Department of Orthopedic Surgery, Beijing Chaoyang Hospital, Capital Medical University of China, Beijing, China.
Clin Spine Surg. 2021 Mar 1;34(2):E112-E120. doi: 10.1097/BSD.0000000000001059.
This was a retrospective observational study.
We aimed to characterize the feasibility of assessing the accuracy of cortical bone trajectory (CBT) screw placement in midline lumbar interbody fusion using a traditional pedicle screw insertion accuracy evaluation system based on computed tomography (CT).
Since Santoni and colleagues proposed CBT as an alternative approach for the treatment of lumbar degenerative disease, CBT has been biomechanically and clinically investigated in detail. The reported misplacement rate was 0%-12.5%. Therefore, these cortical screws may result in severe complications, such as nerve root, vascular, and spinal cord injuries. However, to the best of our knowledge, the accuracy of the current assessment system of cortical bone screw placement has not been described clearly.
Overall, 342 cortical screws of 69 consecutive patients with lumbar degenerative disease who underwent midline lumbar interbody fusion surgery in one surgeon's initial phase were examined retrospectively. A comprehensive and detailed pedicle screw accuracy classification and grading system was introduced in our study, including 5 types of misplacement: (1) medial and (2) lateral cortical bone perforation (MCP and LCP) of the corresponding pedicle, (3) anterior cortical bone perforation of the vertebral body, (4) endplate perforation, and (5) foraminal perforation (FP). The degree of interobserver and intraobserver agreement with regard to the screw positions based on CT were used as indicators of the reliability of the modified classification system. All patients were retrospectively assessed for screw placement-related complications throughout the entire treatment course to evaluate the relationship between the procedure adequacy and neurological symptoms.
The interobserver and intraobserver agreements were substantial-to-almost perfect (κ=0.78 and 0.88, respectively) in distinguishing the acceptable-placed pedicle screws from those with partial or complete cortical perforation. In the MCP and LCP-the most common types of misplacement-the interobserver agreement was substantial (κ=0.70 and 0.76, respectively), and the intraobserver agreement was almost perfect (κ=0.85 and 0.89, respectively). In total, there are 7 (2.05%) MCP and 65 (19.01%) LCP screws. The screw placement-related complication rate is significantly higher in the MCP and FP groups than that in the LCP group.
Our study demonstrated that using a pedicle screw classification and grading system based on CT to assess the accuracy of CBT screw placement is feasible and practical. MCP and FP screws are more likely to cause neurological deficits with statistical significance, especially grade 2 MCP. We recommend inexperienced surgeons choose a lateral trajectory rather than a medial one if they cannot ensure accurate screw insertion.
Level III.
这是一项回顾性观察研究。
我们旨在通过基于计算机断层扫描（CT）的传统椎弓根螺钉插入准确性评估系统，评估在中线腰椎椎间融合术中评估皮质骨轨迹（CBT）螺钉放置准确性的可行性。
自从 Santoni 及其同事提出 CBT 作为治疗腰椎退行性疾病的替代方法以来，CBT 已经在生物力学和临床方面进行了详细研究。报道的错位率为 0%-12.5%。因此，这些皮质螺钉可能导致严重并发症，如神经根、血管和脊髓损伤。然而，据我们所知，目前皮质骨螺钉放置评估系统的准确性尚未得到明确描述。
总体而言，我们回顾性地检查了 69 名连续接受中线腰椎椎间融合术的腰椎退行性疾病患者的 342 枚皮质螺钉。在我们的研究中，引入了一种全面而详细的椎弓根螺钉准确性分类和分级系统，包括 5 种类型的错位：（1）相应椎弓根的内侧和（2）外侧皮质骨穿孔（MCP 和 LCP），（3）椎体前皮质骨穿孔，（4）终板穿孔和（5）椎间孔穿孔（FP）。基于 CT 确定螺钉位置的观察者间和观察者内一致性程度被用作改良分类系统可靠性的指标。所有患者在整个治疗过程中均回顾性评估螺钉放置相关并发症，以评估手术充分性与神经症状之间的关系。
在区分可接受的置钉和部分或完全皮质穿孔的椎弓根螺钉时，观察者间和观察者内的一致性为中等至几乎完美（κ=0.78 和 0.88）。在最常见的 MCP 和 LCP 错位类型中，观察者间的一致性为中等（κ=0.70 和 0.76），而观察者内的一致性为几乎完美（κ=0.85 和 0.89）。总的来说，有 7 枚（2.05%）MCP 和 65 枚（19.01%）LCP 螺钉。MCP 和 FP 组的螺钉放置相关并发症发生率明显高于 LCP 组。
我们的研究表明，使用基于 CT 的椎弓根螺钉分类和分级系统评估 CBT 螺钉放置的准确性是可行且实用的。MCP 和 FP 螺钉更有可能导致具有统计学意义的神经功能缺损，尤其是 2 级 MCP。我们建议经验不足的外科医生如果不能确保准确插入螺钉，选择外侧轨迹而不是内侧轨迹。
III 级。
