1Department of Orthopaedic Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong Province, China.
2Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania.
J Neurosurg Spine. 2023 Jun 9;39(3):320-328. doi: 10.3171/2023.4.SPINE23209. Print 2023 Sep 1.
Multiple rods are utilized in adult spinal deformity (ASD) surgery to increase construct stiffness. However, the impact of multiple rods on proximal junctional kyphosis (PJK) is not well established. This study aimed to investigate the impact of multiple rods on PJK incidence in ASD patients.
ASD patients from a prospective multicenter database with a minimum follow-up of 1 year were retrospectively reviewed. Clinical and radiographic data were collected preoperatively, at 6 weeks postoperatively, at 6 months postoperatively, at 1 year postoperatively, and at every subsequent year postoperatively. PJK was defined as a kyphotic increase of > 10° in the Cobb angle from the upper instrumented vertebra (UIV) to UIV+2 as compared with preoperative values. Demographic data, radiographic parameters, and PJK incidence were compared between the multirod and dual-rod patient cohorts. PJK-free survival analysis was performed using Cox regression to control for demographic characteristics, comorbidities, level of fusion, and radiographic parameters.
Overall, 307/1300 (23.62%) cases utilized multiple rods. Cases with multiple rods were more likely to be revisions (68.4% vs 46.5%, p < 0.001), to be posterior only (80.7% vs 61.5%, p < 0.001), involve more levels of fusion (mean 11.73 vs 10.60, p < 0.001), and include 3-column osteotomy (42.9% vs 17.1%, p < 0.001). Patients with multiple rods also had greater preoperative pelvic retroversion (mean pelvic tilt 27.95° vs 23.58°, p < 0.001), greater thoracolumbar junction kyphosis (-15.9° vs -11.9°, p = 0.001), and more severe sagittal malalignment (C7-S1 sagittal vertical axis 99.76 mm vs 62.23 mm, p < 0.001), all of which corrected postoperatively. Patients with multiple rods had similar incidence rates of PJK (58.6% vs 58.1%) and revision surgery (13.0% vs 17.7%). The PJK-free survival analysis demonstrated equivalent PJK-free survival durations among the patients with multiple rods (HR 0.889, 95% CI 0.745-1.062, p = 0.195) after controlling for demographic and radiographic parameters. Further stratification based on implant metal type demonstrated noninferior PJK incidence rates with multiple rods in the titanium (57.1% vs 54.6%, p = 0.858), cobalt chrome (60.5% vs 58.7%, p = 0.646), and stainless steel (20% vs 63.7%, p = 0.008) cohorts.
Multirod constructs for ASD are most frequently utilized in revision, long-level reconstructions with 3-column osteotomy. The use of multiple rods in ASD surgery does not result in an increased incidence of PJK and is not affected by rod metal type.
在成人脊柱畸形（ASD）手术中使用多根棒来增加结构的刚性。然而，多根棒对近端交界性后凸（PJK）的影响尚未得到很好的确定。本研究旨在探讨多根棒对 ASD 患者 PJK 发生率的影响。
回顾性分析了前瞻性多中心数据库中至少随访 1 年的 ASD 患者。收集术前、术后 6 周、术后 6 个月、术后 1 年和之后每年的临床和影像学数据。PJK 定义为与术前相比，UIV 到 UIV+2 的 Cobb 角增加> 10°。比较多棒和双棒患者队列之间的人口统计学数据、影像学参数和 PJK 发生率。使用 Cox 回归进行 PJK 无进展生存分析，以控制人口统计学特征、合并症、融合水平和影像学参数。
总体而言，307/1300（23.62%）例使用了多根棒。使用多根棒的病例更有可能是翻修病例（68.4%比 46.5%，p < 0.001），更有可能是后路手术（80.7%比 61.5%，p < 0.001），涉及更多的融合节段（平均 11.73 比 10.60，p < 0.001），并包括 3 柱截骨术（42.9%比 17.1%，p < 0.001）。使用多根棒的患者术前骨盆后倾也更大（平均骨盆倾斜度 27.95°比 23.58°，p < 0.001），胸腰椎交界处后凸更严重（-15.9°比-11.9°，p = 0.001），矢状面畸形更严重（C7-S1 矢状垂直轴 99.76 毫米比 62.23 毫米，p < 0.001），所有这些都在术后得到了纠正。使用多根棒的患者 PJK 发生率（58.6%比 58.1%）和翻修手术率（13.0%比 17.7%）相似。在控制人口统计学和影像学参数后，PJK 无进展生存分析显示多根棒患者的 PJK 无进展生存时间相当（HR 0.889，95%CI 0.745-1.062，p = 0.195）。基于植入物金属类型的进一步分层表明，多根棒在钛（57.1%比 54.6%，p = 0.858）、钴铬（60.5%比 58.7%，p = 0.646）和不锈钢（20%比 63.7%，p = 0.008）队列中 PJK 发生率无差异。
在 ASD 手术中，多根棒结构最常用于翻修和长节段重建伴 3 柱截骨术。在 ASD 手术中使用多根棒不会增加 PJK 的发生率，也不受棒金属类型的影响。
