经小脑延髓裂入路行第四脑室手术的显微解剖研究

目的 探讨经小脑延髓裂入路到达第四脑室的解剖研究，及在不切开下蚓部的情况下如何分离此裂隙以获得最佳的手术视野。方法 应用显微外科解剖技术，对经甲醛固定、颈内动脉系统彩色乳胶灌注的10具成人尸头标本，在手术显做镜下解剖分离小脑延髓裂，观察第四脑室顶部、底部及外侧隐窝等，切开脉络膜等暴露第四脑室各区域。结果 小脑延髓裂充分暴露后，可以不切开下蚓部，即可获得第四脑室各壁的良好术野。开放小脑延髓裂可依据第四脑室壁的位置及需要暴露的程度分为3种方式：广泛型(导水管型)、外侧壁型及外侧隐窝型。结论 经小脑延髓裂入路可通过正常的解剖间隙到达第四脑室以及脑干，且术野充分，可减少手术的损伤及术后并发症。因广泛型可以最大程度显露第四脑室底部及各区域，因此可以作为该入路的标准方式。

Microanatomical study of transcerebellomedullary fissure to the fourth ventricle

Objective To refine the transcerebellomedullary fissure approach to the fourth ventricle and dissect the fissure to obtain sufficient operative view without splitting the inferior vermis. Methods The cerebellomedullary of ten cadaveric heads fixed with formalin and with their arteries perfused by color latex were dissected with microsurgical skill to observe the fourth ventricular roof, floor and lateral recess, the tela choroid and lateral walls were incised to expose each ventricle walls. Results When the cerebellomedullary fissure is appropriately and completely opened, the approach provides the sufficient view of the ventricular walls without splitting the vermis. According to the location of the ventricular wall and the extent of exposure required, the dissecting methods could be divided into the extensive, lateral wall and lateral recess types. Conclusion The fourth ventricle and brainstem can be reached via transcerebellomedullary approach through normal anatomical spaces. The extensive type should be the most frequently approach because it provides the widest opening of the cerebellomedullary fissure.