Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA.
Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, USA.
World Neurosurg. 2023 Feb;170:e700-e711. doi: 10.1016/j.wneu.2022.11.109. Epub 2022 Nov 26.
The purpose this study was to precisely characterize patterns of allograft subsidence following anterior cervical discectomy and fusion (ACDF) utilizing computed tomography scans, determine risk factors for cervical allograft subsidence, and investigate the impact of subsidence on pseudarthrosis rates.
We performed a retrospective review of patients undergoing 1-to 3-level ACDF utilizing allograft interbodies with anterior plating between 2011 and 2019. Subsidence measurements were performed by 2 independent reviewers on computed tomography scans obtained 6 months postoperatively. Subsidence was then classified as mild if subsidence into the inferior and superior endplates were both ≤2 mm, moderate if the worst subsidence into the inferior- or superior endplate was between 2 and 4 mm, or severe if the worst subsidence into the inferior- or superior endplate was ≥4 mm. Multivariate analysis was performed to identify risk factors for the development of subsidence.
We identified 98 patients (152 levels) for inclusion. A total of 73 levels demonstrated mild subsidence (≤2 mm), 61 demonstrated moderate subsidence (2-4 mm), and 18 demonstrated severe subsidence (≥4 mm). On multivariate analysis, risk factors for severe subsidence included excessive vertebral endplate resection and lower screw tip to vertebral body height ratio. Severe subsidence was associated with an increased rate of pseudarthrosis (94.1% vs. 13.6%) without an associated increase in reoperation rate.
Following ACDF with allograft interbodies, 50% of interbodies will subside >2 mm and 10% of interbodies will subside >4 mm. Risk factors for severe subsidence should be mitigated to decrease the risk of pseudarthrosis.
本研究旨在通过计算机断层扫描精确描述颈椎前路融合术（ACDF）后移植物沉降的模式，确定移植物沉降的危险因素，并探讨沉降对假关节形成率的影响。
我们对 2011 年至 2019 年间接受 1-3 个节段 ACDF 且使用异体椎间融合器和前路钢板的患者进行了回顾性研究。术后 6 个月通过计算机断层扫描对沉降进行测量。沉降分为轻度（下、上终板沉降均≤2mm）、中度（下或上终板沉降最差处为 2-4mm）和重度（下或上终板沉降最差处≥4mm）。采用多变量分析确定沉降的危险因素。
共纳入 98 例患者（152 个节段）。73 个节段表现为轻度沉降（≤2mm），61 个节段表现为中度沉降（2-4mm），18 个节段表现为重度沉降（≥4mm）。多变量分析显示，严重沉降的危险因素包括过度切除椎体终板和较低的螺钉尖端与椎体高度比。严重沉降与假关节形成率增高相关（94.1%比 13.6%），但与再手术率增加无关。
在 ACDF 中使用异体椎间融合器后，50%的椎间体会沉降>2mm，10%的椎间体会沉降>4mm。应减轻严重沉降的危险因素，以降低假关节形成的风险。
