OBJECTIVE The performance of cervical disc arthroplasty (CDA) in the spine with malalignment was unclear. The purpose of the study was to report the clinical and radiological outcomes of single-level CDA in the patients with preoperative reversible kyphosis (RK) and compare these results with a matched cohort of preoperative lordosis. PATIENTS AND METHODS From 2014 to 2018, 36 patients with preoperative RK were matched with 229 patients with preoperative lordosis. The Japanese Orthopedic Association score, Neck Disability Index, Visual Analog Scale were used to evaluate clinical outcomes. Radiological evaluations included range of motion (ROM), C2-7 Cobb angle, shell angle (SA) at surgical level, functional spinal unit (FSU) angle and heterotopic ossification (HO). RESULTS The mean follow-up was 40.1 months. Both groups achieved significant improvements in clinical outcomes without significant intergroup differences. Before surgery, lordosis group had significantly greater C2-7 angle (9.5° vs -8.4°), SA (1.6° vs -3.7°), and FSU (2.9° vs -3.7°). After surgery, RK group experienced significant improvements in C2-7 angle and SA compared with preoperative data. In lordosis group, C2-7 angle, SA, and FSU were maintained. At the last follow-up, the intergroup difference of C2-7 angle, SA, and FSU remained significant. ROMs were preserved in both groups. The ROM of RK group was slightly lower than that of lordosis group but failing to reach a significance. Eleven patients in lordosis group and 21 patients in RK group developed HO (P = 0.127). There was a significant greater incidence of high-grade HO (grade Ⅲ, Ⅳ) in RK group (33.3 % vs 11.1 %, P = 0.034). CONCLUSION Both groups achieved satisfactory and comparable clinical outcomes after CDA. Despite the remarkable improvements compared with preoperative values, the cervical alignment of RK group was still significantly inferior to that of lordosis group. More HO formation occurred in RK group. Based on these results, we did not recommend CDA to the patients with preoperative RK.

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单节段颈椎间盘置换术治疗可逆性脊柱后凸患者的临床和放射学结果：匹配队列研究

目的 颈椎间盘置换术 (CDA) 在脊柱排列不齐的情况下的表现尚不清楚。该研究的目的是报告单节段 CDA 在术前可逆性脊柱后凸 (RK) 患者中的临床和放射学结果，并将这些结果与术前前凸的匹配队列进行比较。患者与方法 2014-2018年，36例术前RK患者与229例术前脊柱前凸患者配对。日本骨科协会评分、颈部残疾指数、视觉模拟量表用于评估临床结果。放射学评估包括运动范围 (ROM)、C2-7 Cobb 角、手术水平的壳角 (SA)、功能性脊柱单元 (FSU) 角和异位骨化 (HO)。结果 平均随访时间为 40.1 个月。两组均在临床结果方面取得了显着改善，但没有显着的组间差异。术前，脊柱前凸组的 C2-7 角（9.5° vs -8.4°）、SA（1.6° vs -3.7°）和 FSU（2.9° vs -3.7°）明显更大。手术后，与术前数据相比，RK 组的 C2-7 角和 SA 有显着改善。脊柱前凸组保持C2-7角、SA和FSU。在最后一次随访时，C2-7 角、SA 和 FSU 的组间差异仍然显着。两组均保留 ROM。RK组的ROM略低于前凸组但未达到显着性。前凸组11例患者和RK组21例患者发生HO（P=0.127）。RK组高级别HO（Ⅲ、Ⅳ级）发生率显着升高（33.3 % vs 11.1 %，P = 0.034）。结论 两组在 CDA 后均取得了令人满意且具有可比性的临床结果。尽管与术前相比有显着改善，但 RK 组的颈椎线度仍显着低于前凸组。RK 组发生更多的 H2O 形成。基于这些结果，我们不向术前 RK 患者推荐 CDA。