Yamaguchi Satoshi, Park Brian J, Takeda Masaaki, Mitsuhara Takafumi, Shimizu Kiyoharu, Chen Pei-Fu, Woodroffe Royce W
Department of Neurosurgery, University of Iowa Hospitals and Clinics, Iowa City, United States.
Department of Neurosurgery, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima City, Hiroshima, Japan.
Surg Neurol Int. 2022 Mar 31;13:116. doi: 10.25259/SNI_198_2022. eCollection 2022.
The healing process after C1-C2 posterior screw fixation (C1-C2 PSF) for odontoid fractures is not well understood. Here, we evaluated such processes and identified factors potentially contributing to pseudoarthroses following fusions for Type II odontoid fractures.
Pre- and post-operative cervical radiographs and computed tomography (CT) images from 15 patients with preoperative Type II odontoid fractures who underwent C1-C2 PSF were retrospectively reviewed.
CT images identified three areas of bone fusion: The primary fracture site in the dens (9/15 patients, 60%), the atlanto-dental interspace (ADI) (10/15, 67%), and C1-C2 interlaminar space after onlay bone grafting (4/15, 27%). All patients showed bone fusion in at least one of three areas, while only one patient (6.7%) achieved bone fusion in all three areas. With these overall criteria, nine of 15 patients (60%) were considered fused, while six patients (40%) were determined to exhibit pseudoarthroses. Univariate analyzes showed that the preoperative C2-C7 SVA for the nonunion group was significantly larger versus the union group, and bone fusion at the level of the ADI was significantly more common in the nonunion versus the union group.
CT studies identified three anatomical areas where bone fusion likely occurs after C1-C2 PSF. Increased sagittal balance in the cervical spine may negatively impact the fusion of odontoid fractures. Further, bone fusion occurring at other sites, not the primary fracture location, through stress shielding may contribute to delayed or failed fusions.
对于齿状突骨折行C1-C2后路螺钉固定（C1-C2 PSF）后的愈合过程，目前尚未完全明确。在此，我们评估了此类过程，并确定了可能导致II型齿状突骨折融合后出现假关节的因素。
回顾性分析15例术前II型齿状突骨折并接受C1-C2 PSF治疗患者的术前和术后颈椎X线片及计算机断层扫描（CT）图像。
CT图像确定了三个骨融合区域：齿突的原发性骨折部位（9/15例患者，60%）、寰齿间隙（ADI）（10/15，67%）以及植骨后C1-C2椎板间隙（4/15，27%）。所有患者在三个区域中的至少一个区域显示骨融合，而只有1例患者（6.7%）在所有三个区域均实现骨融合。按照这些总体标准，15例患者中有9例（60%）被认为融合，而6例患者（40%）被判定为出现假关节。单因素分析显示，与融合组相比，骨不连组术前C2-C7矢状面垂直轴（SVA）显著更大，并且与融合组相比，骨不连组在ADI水平的骨融合明显更常见。
CT研究确定了C1-C2 PSF术后可能发生骨融合的三个解剖区域。颈椎矢状面平衡增加可能对齿状突骨折的融合产生负面影响。此外，通过应力遮挡在其他部位而非原发性骨折部位发生的骨融合可能导致融合延迟或失败。
