Oh Kyu Won, Lee Jae Hyup, Lee Ji-Ho, Lee Do-Yoon, Shim Hee Jong
*Department of Orthopedic Surgery, SMG-SNU Boramae Medical Center, College of Medicine and Institute of Medical and Biological Engineering, Medical Research Center, Seoul National University †Department of Orthopedic Surgery, College of Medicine Seoul National University, Seoul, Korea.
Clin Spine Surg. 2017 Jul;30(6):E683-E689. doi: 10.1097/BSD.0000000000000315.
A retrospective review of prospectively collected radiographic and clinical data.
This study aims to investigate the relationship between cage subsidence and bone mineral density (BMD), and to reveal the clinical implications of cage subsidence.
Posterior lumbar interbody fusion (PLIF) has become one of the standard treatment modality for lumbar degenerative disease. However, cage subsidence might result in recurrent foraminal stenosis and deteriorate the clinical results. Furthermore, numbers of osteoporosis patients who underwent PLIF are increasing. Therefore, the information on the correlations between cage subsidence, BMD, and clinical results will be of great significance.
A total 139 segments was included in this retrospective study. We examined functional rating index (Visual Analogue Scale for pain, Oswestry Disability Index, Short Form-36 score) preoperatively, and investigated their changes after postoperative 1 year. Correlation between cage subsidence and clinical scores was investigated. Plain anteroposterior and lateral radiograph were taken preoperatively and postoperatively and during follow-up. Preoperative BMD and subsidence measured by postoperative 1 year 3-dimensional computed tomography were achieved and their correlation was assessed.
All postoperative clinical scores improved significantly compared with preoperative ones (pain Visual Analogue Scale: 7.34-2.89, Oswestry Disability Index: 25.34-15.86, Short Form-36: 26.45-16.46, all P<0.001). BMD showed significant weak correlation with subsidence (r=-0.285, P<0.001). Severe osteoporotic segments (T score <-3.0) had more risk to develop severe subsidence (>3 mm) compared with the segments in which T score were higher than -3.0 (P=0.012), and its odds ratio was 8.44. Subsidence had no significant correlation with all clinical scores.
This study revealed that cage subsidence is relevant to BMD. However, it was demonstrated that subsidence is not related to the clinical deterioration. Therefore, PLIF procedure which is conducted carefully can be a good surgical option to treat lumbar degenerative disease for osteoporotic patients.
对前瞻性收集的影像学和临床数据进行回顾性分析。
本研究旨在探讨椎间融合器下沉与骨密度（BMD）之间的关系，并揭示椎间融合器下沉的临床意义。
后路腰椎椎间融合术（PLIF）已成为腰椎退行性疾病的标准治疗方式之一。然而，椎间融合器下沉可能导致椎间孔狭窄复发并使临床疗效恶化。此外，接受PLIF手术的骨质疏松患者数量正在增加。因此，关于椎间融合器下沉、骨密度和临床疗效之间相关性的信息具有重要意义。
本回顾性研究共纳入139个节段。我们术前检查了功能评分指标（疼痛视觉模拟量表、Oswestry功能障碍指数、简明健康状况调查量表评分），并研究了术后1年这些指标的变化。研究了椎间融合器下沉与临床评分之间的相关性。术前、术后及随访期间拍摄了前后位和侧位X线平片。获取术前骨密度和术后1年三维计算机断层扫描测量的下沉情况，并评估它们之间的相关性。
与术前相比，所有术后临床评分均有显著改善（疼痛视觉模拟量表：7.34 - 2.89，Oswestry功能障碍指数：25.34 - 15.86，简明健康状况调查量表：26.45 - 16.46，均P < 0.001）。骨密度与下沉呈显著弱相关（r = -0.285，P < 0.001）。与T评分高于 -3.0的节段相比，严重骨质疏松节段（T评分 < -3.0）发生严重下沉（> 3 mm）的风险更高（P = 0.012），其比值比为8.44。下沉与所有临床评分均无显著相关性。
本研究表明椎间融合器下沉与骨密度相关。然而，研究表明下沉与临床恶化无关。因此，对于骨质疏松患者，谨慎进行的PLIF手术可以是治疗腰椎退行性疾病的良好手术选择。
