Volumetric measurement of intracranial meningiomas: a comparison between linear, planimetric, and machine learning with multiparametric voxel-based morphometry methods.

PURPOSE: To compare the accuracy of three volumetric methods in the radiological assessment of meningiomas: linear (ABC/2), planimetric, and multiparametric machine learning-based semiautomated voxel-based morphometry (VBM), and to investigate the relevance of tumor shape in volumetric error. METHODS: Retrospective imaging database analysis at the authors' institutions. We included patients with a confirmed diagnosis of meningioma and preoperative cranial magnetic resonance imaging eligible for volumetric analyses. After tumor segmentation, images underwent automated computation of shape properties such as sphericity, roundness, flatness, and elongation. RESULTS: Sixty-nine patients (85 tumors) were included. Tumor volumes were significantly different using linear (13.82 cm3 [range 0.13-163.74 cm3]), planimetric (11.66 cm3 [range 0.17-196.2 cm3]) and VBM methods (10.24 cm3 [range 0.17-190.32 cm3]) (p < 0.001). Median volume and percentage errors between the planimetric and linear methods and the VBM method were 1.08 cm3 and 11.61%, and 0.23 cm3 and 5.5%, respectively. Planimetry and linear methods overestimated the actual volume in 79% and 63% of the patients, respectively. Correlation studies showed excellent reliability and volumetric agreement between manual- and computer-based methods. Larger and flatter tumors had greater accuracy on planimetry, whereas less rounded tumors contributed negatively to the accuracy of the linear method. CONCLUSION: Semiautomated VBM volumetry for meningiomas is not influenced by tumor shape properties, whereas planimetry and linear methods tend to overestimate tumor volume. Furthermore, it is necessary to consider tumor roundness prior to linear measurement so as to choose the most appropriate method for each patient on an individual basis.

Use of diffusion tensor imaging as a prognostic biomarker after decompression surgery for carpal tunnel syndrome.

BACKGROUND: Magnetic resonance diffusion tensor imaging (MR-DTI) has been increasingly applied for carpal tunnel syndrome (CTS) diagnosis, but relatively little is known about the effect of CTS treatment on median nerve (MN) integrity and functional outcome prediction. PURPOSE: To assess how structural changes in MR-DTI of the MN correlates with symptom severity, functional status, and electrophysiological parameters in patients suffering from CTS before and after decompression surgery. MATERIAL AND METHODS: Nine wrists were prospectively enrolled to perform MR-DTI pre- and postoperatively. The apparent diffusion coefficients (ADC) and fractional anisotropy (FA) of the MN were examined in three different regions-distal radioulnar joint, pisiform bone, and hamate bone-and correlated with clinical and electrophysiological parameters. RESULTS: Postoperatively, mean Boston Carpal Tunnel Questionnaire scores decreased 1.55 points (range = 0.08-3; P = 0.0172) and 1.01 points (-0.13 to 1.88; P = 0.0381) in the symptomatic and functional domains, respectively. Postoperative clinical improvement was reflected in proximal FA elevation (P = 0.0078), but not in diffusivity in comparison to baseline examination. Preoperative electrophysiological parameters were correlated with a reduction in the pre- (sensory latencies [rho = -0.6826; P = 0.0312]) and postoperative (motor latencies [rho = -0.7488; P = 0.0325]) distal FA values. Higher sensory amplitudes indicated higher postoperative proximal FA values (rho = 0.7618; P = 0.0280) ​​and lower postoperative proximal ADC values (rho = -0.9047; P = 0.0020). CONCLUSION: Our study demonstrated that pre- and postoperative proximal FA values are useful biomarkers for the structural evaluation of the MN in patients with CTS. Symptomatic improvement can be better predicted by analyzing FA changes.

"Million dollar nerve" magnetic resonance neurography: first normal and pathological findings.

OBJECTIVES: To evaluate prospectively the feasibility of magnetic resonance neurography (MRN) in identifying the anatomical characteristics of thenar muscular branch (TMB) of the median nerve, also known as the "million dollar nerve," in patients and controls. METHODS: Thirteen patients affected by carpal tunnel syndrome (CTS) and four healthy controls had their hands scanned on a 3-T MR imaging scanner for TMB visualization. Median nerve anatomical variations were classified into four groups according to Poisel's classification system modified by Lanz. TMB signal intensity and diameter were assessed for the diagnosis of neuropathy. RESULTS: TMB was successfully identified in all patients and subjects by using MRN. The most suitable pulse sequences to identify and measure nerve diameter were 3D DW-PSIF and T2-FS-TSE. The axial oblique and sagittal oblique planes are complementary in demonstrating its entire course. TMB had mostly an extraligamentous course with radial side origin (93.8%, each). All patients experienced increased T2 signal intensity (p < 0.001) and thickened nerves. Mean TMB diameters were 1.27 ± 0.21 mm (range, 1.02-1.74 mm) and 0.87 ± 0.16 mm (0.73-1.08 mm) (p = 0.008) in the patient and control groups, respectively. CONCLUSION: MRN is a reliable imaging technique for identification and anatomical characterization of TMB in patients affected by CTS. This innovative imaging workup may therefore be included in the preoperative evaluation of patients scheduled for carpal tunnel release, especially in CTS with TMB involvement or even in isolated TMB neuropathy. KEY POINTS: • Magnetic resonance neurography allows precise visualization of the thenar muscular branch of the median nerve. • Thenar muscular branch anatomical variations can be correctly identified. • Preoperative scanning can contribute to reducing the risk of iatrogenic injuries during carpal tunnel release, especially in carpal tunnel syndrome with thenar muscular branch involvement or even in isolated thenar muscular branch neuropathy.

Universal fluorescence module for intraoperative fluorescein angiography-a technical report.

BACKGROUND: Even in specialized centers, suboptimal aneurysm clipping can be as high as 12%. Intraoperative fluorescence angiography with indocyanine green and, more recently, fluorescein sodium have been shown to be a good method for intraoperative flow assessment. However, the cost with the apparatus it entails limits its widespread use. We have developed a low-cost universal fluorescence module (FM) designed to visualize fluorescein and perform intraoperative angiography. The purpose of this paper is to describe this device as well as to present our early experience with its use in the treatment of cerebral aneurysms. METHOD: A FM was designed and built using a cyan-blue narrow bandpass (460 to 490 nm) excitation filter and a yellow-orange longpass (blocking wavelengths under 520 nm) barrier filter mounted on a 3D-printed holding tray in a specific disposition to perfectly match the light source and the objective lens of the surgical microscope. It allowed switching from white light to fluorescence mode in a simple and sterile fashion. Its perfect attachment to the microscope was possible by reusing the lens fittings extracted from used original drape sets that would otherwise be discarded. Four patients underwent aneurysm clipping using the FM at two institutions from April to September 2018. RESULTS: A bright green fluorescence against a dark background was observed after intravenous bolus of fluorescein. Blood vessels became obviously distinct from non-contrast-filled structures such as clipped aneurysms and the brain. Vascular anatomy could be appreciated without any distortion, including perforating arteries. CONCLUSIONS: Intraoperative fluorescence angiography was successfully performed with the use of this universal FM after intravenous injection of fluorescein sodium. This simple and low-cost device may be useful in resource-limited centers, where other sorts of intraoperative angiography are not available.

Patients' perspective on awake craniotomy for brain tumors-single center experience in Brazil.

BACKGROUND: Awake craniotomy with brain mapping is the gold standard for eloquent tissue localization. Patients' tolerability and satisfaction have been shown to be high; however, it is a matter of debate whether these findings could be generalized, since patients across the globe have their own cultural backgrounds and may perceive and accept this procedure differently. METHODS: We conducted a prospective qualitative study about the perception and tolerability of awake craniotomy in a population of consecutive brain tumor patients in Brazil between January 2013 and April 2015. Seventeen patients were interviewed using a semi-structured model with open-ended questions. RESULTS: Patients' thoughts were grouped into five categories: (1) overall perception: no patient considered awake craniotomy a bad experience, and most understood the rationale behind it. They were positively surprised with the surgery; (2) memory: varied from nothing to the entire surgery; (3) negative sensations: in general, it was painless and comfortable. Remarks concerning discomfort on the operating table were made; (4) postoperative recovery: perception of the postoperative period was positive; (5) previous surgical experiences versus awake craniotomy: patients often preferred awake surgery over other surgery under general anesthesia, including craniotomies. CONCLUSIONS: Awake craniotomy for brain tumors was well tolerated and yielded high levels of satisfaction in a population of patients in Brazil. This technique should not be avoided under the pretext of compromising patients' well-being.

Morphometric analysis of the medial opticocarotid recess and its anatomical relations relevant to the transsphenoidal endoscopic endonasal approaches.

BACKGROUND: The medial opticocarotid recess (MOCR) is located in the posterior wall of the sphenoid sinus, medial to the junction of the optic canal (OC) and the carotid prominence (CP). There is controversy in the literature in relation to the presence of the MOCR and its constancy, which is relevant when approaching the skull base through an endoscopic route. METHODS: The morphometric relations of the MOCR with the surrounding structures were studied in 18 cadaveric specimens after endoscopic endonasal approach (EEA). RESULTS: The distance between both MOCR was 11.06 ± 1.14 mm; the distance between the MOCR and the lateral opticocarotid (LOCR) recess was 5.56 ± 0.85 mm; the distance between the MOCR and the suprasellar recess was 3.72 ± 0.49 mm; the angle between the MOCR plane and the OC 13.32 ± 2.30°; the angle between the MOCR plane and the CP 13.50 ± 2.68° and; the angle between the OC and the CP 26.81 ± 4.26°. All measurements showed low variability, with low standard deviation and interquartile range. No relations were found between any of the measurements. CONCLUSIONS: The MOCR may be used as a reference point for precise location of structures during EEA. Objective measurements may be especially useful in cases with distorted sphenoid bone anatomy.

A prospective study on the usefulness of high-resolution intraoperative infrared thermography in intracranial tumors.

Introduction: Infrared thermography (IT) is a non-invasive real-time imaging technique with potential application in different areas of neurosurgery. Despite technological advances in the field, intraoperative IT (IIT) has been an underestimated tool with scarce reports on its usefulness during intracranial tumor resection. We aimed to evaluate the usefulness of high-resolution IIT with static and dynamic thermographic maps for transdural lesion localization, and diagnosis, to assess the extent of resection, and the occurrence of perioperative acute ischemia. Methods: In a prospective study, 15 patients affected by intracranial tumors (six gliomas, four meningiomas, and five brain metastases) were examined with a high-resolution thermographic camera after craniotomy, after dural opening, and at the end of tumor resection. Results: Tumors were transdurally located with 93.3% sensitivity and 100% specificity (p < 0.00001), as well as cortical arteries and veins. Gliomas were consistently hypothermic, while metastases and meningiomas exhibited highly variable thermographic maps on static (p = 0.055) and dynamic (p = 0.015) imaging. Residual tumors revealed non-specific static but characteristic dynamic thermographic maps. Ischemic injuries were significantly hypothermic (p < 0.001). Conclusions: High-resolution IIT is a non-invasive alternative intraoperative imaging method for lesion localization, diagnosis, assessing the extent of tumor resection, and identifying acute ischemia changes with static and dynamic thermographic maps.

Large Vestibular Schwannoma: A Two-Stage Surgery.

Treatment of large vestibular schwannoma (VS) has historically centered on total resection of the lesion. Staged surgery has been used for VS that is highly vascularized, unexpected events during surgery, and thinned and stretched facial nerve with serious adherence causing difficult dissection. We present a case of a patient with a large VS resected through a two-stage surgery through the same retrosigmoid craniotomy.

Surgical salvage for recurrent vestibular schwannoma after primary stereotactic radiosurgery.

Background: The management of vestibular schwannoma has evolved over the past hundred years. In the last decades, surgery has been gradually replaced by radiation therapy as a primary treatment modality, particularly for small tumors, due to the less invasive nature and the compared reported outcomes in tumor control and hearing preservation. However, irradiation sometimes fails to stop tumor growth. In a long-term follow-up after primary fractionated stereotactic radiotherapy, the rate of treatment failure was reported as 3% and needed surgical salvage. For single-fraction modality, Hasegawa et al. reported salvage treatment after primary Gamma Knife radiosurgery in 8%, where 90% of these underwent surgery and 50% of those who were treated with a second gamma knife surgery required surgical intervention later. An increase in tumor volume by more than 10-20%, tumor growth after three years, and no return to pretreatment volume after transient swelling have been considered as tumor recurrence rather than pseudoprogression, a transient increase in tumor volume after radiotherapy that occurs up to 30% of cases. It has been reported that microsurgery after radiotherapy is more difficult, with most authors reporting a loss of defined arachnoid planes and worse cranial nerve outcomes, especially for hearing and facial nerve function. Case Description: A 43-year-old female patient was incidentally (asymptomatic) diagnosed on a magnetic resonance imaging (MRI) scan harboring a left vestibular schwannoma, grade T2 (Hannover classification), in 2015. Neurologic examination was unremarkable, and audiometry testing was normal. She was initially treated with observation. Three years later, in 2018, the lesion had enlarged, becoming a grade T3a and reaching the cistern of the cerebellopontine angle. The tumor was then treated with fractionated stereotactic radiosurgery (5 sessions of 5 Gy). MRI scans in 2019 and 2020 showed slight tumor growth. This enlargement was attributed to a pseudoprogression after radiosurgery, and only observation was advocated. In 2022, 4 years later, after radiosurgery, the tumor was still growing, and the patient began to suffer from hearing loss. A failure treatment was considered, and microsurgery was indicated. The patient was counseled about the risk of functional nerve impairment, and surgical consent was obtained. A retro sigmoid approach was planned. A gross total resection was attempted due to the clear subperineural plane during tumor dissection and because it was the only option that would provide a cure for the patient. The adjacent neurovascular structures were firmly adhered to the tumor capsule, which represented a major challenge for microdissection. The tumor was soft, without significant bleeding. A total resection was achieved, and the facial nerve was anatomically preserved. The patient developed facial paresis (House-Brackmann III) in the immediate postoperative period, which improved at the 6-month follow-up. Hearing loss did not improve. Postoperative MRI showed total resection. Conclusion: Microsurgery after radiotherapy for vestibular schwannoma is challenging in terms of indication, when to indicate, resection target, difficulty in dissection due to local changes, and outcome. Gross total resection may be considered, as it is the only treatment that may provide a cure for the patient. However, the patient should be counseled about the risks.

Foramen magnum meningioma approached by the midline subtonsilar approach - Revisiting Cushing's classification of craniospinal meningiomas.

Background: The management of foramen magnum meningiomas (FMMs) has been a challenge for skull base neurosurgeons. Since the initial description of a FMM in 1872, various surgical approaches have been described. Posterior and posterolateral FMMs are safely removed through a standard midline suboccipital approach. Nevertheless, we still face controversy regarding the management of anterior or anterolateral lesions. Case Description: A 47-year-old patient presented with progressive headaches, unsteadiness, and tremor. Magnetic resonance imaging showed an FMM that caused significant displacement of the brainstem. Conclusion: This operative video highlights a safe and effective surgical technique for the resection of an anterior foramen magnum meningioma.

Safety of withholding perioperative steroids for patients with pituitary resection with an intact hypothalamus-pituitary-adrenal axis: A meta-analysis of randomized clinical trials.

INTRODUCTION: Several observational studies have evaluated the effects of pre-operative steroids (STER) for transsphenoidal pituitary removal in patients with an intact hypothalamus-pituitary-adrenal axis. However, a consensus built upon randomized studies has not been previously performed. PURPOSE: To comprehensively evaluate the clinical effects of patients receiving STER when compared to those not receiving steroids (NOSTER) in transsphenoidal pituitary resection, a meta-analysis of randomized clinical trials (RCT) was conducted. METHODS: A systematic review of the literature of RCTs comparing STER and NOSTER was performed in accordance with the PRISMA guidelines. Databases, including PUBMED, Cochrane Library, Web of Science, and Embase were queried. The primary outcomes were adrenal insufficiency (AI) and diabetes insipidus (DI) post-operatively. RESULTS: A total of 4 final studies were included, in which 530 total patients were analyzed. The meta-analysis suggested that there was no significant difference between STER and NOSTER groups post-operatively related to transient AI (RR= 0.83, 95% CI [0.51-1.35], p = 0.45; I² = 52%), permanent AI (RR= 0.97, 95% CI [0.41-2.31], p = 0.95; I² = 0%), and permanent DI (RR= 0.62, 95% CI [0.16-2.33], p = 0.48; I² = 0%). Nevertheless, STER group had significantly lower rates of transient DI (RR= 0.60, 95% CI [0.38-0.95], p = 0.03; I² = 5%), and post-op hyponatremia (RR = 0.49, 95% CI [0.28-0.87], p = 0.02; I² = 0%). CONCLUSION: This study demonstrates evidence from RCTs that patients receiving pre-operative STER are both safe and effective pre-operatively for resection of pituitary adenomas with an intact hypothalamus-pituitary-adrenal axis.

Cavernous sinus medial wall: dural or fibrous layer? Systematic review of the literature.

The cavernous sinus (CS) has one of the most complex anatomical networks of the skull base and because of the diversity of its contents is involved in many pathological processes. Nevertheless, anatomical literature concerning the CS is still controversial, so a systematic literature review was performed to find out the microanatomy of the medial wall of the CS and its clinical importance on sellar pathologies. Experimental studies from English-language literature between 1996 and 2010 were identified in MEDLINE, LILACS, and Cochrane databases. After analysis, two tables were prepared exhibiting the major points of each article. Fourteen experimental studies were included in the tables. Four studies concluded that the medial wall of the CS is composed of a loose, fibrous structure, and the remaining ten presumed that the medial wall is formed by a dural layer that constitutes the lateral wall of the sella. The lack of definition standards and of methodological criteria led to variation in the results among different studies. Thus, this hindered results comparison, possibly explaining the different observations.

Anterior petrosal approach for petroclival solitary plasmacytoma.

Background: Primary solitary plasmacytoma (PSP) of the skull base is a rare localized monoclonal plasma cell dyscrasia with normal or low plasma cell infiltration. Differentiating from other skull base tumors based on radiologic findings is difficult due to nonspecific features. PSP has a better prognosis after surgical resection and adjuvant radiotherapy, unless the tumor progresses to multiple myeloma (MM). Nonetheless, 50-60% progress to MM within a median time of 2 years. Gross total resection (GTR) for PSP is controversial for improving overall survival. However, if the lesion is easily accessible, for example, nonskull base lesion, GTR is still advocated. Case Description: A 67-year-old male patient presented with right occipital neuralgia and diplopia in the last year. Neurological examination revealed mild abducens paresis on the right side. Brain MRI scan showed a large petroclival bony extradural mass lesion on the right side, with homogeneous enhancement, extending from the dorsum sellae to the ipsilateral occipital condyle and involving the petrous carotid artery. Brain CT scan revealed an osteolytic lesion without intratumoral calcifications, sclerotic border, or periosteal reaction. Anterior petrosal approach was performed and GTR was achieved. The patient had good postoperative outcome and improvement of symptoms. Postoperative MRI revealed GTR. Total body imaging work-up and immunohistochemistry confirmed PSP. Conclusion: Although the extent of resection in the outcome is controversial, maximal safe resection of skull base PSP should be considered to improve symptoms and quality of life.

A Giant Internal Carotid Bifurcation Aneurysm as a Rare and Dangerous Differential Diagnosis of a Craniopharyngioma.

Craniopharyngiomas are supra/parasellar lesions that often present with general, unspecific symptoms. Similarly, internal carotid artery (ICA) bifurcation giant aneurysms may also produce calcified, heterogeneous, parasellar expansive lesions, posing a relevant differential diagnosis due to their inherently different surgical strategies and risks. We report the case of a 54-year-old female presenting with progressive disorientation and apathetic behavior. CT and MRI reports described a suprasellar heterogenous mass with calcifications associated with an adjacent, laterally located fluid collection suggestive of a craniopharyngioma. During the surgical procedure, perfuse and unexplained arterial bleeding ensued, prompting the surgical team to review a previous contrast-enhanced CT scan. Careful inspection revealed an image suggestive of vascular pathology, with an area of continuous hyperdensity along the right ICA bifurcation. The Sylvian fissure was dissected, and an aneurysmal neck was encountered and successfully clipped. Giant intracranial aneurysms are rare but essential differential diagnoses to be considered during the workup and surgical approach toward parasellar mass lesions. This case illustrates the importance of performing a CT angiogram (CTA) for skull base lesions, even when the size is more suggestive of tumor pathology.

Orbitozygomatic approach for large orbital cavernous hemangioma.

BACKGROUND: Cavernous hemangiomas, more accurately defined as cavernous venous malformations, constitute the most common primary intraorbital tumors of adults comprising 4-9% of all tumors,[4] and the second most frequent cause of unilateral proptosis after thyroid-related orbitopathy.[3] Over 80% are located within the intraconal compartment, most commonly in the lateral aspect.[1] Surgical treatment for orbital cavernous hemangioma is generally required in symptomatic cases, optic nerve compression, and cosmetically disfiguring proptosis.[2] Transcranial approaches, the most familiar approaches for neurosurgeons, provide wide access to the entire superior and lateral orbit. They usually offer direct visualization, allowing for a safer dissection, while minimizing significant injury to the native neural and vascular anatomy of the orbit.[5] Although transcranial approaches continue to evolve, in many cases, they have been supplanted by endoscopic skull base approaches and modifications to deep lateral orbitotomy approaches.[5]. CASE DESCRIPTION: A 62-year-old male patient presented with slowly expanding left proptosis, which he had first noticed 3 years before presentation. He was already blind in his right eye due to a history of traumatic amaurosis in childhood. The left eye examination revealed severe proptosis with restricted eye movement in all directions and significant visual impairment (visual acuity of 20/300, expressed by Snellen test, with no improvement on correction). MRI of the orbit showed a large left superolateral intraconal cavernous hemangioma compressing and displacing the optic nerve, with the typical feature of slow gradual irregular enhancement with delayed washout on contrast-enhanced image. A one-piece modified orbitozygomatic approach was performed and a total en block resection was achieved. The bone flap was fixed with titanium miniplates and screws, the temporal muscle and the skin were closed in a standard fashion. The patient did not present any new deficit in the postoperative period. The patient had good functional and cosmetic outcomes with resolution of proptosis, restoration of eye movements, and improvement of visual acuity in the 3-month follow-up. Postoperative MRI showed total resection. CONCLUSION: The orbitozygomatic approach for large orbital cavernous hemangioma provides satisfactory orbital decompression and large working space, reduces traction, and increases visualization and freedom to dissect small vessels and nerves that may be tightly attached to the tumor pseudocapsule.

Hypoplasia of C1's posterior arch: Is there an ideal anatomical classification?

BACKGROUND: Congenital anomalies of the atlas are rare and usually occur in conjunction with other congenital variants. They include a wide spectrum of anomalies ranging from clefts to hypoplasia or aplasia of its arches that may contribute to spinal cord compressive syndrome. CASE DESCRIPTION: A 54-year-old male presented with the sudden onset of a severe quadriparesis and loss of proprioception after a minor fall. The magnetic resonance (MR) scan showed cord compression at the C1 level attributed to C1 arch hypoplasia. Two months following a decompressive C1 laminectomy without fusion, and the patient was symptom free. CONCLUSION: Posterior C1 arch hypoplasia is a rare anomaly that can contribute to cervical cord compression and myelopathy. The optimal surgical management may include, as in this case, a posterior decompression without fusion.

Tailored Anterior Clinoidectomy: Beyond the Intradural and Extradural Concepts.

Anterior clinoidectomy (AC) is a key microsurgical step for the safe and successful management of parasellar pathologies that involve the anterior clinoid process (ACP) and the optic canal. Traditionally, extra and intradural ACs are performed separately according to the surgeon's experience or preference. The objective is to present and discuss the tailored AC concept through illustrative cases. We conducted a retrospective record review of three patients who underwent AC as a surgical step for the treatment of parasellar pathologies that involve the ACP and optic canal. A review of the relevant literature on AC was performed in the PubMed, LILACS, and SciELO databases. In all three cases, the pterional craniotomy was the preferred approach for AC. Case 1, a 47-year-old female patient with type III anterior clinoidal meningioma, underwent a tailored intradural technique (optic canal unroofing) with total tumor resection and complete visual recovery. Case 2, a 63-year-old female patient with a complex type II anterior clinoidal meningioma with extensive hyperostosis of the ACP, underwent a hybrid AC technique with complete removal of the tumor and visual improvement. Case 3, a 62-year-old female, underwent a tailored intradural AC for clipping an incidental carotid-ophthalmic aneurysm. Tailored AC aims to provide adequate exposure with less risk of neurovascular injury, allowing enough space to safely treat parasellar lesions. The type, size, and location of the lesion, as well as the surgeon's experience, should always be considered for surgical planning.

Intraparenchymal subependymoma: Case report and literature review.

BACKGROUND: Intracranial subependymomas are rare slow-growing benign tumors typically located in the ventricular system, accounting for 0.07-0.7% of all intracranial neoplasms. Intraparenchymal subependymoma is extremely rare lesions, imposing a challenging diagnosis and management. CASE DESCRIPTION: We describe a case of a supratentorial intraparenchymal mass on left occipital lobe in a 26-year-old woman with progressive headache and visual impairment. Differential diagnosis mainly included gliomas, neuronal-glial tumors, ependymoma, and subependymoma. Complete surgical resection was performed and histopathology analysis confirmed diagnosis of subependymoma. Despite its benign behavior the Ki67/MIB-1 labeling index assessed by immunohistochemistry was 5%. After 1 year of follow-up she was free of tumor recurrence. CONCLUSION: Intraparenchymal subependymoma is extremely rare tumors and literature review showed only 11 cases reported. In general, they are misdiagnosed as other tumors, so careful attention on clinical and radiological features must be taken when looking at a tumor close to the ventricular system, even though it does not have any obvious direct connection to it. Despite its benign nature, total removal must be attempted given that there are reports of recurrence, especially in partially removed tumors with high proliferation index. The role of adjuvant therapy is still limited and new treatment options are being developed as our knowledge on biological and molecular characteristics advances.

Endoscopic Endonasal Approach to Foramen Magnum Meningioma: Two-Dimensional Surgical Video.

Even for the most experienced neurosurgeons, foramen magnum meningiomas represent a surgical challenge owing to their delicate position surrounded by the brainstem, lower cranial nerves, and vertebral arteries. The treatment goal is gross total resection, but choosing the most appropriate approach is crucial. Basically, 3 surgical approaches are commonly used: posterolateral approach (far-lateral), anterolateral approach (extreme-lateral), and posterior midline approach. However, over the years, skull base surgery has evolved from standard open craniotomies to the use of microscopes and, more recently, to the development of endoscopic techniques. The endoscopic endonasal approach (EEA) permits a direct extradural route without brain retraction and shorter postoperative recovery. In contrast to the oral route, the soft palate and retropharyngeal soft tissues are preserved, allowing patients to resume a regular diet on the first postoperative day. Despite the advantages, the EEA is yet not widely used for treating foramen magnum meningiomas, even in cases where EEA use is possible. The EEA is feasible especially in cases with no vascular encasements and with a limited inferior extension allowing minimal manipulation of lower cranial nerves. Care must be taken with tumors with a more lateral and caudal extension (below the tip of the odontoid process), when a far lateral approach may be the best approach. In this surgical Video 1, we present the surgical details with a stepwise narrative of the EEA for ventrolateral foramen magnum meningiomas through an illustrative case of a 48-year-old woman. Institutional informed consent was obtained for surgery and publication of this video.

Cavernous Sinus Hemangioma: Surgical Aspects.

Resection of lesions in the cavernous sinus remains a challenge to neurosurgeons due to its complex anatomy. This video (Video 1) presents the most relevant landmarks of the cavernous sinus region, helping to understand the surgical anatomy. A 55-year-old female presented with diplopia, partial ptosis, and facial dysesthesia in the left ophthalmic territory. Magnetic resonance imaging revealed a lesion in the left cavernous sinus. Microsurgical resection was performed through an approach that included a fronto-orbital craniotomy, an extradural clinoidectomy, and intradural resection of the lesion through the anteromedial triangle. This maneuver expands the optic-carotid and carotid-oculomotor space, therefore the operative corridor.1,2 Both the carotid and optic nerves are untethering and can be gently and safely mobilized. The result of the histopathologic study was hemangioma. Despite the complex anatomy and surgical challenges, it is possible to treat lesions in the cavernous sinus region without causing major deficits, mainly in the nonmeningioma tumors. This is why it is important to choose a safe route to the sinus, such as the anteromedial or Parkinson triangle.3.