【作者】 刘晓东；

【导师】 徐启武； 车晓明； 张明广；

【作者基本信息】 复旦大学 ， 外科学， 2009， 博士

【摘要】 第一部分三叉神经的显微解剖研究目的：对三叉神经颅内行程的各段结构进行解剖学研究，探索其解剖特征，为进一步研究Meckel’s腔的解剖结构及临床应用提供解剖学基础。方法：成人头颅湿标本共15例，经颈内动脉、椎动脉和颈内静脉无压力条件下分别灌入红色和蓝色乳胶。头颅标本均沿眉弓上缘至枕外粗隆上1cm水平锯开颅盖骨，自大脑脚水平切除大脑，显露三叉神经自出入脑干处到经颅底出颅的整个行程，显微镜下观察并测量颅内各段三叉神经的长短距离。测量数据采用SPSS13.0软件描述统计量分析，结果以均数±标准差((?)±s)表示。结果：脑池段三叉神经长17.64±1.93mm，三叉神经节前后长15.48±0.88mm，三叉神经节内外宽12.41±1.31mm，三叉神经厚度2.77±0.69mm，Meckel’s腔段内V1长23.40±2.20mm，V2长12.06±1.38mm，V3长5.67±0.70mm。三叉神经脑池段位于后颅窝桥前池的蛛网膜下腔中。蛛网膜随三叉神经根进入Meckel’s腔，延至三叉神经节中部稍前，之后两层蛛网膜与包绕神经节的结缔组织相互融合，两层蛛网膜之间的间隙即构成三叉神经池。Meckel’s腔段的三叉神经根部分以及三叉神经节起始段也位于Meckel’s腔中的蛛网膜下腔即三叉神经池中。三叉神经节远侧段以及其三个分支颅内段位于Meckel’s腔硬膜夹层中。三叉神经节为半月型，整体上呈神经丛样的外观，其由浓密的神经纤维组成网络样结构，其中有的纤维相互交叉，有的彼此桥连，有的则不间断直接进入末端分支神经。运动根通常起自感觉根的背侧，在Meckel’s腔内逐渐移行到三叉神经节的腹内侧，汇入下颌神经或与之相伴出卵圆孔。位于脑池段三叉神经根周围的颅底血管与三叉神经根出入脑干处关系最密切的是小脑上动脉，30侧标本中有1例小脑上动脉于分出腹背侧处的主干分叉处压迫三叉神经根背侧，3例小脑上动脉主干与三叉神经根背侧密切接触，1例小脑上动脉腹侧分支与三叉神经根密切接触，另外尚有1例小脑前下动脉与三叉神经根密切接触。30侧标本中有1侧发现起源于脑池段三叉神经感觉根的原发三叉神经鞘瘤。结论：三叉神经节为由浓密的相互交叉、彼此桥连抑或单根直线走行的神经纤维组成网络样结构。运动根通常位于三叉神经节的腹内侧，汇入下颌神经或与之相伴出卵圆孔。随三叉神经根进入Meckel’s腔的两层蛛网膜与包绕神经节的结缔组织相互融合，两层蛛网膜之间的间隙即构成三叉神经池。三叉神经根部与小脑上动脉等血管结构关系密切，是三叉神经痛的重要原因之一。第二部分Meckel’s腔的显微解剖研究目的：研究颞骨岩尖Meckel’s腔的解剖形态、位置以及毗邻结构特点，为岩斜区经颞底经天幕手术入路提供临床帮助。方法：成人头颅湿标本共15例。经颈内动脉、椎动脉和颈内静脉无压力条件下分别灌入红色和蓝色乳胶。同第一部分沿眉弓上缘至枕外粗隆上1cm水平锯开颅盖骨，自大脑脚水平切除大脑，暴露Meckel’s腔和三叉神经，显微镜下观察并测量Meckel’s腔内外长度(自岩上嵴三叉神经根中点至上下壁在外侧的附着线的垂直距离)、前后宽度(长的中垂线)和上下厚度(过长宽交点并与长宽垂直)，以及三叉神经孔至滑车神经入天幕缘孔距离、至Dorello’s管开口距离、至内听道开口距离和至三叉神经出脑干处距离。测量数据采用SPSS13.0软件描述统计量分析，结果以均数±标准差((?)±s)表示。结果：Meckel’s腔位于中颅底颞骨岩尖上外侧，海绵窦后外下方，为后颅窝向中颅窝后内侧突入的硬脑膜凹陷，其包括上、下、前、后壁及内、外侧壁六个面。腔内包含有三叉神经池、三叉神经节及其分支等结构。本组实验测得Meckel’s腔长14.47±1.05mm，宽15.10±1.30mm，厚5.03±0.50mm。Meckel’s腔后壁不完整，有三叉神经孔与桥前池相通。内侧壁是Meckel’s腔各壁中较薄的结构，其前部与颈内动脉海绵窦段后升部和滑车神经相邻，后部与颞骨岩尖部岩蝶韧带相贴，毗邻Dorello’s管，展神经走行于岩蝶韧带的内下方。下壁前方隔岩舌韧带与颈内动脉破裂孔段相邻，后方为颞骨岩尖三叉神经压迹，颈内动脉在岩舌韧带上缘由破裂孔段移行为海绵窦段。Meckel’s腔外侧壁与颅中窝内侧壁硬脑膜相续，毗邻颞叶脑组织。后壁三叉神经孔至滑车神经入天幕缘孔距离5.12±1.01mm，至Dorello’s管开口距离9.32±0.98mm，至内听道开口距离15.24±1.43mm，至三叉神经出脑干处距离11.21±1.86mm。Meckel’s腔后上方有岩上窦，后下方有岩下窦。Meckel’s腔外侧缘下方深面有岩浅大神经，是暴露颈内动脉岩骨段水平部的重要标志。圆孔、卵圆孔和棘孔依次排列于Meckel’s腔外侧中颅底，棘孔后外侧的弓状隆起是中颅窝重要的骨性解剖标志。结论：Meckel’s腔通过三叉神经孔、眶上裂、圆孔和卵圆孔分别与后颅窝桥前池、眼眶、翼腭窝和颞下窝相沟通。Meckel’s腔内侧壁的硬膜层较为菲薄，并直接与海绵窦静脉腔隙相邻，是肿瘤侵入海绵窦的薄弱点之一。PSL和PLL是Meckel’s腔内侧识别展神经和颈内动脉的重要标志。第三部分三叉神经鞘瘤的临床特征及手术治疗研究目的：三叉神经鞘瘤是颅底少见良性肿瘤，探讨这一少见颅底肿瘤的临床特征和手术治疗经验。方法：收集从2003年至2007年收治的经手术和病理确诊的84例三叉神经鞘瘤，其中5例为复发病例，2例为γ刀放疗未控制病例。结果：女性40例，男性44例(平均年龄43岁)。其中24例中颅窝型，9例后颅窝型，45例中后颅窝哑铃型，6例颅外型。临床表现中最常见的为三叉神经受累表现，早期多为头痛、面部麻木、角膜反射消失，其次为运动麻痹和三叉神经痛。43例患者行CT扫描，其中16例患者的CT骨窗扫描可见三叉神经鞘瘤引起的典型的岩尖骨质破坏。所有患者术前均常规行MRI平扫和增强扫描，三叉神经鞘瘤在MRI T1加权像上为等信号或轻度低信号。在T2加权像上呈高低混杂信号，高信号为囊变成分，低信号为实质部分。增强扫描中肿瘤实质部分有明显强化，囊性部分多呈环形强化。8例患者行CTA或MRA检查，可见中颅窝部分肿瘤引起大脑中动脉和颈内动脉海绵窦段的推挤移位，后颅窝部分肿瘤引起后交通动脉，大脑后动脉，小脑上动脉以及基底动脉移位。8例患者应用了Dextroscope虚拟现实技术进行术前计划准备，对肿瘤和周围的重要神经血管结构进行3D重建。13例应用额颞入路，30例应用额颞颧弓入路，18例应用额颞眶颧弓入路，7例颞下入路，14例乙状窦后入路。63例(75％)患者中肿瘤获得全切，3例(3.6％)患者近全切除，18例(21.4％)患者次全切除。未能全切的主要原因有脑干粘连(9／21)，重要血管粘连(5／21)，暴露不充分(3／21)，海绵窦受累(1／21)。没有死亡病例。术后并发症主要有脑膜炎6例，脑积水3例，展神经麻痹3例，硬膜外血肿2例，脑脊液漏1例。术后65例患者随访10到60个月(平均25个月)，没有发现肿瘤复发。结论：典型的影像学表现有助于三叉神经鞘瘤的诊断。CT扫描骨窗位上常有岩尖骨质破坏表现，MRI上可见典型的岩尖占位、哑铃型形态、Meckel腔受累并扩大，多半有单发或多发的囊变改变。额颞入路、额颞颧弓入路、额颞—眶—颧弓入路、颞下入路以及乙状窦后入路等多种手术方法可以用于切除三叉神经鞘瘤，并获得良好效果。Dextroscope虚拟现实技术进行术前计划准备，可以从不同角度提供详细的个体解剖信息的特点，有助于我们设计个性化的手术入路。γ刀治疗可以作为三叉神经鞘瘤手术治疗的补充或不宜手术治疗时应用。第四部分颞底经天幕入路切除哑铃型三叉神经鞘瘤目的：在研究Meckel’s腔显微结构的基础上，临床应用颞底经天幕入路切除哑铃型三叉神经鞘瘤，探讨这一手术入路在切除此类型肿瘤的优缺点以及Meckel’s腔在此手术入路中的临床意义。方法：从2003年至2007年间收治骑跨中后颅窝的哑铃型三叉神经鞘瘤患者6例，所有患者均接受颞底经天幕入路手术治疗。结果：所有6例哑铃型三叉神经鞘瘤患者，肿瘤均获得全切，切除率100％。术后患者无严重并发症出现。1例患者术后同侧面部麻木未能缓解，1例患者短暂展神经麻痹。无其他颅神经麻痹及肢体活动障碍出现。术后6例患者获得随访，随访时间从18-60个月不等，平均37个月，期间患者生活正常，复查肿瘤无复发。结论：颞底经天幕入路已成为我们处理哑铃型三叉神经鞘瘤的标准手术入路之一，它可以同时进海绵窦外侧壁的硬膜间隙、Meckel’s腔以及后颅窝。我们认为该入路操作容易、创伤小，具有显露满意，能在直视下或较为直视下切除Meckel’s腔、海绵窦内及桥小脑角肿瘤；至后颅窝肿瘤距离近，有利于减少手术损伤；牵开颞枕部脑组织较为容易，显露充分；可原位缝合硬脑膜，发生脑积液漏的几率低；不必磨除岩骨，颅底缺损小，术毕不需特别重建的优点。打开Meckel’s腔，切开天幕、三叉神经孔进入后颅窝，可以将中后颅窝的肿瘤当做一个整体对待，全程追踪三叉神经的走行，更好保护三叉神经，同时可清楚了解周围神经血管结构，以较低的伤残率全切肿瘤。更多还原

【Abstract】 PARTⅠMicrosurgical Anatomy of Trigeminal NerveObjective: To explore the intracranial course of trigeminal nerve, and study thecharacter of the anatomical structure of trigeminal nerve, and gain the orientationregarding with Meckel’s cave.Meterials and methods: Fifteen cadaver heads for a total of 30 sides were examined,using×2 to×40 magnification after perfusing the arteries and veins with colored latex.The skull was opened and the brain was carefully removed to expose the entire skullbase. The intracranial course of trigeminal nerve was exposed. The nerve wasmeasured under micrcoscope.Results: The length of the cisternal segment of the trigeminal nerve was17.64±1.93mm.The length, width and thickness of trigeminal ganglion were15.48±0.88mm, 12.41±1.31mm and 2.77±0.69mm. The length of V1 in Meckel’scave was 23.40±2.20mm, V2 was 12.06±1.38mm, V3 was 5.67±0.70mm.Thecisternal segment of the trigeminal nerve located in the prepontine cistern. Thetrigeminal nerve passes from the posterior fossa over the trigeminal impression of thepetrous apex between the periosteal and meningeal layers of middle fossa dura,carrying with it arachnoid and dura propria from the posterior fossa. The subarachnoidspace within Meckel’s cave is behind the GG and is the actual space that constitutesthe trigeminal cistern. The gasserian ganglion was semilunar-shaped. Some rootlets inMeckel’s cave cross each other; however, some are connected to each other and somecontinue without interruption, without crossing a rootlet and without making aconnection with a rootlet. This semilunar network has a plexiform appearance. Motorrootlets arose rostral to the sensory root, and followed or joined with V3 in theMeckel’s cave. The most common finding at a vascular decompression operation for trigeminal neuralgia is a segment of the SCA compressing the trigeminal nerve. In our30 specimens, we found one SCA compressed the nerve, and 3 arteries and 1 branchcontacted with the nerve tightly. We also found 1 AICA contacted with the nervetightly. In 30 specimens, there was one trigeminal schwannoma was found.±Conclusions: The gasserian ganglion is a semilunar-shaped network which has aplexiform appearance. The trigeminal nerve enters, carrying with it arachnoid anddura propria from the posterior fossa. The subarachnoid space within Meckel’s cave isis the actual space that constitutes the trigeminal cistern. Most cases of trigeminalneuralgia were thought to be the result of a pulsating blood vessel compressing thetrigeminal nerve at the root entry zone. The offending vessel was most commonly thesuperior cerebellar artery(SCA).Trigeminal schwannoma was the most commonlytumor arising from the nerve.PARTⅡMicrosurgical Anatomy of Meckel’s CaveObjective: The anatomical shape, location and adjacent structures of the Meckel’scave were investigated, in order to gain the orientation regarding with temporal basetranstrntorial approach.Materials and methods: Fifteen cadaver heads for a total of 30 sides were examined,using×2 to×40 magnification after perfusing the arteries and veins with colored latex.The skull was opened and the brain was carefully removed to expose the entire skullbase. The Meckel’s cave was exposed. The length, width and thickness of the cavewere measured under micrcoscope. The distances between the porus trigeminus andnear structures were also measured.Results: Meckel’s cave was a dural recess extending from the posterior fossa to theposteromedial portion of the middle cranial fossa, the trigeminal ganglion and trigeminal cistern in it. Meckel’s cave was constituted by superior wall, inferior wall,anterior wall, posterior wall, medial wall and lateral wall. The length, width andthickness of the Meckel’s cave were 14.47±1.05mm, 15.10±1.30mm, 5.03±0.50mm.The porus trigeminus is an oval-shaped opening of Meckel’s cave in posterior wallthat communicates with the posterior fossa. The medial wall of Meckel’s cave wasthinness and close to cavernous sinus and Dorell’s canal, and many significant nervesand vessels near it. The dural sleeve of the abducens nerve was located below the PSL,and the PLL invariably surrounded part of the dorsal and lateral walls of the lacerumsegment of the internal carotid artery (ICA), just under the anteroinferior portion ofthe anteromedial wall of Meckel’s cave in all specimens. The distance between theporus trigeminus and the entrance site of trochlear nerve in the middle incisural space,the entrance site of abducent nerve in Dorello’s canal, the entrance site of facial nervein internal auditory canal and the trigeminal nerve root entry zone were5.12±1.01mm, 9.32±0.98mm, 15.24±1.43mm and 11.21±1.86mm. There were thesuperior petrosal sinus and inferior petrosal sinus in posterior of Meckel’s cave. Thegreater petrosal nerve(GSPN) crossed anterolaterally to the Meckel’s cave, and it waslandmark to identify the lacerum segment of the ICA. The foramen rotundum, theforamen ovale and the foramen spinosum arranged laterally to the Meckel’s cave inthe middle cranial fossa. The arcuate eminence located behind the foramenspinosum, which is the important landmark in the middle cranial fossa.Conclusion: The Meckel’s cave cound communicate with the posterior craninal fossa,posterior part of fossa orbitalis, fossa pterygopalatina and fossa infratemporalis by theporus trigeminus, the superior orbital fissure, The foramen rotundum and the foramenovale. The medial wall of Meckel’s cave was thinness, and which adjacent to thecavernous sinus and is the weak points of the meningeal wall for tumor invasion to orfrom the cavernous sinus. The petrosphenoidal ligament (PSL) and the petrolingualligament (PLL) are valuable anatomical landmarks for identifying the ICA andabducent nerve in this region. PARTⅢThe Study of The Clinical Features and Surgical Therapy of TrigeminalNeurinomasObjective: Trigeminal neurinomas are the second most common intracranialneurinomas next to the vestibular neurinomas.Methods: 84 patients with trigeminal neurinomas were treated between 2003 and2007, including 5 recurrent patients and 2 patients who failed toγradiotheraphy.Results: There were 40 women and 44 men (mean age 43 years). There were 24 typeA, 9 type B, 45 type C, and 6 type D tumors. Patients with neurofibromatosis Type 2were excluded. Among the 84 patients, five were recurrent, two were failure toGamma knife radiotherapy. These cases accounted for 0.6% of intracranial tumors and9.2% of intracranial neurinomas operated in our department during the same period.The most common early symptoms were headache (36/84) and numbness of theipsilateral hemiface (30/84). Erosion of the petrous apex and neighboring bonestructures was noted on CT scan in 16 of 43 patients. On T1-weighted sequences, thetumor appeared isointense or slightly hypointense. On T2-weighted sequences, thesetumors were either high signal or mixed with high and low signal. After contrastmedium, the solid part showed either homogeneous enhancement, and the capsulewall showed rim enhancement. Dextroscope virtual reality technology was used forpreoperative planning in recent 8 cases. In this series, the frontotemporal approachwas performed in 13 cases, the frontotemporal zygomatic approach in 30 cases, thefrontotemporal orbitozygomic approach in 18 cases, the subtemporal approach in 7cases, the retrosigmoid approach in 14 cases, the transmandibular approach in 1 case,and the combined frontotemporal-retrosigmoid method in 1 case. Gross total resectionwas achieved in 63 (75%) patients, near-total resection was achieved in 3 (3.6%)patients, and subtotal cytoreductive resection was achieved in 18 (21.4%) patients.The impediments to complete removal were adherent to the brainstem (9/21),adherent to important vascular structure (6/21), inadequate exposure(4/21), cavernous sinus involvement(2/21). Postoperative complications included meningitis in 6patients, hydrocephalus in 3 patients, epidural hematoma in 2 patients, cerebrospinalfluid (CSF) leak in 1 patient. The follow-up period ranged from 10 to 60 months(average 25 months) in 65 patients. No tumor recurrence was observed in follow-uppatients.Conclusion: The typical CT and MRI findings are contribute to the diagnoses of thetrigeminal neurinomas. The frontotemporal approach with zygomatic ororbitozygomic osteotomy or subtemporal approach could offer excellent exposure ofthe middle fossa and access to the posterior fossa. The trigeminal neurinomas couldbe removed by the frontotemporal approach with or without zygomatic ororbitozygomic osteotomy, the subtemporal approach, the retrosigmoid approach, et al.Dextroscope virtual reality technology was a very useful tool to identify surgical andanatomic nuances and enhance preoperative planning in trigeminal neurinomasresection.PARTⅣTemporal Base Transtentorial Approach to The Dumbbell-Shaped TrigeminalSchwannomaObjective: To investigate temporal base transtentorial approach for thedumbbell-shaped trigeminal schwannoma, study the clinical significance of theMeckel’s cave.Methods: The clinical data of 6 dumbbell-shaped trigeminal schwannoma, operatedwith the temporal base transtentorial approach from 2003 to 2007, were reviewed.Results: There were no severe postoperative complications in the 6 patients. Thenumbness of the ipsilateral hemiface in 1 patient could not recovery. The abducensnerve palsy in 1 patient was short-lived. No additional cranial nerves paralysis werenoticed postoperatively. There was no surgical mortality. The follow-up period ranged from 18 to 60 months (average 37 months) in 6 patients. No tumor recurrence wasobserved in follow-up patients.Conclusion: The temporal base transtentorial approach has become our standardapproach to the dumbbell-shaped trigeminal schwannoma. Advantages of the surgicalapproaches are wide operating field to the middle fossa, CS, Meckel cave, andtrigeminal pore; unnecessary to drill the petrous apex for resection of tumors in theCPA; safely removing the tumor in the posterior cranial fossa and the CPA underdirect visualization; no need special reconstruction because of limited bone removalof the middle cranial base. Open the trigeminal pore or tentorial incisura after theentrance site of trochlear nerve in the middle incisural space, the structures in CPAcould be showed clearly.更多还原