三叉神经鞘瘤的诊断与手术入路选择

目的 探讨三叉神经鞘瘤的诊断与手术入路选择。方法 回顾性分析28例三叉神经鞘瘤的临床资料。结果 肿瘤获全切除25例，次全切除2例和大部切除1例。出院时好转27例，加重1例。结论 三叉神经鞘瘤可分成为：（1）颅中窝型；（2）颅后窝型；（3）颅中后窝型；（4）颅外型；（5）颅中窝颅内外沟通型；（6）颅中后窝颅内外沟通型。颅中窝型肿瘤宜取翼点或改良翼点入路；颅后窝型肿瘤宜取枕下乙状窦后入路；颅中后窝型肿瘤宜取颞底经天幕入路。颅中窝颅内外沟通瘤宜取颞下硬脑膜外入路。     

椎-基底动脉冗长扩张综合征分级与颅后窝容积的相关性

目的 探讨椎-基底动脉冗长扩张综合征（VBD）分级与颅后窝容积的相关性。方法 2021年6月至2022年6月前瞻性收集VBD共18例及正常成人18例（对照）,根据头颈CTA进行VBD分级,头颅正中矢状位CT影像测量颅后窝标志间距离,3D Slice软件重建颅后窝并计算颅后窝容积。结果 基底动脉分叉高低水平分级1级3例,2级12例,3级3例;基底动脉偏移度程度分级1级3例,2级6例,3级9例。VBD病人颅后窝高径、颅后窝矢状径、枕上长度、颅后窝体积较对照组均明显缩小（P<0.05）。随VBD分级增高,颅后窝体积存在增加趋势。结论 VBD病人颅后窝容积明显减小,VBD分级与颅后窝容积存在相关性。     

Epidural hematomas of the posterior fossa in children

The authors report 3 cases of epidural hematoma of the posterior fossa in children. The clinical signs and symptoms are discussed. Onset of symptoms is not necessarily acute. The radiological findings are discussed. Epidural hematomas of the posterior fossa in children have a tendency to liquefy earlier than supratentorial hematomas. We emphasize the value of computed tomography for the diagnosis of epidural hematoma of the posterior fossa. One should keep in mind the possibility of the presence of an epidural hematoma of the posterior fossa in the treatment of head injury in children, even in the case of a minor head injury.     

Aseptic meningitis after posterior fossa surgery treated by pseudomeningocele closure

Aseptic meningitis is a recognised complication after posterior fossa surgery. It is often self limiting but occasionally runs a protracted course requiring repeated CSF examination to exclude infection, and treatment with systemic steroids. A patient is described with aseptic meningitis after posterior fossa surgery who underwent posterior fossa re-exploration nearly 3 years after the initial operation. This disclosed a pseudomeningocele, which was closed. The patient remains symptom free almost 2 years after closure. In this case of chronic aseptic meningitis after posterior fossa surgery, closure of the pseudomeningocele found at exploratory surgery led to resolution of the symptoms.     

Comparisons of the clinical and radiological features and surgical management of posterior fossa meningiomas and acoustic neuromas

Next to acoustic neuromas, meningiomas are the most common benign tumour of the posterior fossa. This paper reviews the personal experience of one of the authors with the management of 26 posterior fossa meningiomas and 212 acoustic neuromas. The aim was to compare the clinical and radiological features of these two types of posterior fossa tumours to determine whether they can be differentiated preoperatively. The study also aimed at analysing the surgical treatment of posterior fossa meningiomas. The results showed that posterior fossa meningiomas can usually be differentiated from acoustic neuromas on the basis of clinical and radiological features. Preoperative differentiation aids surgical management, especially for selection of surgical approach. In most instances, posterior fossa meningiomas can be totally resected with minimal morbidity and mortality.     

后颅窝手术后颅内感染的防治分析

目的探讨后颅窝手术后颅内感染的易感因素及防治措施。方法回顾性分析对我科2005年6月至2013年6月后颅窝手术后继发生颅内感染的28例患者的临床资料。皮肤切开前应用抗生素,手术时间〉4 h者加用1次,术毕用生理盐水250ml＋注射液万古霉素500 mg反复冲洗;全部患者采用全身用抗生素＋脑脊液引流＋鞘内应用抗生素治疗。结果 28例患者颅内感染时间发生在开颅术后3～14 d。27例颅内感染在6周内得到有效控制,1例自动出院。结论后颅窝手术术后容易并发颅内感染,采用全身用抗生素＋脑脊液引流＋鞘内应用抗生素是一种治疗后颅窝手术术后并发颅内感染的有效方法。     

Posterior fossa syndrome after surgical removal of a pineal gland tumor

Posterior fossa syndrome, characterized by oromotor or oculomotor apraxia, emotional lability, and mutism, occurs in some children after infratentorial tumor resection, and is thought to involve injury to the dentatothalamocortical tract. Previous cases of posterior fossa syndrome involved pediatric patients with cerebellar and other posterior fossa tumors. To heighten awareness that posterior fossa syndrome can occur after resections of tumors in other neuroanatomic locations, we present a 16-year-old boy who developed this syndrome after surgical removal of a supratentorial pinealoma, and we include a discussion of his self-reported signs.     

Posterior fossa tension pneumocephalus

Frontal tension pneumocephalus is seen as a complication of surgery in the sitting position. A case of posterior fossa tension pneumocephalus occurring after operation for a posterior fossa abscess is presented.     

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.     

Posterior Fossa Teratomas in Adults : A Systematic Review

ObjectiveThe occurrence of posterior fossa teratomas in adulthood is extremely rare. In this study, we aimed to report our experience with two cases of posterior fossa mature teratoma in adults who underwent surgical resection. We also performed a systematic review of published papers available to date. MethodsWe retrospectively reviewed the electronic medical records of patients who had onset of posterior fossa teratomas in adulthood at our institute between 1995 and 2020. We evaluated the clinical, radiographic, and pathological features of mature teratomas at the posterior fossa in adulthood. Furthermore, we searched the PubMed, EMBASE, and Web of Science database and reviewed published articles. ResultsWe found 507 articles on database review; of them, 102 were duplicates and 389 were excluded based on the inclusion criteria. Finally, 16 cases of posterior fossa from the web search and related articles. Subsequently, we added two cases that underwent surgery at our institute. We analyzed a total of 18 cases of mature teratomas. Headache was the most common (55.6%) symptom. The teratomas showed heterogeneous signals on magnetic resonance imaging. Thirteen patients (72.2%) had lesion at midline, five patients (27.8%) had calcification. Surgical resection was performed in all patients. No studies reported recurrence after resection. ConclusionThe occurrence of posterior fossa teratomas in adulthood is difficult to diagnose at the initial stage. Radiographic diagnosis alone can lead to misdiagnosis. Pathological confirmation is essential. Surgical resection is a curative option for posterior fossa teratomas in adulthood.     

Herniation of cerebellar tonsils following supratentorial shunt placement

Acquired Chiari 1 following ventriculoperitoneal shunting is an extremely unusual event. We report the case of an 8-year-old boy who presented with clinical and radiological signs of cerebellar tonsil herniation shortly after the placement of a cystoperitoneal shunt. Quantitative analysis of posterior fossa volumes (PFV) revealed that the patient had a smaller posterior fossa than age-matched normal controls. This abnormality, expressed as a decreased ratio between the posterior fossa and the supratentorial cavities (PFR), had already been present when the preoperative MRI was done. Our results suggest that pre-existing structural abnormalities in the posterior fossa may constitute an important factor in the development tonsillar herniation following supratentorial shunts. Received: 6 November 1997     

Endoscopic third ventriculostomy in the treatment of hydrocephalus in posterior fossa tumors in children

OBJECT: The purpose of the present study is to assess the effectiveness of endoscopic third ventriculostomy (ETV) in children with hydrocephalus related to posterior fossa tumors. METHODS: Between September 1999 and December 2002, 63 children with posterior fossa tumors were treated at Santobono Hospital in Naples, Italy. Twenty-six patients had severe hydrocephalus. In order to relieve intracranial hypertension before tumor removal, 20 were treated with ETV, and 6 with ventriculo-peritoneal (VP) shunts. Twenty patients with mild hydrocephalus were treated with diuretics, corticosteroid agents, and early posterior fossa surgery, and 17 patients who did not have hydrocephalus were treated by elective posterior fossa surgery. Another 4 ETV were performed in the management of postoperative hydrocephalus. RESULTS: Preoperative ETV procedures were technically successful. One was complicated by intraventricular bleeding. The successful 19 preoperative ETV resolved intracranial hypertension before posterior fossa surgery in all cases. Three of these 19 patients developed postoperative hydrocephalus and were treated by VP shunt insertion after posterior fossa surgery. Out of the 4 ETV performed after posterior fossa surgery, only 2 were successful, both when the shunt malfunctioned. CONCLUSIONS: Endoscopic third ventriculostomy should be considered as an alternative procedure to ventriculo-peritoneal shunting and external ventricular draining for the emergency control of severe hydrocephalus caused by posterior fossa tumors, since it can quickly eliminate symptoms, and hence, can delay surgery scheduling if required. Even though ETV does not prevent postoperative hydrocephalus in all cases, it does protect against acute postoperative hydrocephalus due to cerebellar swelling. In addition, it eliminates the risks of cerebrospinal fluid (CSF) infection related to external drainage and minimizes the risk of overdrainage because it provides more physiological CSF drainage than the other procedures. Since postoperative hydrocephalus is very often physically obstructive, ETV should always be considered a possible treatment procedure.     

Chiari Ⅰ型畸形微创后颅窝减压术

目的 探讨微创后颅窝减压术对Chiari Ⅰ型畸形的治疗效果及手术并发症发生率.方法将自2006年1月至2009年1月接受微创后颅窝减压术的32例患者设为治疗组,自2001年1月至2005年12月接受传统后颅窝减压术的35例患者设为对照组,比较2组患者的治疗结果、手术并发症发生率等.结果 2组患者的治疗结果、术后脊髓空洞的变化差异均无统计学意义(P>0.05).2组手术并发症发生率分别为6.3%和31.4%,治疗组明显低于对照组,差异有统计学意义(x~2=6.777,P=0.009).结论 微创后颅窝减压术对Chiari Ⅰ型畸形的治疗效果与传统后颅窝减压术相当.而手术并发症相对较少.     

Posterior fossa decompression and the cerebellum in Chiari type II malformation: a preliminary MRI study

Objectives  

Chiari type II malformation (CII) is a congenital deformity of the hindbrain. The posterior fossa and cerebellum are small in CII. The cerebellar atrophy is associated with cognitive and motor deficits. Brainstem compression occurs in some patients with CII for whom posterior fossa decompression may be life saving. The aim was to determine whether posterior fossa decompression can prevent or reduce the cerebellar atrophy in CII.     

颅后窝重建术治疗Chiari I畸形合并脊髓空洞症

目的探讨后颅窝重建术(后颅窝减压+硬脑膜成形+小脑扁桃体切除+蛛网膜粘连分解)治疗Chiari I畸形合并脊髓空洞症的方法及疗效。方法 2002年11月至2008年1月对收治的46例Chiari I畸形合并脊髓空洞症患者行后颅窝重建术。结果后颅窝重建术症状改善率84.8%,脊髓空洞长度明显减小,KPS评分显著改善。结论后颅窝重建术是治疗Chiari I畸形合并脊髓空洞症较为合理的术式。     

Basichondrocranium anomalies in adult Chiari type I malformation: a morphometric study

The purpose of this study was to determine the frequency of anomalies of the basichondrocranium in a series of 42 patients with Chiari type I malformation compared with a control group of 46 subjects. Sixteen patients also had syringomyelia. Linear, angular and posterior fossa surface area measurements were taken on conventional lateral skull x-rays. Posterior fossa volume was estimated by CT scanning. In patients there was shortening of clivus length, Twining-opisthion distance and Chamberlain's line. Basal and Boogard angles were enlarged. The size of the posterior fossa was smaller in patients than in controls. Only 10 (23.8%) patients had no evidence of occipital dysplasia. When discriminant analysis was applied to the data, the most discriminative variables were posterior fossa area and clivus length which allowed accurate identification of 76% of patients as belonging to the patient group and 79% of controls as belonging to the control group. These findings prove that under-development of the basichondrocranium with a small size of the posterior fossa is an outstanding feature in adult Chiari type I malformation, and support the hypothesis that tonsillar ectopia is secondary to the disproportion between the posterior fossa and the cerebellum, which is forced to grow into the cervical spinal canal.     

Chronic subdural hematoma of the posterior fossa associated with cerebellar hemorrhage: report of rare disease with MRI findings

Chronic subdural hematoma of the posterior fossa is an uncommon entity, and spontaneous lesions are very rarely described, occurring mostly during anticoagulation therapy. The association of the posterior fossa chronic subdural hematoma with spontaneous parenchymal hemorrhage without anticoagulation therapy was never related in the literature, to our knowledge. We describe a case of a 64 year-old woman who suffered a spontaneous cerebellar hemorrhage, treated conservatively, and presented 1 month later with a chronic subdural posterior fossa hematoma.     

Case series: acute mood symptoms associated with posterior fossa lesions in children

Nineteen children were acutely dysphoric, inattentive, irritable, and sometimes mute following midline posterior fossa neoplasm resection and arteriovenous malformation hemorrhage. These symptoms represent an acute manifestation of the cerebellar cognitive affective syndrome. The authors aimed to describe the acute psychiatric changes in mood and behavior in children with posterior fossa lesions and to evaluate the relationship of posterior fossa syndrome to cerebellar cognitive affective syndrome.     

Transcranial cerebellar herniation following craniotomy: Case report and literature review

To report a case of post-surgical encephalocele through craniotomy burr holes following the resection of a meningioma of the posterior fossa. A 49-year-old female presented in the emergency room with cephalea. The MRI showed a meningioma of the convexity of the posterior fossa. A resection was performed and the bone flap replaced. The patient recovered uneventfully and was discharged. After 30 days the patient consulted referring cephalea, vomiting and imbalance. Brain MRI revealed a trans-cranial cerebellar herniation through the craniotomy burr holes. An urgent surgery was performed to repair the encephalocele. Post-surgical brain MRI was performed and did not show complications.Post-surgical encephalocele is an uncommon complication after the resection of a posterior fossa lesion. To avoid this complication, it is recommended thorough dural and bony closure, particularly in the posterior fossa surgeries and in high-risk patients.     

Similarity of brain CT appearance in spongy degeneration to that of subacute necrotizing encephalomyelopathy

Reports of brain computed tomography (CT) findings in spongy degeneration describe radiolucent changes of the cerebral white matter, but have not described changes in the posterior fossa. We describe an infant with spongy degeneration in whom CT scans detected brainstem, cerebellar, and cerebral white matter radiolucencies before the diagnosis was established. The posterior fossa CT findings resembled the periventricular changes described in subacute necrotizing encephalomyelopathy (SNE). As the patient's initial clinical findings were consistent with SNE, the similarity of the posterior fossa radiolucencies was misleading. Without basal ganglia or thalamic involvement, or without variability in their appearance over time, posterior fossa periventricular radiolucencies are not diagnostic of a specific degenerative disorder.