Neuroradiology Division, Department of Radiology, Veterans Administration San Diego Healthcare System and University of California, San Diego, San Diego, California, USA.
AJNR Am J Neuroradiol. 2013 May;34(5):1104-10. doi: 10.3174/ajnr.A3432. Epub 2013 Jan 24.
Arachnoid webs are intradural extramedullary bands of arachnoid tissue that can extend to the pial surface of the spinal cord, causing a focal dorsal indentation of the cord. These webs tend to occur in the upper thoracic spine and may produce a characteristic deformity of the cord that we term the "scalpel sign." We describe 14 patients whose imaging studies demonstrated the scalpel sign. Ten of 13 patients who underwent MR imaging demonstrated T2WI cord signal-intensity changes, and 7 of these patients also demonstrated syringomyelia adjacent to the level of indentation. Seven patients underwent surgery, with 5 demonstrating an arachnoid web as the cause of the dorsal indentation demonstrated on preoperative imaging. Although the webs themselves are rarely demonstrated on imaging, we propose that the scalpel sign is a reliable indicator of their presence and should prompt consideration of surgical lysis, which is potentially curative.
蛛网膜 webs 是一种延伸到脊髓软膜表面的硬脊膜外蛛网膜组织带，可导致脊髓背侧局部凹陷。这些 webs 往往发生在上胸段脊柱，并可能导致脊髓的特征性畸形，我们称之为“手术刀 sign”。我们描述了 14 例影像学检查显示手术刀 sign 的患者。13 例接受 MRI 检查的患者中有 10 例显示 T2WI 脊髓信号强度改变，其中 7 例患者还显示与凹陷水平相邻的脊髓空洞症。7 例患者接受了手术，其中 5 例显示蛛网膜 webs 是术前影像学显示的脊髓背侧凹陷的原因。尽管 webs 本身在影像学上很少显示，但我们提出手术刀 sign 是其存在的可靠指标，应提示考虑手术松解，这可能是有效的。
