Surgical Management of PICA Aneurysm and Incidental Facial Nerve Schwannoma: Case Report.

We report a patient with a posterior inferior cerebellar artery (PICA) aneurysm and an incidental facial nerve schwannoma at the cerebellopontine angle (CPA). A 46-year-old woman presented with the sudden onset of a severe headache, nausea, and vomiting. She had no other abnormal neurological symptoms and signs. Computed tomography (CT) showed hemorrhage in the fourth ventricle. Cerebral angiography demonstrated an aneurysm arising from the tonsillomedullary segment of the left PICA. A facial nerve schwannoma was incidentally found as the aneurysm was being clipped. The aneurysm was clipped via a left transcondylar approach. Subsequently, the schwannoma (2 x 3 x 2 mm) was resected from the facial nerve fascicles, and the facial nerve was preserved. Postoperatively, the patient developed mild to moderate dysfunction of the facial nerve (House-Brackmann grade III [H-B III]) but her hearing was intact. Both a facial nerve schwannoma involving the CPA and an aneurysm involving the PICA can be managed through the transcondylar approach. An asymptomatic facial nerve schwannoma can be resected safely with minimal facial nerve dysfunction.     

经单侧半椎板切除髓内海绵状血管瘤

目的探讨脊髓髓内海绵状血管瘤的出血性损伤风险、临床特征以及经单侧半椎板切除髓内海绵状血管瘤的手术技巧。方法回顾性分析11例髓内海绵状血管瘤病人的病历资料。均经单侧半椎板切除肿瘤。采用统计学分析，在性别分布、平均年龄、年出血率等方面与同期颅内（145例）、脑干（61例）海绵状血管瘤进行比较。术前Frankel分级D级8例，C级2例，A级1例。结果本组女性7例，男性4例．女性与男性之比高于颅内（80：65）和脑干（33：28）海绵状血管瘤；年出血率为2．8％／病人，稍低于颅内（3．3％）和脑干（3．1％）海绵状血管瘤。病变均获全切：术后随访期内8例神经系统症状改善（Frankel分级D级升到E级6例，C级升到D级2例）．3例临床症状无变化。结论脊髓髓内海绵状血管瘤应全切以防复发和再出血；选择微侵袭的半椎板入路，以及术中采用体感诱发电位监护．是取得满意结果、预防附加损伤的关键．     

Is preoperative high-resolution magnetic resonance imaging accurate in predicting neurovascular compression in patients with trigeminal neuralgia?

High-resolution magnetic resonance imaging (HR-MRI) using three-dimensional fast imaging employing steady-state acquisition (3D-FIESTA) and double-dose contrast-enhanced three-dimensional fast spoiled gradient echo (3D-FSPGR) sequences is considered to be a useful tool in detecting neurovascular compression in patients with trigeminal neuralgia. The purpose of this study was to analyze the accuracy and preoperative diagnostic value of these high-resolution imaging techniques in patients with trigeminal neuralgia, in a single-blind study. The preoperative MRI images of 21 consecutive patients were matched to one neuroradiologist, who was blind as to which side exhibited the symptoms. The images and post-processing multiplanar reconstructions were compared with the video-documented operative observations. HR-MRI using only 3D-FSPGR sequences demonstrated neurovascular compression in accordance with the intraoperative finding in 11 patients (52.4%). In the subgroup where, additionally, 3D-FIESTA sequences were available, neurovascular compression was in accordance with the intraoperative finding in 71.4% (n = 7). High-resolution magnetic resonance imaging using double-dose contrast-enhanced 3D-FSPGR and 3D-FIESTA sequences is currently not sufficient enough to make an accurate prediction of neurovascular compression in a single-blind setting. These 3D imaging techniques currently provide only limited information, and one should consider their use carefully when identifying patients with trigeminal neuralgia from operation until image quality is improved by superior image resolution that can accurately discriminate vessels surrounding the trigeminal root entry zone.     

Immunohistochemical study in dural arteriovenous fistula and possible role of ephrin-B2 for development of dural arteriovenous fistula

Background Although there were several clinical and experimental studies discussing the pathogenesis of dural arteriovenous fistula (DAVF), the pathological process leading to intracranial DAVF so far remains unknown. In this study, we investigated the expression of vascular growth factors in order to elucidate the possible role of these factors for the development of DAVF and to study the biological activity of this uncommon lesion.Methods We examined the histological features, proliferative and angiogenic capacities of the tissue specimens obtained from 6 patients who underwent surgery at our institution. Immunohistochemical staining for vascular endothelial growth factor (VEGF), its receptors FIk-1 and Fit-1, ephrin-B2, MIB-1 and proliferating cell nuclear antigen (PCNA) was performed using standard immunohistochemical techniques.Results A positive immunostaining was found for all antibodies studied except MIB-1, whereas nuclear endothelial expression of PCNA was observed in only 3/6 cases. VEGF stained positive in all of the available specimens (6/6). FIk-1 showed a positive immunoreaction in only 2/6 cases and Fit-1 in 4/6 cases. Ephrin-B2 was expressed in the majority (5/6) of the cases.Conclusions These results support the hypothesis that DAVFs might be acquired dynamic vascular malformations with low biological activity. Vascular growth factors like VEGF and ephrin-B2 might play a pivotal role in the formation of DAVF.     

Biological activity of paediatric cerebral cavernomas: an immunohistochemical study of 28 patients

Objective According to the hypothesis that paediatric cerebral cavernomas may have different biological activity compared to adult cavernomas, immunohistochemical analysis was used to elucidate the biological nature of paediatric cavernomas.Patients and methods We examined the histological features and the proliferative and angiogenic capacity of the tissue specimens acquired from 28 paediatric patients. Normal paediatric brain tissues obtained from paediatric autopsy cases were used as a control group. The proliferative activity of the endothelium and the neoangiogenetic capacity were investigated by immunohistochemistry for proliferating cell nuclear antigen (PCNA), Ki-67 epitope (MIB-1), Flk-1 receptor, vascular endothelial growth factor (VEGF), hypoxia-inducible factor (HIF)-1 α, and endoglin antibody, respectively. Afterwards, the results of the paediatric lesions were analysed and compared with the correspondent values of previously reported immunohistochemical analysis in adult cavernomas.Results Positive immunostaining of VEGF was detected significantly less in paediatric cavernomas compared to adult cases (p<0.05). In contrast, endoglin, a protein that is upregulated during an increased vascular shear stress, was expressed more often in paediatric cavernomas (p<0.05). Neither the expression of the PCNA nor the expression of the HIF-1α was found significantly different between paediatric and adult cavernomas. However, the positive immunoreaction for MIB-1 occurred more often in the paediatric cases (p<0.05).Conclusions The immunohistochemical study indicates that paediatric cavernomas are dynamic lesions. The VEGF/Flk-1 associated neoangiogenesis may play a minor role for the biology of paediatric cavernomas, while endoglin seems to act more prominently than previously thought, particularly for the biology of paediatric cavernomas.     

Comparative experimental study of argon plasma and bipolar coagulation techniques

Summary Background. Argon plasma coagulation (APC) is based on the principle of ionised argon creating conductive plasma between an activating electrode and tissue surface and is used as an effective alternative coagulation technique in various surgical disciplines. This trial aims to compare thermal injury in rat brain caused by APC and conventional bipolar coagulation technique. Methods. A controlled study design with constant power setting and application time was established. Twenty rats were randomised into the APC and bipolar groups. Each group of ten rats had 20 treated lesions. Early and late histopathological changes, as well as maximum extent of the lesion after 48 hours (h) and 12 days were studied in overall 20 lesions. Findings. Although the maximum depth of the lesions was different in APC (2.2 mm) and bipolar (1.8 mm) groups after 48 h, this did not achieve statistical significance (p = 0.151). The superficially coagulated area was significantly larger after APC compared with the bipolar technique at the 48 h time point (p = 0.032). After twelve days there were no differences in penetration depth (p = 0.310) or coagulated area (p = 0.222). Conclusion. Tissue defects after APC application on rat brains were comparable to conventional bipolar technique in this trial. The results suggest that argon plasma coagulation (APC) is an effective coagulation technique.     

经菱形窝切除脑干海绵状血管瘤

目的探讨28例经菱形窝入路切除的脑干海绵状血管瘤的适应证、手术技巧及术中注意点。方法术中采取坐位,枕下正中开颅,广泛打开小脑延髓裂;在脑干表面有色素沉淀或膨隆处,或在B超、导航引导、术中颅神经监护下切开脑干,病变暴露后清除血肿,然后切除病变,保留含铁血黄素沉淀的胶质组织。结果28例中有21例位于桥脑;术中发现脑干表面有含铁血黄素沉淀21例,其中脑干表面膨隆9例;所有病变位于脑干背侧;随访期间:症状和体征较术前改善的19例,保持术前水平的5例,加重、出现新的颅神经症状、或其他神经功能障碍(共济失调、运动障碍、感觉障碍)共4例。MRI随访未见病变残留或复发。结论经菱形窝入路主要适于桥脑部、且位于背侧的海绵状血管瘤;脑干表面的含铁血黄素沉淀和(或)膨隆是脑干的安全进入区,术中结合神经电生理监测、B超以及导航是手术成功的关键;术中尽可能全切病变,但保留含铁血黄素沉淀的胶质组织。     

The role of neuroendoscopy in the management of solid or solid-cystic intra- and periventricular tumours

Objects The purpose of this study was to describe the surgical strategies of neuroendoscopic treatment in patients with solid or solid-cystic peri- and intraventricular tumours. Analysis of the postoperative histopathology and complication of neuroendoscopic interventions was also performed. Background A number of intracranial tumours do not ultimately require aggressive surgical intervention. Either definite or palliative treatment for the intra- and periventricular lesions could be accomplished using various neuroendoscopic techniques, depending on the histopathological diagnosis and aim of therapeutic intervention. Materials and methods Between 1994 and 2004, 46 patients with newly diagnosed solid or solid-cystic peri- and intraventricular tumours underwent neuroendoscopic procedures Twenty patients had associated hydrocephalus requiring the cerebrospinal fluid diversion procedures. Since 1997, neuronavigation has been applied to selected cases. Results Obstructive hydrocephalus was treated sufficiently by endoscopic third ventriculostomy or endoscopic stent placement. Partial or total extirpation of solid tumour was achieved in four cases. The majority of pathological examinations revealed astrocytoma (23), craniopharygioma (7) and metastasis (2). Subsequent mode of treatment such as chemotherapy, radiation therapy or microscopic surgery was determined according to the pathological findings. There were three transient morbidities and one permanent deficit, but no operative mortality. Conclusion Transventricular endoscopic approach is an effective and reliable alternative treatment of newly diagnosed peri- and intraventricular lesions. Neuroendocopic procedures offer the opportunity to combine tumour biopsy and treatment of hydrocephalus. In selected patients, partial or total tumour removal could be performed. Presented at the Third World Conference of the International Study Group on Neuroendoscopy (ISGNE), Marburg, Germany, 15–18 June 2005.     

Immunohistochemical study in dural arteriovenous fistulas and possible role of local hypoxia for the de novo formation of dural arteriovenous fistulas

OBJECTIVE: Although previous clinical and experimental studies investigated the pathogenesis of dural arteriovenous fistulas (DAVFs), the biological process leading to intracranial DAVFs so far remains unknown. In this study, we investigated the expression of vascular growth factors in order to elucidate the possible role of these factors in the development of DAVFs. METHODS: We examined the histological features, proliferative and angiogenic capacities of the tissue specimens obtained from eight patients who underwent surgery at our institution. Immunohistochemical staining for vascular endothelial growth factor (VEGF), its receptors Flk-1 and Flt-1, transforming growth factor alpha (TGFalpha), basic fibroblast growth factor (bFGF), hypoxia inducible factor 1alpha (Hif-1alpha), MIB-1 and proliferating cell nuclear antigen (PCNA) was performed using standard immunohistochemical techniques. RESULTS: A positive immunostaining was found for all antibodies studied except MIB-1, whereas nuclear endothelial expression of PCNA was observed in only 3/8 cases. Hif-1alpha and VEGF stained positive in all of the available specimens (7/7). Flk-1 showed a positive immunoreaction in only 2/8 cases and Flt-1 in 5/7 cases. TGFalpha and bFGF were expressed in the majority (6/8) of cases. CONCLUSION: These results indicate the possible role of local tissue hypoxia as the initial step causing neoangiogenesis and a low degree of endothelial proliferation in DAVFs. Such hypoxia might be caused by venous hypertension or venous thrombosis as it was previously suggested by other authors.