Li Ze-Qun, Lan Qing
Department of Neurosurgery, Second Affiliated Hospital, Soochow University, Suzhou 215004, China.
Zhonghua Yi Xue Za Zhi. 2009 Oct 27;89(39):2754-8.
To assess the suboccipital median transcerebellomedullary fissure keyhole approach in a cadaver model by using a neuronavigation system and explore its feasibility and operative indications.
Six 10% formaldehyde-fixed adult cadaveric head and neck specimens injected with colored latex were chosen for the study. First the suboccipital median transcerebellomedullary fissure keyhole approach was performed and the anatomical structures were observed under operative microscope. The exposed floor area of the fourth ventricle and the vertical and transverse angles at the point where the line between the lateral apertures crossing the median sulcus, vertical angle at the apertures of midbrain aqueduct and the obex were measured with the aid of a frameless stereotactic navigation device. Parameters were compared with those when C1 posterior arch was removed, and also with those under conventional approach with or without C1 arch.
By means of adjusting specimen positions and the angle of operative microscope, as tela choroidea and inferior medullary velum were dissected gradually, the structures of floor, lateral recesses and lateral apertures of the fourth ventrical, vermian and aperture of midbrain aqueduct were exposed. There were no significant difference in the exposed floor area of the fourth ventricle between the keyhole approach and conventional approach (P = 0.06), and the C1 arch removal can't increase the exposed area (P = 0.84). The conventional approach have wider angles than the keyhole approach (P < 0.01), and the C1 arch removal increased the vertical angle (P < 0.05), but not the horizontal angle (P > 0.05).
The suboccipital median transcerebellomedullary fissure keyhole approach can expose similar anatomic architectures as that of the conventional approach. Thus it can be used to remove the tumors located in the fourth ventricle, dorsum of pons and medullary oblongata and cerebellar vermis.
通过使用神经导航系统在尸体模型中评估枕下正中经小脑延髓裂锁孔入路，并探讨其可行性及手术适应证。
选取6例经10%甲醛固定、注射有色乳胶的成人尸体头颈部标本进行研究。首先采用枕下正中经小脑延髓裂锁孔入路，在手术显微镜下观察解剖结构。借助无框架立体定向导航设备测量第四脑室的暴露底面面积、外侧孔连线与正中沟交点处的垂直角和横向角、中脑导水管口处的垂直角以及闩部的角度。将这些参数与切除C1后弓时的参数进行比较，也与传统入路（有或无C1弓）时的参数进行比较。
通过调整标本位置和手术显微镜角度，随着脉络丛和下髓帆逐渐被解剖，第四脑室底面、外侧隐窝和外侧孔、蚓部以及中脑导水管口的结构得以暴露。锁孔入路与传统入路在第四脑室暴露底面面积上无显著差异（P = 0.06），切除C1弓并不能增加暴露面积（P = 0.84）。传统入路的角度比锁孔入路更宽（P < 0.01），切除C1弓增加了垂直角（P < 0.05），但未增加水平角（P > 0.05）。
枕下正中经小脑延髓裂锁孔入路可暴露与传统入路相似的解剖结构。因此，它可用于切除位于第四脑室、脑桥背侧、延髓和小脑蚓部的肿瘤。
