Sylvian Fissure Research Articles

Unpacking the Tibial Tubercle–Trochlear Groove Distance: Evaluation of Rotational Factors, Trochlear Groove and Tibial Tubercle Position, and Role of Trochlear Dysplasia

Background: The tibial tubercle to trochlear groove (TT-TG) distance is often utilized for determining the surgical treatment for patients with patellar instability (PI). It is thought to directly represent the position of the TT on the tibia. Recent work has shown that the measurement of the TT-TG distance is multifactorial. Purpose: To investigate the relationship between relative tibial external rotation (rTER) and trochlear dysplasia (TD), as well as the location of the TG and TT in patients with and without PI, and to correlate these and other anatomic measurements with the TT-TG distance. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 89 patients with PI who underwent magnetic resonance imaging were identified with 92 matched control patients. A standardized measurement protocol on axial magnetic resonance imaging determined rTER, the proximal and distal TG lateralization (pTGL and dTGL, respectively) ratios, and the TT lateralization (TTL) ratio. Other measures of interest included the lateral trochlear inclination angle, sulcus angle, and lateral patellar inclination angle. Univariate regression was used to determine the associations of TD (lateral trochlear inclination angle, sulcus angle) with rTER and the TG position, and multivariate regression was used to model associations among all the variables with the proximal and distal TT-TG distances. Results: rTER was significantly higher in the study group (P < .001), and univariate regression showed a significant association between dysplasia measures and rTER (P < .001). The pTGL ratio was lower in the study group (P = .025), but there was no difference in the dTGL ratio (P = .090) or the TTL ratio (P = .098) between the groups. There were no associations between dysplasia measures and the pTGL and dTGL ratios (P > .05). Multivariate regression showed that the proximal TT-TG distance is predicted by the sulcus angle, pTGL ratio, rTER, and TTL ratio (P < .05) and that the distal TT-TG distance is predicted by the lateral patellar inclination angle, dTGL ratio, sulcus angle, rTER, and TTL ratio (P < .05). Conclusion: rTER had a significant association with TD. The position of the proximal TG was more medial in patients with PI. There was no significant difference in the TTL ratio between patients with and without PI. The TT-TG distance was associated with multiple anatomic measures and was not solely predicated on the position of the TT.

The unique features of middle cranial fossa and Sylvian fissure arachnoid cysts in children: MRI evaluation.

The purpose of the study is to evaluate MRI findings of middle fossa arachnoid cysts in children according to Galassi classification and determine the differences between types and to assess the morphological changes in cysts during follow-up imaging. MR images of 266 middle fossa arachnoid cysts of 255 pediatric patients were evaluated by two experienced radiologists retrospectively. MRI features including the sidedness of the cyst, Galassi type, parenchymal compression findings (cortical flattening and white matter compression), bone remodeling, and midline shift were evaluated on axial T2- and T1-weighted images. Follow-up MRI and available CSF flow MR imaging data were evaluated for change in cyst size and cisternal connections, respectively. The most common type was type 1 according to Galassi classification. The accompanying bone remodeling and white matter compression had a higher incidence in Galassi type 2 and 3 groups than Galassi type 1. Mean age of patients with bone remodeling and white matter compression was significantly higher in patients with Galassi type 1. All patients with cyst enlargement were younger than 2years of age, and all of them were Galassi type 1. Cisternal connection was demonstrated in 7 patients. While parenchymal compression and bone remodeling are expected findings in Galassi type 2 and 3 cysts, these features can also be seen in smaller Galassi type 1 cysts, regardless of size. Most of the middle fossa arachnoid cysts remain stable on follow-up imaging, and the increase in size is not an expected finding, especially in older children.

The relationship between reading abilities and the left occipitotemporal sulcus: A dual perspective study

Reading activates a region within the left lateral occipitotemporal sulcus (OTS) known as the ‘visual word form area’ (VWFA). While several studies have investigated the impact of reading on brain structure through neuroplastic mechanisms, it has been recently suggested that individual differences in the pattern of the posterior OTS may predict reading skills in adults. In the present study, we first examined whether the structure and morphology and the anatomical connectivity of the left OTS are associated to reading ability. Second, we explored whether reading skills are predicted by the pattern of the left OTS. We found that reading skills were positively associated with increased connectivity between the left OTS and a network of reading-related regions in the left hemisphere. On the other hand, we did not observe an association between the pattern of the left OTS and reading skills. Finally, we found evidence that the morphology and the connectivity of the left OTS are correlated to its sulcal pattern.

Usefulness of the Multimodal Fusion Image for Visualization of Deep Sylvian Veins.

The preoperative assessment of cerebral veins is important to avoid unexpected cerebral venous infarction in the neurosurgical setting. However, information is particularly limited regarding deep Sylvian veins, which occasionally disturb surgical procedures for cerebral anterior circulation aneurysms. The predictability of detecting deep Sylvian veins and their tributaries using a modern multimodal fusion image was aimed to be evaluated. Moreover, 51 patients who underwent microsurgery for unruptured cerebral aneurysms with Sylvian fissure dissection were retrospectively reviewed. The visualization of the four components of the deep Sylvian veins in conventional computed tomography (CT) venography and multimodal fusion images was evaluated. To compare the detection accuracy among these radiological images, the sensitivity and specificity for the detection of each of the four venous structures were calculated in comparison with those of intraoperative inspections. The kappa coefficients were also measured and the inter-rater agreement for each venous structure in each radiological image was examined. In all veins, the multimodal fusion image exhibited a high detection rate without statistical difference from intraoperative inspections (P = 1.0). However, CT venography exhibited a low detection rate with a significant difference from intraoperative inspections in the common vertical trunk (P = 0.006) and attached vein (P = 0.008). The kappa coefficients of the fusion image ranged from 0.73 to 0.91 and were superior to those of CT venography for all venous structures. This is the first report to indicate the usefulness of a multimodal fusion image in evaluating deep Sylvian veins, especially for the detection of nontypical, relatively small veins with large individual variability.

Effects of individualized brain anatomies and EEG electrode positions on inferred activity of the primary auditory cortex.

Due to its high temporal resolution and non-invasive nature, electroencephalography (EEG) is considered a method of great value for the field of auditory cognitive neuroscience. In performing source space analyses, localization accuracy poses a bottleneck, which precise forward models based on individualized attributes such as subject anatomy or electrode locations aim to overcome. Yet acquiring anatomical images or localizing EEG electrodes requires significant additional funds and processing time, making it an oftentimes inaccessible asset. Neuroscientific software offers template solutions, on which analyses can be based. For localizing the source of auditory evoked responses, we here compared the results of employing such template anatomies and electrode positions versus the subject-specific ones, as well as combinations of the two. All considered cases represented approaches commonly used in electrophysiological studies. We considered differences between two commonly used inverse solutions (dSPM, sLORETA) and targeted the primary auditory cortex; a notoriously small cortical region that is located within the lateral sulcus, thus particularly prone to errors in localization. Through systematical comparison of early evoked component metrics and spatial leakage, we assessed how the individualization steps impacted the analyses outcomes. Both electrode locations as well as subject anatomies were found to have an effect, which though varied based on the configuration considered. When comparing the inverse solutions, we moreover found that dSPM more consistently benefited from individualization of subject morphologies compared to sLORETA, suggesting it to be the better choice for auditory cortex localization.

Measures of intracranial compartments in acute intracerebral haemorrhage: data from the Rapid Intervention with Glyceryl Trinitrate in Hypertensive Stroke-2 Trial (RIGHT-2)

Background and purposeIntracerebral haemorrhage volume (ICHV) is prognostically important but does not account for intracranial volume (ICV) and cerebral parenchymal volume (CPV). We assessed measures of intracranial compartments in acute...

Regional Neuroanatomic Effects on Brain Age Inferred Using Magnetic Resonance Imaging and Ridge Regression.

The biological age of the brain differs from its chronological age (CA) and can be used as biomarker of neural/cognitive disease processes and as predictor of mortality. Brain age (BA) is often estimated from magnetic resonance images (MRIs) using machine learning (ML) that rarely indicates how regional brain features contribute to BA. Leveraging an aggregate training sample of 3 418 healthy controls (HCs), we describe a ridge regression model that quantifies each region's contribution to BA. After model testing on an independent sample of 651 HCs, we compute the coefficient of partial determination R¯p2 for each regional brain volume to quantify its contribution to BA. Model performance is also evaluated using the correlation r between chronological and biological ages, the mean absolute error (MAE ) and mean squared error (MSE) of BA estimates. On training data, r=0.92, MSE=70.94 years, MAE=6.57 years, and R¯2=0.81; on test data, r=0.90, MSE=81.96 years, MAE=7.00 years, and R¯2=0.79. The regions whose volumes contribute most to BA are the nucleus accumbens (R¯p2=7.27%), inferior temporal gyrus (R¯p2=4.03%), thalamus (R¯p2=3.61%), brainstem (R¯p2=3.29%), posterior lateral sulcus (R¯p2=3.22%), caudate nucleus (R¯p2=3.05%), orbital gyrus (R¯p2=2.96%), and precentral gyrus (R¯p2=2.80%). Our ridge regression, although outperformed by the most sophisticated ML approaches, identifies the importance and relative contribution of each brain structure to overall BA. Aside from its interpretability and quasi-mechanistic insights, our model can be used to validate future ML approaches for BA estimation.

AN UNUSUAL CASE OF SUBACUTE BACTERIAL ENDOCARDITIS PRESENTING WITH CATASTROPHIC SUBARACHNOID HEMORRHAGE

AN UNUSUAL CASE OF SUBACUTE BACTERIAL ENDOCARDITIS PRESENTING WITH CATASTROPHIC SUBARACHNOID HEMORRHAGE

Comparison of Midterm Survivorship, Radiographic, and Clinical Outcomes of the INBONE II and Salto Talaris Total Ankle Arthroplasty Systems

Category: Ankle; Ankle Arthritis Introduction/Purpose: Prior studies on the INBONE II and Salto Talaris total ankle arthroplasty (TAA) systems have reported favorable outcomes for both implants. However, it is unclear whether there were significant differences in survivorship between and if this led to subsequent differences in clinical or radiographic outcomes the two. To date, no similar comparisons have been done in the literature, although it is important to understand the clinically relevant distinctions between these more recent third generation TAA systems. This retrospective study aimed to compare the midterm differences between INBONE II and Salto Talaris TAA. Methods: Between 2007 and 2015, 44 INBONE II consecutive cases and 85 Salto Talaris consecutive cases had minimum 5-year clinical and radiographic follow-up. The endpoints for survivorship were revision, defined as removal or replacement of any implant component, and reoperation, defined as a non-revision surgery. Preoperative and midterm postoperative Foot and Ankle Outcome Score (FAOS), which has been validated for ankle osteoarthritis, and radiographic measures including tibiotalar alignment (TTA) and medial distal tibial angle (MDTA) were compared. Talar inclination angle (TIA) was compared to examine subsidence and cysts were examined for osteolysis. Average midterm follow-up for these patients was 6.4 +- 1.1 (range, 5-9) years for the INBONE II group, and 7 +- 1.9 (range, 5-12.7) years for the Salto Talaris group. Results: Survivorship to revision was 97.6% (95% CI, 93.1%-100%) for the INBONE II group and 97% (95% CI, 93%-100%) for the Salto Talaris group (P = .93). Survivorship to reoperation was significantly different; 95.5% for the INBONE II and 76.4% for Salto Talaris (P = .021) (Figure 1). All FAOS improved postoperatively (P &lt; .001), although the INBONE II had superior postoperative scores in pain (P = .01), symptoms (P = .004), and sports activity (P = .02). There were no differences between groups in postoperative radiographic alignment, despite the INBONE group having greater preoperative deformity. There was one instance of subsidence in each group and similar rates of cyst occurrence across the INBONE II (18.2%) and Salto Talaris (21.2%) groups. Conclusion: Although both implants had similar longevity and postoperative alignment, the INBONE II resulted in greater clinical improvement and fewer reoperations than the Salto Talaris at midterm follow-up. The majority of reoperations in the Salto Talaris group were due to gutter impingement. The contrasting reoperation rates between groups may be explained by differences in implant design and technique, such as rotational malpositioning of the talus and the lateral sulcus design of the Salto Talaris. Additionally, the INBONE II TAA system was able to correct deformity and improve clinical outcomes even though this cohort exhibited greater preoperative deformity.

Distribution and progression of cerebral amyloid angiopathy in early-onset V30M (p.V50M) hereditary ATTR amyloidosis

Background Cerebral amyloid angiopathy (CAA) is becoming the most common and serious complications in long-lived hereditary ATTR amyloidosis patients. It is therefore imperative to elucidate the characteristics of ATTR-type CAA and develop useful biomarkers. Methods We enrolled 34 ATTRv amyloidosis patients with the V30M (p.V50M) variant for analysis with three-dimensional stereotactic surface projection z score imaging of Pittsburgh compound B (PiB)-PET. Results Eight patients exhibited central nervous system (CNS) symptoms. Seven patients suffered transient focal neurologic episodes, and 2 patients each experienced cerebellar haemorrhages or cognitive decline. The amount of 11C-PiB accumulation increased as a function of disease duration. 11C-PiB-PET abnormalities were seen at 8 years from onset and were associated with CNS manifestations from 12 years. The annual increase rate of the standardised uptake value ratio (SUVR) in female patients was significantly higher than in male patients. CNS amyloid deposition started in the upper middle surface of the cerebellar cortex, and then spread out over the entire surface of the cerebellum, Sylvian fissure, and anterior part of the longitudinal fissure of the cerebrum. Conclusions PiB-PET is a useful biomarker for the early detection and treatment evaluation of ATTR-type CAA. Female gender is associated with more rapid progression of ATTR-type CAA.

Neurosurgical anatomy of the insula and Sylvian fissure in gliomas: literature review and personal experience. The second report. Veins

Insular gliomas account for 25% of all low-grade and 10% of high-grade gliomas. Neurosurgical treatment of insular gliomas involves achieving the maximum possible volume of tumor removal while ensuring high quality of life. The anatomical proximity of functionally important brain structures and the involvement of important insular arteries and veins limits the possibility of radical removal of tumors. The key to the effectiveness of surgical intervention in insular gliomas is the selection and implementation of adequate surgical access surgical access. The most commonly used approach to insular gliomas is transsylvian-transinsular. The implementation of this approach is largely determined by the individual characteristics of the venous system of the sylvian fissure, since it is characterized by extreme anatomical variability in particular, the type of outflow direction dominance, the number of veins, their size, type of branching, drainage, collateral connections. The review presents data on the informativeness of modern methods of instrumental research in the assessment of the venous system of the sylvian fissure and insula with the aim of planning surgery for insular gliomas. Methods of preserving venous collectors of the sylvian fissure and possible complications associated with the exclusion of draining veins from the circulation are described.

Effectiveness of multiple endoscopic fenestrations for the treatment of Sylvian fissure arachnoid cysts: a multicenter study.

Arachnoid cysts are usually asymptomatic lesions. However, they can sometimes cause intracranial hypertension, headache, seizures, focal neurological deficits, and bleeding. The most commonly used surgical techniques are microsurgical cyst fenestration/excision/drainage, cyst shunting, and endoscopic procedures. We aimed to investigate the success of different surgical techniques. Between 2000 and 2021, patients with Sylvan fissure arachnoid cysts who received treatment via an endoscopic approach chosen as the first-line treatment in three centers were enrolled. All case notes and radiological studies were evaluated retrospectively. The study included 131 (female, n = 28; male, n = 103) patients with a mean age of 87.04 ± 66.76 (range, 0-216) months. Of the patients, 25 had Galassi type II left-sided arachnoid cysts, 33 had Galassi type II right-sided arachnoid cysts, 40 had Galassi type III left-sided arachnoid cysts, and 32 had Galassi type III right-sided arachnoid cysts. No difference was found between patients who underwent single and multiple fenestrations in terms of Galassi type, side, clinical outcome, and cyst size (p > 0.05). On the contrary, the rate of additional surgical intervention was lower in patients with multiple fenestrations than in those with single fenestration (36.10% vs. 5.30%; p < 0.001). Endoscopic fenestration of Sylvian fissure arachnoid cysts is a good alternative to open surgery or cystoperitoneal shunting, and the number of fenestrations made during this surgery decreases the need for a second surgical procedure.

Treatment and outcomes of non-aneurysmal perimesencephalic subarachnoid haemorrhage: A 5 year retrospective study in a tertiary care centre

PurposePerimesencephalic Subarachnoid Haemorrhage (PMSAH) is an uncommon type of SAH. Severity of PMSAH can be graded by the presence of blood in the Sylvian fissure. No study compares the outcomes from PMSAH with blood present or absent in the Sylvian fissure. Furthermore, the use of Nimodipine lacks evidence base in PMSAH. We investigated whether continuing Nimodipine to 21 days in PMSAH with or without blood in the Sylvian fissure made any significant difference to patient outcome. MethodsRetrospective study of 93 cases admitted to tertiary centre from 2016 to 2020. We compared prevalence of cases with blood in Sylvian fissure, and analysed outcomes including complications and changes to patient modified rankin scale (MRS). We also audited use of Nimodipine in these cases and analysed whether Nimodipine made any significant difference in preventing complications. Results91 % of PMSAH were grade 1, 24 cases (26 %) had blood in the Sylvian fissure. Sylvian fissure positive (Sylvian-positive) cases were statistically significantly more likely to have higher rates of complication compared to Sylvian fissure negative (Sylvian-negative) cases. Our centre stopped Nimodipine 56 % of the time in Sylvian-negative cases and 45 % of the time in Sylvian-positive cases. There was no statistically significant difference in outcomes when Nimodipine was continued to 21 days or ceased after negative angiogram; this result extended to both Sylvian-positive and Sylvian-negative subgroups when directly comparing Sylvian-positive cases with each other and Sylvian-negative cases likewise. DiscussionSylvian-positive cases have a significantly higher rate of complication, as well as an increase in MRS. This may be because of the inflammatory properties of haemoglobin in the subarachnoid space post-bleed. Furthermore, acknowledging the limitations of our retrospective data, we did not find a statistically significant difference in continuing Nimodipine to 21 days with relation to PMSAH outcomes in all subgroups.

Impact of dome projection on operative steps during clipping of a ruptured pure posteriorly directed posterior communicating artery aneurysms

Background: Ruptured posterior communicating artery (PCoA) aneurysms are common; they usually present with subarachnoid haemorrhage (SAH) and oculomotor nerve palsy. The aneurysmal dome projection may influence the safety access and aneurysmal neck clipping. Here, we discuss additional intraoperative steps that may be required to widen the surgical field to ensure safe surgical clipping of a rupture pure posteriorly directed PCoA aneurysm. Case description: A previously healthy 38-year-old male reported sudden severe headache and disturbed level of consciousness with a Glasgow coma scale (GCS) of 13. His initial computed tomography (CT) scan of the head showed SAH in the basal cistern. 3D-constructed CT angiography (CTA) revealed a left pure posteriorly directed PCoA aneurysm. In the surgery, through the left pterional approach, all intraoperative steps were carried out. Additional steps were performed as well. Three additional intraoperative steps were contemplated because a pure posteriorly directed PCoA aneurysm is not well appreciated and is often hidden behind the supra cliniold internal carotid artery (ICA). First, the extension of Sylvian fissure dissection to include the distal part and the proximal. Second, temporal pole mobilization is performed by cutting small anterior temporal veins. Third, a brain retractor is placed on the temporal lobe to gently tract the superficial part of the lobe. All these steps widened the surgical corridor to ensure the aneurysm's safe clipping. Conclusion: Surgical clipping is influenced by the aneurysmal dome projection. In a ruptured pure posteriorly directed PCoA aneurysm, further intraoperative steps may facilitate complete access and safe clipping of the aneurysm.

Fetal brain biometry and cortical development in congenital heart disease: A prospective cross sectional study.

To evaluate brain biometry and cortical development by neurosonography in fetuses with congenital heart defect (CHD) and evaluate differences among different type of CHD. In a prospective cross sectional study singleton fetus with CHD were matched with controls and grouped into two categories according to the predicted severity of cerebral arterial oxygen deficit induced by the CHD: Group A mildly reduced or normal and Group B moderately to severely reduced. Neurosonography was done at 30-33 weeks to obtain measurements of corpus callosum (CC), cerebellar vermis (CV), Sylvian fissure (SF) insula, parieto-occipital fissure (POF), and calcarine sulci fissures (CSF). All the neurosonographic parameters were adjusted by head circumference (HC). A total of 78 fetuses with CHD (group A 30; group B 48) and 80 matched controls form uncomplicated pregnancies were considered. CHD fetuses have significantly smaller CC, CV, SF, and POF and bigger insula when compared to control fetuses. These differences are more marked in group B fetuses. These differences remained significant after correction for HC values. Fetuses with CHD have an impaired cortical development and these variations are more evident in those with a predicted lower oxygen delivery to the brain.

Cerebral venous sinus thrombosis presenting with subarachnoid hemorrhage: a series of 11 cases.

Cerebral venous sinus thrombosis (CVST) is a rare cerebrovascular disease with a wide spectrum of clinical manifestations. The aim of this study is to assess the presence of subarachnoid hemorrhage (SAH) in the context of CVST and to present its epidemiological, clinical and radiological/laboratory aspects. Between October 2012 and October 2019, 43 patients with CVST were reviewed. Eleven (25.58%) cases presented SAH. A quarter of the patients evaluated with CVST had SAH. There were 9 women (81.82%) and 2 men, with a mean age at presentation of 37.7years (range 28-49). The most common risk factor was the use of oral contraceptives and the most prevalent symptom was headache. Both sinuses, the superior sagittal sinus and the transverse sinus, were the most affected. There was no isolated involvement of the cortical vein. The SAH was limited to some sulci of cerebral convexity in 8 cases (72.73%). In one case, the location of SAH was in the cerebellum and in two cases in the Sylvian fissure. In two cases, there was an evolution to venous infarction; and in three cases, intraparenchymal hemorrhage was present. Seven patients (63.64%) improved considerably with anticoagulation after 6months of treatment. This series found that 25.58% of patients with CVST had SAH. It is the highest incidence described in the literature so far. Findings of SAH located in the cerebral convexities, without affecting the base cisterns, should always lead to the suspicion of CVST.

Distinct volumetric features of cerebrospinal fluid distribution in idiopathic normal-pressure hydrocephalus and Alzheimer’s disease

ObjectiveThe aims of the study were to measure the cerebrospinal fluid (CSF) volumes in the lateral ventricle, high-convexity subarachnoid space, and Sylvian fissure region in patients with idiopathic normal-pressure hydrocephalus (INPH) and Alzheimer’s disease (AD), and to evaluate differences in these volumes between INPH and AD groups and healthy controls.MethodsForty-nine INPH patients, 59 AD patients, and 26 healthy controls were imaged with automated three-dimensional volumetric MRI.ResultsINPH patients had larger lateral ventricles and CSF spaces of the Sylvian fissure region and smaller high-convexity subarachnoid spaces than other groups, and AD patients had larger lateral ventricles and CSF spaces of the Sylvian fissure region than the control group. The INPH group showed a negative correlation between lateral ventricle and high-convexity subarachnoid space volumes, while the AD group showed a positive correlation between lateral ventricle volume and volume for CSF spaces of the Sylvian fissure region. The ratio of lateral ventricle to high-convexity subarachnoid space volumes yielded an area under the curve of 0.990, differentiating INPH from AD.ConclusionsAssociations between CSF volumes suggest that there might be different mechanisms between INPH and AD to explain their respective lateral ventricular dilations. The ratio of lateral ventricle to high-convexity subarachnoid space volumes distinguishes INPH from AD with good diagnostic sensitivity and specificity. We propose to refer to this ratio as the VOSS (ventricle over subarachnoid space) index.

A New Classification of the Anatomical Variations of Labbé's Inferior Anastomotic Vein.

(1) Background: The inferior anastomotic vein of Labbé (LV) courses on the temporal lobe, from the sylvian fissure towards the tentorium cerebelli and finishes at the transverse sinus (TS). The importance of the LV topography is related to skull base neurosurgical approaches. Based on the hypothesis of the existence of as yet unidentified anatomical possibilities of the LV, we aimed through this research to document the superficial venous topographic patterns at the lateral and inferior surfaces of the temporal lobe. (2) Methods: A retrospective cohort of 50 computed tomography angiograms (CTAs) of 32 males and 18 females was documented. (3) Results: Absent (type 0) LVs were found in 6% of cases. Anterior (temporal, squamosal–petrosal–mastoid, type 1) LVs were found in 12% of cases. LVs with a posterior, temporoparietal course (type 2) were found to be bilateral in 46% of cases and unilateral in 36% of cases. Type 3 LVs (posterior, parietooccipital) were found to be bilateral in 8% and unilateral in 32% of cases. In 24% of cases, duplicate LVs were found that were either complete or incomplete. A quadruplicate LV was found in a male case. On 78 sides, the LV drained either into a tentorial sinus or into the TS. (4) Conclusions: The anatomy of the vein of Labbé is variable in terms of its course, the number of veins and the modality of drainage; thus, it should determine personalized neurosurgical and interventional approaches. A new classification of the anatomical variations of Labbé’s vein, as detected on the CTAs, is proposed here (types 0–3).

Small Sphenoid Ridge as a Factor Associated with Laterally Deviated Proximal Sylvian Fissure in Patients Undergoing Pterional Craniotomy

During the pterional-transsylvian approach, we sometimes encounter the proximal Sylvian fissure (SF) deviating laterally beyond the fold of the sphenoidal ridge (SR) and experience difficulty dissecting the SF due to the deep and oblique dissection plane. In the present study, we explored the association between the height of the SR and lateral deviation of the SF during the pterional-transsylvian approach. The association between the height of the SR on axial computed tomography and the presence of a laterally deviated SF was evaluated by reviewing patients who had undergone pterional craniotomy. Among the 52 patients included, lateral deviation of the SF was observed in 8 patients (13.4%). The median height of the SR was significantly smaller in patients with laterally deviated SF (6.0mm) than in patients with non-deviating SF (13.4mm; P<0.0001). The oculomotor nerves and middle fossa were observed at the edge of the dissection plane of the SF in all patients with a laterally deviating SF, while medial structures such as the internal carotid artery or optic nerve were observed in patients with non-deviating SF. Small SR was associated with lateral deviation of the proximal SF.

Socially meaningful visual context either enhances or inhibits vocalisation processing in the macaque brain

Social interactions rely on the interpretation of semantic and emotional information, often from multiple sensory modalities. Nonhuman primates send and receive auditory and visual communicative signals. However, the neural mechanisms underlying the association of visual and auditory information based on their common social meaning are unknown. Using heart rate estimates and functional neuroimaging, we show that in the lateral and superior temporal sulcus of the macaque monkey, neural responses are enhanced in response to species-specific vocalisations paired with a matching visual context, or when vocalisations follow, in time, visual information, but inhibited when vocalisation are incongruent with the visual context. For example, responses to affiliative vocalisations are enhanced when paired with affiliative contexts but inhibited when paired with aggressive or escape contexts. Overall, we propose that the identified neural network represents social meaning irrespective of sensory modality.