Cholesterol granuloma in the middle cranial fossa: report of two cases

We report two cases of cholesterol granuloma in the middle cranial fossa. On CT the lesions appeared as a nonspecific, nonenhancing soft-tissue mass with bone erosion. On MRI they were seen as areas of high signal intensity surrounded by a low-intensity peripheral zone on both T1- and T2-weighted images. Cholesterol granuloma is thought to occur when pneumatised cellsin the temporal bone become obstructed. Although this lesion usually occurs in the petrous bone, it can extend to the middle cranial fossa. The diagnosis and surgical management are discussed.     

Cervical spinal deformity following craniotomy and upper cervical laminectomy for posterior fossa tumors in children

Spinal deformity is not usually regarded as a potential complication of posterior fossa tumor resection. After cervical subluxation had been recognized in 2 children following removal of posterior fossa tumors, a review was carried out to determine the incidence of this complication. Of the 72 children who had undergone resection of a posterior fossa tumor, 4 patients, including the original 2, developed a cervical spinal deformity. Factors that predisposed to this complication included laminectomy of C2 or lower, local wound complications and possibly post-operative neck weakness. It is important to be aware that cervical subluxation can occur after resection of posterior fossa tumors, when laminectomy extending below C1 has been performed. Patients at risk should be followed closely.     

Detectability of cerebral hemisphere ischaemic infarcts by CT within 6 h of stroke

To determine how early and how reliably ischaemic brain infarcts can be detected on CT within 6 h of the onset of cerebral hemisphere strokes, 44 such studies were interpreted by an experienced neuroradiologist blinded to clinical signs, but aware that the cohort was a stroke population. He was asked to detect and localise an area of parenchymal low density and/or focal brain swelling. A follow-up study showing the definite infarct served as a reference in each case. In 38 patients areas of slightly low density were seen, and in 36 follow-up CT confirmed infarcts in the locations indicated. In 2 patients the reading was false positive. In 6 patients no low density focus could be detected. In these 8 patients examined by CT within 180 min of the stroke, no low density could be identified, even in retrospect with the knowledge of the findings on follow-up. Thus, 42 readings (95%) were true positive or true negative; 2 were false positive; and none was a false negative. CT within 6 h of the onset of symptoms has a mean sensitivity of 82% (36/44) for ischaemic cerebral hemisphere infarcts. By contrast, its sensitivity to ischaemic parenchymal low density is low during the initial 2 h. The early development of hemispheric infarcts can be detected reliably if the radiologist is familiar with the signs.     

Vascular permeability to sodium fluorescein in the rabbit cranial nerve root: possible correlation with normal cranial nerve enhancement on gadolinium-enhanced magnetic resonance imaging

Vascular permeability in cranial nerve roots was examined after intravenous injection of sodium fluorescein in the adult rabbit. Fluorescence was observed in the distal nerves through the following portions: intracavernous portion of the oculomotor nerve, distal internal auditory camal segment of the facial nerve, and ganglionic portions of the trigeminal, glossopharyngeal and vagus nerves. In the acoustic nerve, the vestibular ganglion showed fluorescence. No fluorescence was observed in the olfactory or optic nerves. During in vivo gadolinium-enhanced magnetic resonance imaging (Gd-MRI) of two separate animals, trigeminal nerve enhancement was observed in the region showing fluorescence. Histologically, intense fluorescence was observed in ganglia and external nerve sheaths of the cranial nerves showing macroscopic fluorescence. A slight fluorescence was also seen in endoneurial connective tissue but not observed within the nerve fibers. The results of this study suggest that the physiological enhancement of human cranial nerves seen on Gd-MRI may correlate with vascular permeability.     

The anatomical basis for ultrasonography of the lateral pterygoid muscle and the infratemporal fossa

Summary The infratemporal fossa and its contents (particularly the pterygoid muscles) is a region difficult to explore, in spite of its importance in odontostomatological pathology. In order to reduce the indications that justify examination by computed tomography and magnetic resonance imaging, for reasons of economy of health, the authors describe by application of orientated anatomical slices the way in which ultrasonography can be performed. Only the posterior approach between the mandible laterally and the mastoid process medially provided consistently adequate exploration of the infratemporal fossa and the pterygoid muscles.Communication presented at the French Section of the European Association of Clinical Anatomy meeting, Bobigny, France, June 20, 1992     

经下颌入路切除颅中凹底与颞下窝沟通肿瘤

目的研究经下颌入路切除颅中凹底与颞下窝沟通肿瘤和术后重建的方法。方法采用经下颌入路及与额颞联合入路对11例此区域肿瘤行显微手术切除，手术重建包括硬膜修补、手术残腔消除及骨固定。结果肿瘤全切除11例，次全切除1例，部分切除1例。无死亡及严重残疾。12例临床症状显著改善。2例出现并发症。结论经下颌入路及与额颞联合入路能提供良好的显露．可安全、彻底地切除肿瘤，提高病人生活质量：严格掌握手术指征，使用显微技术，可靠重建颅底，及重视病人术后的功能和美观等，是手术成功的关键。     

经乙状窦后进路切除跨颅中后窝巨大胆脂瘤

目的：介绍手术切除跨颅中后窝生长巨大胆脂瘤的体会和注意事项。方法：采用乙状窦后进路显微外科方法治疗７例跨颅中后窝巨大胆脂瘤。结果：随访５个月～３年，７例术侧症状均消失，未见肿瘤复发征象。结论：表明乙状窦后进路可一期全部切除跨颅中后窝巨大胆脂瘤。     

Value of precraniotomy shunts in children with posterior fossa tumours

Seventy children with posterior fossa tumours treated over a period of 6 1/2 years were studied. Most patients presented in the late stage of disease. Sixty-four required insertion of a precraniotomy shunt for one or more of the following: persistent vomiting, severe headache, dehydration, poor general condition, failing vision, altered sensorium, marked periventricular lucency, and brain stem involvement deferring total removal of the tumour. Insertion of precraniotomy shunt improved the general condition and signs and symptoms of increased intracranial pressure. It also provided a lax brain during definitive surgery and a smooth postoperative course. Shunt-related complications, consisting of block and/or infection, were observed in 21 patients. It was concluded that precraniotomy shunt is important in the management of children with posterior fossa tumours in developing countries where these patients present in the late stage of disease.     

人胎儿菱形窝的扫描电镜观察

目的 探索脑—脑脊液免疫神经内分泌回路的形态结构。方法 用扫描电镜的方法观察了人胎儿菱形窝室管膜的超微结构。结果 菱形窝室管膜上布满了大量的纤毛和微绒毛，纤毛的分布有一定的部位差异。结论 菱形窝室管膜上存在着神经元样胞体、神经胶质样细胞和类组织细胞，纤毛或微绒毛丛中有神经纤维和树突末端。室管膜上神经纤维从神经细胞或自室腔外穿人。     

异体颅骨、骨形态发生蛋白及骨膜修复颅骨巨大缺损

以异体颅骨和骨形态发生蛋白为材料,应用部分带蒂骨膜瓣和头皮瓣成功修复4例巨大颅骨缺损。缺损范围最小为9cm×7cm,最大13cm×11.5cm。经术后1～2年随访,外观均好,且移植异体骨逐渐被吸收,新生骨已形成。