神经内镜下扩大经鼻蝶入路至鞍上区和第三脑室的解剖

Anatomy of extended endoscopic endonasal transsphenoidal approach to the suprasellar region and the third ventricle

目的探讨内镜扩大经鼻蝶入路至鞍上区和第三脑室的解剖特点,寻找手术入路中各阶段的解剖标志点,并探讨从鞍上区进入第三脑室的不同方法。方法 4具福尔马林固定的和1具新鲜成人头颅标本,采用内镜扩大经鼻蝶入路暴露鞍上区,0°和30°镜头观察视交叉下间隙和视交叉上间隙,然后分别通过视交叉下间隙及视交叉上间隙进入第三脑室,观察第三脑室内结构,解剖过程中测量相应结构。结果鼻腔阶段的解剖标志点是后鼻孔和蝶窦开口,蝶窦阶段的解剖标志点是视神经隆起、内侧和外侧视神经颈内动脉隐窝、颈内动脉隆起、鞍底、鞍结节、蝶骨平台、斜坡凹陷,硬膜内阶段的解剖标志点是终板和灰结节。5具标本中蝶窦内骨性分隔数量范围是1～4个,其中4具标本各有2个骨性分隔延伸至颈内动脉隆起。左侧后鼻孔到同侧蝶窦开口间距是(12.1±2.3)mm,范围是9.9～15.0 mm;右侧后鼻孔到同侧蝶窦开口间距是(13.3±2.6)mm,范围是9.6～16.8mm;内侧视神经颈内动脉隐窝间距为(9.5±3.0)mm,范围是5.5～13.8mm;外侧视神经颈内动脉隐窝间距为(14.8±3.7)mm,范围是9.2～19.2mm;颈内动脉隆起间距是(16.0±3.1)mm,范围是11.3～18.8mm。视交叉下间隙和上间隙内各解剖结构显露充分。经视交叉下间隙打开灰结节可观察到第三脑室顶、后壁、底各结构,经视交叉上间隙开放终板同样可观察到第三脑室内相应结构。经终板观察第三脑室底更佳,而经灰结节观察第三脑室顶更佳,30°镜头能补充0°镜头的观察视野。结论内镜扩大经鼻蝶入路可以暴露鞍上区,并分别通过视交叉下方和上方间隙进入第三脑室,显露第三脑室内所有结构,是切除鞍上和第三脑室区域病变的安全方法。各阶段解剖标志点可以引导解剖入路方向、提供安全操作范围,必须正确地寻找和识别。

Objective To investigate the anatomic characteristics of extended endoscopic endonasal transsphenoidal approach to the suprasellar region and the third ventricle, which include searching respective anatomic landmarks in different steps and finding different routes from the suprasellar region into the third ventricle. Methods Four formalin-fixed and one fresh adult cadaver heads were dissected using an extended endoscopic endonasal transsphenoidal approach to expose the suprasellar region, followed by entering into the third ventricle through infrachiasmatic and suprachasmatic region respectively. The observing was completed with O-degree lens and 30-degree lens. Anatomic measurements were obtained. Results The anatomic landmarks were choana and sphenoid ostium in the nasal step, optic protuberance, medial and lateral opticocarotid recess, carotid protuberance, sellar floor, tuberculum sellae, planum sphenoidale, clival recess in the sphenoid sinus step, lamina terminalis and tuber cinereum in the intradural step. The numbers of the sphenoid septations were ranged from 1 to 4. There were 2 sphenoid septations inserted at the carotid protuberance in 4 cadavers. The distance between the choana and sphenoid ostium was （ 12. 1 ± 2. 3 ） mm （9.9-15.0mm） in the left nasal cavity and （13.3±2.6） mm （9.6-16.8mm） in the right nasal cavity;The distance between the bilateralmedial opticocarotid recess was （9.5 ± 3.0）mm （5.5-13.8mm）;The distance between the bilateral lateral opticocarotid recess was （ 14.8 ± 3.7 ）mm （9.2-19.2mm） ; The distance between the carotid protuberance was （ 16.0 ± 3.1 ） mm （ 11.3- 18.8mm）. Infrachiasmatic region and suprachiasmatic region were both fully exposed. After opening the tuber cinereum via the infrachiasmatic region, the roof, posterior wall and floor of the third ventricle were exposed. The third ventricle can also be exposed by opening the lamina terminalis via the suprachiasmatic region. The lamina terminalis approach was better in exposing the floor of the third ventricle, while the tuber cinereum approach was better in exposing the roof. The 30-degree lens supplemented the view of 0-degree lens. Conclusion The extended endoscopic endonasal transsphenoidal approach is feasible to expose the suprasellar region and enter into the third ventricle through two corridors, which is a safe route to remove lesions in this areas. The anatomic landmarks in different steps provide correct anatomic directions and safe operational range, which are need to be recognized and identified.