 25.64% (148/577) screw perforations and 74.35% (429/577) screw placements within the pedicle using the conventional perforation grading system. The same set of screws, assessed using the "Acceptable errors classification", showed 529 screws (91.68%) having acceptable placements and 48 screws (8.31%) having unacceptable placements. CONCLUSION The acceptable errors classification in placement of CPS seems to bridge the gap between the high radiological perforation rates and the low clinical complications. The present study reinforces studies reporting minimal clinical complications with high rates of screw misplacements. These slides can be retrieved under Electronic Supplementary Material.

中文翻译：

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评估577个颈椎椎弓根螺钉放置的可接受误差。

目的尸体研究不鼓励使用错位率高的颈椎椎弓根螺钉（CPS）。但是，临床结果显示，与螺钉相关的并发症最少，并且突出了使用CPS的优势。我们在颈椎椎弓根螺钉的放置中引入“可接受的错误分类”，以弥合高放射率和低临床并发症之间的差距。方法2011年12月至2017年6月之间使用CPS手术的平均年龄为49岁的99例患者。强直性脊柱炎患者61例，创伤CSM 33例，肿瘤3例，骨折2例。使用内侧皮质椎弓根螺钉技术插入螺钉。沿插入的螺钉的轴线进行轴向和矢状CT重建图像，以评估其在中外侧和上下方向上的螺钉位置。结果使用常规的螺钉穿孔分级和在中上，下下方的可接受误差分类，对99例患者进行了577个椎弓根螺钉置入（C3至C7）的评估。使用常规的穿孔分级系统，椎弓根内有25.64％（148/577）的螺钉穿孔和74.35％（429/577）的螺钉位置。使用“可接受的错误分类”评估的同一组螺钉显示529螺钉（91.68％）的位置可接受，而48颗螺钉（8.31％）的位置不可接受。结论可接受的CPS放置错误分类似乎弥合了高放射率和低临床并发症之间的差距。本研究加强了研究，报告了最小的临床并发症以及高螺钉错位率。这些幻灯片可以在电子补充材料下找到。