经小脑延髓裂入路显微手术切除儿童第四脑室肿瘤

目的 报道经小脑延髓裂入路显微外科手术切除儿童第四脑室肿瘤的临床疗效。方法 采用枕下正中切口、小脑延髓裂入路在手术显微镜下切除第四脑室肿瘤18例。结果 手术治疗18例，其中肿瘤全切除13例，近全切除5例。术后无l例出现小脑性缄默综合征。出现脑积水3例，2例经行侧脑室．腹腔分流后好转，l例因急性梗阻性脑积水死亡。结论 经小脑延髓裂入路，不需切开小脑蚓部，可避免损伤正常小脑组织，应用显微外科技术有助切除第四脑室肿瘤，提高手术疗效。     

第四脑室肿瘤的显微手术治疗

目的探讨第四脑室肿瘤的显微手术方法. 方法 2000年1月～2003年6月我院对29例第四脑室肿瘤采用显微手术治疗,5例因肿瘤侵犯上蚓,瘤体接近皮层部采用小脑蚓部入路,余24例均经小脑延髓裂入路,显微手术切除肿瘤. 结果肿瘤全切除23例,次全切除6例.术后并发症:上消化道出血2例,小脑缄默征1例,第四脑室血肿1例,远隔部位硬膜外血肿1例,呼吸不规则1例.19例随访3～12个月,平均5.5月,肿瘤无复发. 结论术前正确判断肿瘤性质及其基底部所在位置,选择适当的手术入路,熟练掌握第四脑室的显微解剖是手术成功的关键.     

内镜辅助下经外侧壁型小脑延髓裂入路切除第四脑室占位性病变

目的 探讨神经内镜辅助下经外侧壁型小脑延髓裂入路对第四脑室肿瘤的治疗效果.方法 回顾性分析14例第四脑室占位性病变患者的临床资料.所有患者均经外侧壁型小脑延髓裂入路进行手术治疗,对于向导水管深部发展的肿瘤暴露效果欠佳者,采用内镜辅助操作,术中辅以神经电生理监测及术中B超. 结果 病变全切除12例,近全切除1例,大部分切除1例.术后病理诊断:髓母细胞瘤4例,表皮样囊肿3例,室管膜瘤2例,血管母细胞瘤2例,脑膜瘤1例,海绵状血管瘤1例,星形细胞瘤1例.所有患者均恢复正常脑脊液循环通路,术前症状均无明显加重,无面瘫等神经核团损伤相关并发症发生,1例患者术后呼吸微弱给予呼吸机辅助后恢复正常.术后随访3 ～ 28个月,1例死亡,1例髓母细胞瘤复发. 结论 内镜辅助下经外侧壁型小脑延髓裂入路结合电生理监测及超声成像技术,能降低面瘫、听力减退等术后并发症的发生.     

第三脑室肿瘤的显微手术治疗

目的 报道第三脑室肿瘤手术入路及显微手术切除临床效果.方法 回顾分析经显微手术治疗的第三脑室肿瘤58例,其中采用经胼胝体前部入路20例,经终板-翼点联合入路19例,枕部小脑幕入路6例,经皮质-侧脑室入路5例.另有8例应用脑室镜切除肿瘤并行终板造瘘术. 结果 手术全切除37例(63.8%),次全切除14例(24.1%),部分切除7例(8.6%),死亡1例(1.7%).术后症状改善40例(69.0%),症状基本同前11例(19.0%).54例随访5个月～6年,生活自理者51例(94.4%),复发3例(5.6%). 结论 合理的选择手术入路,术中应用显微外科技术妥善处理和保护血管、神经、丘脑等,能较彻底地切除第三脑室肿瘤和提高患者生存质量.     

三脑室手术入路的显微解剖研究

目的:通过研究经前额-纵裂至第三脑室入路的显微解剖结构,为临床切除第三脑室肿瘤提供解剖学依据。方法:15具成人尸头,在显微镜下经前额-纵裂至第三脑室进行解剖,熟悉相关解剖结构。结果:冠矢点位置较为恒定,可作为手术入路的切口定位标志。胼胝体参与侧脑室各个壁的构成;透明隔在中线上分开侧脑室的额角和体部;穹窿是侧脑室壁上围绕在丘脑周围的结构;脉络膜裂是三脑室手术的入路部位。脑室内静脉是手术中重要的解剖标志。大脑深部静脉是手术入路的最大障碍。结论:经前额-纵裂至第三脑室入路经生理间隙进入,对周围结构损伤小,是切除第三脑室肿瘤的较佳人路。     

第三脑室前半部肿瘤经纵裂终板人路

第三脑室肿瘤的手术入路,自Dandy以来,有各种入路,即Dandy的切除右额叶经Monro孔入路,Poppen的切开右额叶经Monro孔入路、Van Wagenen枕叶切开经侧脑室入路,Dandy的经胼胝体松果体部肿瘤摘除,Jamieson的枕下经小脑幕入路,Steln的幕下小脑上入路等.不论做法如何都要避免损伤脑实质,特别是第三脑室周围重要组织,而且极力避免牺牲动静脉,否则术后将产生严重合并症.为了摘除第三脑室肿瘤,无论如何不应损伤第三脑室壁,终板是第三脑室最薄的部分,即视交叉后视     

枕大池重建术治疗Chiari Ⅰ型畸形合并脊髓空洞症

目的 探讨枕大池重建术治疗合并脊髓空洞症的Chiari Ⅰ型畸形操作要点.方法 枕下正中入路,用咬骨钳咬开下项线至枕大孔后缘及寰椎后弓,“Y“形切开硬脑脊膜和蛛网膜.显微镜下对下疝小脑扁桃体弱电流电凝或软脑膜下切除,开放正中孔直至第四脑室底,打通两侧小脑延髓外侧池,切开脊髓中央管口假膜,修补硬脑脊膜及蛛网膜,重建枕大池.结果 36例手术均成功,术中发现30例有脊髓中央管口假膜.术后随访3个月～5年,感觉及肌力均有不同程度的恢复,MRI复查6例脊髓空洞症消失,30例缩小.结论 后颅凹减压、显微镜下开放第四脑室正中孔与两侧小脑延髓外侧池相通、开通脊髓中央管口,是手术治疗Chiari Ⅰ型畸形合并脊髓空洞症的的关键.     

小脑延髓裂入路切除第四脑室肿瘤的护理

目的总结小脑延髓裂入路切除第四脑室肿瘤患者手术前后的护理体会。方法选择我院已实施此手术的19例患者,给予手术前后及时有效的全面护理。结果术后患者头痛、头晕、共济失调、耳鸣等症状多数得到缓解,无并发症发生。结论加强手术前后的全面护理,严密监测病情变化及有效预防并发症的发生,是保障手术成功的必要条件。     

脑干肿瘤的显微手术治疗体会

目的 :总结 1 0例脑干肿瘤进行 1 0次显微手术的经验。方法 :根据肿瘤生长部位及方向不同选择不同的入路。肿瘤位于延脑突向IV脑室者取后颅窝枕下中线开颅 ,切开小脑蚓部 ;突向桥小脑角者选择单侧乳突后入路 ,切除部分小脑。手术在显微镜下直视瘤内小块切除。结果 :8例获得较好的疗效。随访 5个月～ 2年半。 3例恢复工作、学习 ,2例生活自理 ,3例需人照料 ,恢复过程良好 ,术后死亡 2例。结论 :脑干肿瘤积极手术治疗是获得良好疗效的关键 ,MRI是脑干肿瘤首选的检查方法。术后并发症防治至关重要。     

脑干海绵状血管瘤的显微手术治疗

目的 探讨脑干海绵状血管瘤(BSCM)的临床特征及手术治疗的方法与疗效.方法 回顾性分析手术治疗的18例脑干海绵状血管瘤(BSCM)患者,病变位于中脑背侧和背外侧的2例,延髓腹侧和背侧各1例,位于桥脑中脚1例,其余例均位于四脑室底、桥脑背侧.总结影像学特点、手术指征,探讨手术时机、手术入路及手术方法.结果 18例患者均全切除病变,无临床死亡,术前Glasgow Outcom Scale (GOS)评价,5级9例,4级8例,3级1例,无1、2级患者.手术时机多选择于出血后2～4周.手术入路选择:中脑背侧及背外侧者采用经枕下小脑幕切开入路,桥脑中脚选用乙状窦后入路,延髓腹侧病变经远外侧入路,对于四脑室底、桥脑背侧的病变,均采用后颅凹中线入路.术后长期随访按照GOS,显示患者术后恢复5级患者为10例,4级患者7例,3级1例,无2、1级患者.结论 BSCM是可以手术治疗的.严格的掌握手术指征,术前GOS评价,选择合适的手术入路,术中监测和术中精细的手术技巧是手术成功、达到满意疗效的关键.     

Microsurgical and magnetic resonance imaging anatomy of the cerebello-medullary fissure and its application during fourth ventricle surgery.

The cerebellomedullary fissure, the only entrance or exit to the fourth ventricle, is surrounded rostrally by the cerebellar tonsils and the biventral lobules and caudally by the medulla oblongata, the tela choroidea, and the lateral recesses. This fissure is an important route in operations on the fourth ventricle. We studied the microsurgical and magnetic resonance imaging (MRI) anatomy of the fissure by using autopsied normal cerebellum. MRI revealed that the fissure is visible as a slit and is indicated by the enhanced choroid plexus and the flocculus. Oriented by the anatomical information thus obtained, we have surgically treated nine patients with a tumor either in or around the fourth ventricle. Preoperative MRI clearly demonstrated the tumors in relation to the cerebellomedullary fissure. It revealed the precise anatomical location and extension of the tumor, not only its inferior extension but also its lateral one. The MRI findings and microsurgical anatomy of the cerebellomedullary fissure were quite useful for the removal of the tumors in the fourth ventricle.     

Subtonsillar approach to the foramen of Luschka: an anatomic and clinical study

OBJECTIVE: Conventional approaches to tumors of the foramen of Luschka are limited because the foramen is viewed from either the fourth ventricle laterally (transvermian approach) or the cerebellopontine angle medially (suboccipital approach). The definitive approach is subtonsillar, because the foramen of Luschka is actually the end of the natural cleavage plane between the cerebellar tonsil and the medulla. We describe the microsurgical anatomic features of the foramen of Luschka region and the operative technique for the subtonsillar approach to this region. METHODS: In the anatomic study, five formalin-fixed, silicone-injected, cadaveric heads were used. In the clinical study, the records for five patients treated via the subtonsillar approach were examined; several illustrative cases are presented. RESULTS: The foramen of Luschka is formed by the tela choroidea and the rhomboid lip and exists at the lateral end of the cerebellomedullary fissure, which is a natural cleavage plane between the cerebellar tonsil and the medulla. The subtonsillar approach is performed via a suboccipital craniotomy; the patient is positioned in the lateral decubitus position, with the tumor side down. After the cerebellar tonsil is freed from arachnoid adhesions, it can be retracted rostrodorsally from the medulla, to expose the cerebellomedullary fissure. Clinically, the tela choroidea and rhomboid lip are significantly attenuated by tumor expansion. Therefore, by dissecting in a subtonsillar manner around the tumor, one can reach the foramen of Luschka without traversing any neural tissue. CONCLUSION: The subtonsillar approach yields a panoramic view to the foramen of Luschka laterally and up to the middle cerebellar peduncle superiorly. This approach minimizes the distance between the tumor and the surgeon, while maximizing neural preservation. We think this is the definitive approach to this difficult region of the posterior fossa.     

Subtonsillar-transcerebellomedullary approach to lesions involving the fourth ventricle, the cerebellomedullary fissure and the lateral brainstem

We describe the use of the subtonsillar-transcerebellomedullary approach to laterally placed fourth ventricle and brain-stem lesions. The subtonsillar-transcerebellomedullary approach to the fourth ventricle and the lateral brainstem was used in six patients: three patients with tumours of the fourth ventricle and brainstem (two ependymomas and one papillary thyroid carcinoma metastasis), two patients with cavernous angiomas of the brainstem and one patient with a distal posterior inferior cerebellar artery (PICA) aneurysm. The microsurgical anatomy of this approach was studied in five cadaveric head specimens. The tumours and cavernous angiomas were removed and the distal PICA aneurysm was clipped successfully. In all patients the Karnofsky performance scale (KPS) was equal to or better than the preoperative status on follow-up examinations. The anatomical studies also revealed the extensive exposure provided with this approach. The subtonsillar-transcerebellomedullary approach is recommended for lesions occupying the cerebellomedullary fissure, and the lateral aspect of the fourth ventricle.     

Surgical approach to the fourth ventricle cavity through the cerebellomedullary fissure

Lesions of the fourth ventricle represent a challenge to neurosurgeons because of severe deficits that occur following injury to the delicate structures in the ventricle wall and floor. The conventional approach to the fourth ventricle is by splitting the vermis on the suboccipital surface of the cerebellum. In the last 9 years, a series of 21 patients in our clinic underwent microsurgical tumor resection by the unilateral transcerebellomedullary fissure approach. The patients had various pathologies including hemangioblastoma, epidermoid tumor, medulloblastoma, ependymoma, low grade astrocytoma, choroid plexus carcinoma, choroid plexus papilloma, adenocarcinoma in the pons, and cavernoma in the medulla. Total removal was achieved in all but three cases. One death occurred 2 months after surgery due to pulmonary complication. In the follow-up period of 2 months to 5 years, the preoperative symptoms disappeared in all cases except one with a brainstem lesion. By a unilateral transcerebellomedullary fissure approach, it is possible to provide sufficient operative space from aqueduct to obex without splitting the vermis. This approach needs meticulous dissection of the fissure and preservation of the posterior inferior cerebellar artery and its branches.     

Microsurgical anatomy and surgical exposure of the cerebellar peduncles

A better understanding of the surgical anatomy of the cerebellar peduncles in different surgical approaches and their relationship with other neural structures are delineated through cadaveric dissections. We aimed to revisit the surgical anatomy of the cerebellar peduncles to describe their courses along the brain stem and the cerebellum and revise their segmental classification in surgical areas exposed through different approaches. Stepwise fiber microdissection was performed along the cerebellar tentorial and suboccipital surfaces. Multiple surgical approaches in each of the cerebellar peduncles were compared in eight silicone-injected cadaveric whole heads to evaluate the peduncular exposure areas. From a neurosurgical point of view, the middle cerebellar peduncle (MCP) was divided into a proximal cisternal and a distal intracerebellar segments; the inferior cerebellar peduncle (ICP) into a ventricular segment followed by a posterior curve and a subsequent intracerebellar segment; the superior cerebellar peduncle (SCP) into an initial congregated, an intermediate intraventricular, and a distal intramesencephalic segment. Retrosigmoid and anterior petrosectomy approaches exposed the junction of the MCP segments; telovelar, supratonsillar, and lateral ICP approaches each reached different segments of ICP; paramedian supracerebellar infratentorial, suboccipital transtentorial, and combined posterior transpetrosal approaches displayed the predecussation SCP within the cerbellomesencephalic fissure, whereas the telovelar approach revealed the intraventricular SCP within the superolateral recess of the fourth ventricle. Better understanding of the microsurgical anatomy of the cerebellar peduncles in various surgical approaches and their exposure limits constitute the most critical aspect for the prevention of surgical morbidity during surgery in and around the pons and the upper medulla. Our findings help in evaluating radiological data and planning an operative procedure for cerebellar peduncles.

     

Transcerebellomedullary fissure approach with special reference to methods of dissecting the fissure

OBJECT: The purpose of the present study was to refine the transcerebellomedullary fissure approach to the fourth ventricle and to clarify the optimal method of dissecting the fissure to obtain an appropriate operative view without splitting the inferior vermis. METHODS: The authors studied the microsurgical anatomy by using formalin-fixed specimens to determine the most appropriate method of dissecting the cerebellomedullary fissure. While dissecting the spaces around the tonsils and making incisions in the ventricle roof, the procedures used to expose each ventricle wall were studied. Based on their findings, the authors adopted the best approach for use in 19 cases of fourth ventricle tumor. The fissure was further separated into two slit spaces on each side: namely the uvulotonsillar and medullotonsillar spaces. The floor of the fissure was composed of the tela choroidea, inferior medullary velum, and lateral recess, which form the ventricle roof. In this approach, the authors first dissected the spaces around the tonsils and then incised the taenia with or without the posterior margin of the lateral recess. These precise dissections allowed for easy retraction of the tonsil(s) and uvula and provided a sufficient view of the ventricle wall such that the deep aqueductal region and the lateral region around the lateral recess could be seen without splitting the vermis. The dissecting method could be divided into three different types, including extensive (aqueduct), lateral wall, and lateral recess, depending on the location of the ventricle wall and the extent of surgical exposure required. CONCLUSIONS: When the fissure is appropriately and completely opened, the approach provides a sufficient operative view without splitting the vermis. Two key principles of this opening method are sufficient dissection of the spaces around the tonsil(s) and an incision of the appropriate portions of the ventricle roof. The taenia(e) with or without the posterior margin of the lateral recess(es) should be incised.     

Choroid plexus papilloma presenting with cerebrospinal fluid rhinorrhea and otorrhea: case report

A 52-year-old woman presented with right rhinorrhea and right otorrhea manifesting as aural fullness for 2 years caused by a choroid plexus papilloma in the right cerebellomedullary cistern. Computed tomography and magnetic resonance imaging revealed a well defined lobulated mass at the foramen of Luschka, which extended towards the right cerebellomedullary cistern with slight dilation of the ventricular systems. The tumor was totally resected via a right lateral suboccipital approach. Histological examination revealed a choroid plexus papilloma. Postoperative course was uneventful, just after the operation rhinorrhea ceased completely, and hearing of the right ear dramatically improved. Choroid plexus papillomas rarely cause cerebrospinal fluid (CSF) rhinorrhea. Total removal of the tumor resulted in the cessation of CSF leaks.     

Endoscopic telovelar approach to the fourth ventricle: anatomic study

The telovelar approach allows reliable access to the fourth ventricle and avoids the splitting of the vermis and its associated "posterior vermal split syndrome." Our objective was to describe the endoscopic topographical anatomy of the telovelum approach to the fourth ventricle as accessed by the cerebellomedullary corridor. A series of 20 fresh and fixed injected anatomical specimens were used. The endoscopic equipment consisted of rigid endoscopes with different lens angles, while the extradural step required the use of the microscope and/or the exoscope. All the anatomical landmarks and relationships within the fourth ventricle and the cerebellomedullary fissure were identified by means of the endoscopic microscope/exoscope-assisted telovelar approach. In conclusion, we showed that the endoscope is a valid tool to gain an anatomic understanding of the fourth ventricle reached by means of the telovelar approach.