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.

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.

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.

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.

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.

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.

The long-term effect on functional outcome of endoscopic brainwashing for intraventricular hemorrhage compared to external ventricular drainage alone: A retrospective single-center cohort study.

Background: Intraventricular hemorrhage (IVH) is a complex condition with both mechanical and chemical effects, resulting in mortality rates of 50-80%. Recent reports advocate for neuroendoscopic treatment, particularly endoscopic brainwashing (EBW), but long-term functional outcomes remain insufficiently explored. This study aims to outline the step-by-step procedure of EBW as applied in our institution, providing results and comparing them with those of external ventricular drainage (EVD) alone. Methods: We performed a retrospective analysis of adult patients with IVH who underwent EBW and patients submitted to EVD alone at our institution. All medical records were reviewed to describe clinical and radiological characteristics. Results: Although both groups had similar baseline factors, EBW patients exhibited a larger hemoventricle (median Graeb score 25 vs. 23 in EVD, P = 0.03) and a higher prevalence of chronic kidney disease and diabetes. Short-term mortality was lower in EBW (52% and 60% at 1 and 6 months) compared to EVD (80% for both), though not statistically significant (P = 0.06). At one month, 16% of EBW patients achieved a good outcome (Modified Rankin scale < 3) versus none in the EVD group (P = 0.1). In the long term, favorable outcomes were observed in 32% of EBW patients and 11% of EVD patients (P = 0.03), with no significant difference in shunt dependency. Conclusion: Comparing EBW and EVD, patients submitted to the former treatment have the highest modified Graeb scores and, at a long-term follow-up, have better outcomes, demonstrated by the improvement of the patients in the follow-up.

Recurrent Artery of Heubner Guiding the Clip Application for Internal Carotid Artery Bifurcation Aneurysm: 2-Dimensional Operative Video.

Aneurysms of the bifurcation of the internal carotid artery (ICA) represent approximately 5% of intracranial aneurysms and tend to occur in younger patients.1-3 They typically have a superior orientation, in close relationship with the medial (branches of the anterior cerebral artery, segment A1) and lateral (branches of the middle cerebral artery, segment M1) lenticulostriate arteries (LSA), including recurrent artery of Heubner (RAH). RAH commonly originates in the junction of A1 and A2, courses medially to laterally between LSA and anterior cerebral artery, ICA bifurcation, and middle cerebral artery before entering the lateral portion of the anterior perforated substance.4-7 Damage to these arteries are catastrophic. This complex vascular anatomy makes treatment challenging, either endovascular or microsurgical.8-13 We present a video case of microsurgical clipping for the left ICA bifurcation aneurysm. This study was approved by the ethics committee of our institution. The patient, a 46-year-old man, was diagnosed with an unruptured ICA bifurcation aneurysm during workup for intermittent headache. Morphological characteristics of the aneurysm supported intervention over conservative treatment. Digital subtraction angiography showed a prominent proximal RAH crossing between the aneurysm neck and LSA, providing anatomical protection for clip application. Microsurgical clipping was chosen, and the procedure went uneventfully. The patient consented to the procedure and to the publication of his/her image. We discussed and demonstrated throughout the video how we used this anatomic variation and trajectory of the RAH to prevent clipping of LSA unwittingly and achieve complete occlusion of the aneurysm neck.

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.

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.

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.

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.

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.

The Technique for Transorbital Ventricular Puncture: An Anatomic Approach.

BACKGROUND AND OBJECTIVES: Transorbital ventricular puncture is a minimally invasive described procedure with poor landmarks and anatomic references. This approach can be easily performed to save patients with intracranial hypertension, especially when it is secondary to an acute decompensated hydrocephalus. This study aims to describe anatomic structures and landmarks to facilitate the execution of transorbital puncture in emergency cases. METHODS: We analyzed 120 head computed tomographies to show the best area to perform the procedure in the orbital roof. Two adult cadavers (4 sides) were punctured in the predetermined area. Angles, distances, landmarks, and anatomic structures were registered. This approach to the ventricular system may be performed at bedside to relieve intracranial hypertension only in specific cases. RESULTS: The perforation point is 2.5 cm (female) or 3.0 cm (male) lateral to the midline and immediately inferior to the superciliary arch. A vertical line, parallel to midline, was drawn on the outer edge of the patient's forehead, the needle was 45° inferiorly and 20° medially and then progressed 2.0 cm backwards to reach the bone perforation point. After that, it was advanced another 4.5cm approximately until it reached the anterior horn of the lateral ventricle. CONCLUSION: Based on statistical and experimental evidences, we were able to establish reliable anatomic reference points to access the anterior horn of the lateral ventricle through transorbital puncture.