枕下正中经小脑延髓裂锁孔人路的显微外科解剖学和量化评价

目的 应用神经导航系统进行尸头颈解剖量化评价枕下正中经小脑延髓裂锁孔人路,探讨其可行性和手术适应证.方法 将6具10%甲醛固定的尸头颈标本,经有色乳胶灌注后用于实验,首先行枕下正中经小脑延髓裂锁孔入路解剖,观察各个步骤显露的解剖结构,第四脑室底的面积和中脑导水管下口与双侧外侧孔连线与正中沟交点处的垂直和水平观察角度,与去除寰椎后弓后的参数比较;并与扩大骨窗成常规人路时寰椎后弓去除前后的相应参数作比较.结果 通过调整尸头颈标本位置和显微镜的投射角度,枕下正中锁孔入路下分离小脑延髓裂后可逐层显露脉络膜、下髓帆、第四脑室底、侧隐窝、外侧孔、小脑下蚓部及中脑导水管开口.虽然锁孔入路下角度显露不如常规入路下宽(P<0.01),但显露第四脑室底的面积与常规入路下差异无统计学意义(P>0.05).去除寰椎后弓也不能增加锁孔人路下第四脑室底的显露面积(P>0.05),但可增加各点垂直观察角度(P<0.05),对水平观察角度没有影响(P>0.05).结论 枕下正中经小脑延髓裂锁孔入路与常规入路具有相似的显露面积,可以安全、微创地进行第四脑室内、脑桥延髓背侧以及小脑下蚓部等部位肿瘤手术.

Microsurgical anatomy and quantitative assessment of suboccipital median transcerebellomedullary fissure keyhole approach

Objective To assess the subooccipital median transcerebellomedullary fissure keyhole approach in a cadaver model by using a neuronavigation system and explore its feasibility and operative indications.Methods 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 wag removed.and also with those under conventional approach with or without C1 arch.Results 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 aquduct were exposed.There were no significant difference in the exposed floor area of the fourth yentricle between the keyhole approach and conventional approach(P=0.06),and the C1 arch remoral 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).Conclusion 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 tamons located in the fourth ventricle.dorsum of pons and medullary oblongata and cerebellar vermis.