第四脑室肿瘤的显微外科治疗

目的探讨第四脑室肿瘤手术入路和显微手术技巧,以提高第四脑室肿瘤的手术疗效。方法84例第四脑室肿瘤患者,行显微镜下切除肿瘤、后颅窝骨瓣成形及复位术。其中,61例采用正中孔-小脑蚓部入路,19例采用小脑延髓裂入路,4例取正中孔-小脑蚓部与小脑延髓裂联合入路。术前行侧脑室外引流4例,术中行侧脑室-枕大池分流3例,术后行侧脑室外引流术1例。结果本组全切除肿瘤63例(75.0%),次全切除21例(25.0%),无手术死亡病例。术后并发症:上消化道出血6例,小脑缄默症2例,四脑室血肿1例,脑积水1例,颅神经功能障碍1例。随访82例,平均38.4个月,死亡9例。结论术前正确判断肿瘤性质及其基底部所在位置,选择适宜的手术入路,熟练应用显微外科技术,是手术成功治疗的第四脑室肿瘤关键。     

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.     

经岩骨乙状窦前入路显微外科治疗岩斜区肿瘤

目的 探讨岩斜区肿瘤经岩骨乙状窦前入路显微外科治疗的临床疗效。方法 回顾性研究经显微手术治疗的23例岩斜区肿瘤，对肿瘤病理类型、临床和影像学特征、手术入路、手术切除技巧及术后常见并发症的处理进行系统分析。结果 在手术显微镜下肿瘤全切除16例，近全切除4例，大部分切除3例，无手术死亡。结论 经岩骨乙状窦前入路可全切除岩斜区肿瘤。该手术入路对颞叶和小脑牵拉轻，可为岩斜区肿瘤手术切除提供良好的暴露。     

显微外科治疗儿童下丘脑胶质瘤

目的 探讨儿童下丘脑胶质瘤的显微外科治疗方法和术后并发症的处理。方法 根据肿瘤的部位、大小和生长方向进行临床分型，分别采用经肼胝体—弯窿间入路及经纵裂、经额下入路，对21例儿童下丘脑胶质瘤进行显微外科手术治疗。结果 21例儿童下丘脑胶质瘤均经手术和病理证实，肿瘤全切除和近全切除18例，大部分切除3例，术后无死亡病例。主要并发症有下丘脑损伤所致的尿崩、电解质紊乱、高热，手术并发症有硬膜下积液、脑积水、癫痫，均经相应治疗治愈。17例获得随访，16例能正常生活。结论 对儿童下丘脑胶质瘤选择适当的手术入路进行显微外科手术和积极治疗术后并发症是提高疗效的重要方法。     

经胼胝体-穹窿间入路显微手术切除第三脑室肿瘤

目的探讨经胼胝体-穹窿间入路显微手术切除第三脑室肿瘤的方法，并对相应的显微解剖学基础加以讨论。方法经胼胝体-穹窿间入路显微手术切除第三脑室肿瘤12例，其中突入第三脑室颅咽管瘤8例，丘脑内侧型胶质瘤2型，室管膜瘤1例，畸胎瘤1例。结论10例在手术显微镜下肿瘤全切，2例次全切除，全切除率83．3％，其中8例颅咽管瘤中7例全切，术后复查头颅MR未见肿瘤残留及复发。无死亡病例，近期并发症主要为多饮、多尿、电解质紊乱。经处理后1-2周消失。远期并发症为2例脑积水，其中1例半年后行脑室腹腔分流，2例硬膜下积液，3月后自行吸收。全组病例随访最短2个月，最长2年半，1例颅咽管瘤大部切除8月后复发，1例丘脑胶质瘤术后1年复发，其余10例中9例生活正常，1例生活自理。结论经胼胝体-穹窿间入路显微手术切除第三脑室肿瘤系通过胚胎组织残留的组织间隙进入第三脑室，几乎不损伤正常脑组织，手术视野大，直视下操作，可切除第三脑室前、中、后各部位肿瘤，肿瘤全切除率高，并发症少。     

显微手术治疗枕骨大孔区肿瘤28例

目的 探讨枕骨大孔区肿瘤的显微外科手术治疗的临床疗效.方法 根据肿瘤特点,选择正确手术入路.采用枕下后正中入路24例,采用改良的枕颈侧入路4例;在高倍手术显微镜下锐性分离,分辨并保护好重要的血管和神经.瘤内分块切除,减容减压后,牵拉显露被颈髓或延髓遮挡肿瘤部分,逐步切除,尽可能避免牵拉已受压迫的延髓、颈髓和重要的血管神经;肿瘤难以切除或与延髓、上颈髓粘连严重部分,不能强求全部切除.结果 28例中全部切除肿瘤21例(75%),次全切除5例(18%),未能切除2例(7%),只行减压术.术后症状消失11例,症状改善13例,无改善和加重4例.结论 选择合理的手术入路和显微外科技术是切除枕骨大孔区肿瘤获得良好临床效果的重要方法.     

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。     

脑肿瘤

颅咽管肿瘤的手术入路选择及显微手术治疗；经眶上匙孔入路切除鞍结节脑膜瘤；经蝶窦入路显微切除垂体腺瘤；第四脑室肿瘤的诊断和显微外科治疗；大型嗅沟脑膜瘤的显微外科治疗[编者按]     

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.     

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.     

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.     

Ventricular diverticula in obstructive hydrocephalus secondary to tumor growth

OBJECTIVE: The association of ventricular diverticula with intra- and paraventricular tumors causing obstructive hydrocephalus has rarely been reported. METHODS: Records and imaging findings for 57 patients with obstructive hydrocephalus caused by tumors who were treated at our institution were reviewed for the presence of ventricular diverticula. For the anatomic study of ventricular diverticula, data were collected from five cadaveric heads. RESULTS: Ventricular diverticula were identified on magnetic resonance imaging scans in five cases. Diverticula were similarly located in the quadrigeminal cistern but originated from the medial wall of the atrium of the lateral ventricle in three cases and from the superior portion of the fourth ventricle in two cases. Regression of diverticula occurred in all cases after either insertion of a shunt or removal of the obstructing tumor. The cadaveric study suggested that the choroidal fissure and the rostral portion of the superior medullary velum might be the origins of diverticula from the atrium and from the superior portion of the fourth ventricle, respectively. CONCLUSION: Ventricular diverticula should be distinguished from other cystic lesions in the quadrigeminal region. Detection of an ostium of a diverticulum or communication between the cyst and the ventricular system is important for diagnosis.     

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.     

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.     

Clinical, histological, and genetic features of fourth ventricle ependymoma in the elderly

A 71-year-old woman presented with a rare case of geriatric ependymoma originating from the fourth ventricle manifesting as progressive gait and memory disturbance. Imaging studies revealed an extraaxial mass in the fourth ventricle protruding into the right cerebellomedullary cistern, with concomitant obstructive hydrocephalus. Surgery achieved subtotal removal since the tumor tightly adhered to the right vestibular area of the fourth ventricular floor. The histological diagnosis was ependymoma, which was also confirmed by comparative genetic hybridization. Although she developed severe laryngeal edema and worsening of the hydrocephalus postoperatively which required additional treatment, she recovered with residual mild gait disturbance, and was transferred to a rehabilitation facility. Fourth ventricle ependymoma in the elderly is rare. Comparative genetic hybridization may be important in the diagnosis of geriatric ependymoma and in the choice for adjuvant therapy as well as in estimating the prognosis for patients with rare types of ependymoma.     

Telovelar approach to the fourth ventricle: operative findings and results in 16 cases

Summary Background. The cerebellomedullary fissure as a corridor for exposure of the fourth ventricle without vermian splitting is enjoying increasing application as a technique for exposure, to avoid the complications related to vermian splitting. The purpose of this study is to describe the operative findings and the results in 16 fourth ventricular tumours removed via telovelar approach. The impact of the pathological nature of the lesion on the degree of tumour removal is also discussed.Methods. Telovelar approach to the fourth ventricle was used in 16 consecutive patients. The charts were reviewed retrospectively. The pathological changes in the tela choroidea and inferior medullary velum, degree of tumour removal, and the clinical outcome are described.Findings. The tela choroidea was thinned out and streched over the tumour surface in 10 cases (large tumours). In epidermoid and dermoid cysts (3 cases), the tela choroidea was amalgamated with the tumour capsule. The inferior medullary velum was infiltrated by the tumour and was not detected as a separate layer in 6 cases (3 cases vermian astrocytomas and 3 cases medulloblastomas). The inferior medullary velum was thinned out and stretched as a neural tissue sheet over the tumour surface in 10 cases (4 ependymomas, 2 meningiomas, 2 epidermoids, one dermoid and one choroid plexus papilloma). Total removal was achieved in 11 out of 16 patients (68.75%). Subtotal removal was achieved in the remaining patients (31.25%); three ependymomas, one medulloblastoma, and one anaplastic astrocytoma. Cerebellar mutism was not observed in any patient and there was no mortality.Interpretation. Despite the panoramic view provided by the telovelar approach, the pathological nature of the lesion and vital neural tissue infiltration are limiting factors for total tumour removal. Total removal of tumours focally attached to critical areas in the fourth ventricle should not be attempted at the expense of patients morbidity and mortality. To achieve optimum outcome, near total excision is acceptable in cases where complete removal may endanger function or life.