Cranio-Orbital Approach and Decompression of the Optic Nerves: A 2-Stage, 4-by-4-Step Approach to Improve Vision in Sellar and Parasellar Lesions.

BACKGROUND AND OBJECTIVES: Despite advances in cranial base techniques, surgery of the sellar and parasellar regions remains challenging because of complex neurovascular relationships. Lesions within this region frequently present with progressive visual deterioration caused by distortion and compression of the optic chiasm and nerves. In addition to the direct mass effect from mechanical forces acting on the optic apparatus, these lesions alter blood supply and reduce vascular perfusion, prompting surgical treatment to remove the lesion, alleviate compression, and improve blood flow to the optic nerve. We sought to describe a 2-stage, 4-by-4-step approach, broken down and described as a "four-by-four" technique for optic apparatus decompression and a wide approach to different sellar and parasellar lesions. METHODS: We describe the operative nuances and key anatomic points in the microsurgical removal of sellar and parasellar lesions. The technique is illustrated with examples of different cases with pre- and follow-up MRI imaging and a brief overview of visual outcomes. RESULTS: The described technique has been demonstrated in various lesions in 5 patients. Patients presented with bilateral visual loss in 4 (80.0%) cases and with unilateral visual loss in 1 (20.0%) case. Improvement in visual function was noted in all cases, confirmed with visual acuity and visual field testing. DISCUSSION: The transcranial approach ("from above") remains an important surgical option for patients with excellent exposure and visualization of the sellar and parasellar regions. It permits early access to the optic canal for careful microsurgical decompression and relaxation of the optic nerve to preserve and improve its microvascularization and ultimately vision. CONCLUSION: The authors augmented the 2-stage, 4-by-4-step technique of decompression with elaborate illustrations of diverse sellar and parasellar lesions to demonstrate the versatility of this approach.

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.

Accessory Nerve Schwannoma with Medulla Oblongata Compression: Microsurgical Resection by Far Lateral Suboccipital Transcondylar Approach: 2-Dimensional Operative Video.

Schwannomas overall account for approximately 8% of primary brain tumors, with the majority of them arising from the vestibular nerves.1,2 Non-vestibular schwannomas are considered rare, particularly ones arising from the accessory nerve, constituting only around 4% of craniovertebral junction schwannomas.3,4 The far lateral approach and its variations is an important tool in the armamentarium of skull base neurosurgeons. It allows adequate exposure for accessing ventral and ventrolateral lesions of the craniocervical junction.5-13 A 60-year-old female patient presented with a 3-month history of difficulty walking and progressive right-sided weakness. Magnetic resonance imaging demonstrated an extra-axial solid lesion at the craniocervical junction with significant enhancement on post-contrast imaging. The lesion was ventrolateral to the medulla, causing compression, displacement, and peritumoral edema. The patient consented to the procedure and underwent a far lateral suboccipital craniotomy with C1 hemilaminectomy in a lateral position. Tumor origins were identified at the left accessory nerve rootlet. The patient's postoperative course was uneventful. Follow-up magnetic resonance imaging revealed gross total resection and complete resolution of hemiparesis 3 months after the surgery. Microsurgical resection of tumors at the craniocervical junction is challenging. Preoperative planning and tailoring the approach are essential in the decision-making process to safely perform surgery. This video demonstrates, in detail, the steps, relevant anatomy, and technical nuances for accessory nerve schwannoma ressmoval. To the best of our knowledge, this is the first operative video showing the resection of a pure accessory nerve schwannoma with compression of the medulla. Under our institutional ethical review board regulations, approval was not necessary.

Cranio-Orbital Pretemporal Approach for Microsurgical Resection of Hypothalamic Rosette Forming Glioneuronal Tumor with Reversal of Preoperative Blindness: 2-Dimensional Operative Video.

The hypothalamic region is susceptible to involvement of several processes.1 Lesions in this region remain challenging for surgical access and treatment. Strategies include both endoscopic and microsurgical approaches.2 A cranio-orbital approach with extradural clinoidectomy and optic canal unroofing provides the necessary corridor to visualize and decompress the optic nerve/chiasm and remains an important tool in achieving complete tumor resection with favorable functional and visual outcomes.3-12 Endoscope assistance in transcranial surgery is well established, used to provide direct visualization of hidden adjacent tissues.13 A 25-year-old woman presented with headache and progressive visual loss to blindness (hand waving and light perception) on admission. Magnetic resonance imaging demonstrated a 28-mm-diameter tumor in the hypothalamic region with no significant postcontrast enhancement. She underwent right cranio-orbital craniotomy, extradural anterior clinoidectomy, and optic canal unroofing with a 2-mm high-speed diamond drill and copious irrigation. After ipsilateral falciform ligament release, the tumor capsule was coagulated, sharply opened, and resected in a piecemeal fashion. Endoscopic assistance warranted the removal of hidden parts and confirmed tumor removal. Histopathology and next-generation sequencing confirmed the diagnosis of rosette-forming glioneural tumor. Follow-up revealed gross total tumor removal on magnetic resonance imaging and complete recovery of visual function as per ophthalmologist examination. Rosette-forming glioneural tumors are considered rare and classified as World Health Organization grade I tumors usually found in the fourth ventricle.14 To our knowledge, we present the first operative video (Video 1) demonstrating the removal of rosette-forming glioneural tumor in the hypothalamic region with endoscopic assistance.

Cranioorbital Pretemporal Skull Base Approach with Anterior Clinoidectomy for Removal of Large Left Clinoid Meningioma: "Unwrapping" Encircled Internal Carotid Artery and Decompressing Optic Nerve: 2-Dimensional Operative Video.

Clinoidal meningiomas are meningiomas arising from or in the vicinity of the anterior clinoid process.1 Despite advanced microsurgical techniques, clinoidal meningiomas remain challenging.2 Extradural anterior clinoidectomy with optical unroofing remains an important tool in skull base surgery, which provides a safe operative corridor, facilitating greater extent of resection and enhancing overall outcome, particularly visual function.2-13 A 66-year-old woman presented with history of visual disturbances. Magnetic resonance imaging revealed a dural-based tumor consistent with a large left clinoidal meningioma, with tumor wrapping (encircling) around the left trunk and internal carotid artery (ICA) bifurcation, elevating the left middle cerebral artery M1 segment, and invading the left optic canal. Left cranio-orbital craniotomy with pretemporal exposure was used (Video 1).1,9 A high-speed diamond drill with irrigation completed the extradural anterior clinoidectomy and optical canal unroofing. Use of a 1-mm Kerrison rongeur should be done with utmost care. The tumor was unwrapped via meticulous piecemeal removal. Final dissection and ICA unwrapping was done when the tumor was debulked enough that dissecting it off the artery was safe and under less tension. Due to its obscurity, final decompression of the left optic nerve with incision and opening of the falciform ligament was performed at the end of the procedure.10 Postoperative neuro-ophthalmologic examination showed a grossly unchanged left visual field with some visual acuity improvement. Resection of tumor encircling the ICA has been described previously;14 however, to the best of our knowledge, this is the first video describing removal of a tumor surrounding the ICA (perfomed by senior author K.I.A.), essentially "unwrapping" the left ICA trunk and its bifurcation. The patient consented to publication.

An integrative survival analysis and a systematic review of the cerebellopontine angle glioblastomas.

Glioblastomas presenting topographically at the cerebellopontine angle (CPA) are exceedingly rare. Given the specific anatomical considerations and their rarity, overall survival (OS) and management are not discussed in detail. The authors performed an integrative survival analysis of CPA glioblastomas. A literature search of PubMed, Scopus, and Web of Science databases was performed per PRISMA guidelines. Patient data including demographics, clinical features, neuroimaging, management, follow-up, and OS were extracted. The mean age was 39 ± 26.2 years. The mean OS was 8.9 months. Kaplan-Meier log-rank test and univariate Cox proportional-hazards model identified hydrocephalus (log-rank, p = 0.034; HR 0.34; 95% CI 0.12-0.94; p = 0.038), chemotherapy (log-rank, p < 0.005; HR 5.66; 95% CI 1.53-20.88; p = 0.009), and radiotherapy (log-rank, p < 0.0001; HR 12.01; 95% CI 3.44-41.89; p < 0.001) as factors influencing OS. Hydrocephalus (HR 3.57; 95% CI 1.07-11.1; p = 0.038) and no adjuvant radiotherapy (HR 0.12; 95% CI 0.02-0.59; p < 0.01) remained prognostic on multivariable analysis with fourfold and twofold higher risk for the time-related onset of death, respectively. This should be considered when assessing the risk-to-benefit ratio for patients undergoing surgery for CPA glioblastoma.

Anterior Transpetrosal-Transtentorial Approach for Removal of a Large Petrous Apex Meningioma: 2-Dimensional Operative Video.

Video 1 demonstrates the microsurgical resection of petrous apex meningioma. Even small lesions by general rules are regarded as large due to the delicate nature of anatomic localization. The intricate relationship between the tumor and vascular supply of the brainstem and interposition of cranial nerves makes them challenging lesions to resect.1 A 67-year-old female patient presented with a 6-month history of trigeminal neuralgia in the V2 and V3 branches. She underwent gross total resection of an extraaxial homogenously enhancing dural-based tumor in the right petroclival region, consistent with a large (3-4.5 cm) petrous apex meningioma, the least frequently reported subtype of petroclival meningiomas.2,3 Skull base approaches for surgical resection of these tumors include high-speed drilling of petrous bone to create a corridor that facilitates access to the lesion.1 Preserved hearing with suprameatal extension of the infratentorial component and absence of a tumor laterally and inferiorly to the internal auditory canal provided the rationale for selecting a subtemporal approach combined with anterior petrosectomy.1,4,5 Identification of anatomic landmarks of the Kawase triangle is the key first step for determining the bony removal corridor, outlined by the greater superficial petrosal nerve, the arcuate eminence, and the petrous ridge.1,6 An important step in surgical removal is the devascularization of feeding arteries arising from the meningohypophyseal trunk.7,8 Subsequent piecemeal removal and circumferential detachment while making sure to preserve major vascular and nerve elements is crucial for successful removal. The patient consented to the procedure. The postoperative course was uneventful. The patient's trigeminal neuralgia completely regressed with no new neurologic deficit.

Case Report: Atypical Solitary Brain Metastasis: The Role of MR Spectroscopy In Differential Diagnosis.

Background: Metastatic brain tumors are typically located at the cerebral hemispheres or the cerebellum and most frequently originate from primary breast or lung tumors. Metastatic lesions are usually associated with blood-brain barrier disruption, solid or ring-like contrast enhancement, and perilesional vasogenic edema on brain imaging. Even in cases where metastases are predominantly cystic, enhancement of the minor solid component can be detected. In contrast, non-enhancing secondary brain tumors were only reported in a patient after antiangiogenic treatment with bevacizumab. Case report: We report a case of a 54-year-old male who presented with left-sided weakness and multiple seizures. Brain magnetic resonance imaging revealed a T2-weighted heterogeneous solid tumor in the right frontoparietal parasagittal region, with no apparent enhancement on T1-weighted post-contrast images and no evident perilesional edema. Further MRS analysis revealed markedly increased choline and lipid peaks. The patient underwent craniotomy for tumor removal. Histopathology revealed findings consistent with metastatic non-microcellular neuroendocrine lung cancer. positron emission tomography/computed tomography (PET/CT) revealed a stellate lesion within the right upper lung lobe, compatible with primary lung cancer. Conclusion: Non-enhancing brain metastatic tumors are rarely reported in the literature, usually following antiangiogenic treatment. Here, we report the first ever case of a non-enhancing metastatic brain tumor with no prior history of antiangiogenic treatment, with particular emphasis on the importance of MRS analysis in atypical brain lesions.

Venous thromboembolic and hemorrhagic events after meningioma surgery: A single-center retrospective cohort study of risk factors.

Microsurgical resection of meningiomas in a majority of cases leads to a favorable outcome. Therefore, severe postoperative adverse events are less acceptable. The main purpose of this study was to investigate the incidence of symptomatic venous thromboembolism (VTE) and hemorrhagic complications in patients after operative treatment of intracranial meningiomas and to identify the risk factors in this patient subgroup. Of 106 patients undergoing elective craniotomy for meningioma overall incidence of symptomatic VTE was noted in 5.7% (six patients). For the risk-factor analysis older age (57.20 ± 11.60 vs. 71.00 ± 0.90 years, p < 0.001), higher body mass index (27.60 ± 4.80 vs. 33.16 ± 0.60 kg/m2, p < 0.001), WHO grade II (3.00% vs. 33.33%, p = 0.02), lower intraoperative blood loss (466.00 ± 383.70 vs. 216.70 ± 68.30 mL, p < 0.001), bedridden status and neurologic deficit (0.00% vs. 33.33%, p = 0.003 and 38.00% vs. 100.00%, p = 0.004) were associated with greater VTE risk. No risk factors for hemorrhagic complications were identified on univariate analysis. In conclusion, the incidence of VTE in meningioma patients is not negligible. Identified risk factors should be taken into account in the decision-making process for chemoprophylaxis when the risk of bleeding decreases.

Primary Intraparenchymal Meningiomas: A Case Report and a Systematic Review.

BACKGROUND: Primary intraparenchymal meningiomas are exceedingly rare and often challenging to diagnose, given their misleading radiologic features. It is hypothesized that they arise from the cap cells of the pia mater that enter the brain via penetrating blood vessels during brain development. We systematically reviewed and analyzed previously reported features of primary intraparenchymal meningiomas in terms of radiography, presenting symptoms, and histopathology. METHODS: A literature search of the Web of Science and PubMed databases and crossed references was performed in March 2021, per PRISMA guidelines, with no restrictions regarding publication date. Data regarding demographic features, clinical, radiographic, and histopathologic characteristics were extracted. RESULTS: A total of 52 patients (including the reported case) were included in this review. The mean age was 21.1 years (range, 0.3-66 years) with a male/female ratio of 1.9:1. The most common localizations of intraparenchymal meningiomas were in the frontal (30.8%) and temporal (21.2%) lobes. Cyst formation was more readily observed and was noted in 51.4% of patients. Histopathology showed a higher incidence of World Health Organization grade II (14/52, 26.9%) and World Health Organization grade III (7/52, 13.5%) of primary intraparenchymal meningiomas. CONCLUSIONS: We present a comprehensive analysis of every reported primary intraparenchymal meningioma. Because of their rarity and capacity to mimic other more common intra-axial tumors, they represent a diagnostic challenge. This systematic review highlights the importance of paying attention to atypical intra-axial lesions, with a particular reflection on the discrepancy between clinical characteristics and imaging features.

Nocardial brain abscess mimicking lung cancer metastasis in immunocompetent patient with pulmonary nocardiasis: a case report.

Nocardia is a ubiquitous microorganism which can be the cause of local and disseminated infection in humans. Immunocompetent and immunocompromised patients both can be affected and Nocardia cyriacigeorgica was reported as a pathogen isolated in patients worldwide. In most cases, nocardiosis is present as pulmonary infection because inhalation is the primary way of bacterial exposure. Nocardial brain abscess occurs usually secondary to a septic focus elsewhere in the body. Considering the facts that the elderly population is growing, such as the number of immunocompromised patients together with high mortality rate in patients with nocardial infection of the central nervous system, we have to raise awareness of the possibility for this rare but potentially fatal condition. We present a case where nocardial abscesses of lung and brain were initially suspected as lung cancer with brain metastases. The patient was treated with a combination of surgical resection and antimicrobial therapy with good outcome.