Clinical evaluation of an isolated fourth ventricle

Since the introduction of the CT scan in 1976, we have experienced 6 cases of the isolated fourth ventricle among 244 hydrocephalic patients (2.5%). Age at diagnosis of the isolated fourth ventricle ranged from 1 year 8 months to 13 years (mean age, 8 years, 6 months). The time interval between the first shunting procedure and the diagnosis of the isolated fourth ventricle varied from 1 year 5 months to 7 years 4 months (mean interval, 4 years 1 months). The prior hydrocephalus were due to intraventricular hemorrhage in two patients, meningomyelocele in a patient and brain tumor in three patients. Two patients had history of cerebrospinal fluid (CSF) infection and five cases underwent multiple shunt revisions. Posterior fossa signs were evident in all cases. It was quite easy to make a diagnosis of the isolated fourth ventricle with CT scan, which demonstrated a large rounded or pear-shaped midline cyst in the posterior fossa. Slit-like lateral ventricles were noted in three cases, while the remaining three had enlarged lateral ventricles. Ventriculography confirmed the isolation of the fourth ventricle in 5 cases. Metrizamide which had been injected into the fourth ventricle was diluted when CT scan was performed 48 hours later, and contrast medium disappeared since then. Magnetic resonance imaging (MRI) well showed the characteristic findings of the isolated fourth ventricle: cystic dilatation of the fourth ventricle, compression and distortion of the brain stem, upward tentorial herniation, occlusion of the aqueduct, downward displacement of the occipital lobe, septum formation of the fourth ventricle and accompanied anomalies such as, Chiari malformation or syringomyelia.(ABSTRACT TRUNCATED AT 250 WORDS)     

Etiological differences between the isolated lateral ventricle and the isolated fourth ventricle

Objective To determine if an etiological difference exists between isolation of the lateral ventricle and isolation of the fourth ventricle after ventricular shunting.Methods Cases of symptomatic isolation of the lateral and fourth ventricles were reviewed retrospectively. The ages at presentation of ventricular isolation, the time course to development of isolation, the number of shunt surgeries leading up to symptomatic isolation, the types of shunt valves utilized, and the background of infection were analyzed.Results Twenty-six patients had lateral ventricle isolation and 11 patients had fourth ventricle isolation. Infection, hemorrhage, Chiari malformation/myelomeningocele, and aqueductal stenosis were factors contributing to hydrocephalus requiring treatment in these patients. Compared to 26.9% of patients with lateral ventricle isolation, 90.9% of patients with fourth ventricle isolation had a previous history of infection.Conclusions Prior meningitis and ventriculitis frequently contributed to fourth ventricle isolation. Lateral ventricle isolation seems to arise from functional obstruction of the foramen of Monro related to prior shunting.     

Endoscopic transaqueductal or interventricular stent placement for the treatment of isolated fourth ventricle and pre-isolated fourth ventricle

Object

The aim of our study is to evaluate the effectiveness of endoscopic transaqueductal or interventricular stent placement into the fourth ventricle for isolated fourth ventricle (IFV) and pre-isolated fourth ventricle (PIFV), in which occlusion of the fourth ventricle outlets and dilation of the fourth ventricle are seen while the aqueduct is still patent.

Methods

We retrospectively analyzed pediatric patients who underwent endoscopic stent placement for IFV or PIFV.

Results

Five patients with IFV and four patients with PIFV underwent endoscopic stent placement. The mean age was 11.5 months. Three patients with IFV underwent aqueductoplasty with stent connected to an extracranial shunt system. Two patients with IFV and supratentorially protruded fourth ventricle underwent interventriculostomy with stent. In these patients, the stent was not connected to the shunt system as functional shunt had been already placed using the contralateral ventricle. In four patients with PIFV, transaqueductal stent was placed and connected to the extracranial shunt system. In all patients, preoperative symptoms improved and magnetic resonance imaging demonstrated reduction of the size of the fourth ventricle. The mean follow-up period was 49.6 months (range 5 to 99 months). Three patients (33 %) underwent reoperation due to obstruction of the abdominal catheter, partial occlusion of the ventricular catheter, and retraction of the fourth ventricular catheter.

Conclusion

The endoscopic transaqueductal or interventricular stent placement into the fourth ventricle for the treatment of IFV is considered to be effective and safe. The transaqueductal stent placement for PIFV is also considered to be effective for resolution of symptoms and prevent progression into IFV.     

Disproportionately large communicating fourth ventricle resulting from adjustable valve shunt in an infant

Disproportionately large communicating fourth ventricle (DLCFV) is usually experienced in adults with no previous experience of shunting. We present a case of an infant with an enlarged fourth ventricle similar to isolated fourth ventricle (IFV) which appeared after shunting. The patient's brain stem symptoms and the abnormal appearance of the fourth ventricle were dramatically ameliorated simply by reducing the opening pressure of the adjustable valve of the ventriculo-peritoneal shunt. The present case suggests that in the present era, with adjustable or programmable valve shunt a common procedure, DLCFV may occur, at least temporarily, even in infants and even after shunting.     

Cranio-cervical decompression and expansile duroplasty for isolated fourth ventricle in a patient with Chiari II malformation

The management of isolated fourth ventricle in Chiari II malformation remains a complex challenge. Commonly accepted treatment options have been associated with high rates of complications and failure. Cranio-cervical decompression and autologous expansile duroplasty may be an effective primary intervention for this condition.     

第四脑室肿瘤显微手术治疗

我院自1995年1月至2005年4月显微手术治疗第四脑室肿瘤12例，取得了较好的效果。现将有关临床资料总结如下.     

Lateral recess cysts in two cases of isolated fourth ventricle

We report two cases of isolated fourth ventricle with lateral recess cysts. The background, clinical features, treatment and outcomes are presented and discussed. We speculate on the association of these two conditions and propose possible explanations for the clinical features.     

儿童第四脑室肿瘤显微外科治疗策略

目的探讨儿童第四脑室肿瘤的生物学特点及显微外科治疗策略。方法 1998年至2009年收治的儿童第四脑室肿瘤患者45例,对其病理特点、临床表现、影像学变化、手术操作和预后等方面进行回顾性分析。结果肿瘤全切除36例,次全切除及大部切除9例;术后病理示髓母细胞瘤28例,室管膜瘤14例,星形细胞瘤3例;术后临床症状好转32例,无改善10例,恶化2例,1例患者死于严重脑干水肿;术后复查有4例因脑积水行脑室-腹腔分流术。结论儿童第四脑室肿瘤首发症状多种多样,MRI对于诊断与手术有重要的意义,采取合适的显微神经外科策略是提高手术疗效的关键。     

Neonatal hemifacial spasm and fourth ventricle mass

Congential hemifacial spasm is a rare condition that is characterized by the occurrence of paroxysmal hemifacial contractions in neonates. We review the clinical, neurophysiological, neuroimaging, and histopathological findings, as well as the differential diagnosis, therapeutic approach, and outcome of all the described cases. Moreover, we report two new cases including the ictal video-electroencephalography recordings. Hemifacial spasm starts early in life, and is characterized by unilateral, involuntary, irregular tonic or clonic contractions of muscles innervated by the seventh cranial nerve. Hemifacial spasm is associated with eyelid blinking, and sometimes with breathing irregularities, hyperventilation, and/or other neurological manifestations (dystonic movements, nystagmus). Interictal and ictal video-electroencephalography did not reveal epileptiform abnormalities. In all cases, brain magnetic resonance imaging showed a mass involving the cerebellar peduncle, the cerebellar hemisphere, or the floor of the fourth ventricle. The semiology of the paroxysmal attacks is probably due to the activation of cranial nerve nuclei through intralesional hypersynchronous discharges, as shown by the intraoperative recordings and functional brain imaging described in the literature. We point out the importance of identifying such seizures in order to make an early diagnosis of the underlying cerebral lesion.     

Anorexia: an early sign of fourth ventricle astrocytoma in children

Introduction

Paediatric low-grade astrocytomas of the fourth ventricle are rare tumours, generally revealed by hydrocephalus. However, some patients present with a history of severe anorexia. It might be a harbinger, which if recognized, could lead to earlier diagnosis. We decided to examine our database in order to evaluate the incidence and signification of anorexia in this context.

Methods

Retrospective monocentric study of cases of low-grade astrocytomas of the fourth ventricle operated between 1991 and 2012 in our paediatric neurosurgery department. We particularly observed the clinical presentation and long-term clinical, oncological and radiological evolution. Non-parametrical tests were used (Mann–Whitney, Fisher).

Results

We reviewed 34 cases, 31 pilocytic astrocytomas and 3 diffuse astrocytomas, 16 boys and 18 girls, (M/F ratio 0.89). Mean age at diagnosis was 8 years old. Seven presented with notable anorexia, the average BMI in this group was ≤2 standard deviation (SD); with clinical signs evolving for 11.5 months. Twenty-seven children had no anorexia; average BMI in this group was +1 SD, with clinical evolution for 6 months on an average of p?Conclusion Anorexia with stunted body weight curve is a non-exceptional presentation in children with low-grade astrocytomas of the fourth ventricle. Unexplained or atypical anorexia with negative etiologic assessment should prompt cerebral imaging. Clinical improvement after surgical resection, could suggest a possible interaction between tumour tissue and appetite-suppressing peptide secretion.     

Management strategies for treatment of the trapped fourth ventricle

BACKGROUND: An isolated or trapped fourth ventricle (TFV) is an occasional, serious sequela of hemorrhagic, infectious, or inflammatory conditions of the central nervous system. The TFV usually occurs after successful shunting of the lateral ventricles. It may be heralded by delayed clinical deterioration after an initial period of symptomatic improvement. The typical clinical findings suggest an expanding posterior fossa mass lesion. Surgical treatments include CSF diversionary procedures as well as open and endoscopic approaches. Complications related to the treatment of the TFV are common and relate to catheter obstruction and cranial nerve or brainstem dysfunction. METHODS: The author reviews the clinical features, pathophysiology, and available treatment options for the TFV, with special reference to complication avoidance and advances in ventriculoscopy and frameless stereotaxy. CONCLUSIONS: Treatment of the TFV remains a formidable challenge. However, prompt recognition and intervention may aid in the preservation of life and neurological function.     

CT stereotaxy guided lateral trans-cerebellar programmable fourth ventriculo-peritoneal shunting for symptomatic trapped fourth ventricle

A trapped fourth ventricle is a rare clinico-radiological entity producing symptoms suggestive of a progressive posterior fossa mass lesion. It is mainly reported in children as a late complication of lateral ventricular shunting to relieve infantile post-meningitic or post-hemorrhagic hydrocephalus. Optional treatment of the trapped fourth ventricle remains controversial. Placement of fourth ventricular shunting via a conventional midline approach can be fraught with complications in about 40% of the patients. Authors report a successful CT Stereotaxy guided high pressure (80 mm H(2)O) programmable fourth ventriculo-peritoneal shunting via a lateral trans-cerebellar approach in a 14-year-old girl with a trapped fourth ventricle, which occurred as a late complication of ventriculo-peritoneal shunting in her infancy. Her preoperative symptoms of raised intracranial pressure, bobble-head doll syndrome and bilateral abducens palsies completely improved following the surgery. Lateral trans-cerebellar stereotactic placement of the fourth ventricular catheter and the use of high-pressure (low flow) programmable shunt (to avoid complications associated with over drainage) are beneficial in some patients with trapped fourth ventricle.     

A rare case of trapped fourth ventricle: an unique symptom appeared after fourth ventriculo-peritoneal shunting]

We experienced a unique case of trapped fourth ventricle after shunting for post-meningitic hydrocephalus. A five-year-old infant was diagnosed as meningitis shortly after his birth, and secondarily suffered from hydrocephalus. He underwent lateral-ventriculo-peritoneal shunting, fourth-ventriculo-cisterna-magna shunting and so on, but bilateral abducens palsy appeared. The following head CT and MRI revealed "trapped fourth ventricle". Though there are several case reports of trapped fourth ventricle with abducens palsy, most of them followed enlargement of the fourth ventricle; nevertheless in our case, abducens palsy appeared when the fourth ventricle reduced in size and the symptom vanished when it enlarged. We thought that a traction force to the abducens nerve had occurred also in the condition of reduced fourth ventricle size, because there would have been a dense adhesion after meningitis in his subarachnoidal space. We tried to improve his symptom in one way or another by keeping the fourth ventricle in appropriate volume. His abducens palsy was controlled by switching the on-off valve between forth ventricle and peritoneum. We expect that a higher-pressure programmable shunt valve or a lower-flow-regulating shunt system be invented in order to cope with the cases like ours.     

Partially sequestered fourth ventricle: CT and MR diagnosis of an unusual entity

Encystment of the fourth ventricle, due to occlusion of the aqueduct as well as the foramina of Magendie and Luschka has been described previously. Partial sequestration such as that encountered in two cases described is a less common entity. In these two cases, the aqueduct of Sylvius was occluded, but the basal foramina (Magendie and Luschka) were patent. We discuss this partial sequestration or communicating hydrocephalus of the fourth ventricle on the basis of MR and CT scan findings. Although computed tomography following water soluble cisternography did diagnose the entity indirectly MRI proved to be a superior tool. It permitted direct visualization of the basal foramina noninvasively.