Department of Spine Surgery, Beijing Jishuitan Hospital, No. 31, Xinjiekou East St, Xicheng District, Beijing, 100035, China.
BMC Musculoskelet Disord. 2023 Feb 1;24(1):88. doi: 10.1186/s12891-022-06041-x.
Short-term researches have studied the change of the center of rotation (COR) after the Bryan Cervical disc arthroplasty (CDA). But there is a lack of long-term studies focusing on the location of COR and its influence after surgery.
Clinical and radiographic materials of patients who received CDA were retrospectively reviewed. Written informed consents were obtained. Clinical outcome was accessed by Japanese Orthopaedic Association (JOA), Neck Disability Index (NDI), and Odom's scale. Radiographic evaluation underwent before surgery, at early (3 months) follow-up and final (minimal 10 years) follow-up. The ROM of the global cervical spine and index level, the functional spine unit (FSU) angle and C2-C7 angle were measured. COR was identified and its coordinates were calculated. The absolute change of COR-x and COR-y were compared in subgroup analysis.
Sixty patients were included, with an average age of 55.9 ± 8.1 years old. The mean duration of follow up was 135.1 ± 16.1 (120-155) months. JOA, NDI and Odom's scale showed significant improvements at 10 years after surgery. The COR of index level was located in the posterior superior half of the caudal vertebral body. Following the implant of Bryan Disc, the COR shifted forward and downward. During the 10-year follow-up, the location of COR remained stable. ROM at the index level decreased from 10.6 ± 4.0° preoperatively to 9.3 ± 4.0° at the early follow-up (p = 0.03). The ROM at the index level remained unchanged from early follow-up to the final follow-up (9.3 ± 4.0° vs 9.5 ± 5.2°, p = 0.80). In subgroup analysis, larger changes of both COR-x and COR-y were related with decreased ROM.
Our study illustrated that Bryan CDA could achieved favorable clinical and radiographic outcome over a minimal 10-year follow-up. The reduction of the flexion-extension ROM may be correlated with a more deviated postoperative COR. More attention should be paid to preoperative design and intraoperative technique to obtain a more native COR.
短期研究已经研究了 Bryan 颈椎间盘置换术（CDA）后旋转中心（COR）的变化。但缺乏长期研究来关注手术后 COR 的位置及其影响。
回顾性分析接受 CDA 的患者的临床和影像学资料。获得书面知情同意。临床结果通过日本矫形协会（JOA）、颈部残疾指数（NDI）和 Odom 量表进行评估。在术前、早期（3 个月）随访和最终（至少 10 年）随访时进行影像学评估。测量全颈椎的 ROM 和指数水平、功能脊柱单位（FSU）角和 C2-C7 角。确定 COR 并计算其坐标。在亚组分析中比较 COR-x 和 COR-y 的绝对变化。
共纳入 60 例患者，平均年龄 55.9±8.1 岁。平均随访时间为 135.1±16.1（120-155）个月。术后 10 年，JOA、NDI 和 Odom 量表均有显著改善。指数水平的 COR 位于下位椎体的后上半部分。Bryan Disc 植入后，COR 向前向下移位。在 10 年随访期间，COR 的位置保持稳定。指数水平的 ROM 从术前的 10.6±4.0°减少到早期随访时的 9.3±4.0°（p=0.03）。从早期随访到最终随访，指数水平的 ROM 保持不变（9.3±4.0°比 9.5±5.2°，p=0.80）。在亚组分析中，COR-x 和 COR-y 的较大变化与 ROM 的减少有关。
本研究表明，Bryan CDA 在至少 10 年的随访中可获得良好的临床和影像学结果。屈伸 ROM 的减少可能与术后 COR 更偏有关。应更加注意术前设计和术中技术，以获得更接近自然的 COR。
