Ventricle Roof Research Articles

Fourth ventricular roof angle does not predict surgical outcome in paediatric patients with Chiari I malformation.

Pre-operative fourth ventricle roof angle (FVRA) has recently been highlighted as a novel radiographic predictor of clinical severity in Chiari type-I malformation (CM-I) as reported by Seaman et al. (J Neurosurg Pediatr 25:1-8, 2021). This has led to suggestions that FVRA could be included in algorithms to determine indications for surgery. We aimed to test the accuracy of FVRA as a predictor of clinical severity and its effect on post-operative outcome in a large retrospective cohort of paediatric patients who underwent decompression for CM-I. Patients undergoing craniocervical decompression for CM-I at the Queensland Children's Hospital and Mater Hospital, Brisbane, between 2006 and 2018 were included. Data was collected from 66 patients aged 0-18years. Post-operative outcome was assessed by calculating Chicago Chiari Outcomes Score (CCOS) at follow-up. The FVRA was taken from a mid-sagittal T1-weighted MRI as previously described (Seaman et al. in J Neurosurg Pediatr 25:1-8, 2021). The angle is subtended between superior and inferior medullary velum. Whilst results from Seaman et al. demonstrated a strong correlation between a FVRA > 65° and symptomatic CM-I, this did not translate to our dataset (p = 0.61). Additionally, pre-operative FVRA is not useful as a predictive tool for post-surgical outcome as assessed by CCOS (p = 0.50), and post-operative reduction in FVRA did not correlate with improved outcomes (p = 0.81). We did note significantly worse outcomes in patients presenting with pre-operative brainstem dysfunction (p = 0.03). Paediatric CM-I is a challenging cohort to manage, often due to young age and a lack of language skills. There is a heavy reliance on radiological findings. Whilst FVRA has previously been reported to be of value as a determinant of clinical severity in adult and paediatric patients, we find that this measurement is of dubious value in our retrospective cohort.

Hemorrhagic Fourth Ventricle Colloid Cyst: A Report of an Unusual Presentation at an Uncommon Location

AbstractColloid cysts are benign cystic lesions characteristically arising from the third ventricle roof close to the foramen of Monro. Although incredibly rare, hemorrhage within a third ventricular colloid cyst is sparsely reported. To the best of our knowledge, no cases of hemorrhage within the fourth ventricle colloid have ever been documented. Here, we present an interesting case describing a hemorrhagic colloid cyst situated within the fourth ventricle of a 55-year-old female patient who presented with symptoms of headache, vomiting, and gait imbalance. The cyst was excised during surgery via a suboccipital microscopic telovelar approach. Our findings led us to the conclusion that, despite being extremely rare, colloid cysts in the fourth ventricle can present with hemorrhagic episodes, which can exacerbate symptoms and hasten neurological decline. As a result, the presence of unusual radiological characteristics in a fourth ventricle lesion should prompt medical practitioners to suspect an atypical colloid cyst. This consideration can be pivotal in making informed surgical decisions. Expedited management and a microsurgical approach are recommended strategies for a better outcome.

Use and meaning of the anatomical terms plexus choroideus and tela choroidea in veterinary and human medicine.

The anatomical terms plexus chor(i)oideus (CP) and tela chor(i)oidea (TC) are listed without explanations in the official nomenclature handbooks Terminologia Neuroanatomica and Nomina Anatomica Veterinaria. Definitions of CP and TC exhibit discrepancies in medical dictionaries and anatomy handbooks. The aim of our study was to analyse this problem in detail and to discuss a possible unified use of the terms in science and teaching. We conducted a systematic literature review based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, identifying and analysing relevant scholarly articles. Additionally, comprehensive original handbooks on human and veterinary anatomy in English and other European languages were examined. The definitions of the terms CP and TC differed considerably between articles and did not match the most frequently given explanations in handbooks. In general use, it seems to have become accepted that TC represents the smooth, thin part of the roof of third and fourth ventricles, and CP the frond- or fringe-like vascularised structures invaginated into lateral, third and fourth ventricles. However, it is controversial which tissue layers should be included in their description. Etymologically, only the vascular network should be termed (choroid) plexus, but embryologically and functionally, epithelium, pial connective tissue and vascular network form an inseparable entity. Similarly, the smooth part of the ventricle roof consists of a (less) vascularised pia-derived stroma and lining epithelium. Including all these layers in CP as well as TC definition might be advisable and also corresponds to the use of the terms in clinical context.

Endoscopic-assisted paramedian supracerebellar infratentorial approach to the posterior portion of the third ventricle: anatomical study and surgical cases.

To date, morphometrical data providing a systematic quantification of accessibility and operability parameters to the boundaries of the posterior portion of the third ventricle (PTV) when applying an endoscopic-assisted paramedian supracerebellar infratentorial approach (EPSIA) are lacking. We performed an anatomical study and complemented our findings with surgical cases. Eight EPSIAs towards the PTV were performed in cadaveric specimens. Optimal approach angles (OA), surgical freedom (SF) and operability indexes (Oi) to the PTV boundaries were assessed. Additionally, a 54-year-old man and 33-year-old woman were operated on PTV tumors applying the EPSIA. Sagittal OA to ventricle's roof and floor was 36±1.4° and 25.5±3.5° respectively, axial OA to the ipsilateral and contralateral ventricle's wall were 9.5±1.3° and 28.5±1.6°. SF was maximal on the contralateral wall (121.2±19.3mm2), followed by the roof (112.7±18.8mm2), floor (106.6±19.2mm2) and ipsilateral wall (94.1±15.7mm2). SF was significantly lower along the ipsilateral compared the contralateral wall (P<0.01) and roof (P<0.05). Facilitated surgical maneuvers with multiangled exposure were possible up to 8.5±1.07mm anterior to ventricle's entrance, whereas surgical maneuvers were possible but difficult up to 15.25±3.7mm. Visualization of more anterior was possible up to a distance of 27±2.9mm, but surgical maneuvers were barely feasible. EPSIA enabled successful resection of both PTV tumors and postoperative course was uneventful. EPSIA can be effective for approaching the PTV, enabling surgery along all boundaries, but especially on its roof and contralateral wall. In the not-enlarged ventricle, surgical maneuvers are feasible up to the level of the Monro foramen, becoming more limited anteriorly.

Fourth ventricle roof angle as a measure of fourth ventricle bowing and a radiographic predictor of brainstem dysfunction in Chiari malformation type I.

Chiari malformation type I (CM-I) is a congenital and developmental abnormality that results in tonsillar descent 5 mm below the foramen magnum. However, this cutoff value has poor specificity as a predictor of clinical severity. Therefore, the authors sought to identify a novel radiographic marker predictive of clinical severity to assist in the management of patients with CM-I. The authors retrospectively reviewed 102 symptomatic CM-I (sCM-I) patients and compared them to 60 age-matched normal healthy controls and 30 asymptomatic CM-I (aCM-I) patients. The authors used the fourth ventricle roof angle (FVRA) to identify fourth ventricle "bowing," a configuration change suggestive of fourth ventricle outlet obstruction, and compared these results across all three cohorts. A receiver operating characteristic (ROC) curve was used to identify a predictive cutoff for brainstem dysfunction. Binary logistic regression was used to determine whether bowing of the fourth ventricle was more predictive of brainstem dysfunction than tonsillar descent, clival canal angle, or obex position in aCM-I and sCM-I patients. The FVRA had excellent interrater reliability (intraclass correlation 0.930, 95% CI 0.905-0.949, Spearman r2 = 0.766, p < 0.0001). The FVRA was significantly greater in the sCM-I group than the aCM-I and healthy control groups (59.3° vs 41.8° vs 45.2°, p < 0.0001). No difference was observed between aCM-I patients and healthy controls (p = 0.347). ROC analysis indicated that an FVRA of 65° had a specificity of 93% and a sensitivity of 50%, with a positive predictive value of 76% for brainstem dysfunction. FVRA > 65° was more predictive of brainstem dysfunction (OR 5.058, 95% CI 1.845-13.865, p = 0.002) than tonsillar herniation > 10 mm (OR 2.564, 95% CI 1.050-6.258, p = 0.039), although increasing age was also associated with brainstem dysfunction (OR 1.045, 95% CI 1.011-1.080, p = 0.009). A clival canal angle < 140° (p = 0.793) and obex below the foramen magnum (p = 0.563) had no association with brainstem dysfunction. The authors identified a novel radiographic measure, the FVRA, that can be used to assess fourth ventricular bowing in CM-I and is more predictive of brainstem dysfunction than tonsillar herniation. The FVRA is easy to measure, has excellent interrater variability, and can be a reliable universal radiographic measure. The FVRA will be useful in further describing CM-I radiographically and clinically by identifying patients more likely to be symptomatic as a result of brainstem dysfunction.

The third ventricle roof: an anatomical study using constructive interference in steady-state magnetic resonance imaging.

The third ventricle roof in vivo has been infrequently explored. The aim of the present study was to delineate the neurovascular structures relevant to the third ventricle roof using magnetic resonance (MR) imaging. A total of 78 patients were enrolled in the study. Following initial examinations with conventional MR sequences, the constructive interference in steady-state (CISS) sequence was performed in coronal sections on 67 patients and in sagittal sections on 11 patients. In the coronal sections, the fornices and internal cerebral veins were delineated in all 67 patients. The cross-sectional appearance and size of the fornices were variable, and the relationship between fornices presented as five different types. In 82% of patients, dominance of one relationship type was not found. The diameter of the internal cerebral veins (ICVs) was also variable, and the relationship between ICVs presented as four different types. In 70% of patients, dominance of one relationship type was not found. In 52% of patients, the lower layer of the third ventricle roof was identified as an inhomogeneous membranous structure. In the sagittal sections, the lower layer of the third ventricle roof was delineated as an inhomogeneous linear structure with variable slopes. The third ventricle roof appears highly variable in morphology. Visualization of the third ventricle roof using the CISS sequence may be useful for planning safe and effective surgical maneuvers around the region.

Endoscopic colloid cyst resection by puncture of the medial wall of lateral ventricle, posterior to the foramen of Monro

Abstract No consensus among neurosurgeons has been reached so far concerning optimal therapeutic strategy for colloids cysts, especially as these are non-invasive,slowgrowing, benign lesions. In symptomatic cases, endoscopic resection can be achieved as first intention when it seems to have a cyst containing fluid and there is ventriculomegaly. Cyst location and degree of superior distension of the third ventricle roof, associated with the emergence of Monro’s foramen can cause problems when using a rigid endoscope, the visualisation being impossible or difficult. Posterior interventricular foramen puncture may be helpful in such cases.

The distribution of arachnoid membrane within the velum interpositum

There is as yet little knowledge as to the arachnoid architecture within the velum interpositum. The aim of this study was to clarify the distribution of the arachnoid membrane within the velum interpositum and its relationship with the arachnoid envelope over the pineal region. In seven adult cadaver heads, histological sections of the third ventricle roof, stained with Masson's trichrome stains, were studied under light microscopy. Within the velum interpositum, there are two arachnoid layers. The dorsal layer of arachnoid membrane envelops the internal cerebral veins and fixes them to the surrounding tela choroidea as well as the ventral arachnoid layer. The ventral layer of arachnoid membrane is a direct anterior extension of the arachnoid envelope over the pineal region and covers the midline inferior layer of tela choroidea. Both arachnoid layers end near the foramen of Monro. The membranous roof of the third ventricle comprises two layers of the tela choroidea and two arachnoid layers. These two arachnoid layers are derived from the arachnoid envelope over the pineal region.

BULBAR COMPRESSION BY THE VERTEBRAL ARTERY: FOUR ATYPICAL CASES

Background: Symptomatic compression of the medulla oblongata and the pons by the vertebral artery is thought to be a rare condition; the literature pertaining to this condition consists merely of isolated case studies. Recent clinical experience suggests that this condition may be clinically under-appreciated and that patients with vascular compression of the brainstem are being misdiagnosed. Methods: Herein, we report on four surgical cases. All cases had a neuroradiological picture characterized by a megadolichovertebral artery pressing on the anterior bulbar surface. It should be emphasized that in all cases, the symptoms were initially attributed to associated pathologies (Chiari malformation, cervical spondylomyelopathy, cavernoma of the fourth ventricle, and hydrocephalus). Results: In the first few weeks after microvascular decompression of the bulb, the neurological picture of the patients showed clear signs of improvement with a considerable reduction in pre-operative symptoms. After 12 months, the patients with the Chiari malformation, cervical spondylomyelopathy and hydrocephalus continued to improve, whereas the patient suffering from a cavernoma of the fourth ventricle roof suffered partial symptom relapse. Conclusions: Currently, the major body of literature on compression of the medulla oblongata and the pons by the vertebral artery is sparse and consists only of "case reports". However, we believe that for patients displaying a series of symptoms indicating bulbar compression in the presence of a megadolichovertebral artery, the microvascular decompression of the brainstem should also be considered.

The Lengthening of a Giant Protein: When, How, and Why?

Subcommissural organ (SCO)-spondin is a giant glycoprotein of more than 5000 amino acids found in Vertebrata, expressed in the central nervous system and constitutive of Reissner's fiber. For the first time, in situ hybridization performed on zebrafish (Danio rerio) embryos shows that the gene encoding this protein is expressed transitionally in the floor plate, the ventral midline of the neural tube, and later in the diencephalic third ventricle roof, the SCO. The modular organization of the protein in Echinodermata (Strongylocentrotus purpuratus), Urochordata (Ciona savignyi and C. intestinalis), and Vertebrata (Teleostei, Amphibia, Aves and Mammalia) is also described. As the thrombospondin type 1 repeat motifs represent an increasingly large part of the protein during Deuterostomia evolution, the duplication mechanisms leading to this complex organization are examined. The functional significance of the particularly well-preserved arrangement of the series of SCO-spondin repeat motifs and thombospondin type 1 repeats is discussed.

A Cerebral Granular Cell Tumor in a Cat

A cerebral granular cell tumor is described in a 6-year-old, short-haired, female cat. The tumor was observed above the corpus callosum and completely infiltrating the third ventricle. Histologic examination revealed that the tumor was characterized by large cells containing densely packed intracytoplasmic granules and expressed psammoma body-like patterns and cholesterinic degeneration. Immunohistochemical analysis revealed granular neoplastic cells that were diffusely and strongly vimentin-positive, while they did not express cytokeratins, lysozyme, and synaptophysin. Based on morphologic and immunohistochemical findings, the tumor under study was considered to be of meningeal origin arising directly from the meninges or from meningeal elements scattered in the tela choroidea of the third ventricle roof.

Transcerebellomedullary fissure approach with special reference to the methods of dissecting the fissure

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. 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. 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.