Chen Chao-Hsuan, Chen Der-Cherng, Huang Hsiang-Ming, Chuang Hao-Yu, Hsu Wei-Lin, Cho Der-Yang, Lee Han-Chung, Bau Da-Tian
Department of Neurosurgery, China Medical University Hospital, China Medical University, Taichung.
Department of Neurosurgery, China Medical University Hsinchu Hospital, Hsinchu.
Medicine (Baltimore). 2020 Oct 2;99(40):e22186. doi: 10.1097/MD.0000000000022186.
This study aimed to verify the relationship between the number of fusion level and the risk of screw loosening by using cortical bone trajectory (CBT) screws in patients with lumbar degenerative disease.We retrospectively reviewed the serial plain radiograph images of lumbar degenerative disease patients who had undergone posterior fixation and fusion surgery with CBT from 2014. All included patients should have been followed-up with computed tomography scan or plain radiograph for at least 6 months after operation. We individually evaluated the prevalence of screw loosening according to each vertebral level. We also determined whether the number of screw fixation affected the prevalence of screw loosening and whether S1 fixation increased the risk of screw loosening.The screw-loosening rates were high at the S1 level. Moreover, although fixation involved to S1, the loosening rates evidently increased (Fisher exact test, P = .002). The screw-loosening rate was 6.56% in 2 level fusion. However, it increased with the number of fusion levels (3 level: 25.00%, 4 level: 51.16%, and 5 level: 62.50%). To investigate if the number of fusion level affected the S1 screw loosening, we classified the cohort of patients into either involving S1 (S1+ group) or not (S1- group) according to different fusion levels (). The screw loosening between 2 group in 2 (5.56% vs 6.98%) and 3 fusion level (26.32% vs 22.73%) did not exhibit any significant difference. Interestingly, significantly high screw loosening was found in 4 fusion level (60.00% vs 15.38%), indicating that the higher fusion level (4 level) can directly increase the risk of S1 screw loosening.Our data confirmed that the screw-loosening rate increases rate when long segment CBT fixation involves to S1. Therefore, in case of long-segment fixation by using CBT screw, surgeons should be aware of the fusion level of S1.
本研究旨在通过对腰椎退行性疾病患者使用皮质骨轨迹（CBT）螺钉，验证融合节段数量与螺钉松动风险之间的关系。我们回顾性分析了2014年以来接受CBT后路固定融合手术的腰椎退行性疾病患者的系列X线平片图像。所有纳入患者术后均应接受计算机断层扫描或X线平片随访至少6个月。我们根据每个椎体节段单独评估螺钉松动的发生率。我们还确定了螺钉固定数量是否影响螺钉松动的发生率，以及S1节段固定是否会增加螺钉松动的风险。S1节段的螺钉松动率较高。此外，尽管固定涉及S1节段，但松动率明显增加（Fisher精确检验，P = 0.002）。2节段融合时螺钉松动率为6.56%。然而，其随融合节段数量增加而升高（3节段：25.00%，4节段：51.16%，5节段：62.50%）。为研究融合节段数量是否影响S1螺钉松动，我们根据不同融合节段将患者队列分为涉及S1节段组（S1+组）和不涉及S1节段组（S1-组）。2节段融合（5.56%对6.98%）和3节段融合（26.32%对22.73%）时两组间的螺钉松动情况无显著差异。有趣的是，4节段融合时发现螺钉松动显著增加（60.00%对15.38%），表明较高的融合节段（4节段）可直接增加S1螺钉松动的风险。我们的数据证实，当长节段CBT固定涉及S1节段时，螺钉松动率会增加。因此，在使用CBT螺钉进行长节段固定时，外科医生应注意S1节段的融合情况。
