幕下小脑上旁正中锁孔入路的显微解剖

目的 设计幕下小脑上旁正中锁孔入路,进行显微解剖学研究,为临床应用提供依据.方法 利用10具10%甲醛固定、血管灌注的成人尸头标本,模拟幕下小脑上旁正中锁孔手术入路:尸头向对侧旋转45°,采取星点与枕后隆突中点上方0.5cm、垂直于横窦的纵向下行4 cm直线形切口,横窦下直径约2.5cm的骨瓣.向下轻拉小脑方叶内侧,切断桥静脉,逐渐深入至小脑幕内侧缘,暴露中脑后外侧方,进行解剖观察.剪开并牵拉小脑幕游离缘,观察、记录增加的暴露结构.结果 将小脑方叶从小脑幕分离,可从侧面显露同侧四叠体池和环池的后部.Galen静脉位于视野的上部.牵拉同侧的大脑后动脉P3段和基底静脉可暴露第三脑室后部.切开小脑幕后向下牵拉,可增加暴露颞底内侧面(海马旁回)、大脑后动脉P2-P3段的交接处、小脑上动脉、滑车神经.结论 幕下小脑上旁正中锁孔入路具有解剖学的可行性.应用直径约2.5cm骨窗,可显露后切迹间隙、中切迹间隙内的诸多结构.此入路适合位于Galen静脉系统之下并向外扩展至中脑背外侧病变;亦可适用于颞叶后内侧区域的手术.尤其是当患者小脑幕较陡直、幕下小脑上正中入路需过度的小脑牵拉时,使用幕下小脑上旁正中锁孔入路较为有利.

Abstract：

Objective To design a paramedian supracerebelalr infratentorial keyhole approach by applying the keyhole conception and explore its feasibility.The keyhole approach is imitated and microanatomical structures are observed,which could be reference of this approach in clinical use MethodsThe paramedian supracerebellar infratentorial keyhole approach was imitated in ten adult cadaveric heads fixed in 10% formalin and perfused through inracranial vessels with colored silicone.The cadaveric head was turned to the opposite side at 45 degree angle.A vertical linear epifascial skin incision of approximately 4 cm was created from the point of 0.5 cm above the midpoint between the asterion and the inion.The craniotomy about 25 cm in diameter was made below the transverse sinus.The medial part of the quadrangular lobule was inferiorly retracted and the bridging veins were cut.The internal margin of the tentorial incisure arrived by proceeding forward over the quadrangular lobule.The posterolateral medbrain was exposed and the anatomical stnctures were obeerved under microscope.The free cut edge of the tentorium was sectioned and then retracted.The additional exposure was observed and recorded.Methods The quadrigeminal cistern and the posterior part of the ambient cistern was exposed after retracting the quadrangular lobul from the tentorial apex.The Galen venous complex can be observed in the upper part of the view.The basal vein and the P3 segment of the psterior cerebral artery have been retracted to expose the posterior part of the third ventricle.The free cut edge of tentorium was cut and then retracted.The additional exposure were the medial inferior surface of the temporal lobe (parahippocampal gyrus),the P2- P3 junction of the posterior cerebral artery,the superior cerelbellar artery,the thochlear nerve ConclusionsThe paranedian supracellar infratentorial keyhole approach is practical.Through a craniotomy appoximately25 cm in diamter,the posterior and the middle incisural space are exposed.Ir can certainly be used to deal with lesions below the veins system of Galen extending laterally the posterolateral midbrain.The lesions of the posterior temporomedial region also could be safely operatedvia this keyhole approach When the tentorial apex is more upwardly steep,the paramedian supracerebellar infratentorial keyhole approach has more advantage than the midline supracerebellar infratentorial approach whichneed excessive cerebellar retation.

Microanatomical study on paramedian supracerebellar infratentorial keyhole approach

Objective To design a paramedian supracerebelalr infratentorial keyhole approach by applying the keyhole conception and explore its feasibility.The keyhole approach is imitated and microanatomical structures are observed,which could be reference of this approach in clinical use MethodsThe paramedian supracerebellar infratentorial keyhole approach was imitated in ten adult cadaveric heads fixed in 10% formalin and perfused through inracranial vessels with colored silicone.The cadaveric head was turned to the opposite side at 45 degree angle.A vertical linear epifascial skin incision of approximately 4 cm was created from the point of 0.5 cm above the midpoint between the asterion and the inion.The craniotomy about 25 cm in diameter was made below the transverse sinus.The medial part of the quadrangular lobule was inferiorly retracted and the bridging veins were cut.The internal margin of the tentorial incisure arrived by proceeding forward over the quadrangular lobule.The posterolateral medbrain was exposed and the anatomical stnctures were obeerved under microscope.The free cut edge of the tentorium was sectioned and then retracted.The additional exposure was observed and recorded.Methods The quadrigeminal cistern and the posterior part of the ambient cistern was exposed after retracting the quadrangular lobul from the tentorial apex.The Galen venous complex can be observed in the upper part of the view.The basal vein and the P3 segment of the psterior cerebral artery have been retracted to expose the posterior part of the third ventricle.The free cut edge of tentorium was cut and then retracted.The additional exposure were the medial inferior surface of the temporal lobe (parahippocampal gyrus),the P2- P3 junction of the posterior cerebral artery,the superior cerelbellar artery,the thochlear nerve ConclusionsThe paranedian supracellar infratentorial keyhole approach is practical.Through a craniotomy appoximately25 cm in diamter,the posterior and the middle incisural space are exposed.Ir can certainly be used to deal with lesions below the veins system of Galen extending laterally the posterolateral midbrain.The lesions of the posterior temporomedial region also could be safely operatedvia this keyhole approach When the tentorial apex is more upwardly steep,the paramedian supracerebellar infratentorial keyhole approach has more advantage than the midline supracerebellar infratentorial approach whichneed excessive cerebellar retation.