Department of Radiology-Neuroradiology Division, University of Pennsylvania Health System, University of Pennsylvania Perelman School of Medicine, Hospital of the University of Pennsylvania, 219 Dulles Building, 3400 Spruce Street, Philadelphia, PA 19104, USA.
Eur J Radiol. 2013 Mar;82(3):544-51. doi: 10.1016/j.ejrad.2012.09.029. Epub 2012 Dec 3.
Postoperative CSF leak is the most common complication of endoscopic endonasal approach (EEA) to skull base lesions. Endoscopic multilayer closure of skull base defect using pedicled nasoseptal flaps (NSF) based off the sphenopalatine artery reduces CSF leaks. EEA robustly expands in surgical arena, yet postoperative imaging evaluation remains poorly studied. This work illustrates normal MR imaging appearance of skull base reconstruction utilizing NSFs during immediate postoperative period.
We retrospectively identified patients who had skull base reconstructions utilizing NSFs following EEAs and immediate postoperative-enhanced brain MRI. NSFs and free grafts were evaluated for signal intensity, thickness, configuration, enhancement, vascular pedicle of NSF, relationship in multilayer reconstruction, and defect coverage. Imaging findings were correlated with surgical technique and CSF leaks.
Twenty-eight patients had 26 multilayer reconstructions and 34 NSFs. Twenty-nine NSFs showed enhancing C-shaped arc at the skull base. Of those, 26 flaps (90%) were confidently identified by visualization of their vascular pedicles, 3 were not distinguishable from adjacent mucosa and pedicles were not identified. Five NSFs showed no enhancement (1 CSF leak). Twenty-seven enhancing NSFs approximated defects with close abutment to free grafts. One flap was displaced; one incompletely covered the defect (2 CSF leaks). Fisher exact test demonstrated an association between incomplete defect coverage and displacement of NSFs with CSF leak (P=0.05).
Endoscopic skull base reconstruction utilizing NSF has characteristic MR imaging appearance. Non-enhancing mucosal gap or displacement of NSF may indicate incomplete defect coverage, identifying patients at risk for CSF leak.
内镜经鼻颅底入路（EEA）术后脑脊液漏是颅底病变最常见的并发症。使用基于蝶腭动脉的带蒂鼻中隔-鼻甲骨瓣（NSF）对颅底缺损进行内镜多层封闭可减少脑脊液漏。EEA 在外科领域得到了广泛应用，但术后影像学评估仍研究不足。本研究展示了 EEA 术后即刻利用 NSF 进行颅底重建的磁共振成像（MRI）表现。
我们回顾性地确定了接受 EEA 并在术后即刻进行增强脑 MRI 检查的利用 NSF 进行颅底重建的患者。评估了 NSF 和游离移植物的信号强度、厚度、形态、增强、NSF 的血管蒂、多层重建中的关系以及缺损覆盖情况。将影像学发现与手术技术和脑脊液漏相关联。
28 例患者有 26 例多层重建和 34 个 NSF。29 个 NSF 在颅底显示出增强的 C 形弧形。其中，26 个瓣（90%）通过观察其血管蒂得以明确识别，3 个瓣与邻近的黏膜和蒂无法区分。5 个 NSF 无增强（1 例脑脊液漏）。27 个增强的 NSF 与游离移植物紧密吻合，接近缺损。一个瓣移位，一个瓣不完全覆盖缺损（2 例脑脊液漏）。Fisher 确切概率检验表明，NSF 不完全覆盖缺损和移位与脑脊液漏之间存在关联（P=0.05）。
利用 NSF 进行内镜颅底重建具有特征性的 MRI 表现。NSF 无增强的黏膜间隙或移位可能表明缺损不完全覆盖，从而确定有发生脑脊液漏风险的患者。
