视柱和硬膜环的内镜解剖研究

Surgical anatomy of optic strut and dural rings for endoscopic endonasal surgery

目的 研究经鼻内镜入路(EEA)中视柱和硬膜环(包括近环和远环)的解剖学特点,探讨其作为旁中央颅底入路中由鼻腔进入颅腔的“关键标志”的作用。方法 对11具新鲜灌注尸头标本和2具颅骨标本进行解剖研究,解剖在内镜或显微镜下进行。结果 视柱为蝶骨小翼的后根,呈一不规则的三棱柱体,从前床突基底部的内侧下方延伸到蝶骨体。它的上、下和后3个表面分别构成视神经管底、眶上裂顶和颈动脉沟底。视神经颈内动脉外侧隐窝(LOCR)为视柱的腹侧在蝶窦后壁形成的三角形骨性凹陷,是EEA重要的解剖标志。硬膜环为前床突上下表面的硬膜向内延续,分别从视柱的上、下表面包绕颈内动脉(ICA),形成远环和近环。近环构成海绵窦顶壁,远环则是硬膜内外间隔的界限。结论 由于视柱和硬膜环为恒定的解剖结构,而且利用它们作为参照物,可以用来识别周围复杂的神经、血管结构,所以它们是EEA的关键标志。

Objective To examine the anatomy of the optic strut and the dural rings(including the proximal and distal ring) in the endoscopic endonasal approaches(EEA), and to outline their role as a “key landmark” for the paracentral skull base approaches. Methods 11 silicone-injected fresh cadaver specimens and 2 dry crania were examined. Dissections were carried out under endoscope or microscope. Results The optic strut is an irregular triangular prism connecting the the anterior clinoid process and the sphenoid body. Its upper, lower and posterior surfaces constitute the base of the optic canal, the roof of the superior orbital fissure and the floor of the carotid sulcus, respectively. Lateral optico-carotid recess(LOCR) is a triangular bony depression formed by the ventral side of the optic strut in the posterior wall of the sphenoid sinus, and is an important anatomical landmark for EEA. The dural rings are the inward continuation of the duras on the upper and lower surfaces of the anterior clinoid process, and surround the internal carotid artery(ICA) from the upper and lower surfaces of the optic strut to form the distal ring and the proximal ring. The proximal ring constitutes the roof of the cavernous sinus, and the distal ring delimits the extradural septum. Conclusion Since the optic strut and dural rings are constant anatomical structures, and can be used to identify the complex surrounding nerve and vascular structures as reference objects, they are key landmarks for EEA.