小脑幕下小脑上锁孔入路的显微解剖研究及其初步临床应用

目的 探讨小脑幕下小脑上锁孔入路进行松果体区肿瘤手术的可行性.方法 选用16例经彩色乳胶脑血管灌注的正常尸头,模拟完成小脑幕下小脑上锁孔入路手术,进行显微结构观察,神经导航适时解剖学数据计量及分析.根据11例第三脑室及松果体区肿瘤患者个体影像学特征,以小脑幕下小脑上锁孔入路进行手术验证.结果 小脑幕下小脑上锁孔入路中,除小脑上方中央组桥静脉需离断外,其他桥静脉可良好保存.左、右内侧组桥静脉解剖游离后其间距达(35±6)mm,可满足入路的空间要求.向下牵拉小脑,可显露出松果体、Galen静脉的各属支血管、四叠体,甚至滑车神经等结构.在脉络膜后内侧动脉的内下打开第三脑室顶的下层脉络膜可进入第三脑室的后部.小脑幕外侧窦与直窦之间切开小脑幕,可向前、向上扩大手术显露空间进入幕上纵裂区.11例松果体区肿瘤直径约2～5 cm,全切8例,次全切3例,术后1例行颅后窝减压及V-P引流,1例术后短暂缄默和凝视,余无不良反应.结论 小脑幕下小脑上锁孔入路切除松果体区肿瘤时,通常不影响深部静脉系统,并能近无创地进入第三脑室,必要时可切开小脑幕显露幕上空间.该入路可有效显露松果体区相关结构,满足手术要求,是该区域手术的一种良好选择.

Microsurgical anatomy and clinical application of infratentorial supracerebellar keyhole approach

Objective To explore the feasibility of applying the infratentorial supracerebellar keyhole approach for removing tumors of pineal regiom.Methods Infratentorial supracerebellar keyhole approach was performed in 16 cadaveric heads with intracranial vessels perfused by colored later.The microscopic structure was observed.The anatomic structure was measured with Stryker Navigation System and the data were analyzed with the SPSS 10.0 software.And further,infratentorial supracerebellar keyhole approach was performed in 11 clinical cases with tumors located in the posterior third ventricle and pineal region,based on the individualized imaging features.Results Only the central group bridging veins on the cerebellum tentorial surface needed to be sacrificed under infratentorial supracerebellar keyhole approach,and other vessels could be preserved well The distance between the bridging veins of beth left and right medial group could reach (35±6) mm when they were fully dissected,thus offering enough surgical space for applying this keyhole approach.When the culmen of cerebellum was retracted,the pineal body,Galen vein and its tributary,quadrigeminal bodies,even trochlear nerve could be observed.When the underlayer choroid of the third ventricular roof was dissected medially and inferiorly to the posterior choroidal artery,the posterior third ventricle could be reached.If the tentorium of cerebellum was cut open between the straight sinus and the lateral sinus,the surgical field could be enlarged anteriorly and superiorly to the longitudinal fissure region above the tentorium.Eight of the 11 pineal region tumors sized 2 -5 cm in diameter were totally removed,and 3 were subtotally resected.For one case,posterior cranial fossa decompression and ventriculoperitoneal shunt were performed postoperatively.Another one patient suffered from transient mutism and steady fixation after surgery.Other patients had no adverse effect.Conclusions Infratentorial supracerebellar keyhole approach can be applied for removing the pineal region minors without interfering the adjacent deep venous system,and can enter the third ventricle in a nearly non-traumatic way.If necessary the tentorium can be cut open to expose supra-tentorial structures.It can be regarded as a better choice for surgeries in this region.