【作者】 田喜光；

【导师】 丁自海；

【作者基本信息】 南方医科大学 ， 人体解剖学与组织胚胎学， 2009， 博士

【摘要】 研究背景斜坡及枕骨大孔腹侧区位于颅底的中部,是脑膜瘤、血管瘤、脊索瘤、淋巴瘤、胆脂瘤等疾病的好发区,位置深在,与垂体、脑干、第Ⅲ～Ⅷ对脑神经、基底动脉、颈静脉球及海绵窦等重要结构关系密切,特别是承载着延髓和脑桥下部,加之周围又有骨性结构阻挡,常规手术入路难以到达,给该区域的手术治疗带来很大困难。针对斜坡区不同手术入路的研究,是近年来颅底外科和临床应用解剖学研究的热点。斜坡区手术入路虽然较多,包括颞下、枕下、极外侧、经口-咽及经鼻蝶等入路,但迄今为止没有一种入路适用于所有病例。这些不同的手术入路与斜坡区的特殊解剖结构直接相关,了解斜坡区及其周围各解剖结构的形态与毗邻关系,对于最佳手术入路的选择意义重大。以内镜技术为代表的微创外科是当今临床医学的重大进步之一。自从1910年Lespinasse首次报道使用内镜进行脑积水外科手术后,1978年Bushe及Jankowski相继报道了鞍区手术中内镜的应用及经蝶内镜下鞍区肿瘤的手术治疗,之后Jho和Cappabianca等进一步证实了内镜下经鼻蝶手术的可行性及其良好的手术效果。但是,由于受到手术器械及颅底复杂解剖结构的限制,内镜经鼻蝶入路的临床应用一直未能广泛开展,仅被用于脑脊液鼻漏修补术、视神经管减压术、垂体腺瘤及侵犯颅内的鼻窦黏液囊肿等疾病的外科治疗。近年来,随着显微内镜设备和器械的不断改进,使得经鼻内镜下颅底手术逐渐增多,目前已经成为临床垂体腺瘤的首选治疗方法。自1987年Weiss首先命名并描述了“扩大的经蝶窦入路”,借助于临床医师手术经验的不断积累,以及对于颅底中线部位解剖结构的深入研究,除鞍区外,其应用范围逐步向颅前窝底、翼腭窝、眶尖、鞍上、海绵窦、斜坡及颅颈交界区扩展,在垂直方向上可以从鞍底暴露至枕大孔,在水平方向上可以暴露至双侧下颌关节,侧方可暴露至颈内动脉、卵圆孔、圆孔、岩尖和颈内静脉球。该手术入路具有以下突出的优势:①手术操作相对简单;②手术入路更直接,利用该手术入路可以迅速地到达手术区域;③手术操作过程完全是通过正常的生理通道来完成;④手术对于正常神经血管骚扰小。随着内镜成像技术的日益完善和成熟,不少学者仍在尝试如何继续扩大其手术显露范围。本研究拟通过斜坡区的应用解剖学研究,旨在掌握扩大的经鼻手术入路。目的1、为扩大的内镜下经鼻斜坡及枕骨大孔区手术提供解剖学依据。通过对斜坡及枕骨大孔腹侧区及其周围结构的解剖学描述和测量,掌握斜坡及其周边的解剖特点,建立该手术入路的解剖标志点及安全操作范围。2、结合当今先进的医疗影像设备,探讨内镜解剖、断层解剖以及影像解剖之间的比对关系。3、通过在新鲜尸头标本上完全模拟内镜下斜坡区的手术操作,进一步验证手术标志点的实用性,验证并确定手术安全范围、避免术中误伤重要解剖结构。而且对于今后经鼻内镜手术器械的之制作及改进提供解剖学依据。4、为今后研制经鼻入路至斜坡与颅颈交界区虚拟手术软件积累经验,为该手术入路的广泛应用提供解剖学基础。材料与方法1.干性头颅标本20个,进行骨性颅底斜坡周围解剖标志点的测量;福尔马林固定完整头颈部标本20例,动脉灌注红色乳胶,完全模拟经鼻手术入路,解剖观察经鼻蝶至斜坡及枕骨大孔腹侧区手术入路的解剖学特点,确立手术标志。并利用游标卡尺（精度0.02mm）和圆规,测量该区域手术入路相关的重要解剖结构。测量翼管、咽鼓管咽口、破裂孔、舌下神经外口、颈内动脉管、寰枢椎处椎动脉、寰枢椎处颈内动脉、枕髁前缘内侧距正中线的距离。测量前鼻棘距咽结节、枕骨大孔前缘中点、寰椎前结节的距离。参照国内骨性颅底斜坡区的各结构的形态、测量及毗邻关系以及断层解剖进行对照、SPSS13.0软件统计学分析研究。2.新鲜完整头颈部标本5例,利用直径为4mm,长度为18cm的0°及30°鼻内镜及部分内镜器械,完全模拟内镜经鼻入路。验证确定的手术标志,了解内镜下手术区的解剖学特点。3.新鲜尸头标本的64排CT骨性结构三维重建、动脉内灌注氧化铅后的血管三维重建及1.5T MRI平扫后影像资料之间的影像解剖学对比研究。4.随机选取20例健康体检者64排头颅螺旋CT扫描资料,进行颅底重要解剖结构的CT测量及手术通道涉及的重要骨性标志及血管的三维重建,并将测量结果与固定标本的测量结果进行对比研究。5.临床研究:扩大的内镜下经鼻蝶入路至斜坡及枕骨大孔腹侧区应用解剖学研究应用于临床,进一步明确术中需要特别注意的关键的解剖结构。结果与讨论1.骨性斜坡的测量骨性斜坡由枕骨基底部和蝶骨体共同构成,向前上约呈45°角倾斜。斜坡上界为鞍背,下界为枕骨大孔前缘,其两侧毗邻破裂孔、岩枕裂、颈静脉孔、舌下神经管内口等结构。枕骨大孔前缘至鞍背的距离为（45.51±2.60）mm,枕骨大孔前缘的厚度为（3.45±0.69）mm,舌下神经根穿经枕骨大孔侧壁的舌下神经管出颅,两侧舌下神经管内口的间距为（25.55±3.07）mm;蝶鞍底至两侧内耳门下壁连线的垂直距离为（20.1±1.8）mm;岩枕裂的后端为颈静脉孔,孔的内侧有颈静脉结节,该结节距颈静脉孔神经部约1～2cm,结节的后下方为舌下神经管的内口。中斜坡骨质厚度为（7.19±1.23）mm。2.内镜经鼻颅颈交界手术的手术标志包括:中鼻甲、后鼻孔、咽鼓管咽口、鼻咽部粘膜、头长肌和颈长肌、枕骨大孔前缘中点、寰椎前结节。经鼻入路完全暴露颅颈交界区,最短距离为（89.60±2.52）mm,蝶窦前下壁和下斜坡磨除范围分别以两侧翼管和破裂孔为界,各自距中线距离:翼管左侧（9.25±0.55）mm、右侧（9.19±0.50）mm,破裂孔左侧（10.64±0.83）mm和右侧（10.75±0.84）mm。3.颅底斜坡区相关解剖结构的观测3.1颈内动脉岩内段颈动脉管以膝部为界分为垂直段和水平段。颈内动脉自颈动脉管外口垂直上升,继而折转向前内呈水平方向走行至破裂孔,折转向上进入颅腔,续为海绵窦段。颈内动脉岩内段除在颈动脉管入口处有致密纤维组织附着使之固定于岩骨下面外,易于自颈动脉管结缔组织分离。分为垂直部和水平部。其重要毗邻关系是垂直部的入口与后方颈静脉球窝间的骨板。3.2 Dorello管及其内容物Dorello管是位于上斜坡外侧呈不规则形的骨纤维管道,其内主要有展神经和岩下窦等通过。展神经在颅后窝硬膜入口处位于后床突下方,在颅后窝岩斜坡硬膜内几乎垂直上行达Dorello管入口处,继而呈扁平状经过Dorello管的外1/3或中1/3。岩下窦起自海绵窦后部,与展神经伴行穿Dorello管,经岩枕裂至颈静脉孔注入颈内静脉。3.3颈静脉孔的形态和毗邻颈静脉孔为岩枕裂后端的扩大部,位于下斜坡的外侧,形态及大小多变,以颞骨和枕骨的颈静脉突分隔颈静脉孔,则颈静脉孔为单孔,即孔被不完全分隔成后外侧部（静脉部）和前内侧部（神经部）,此型左、右侧分别占86%和80%。以骨桥分隔者颈静脉孔则为双孔,此型左、右侧分别占14%和20%。左、右侧颈静脉孔的面积分别为（4.6±2.8）mm和（6.2±3.0）mm²。其中右侧面积大于左侧者占60%,左侧面积大于右侧者占18%,两侧面积相等者占22%。舌咽神经位于前内侧部三角凹内的硬膜鞘中,位置恒定。迷走神经和副神经位于同一硬膜鞘内,迷走神经在前,副神经在后,二者在颈静脉孔内的位置有3种情况:①位于前内侧部,占93%;②位于两部之间的骨纤维隔内,占6.5%;③位于后外侧部的内侧,占0.5%。颈内静脉位于后外侧部,位置恒定。两颈静脉孔的间距为45.3mm。舌咽神经、迷走神经和副神经位于颈静脉孔前内侧部,即神经部,而颈内静脉位于后外侧部,即血管部。孔的内侧为颈静脉结节,距颈静脉孔神经部（1.53±0.43mm）。3.4斜坡与脑桥和延髓腹侧的关系在矢状切面上,斜坡面对脑桥、延髓的腹侧,其中以与脑桥基底部、延髓上1/2相贴最紧。基底动脉在脑桥基底沟下1/3段和脑桥延髓沟处由椎动脉汇合而成的各占33.3%和66.7%。至基底沟上端近脚间窝处分为大脑后动脉,全长（28.5±1.2）mm,占斜坡全长的3/4.。基底动脉下、中、上1/3段的外径分别为5.3、4.6和4.3 mm。脑桥、延髓前正中静脉在正中线上迂曲走行,外径0.3 mm;在其外侧0.5cm处有平行走行的前外侧静脉,外径约0.3mm;上述静脉间有3～5条横行静脉相交通,其外径约0.3 mm。脑桥臂中份和脑桥延髓沟正对斜坡的中1/3段和中、下1/3段交界处。橄榄体位于延髓前外侧,脑桥延髓沟的下方,其上后方3～4mm处为面神经、前庭蜗神经根,后方为舌咽神经、迷走神经和副神经根,前方为舌下神经根。3.5破裂孔的毗邻颈静脉孔为岩枕裂后端的扩大部,位于下斜坡的外侧,以颞骨和枕骨的颈静脉突分隔颈静脉孔,则颈静脉孔为单孔,即孔被不完全分隔成后外侧部（静脉部）和前内侧部（神经部）,此型左、右侧分别占86%和80%。以骨桥分隔者颈静脉孔则为双孔,其中右侧面积大于左侧者占60%,左侧面积大于右侧者占18%,两侧面积相等者占22%。舌咽神经位于前内侧部三角凹内的硬膜鞘中,位置恒定。迷走神经和副神经位于同一硬膜鞘内,迷走神经在前,副神经在后,二者在颈静脉孔内的位置有3种情况:①位于前内侧部,占93%;②位于两部之间的骨纤维隔内,占6.5%;③位于后外侧部的内侧,占0.5%。颈内静脉位于后外侧部,位置恒定。两颈静脉孔的间距为（45.34±2.92）mm^[2]。4.20例健康体检者头颅CT测量结果经鼻入路完全暴露中下斜坡,最短距离为（88.65±2.55）mm;蝶窦前下壁和下斜坡磨除范围分别以两侧翼管和破裂孔为界,两者距中线的CT测量距离分别为:（9.16±0.49）mm和（10.70±0.96）mm。应用VR法或SSD法进行颅底骨质及血管三维重建后表明:头颈CT扫描除可显示骨性鼻道、鞍区、中脑、脑桥、延髓、脊髓等组织外,能更直观清楚地显示重要的颅底骨性结构,包括:破裂孔、内耳门、颈静脉孔、颈静脉结节、岩骨、斜坡（大小、形态）、乳突、内听道、枕骨大孔（大小、形态）、枕骨裸、枕外隆凸、寰椎前后弓、寰椎关节面、咽结节、枕骨大孔前缘、舌下神经管、颈内动脉管等,应用测量软件能较精确地测量相关结构之间的距离:包括内听道、寰椎前后弓、咽结节、枕骨大孔前缘、破裂孔、舌下神经管、颈内动脉管等距中线的距离,以及观察骨性鼻道的形状、内听道的大小、枕骨大孔的大小、斜坡的形状等,有时还可显示颅神经之间的关系。重建斜坡及枕骨大孔腹侧区三维图像,可模拟经鼻该区域手术体位下的大体解剖,为术中比对提供有价值的参考。5.临床研究表明,以下解剖结构关乎经鼻斜坡手术的成败:5.1鼻中隔鼻中隔主要由鼻中隔软骨及筛骨垂直板组成。构成经鼻手术通道的最前部分。5.2蝶窦蝶窦是蝶骨体中的一个含气腔。蝶窦的形态及大小的变化较大,蝶窦口是确定蝶窦中线的解剖标志,均位于鼻腔上鼻甲后方的蝶筛隐窝内,是定位鞍底的标志,其窦口形状可呈椭圆形、圆形或裂隙状。鼻小柱根部至蝶窦口下极和蝶窦底的距离平均60mm和14mm。这些解剖数据有助于寻找蝶窦口。咬开蝶窦前下壁后,可以显露鞍底。蝶窦内可有中隔,蝶窦横径平均为22mm,前后径为22mm,垂直径为20mm。蝶窦外侧壁与视神经和颈内动脉关系密切,视神经管隆突位于蝶窦外侧壁上部,而颈内动脉隆突位于蝶窦外侧壁的鞍底下部。5.3视神经视神经管内侧壁多数与蝶窦相邻。视神经管突入窦腔内形成隆起,该隆起超过管径1/4以上的占16.2%。由于蝶窦的变异较多,筛窦又常向后侵入蝶窦上方。因此视神经管的内侧壁毗邻关系较复杂,有时由于蝶窦中隔偏曲,两侧的视神经管与一侧蝶窦相邻。蝶窦外侧壁与视神经管的毗邻关系取决于后筛房的气化程度,视神经管全部或大部位于蝶窦外侧壁。5.4颈内动脉颈内动脉隆起可分为鞍后段、鞍下段及鞍前段。颈内动脉于岩尖出颈内动脉管口进入颅内,经破裂孔向上进入海绵窦,在海绵窦内前行,于前床突水平向上穿出海绵窦顶,然后转向前床突内侧上行。上述行程紧贴蝶窦外侧壁,并形成一条凸向窦内的压迹。有部分颈内动脉在蝶窦内形成隆起,由于蝶窦气化程度的不同,形成隆起的出现率也不同,同样由于蝶窦中隔的偏曲,有时可出现一侧蝶窦与两侧颈内动脉相邻。蝶窦内的颈内动脉压迹骨壁厚约1.0mm,有时自然缺损。5.5蝶腭动脉及其分支蝶腭动脉为上颌动脉的终支,从翼腭窝向前内上方走行,在中鼻甲后端稍上方的蝶腭孔进入鼻腔,蝶腭孔至鼻小柱根部和蝶窦口下极的距离约为62mm和13mm。蝶腭动脉在鼻腔的分支主要有鼻腔外侧动脉和鼻中隔后动脉。鼻腔外侧动脉通常分为上、中、下鼻甲动脉,分别从各鼻甲的后端进入相应的鼻甲。鼻中隔后动脉一般分为上下两支,从蝶窦前壁蝶窦口下方转入鼻中隔。近蝶窦口的称鼻中隔后动脉上支,离蝶窦口较远的一支称鼻中隔后动脉下支。鼻中隔后动脉上下支至蝶窦口下极的距离约为3.5mm和6.5mm;至蝶窦顶壁距离为14mm和16mm;至蝶窦底壁的距离为11mm和7.5mm。了解这些数据的目的主要在扩大经蝶入路时需将蝶窦前壁尽量扩大又不至于损伤血管而出血。5.6海绵窦及海绵间窦海绵窦是鞍旁由眶上裂至岩尖的硬膜折叠形成的五面体结构。左右海绵窦间有前、后海绵间窦相连,在鞍底硬膜间可有下海绵间窦,鞍背后方可有后海绵间窦及鞍背窦,其与两侧海绵窦、岩上窦、岩下窦相通。与扩大经蝶进路斜坡肿瘤切除术相关的海绵间窦主要是下海绵间窦、后海绵间窦、基底窦及鞍背窦。结论1.通过斜坡区骨性解剖结构及其毗邻关系的解剖学研究,可提高对整个颅底斜坡区构成及其解剖特点的熟悉程度,为临床该区域手术入路的研究提供解剖学基础。2.通过固定尸头标本进行模拟内镜手术研究,收集并获得了与该手术入路相关的内镜解剖学数据,明确并确立了术中标记点,通过测量颅底重要解剖结构之间的距离,可以获得内镜手术的安全操作范围。3.对于同一组新鲜尸头标本,分别采用头颅CT及MRI平扫、灌注氧化铅显影剂后的再次CT扫描以及骨与血管的三维重建,可以获得更多的实验数据,对于临床指导意义巨大。4.内镜下完全模拟手术操作表明,内镜经鼻入路可充分显露颅颈交界区腹侧结构,完全达到模拟内镜下操作过程,对于临床医师术前强化训练意义重大。5.通过将扩大的内镜下经鼻入路研究应用于临床,达到了基础与临床的紧密结合,进一步阐明了哪些是决定临床手术能否成功的关键解剖结构,直接指导临床医师开展扩大的内镜经鼻斜坡区病变的手术治疗。更多还原

【Abstract】 BackgroundClivus and ventral region of foramen magnum locates in the middle part of skull basis,where meningioma,hemangioma,chordoma,lymphoma and cholesteatoma often occur.Deeply located,and having close relationship with important structures such as pituitary,brainstem,Ⅲ～Ⅷof the cranial nerve,basilar artery,glomus jugulare and cavernous.Especially,holding the lower part of medulla oblongata and pontine in addition to the surrounding structural barriers of osteoarthritis,it is very difficult for the conventional surgery to reach this area and causing great difficulty in surgical treatment in this region.Although there are relatively many types of clivus region surgery,including various entry routes,through infratemporal,suboccipitals extreme lateral,passingⅠ-pharyngeal and nasal tip,now a general entry route has not been found yet to apply to all the cases.These different surgical entry routes have directly relationship with the special anatomical structure of clivus region.Knowing its patterns and adjacent relationships between clivus region and its surroundings,it is helpful to find the best entry route.Researches on different entry routes of clivus region surgery have become the hot spot of skull base surgery and anatomy of clinical application in recent years.Endoscopy,the symbol of Minimally Invasive Surgery,has been the important progress in now days clinical application.In 1901,Lespinasse used endoscopic in hydrocephalus operation first.In 1978 Bushe had reported the endoscopic surgery in saddle area.Jankowski had conducted endoscopic surgery to cure tumor in saddle area.Later Jho and Cappabianca had also conducted endoscopic surgery of trans nasal approach and proved the feasibility and good surgical result.Due to the complex anatomical structure of skull base,the procedure has certain constraints in clinical application and can only be applied in surgical treatments such as: cerebrospinal fluid and rhinorrhea repair surgery,optic canal decompression,pituitary adenoma and violations of intracranial mucocele of the paranasal sinuses.With the continuous development of the micro-endoscopic equipment and technology,the surgical treatment techniques through neb-skull base can be widely used and has become the first chosen treatment for pituitary adenoma in clinical application. Thanks to the continuous accumulation of surgery experiences,and more comprehensive researches on endoscopic anatomical structure of skull base,except in the sellar region,the surgery entry routes has been continuously expanded,and has gradually been applied to surgical treament in various skull base lesion regions such as pterygopalatine fossa,orbital apex,cavernous,petrous apex,clivus and craniocervical junction.In 1987,Weiss had first named and described the expanded entry route through Sphenoid.With the continuous improvement in the surgical regions,gradually expanding to the regions of anterior cranial fossa,saddle area, cavernous,clivus,and craniocervical junction.The extended endoscopic endonasal approach,in vertical direction,can be exposed from bottom saddle area to foramen magnum,in horizontal direction,can be exposed to bilateral temporomandibular joint, from sides can be exposed to internal carotid artery,foramen ovale,foramen rotundum,petrous apex petrous apex and jugular vein ball.Extended endonasal approach has unique advantage:simple,direct,quickly reaching the surgical region. With comprehensive development of endoscopic technology,many scholars have tried surgical indications to continuously extend the endoscopic endonasal approach in clivus region.This research is based on the research of applied anatomy of the deeply located clivus region structure for endonasal approach which has close important structural relationships with pontine,the ventral medulla oblongata, internal carotid artery,basilar artery,glomus jugulare and cavernous.This research aims to study the endoscopic anatomy of surgical entry routes,observe exposure region,determine anatomy indication,and provide more detailed information of anatomical,comparative anatomy,endoscopic anatomy and anatomical measurements for clinical application in lesion clivus region with surgical treatment of extended endoscopic endonasal approach.Objectives1.Establish surgical landmarks for the surgery through neb-ventral craniocervical junction under endoscopic,provide anatomical basis.To conduct the micro-anatomical descriptions and endoscopic description on the surgery via endonasal approach to clivus and ventral foramen magnum and its surrounding structures and provide substantial morphological evidence and basic anatomy for clinical doctors to conduct the extended endoscopic endonasal approach to clivus and ventral foramen magnum surgery under the endoscopic.2.In the same surgical region to find the comparative relations among endoscopic anatomy,sectional anatomy and imaging anatomy and provide clinical doctors with detailed images and data information.3.This research has conducted measurement of relevant data on low-middle part bone structure of clivus.With these data measurement,it is importantly meaningful not only to identify surgery safety scope to avoid accidental injury of important structure but also very helpful to the selection of suitable endoscopic equipment and provide a quick and easy entry route for clinical doctors to conduct the surgery in clivus region.4.To accumulate experiences in developing virtual software for the extended endoscopic endonasal approach surgery on region of clivus and craniocervical junction.Materials and methods 1.20 Dry skull specimens,conduct measurement of the anatomical landmark points on the surroundings of the clivus of osseous skull base;20 formalin-fixed complete head and neck specimens,to fill red color emulsion in artery,to complete simulate surgical endoscopic endonasal approach,conduct anatomical observation on anatomical characteristics of surgical entry route that passes nasal to clivus and ventral foramen magnum and establish surgical landmarks.And utilize vernier caliper (precision 0.02mm) and compasses to gauge the important anatomical structures related to the surgical entry road in this region.①Pterygoid canal,pharyngeal opening of eustachian tube,the breakdown hole,outside ostium of hypoglossal nerve,internal carotid artery,atlantoaxial vertebral artery,atlanto-axial internal carotid artery,the distance from front edge of the medial occipital condyle to midline.②Anterior nasal spine away from the pharyngeal tubercle,front edge midpoint of foramen magnum, distance of anterior tubercle of atlas.Study from national references on the forms different structures of osseous skull base clivus region,conduct comparison on measurements and adjacent relations and sectional anatomy,SPSS13.0 software statistical analysis research.2.Five fresh complete head and neck specimens,fill in red color emulsion. Utilize 4mm diameter,18cm length,0°and 30°nasal endoscopic and part of endoscopic equipments,completely simulate endoscopic endonasal approach.Prove identified surgical landmarks;understand anatomy of endoscopic surgical region to provide anatomical evidence for further development of clinical operation.3.The same fresh body head specimens,surgical passage 64-row CT bone structure,three-dimensional reconstruction,vascular three-dimensional reconstruction after filling PbO in artery and comparison study of imaging information after 1.5tMRI scanning.4.Randomly choose 20 healthy people’s scan information from 64-row spiral skull CT;conduct CT measurement of the important anatomy structures of skull base and surgical passage related important bone vascular three-dimensional reconstruction,and conduct comparative study on the measurement results with that of the fix specimens. 5.Clinical research:expand the clinical operation and applied anatomy research on endoscopic endonasal approach to clivus and ventral foramen magnum.Results and Discussion1.Mesurment of osseous clivusOsseous clivus is formed by occipital base and sphenoid body,about 45°leaning forward.Slop upper border is sellar region back,lower border is front edge of foramen magnum,the both sides border by foramen lacerum,rock pillow crack, jugular foramen,inside mouth of hypoglossal canal and other structures.The distance between the front edge of foramen magnum to the back of sellar region is (45.51±2.60)mm.The thickness of anterior margin of foramen magnum is(3.45±0.69)mm.Hypoglossal nerve root through pass sidewall of foramen magnum of hypoglossal canal;inner ears door locates at the inside sidewall of 1/3 front of rock cone;the distance from front edge of inner ears doors to the exterior edge of tuberculum sellae is(25.55±3.07)mm;the vertical distance between the sellar back and the line connecting the bottom walls of the both sides inner ears doors is (20.1±1.8)mm;the thickness of inner ears upper bone wall is(7.19±1.23) mm.2.The surgical landmark points for endoscopic pass nasal to craniocervical junction include:Middle turbinate,choanal,Pharyngeal opening of eustachian tube, nasopharyngeal mucosa opening,nasopharynx mucosa,longus capitis and longus colli,front edge of midpoint of foramen magnum,anterior tubercle of atlas.The endoscopic endonasal approach completely expose the craniocervical junction region, its shortest distance is(89.75±2.80)mm,the range of lower clivus toward both sides of stripping bone window is(10.75±0.63)mm;Differences have not been not found in other left and rights landmarks indication.3.Observation on skull base clivus region relevant Anatomical structure3.1 The Petrous bone section of internal carotid arteryDivided by the knee part,the carotid artery is identified as vertical section and horizontal section.Internal carotid artery ascends vertically from the outside mouth of carotid artery,then bend and turn forward inside appearing vertical to the foramen lacerum,bend and turn upward to cranial,then comes to the cavernous section. Internal carotid artery petrous bone section,except the entry point of carotid artery where the dense fibrous tissues attach to fix under the petrous bone,is easy to separate from the connective tissue of carotid artery.3.2 Dorello tube and its contentsDorello tube locates at the upper clivus exterior side irregular-shaped fibrous pipe,mainly passed by abducens nerve and the petrosal sinus.Abducens nerve locates at the entrance of Posterior fossa subdural,(12.24±3.5)mm under the rear-clinoid, distance between both sides is(19.71±1.79)mm.Abducens nerve inside clivus subdural behind the skull,almost vertically upward(5.07±1.43)mm to the Dorrello tube entrance,then becomes flat passing Dorello tube outside 1/3 or middle 1/3.From petrosal sinus to rear part of Cavernous,parallels with abducens nerve and pass through Dorello tube,from petrooccipital fissure to Jugular foramen and inject into jugular vein.3.3 The form of the jugular foramen and the adjacentJugular foramen is the extended area of the rear petrooccipital fissure,locates at the lower part of clivus lateral,forms and sizes are changeable,jugular foramen uses the jugular vein tip of temporal bone and occipital bone to separate jugular foramen, and jugular foramen is single hole,which means incompletely separated into rear exterior section(intravenous section)and front interior section(nerve section),in this form,left and right side respectively has 86%and 80%.Separated by osteopontin, jugular foramen is double-holed,in this form,left side and right side respectively has 4%and 20%percent.The areas of left and right side Jugular foramen respectively are (4.6±2.8)mm~2 and(6.2±3.0)mm~2.The possibility is 60%that right side area is larger than left side area,18%that left side area larger than right side area,22%that the two sides’ area is the same.Glossopharyngeal nerve locates at the rear medial part inside the dural sheath within Concave triangle,position constantly fixed.Vagus nerve and accessory nerve locate inside the same Dural sheath,vagus nerve at front accessory nerve at rear,these two nerves’ locations have 3 situations:①locates at anteromedial part,has 93%;②Inside the Fibrous septum between the two parts,has 6.5%;③ Locates at the medial of rear lateral part,has 0.5%.Jugular vein locates at rear lateral section,position constantly fixed.The distance between two jugular foramen is 45.3mm.Glossopharyngeal nerve,vagus nerve,accessory nerve locate at the anteromedial part of Jugular foramen,also the nerve section,and jugular vein locates at the posterolateral section,also the vascular section.The medial of the hole is jugular tubercle,(1.5±0.43)mm from the Jugular foramen nerve section.3.4 Relations among clivus and Pontine and Ventral medulla oblongataOn the sagittal section,clivus faces pontine and ventral medulla oblongata, pastes most tightly with the pontine base and 1/2 on medulla oblongata.Basilar artery is at the 1/3 section of basilar pontine sulcus with rostral pontine sulcus,which is formed by convergence of vertebral artery,respectively occupies 33.3%and 66.7%. From upper edge of basilar sulcus,close to the interpeduncular fossa is posterior cerebral artery,whole length(28.5±1.2)mm,occupies 3/4 of the entire clivus.The length of 1/3 section of lower,middle and upper basilar artery respectively is 5.3mm, 4.6mm and 4.3mm.Intravenous vein at the front middle of pontine and medulla oblongata winds along the midline,exterior diameter 0.3mm;0.5cm from its lacteral runs the parral anterolateral vein,exterior diameter about 0.3mm;between the above mentioned Intravenous veins,there are 3 to 5 horizontal running veins intersecting,its exterior diameter is about 0.3mm.The middle part of pontine arm and pontine medullary sulcus rightly faces the border of the 1/3 middle section and 1/3 middle lower section of clivus.Olivopontocerebellar locates at the anterolateral part of medulla oblongata,under the rostral pontine sulcus,3-4mm above it is the facial nerve,vestibular cochlear nerve root,at its rear part locates the glossopharyngeal nerve,vagus nerve and accessory nerve root.Its front part is hypoglossal nerve root.3.5 The adjacent of foramen lacerumForamen lacerum locates at the lacteral of upper clivus,the irregular hole crack between the petrous apex,occipital base and posterolateral part of sphenoid body, about 1cm in diameter,the lower half of the hole is sealed by fibrocartilage,and only tiny Blood vessels and nerves pass through it.Internal carotid artery passes upward its upper half,turn inward to intracalvarium.The hole’s front boundary line is sphenoid body,the root of pterygoid process and ala magna ossis sphenoidalis, posterior and lateral borders by the tip of petrous bone section,medial is the occipital base.The distance between the inside edges of the two foramen lacerum is (18.0±1.9)mm.4.20CT measurement results of healthy examined peopleUnder endonasal approach,completely exposing middle and lower parts of clivus,the shortest distance is(89.75±2.80)mm;The ranges of stripping the inferior wall of sphenoid sinus and the lower clivus were bounded by pterygoid canal and foramen lacerum,and the CT measured distances from the median line were(9.37±0.59)mm and(10.75±0.63) mm respectively.The Skull base and blood vessel three-dimensional reconstruction results:thin layer head and neck CT scan can clearly display,besides tissue such as midbrain,pontine,medulla oblongata,spinal cord,important skull base bone structures,which includes petrous bone,clivus, mastoid,interior auditory,rear and front arch of atlas,articular surface of atlas, pharyngeal tubercle,basion,foramen lacerum,hypoglossal canal,internal carotid artery,etc.Applying the measurement software can accurately measure the distance of relevant structures,which includes the distance from interior auditory,rear and front arch of atlas,pharyngeal tubercle,front edge of foramen magnum,foramen lacerum,hypoglossal canal,Internal carotid artery canal to the midline.The applied software can observe the shape of osteoarthritis of meatus.The size of interior auditory,the size of Foramen magnum,the shape of clivus,etc.Sometime,it can also display the relations of Cranial nerves.Head neck three-dimensional reconstruction of spiral CT can more directly display the anatomical structure of the nasus osseus passage,sellar region,clivus,rear and front arch of atlas,which includes clivus region(size,form),foramen magnum(size,form),foramen lacerum,jugular tubercle, inner ear door,jugular foramen,hypoglossal canal,condylus occipitalis,external occipital protuberance,etc.This group all has relatively well displayed the structure mentioned above.The three-dimensional image reconstruction by method VR or SSD of clivus and ventral foramen magnum can simulate the approximate anatomy of the region of endonasal approach surgical position and provide valuable reference for surgical comparison.5.Clinical research demonstrates the following anatomical structures relating the success and failure of the surgery before endonasal approach.5.1 Nasal septumNasal septum is mainly constructed by septal cartilage and perpendicular plate of ethmoid bone,forming the most front region of pass nasal surgical passage.5.2 Sphenoid sinusSphenoid sinus is a aerated space within corpus ossis sphenoidalis.Its forms and sizes can vary largely.The opening of sphenoid sinus is the anatomical landmark to determine the sphenoid midline,all locates inside the sphenoethmoidal recess ethmoid fossa of the rear turbinate on nasal cavity,which is the landmark to define the bottom of sellar region.Its ostium shapes can vary in oval,round or slit-shaped. The average distance from nasal columella root to the low end of sphenoid sinus ostium and the bottom of sphenoid sinus is 60mm and 14mm respectively.These anatomical data is helpful to identify the location of sphenoid sinus.After cracking open the anterior wall of sphenoid sinus,the sellar region is exposed.In side the sphenoid sinus,there can be septal,its horizontal diameter averages at 22mm,rear and front to rear diameter 22mm,vertical diameter 20mm.The lateral wall of sphenoid sinus has close relations with optic nerve and internal carotid artery,the eminence of optic nerve canal locates at upper part of lateral wall of sphenoid sinus, and the eminence of internal carotid artery locates at the bottom of saddle area of the lateral wall of sphenoid sinus.5.3 Optic nerveThe interior walls of most optic nerves closely border with sphenoid sinus.Optic nerve canal tips enter the sphenoid chamber to form protuberans,16.2%of the above mentioned protuberans is larger than 1/4 of its canal diameter.Since sphenoid sinus change very often,ethmoid also often invades the upper part of sphenoid sinus from behind,the ajacent relations of interior wall of optic nerve canal is relatively complex. Sometime since the sphenoid sinus septal is bent,the optic nerve canal from both sides is bordered with one side of the sphenoid sinus.The adjacent relation of The Lateral wall of sphenoid sinus and optic nerve canal is determined by the the extent of gasification of the rear ethmoid chamber.The entire or the most part of optic nerve canal locate at the lateral wall of sphenoid sinus.5.4 Internal carotid arteryThe Internal carotid artery protuberans can be divided as rear saddle area,low saddle area and front saddle area.The Internal carotid artery enters intracalvarium at the petrous apex of internal carotid canal,through foramen lacerum to enter cavernous sinus,it extends forward inside the cavernous sinus,and at anterior clinoid process it levels up pass through out of the top of the cavernous sinus,it then turns to the medial of the anterior clinoid process and goes upwards.The above-mentioned route closely attach at the lateral wall of sphenoid sinus,and form a pressure track convex to the inside sphenoid sinus.Some part of the internal carotid artery form protuberans inside the sphenoid sinus.Due to the variation of the extent of the gasification,the possibility rates to form the protuberans vary.The same situation happens.Since the sphenoid sinus septum is relatively bent,sometimes it can happen that one side of the sphenoid sinus is bordered by both sides of the internal carotid artery.The thickness of the bone wall of the pressure track of the internal carotid artery inside the sphenoid sinus is about 1.0mm,sometimes it defects naturally.5.5 Sphenopalatine artery and its branchesSphenopalatine artery is the end branches of maxillary artery.It runs up and inward from pterygopalatine fossa,and enters the Nasal cavity at sphenopalatine foramen which locates at slightly upper part of the rear end of middle turbinate.The distance from sphenopalatine foramen to nasal columella root and the lower edge of Sphenoid sinus ostium is about 62mm and 13 mm respectively.The Sphenopalatine artery brances inside the nasal cavity mainly are lateral nasal cavity artery and arteria nasalis posterior septi.The Lateral nasal cavity artery often divides as Upper,middle and lower section of Turbinate artery,respectively entering the corresponding turbinate from the rear end of different turbinate.The arteria nasalis posterior septi is often divided as upper and lower two branches,which turn into the Nasal septum from the lower part of the Anterior sphenoid sinus ostium.The branch close to the sphenoid sinus ostium is called the upper branch of posterior nasal septum artery,the other one relatively farer from the sphenoid sinus ostium is called the lower branch of arteria nasalis posterior septi.The distance from the upper and lower branches of the arteria nasalis posterior septi to the lower end of the sphenoid sinus ostium is about 3.5mm and 6.5mm respectively;the distance to the wall of sphenoid sinus top is 14mm and 16mm;distance to the wall of sphenoid sinus bottom is 11mm and 7.5mm. The main purpose to understand these data:it is necessary to maximize the Anterior wall of sphenoid sinus when conducting endonasal approach,but not to injure the blood vessel and cause bleeding.5.6 Cavernous sinus and intercavernous sinusesCavernous sinus is the pentahedral structure formed by the folding of the subdural from superior orbital fissure to petrous apex beside the sellar region.The left and right side cavernous sinus is connected by front and rear inter-sinus,lower cavernous inter-sinus can locate among subdural at sellar bottom.At the rear back of the sellar,there can be rear cavernous inter-sinus and back sellar sinus,which intersect with both sides cavernous sinus,upper superior petrosal sinus and inferior petrosal sinus.The cavernous inter-sinus relating to the tumor removal sugery under the extended endonasal approach to clivus mainly is:lower intercavernous sinuses, rear intercavernous sinuses,basilar sinus and back sellar sinus.Conclusion1.To understand the clivus region anatomical structure and its adjacent relations and improve the familiarity level of the whole skull bas clivus region,and indirectly improve the safety level of the related surgery.2.To conduct thorough simulating endoscopic surgery on the same group of fixed body head specimens,collect relevant surgical anatomy data,establish surgical landmarks,measure distances of the important anatomy structures at the skull base, can obtain the surgical safety ranges.3.To conduct endoscopic surgery simulation on the same fresh body head specimen and prime pbo reagent to carry out three-dimensional anatomical reconstruction of CT images and MRI head scan,to obtain more experimental data, which is highly meaningful for clinical guidance.4.The experiment demonstrates that the structures of the ventral craniocervical junction can be sufficiently revealed via endoscopic endonasal approach,completely achieve the operation process of endoscopic simulation.It has great meanings to the intensive trainings for clinical doctors before the surgery.5.Clinical application research via anatomy of minimally invasive approach, further demonstrates which structures are critical anatomical structures to determine whether or not the surgery can be successful,and give direct guidance to clinical doctors to carry out surgery via endoscopic endonasal approach.更多还原