枕下正中经小脑延髓裂锁孔入路的显微解剖研究

Microanatomical study of suboccipital median transcerebellomedullary fissure keyhole approach

目的通过枕下正中经小脑延髓裂锁孔入路对第四脑室及其周围结构进行显微解剖观察,为临床应用提供解剖学依据。方法在10具(共20侧)成人尸头标本上模拟枕下正中经小脑延髓裂锁孔入路,使用显微镜对第四脑室及其周围组织结构进行解剖、观察和相关数据测定。结果 (1)枕下正中经小脑延髓裂锁孔入路可暴露第四脑室底、外侧隐窝、中脑导水管开口和脑干侧方等。(2)该入路可暴露的第四脑室底长度(37.73±0.77)mm,宽度(17.12±0.52)mm,面积(319.70±14.25)mm^2。(3)10具尸头共发现小脑后下动脉(PICA)19侧,PICA缺如1侧。同一标本双侧PICA直径差异较大,PICA下袢位置的变异也较大。结论 (1)枕下正中经小脑延髓裂锁孔入路对第四脑室的暴露范围与常规小脑延髓裂入路相仿,但存在显露角度受限、深部结构视野不佳等不足。(2)PICA与小脑延髓裂关系密切,且PICA走行分布复杂多变,术中应仔细辨认,避免误伤。

Objective To microanatomically observe the fourth ventricle and its surrounding structures via the suboccipital median transcerebellomedullary fissure keyhole（STF） approach to provide an anatomical basis for clinical application. Methods The fourth ventricle and its surrounding anatomic structures were dissected, observed and measured for relevant data under operative microscope via STF approach in 10 cadaveric heads（20 sides）. Results（1）The STF approach can expose the floor of the fourth ventricle, lateral recess, aperture of midbrain aqueduct and lateral brainstem.（2）The exposure range of the fourth ventricle floor was 37.73 ± 0.77 mm in length, 17.12 ± 0.52 mm in width, and the floor area was 319.70 ± 14.25 mm^2.（3）There were 19-sides posterior inferior cerebellar artery（PICA） from 10 cadaver heads, 1 side PICA was absent. It was founded that bilateral PICA had a large variation in diameter, and the location of the caudal loop also has great variation. Conclusions（1）STF approach can expose similar anatomic area as the conventional approach, but the exposure angle is limited and the operative view of deep anatomical structures is not clear enough.（2） PICA and cerebellomedullary fissure is closely related to each other, but the running course and distribution of PICA are complex and variable, the surgeon should pay attention to PICA and its branches.