Department of Orthopaedic Surgery, School of Medicine, Gifu University, 1-1 Yanagido, Gifu city, Gifu, 501-1194, Japan.
Department of Radiology, School of Medicine, Gifu University, Gifu, Japan.
BMC Musculoskelet Disord. 2021 Nov 29;22(1):995. doi: 10.1186/s12891-021-04874-6.
Ectopic gas in the graft is occasionally encountered upon follow-up computed tomography (CT) after anterior cervical corpectomy and fusion (ACCF). However, most cases lack inflammatory responses and manifestations of infection. Although the clinical significance of ectopic gas in the graft has not yet been established, to the best of our knowledge, no previous studies have described ectopic gas in the graft after ACCF. This study evaluated ectopic gas in the fibular graft upon follow-up CT after ACCF.
We reviewed 112 patients who underwent ACCF and follow-up CT, with a minimum follow-up period of 3 years. CT images were retrospectively reviewed to confirm the presence of ectopic gas in the graft and bone fusion. Bone fusion was defined as follows: mobility less than 2 mm between spinous processes on the flection-extension radiograph or a bone bridge on CT images.
Of the 112 patients, 30 (27%) patients had ectopic gas in the fibular grafts. Among them, ectopic gas was initially observed 3 months after surgery (early onset) in 23 (77%) patients and 6 months after surgery (late-onset) in the remaining seven (23%) patients. Upon the latest follow-up CT, ectopic gas more frequently remained in late-onset (4/7, 57%) rather than in early-onset (3/23, 13%) cases (p = 0.033). Bone fusion was not observed when CT images exhibited ectopic gas in the graft, whereas ectopic gas was not observed when CT images exhibited bone fusion.
Ectopic gas in the fibular graft was observed at both early and late-onset after ACCF; late-onset gas remained significantly. The remaining gas was strongly associated with pseudoarthrosis; therefore, pseudoarthrosis should be considered when ectopic gas in the graft is observed on CT images.
颈椎前路椎体次全切除融合术后（ACCF），患者在接受随访 CT 检查时，偶尔会发现移植物内有气腔。但大多数病例缺乏炎症反应和感染表现。虽然移植物内的异位气体的临床意义尚未确定，但据我们所知，以前的研究并未描述过 ACCF 后移植物内的异位气体。本研究评估了 ACCF 后随访 CT 时腓骨移植物内的异位气体。
我们回顾了 112 例接受 ACCF 并进行随访 CT 的患者，随访时间至少 3 年。回顾性分析 CT 图像以确认移植物内存在异位气体和骨融合。骨融合定义为：屈伸位片上棘突间活动度<2mm或 CT 图像上有骨桥。
112 例患者中，30 例（27%）患者腓骨移植物内有异位气体。其中，23 例（77%）患者在术后 3 个月（早期）首次发现异位气体，7 例（23%）患者在术后 6 个月（晚期）发现。在最后一次随访 CT 中，晚期发生的异位气体更常见（4/7，57%），而早期发生的则较少见（3/23，13%）（p=0.033）。当 CT 图像显示移植物内有异位气体时，未观察到骨融合，而当 CT 图像显示骨融合时，未观察到异位气体。
ACCF 后早期和晚期均可观察到腓骨移植物内的异位气体，且晚期的气体残留更明显。残留的气体与假关节密切相关；因此，当 CT 图像显示移植物内有异位气体时，应考虑假关节的存在。
