Midbrain Cavernous Malformation: Microsurgical Nuances and an Anatomoclinical Review 2-Dimensional Video.

Midbrain cavernous malformations (MCMs) are rare and dangerous taken the important structures and tracts located in this segment of the brainstem. MCM treatment is still controversial, and surgical resection is basically indicated in cases of recurrent hemorrhage and progressive neurologic deterioration. The optimal moment to operate ruptured MCM is in the subacute stage. Once indicated for surgical resection, preoperative planning needs to be individualized. There are various ways to access midbrain lesions, depending on the extension and predominant location: lateral subtemporal, posterior transtentorial, interhemispheric transcallosal, and anterior temporopolar approaches, or some of the alternatives. The aim of this Video 1 case is to review the surrounding anatomic structures and demonstrate the advantages of the semisitting position and the viability of the supracerebellar infratentorial approach for a tegmental midbrain lesion.1-10 In this 2-dimensional video, we present an 18-year-old man with a 4-year history of diplopia and third nerve palsy, which worsened 10 days before admission. He underwent microsurgical total resection of this MCM via extreme lateral supracerebellar infratentorial approach in a semisitting position. At the end, the surgical site and surrounding structures were reviewed microscopically and endoscopically. The patient tolerated the surgery well, and the perioperative course was uneventful. His recovery was smooth but he maintained the previous oculomotor nerve palsy. We discuss important steps of the surgical approach, local neuroanatomy, and the microsurgical techniques for the resection of these challenging MCM. The goal is total resection of the MCM with the preservation of the developmental venous anomaly and the surrounding white fiber tracts.

Left Internal Capsule Cavernoma Using the Superior Frontal Sulcus as a Surgical Corridor: Why and How to Do It: 2-Dimensional Operative Video.

Cavernous angioma is a sinusoidal dilatation covered by a single layer of endothelium, separated by a collagen matrix with elastin and smooth muscle.1 The prevalence in the general population is estimated at 0.4% to 0.9%,2 representing around 5% to 10% of all vascular malformations.3 Studies indicate 9% to 35% of cavernomas are found in deep locations such as the brainstem, thalamus, and basal ganglia.4-6 Common symptoms of these deep lesions are cranial nerve deficit, hemiparesis, and paresthesia. These lesions have high rates of rebleeding after the first episode of bleeding but present excellent results of surgical resection and modified Rankin in the long term.7-13 Internal capsule cavernomas are particularly challenging due to the important projection fibers surround them. Although the gold standard of treatment is microsurgery, there needs to be a consensus on the best approach for lesions of this topography. We present a video case of a female in her 50s with right hemiparesis and dysphasia, exhibiting grade 3/5 strength on the right side. T1 MRI revealed a high intensity, heterogeneous, multinodular signal in the left basal ganglia, with tractography showing the lesion dividing the posterior limb of the internal capsule amid fibers of the right corticospinal tract. The patient consented to the procedure and to the publication of his/her image. This study was approved by the Ethics and Research Committee of our institution. We demonstrated that the superior frontal sulcus is a safe corridor to surgically cure cavernomas of the internal capsule, with the recovery of previous deficits.

Model of Arteriovenous Malformation Created in Human Placenta for Training in Vascular Microneurosurgery.

BACKGROUND AND OBJECTIVE: Arteriovenous malformations (AVMs) are congenital lesions, and because of their structure, complexity, flow, size, and location organization, they are lesions that require extensive anatomic knowledge and mastery of microsurgical skills and techniques. Human placentas as a training model for AVM surgery are promising alternatives. This article aims to describe the technique for forming an AVM-type lesion in human placentas and its usefulness in the training of microsurgical treatment techniques. METHODS: In this study, 15 fresh human placental models were treated. A nidus was created using synthetic material, and dynamic flow was evaluated with intravascular injection of Indocyanine Green. The catheter system was connected to a continuous flow infusion pump. For simulation purposes, 4 vascular neurosurgeons and 4 vascular neurosurgery fellows used the same techniques and instruments used in real surgery to simulate the resection of AVM lesions. Subjective assessments were conducted, evaluating the validity and structured content on a 5-point Likert scale. Evaluation criteria included the execution of technical maneuvers and the model's expression and structural aspects. RESULTS: We describe the step-by-step creation of an AVM in a placental biological model for the performance of vascular microsurgery training in the laboratory. We created in the human placenta a lesion with the characteristics of an AVM for microsurgical training in the laboratory, which presents key features realistic to a real AVM, such as 1 or more feeder arteries, nidus (synthetic), draining vein(s), continuous and pulsatile flow, and 3-dimensional configuration. Furthermore, it demonstrates the applicability of microsurgical techniques to the model compared with performing surgery on a patient. CONCLUSION: Considering it an effective method for laboratory training, the creation of arteriovenous malformations in human placentas enables students to replicate, comprehend the structure, and master microsurgical techniques in a realistic model.

Incidence of venous thromboembolism and bleeding in patients with malignant central nervous system neoplasm: Systematic review and meta-analysis.

Central nervous system (CNS) malignant neoplasms may lead to venous thromboembolism (VTE) and bleeding, which result in rehospitalization, morbidity and mortality. We aimed to assess the incidence of VTE and bleeding in this population. METHODS: This systematic review and meta-analysis (PROSPERO CRD42023423949) were based on a standardized search of PubMed, Virtual Health Library and Cochrane (n = 1653) in July 2023. After duplicate removal, data screening and collection were conducted by independent reviewers. The combined rates and 95% confidence intervals for the incidence of VTE and bleeding were calculated using the random effects model with double arcsine transformation. Subgroup analyses were performed based on sex, age, income, and type of tumor. Heterogeneity was calculated using Cochran's Q test and I2 statistics. Egger's test and funnel graphs were used to assess publication bias. RESULTS: Only 36 studies were included, mainly retrospective cohorts (n = 30, 83.3%) from North America (n = 20). Most studies included were published in high-income countries. The sample size of studies varied between 34 and 21,384 adult patients, mostly based on gliomas (n = 30,045). For overall malignant primary CNS neoplasm, the pooled incidence was 13.68% (95%CI 9.79; 18.79) and 11.60% (95%CI 6.16; 18.41) for VTE and bleeding, respectively. The subgroup with elderly people aged 60 or over had the highest incidence of VTE (32.27% - 95%CI 14.40;53.31). The studies presented few biases, being mostly high quality. Despite some variability among the studies, we observed consistent results by performing sensitivity analysis, which highlight the robustness of our findings. CONCLUSIONS: Our study showed variability in the pooled incidence for both overall events and subgroup analyses. It was highlighted that individuals over 60 years old or diagnosed with GBM had a higher pooled incidence of VTE among those with overall CNS malignancies. It is important to note that the results of this meta-analysis refer mainly to studies carried out in high-income countries. This highlights the need for additional research in Latin America, and low- and middle-income countries.

Microsurgical Resection of a Left Temporal Stem Cavernous Malformation Through Transsylvian Approach: 2-Dimensional Operative Video.

Cavernous malformations (CMs) are rare, often oligosymptomatic vascular lesions. Common manifestations include seizures and focal neurological deficits. Depending on the symptoms, location, size, and risk factors of bleeding, such as the presence of a developmental venous anomaly, the injury can be highly morbid. Hence, one can consider surgical resection. Deep and eloquently located CMs, such as those located in the temporal trunk, can be quite challenging and require an exact operative technique.1-7 We present a 27-year-old patient with a history of headaches that began two years ago and significantly worsened in the last month, associated with visual blurring, scotomas, nausea, phonophobia, and photophobia as well as paresthesias in the hands and perioral region. Imaging investigation revealed a CM in the temporal stem (Zabramski classification II). Owing to the risk of rebleeding and the young age, surgical resection was performed using a transsylvian approach to preserve the temporal cortex. We describe the technique applied and demonstrate the necessary care manipulating the distal sylvian fissure and the superficial sylvian veins. We also detail the anatomy of the temporal stem and the benefit of the transsylvian approach to preserve the white matter fibers that compose the temporal stem. The patient consented to the procedure and to the publication of his/her image. This study was approved by the Ethics Committee of our institution. Performed CM resection using the transsylvian pterional craniotomy technique, and it proceeded without complications. The postoperative period was also uneventful. The postoperative imaging demonstrated total resection of the cavernoma.

Superior frontal sulcus: a non-eloquent corridor for cavernomas of the internal capsule.

Introduction: Deep cavernomas of eloquent areas, located in the region of the basal nuclei and thalamus, account for 9 to 36% of these encephalic vascular malformations. Internal capsule cavernomas are particularly challenging, as they are surrounded by important projection fibers and their manipulation can lead to permanent deficits. To demonstrate through surgical cases that cavernomas of the internal capsule can be approached by frontal craniotomy, via the superior frontal sulcus, in a curative manner and with low morbidity. Methods: We presented two cases of cavernomas of the internal capsule operated, whose treatment was microsurgical resection via frontal craniotomy and access to the lesion via the superior frontal sulcus, described step-by-step. To elucidate the rationale behind the decision, we used preoperative images with an emphasis on the patients' tractography and the importance of comparing these images with anatomical specimens dissected in the neuroanatomy and microsurgery laboratory. Results: The two cases of internal capsule cavernomas, one in the anterior limb and the other in the posterior limb, were treated surgically via the superior frontal sulcus. Discussion: Both patients showed radiological cure and clinical improvement in the post-operative segment. The patient consented to the procedure and to the publication of his/her image. Treatment of internal capsule cavernomas via the superior frontal sulcus has proven to be a safe and effective option.

Neurogenesis and pesticides: news of no new neurons.

New hippocampal neurons are continuously generated in the adult human brain. Several studies have demonstrated that the proliferation of hippocampal cells is strongly influenced by a variety of stimuli, including pesticides exposure. These effects are particularly important because neurogenesis dysregulation could be associated with the decline of neuronal and cognitive functions and the possible development of neuropsychiatric disorders.

Novos neurônios hipocampais são gerados continuamente no cérebro humano adulto. Vários estudos têm demonstrado que a proliferação de células do hipocampo é influenciada por uma variedade de estímulos, incluindo a exposição a pesticidas. Estes efeitos são particularmente importantes porque a desregulação da neurogênese pode estar associada ao declínio das funções neuronais e cognitivas e ao possível desenvolvimento de doenças neuropsiquiátricas.

Enhancing the Microneurosurgical Training: Development of the Folded Placenta Model for Simulation of the Deep Operative Field Challenges of Cranial Procedures.

BACKGROUND AND OBJECTIVE: Neurosurgery relies heavily on advanced manual skills, necessitating effective training models for skill development. While various models have been utilized, the human placenta has emerged as a promising candidate for microneurosurgical training due to its anatomical similarities with cerebral vasculature. However, existing placenta models have primarily focused on simulating superficial procedures, often neglecting the complexities encountered in deep operative fields during cranial surgeries. METHODS: This study obtained ethical approval and implemented a modified placenta model to address the limitations of existing training models. The key modification involved folding the placenta and placing it within a rigid container, closely mimicking the structural challenges of cranial procedures. The placenta preparation followed a standardized protocol, including the use of specialized equipment for documentation. RESULTS: The primary feature of the modified model is the folded placenta within the rigid container, which replicates cranial anatomy. This innovative approach enables trainees to engage in a comprehensive range of microsurgical exercises, encompassing vessel dissection, aneurysm clipping, tumor resection, and more. The model successfully mirrors the complexities of real cranial procedures, providing a realistic training experience. CONCLUSIONS: The presented modified placenta model serves as an effective tool for simulating the conditions encountered in deep cranial surgeries. By accurately replicating the challenges of deep operative fields, the model significantly enhances the training of neurosurgical residents. It successfully prepares trainees to navigate the intricacies and difficulties inherent in real cranial surgeries, thus contributing to improved surgical skills and readiness for neurosurgical practice.

Case report: Association between PTEN-gene variant and an aggressive case of multiple dAVFs.

Introduction: Mutations of the phosphatase and tensin homolog (PTEN) gene have been associated with a spectrum of disorders called PTEN hamartoma tumor syndrome, which predisposes the individual to develop various types of tumors and vascular anomalies. Its phenotypic spectrum includes Cowden syndrome (CS), Bannayan-Riley-Ruvalcaba syndrome (BRRS), Proteus syndrome, autism spectrum disorders (ASD), some sporadic cancers, Lhermitte-Duclos disease (LDD), and various types of associated vascular anomalies. Clinical presentation: A previously healthy 27-year-old woman was experiencing visual scintillating scotomas and mild chronic headaches for the past 2 years. The initial computed tomographic (CT) and magnetic resonance imaging (MRI) scans did not reveal any abnormalities, but the possibility of pseudotumor cerebri was considered. Furthermore, a cerebral angiogram showed a posterior fossa dural arteriovenous fistula (dAVF), which was initially treated through embolization. However, in spite of proper treatment, this patient experienced multiple recurrent dAVFs in different locations, requiring multiple embolizations and surgeries. Despite exhibiting altered cerebral perfusion and hemodynamics, the patient did not display any significant symptoms until she experienced a sudden stroke resulting from deep venous thrombosis, which was not associated with any medical procedures or medication use. A comprehensive analysis was performed due to the aggressive nature of the dAVFs. Surprisingly, exome sequencing of a blood sample revealed a PTEN gene variant in chromosome 10, indicative of Cowden syndrome. However, no tumors or other vascular lesions were detected in other systems that would constitute Cowden syndrome. Conclusion: The rapid formation of multiple and complex dAVFs, coupled with not meeting the criteria for any other PTEN-related syndrome, unequivocally leads to the presentation of a novel phenotype of the PTEN germline variant.

Resection of the quadrangular lobule of the cerebellum to increase exposure of the cerebellomesencephalic fissure: an anatomical study with clinical correlation.

OBJECTIVE: The lateral aspect of the cerebellomesencephalic fissure frequently harbors vascular pathology and is a common surgical corridor used to access the pons tegmentum, as well as the cerebellum and its superior and middle peduncles. The quadrangular lobule of the cerebellum (QLC) represents an obstacle to reach these structures. The authors sought to analyze and compare exposure of the cerebellar interpeduncular region (CIPR) before and after QLC resection and provide a case series to evaluate its clinical applicability. METHODS: Forty-two sides of human brainstems were prepared with Klingler's method and dissected. The exposure area before and after resection of the QLC was measured and statistically studied. A case series of 59 patients who underwent QLC resection for the treatment of CIPR lesions was presented and clinical outcomes were evaluated at 1-year follow-up. RESULTS: The anteroposterior surgical corridor of the CIPR increased by 10.3 mm after resection of the QLC. The mean exposure areas were 42 mm2 before resection of the QLC and 159.6 mm2 after resection. In this series, ataxia, extrapyramidal syndrome, and akinetic mutism were found after surgery. However, all these cases resolved within 1 year of follow-up. Modified Rankin Scale score improved by 1 grade, on average. CONCLUSIONS: QLC resection significantly increased the exposure area, mainly in the anteroposterior axis. This surgical strategy appears to be safe and may help the neurosurgeon when operating on the lateral aspect of the cerebellomesencephalic fissure.

Microsurgical Resection for Cavernous Malformation of the Uncus: 3D-Operative Video.

Cavernous malformations (CMs) are rare and often oligosymptomatic vascular lesions. The main symptoms include seizure and focal neurologic deficits.1-3 Depending on the symptomatology, location, size, and risk factors for bleeding, like the presence of a developmental venous anomaly, CMs can be highly morbid. Thus surgical resection may be considered. Deep-seated and eloquent CMs, like those in the uncus, can be challenging.4,5 In Video 1, we present a 23-year-old male adult who developed focal seizures (i.e., oral automatisms) after an episode of sudden intense headache 1 year ago. His neurologic examination was unremarkable. The patient consented to the procedure and publication of his image. Nevertheless, his magnetic resonance images showed an uncal 2-cm Zabramski type I CM. We exposed the insula and its limen through a right pterional craniotomy and transsylvian corridor. During the video, we discuss the surgical nuances to access and resect this CM lesion en bloc while preserving important vascular structures and white matter tracts. Postoperative neuroimaging demonstrated total resection. In postoperative day 1, the patient had 1 episode of generalized seizure and evolved with contralateral hemiparesis. The patient had a good recovery and was discharged on postoperative day 21. At the 6-month follow-up, the patient had no new epileptic events and presented complete weakness improvement. Through this minimally invasive and well-known surgical corridor, we preserve the mesial and lateral portion of the temporal lobe, reducing the risk of lesions to the Meyer loop and limbic association area.

Case report: Mirror paraclinoid aneurysm associated with mirror clinoidal meningioma.

Introduction: Clinoidal meningiomas and paraclinoid aneurysms are individually uncommon, with the coexistence of mirror paraclinoid aneurysms and clinoidal meningiomas presenting an even rarer scenario. While the association between meningiomas and aneurysms is documented, the simultaneous presence of mirror lesions for both pathologies is not reported in the literature. Clinical presentation: We report a 62-year-old female with a three-month history of moderate bifrontal headaches. Magnetic Resonance Angiography (MRA) revealed mirror paraclinoid aneurysms, prompting surgical intervention. During the procedure, mirror clinoidal meningiomas were incidentally discovered. The left aneurysm was addressed first due to higher rupture risk, followed by the right aneurysm 3 months later. Both meningiomas were confirmed as Transitional Meningiomas (Grade 1; OMS, 2021). The aneurysms were successfully clipped, and the patient had an excellent postoperative outcome. Conclusion: This case represents a unique occurrence of mirror ophthalmic segment internal carotid artery aneurysms associated with mirror clinoidal meningiomas, a combination not previously reported. Despite the limitations of MRA in detecting small meningiomas, it remains a valuable non-invasive screening tool for neurovascular diseases. The case underscores the need for further research to elucidate the association between cerebral aneurysms and meningiomas.

Posterior Transtemporal Approach to a Thalamic Cavernous Malformation: 2-Dimensional Operative Video.

Cavernous malformations (CMs) account for 10%-15% of all vascular malformations and represent the second most common type of cerebral vascular lesion.1 They typically occur in the cerebral subcortex or white matter.2 CMs located in the thalamus are rare.3 When we isolate the group of thalamic CMs, we find a bleeding risk of >5% per year, with a rebleeding rate exceeding 60%, often occurring within 1 year of the initial bleeding.1 The deep location and proximity to eloquent brain regions make thalamic CMs challenging for neurosurgeons.4,5 Surgeons can access the posterolateral thalamus through various surgical approaches, such as transcallosal transventricular, supracerebellar transtentorial, intraparietal sulcus, and transcortical methods. Selecting the best surgical approach requires considerable expertise, considering the patient's preoperative condition and the lesion's location.6-12 We discuss a complex case involving a 24-year-old patient with a right thalamic cavernoma and a history of 3 prior bleeding events. We present a step-by-step transcortical approach through the posterior portion of the superior temporal gyrus (Video 1). The patient consented to the procedure and publication of images. We demonstrate how the transtemporal posterior trajectory provides an optimal working corridor for safely removing this cavernous malformation without introducing new deficits.

Topographical Systematization of Human Placenta Model for Training in Microneurosurgery.

BACKGROUND: Neurosurgical training continuously seeks innovative methods to enhance the acquisition of essential technical skills for neurosurgeons worldwide. While various training models have been employed, few truly replicate real-life conditions optimally. Human placenta is a good model for neurosurgical microsurgery training due to its anatomic similarities to neurovascular structures. Placental vessels exhibit a branching pattern and caliber comparable with intracranial vessels, making them suitable for practicing microsurgical techniques. The study aims to delineate the anatomic zones of the placenta and propose a segmented training model, resulting in a reproducible, cost-effective, and realistic neurosurgical microsurgery training environment. METHODS: Twenty human placentas were meticulously prepared, injected with dyes, and categorized into zones on the basis of anatomic features. Measurements of placental vessels were recorded and compared with cerebral vessels. The placenta was divided into 4 quadrants to facilitate specific training techniques. RESULTS: Our results revealed varying vessel diameters across placental zones, closely resembling cerebral vessels. Different microsurgical techniques were applied to specific placental zones, thereby optimizing training scenarios. The applicability section described exercises such as membrane dissection, vessel skeletonization, aneurysm creation, vascular bypass, and tumor dissection within the placental model, providing detailed guidance on the zones suitable for each exercise. CONCLUSIONS: Human placenta serves as an effective microsurgical training model for neurosurgery, enhancing neurosurgeons' skills through anatomic segmentation. Integrating this model into training programs can significantly contribute to skill acquisition and improved surgical outcomes. Further research is warranted to refine and expand its utilization, complemented by clinical experiences and other simulation tools.

Neurogenesis and pesticides: news of no new neurons / Neurogênese e pesticidas: a ausência de novos neurônios é a novidade

Abstract New hippocampal neurons are continuously generated in the adult human brain. Several studies have demonstrated that the proliferation of hippocampal cells is strongly influenced by a variety of stimuli, including pesticides exposure. These effects are particularly important because neurogenesis dysregulation could be associated with the decline of neuronal and cognitive functions and the possible development of neuropsychiatric disorders.

Resumo Novos neurônios hipocampais são gerados continuamente no cérebro humano adulto. Vários estudos têm demonstrado que a proliferação de células do hipocampo é influenciada por uma variedade de estímulos, incluindo a exposição a pesticidas. Estes efeitos são particularmente importantes porque a desregulação da neurogênese pode estar associada ao declínio das funções neuronais e cognitivas e ao possível desenvolvimento de doenças neuropsiquiátricas.

Decibel Decisions: The Concept of Intracranial Aneurysm Surgery With a Decibel Meter on Two Surgical Cases.

The present cases were used to investigate the reliability of the intraoperative decibel meter as an objective method of clipping efficiency in cerebral aneurysm surgery and to assess the impact of this method on the surgical procedure itself. Different methodologies have been developed and applied to directly or indirectly evaluate the placement of a clip, for example, intraoperative digital subtraction angiography (DSA), intraoperative micro-Doppler ultrasonography, and, more recently, indocyanine green (ICG). We included two patients with a previously non-treated unruptured brain aneurysm. In both patients, intraoperative micro-Doppler was used in combination with a decibel meter app. Here, we present the cases of two patients. In patient one, the pre-clipping average sound level/equivalent continuous sound pressure level (Avg/Leq) was 96.7 dB, while the post-clipping Avg/Leq was 94.4 dB, indicating a reduction in sound level after clipping. Similarly, the pre-clipping time-weighted average noise level (TWA) was 1.2%, while the post-clipping TWA was 0.5%, indicating a decrease in exposure dose after clipping. In patient two, the average sound level for the post-clipping measurement (94.2 dB) was higher than the pre-clipping measurement (93.5 dB), but the difference was not statistically significant. These cases indicate the potential for using sound measurements as a reliable indicator of adequate aneurysm occlusion during clipping procedures. Further research is needed to confirm these findings.