Neuroendoscopic Surgery for Intraventricular Cavernous Malformations: a Review on Indications and Surgical Considerations.

BACKGROUND: Intraventricular cavernous malformations (IVCs) are rare vascular lesions of the central nervous system. Surgical resection remains a challenging endeavor, with conventional microsurgical techniques associated with morbidity due to direct brain tissue manipulation. Neuroendoscopic approaches offer a minimally invasive alternative, though their efficacy and safety in treating IVCs remain underexplored. METHODS: A narrative review was conducted to analyze all documented cases of IVCs treated exclusively with endoscopic transventricular approaches (ETVA). Reviews, original research papers, and case reports published from 1990 to May 2024 were included. When available, surgical videos were also reviewed. RESULTS: Seventeen patients with IVCs primarily located in the foramen of Monro were identified. The mean size of the IVCs was 17 mm (range 7-29 mm). Neuroendoscopic procedures achieved gross total resection in all cases, leading to the resolution of clinical symptoms. Except for one patient who experienced memory impairment post-surgery, no persistent neurological dysfunctions were observed. Intraoperative bleeding, a significant challenge in IVC resection, was managed with continuous warm irrigation and dedicated coagulation instruments. Additionally, 6 cases of neuroendoscopic procedures such as endoscopic third ventriculostomy (ETV) and septum pellucidotomy were reported for managing hydrocephalus (HCP). CONCLUSION: Neuroendoscopic surgery offers several advantages in treating IVCs, including minimally invasive access, precise visualization, and reduced brain tissue manipulation. Our findings support the efficacy and safety of ETVA, underscoring its potential as a valuable therapeutic strategy for selected IVCs.

Stereotactic Radiosurgery for Intracranial Cavernous Malformations: International Stereotactic Radiosurgery Society, Systematic Review, Meta-Analysis, and Practice Guidelines.

OBJECTIVE: The International Stereotactic Radiosurgery Society (ISRS) aims to establish evidence-based guidelines for single-fraction stereotactic radiosurgery (SRS) in treating intracranial cavernous malformations. METHODS: We conducted a systematic review following PRISMA and MOOSE guidelines, searching electronic databases up to January 2024 to assess SRS's impact on post-treatment hemorrhage rates. Pooled risk ratios (RR) and confidence intervals were utilized to quantify this effect, along with assessments of lesion volume changes, seizure outcomes, and SRS-related adverse effects. RESULTS: Our meta-analysis included 32 studies with 2672 patients. A significant decrease in annual hemorrhage rates was observed post-treatment (RR=0.17), with rates of RR=0.29 in the first 2 years and RR=0.11 thereafter. Hemorrhage rates significantly differed before and after 2 years post-SRS (RR=0.36). Among epileptic patients, 20.2% had epilepsy pre-treatment, and 49.9% were seizure-free post-SRS, while 30.6% experienced reduced seizure frequency. Lesion volume changes showed a reduction in 46.9%, stability in 47.1%, and an increase in 6.7%. Symptomatic radiation effects affected 8% of patients. Subgroup analysis revealed symptomatic change rates of 6% at doses ≤13Gy compared to 9% at doses >13Gy. Permanent clinical deficits were rare (2%). CONCLUSION: This meta-analysis suggests SRS is an effective intervention for intracranial cavernous malformations, significantly reducing hemorrhage rates and improving seizure outcomes. ISRS practice guidelines are provided.

Abdominal Pain Mimicking a Neurological Disorder: A Case Report of Spinal Cavernous Malformation in a Pediatric Patient.

We present a case of a 13-year-old boy with abdominal pain initially misdiagnosed as gastrointestinal in origin. Despite initial outpatient management, his symptoms rapidly deteriorated, revealing a central-medullary cavernous malformation causing spinal cord compression. This case underscores the importance of a comprehensive pediatric examination and highlights new treatment approaches for spinal cavernous malformations.

Genetic variants in FCGR2A, PTPN2, VDR as predictive signatures of aggressive phenotypes in cerebral cavernous malformation.

OBJECTIVE: The biological behavior of Cerebral Cavernous Malformation (CCM) is still controversial, lacking a clear-cut signature for a mechanistic explanation of lesion aggressiveness. In this study, we evaluated the predictive capacity of genetic variants concerning the aggressive behavior of CCM and their implications in biological processes. METHODS: We genotyped the variants in VDRrs7975232, VDRrs731236, VDRrs11568820, PTPN2rs72872125 and FCGR2Ars1801274 genes using TaqMan Genotyping Assays in a cohort study with 103 patients, 42 of whom had close follow-up visits for 4 years, focusing on 2 main aspects of the disease: (1) symptomatic events, which included both intracranial bleeding or epilepsy, and (2) the onset of symptoms. The genotypes were correlated with the levels of several cytokines quantified in peripheral blood, measured using the x-MAP method. RESULTS: We report a novel observation that the PTPN2rs72872125 CT and the VDRrs7975232 CC genotype were independently associated with an asymptomatic phenotype. Additionally, PTPN2rs72872125 CC genotype and serum level of GM-CSF could predict a diagnostic association with symptomatic phenotype in CCM patients, while the FCGR2Ars1801274 GG genotype could predict a symptomatic event during follow-up. The study also found a correlation between VDRrs731236 AA and VDRrs11568820 CC genotype to the time to the first symptomatic event. CONCLUSIONS: These genetic markers could pave the way for precision medicine strategies for CCM, enhancing patient outcomes by enabling customized therapeutic approaches.

Minimally invasive tubular approach to intramedullary cavernous malformations.

Background: Advancements in minimally invasive spinal surgery have led to an expansion of targeted pathologies as well as improvements in surgical outcomes compared to their conventional counterparts through open laminectomy; however, this technique is rarely mentioned in the literature for intrinsic cord lesions. The authors present a novel minimally invasive, dorsolateral, and expandable tubular approach for the resection of an intradural, intramedullary thoracic cavernous malformation (CM). Case Descriptions: A 52-year-old male patient presented with rapidly progressive myelopathy and loss of ambulatory capabilities, with which magnetic resonance imaging revealed a hemorrhagic CM within the thoracic spinal cord. The CM was successfully resected through a minimally invasive tubular approach utilizing a dorsal root entry zone myelotomy. Postoperative imaging confirmed gross resection. His motor examination rapidly recovered, and he remains ambulatory with the use of a cane at a 2-year follow-up. Conclusion: This novel minimally invasive approach is a promising technique for well-selected cases of symptomatic spinal CMs. Further exploration and potentially randomized studies are necessary to fully affirm the tubular approach's suitability for the treatment of intradural intramedullary CMs compared to conventional techniques.

The tonsillouvular fissure approach to exophytic cavernous malformation in the lateral recess of the fourth ventricle: 2-dimensional operative video.

Cavernous malformations surrounding the fourth ventricle are challenging lesions to access and treat surgically owing to the complexity and eloquence of adjacent neural tissue [1] Long-standing practice included tissue transgression through the overlying cerebellar cortical surface of the hemisphere or vermis [1-3]. Using natural corridors such as tonsillobiventral fissure, cerebellomedullary fissure, and tonsillouvular fissure (TUF) offers elegant access to the fourth ventricle, avoiding traversing of neural tissue [4-7]. A 32-year-old male presented with headache, nausea, vomiting, double vision, and vertigo. Neuroimaging demonstrated a 17-mm diameter cavernous malformation protruding into the left lateral recess of the fourth ventricle. The patient consented for the procedure and underwent a middline suboccipital craniotomy in a prone position. TUF approach was performed by dissecting the arachnoid to the depth of the fissure, and after identifying the tonsillomedullary segment of the posterior inferior cerebellar artery, minimal white matter transgression was used to reach cavernous malformation. Complete removal of the lesion was achieved and confirmed on postoperative imaging. The postoperative course was uneventful. TUF approach with manipulation by ipsilateral and contralateral retraction of tonsills allows the widening of the surgical corridor and better exposure of lesions of the lateral recess of the fourth ventricle [1]. TUF approach is a valuable alternative to transvermian and transcerebellar approaches that minimize the division of neural tissue [6]. To the best of our knowledge this is the first case describing the TUF approach to exophytic cavernoma presenting in the lateral recess of the fourth ventricle. Under our institutional ethical review board regulations, approval was not necessary.

Comprehensive analysis of Novel mutations in CCM1/KRIT1 and CCM2/MGC4607 and their clinical implications in Cerebral Cavernous malformations.

BACKGROUND: Cerebral Cavernous Malformations (CCM) is a genetic disease characterized by vascular abnormalities in the brain and spinal cord, affecting 0.4-0.5 % of the population. We identified two novel pathogenic mutations, CCM1/KRIT1 c.811delT (p.Trp271GlyfsTer5) and CCM2/MGC4607 c.613_614insGG p.Glu205GlyfsTer31), which disrupt crucial protein domains and potentially alter disease progression. OBJECTIVE: The study aims to comprehensively analyze a Brazilian cohort of CCM patients, integrating genetic, clinical, and structural aspects. Specifically, we sought to identify novel mutations within the CCM complex, and explore their potential impact on disease progression. METHODS: We conducted a detailed examination of neuroradiological and clinical features in both symptomatic and asymptomatic CCM patients, performing genetic analyses through sequencing of the CCM1/KRIT1, CCM2/MGC4607, and CCM3/PDCD10 genes In silico structural predictions were carried out using PolyPhen-2, SIFT, and Human Genomics Community tools. Protein-protein interactions and docking analyses were explored using the STRING database. RESULTS: Genetic analysis identifies 6 pathogenic mutations, 4 likely pathogenic, 1 variants of uncertain significance, and 7 unclassified mutations, including the novel mutations in CCM1 c.811delT and CCM2 c.613_614insGG. In silico structural analysis revealed significant alterations in protein structure, supporting their pathogenicity. Protein-protein interaction analysis indicated nuanced impacts on cellular processes. Clinically, we observed a broad spectrum of symptoms, including seizures and focal neurological deficits. However, no statistically significant differences were found in lesion burden, age of first symptom onset, or sex between the identified CCM1/KRIT1 and CCM2/MGC4607 mutations among all patients studied. CONCLUSION: This study enhances the understanding of CCM by linking clinical variability, genetic mutations, and structural effects. The identification of these novel mutations opens new avenues for research and potential therapeutic strategies.

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.

[Radiosurgery for cerebral cavernous malformations: a systematic review]. / Radiokhirurgicheskoe lechenie kavernoznykh mal'formatsii golovnogo mozga: sistematicheskii obzor literatury.

BACKGROUND: Stereotactic radiosurgery (SRS) for cerebral cavernous malformations has been used for more than 30 years. However, indications for this method and outcomes are still discussable. OBJECTIVE: To analyze available literature data on SRS for cerebral cavernous malformations with assessment of indications for treatment, radiation parameters, radiological and clinical complications and outcomes. RESULTS: The final analysis included 20 reports describing post-SRS outcomes in 1834 patients with cerebral cavernous malformations. The main radiation parameter was mean radiation dose to the edge of cavernous malformation (prescribed dose, 13.25±2.16 Gy). In natural course of malformation, mean incidence of hemorrhages from cavernous malformation when counted after the second hemorrhage was 25.9±14.6%, after the patient's birth - 2.59±0.44%. Mean follow-up period after SRS was 66.7±24.1 months. Incidence of hemorrhages from cavernous malformation after SRS for the first 2 years of follow-up was assessed in 14 studies (4.67±3.51%). Incidence of hemorrhages ≥2 years after SRS was analyzed in 12 studies (1.55±0.8%). CONCLUSION: Despite significant global experience in SRS for cerebral cavernous malformations and many studies devoted to this problem, clear patient selection criteria have not yet been formulated. Modern selection principles have insufficient evidence base.

A Rare Case of Immune Thrombocytopenia With Intracranial Hemorrhage Secondary to Cavernous Malformation.

Immune thrombocytopenia (ITP) is an autoimmune disease resulting in a fall in platelet count, causing ecchymoses and bleeding manifestations. The most prevalent acquired bleeding disorder in children is ITP. Intracranial hemorrhage (ICH) is a rare but most devastating complication of ITP which can cause neurological sequelae. We report the case of a four-year-old male child who presented with a history of seizures, headache, multiple ecchymoses, and bruising. Blood counts and bone marrow examination were suggestive of ITP. Magnetic resonance imaging (MRI) of the brain showed ICH with multiple cerebral cavernous malformations. ICH as the first presentation of ITP is extremely rare. ICH in a case of ITP secondary to arteriovenous malformation has been scarcely reported, establishing the rarity of the currently presented case. Morbidity and mortality of ICH occurring as a consequence of ITP can be reduced by recognizing the symptoms, diagnosing promptly, and treating aggressively.

Waxing and waning consciousness in a patient with a midbrain cavernous malformation: illustrative case.

BACKGROUND: Understanding the intricate relationship between consciousness and the midbrain's structures remains a significant challenge in neuroscience. Transient lesions are perfect examples of the physiological functioning mechanism of these structures. OBSERVATIONS: The authors present the case of a 49-year-old female who experienced a transient disorder of consciousness due to a midbrain hematoma following surgical interventions to remove a cavernous malformation in the midbrain. This case explores the interplay between the ascending reticular activating system (ARAS) and the thalamic centers, highlighting the role of structural disruptions in influencing consciousness levels. Notably, the patient's recovery correlated with the resolution of midbrain edema, reinstating normal ARAS function and consciousness. LESSONS: In patients affected by midbrain lesions, edema can lead to a fluctuating neurological status, which can be difficult to diagnose. This case highlights the midbrain's crucial role in the consciousness network and the need to comprehend the intricate connections between subcortical and cortical structures for a comprehensive understanding of human consciousness. https://thejns.org/doi/10.3171/CASE2411.

Concurrent multiple cerebral cavernous malformations and cauda equina paraganglioma: illustrative case.

BACKGROUND: Cauda equina neuroendocrine tumors (CENETs), previously known as cauda equina paragangliomas, and multiple cerebral cavernous malformations (CCMs) are uncommon conditions affecting the central nervous system. To the authors' knowledge, they have not been reported in the same patient. OBSERVATIONS: The authors present the case of a 45-year-old male with CENET and concurrent incidental MRI findings of multiple CCMs. Familial CCMs are associated with mutations in the KRIT1 (CCM1), MGC4607 (CCM2), and PDCD10 (CCM3) genes. Peripheral paragangliomas have been associated with mutations in succinate dehydrogenase (SDHx), RET (multiple endocrine neoplasia 2), VHL (von Hippel-Lindau syndrome), and NF1 (neurofibromatosis type 1) genes. Except for a single case, cauda equina paragangliomas have not been associated with any underlying genetic mutations. LESSONS: It is unclear whether the co-occurrence of these two rare conditions in the same patient is coincidental or suggests a possible shared pathogenesis. https://thejns.org/doi/10.3171/CASE24102.

Multiple Cavernous Malformation Syndrome in an Infant: A Case Report.

Cerebral cavernomas belong to a group of vascular lesions characterized by varying structural properties and presentations. Clinical manifestations vary among patients and are particularly influenced by age, posing challenges in diagnosis and treatment. Here, we present a pediatric case of a cerebral cavernoma, which is very rare. We further aim to emphasize the importance of a good physical examination.

Complete removal of a cavernous malformation in the dorsal pons, in contact with the expanded transpontine vein: illustrative case.

BACKGROUND: Craniotomy is required for the removal of brainstem cavernous malformations (CMs) with repeated hemorrhage, and this condition is often complicated by an accompanying developmental venous anomaly (DVA). However, a DVA of the brainstem or cerebellum with drainage penetrating the pons is an exceptional finding. OBSERVATIONS: A 57-year-old man presented with double vision. Computed tomography revealed progressive enlargement of the hemorrhage in the dorsal pons. Contrast-enhanced magnetic resonance angiography revealed an expanded transverse vessel penetrating the center of the pons in contact with the CM. Digital subtraction angiography revealed that the DVA, comprising the expanded transpontine vein and some cerebellar medullary veins acting as normal venous drainage, coexisted with the CM. By utilizing the angioarchitecture and intraoperative neuronavigation system data, electrophysiological mapping, and indocyanine green videoangiography, complete removal of the CM was accomplished while preserving the DVA and brain function. LESSONS: This study presents the intraoperative images of an expanded transpontine vein as a DVA, which has never been depicted in a live patient before, accompanied by a CM in the dorsal portion of the pons. https://thejns.org/doi/10.3171/CASE24314.

Long-Term Outcomes of Gamma Knife Radiosurgery for Cerebral Cavernous Malformations: 10 Years and Beyond.

BACKGROUND: We aimed to evaluate long-term outcomes of gamma knife radiosurgery (GKS) for cerebral cavernous malformations (CCMs). METHODS: Among the 233 CCM patients who underwent GKS, 79 adult patients (96 lesions) followed for over 10 years were included and analyzed retrospectively. Annual hemorrhage rate (AHR) was analyzed the entire cohort of 233 patients and the subset of 79 enrolled patients by dividing lesions into overall CCM lesions and brainstem lesions. AHR, neurologic outcome, adverse radiation effect (ARE), and changes of lesions in magnetic resonance imaging (MRI) were compared before and after GKS. Cox-regression analysis was performed to identify risk factors for hemorrhage following GKS. RESULTS: Mean follow-up duration of 79 enrolled patients was 14 years (range, 10-23 years). The AHR of all CCMs for entire cohort at each time point was 17.8% (pre-GKS), 5.9% (≤ 2 years post-GKS), 1.8% (≤ 10 years post-GKS). The AHR of all CCM for 79 enrolled patients was 21.4% (pre-GKS), 3.8% (2 years post-GKS), 1.4% (10 years post-GKS), and 2.3% (> 10 years post-GKS). The AHR of brainstem cavernous malformation (CM) for entire cohort at each time point was 22.4% (pre-GKS), 10.1% (≤ 2 years post-GKS), 3.2% (≤ 10 years post-GKS). The AHR of brainstem CM for 79 enrolled patients was 27.2% (pre-GKS), 5.8% (2 years post-GKS), 3.4% (10 years post-GKS), and 3.5% (> 10 years post-GKS). Out of the 79 enrolled patients, 35 presented with focal neurologic deficits at the initial clinical visit. Among these patients, 74.3% showed recovery at the last follow-up. Symptomatic ARE occurred in five (6.4%) patients. No mortality occurred. Most lesions were decreased in size at the last follow-up MRI. Previous hemorrhage history (hazard ratio [HR], 8.38; 95% confidence interval [CI], 1.07-65.88; P = 0.043), and brainstem location (HR, 3.10; 95% CI, 1.26-7.64; P = 0.014) were significant risk factors for hemorrhage event. CONCLUSION: GKS for CCM showed favorable long-term outcomes. GKS should be considered for CCM, especially when it has a previous hemorrhage history and brainstem location.

Sublabial transmaxillary approach to the inferior aspect of the orbit.

OBJECTIVE: The objective was to demonstrate the surgical steps and outcomes of the sublabial transmaxillary microsurgical approach with endoscopic assistance to treat lesions in the inferior aspect of the orbit, as well as to describe the use of patient-specific 3D models to facilitate surgical preparation and improve experience with the technique. METHODS: The authors' study evaluated data from patients who underwent an endoscope-assisted sublabial transmaxillary approach for inferior orbital lesions. For 2 patients, 3D models were created for preoperative planning and assessment of the approach. Surgical steps comprised osteotomy to access the maxillary sinus, bony resection of the orbital floor, opening of the periorbital fascia, and dissecting and removing the lesion, followed by closure. The neuroendoscope was used to inspect the surgical cavity between each step. RESULTS: The study included 5 patients with varying visual field defects and proptosis who underwent the sublabial transmaxillary microsurgical approach with endoscopic assistance. Complete resection was achieved in all, and all patients reported improvement in visual field defects and proptosis after the procedure. No complications were observed except for transient unilateral maxillary edema noted around the incision site in 3 patients during the early postoperative period, which resolved within a few days. Histopathological examination confirmed the diagnosis of cavernous malformation in all patients. CONCLUSIONS: The sublabial transmaxillary approach is a direct and safe method to resect cavernous malformations at the inferior aspect of the orbit. It reduces the risk of complications associated with lateral, transcranial, and transnasal approaches that may cross critical structures. The microsurgical approach provides the benefit of two-handed dissection for lesions embedded in orbital fat, which can be challenging because of adhesions to surrounding tissues. The use of 3D models can facilitate surgical planning and enhance familiarity with the approach.

Tobacco use increases lesion burden in familial cerebral cavernous malformation syndrome.

BACKGROUND: Familial cerebral cavernous malformation (CCM) syndrome is characterized by multiple, non-contiguous cavernous malformations. The lesion burden may affect morbidity. Our aim was to identify risk factors for high lesion burden in these patients. METHODS: Patients with radiologically confirmed CCM were screened between 2015 and 2023. Only familial or presumed familial CCM patients were included. Demographic information and medical history at the time of diagnosis were evaluated. The first diagnostic MRI was used to determine T2 total and T2 large lesion (≥5 mm) count. Chi-square was used to determine risk factors for total T2 large lesion count ≥5. RESULTS: Of 107 patients with familial or presumed familial CCM (55.1 % female, age 42.4 years), the median total T2 lesion count and large lesion count was 4 (range: 1-109) and 2 (range: 0-50) respectively. Current tobacco use was a risk factor for T2 large lesion count ≥5. CONCLUSION: Further studies combining familial cohorts and assessing length of exposure may be useful to confirm tobacco as a risk factor for T2 large lesion formation in familial CCM.

Except for Robust Outliers, Rapamycin Increases Lesion Burden in a Murine Model of Cerebral Cavernous Malformations.

Cerebral cavernous malformation (CCM) is a hemorrhagic cerebrovascular disease where lesions develop in the setting of endothelial mutations of CCM genes, with many cases also harboring somatic PIK3CA gain of function (GOF) mutations. Rapamycin, an mTORC1 inhibitor, inhibited progression of murine CCM lesions driven by Ccm gene loss and Pik3ca GOF, but it remains unknown if rapamycin is beneficial in the absence of induction of Pik3ca GOF. We investigated the effect of rapamycin at three clinically relevant doses on lesion development in the Ccm3-/-PDGFb-icreERPositive murine model of familial CCM disease, without induction of Pik3ca GOF. Lesion burden, attrition, and acute and chronic hemorrhaging were compared between placebo and rapamycin-treated mice. Plasma miRNome was compared to identify potential biomarkers of rapamycin response. Outlier, exceptionally large CCM lesions (> 2 SD above the mean lesion burden) were exclusively observed in the placebo group. Rapamycin, across all dosages, may have prevented the emergence of large outlier lesions. Yet rapamycin also appeared to exacerbate mean lesion burden of surviving mice when outliers were excluded, increased attrition, and did not alter hemorrhage. miR-30c-2-3p, decreased in rapamycin-treated mouse plasma, has gene targets in PI3K/AKT and mTOR signaling. Progression of outlier lesions in a familial CCM model may have been halted by rapamycin treatment, at the potential expense of increased mean lesion burden and increased attrition. If confirmed, this can have implications for potential rapamycin treatment of familial CCM disease, where lesion development may not be driven by PIK3CA GOF. Further studies are necessary to determine specific pathways that mediate potential beneficial and detrimental effects of rapamycin treatment, and whether somatic PIK3CA mutations drive particularly aggressive lesions.

Transcallosal Retroforniceal Transchoroidal Approach: To the Posterior Third Ventricle and Beyond.

BACKGROUND: The transcallosal retroforniceal transchoroidal approach represents an advanced neurosurgical technique that allows access to lesions located within the posterior third ventricle and mesencephalon. It relies on a comprehensive understanding of microsurgical anatomy and embryology, integrating modern neurosurgical operative techniques to minimize retraction and injury to the normal neuronal structures. METHODS: We report the cases of 2 patients undergoing treatment via this approach, one presenting with a thalamic cavernoma and the other with cystic low-grade glioma of the midbrain. RESULTS: In these 2 cases, the decision to use the transcallosal approach was mainly due to improved trajectory, gravitational retraction of the hemisphere, and improved delivery of the lesion into the operative field by gravity alone. CONCLUSIONS: Through a detailed description of the surgical approach and anatomy, we illustrate the feasibility of the transcallosal retroforniceal transchoroidal approach for accessing lesions located deeply in the brain.

Minipterional craniotomy for resection of epileptogenic cavernous malformation.

Epilepsy is a common symptom of pediatric cavernous malformations. In medically refractory patients, surgery can achieve high seizure freedom rates with low morbidity. This video depicts the use of a minipterional craniotomy and transsulcal resection of a frontal opercular cavernous malformation in a 13-year-old female with medically intractable epilepsy. At 1-year follow-up, she was evaluated as Engel class I with a significant improvement in her quality of life. Principles of cavernous malformation resection for the treatment of epilepsy are also reviewed. The video can be found here: https://stream.cadmore.media/r10.3171/2024.4.FOCVID2441.