The Influence of the Mandibular Chin Angle on the Occurrence of Mandibular Condylar Fracture: A Retrospective Study

Background. Condylar fractures are commonly associated with symphysis/parasymphysis fractures. Condylar fractures have been attributed to direct and indirect traumatic forces, the direction and magnitude of the forces, and the condylar anatomy. The chief aim of this study was to determine the association between the newly defined mandibular chin angle and the occurrence of condylar fractures. Materials and Methods. A retrospective study was conducted to analyze two-dimensional computed tomography (2D CT) scans of patients with a history of chin trauma. The outcome was a symphysis/parasymphysis fracture with or without fracture of the mandibular condyle. The Mediff InstaRISPACS web-based platform was used to measure the chin angle. The cerebral aqueduct of Sylvius in the corresponding 2D CT midsagittal image was the standard reference plane to measure the chin angle. The SPSS Version 20 (IBM Corp, Armonk, NY) was used for data analysis. Results. The sample size included 120 2D CT scans of patients with symphysis/parasymphysis fractures (60 associated with condylar fractures and 60 without condylar fractures). The mean chin angle in the group without condylar fracture was 133.35 ± 3.87°, which was approximately 15° lesser than in the condylar fracture group (mean, 148.56 ± 5.49°), and these findings were statistically significant P < 0.05 . Conclusion. Individuals with a high chin angle are potentially at a higher risk of sustaining associated condylar fractures.

Computational Modeling and Simulation of Stenosis of Aqueduct of Sylvius Due to Brain Tumor

Background: Stenosis of cerebral aqueduct (CA) is featured in many studies related to elevated intracranial cerebral pressures (ICP). It also presents a challenging situation to clinicians. Compressive forces play a lead role in pathological situations like tumor presence and hence can cause obstruction to the flow of cerebrospinal fluid (CSF). Due to this barrier, excessive retention of CSF in ventricles can occur. This in turn could contribute to increased pressure gradients inside the cranium. In literature, most of the numerical models are restricted to modeling the CSF flow by considering ventricle walls as rigid material unlike its behavior a deformable character. This paper, therefore, addresses the same from a holistic perspective by taking into consideration the dynamics of the flexible character of the ventricular wall. This adds to the novelty of this work by reconstructing an anatomically realistic ventricular wall behavior. To do this, the authors aim to develop a computational model of stenosis of CA due to brain tumor by invoking a fluid-structure interaction (FSI) method. The proposed 3D FSI model is simulated under two cases. First, simulation of pre-stenosis case with no interaction of tumor forces and secondly, a stenosis condition together-with dynamic interaction of tumor forces. Results: Comparing the forces with and without tumor reveals a marked obstruction of CSF outflow post third ventricle and the cerebral aqueduct. Not only this but a drastic rise of CSF velocity from 21.2 mm/s in pre-stenosis case to 54.1 mm/s stenosis case is also observed along with a net deformation increase of 0.144 mm on walls of ventricle. Conclusions: This is a significant contribution to brain simulation studies for pressure calculations, wherein the presence of tumors is a major concern.

Parasagittal Dural Space and Cerebrospinal Fluid (CSF) Changes Across the Lifespan in Healthy Adults: Implications for Glymphatic Flow

Background: Recent studies have suggested the importance of a glymphatic clearance pathway for brain parenchymal metabolic waste products. One fundamental but relatively under-explored component of this pathway is the anatomic region surrounding the superior sagittal sinus, which has been hypothesized to encompass lymphatic vessels. This so-called parasagittal dural (PSD) space likely plays a physiologically significant role at the distal intracranial component of the human glymphatic circuit, yet owing to the relative novelty of this discovery, fundamental gaps persist in our knowledge of how this space changes with normal aging and intracranial bulk fluid transport. Methods: We tested the hypotheses that volumetric magnetic resonance imaging (MRI) measures of the PSD space (i) are directly related to cerebrospinal fluid (CSF) flow at the cerebral aqueduct, and (ii) increase with age. Healthy participants (n=62; age range = 20-83 years) provided informed, written consent and multi-modal 3 Tesla MRI was performed including phase contrast assessment of the CSF flow through the aqueduct of Sylvius, T1-weighted and T2-weighted MRI for tissue volume and PSD assessment. Standard anatomical and cognitive testing were applied to confirm inclusion criteria. PSD volume was extracted using a recently validated neural networks algorithm. Non-parametric regression models were applied to evaluate how PSD volume related to tissue volume and age cross-sectionally, and separately how PSD volume related to CSF flux (significance criteria: two-sided p<0.05). Results: A significant enlargement of PSD volume in relation to normal aging (p<0.001, Spearman’s- =0.6), CSF volume (p<0.001, Spearman’s- =0.6) and bulk CSF flux through the aqueduct of Sylvius (anterograde and retrograde, p<0.001) were observed. The elevation in PSD volume was not significantly related to changes in tissue volume (p=0.11 and p=0.24 for gray and white matter, respectively). Findings are consistent with PSD volume increasing with age and bulk CSF flux.Conclusions: The findings of this study are two folds, first they highlight the feasibility of quantifying PSD volume non-invasively in vivo in humans using machine learning and non-contrast MRI. Second, that PSD volume increases with age, and relates to bulk CSF volume and flux. Values reported should provide useful normative ranges for how PSD volume adjusts with age, which will serve as a necessary pre-requisite for comparisons to persons with neurodegenerative disorders.

Magnetic Resonance Morphometry of Normal Cerebral Aqueduct in South Indian Population

Introduction Cerebral aqueduct (of Sylvius) connects the third and fourth ventricles of the brain, and the shape of the aqueduct varies. The aim of the study is to assess the morphometry of the cerebral aqueduct in normal south Indian adult population and to look for pattern by shape, if any. Materials and Methods One hundred and fifty normal brain MR images (75 males and 75 females) using 3D heavily T2-weighted sequence were analyzed for various normal parameters of cerebral aqueduct. Mean and standard deviation were calculated. Based on the shape of the aqueduct, an attempt was made to classify them. Unpaired t-test was used to assess any significant difference between age groups and gender. The intraclass coefficient correlation was used to analyze the interobserver variability. Results The mean value of the length of the cranial and caudal part of aqueduct in males were 0.69 cm and 0.86 cm and in females 0.65 cm and 0.80 cm, respectively. The length was more in males, and it was statistically significant (p = 0.006 and 0.02). There are four types of cerebral aqueduct based on shape. Conclusion MRI is considered as the investigation of choice for preoperative planning of brain operative procedures. The MR morphometric evaluation of cerebral aqueduct provides precise knowledge about the anatomy and may be of help in the diagnosis and treatment by endoscopic neurosurgery.

Rigid endoscopic surgery of brainstem cavernous malformation on the cerebral aqueduct. Case report

Cavernous angiomas (malformations) of the brain occur in 0.5% of the population. Most of them are asymptomatic, but due to their anatomical features, namely escape of blood into surrounding tissues, significant neurological symptoms can occur. The deep location of cavernous angiomas in the area of cerebral aqueduct makes surgical intervention difficult. Microsurgical approaches are the gold standard in removal of cavernous angiomas, but they are associated with certain surgical risks in the formation of the surgical corridor. Cavernous malformations in the cerebral aqueduct are a rare subtype. Due to anatomical localization and concomitant obstructive hydrocephalus ІІІ and lateral ventricles, they can be removed by endoscopic frontal transcortical transventricular approach. A 59-year-old patient was diagnosed with cavernous angioma of the brainstem (in the area of cerebral aqueduct) with hemorrhage and the formation of obstructive hydrocephalus ІІІ and lateral ventricles. The operation was performed: removal of the cavernous angioma in the area of cerebral aqueduct by endoscopic frontal transcortical transventricular approach on the right. Additionally, a triventriculocisternostomy was performed. Osteoplastic trepanation with centering at the Kocher’s point in size of 4 × 4 cm and the formation of a free bone flap was performed. The dura mater is cut in an H-shape. Approach to the anterior horn of the right lateral ventricle was performed. An intracerebral retractor was inserted into the anterior horn of the right lateral ventricle. Transforaminal approach to the tuber cinereum was performed - a triventriculocisternostomy was performed. Transforaminal approach to the cerebral aqueduct was performed and the cavernous angioma of the brainstem was removed. In the postoperative period, the patient had a slight deterioration in short-term memory, which regressed 2 weeks after surgery, an increase in oculomotor disorders, in particular persistent diplopia due to moderate paresis of the left oculomotor nerve. Three months after the operation, magnetic resonance imaging of the brain with intravenous contrast enhancement was performed. There are no signs of cavernous angioma. After the operation of frontal transcortical transventricular removal of cavernous angioma in the area of cerebral aqueduct, the compression of the latter was eliminated. Occlusive hydrocephalus regressed, the size of the ventricles decreased. Endoscopic frontal transcortical transventricular approach allows reaching the area of cerebral aqueduct in a less traumatic and minimally invasive manner. This technique is effective due to the low risk of surgical approach complications.

Parkinsonism secondary to ventriculoperitoneal shunt in a patient with hydrocephalus

Background: Parkinsonism secondary to the treatment of obstructive hydrocephalus due to stenosis of the cerebral aqueduct, with implantation of a ventricular peritoneal (VP) shunt is a rare complication, still poorly described and disseminated in the literature. Case Description: A 38-year-old male presented a history of moderate-intensity daily headache, which deteriorated 2 months before admission, with no changes in the neurological examination. Magnetic resonance imaging showed hypertensive hydrocephalus associated with cerebral aqueduct stenosis. A VP shunt was performed, an adjustable pressure valve was successfully inserted, and he was discharged asymptomatic. However, months later, he progressed with important symptoms of hypo- and hyper-drainage, which persisted after valve pressure adjustments and even its exchange, culminating into an endoscopic third ventriculostomy (ETV). But soon after, severe Parkinsonian syndrome appeared. Therapy with levodopa and bromocriptine was initiated, revealing a slow response initially but good evolution within 6 months. At present, he presents low-intensity residual tremor, which is well controlled with medications, and has regained independence for daily activities, with minimal motor limitation and no cognitive changes. Conclusion: There is still no mechanism that explains the occurrence of Parkinsonian syndrome in these cases. It is suggested that the rostral portion of the midbrain was injured due to abrupt changes in the transtentorial gradient pressure after the ventricular shunt, along with various adjustments in the valve pressure. ETV and early introduction of levodopa therapy in patients who developed postventriculoperitoneal shunt Parkinsonism seems to be the most effective combination, with satisfactory clinical response in the medium/long term.

CSF Secretion Is Not Altered by NKCC1 Nor TRPV4 Antagonism in Healthy Rats

Background: Cerebrospinal fluid (CSF) secretion can be targeted to reduce elevated intracranial pressure (ICP). Sodium-potassium-chloride cotransporter 1 (NKCC1) antagonism is used clinically. However, supporting evidence is limited. The transient receptor potential vanilloid-4 (TRPV4) channel may also regulate CSF secretion and ICP elevation. We investigated whether antagonism of these proteins reduces CSF secretion. Methods: We quantified CSF secretion rates in male Wistar rats. The cerebral aqueduct was blocked with viscous mineral oil, and a lateral ventricle was cannulated. Secretion rate was measured at baseline and after antagonist administration. Acetazolamide was administered as a positive control to confirm changes in CSF secretion rates. Results: Neither NKCC1, nor TRPV4 antagonism altered CSF secretion rate from baseline, n = 3, t(2) = 1.14, p = 0.37, and n = 4, t(3) = 0.58, p = 0.6, respectively. Acetazolamide reduced CSF secretion by ~50% across all groups, n = 7, t(6) = 4.294, p = 0.005. Conclusions: Acute antagonism of NKCC1 and TRPV4 proteins at the choroid plexus does not reduce CSF secretion in healthy rats. Further investigation of protein changes and antagonism should be explored in neurological disease where increased CSF secretion and ICP are observed before discounting the therapeutic potential of protein antagonism at these sites.

Diagnostic accuracy of sagittal TSE-T2W, variable flip angle 3D TSE-T2W and high-resolution 3D heavily T2W sequences for the stenosis of two localizations: the cerebral aqueduct and the superior medullary velum

Objectives: This study aimed to investigate the accuracy of conventional sagittal turbo spin echo T2-weighted (Sag TSE-T2W), variable flip angle 3D TSE (VFA-3D-TSE) and high-resolution 3D heavily T2W (HR-3D-HT2W) sequences in the diagnosis of primary aqueductal stenosis (PAS) and superior medullary velum stenosis (SMV-S), and the effect of stenosis localization on diagnosis. Methods: Seventy-seven patients were included in the study. The diagnosis accuracy of the HR-3D-HT2W, Sag TSE-T2W and VFA-3D-TSE sequences, was classified into three grades by two experienced neuroradiologists: grade 0 (the sequence has no diagnostic ability), grade 1 (the sequence diagnoses stenosis but does not show focal stenosis itself or membrane formation), and grade 2 (the sequence makes a definitive diagnosis of stenosis and shows focal stenosis itself or membrane formation). Stenosis localizations were divided into three as Cerebral Aquaduct (CA), superior medullary velum (SMV) and SMV+CA. In the statistical analysis, the grades of the sequences were compared without making a differentiation based on localization. Then, the effect of localization on diagnosis was determined by comparing the grades for individual localizations. Results: In the sequence comparison, grade 0 was not detected in the VFA-3D-TSE and HR-3D-HT2W sequences, and these sequences diagnosed all cases. On the other hand, 25.4% of grade 0 was detected with the Sag TSE-T2W sequence (P<0.05). Grade 1 was detected by VFA-3D-TSE in 23% of the cases, while grade 1 (12.5%) was detected by HRH-3D-T2W in only one case, and the difference was statistically significant (P<0.05). When the sequences were examined according to localizations, the rate of grade 0 in the Sag TSE-T2W sequence was statistically significantly higher for the SMV localization (33.3%) compared to CA (66.7%) and SMV+CA (0%) (P<0.05). Localization had no effect on diagnosis using the other sequences. Conclusion: In our study, we found that the VFA-3D-TSE and HR-3D-HT2W sequences were successful in the diagnosis of PAS and SMV-S contrary to the Sag TSE-T2W sequence.