The authors¹ discuss the relationship between cervical sagittal balance parameters, namely, T1 slope, and range of motion (ROM) following cervical disc arthroplasty (CDA). They conclude that maintenance or improvement of cervical lordosis following CDA, especially in patients with good preoperative lordosis (T1 slope > 28°), may lead to better postoperative ROM. Since maintenance of motion is integral to the success of any arthroplasty device, factors contributing to better ROM following CDA are important to recognize. The cervical spine allows for the largest ROM in the spine, and an emerging body of evidence suggests that cervical sagittal balance has important clinical ramifications in terms of patient functional status and may play a role in adjacent segment pathology.^2-4 Global cervical sagittal imbalance, ie, kyphosis, is widely recognized as a contraindication for CDA, but the question remains: what degree of focal kyphosis is acceptable for arthroplasty patients and what are the ramifications of performing CDA on these patients? Although continued study is required to make definitive recommendations regarding the exact role of pre- and postoperative lordosis in patients undergoing CDA, the authors¹ are commended for attempting to identify factors that may predispose to improved outcomes following cervical arthroplasty.

中文翻译：

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评论：T1 斜率对颈椎间盘置换术后脊柱参数的影响。

作者^{图 1}讨论了颈椎椎间盘置换术 (CDA) 后颈椎矢状面平衡参数，即 T1 斜率和运动范围 (ROM) 之间的关系。他们得出的结论是，CDA 后颈椎前凸的维持或改善，尤其是术前前凸良好（T1 斜率 > 28°）的患者，可能会导致更好的术后 ROM。由于运动的维持对于任何关节成形术设备的成功都是不可或缺的，因此重要的是要认识到有助于遵循 CDA 获得更好 ROM 的因素。颈椎允许脊柱中最大的 ROM，并且新出现的证据表明，颈椎矢状面平衡在患者功能状态方面具有重要的临床影响，并且可能在相邻节段病理中发挥作用。^{2-4 整体}颈椎矢状面不平衡，即后凸畸形，被广泛认为是 CDA 的禁忌症，但问题仍然存在：关节置换术患者可接受何种程度的局灶性后凸畸形，对这些患者进行 CDA 的后果是什么？尽管需要继续研究以对接受 CDA 的患者术前和术后脊柱前凸的确切作用提出明确的建议，但作者¹因试图确定可能有助于改善颈椎关节置换术后结果的因素而受到赞扬。