Department of Orthopaedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
Spine (Phila Pa 1976). 2011 Dec 1;36(25):E1634-40. doi: 10.1097/BRS.0b013e318215552c.
Prospective analysis of preoperative and postoperative radiological data.
To assess the incidence and extent of laminar closure after Hirabayashi open-door laminoplasty, as determined by multi-detector computed tomography (CT), and to investigate the influence of this phenomenon on spinal cord compression, as shown by magnetic resonance imaging (MRI).
Although laminar closure occurs after laminoplasty, little is known about its progression or its effect on restenosis of the spinal canal.
Thirty-five patients (132 laminae) underwent classic Hirabayashi laminoplasty and were followed for at least 12 months. Multi-detector CT was performed preoperatively, at 1 week, or less, and 6 months after surgery. At each level, the anteroposterior (AP) diameter of the spinal canal and the angle of the opened lamina were measured. MRI was performed preoperatively and 1 year after surgery to evaluate the severity of cord compression based on a six-grade classification system.
The mean AP diameter and the mean opening angle increased immediately after surgery (P <0.05 each) and decreased 6 months after surgery (P < 0.0001 each), with the AP diameter and opening angle decreasing by 9.4% and 10.2%, respectively. CT at 6 months showed fusion of the hinge in 91% of opened laminae. Segments with high-grade cord compression (grade ≥3) at 1 year showed greater decreases in AP diameter and opening angle (P < 0.05).
After classic Hirabayashi open-door laminoplasty, opened laminae showed reclosure at 6 months, with approximately 10% decrease in AP diameter and opening angle. Postoperative lamina closure was associated with recurrent spinal cord compression, suggesting the need for other augmenting techniques that keep the laminae opened.
术前和术后影像学资料的前瞻性分析。
通过多层螺旋 CT（multi-detector CT，MDCT）评估 Hirabayashi 开门式椎板成形术后的板层融合发生率和程度，并通过磁共振成像（magnetic resonance imaging，MRI）研究这种现象对脊髓压迫的影响。
虽然椎板成形术后会发生板层融合，但对于其进展或对椎管再狭窄的影响知之甚少。
35 例（132 个椎板）患者行经典 Hirabayashi 椎板成形术，至少随访 12 个月。术前、术后 1 周内及术后 6 个月行 MDCT 检查。在每个节段，测量椎管前后径（anteroposterior diameter，APD）和打开的椎板角度。术前及术后 1 年行 MRI 检查，根据六级分类系统评估脊髓压迫的严重程度。
术后即刻 APD 和打开的椎板角度均增加（均 P < 0.05），术后 6 个月下降（均 P < 0.0001），APD 和打开的椎板角度分别减少 9.4%和 10.2%。术后 6 个月 CT 显示 91%的打开椎板出现铰链融合。术后 1 年脊髓压迫程度为高级别（grade ≥3）的节段，APD 和打开的椎板角度减少更明显（均 P < 0.05）。
经典 Hirabayashi 开门式椎板成形术后，打开的椎板在术后 6 个月时出现再融合，APD 和打开的椎板角度减少约 10%。术后椎板融合与脊髓再压迫相关，提示需要其他增强技术来保持椎板张开。
