A Neuroenteric Cyst of the Cavernous Sinus: A Case Report.

Background Neuroenteric cysts (NECs) are benign lesions mostly found as intradural extramedullary lesions in the cervicothoracic spinal cord. NECs in the cavernous sinus are very rare. To the best of our knowledge, this is only the second reported case and the first in an adult. Presentation We present a left cavernous sinus NEC in a 75-year-old female with gradually worsening headache and facial pain unresponsive to medical treatment. Imaging revealed a cystic mass lesion in the left cavernous sinus encasing the distal petrosal and cavernous segment of the internal carotid artery. Initial differential diagnoses included more common pathologies located near the cavernous sinus, including cystic schwannoma, craniopharyngioma, and dermoid and epidermoid tumors. The patient underwent a left pterional craniotomy with an extradural transcavernous approach for surgical exploration and possible resection of this mass lesion. Histopathology revealed an NEC lined with benign respiratory-type epithelium. Postoperative imaging revealed gross total tumor resection. The patient remained neurologically intact with complete resolution of facial pain. Conclusion We present a rare pathology that can easily be misinterpreted as other types of lesions. NECs should be kept in mind for differential diagnosis of cavernous sinus cystic lesions. The surgical aim should be maximal safe excision.

Safety and efficacy of microsurgery for complex cranial pathologies in the ultra-geriatric population.

OBJECTIVE: The global increase in the "ultra-geriatric" population (aged 80 years and older) has led to higher demand for neurosurgical procedures in this vulnerable population. The objective was to evaluate the safety and efficacy of advanced microsurgical procedures on ultra-geriatric patients, in our modern era of neurosurgery, anesthesiology, and advanced medical care. METHODS: The study examined 66 complex cranial procedures, performed on 65 ultra-geriatric patients, who constituted 3.8% of the 4461 consecutive neurosurgical procedures performed by a single neurosurgeon over 14-years in a tertiary care university hospital. Excluded from this study were intra- or extra-axial spontaneous hematomas or traumatic brain injuries, infections, biopsy-only cases and carotid endarterectomies. RESULTS: The most common indication for surgery for the 66 complex cranial procedures were meningiomas (23.9%), followed by gliomas (17.9%), and metastatic brain tumors (17.9%). Postoperative complications occurred in seven procedures (10.60%). No patient deaths were directly caused by intra- or postoperative events, and only one 30-day mortality occurred. All deceased patients had a statistically significant higher American Society of Anesthesiologists (ASA) class (p = 0.024). However, there was no significant correlation between ASA class and modified Rankin scale at discharge (p = 0.238). CONCLUSION: With the aging global population and increasing life expectancy, the number of ultra-geriatric patients with complex pathologies seeking advanced microsurgical treatment is growing. Therefore, neurosurgeons are confronting a growing number and variety of complex pathologies in ultra-geriatric patients in their daily practice. Regardless of advanced age, microsurgery provides safe and effective treatment, with age alone not being a barrier to proper neurosurgical treatment when other risk factors are adequately modified.

Microsurgical resection of a large petroclival meningioma via translabyrinthine approach combined with middle fossa craniotomy.

Petroclival meningiomas arise from the upper two-thirds of the clivus at the petroclival junction and are reached via various approaches. As petroclival meningiomas expand, they displace the brainstem and basilar artery toward the contralateral side. Because of their proximity to critical structures and deep skull base location, surgical treatment is challenging. Although several approaches have been introduced, their rationales vary. Herein, the authors demonstrate microsurgical resection of a large petroclival meningioma via a translabyrinthine approach combined with middle fossa craniotomy. For each approach, the pros and cons should be carefully evaluated based on the patient's presentation and lesion characteristics. The video can be found here: https://stream.cadmore.media/r10.3171/2022.1.FOCVID21253.

Transcavernous Approach for Gross Total Resection of a Dumbbell-Shaped Giant Trigeminal Schwannoma.

Trigeminal schwannomas are rare nerve sheet tumors that represent the second most common intracranial site of occurrence after vestibular nerve origins. Microsurgical resection of giant dumbbell-shaped trigeminal schwannomas often requires complex skull base approaches. The extradural transcavernous approach is effective for the resection of these giant tumors involving the cavernous sinus. The patient is a 72-year-old man with headache, dizziness, imbalance, and cognitive decline. Neurological examination revealed left-sided sixth nerve palsy, a diminished corneal reflex, and wasting of temporalis muscle. Magnetic resonance imaging (MRI) showed a giant homogeneously enhancing dumbbell-shaped extra-axial mass centered within the left cavernous sinus, Meckel's cave, and the petrous apex, with extension to the cerebellopontine angle. There was a significant mass effect on the brain stem causing hydrocephalus. Computed tomography (CT) scan showed erosion of the petrous apex resulting in partial anterior autopetrosectomy ( Figs. 1 and 2 ). The decision was made to proceed with tumor resection using a transcavernous approach. Gross total resection was achieved. The surgery and postoperative course were uneventful, and the patient woke up the same as in the preoperative period. MRI confirmed gross total resection of the tumor. The histopathology was a trigeminal schwannoma, World Health Organization (WHO) grade I. The patient continues to do well without any recurrence at 15-month follow-up. This video demonstrates important steps of the microsurgical skull base techniques for resection of these challenging tumors. The link to the video can be found at https://youtu.be/TMK5363836M.

Role of Extradural Clinoidectomy and Optic Unroofing in Resection of an Anterior Clinoidal Meningioma with Encasement of the Internal Carotid Artery and Its Branches.

Anterior clinoidal meningiomas (ACMs) remain a major neurosurgical challenge. The skull base techniques, including extradural clinoidectomy and optic unroofing performed at the early stage of surgery, provide advantages for improving the extent of resection, and thereby enhancing overall outcome, and particularly visual function. Additionally, when the anterior clinoidal meningiomas encase neurovascular structures, particularly the supraclinoid internal carotid artery and its branches, this further increases morbidity and decreases the extent of resection. Although it might be possible to remove the tumor from the artery wall despite complete encasement or narrowing, the decision of whether the tumor can be safely separated from the arterial wall ultimately must be made intraoperatively. The patient is a 75-year-old woman with right-sided progressive vision loss. In the neurological examination, she only had light perception in the right eye without any visual acuity or peripheral loss in the left eye. MRI showed a homogeneously enhancing right-sided anterior clinoidal mass with encasing and narrowing of the supraclinoid internal carotid artery (ICA). Computed tomography (CT) angiography showed a mild narrowing of the right supraclinoid ICA with associated a 360-degree encasement. The decision was made to proceed using a pterional approach with extradural anterior clinoidectomy and optic unroofing. The surgery and postoperative course were uneventful. MRI confirmed gross total resection ( Figs. 1 and 2 ). The histopathology was a meningothelial meningioma, World Health Organization (WHO) grade I. The patient continues to do well without any recurrence and has shown improved vision at 15-month follow-up. This video demonstrates important steps of the microsurgical skull base techniques for resection of these challenging tumors. The link to the video can be found at https://youtu.be/vt3o1c2o8Z0.

Transcavernous Resection of a Giant Extensive Chondrosarcoma with Endoscopic Assistance.

Chondrosarcomas are one of the major malignant neoplasms which occur at the skull base. These tumors are locally invasive. Gross total resection of chondrosarcomas is associated with longer progression-free survival rates. The patient is a 55-year-old man with a history of dysphagia, left eye dryness, hearing loss, and left-sided facial pain. Magnetic resonance imaging (MRI) showed a giant heterogeneously enhancing left-sided skull base mass within the cavernous sinus and the petrous apex with extension into the sphenoid bone, clivus, and the cerebellopontine angle, with associated displacement of the brainstem ( Fig. 1 ). An endoscopic endonasal biopsy revealed a grade-II chondrosarcoma. The patient was then referred for surgical resection. Computed tomography (CT) scan and CT angiogram of the head and neck showed a left-sided skull base mass, partial destruction of the petrous apex, and complete or near-complete occlusion of the left internal carotid artery. Digital subtraction angiography confirmed complete occlusion of the left internal carotid artery with cortical, vertebrobasilar, and leptomeningeal collateral development. The decision was made to proceed with a left-sided transcavernous approach with possible petrous apex drilling. During surgery, minimal petrous apex drilling was necessary due to autopetrosectomy by the tumor. Endoscopy was used to assist achieving gross total resection ( Fig. 2 ). Surgery and postoperative course were uneventful. MRI confirmed gross total resection of the tumor. The histopathology was a grade-II chondrosarcoma. The patient received proton therapy and continues to do well without recurrence at 4-year follow-up. This video demonstrates steps of the combined microsurgical skull base approaches for resection of these challenging tumors. The link to the video can be found at: https://youtu.be/WlmCP_-i57s .

Malignant Transformation of Recurrent Residual Cerebellopontine Angle Epidermoid Tumor: Significance of Clinical Vigilance and Long-Term Surveillance.

Epidermoid tumors (ET) are slow-growing masses where malignant transformations occur extremely rarely. Malignant transformation warning signs are the rapid-onset, progression, and recurrence of symptoms. The radiologic evidence for malignant transformation is contrast enhancement with rapid growth, observed with magnetic resonance imaging (MRI) or computed tomography scans. Here, we provide a case report of a 68-year-old woman with a long-standing history of left-sided cerebellopontine angle ET who presented with a recent worsening of symptoms, and MRI observation of new ET contrast enhancement. Surgical re-exploration and histopathologic confirmation are mandatory in this setting of recent symptom worsening and MRI observation of rapid mass growth.

The role of microsurgery for poor-grade aneurysmal subarachnoid hemorrhages in the endovascular era.

BACKGROUND: Poor-grade aneurysmal subarachnoid hemorrhage (PGASAH) is associated with high mortality and morbidity regardless of treatment. Herein, we re-evaluate the safety and efficacy of microsurgical treatment for managing PGASAH patients in the current endovascular era. METHODS: We retrospectively reviewed 141 consecutive patient records in a single institution who underwent microsurgical (n = 80) or endovascular (n = 61) treatment for PGASAH. RESULTS: Baseline characteristics were similar, except for more intracerebral hematomas (46.3% vs 24.6%, p = 0.009), fewer intraventricular hemorrhages (26.3% vs 59%, p < 0.001), and fewer posterior circulation aneurysms (5.1% vs 44.3%, p < 0.001) in the microsurgery group. Decompressive craniectomy (58.5% vs 24.6%, p < 0.001) and shunt-dependent hydrocephalus (63.7% vs 41%, p = 0.01) were more common for microsurgery, while procedural ischemic complications were less common (5% vs 24.6%, p = 0.001). Both early (12.5% vs 32.8%, p = 0.006) and late mortality rates (22.5% vs 39.3%, p = 0.041) were lower for microsurgery, and favorable 12-month outcomes (modified Rankin scale = 0-2) were better (62.5% vs 42.6%, p = 0.026). Multivariate analysis revealed that advanced age, neurological grade, modified Fisher grade, larger aneurysm size, rebleeding, and cerebral infarctions were independent predictors of poor outcome. Microsurgery fared marginally better than endovascular treatment (OR: 2.630, 95% CI: [0.991-6.981], p = 0.052). CONCLUSIONS: Timely and efficient treatment, either via open microsurgery or endovascular surgery, provided favorable outcomes for over half of PGASAH patients in this series. Therefore, early treatment should be offered to all PGASAH patients regardless of clinical and/or radiological factors. Microsurgery remains an effective treatment modality for selected PGASAH patients in the endovascular era.

Posterior Circulation Aneurysms.

Posterior circulation aneurysms have a higher tendency to rupture and become symptomatic in comparison to anterior circulation aneurysms. Current treatment modalities for aneurysms in these locations vary widely including microsurgical clipping, trapping with bypass, wrapping, and various endovascular methods such as coiling, balloon or stent-assisted coiling, flow diversion, and vessel sacrifice, among others.Overall, surgical versus endovascular treatment of posterior circulation aneurysms continue to be a controversial topic in cerebrovascular neurosurgery. At our center, multi-disciplinary assessments including surgeons capable of both endovascular and microsurgical treatments of these aneurysms are employed to guide the treatment strategies. As advancements in both fields are made, this will continue to be a topic for debate. Anatomy and individual patient's characteristics will dictate the correct approach and therefore proficiency in the microsurgical techniques required to treat these aneurysms will continue to be both relevant and important.

Neurotoxic Effects of Ammonia in a Patient With Ornithine Transcarbamylase Deficiency and Bilateral Brain Abscesses: Case Report.

Brain abscesses are a rare complication of dental procedures. High concentrations of ammonia in brain abscesses may increase vasogenic edema and other brain abscess symptoms. Ornithine transcarbamylase deficiency (OTCD) is an x-linked genetic disorder of the urea cycle associated with an increased risk of brain damage due to hyperammonia. During acute metabolic decompensations, due to stresses such as infection in OTCD patients, blood ammonia levels become moderately high. This, in turn, causes cerebral glutamine levels to increase and exacerbate cerebral edema and neurological symptoms. In this report, we present a 25-year-old woman with known partial OTCD who presented with bilateral brain abscesses 2 weeks after a wisdom tooth extraction. Neurotoxic effects of ammonia, from local ammonia formation in brain abscesses positive for streptococcus intermedius, or due to her OTCD, may have exacerbated the cerebral edema, which resulted in irreversible encephalopathy that lead to her death.

Demonstration of Microsurgical Technique and Nuances for the Resection of a Midbrain Tectal Glioma via the Transcollicular Approach: 3-Dimensional Operative Video.

Tectal gliomas are a rare subset of intrinsic brainstem lesions. The microsurgical resection of these lesions remains a major challenge.1,2 Transcollicular approaches on one side, via the superior or inferior colliculi or both, are neurologically well tolerated without obvious or major auditory or oculomotor consequences. However, any postoperative acute visually triggered saccadic abnormalities caused by iatrogenic superior colliculus damage generally resolve during the postoperative period, as other oculomotor structures compensate for these functions in unilateral lesions. In this surgical video, we present a 37-yr-old man with long-standing seizures, new onset headaches, progressive ataxic gait, and imbalance. Magnetic resonance imaging (MRI) showed a circumscribed nonenhancing dorsal midbrain cystic mass with compression on the aqueduct causing hydrocephalus. The lesion had a low signal intensity on T1-weighted images and a high signal intensity on T2-weighted images. The patient first underwent an endoscopic third ventriculostomy. Although his headaches greatly improved after the third ventriculostomy, he remained quite symptomatic in terms of gait imbalance and ataxia. The patient underwent a supracerebellar, infratentorial, transcollicular approach for resection of the tectal tumor. Simultaneously, motor and somatosensory evoked potentials were monitored. Both the surgery and the postoperative course were uneventful, with postoperative MRI showing gross total resection of the mass, and histopathology indicating a WHO (World Health Organization) grade I pilocytic astrocytoma. The patient continued to do well without recurrence at 2-yr follow-up. In this video, we demonstrate step-by-step microsurgical techniques for resecting these challenging tectal gliomas via the infratentorial-supracerebellar-transcollicular approach. The patient consented to the procedure and publication of his images.

Demonstration of Microsurgical Technique and Nuances for the Obliteration of Complex Intracranial Dural Arteriovenous Fistulas in Three Consecutive Cases: Operative Video.

An intracranial dural arteriovenous fistula (DAVF) is an uncommon acquired dural shunt between an artery and a vein without a parenchymal nidus. DAVF occlusion may be achieved using either endovascular or open surgical means. Combining both techniques is also frequently used in clinical practice. In this video, we present 3 patients with Borden type III, complex intracranial DAVFs. The first patient presented with intracranial hemorrhage and underwent a successful microsurgical obliteration of the fistula in the tentorium. Two other patients had DAVFs that were incidentally found. Both underwent embolization procedures, which did not result in complete DAVF obliteration. Both patients then subsequently underwent microsurgical obliteration of these DAVFs. All 3 patients had very good outcomes. In 2 of these cases, we performed indocyanine green video angiography to identify fistulous connections. As demonstrated in this Video 1, microsurgical obliteration of DAVFs is relatively straightforward. This provides a valuable treatment option of some selected DAVFs and should be considered as a primary initial treatment option of complex DAVFs in certain locations. Open surgical obliteration is the best possible, most durable, and most effective therapeutic option when there are failures or shortcomings with endovascular management.

Trigeminal Neuralgia Caused by Vascular Compression from the Petrous Carotid Artery with Bony Erosion and Meckel Cave Encephalocele: Clinical Imaging with Surgical Video.

Trigeminal neuralgia (TN) is most commonly caused by neurovascular compression of the superior cerebellar artery. We present the first reported TN case where nerve compression was caused by the petrous internal carotid artery in the vicinity of a Meckel cave (MC) encephalocele. The patient underwent a pterional craniotomy for decompression of the gasserian ganglion and trigeminal nerve branches. All symptoms were resolved post surgery. We surmise that the principal cause of the TN was vascular compression from an exposed petrous internal carotid artery in the presence of an encephalocele. Causation was irrespective of whether the dehiscence in the petrous apex was a congenital defect or associated with destruction from the encephalocele. Based on this observation, we recommend that surgeons carefully consider all possible causes of patient symptoms as they prepare a meticulous dissection plan to avoid damage to surrounding neurovascular structures.

Surgical Strategies for Cerebral Revascularization in Patients with Limited Bypass Conduit Options and Unexpected Intraoperative Difficulties.

BACKGROUND: Cerebral bypass procedures are complex and require substantial experience and skills and thorough preoperative planning. Cerebrovascular surgeons face increasingly complex bypass cases because most routine cases are managed by endovascular means, and because increasing numbers of patients have complex medical problems that affect available and suitable bypass conduit options. We report the cases of several patients undergoing cerebral bypass with limited bypass conduit alternatives, in whom there were unexpected intraoperative difficulties requiring complex solutions. METHODS: The neurological surgery department database was reviewed to identify patients who had undergone cerebral bypass procedures during a 13-year period in whom there were limited available bypass conduits, and in whom unexpected intraoperative difficulties were encountered during cerebral bypass. RESULTS: Patient outcomes and graft patency were evaluated for 13 patients including 6 with ischemia, 3 with giant aneurysms, 2 with mycotic aneurysms, 1 with dissecting aneurysm, and 1 with gunshot-induced pseudoaneurysm. Median duration of follow-up was 43 months. In 12 of 13 patients, bypass graft/grafts were patent on the last computed tomography angiogram. In 1 patient, a prophylactic bypass procedure, the graft was not filling, probably because of lack of demand. Two patients died during follow-up of unrelated causes. CONCLUSIONS: Cerebrovascular surgeons should be versatile in dealing with patients with complex bypass. When there are limited available conduit options, we find that collaboration with other surgical specialties (e.g., plastics and vascular) is helpful. In patients in whom extreme intraoperative difficulties are expected, thorough preoperative planning with multiple backup plans should be exercised, as described in this report.

Intraoperative Shortening of Aneurysm Clips: Revisiting an Old Technique in a New Era.

BACKGROUND: It can sometimes be challenging to find a suitable clip to treat an unusual aneurysm, or when the surrounding anatomy is unusual, especially in resource-limited environments. We describe a method to modify aneurysm clips based on the method originated by Sugita et al in 1985. Herein clip modification (Clip-Mod) is used to treat anatomically difficult anterior communicating artery aneurysms. METHODS: The Department of Neurological Surgery database was reviewed to find aneurysm patients treated using modified aneurysm clips. Clip-Mod was performed during surgery by shortening the tines of titanium aneurysm clips by abrasion applied from the side of a standard 3-mm surgical diamond drill bit under constant irrigation. Note that the thickness of the tines and the clip spring were not modified or contacted by the drill. RESULTS: Four cases used modified aneurysm clips, from 648 total clip-treated aneurysms (0.6%) by 2 surgeons over a 14-year period. Three patients presented with subarachnoid hemorrhages that were determined to be due to anterior communicating artery aneurysms. One patient presented with an incidental unruptured anterior communicating artery aneurysm. All 4 patients were treated with 3-mm titanium clips shortened intraoperatively to 1- to 2-mm lengths, to achieve aneurysm obliteration without stenosing parent or perforating vessels. CONCLUSIONS: All 4 patients have done well clinically with no reoccurrences after 2-6 years' follow-up, which included angiographic evaluation. The use of this "Clip-Mod" technique thus appears useful for anterior communicating artery aneurysms. Clip-Mod could also be considered for treating other aneurysms when the "perfect" length clip is not available.

From Ibni Sina (Avicenna) to Present, History of International Fellowship and Observership: University of Wisconsin-Madison Experience.

Since the inception of the International Fellowship (IF) Program in the Department of Neurological Surgery at the University of Wisconsin-Madison in 2006, training has been provided to 219 residents, neurosurgeons, and medical students from 18 countries and five continents. These IFs took a long academic and geographic journey to improve their skills in patient care. The advanced training, they received lead to 14 of these IF neurosurgeons to return to their hometowns with higher academic appointments, including two chairmen, seven professors, two associate professors, two assistant professors, and one consultant neurosurgeon. An additional measure of success for the IF Program is that fellows continue to communicate with their mentors and with their prior fellow international colleagues long after their fellowship ends.

Spontaneous Subarachnoid Hemorrhage From a Pure Pial Arterial Malformation in the Lateral Cerebellomedullary Junction: Clinical Images with a Surgical Video.

Pure pial arterial malformations (PAMs) are poorly understood owing to the limited number of reported cases. Because PAMs have been thought to have a benign natural history, they have generally been managed conservatively, unlike arteriovenous malformations or arteriovenous fistulas. In the present report, we have described a spontaneous subarachnoid hemorrhage from the rupture of a PAM at the cerebellomedullary junction. This hemorrhage was surgically treated using clip trapping.

Aggressive, Multidisciplinary Staged Microsurgical Resection of a Giant Cervicomedullary Junction Chordoma.

Chordomas of the cranial base are locally destructive tumors since they are surrounded by significant complex neurovascular structures. Thus, their surgical removal is challenging, recurrence rates are high, and their therapeutic strategies remain controversial. In this video, we present a 47-year-old man with a recent onset of swallowing difficulties, hoarseness, and weight loss for several weeks. In the neurological examination, he had complete paralysis of the 9th, 10th, 11th, and 12th cranial nerves. Magnetic resonance imaging (MRI) showed a heterogeneously enhancing expansile invasive mass lesion centered within the clivus and involving the C1, the occipitocervical junction, the retropharynx, and the hypoglossal canal. The decision was made to proceed with multiple staged surgeries. In the first surgical stage, we performed a mastoidectomy with the infralabyrinthine approach to perform a test clip ligation of the sigmoid sinus and to resect the tumor component that extended into the infralabyrinthine space. In the second stage, we performed a far-lateral transcondylar approach for tumor resection and occipitocervical fusion. In the third stage, we used a transoral approach with endoscopic assistance to complete the excision of the remaining tumor in the retropharyngeal space and anterior aspect of C1 and C2 bodies that were not accessible in the first two stages. The surgeries and postoperative course were uneventful. Postoperative MRI showed a gross total resection of the tumor. Histopathology indicated a chordoma. The patient subsequently received proton radiotherapy and has continued to do well without recurrence at 14 months' follow-up. The link to the video can be found at: https://youtu.be/uP9OSlKg_rE .

Delayed Onset Abducens Nerve Palsy following Uncomplicated Large Cystic Vestibular Schwannoma Resection: Case Report.

Although delayed facial palsy after vestibular schwannoma (VS) surgery is a poorly understood but a well-known phenomenon, other delayed cranial nerve palsies in the cerebellopontine angle have not been reported after VS surgery. In this report, we describe a 54-year-old woman with a large cystic VS who experienced double vision and a new delayed onset right abducens nerve (AbN) palsy, 3 weeks after gross total resection of VS via a translabyrinthine approach. To the best of our knowledge, this is the first report describing delayed isolated AbN palsy after uncomplicated VS surgery. Magnetic resonance imaging findings and the management of this complication following VS surgery are discussed in this case report.

Microsurgical Gross Total Resection of Foramen Magnum Meningioma via Far Lateral Approach.

Foramen magnum meningiomas are one of the most challenging tumors for skull base neurosurgeons due to their proximity to critical neurovascular structures. The far-lateral approach demonstrated here facilitates access to lesions involving the anterior portion of the foramen magnum. In this video, we present a 62-year-old woman with hand numbness and weakness. The patient had significant difficulty in fine motor movements of both hands. In the neurological examination, she had a significant right-hand intrinsic muscle weakness and mild quadriparesis. Magnetic resonance imaging (MRI) showed a dural-based homogeneously enhancing extra-axial mass in the anterior foramen magnum with a significant mass effect on the brain stem and the upper cervical cord. The decision was made to proceed with a far lateral transcondylar skull base approach including partial C1 laminectomy. The surgery and postoperative course were uneventful. The postoperative MRI showed gross total resection of the mass. The histopathology indicated a WHO (World health Organization) grade-I meningioma. The patient's postoperative course was uneventful. She improved to normal neurological function within several weeks and continues to do well without recurrence at 20 months' follow-up. In this video, we demonstrated important steps for the microsurgical resection of these challenging lesions. The link to the video can be found at: https://youtu.be/_nuX2Y7YU9w .