Anterior Clinoidal Meningiomas Research Articles

Letter: Microsurgical Removal of an Anterior Clinoid Meningioma With Extensive Vascular Encasement: 2-Dimensional Operative Video.

Letter: Microsurgical Removal of an Anterior Clinoid Meningioma With Extensive Vascular Encasement: 2-Dimensional Operative Video.

In Reply: Microsurgical Removal of an Anterior Clinoid Meningioma With Extensive Vascular Encasement: 2-Dimensional Operative Video.

In Reply: Microsurgical Removal of an Anterior Clinoid Meningioma With Extensive Vascular Encasement: 2-Dimensional Operative Video.

Anterior clinoid meningiomas: surgical results and proposed scoring system to predict visual outcomes.

The authors report a single-surgeon experience with anterior clinoid meningiomas (ACMs) and propose a novel scoring system to predict visual outcomes based on preoperative risk factors. A cohort study of all ACMs that were surgically treated by a single surgeon between 2003 and 2021 was performed. Visual function was assessed by an ophthalmologist pre- and postoperatively. Based on the combination of visual fields and visual acuity, 4 visual grades were described. Favorable visual outcomes were defined as mild visual deficit or intact vision postoperatively. Unfavorable visual outcomes were defined as a severe or moderate visual deficit. Predictors of unfavorable visual outcomes were identified using multivariable logistic regression analysis. A scoring system was then created using the resulting β coefficient. A receiver operating characteristic curve analysis was performed to identify a cutoff point on the grading score for stratifying patients at risk for unfavorable visual outcomes. Fifty-two patients met all inclusion criteria. Twenty-five (48%) patients presented with intact vision, and 27 (51%) presented with some visual dysfunction. Postoperative favorable visual outcomes were achieved in 39 patients (75%). Among the 27 patients presenting with visual dysfunction, 14 (52%) experienced improvement after surgery. No new visual deficits were observed among the 25 patients with intact vision at baseline. Nine patients (17%) had a reversible complication. Multivariable analysis showed that severe preoperative visual deficit (OR 13.03, 95% CI 2.64-64.39; p = 0.002), radiographic evidence of optic nerve (ON) encasement (OR 4.20, 95% CI 1.06-16.61; p = 0.04), intraoperative evidence of ON invasion (OR 17.31, 95% CI 2.91-102.86; p = 0.002), an average ganglion cell layer thickness of ≤ 70 µm (OR 21.54, 95% CI 2.94-159.04; p = 0.003), and an average retinal nerve fiber layer thickness of ≤ 80 µm (OR 13.68, 95% CI 1.91-98.00; p = 0.009) were associated with unfavorable visual outcome. The predictive score included the following factors: abnormal optical coherence tomography (OCT) findings, radiographic evidence of ON encasement by the tumor, and severe preoperative visual deficit. A score ≥ 4 of 6 points was demonstrated to be the cutoff associated with unfavorable visual outcome, with a sensitivity of 80%, specificity of 88%, positive predictive value of 80%, negative predictive value of 88%, and area under the curve of 0.847 (95% CI 0.674-1.0; p = 0.003). The authors have designed a practical and novel scoring system to predict visual outcomes in patients with ACMs. This scoring system may guide preoperative discussions with patients and timely surgical intervention to yield optimal visual function outcomes. Although most patients have excellent neurosurgical outcomes, severe baseline visual deficits, ON encasement, and characteristic OCT abnormalities are associated with unfavorable visual function after ACM resection.

Microsurgical Removal of an Anterior Clinoid Meningioma With Extensive Vascular Encasement: 2-Dimensional Operative Video.

Anterior clinoid meningiomas are challenging skull base lesions especially when they encase the internal carotid artery and its branches. According to the Al-Mefty classification, type I can originate in the subclinoid dura, type II on the superolateral aspect of the anterior clinoid process, and type III at the optic foramen, with type I being the most often associated with vascular encasement.1,2 We present the case of a 70-year-old patient who presented with visual disturbances revealing a large type I anterior clinoid meningioma encasing the internal carotid artery and its branches. The extended pterional approach with removal of the posterior part of the superior and lateral walls of the orbit3 was offered to the patient given the size of the tumor and the visual impairment. We present the main steps of the surgery: extended pterional approach with postero-lateral orbitotomy, extradural removal of the anterior clinoid process, and hyperosthosis. The meningioma is removed in a stepwise fashion starting in the less dangerous frontal sector of the tumor and ending in the supra cavernous and supra diaphragmatic sectors of the meningioma. The postoperative course was favorable, and at 3-month follow-up, the patient showed a significant visual improvement. Brain MRI showed a subtotal resection of the meningioma and no postoperative complications. We present the nuances and the surgical technique for anterior clinoid meningiomas with extensive vascular encasement. We discuss the factors predicting the preservation of the arachnoid planes reported in the literature.4 The patient consented to the procedure and to the publication of the images. Our Institutional Review Board ethics committee does not require an approval for this type of publication.

Double Trouble – An Anterior Clinoidal Meningioma with a Concurrent Right MCA Aneurysm

Although meningiomas and cerebral aneurysms are common intracranial pathologies, their coexistence in one patient is rare. We present a case of right anterior clinoid meningioma that has a concurrent right middle cerebral artery (MCA) aneurysm. A 55-year-old female complaining of right-sided visual loss was admitted to our department after magnetic resonance imaging (MRI) revealed a right anterior clinoid meningioma that was extending to sella turcica and expanded superiorly, compressing the optic chiasm. With a plan of transnasal transsphenoidal endoscopic excision, a preoperative computed tomography angiogram was obtained, per our protocol. This revealed an incidental 3 mm right MCA bifurcation aneurysm. Due to the possibility of postoperative aneurysm bleeding, the patient was operated on with a right-sided pterional craniotomy. After 5 days of postoperative follow-up, the patient was discharged without complications. The histopathological analysis confirmed the diagnosis of psammomatous meningioma. This case underlines the importance of preoperative planning and being vigilant for incidental findings that might cause fatal consequences.

Endonasal, supraorbital, and transorbital approaches: minimal access endoscope-assisted surgical approaches for meningiomas in the anterior and middle cranial fossae.

Minimally invasive endoscope-assisted approaches to the anterior skull base offer an alternative to traditional open craniotomies. Given the restrictive operative corridor, appropriate case selection is critical for success. In this paper, the authors present the results of three different minimal access approaches to meningiomas of the anterior and middle fossae and examine the differences in the target areas considered appropriate for each approach, as well as the outcomes, to determine whether the surgical goals were achieved. A consecutive series of the endoscopic endonasal approach (EEA), supraorbital approach (SOA), or transorbital approach (TOA) for newly diagnosed meningiomas of the anterior and middle fossa skull base between 2007 and 2022 were examined. Probabilistic heat maps were created to display the distribution of tumor volumes for each approach. Gross-total resection (GTR), extent of resection, visual and olfactory outcomes, and postoperative complications were assessed. Of 525 patients who had meningioma resection, 88 (16.7%) were included in this study. EEA was performed for planum sphenoidale and tuberculum sellae meningiomas (n = 44), SOA for olfactory groove and anterior clinoid meningiomas (n = 36), and TOA for spheno-orbital and middle fossa meningiomas (n = 8). The largest tumors were treated using SOA (mean volume 28 ± 29 cm3), followed by TOA (mean volume 10 ± 10 cm3) and EEA (mean volume 9 ± 8 cm3) (p = 0.024). Most cases (91%) were WHO grade I. GTR was achieved in 84% of patients (n = 74), which was similar to the rates for EEA (84%) and SOA (92%), but lower than that for TOA (50%) (p = 0.002), the latter attributable to spheno-orbital (GTR: 33%) not middle fossa (GTR: 100%) tumors. There were 7 (8%) CSF leaks: 5 (11%) from EEA, 1 (3%) from SOA, and 1 (13%) from TOA (p = 0.326). All resolved with lumbar drainage except for 1 EEA leak that required a reoperation. Minimally invasive approaches for anterior and middle fossa skull base meningiomas require careful case selection. GTR rates are equally high for all approaches except for spheno-orbital meningiomas, where alleviation of proptosis and not GTR is the primary goal of surgery. New anosmia was most common after EEA.

Exoscopic extradural anterior clinoidectomy.

Extradural anterior clinoidectomy is a resourceful technique to decompress the optic nerve as well as increase exposure of the parasellar region during extensive approaches. Despite requiring adjunctive epidural bone work, this technique allows safe optic nerve mobilization and early devascularization for anterior clinoidal meningioma resection. This 2D operative video describes right optic nerve decompression by extradural anterior clinoidectomy and subsequent resection of a right Al-Mefty type III clinoid meningioma under exoscope magnification. The patient was a 50-year-old woman with a 1-year history of right visual acuity impairment and papillary atrophy. The exoscope allows a 360° view around the anterior clinoid, improving maneuverability. The video can be found here: https://stream.cadmore.media/r10.3171/2023.10.FOCVID23118.

The factors influencing postoperative efficacy of anterior clinoidal meningioma treatment and an analysis of best-suited surgical strategies.

To explore the influence of the type of anterior clinoidal meningioma on surgical strategy planning, surgical approach selection, and postoperative efficacy. We conducted a retrospective analysis of the clinical data of 63 cases, including data on visual function, extent of tumor resection, and postoperative follow-up. Grade I and II approaches were selected according to the type of tumor. A univariate analysis of the factors influencing the extent of tumor resection, postoperative visual function, and postoperative relapse and complications was conducted. Simpson Grade I-II total resection was seen in 48 cases (76.2%), with an overall relapse/progression rate of 12.7%. The tumor type and texture and the relationship between the tumors and adjacent structures were the main factors influencing total tumor resection (P < 0.01). The overall postoperative visual acuity improvement, stabilization rate, and deterioration rate were 76.2, 15.9, and 7.9%, respectively. Postoperative visual acuity level was significantly correlated with preoperative visual acuity level and tumor type (P < 0.01). Determining the type of tumor at a preoperative level and whether the optic canal and cavernous sinus are invaded can aid in the planning of detailed individualized surgical strategies.

How I do it: a purely endoscopic endonasal approach for anterior clinoidal meningioma.

Surgery for anterior clinoid meningiomas (ACMs) remains challenging due to their tight adhesion to vital neurovascular and has been traditionally performed through a transcranial approach. We present the key steps of the endoscopic endonasal approach (EEA) for ACMs with a video illustration and figures. The relevant surgical anatomy is described along with the indications and limitations of this approach. The EEA offers a good treatment option for selected ACMs. It allows for the removal of involved hyperostotic bone and dural attachments, early identification and control of the neurovascular structure, and avoidance of brain retraction.

Extended endoscopic transorbital approach with superior-lateral orbital rim osteotomy: cadaveric feasibility study and clinical implications (SevEN-007).

The endoscopic transorbital approach (ETOA) has been developed, permitting a new surgical corridor. Due to the vertical limitation of the ETOA, some lesions of the anterior cranial fossa are difficult to access. The ETOA with superior-lateral orbital rim (SLOR) osteotomy can achieve surgical freedom of vertical as well as horizontal movement. The purpose of this study was to confirm the feasibility of the ETOA with SLOR osteotomy. Anatomical dissections were performed in 5 cadaveric heads with a neuroendoscope and neuronavigation system. ETOA with SLOR osteotomy was performed on one side of the head, and ETOA with lateral orbital rim (LOR) osteotomy was performed on the other side. After analysis of the results of the cadaveric study, the ETOA with SLOR osteotomy was applied in 6 clinical cases. The horizontal and vertical movement range through ETOA with SLOR osteotomy (43.8° ± 7.49° and 36.1° ± 3.32°, respectively) was improved over ETOA with LOR osteotomy (31.8° ± 5.49° and 23.3° ± 1.34°, respectively) (p < 0.01). Surgical freedom through ETOA with SLOR osteotomy (6025.1 ± 220.1 mm3) was increased relative to ETOA with LOR osteotomy (4191.3 ± 57.2 mm3) (p < 0.01); these values are expressed as the mean ± SD. Access levels of ETOA with SLOR osteotomy were comfortable, including anterior skull base lesion and superior orbital area. The view range of the endoscope for anterior skull base lesions was increased through ETOA with SLOR osteotomy. After SLOR osteotomy, the space for moving surgical instruments and the endoscope was widened. Anterior clinoidectomy could be achieved successfully using ETOA with SLOR osteotomy. The authors performed ETOA with SLOR osteotomy in 6 cases of brain tumor. In all 6 cases, complete removal of the tumor was successfully accomplished. In the 3 cases of anterior clinoidal meningioma, anterior clinoidectomy was performed easily and safely, and manipulation of the extended dural margin and origin dura mater was possible. There was no complication related to this approach. The authors evaluated the clinical feasibility of ETOA with SLOR osteotomy based on a cadaveric study. ETOA with SLOR osteotomy could be applied to more diverse disease groups that do not permit conventional ETOA or to cases in which surgical application is challenging. ETOA with SLOR osteotomy might serve as an opportunity to broaden the indication for the ETOA.

The Endoscopic-Assisted Supraorbital Approach for Resection of Anterior Skull Base Meningiomas: A Large Single-Center Retrospective Surgical Study.

Objective The endoscopic-assisted supraorbital approach (eSOA) constitutes a minimally invasive strategy for removing anterior skull base meningiomas (ASBM). We present the largest retrospective single-institution and long-term follow-up study of eSOA for ASBM resection, providing further insight regarding indication, surgical considerations, complications, and outcome. Methods We evaluated data of 176 patients operated on ASBM via the eSOA over 22 years. Results Sixty-five tuberculum sellae (TS), 36 anterior clinoid (AC), 28 olfactory groove (OG), 27 planum sphenoidale, 11 lesser sphenoid wing, seven optic sheath, and two lateral orbitary roof meningiomas were assessed. Median surgery duration was 3.35 ± 1.42 hours, being significantly longer for OG and AC meningiomas ( p <0.05). Complete resection was achieved in 91%. Complications included hyposmia (7.4%), supraorbital hypoesthesia (5.1%), cerebrospinal fluid fistula (5%), orbicularis oculi paresis (2.8%), visual disturbances (2.2%), meningitis (1.7%) and hematoma and wound infection (1.1%). One patient died due to intraoperative carotid injury, other due to pulmonary embolism. Median follow-up was 4.8 years with a tumor recurrence rate of 10.8%. Second surgery was chosen in 12 cases (10 via the previous SOA and two via pterional approach), whereas two patients received radiotherapy and in five patients a wait-and-see strategy was adopted. Conclusion The eSOA represents an effective option for ASBM resection, enabling high complete resection rates and long-term disease control. Neuroendoscopy is fundamental for improving tumor resection while reducing brain and optic nerve retraction. Potential limitations and prolonged surgical duration may arise from the small craniotomy and reduced maneuverability, especially for large or strongly adherent lesions.

Modified intradural anterior clinoidectomy to protect the paraclinoid neurovascular structures: A technical note

ObjectiveAnterior clinoidectomy is effective in creating an adequate working field during surgery for paraclinoid lesions. However, intradural anterior clinoidectomy (iAC) is associated with intraoperative injury to the paraclinoid neurovasular structures because they are exposed in the surgical field. Here we introduce our modified technique in removing the anterior clinoid process (ACP) to compensate the drawbacks of iAC. MethodsThis technical case report is presented by demonstration of cadaver dissection and surgical video. ResultsCadaver dissection study demonstrates the step-by-step procedure. Our technique primarily aims at sectioning of the dura adjacent to the ACP to obtain both intradural and extradural operative fields. With this technique, the ACP can be safely removed without injuring the neurovascular structure, such as the optic nerve and internal carotid artery. As an example of its clinical application, we present a case of a 67-year-old woman with anterior clinoid meningioma and visual deficits. The ACP was safely removed using a high-speed drill without injuring the neurovascular structures. Gross total resection was achieved. Her vision returned to normal postoperatively. ConclusionsUsing our modified technique, the widely reflected dura covers the critical neurovascular structure during the skull base drilling. Therefore, this technique compensates the drawbacks inherent to iAC.

Individualized Cerebral Artery Protection Strategies for the Surgical Treatment of Parasellar Meningiomas on the Basis of Preoperative Imaging.

ObjectiveParasellar meningiomas (PMs) represent a cohort of skull base tumors that are localized in the parasellar region. PMs tend to compress, encase, or even invade the cerebral arteries and their perforating branches. The surgical resection of PMs without damaging neurovascular structures is challenging. This study aimed to analyze functional outcomes in a series of patients who underwent surgery with individualized cerebral artery protection strategies based on preoperative imaging.MethodsA retrospective review was performed on a single surgeon’s experience of the microsurgical removal of PMs in 163 patients between January 2012 and March 2020. Individualized approaches with a bidirectional dissection strategy were used. Cerebral artery invasion classification, neurological outcomes, MRC Scale for muscle strength, and Karnofsky performance scale were used to assess tumor vascular invasion, functional outcome, and patient quality-of-life outcomes, respectively.ResultsTotal resection (Simpson grade I or II) was achieved in 114 patients (69.9%) in our study. A total of 44.7% of patients had improved vision at consecutive follow-ups, 51.1% were stable, and 3.8% deteriorated. Improvements in cranial nerves III, IV, and VI were observed in 41.1%, 36.2%, and 44.8% of patients, respectively. The mean follow-up time was (38.8 ± 27.9) months, and the KPS at the last follow-up was 89.6 ± 8.5. Recurrence was observed in eight patients (13.8%) with cavernous sinus meningiomas, and the recurrence rates in anterior clinoid meningiomas and medial sphenoid wing meningiomas were 3.8% and 2.8%, respectively.ConclusionsPreoperative imaging is important in the selection of surgical approaches. Maximum tumor resection and cerebral artery protection can be achieved concurrently by utilizing the bidirectional dissection technique. Individualized cerebral artery protection strategies provide great utility in improving a patient’s quality of life.

Complete Removal of Bilateral Clinoidal Meningiomas Through a Pterional Approach: 3-Dimensional Operative Video

Abstract Surgical removal of anterior clinoidal meningiomas remains a challenge because of its complicated relationship with surrounding vascular and neural structures. 1-3 This is a 39-yr-old female, with headaches, neurofibromatosis type 2, and history of 3 previous brain surgeries. The patient gave the consent to use the images and surgical video. In the imaging control, the growth of bilateral anterior clinoidal meningiomas was observed. A right pterional approach and extradural anterior clinoidectomy was performed, and a complete resection of bilateral clinoidal meningiomas was achieved obtaining a Simpson scale resection grade 1. The patient evolved without neurological deficits after the surgery, and the postoperative magnetic resonance imaging (MRI) evidenced a complete bilateral resection of the clinoidal meningiomas. Clinoidal meningiomas are the unique subset of tumors because of their close proximity to neurovascular structures and can be safely excised with minimal morbidity and mortality using microsurgical techniques. 3-5 In rare cases of bilateral anterior clinoidal meningiomas such as the case presented, we recommend detailed neuroimaging analysis and consider the possibility to resect both in a single approach.

Simpson Grade I Resection of Type II Clinoidal Meningioma Through Cranio-orbital Zygomatic Approach: 2-Dimensional Operative Video.

Clinoidal meningiomas have been considered as a separate entity with distinguishing clinical, radiological, and surgical considerations.1-2 Surgical mortality and morbidity associated with anterior clinoidal meningiomas has remained high in the past, with radical resection considered unattainable.3 However, the extent of surgical removal is clearly the most determining factor in tumor recurrence and progression. Clinoidal meningiomas have been classified into 3 types according to their origin from the dura surface of the anterior clinoid and subsequent arachnoidal rearrangement around the parasellar neurovascular structures.1 In type II, there is an arachnoidal plane that allows the tumor dissection from the encased carotid artery and its branches and the optic nerve. In this type, the involvement of the cavernous sinus is limited to the external wall, which can also be removed. Hence, these tumors are amenable to Simpson grade I resection (tumor, dura, and bone). Approaching through the multidirectional axis provided by the cranio-orbital zygomatic approach allows safe exposure of the tumor and vascular control.4-5 Proximal carotid control is obtained in the petrous carotid canal, the invaded anterior clinoid is removed by and large extradurally, and the Sylvian fissure is split wide open to establish dissecting planes with the middle cerebral artery branches. The optic canal is opened, and tumor extension is removed.6 The invaded outer wall of the cavernous sinus and superior orbital fissure is removed. We demonstrate this technique in a 48-yr-old patient who consented for surgery and publication of images. All images at 2:27, center and right images at 2:46, and all images at 2:58, reused with permission from LWW, from Al-Mefty, Operative Atlas of Meningiomas. Left image at 2:46 reprinted from Surg Neurol, Vol 60/issue 6, Arnautović KI, Al-Mefty O, Angtuaco E, A combined microsurgical skull-base and endovascular approach to giant and large paraclinoid aneurysms, pp. 504-520, Copyright 1998, with permission from Elsevier. Image at 8:21 reprinted from Al-Mefty,1 Clinoidal meningiomas, by permission from JNSPG.

A-158 Case Study: Cognitive Deficits Associated with Postoperative Intracranial Hemorrhage Following Meningioma Resection

Abstract Objective Postoperative intracranial hemorrhages (PIH) are an infrequent complication following cranial tumor resection and associated with prolonged hospitalization as well as long-term neurologic deficits. There is limited research examining the neuropsychological deficits resulting from PIH following meningioma resection, especially with neuropsychological data. Here, we present the neurocognitive profile of a patient who underwent a meningioma resection surgery and subsequently suffered a PIH within the resection cavity. Method Mr. Doe is a bilingual male in his late 40s who developed right-side vision loss and an isolated incidence of disorientation, resulting in discovery of a left anterior clinoid meningioma. He underwent a left frontotemporal craniotomy for gross total resection of the mass a month after discovery. Postoperative neuroimaging the following day revealed the appearance of a hematoma and intracranial hemorrhage within the resection cavity, resulting in right hemiplegia, aphasia, and ophthalmoplegia. He underwent neuropsychological evaluation 15 months post-resection, to assess residual cognitive deficits following his hospitalization and subsequent inpatient rehabilitation. Results In the context of average premorbid intellectual functioning, Mr. Doe’s neurocognitive profile was notable for deficits in processing speed, receptive and expressive language, and executive functioning associated with speed/verbally mediated tasks. Testing revealed lateralized deficits indicative of left (language-dominant) hemisphere dysfunction secondary to meningioma resection and subsequent PIH within the resection cavity. Conclusion The current poster aims to contribute to the limited body of literature examining residual neuropsychological deficits resulting from PIH following intracranial resection of meningioma. This is especially crucial given that long-term cognitive deficits can negatively impact patients’ quality of life over time.

Extradural anterior clinoidectomy in surgical management of clinoidal meningiomas

BackgroundDespite the recent advances in skull base surgery, microsurgical techniques, and neuroimaging, yet surgical resection of clinoidal meningiomas is still a major challenge. In this study, we present our institution experience in the surgical treatment of anterior clinoidal meningiomas highlighting the role of extradural anterior clinoidectomy in improving the visual outcome and the extent of tumor resection. This is a prospective observational study conducted on 33 consecutive patients with clinoidal meningiomas. The surgical approach utilized consisted of extradural anterior clinoidectomy, optic canal deroofing with falciform ligament opening in all patients. The primary outcome assessment was visual improvement and secondary outcomes were extent of tumor resection, recurrence, and postoperative complications.ResultsThe study included 5 males and 28 females with mean age 49.48 ± 11.41 years. Preoperative visual deficit was present in 30 (90.9%) patients. Optic canal involvement was present in 24 (72.7%) patients, ICA encasement was in 16 (48.5%), and cavernous sinus invasion in 8 (24.2%). Vision improved in 21 patients (70%), while 6 patients (20%) had stationary course and 1 patient (3%) suffered postoperative new visual deterioration. Gross total resection was achieved in 24 patients (72.7%). The main factors precluding total removal were cavernous sinus involvement and ICA encasement. Mortality rate was 6.1%; mean follow-up period was 27 ± 13 months.ConclusionsIn this series, the use of extradural anterior clinoidectomy provided a favorable visual outcome and improved the extent of resection in clinoidal meningioma patients.

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

Clinoidal Meningioma with Cavernous Sinus Invasion.

We present a-49-year old female presenting headache and progressive right eye visual loss in the last 6 months. Magnetic resonance imaging showed a large clinoidal meningioma on the right side, invading the superior, lateral and medial aspects of the cavernous sinus, the optic canal, and the clinoidal segment of the internal carotid artery (ICA).A cranio-orbital approach was performed. The anterior clinoid process was removed extradurally to achieve devascularization of the anterior clinoidal meningioma, followed by the peeling of the middle fossa to decompress V2 and open the superior orbital fissure. We open the dura in a standard fronto-temporal flap to access the lower portion of the skull base allowing retractorless dissection. We complete the removal of the anterior clinoid process and optic strut through an intradural approach. It allows safer dissection of the clinoidal segment of the ICA and avoids its injury by adherent and hard consistency tumor.Intraoperative neurophysiological monitoring, sharp dissection, and avoiding the use of bipolar coagulation when dissecting the cavernous sinus are essential to minimize the risk of cranial nerve injury. We also like to point that cranial nerve deficit caused by surgical manipulation without primary lesion of the nerve can be recovered postoperatively. The link to the video can be found at: https://youtu.be/ozUCsnUGxyM .

Tailored Optic Unroofing for Type III Clinoidal Meningioma: Description of a Surgical Technique

Background: Anterior clinoidal meningiomas are heterogeneous types of lesions that comprise the parasellar lesions group. Due to their close relationship with the optic nerve and internal carotid artery, they become challenging pathologies for neurosurgeons. Case Description: Female 47, presented with superior temporal quadrantanopsia on the right side. Magnetic resonance image revealed type III clinoidal meningioma on the right side. She has undergone a pterional craniotomy for an optic canal unroofing and tumor extraction. Two years of postoperative follow-up the patient underwent a campimetry, which revealed an almost complete visual improvement. Conclusion: To date, the best surgical technique has not yet been defined, so the choice of treatment and surgical technique is based on each case and on the surgeons’ experience.