Falcotentorial Meningiomas Research Articles

Temporary Visual Hallucinations in a 31-year-old Female Patient Post Falcotentorial Meningioma Resection with No History of Psychosis: A Case Report

Introduction: Falcotentorial meningiomas are rare, comprising 1%–2% of all intracranial meningiomas, arising at the junction of the falx cerebri and tentorium. These tumors may compress the quadrigeminal plate and/or splenium, leading to peduncular hallucinosis—vivid, colorful visual hallucinations of people and animals, which can persist even after tumor removal. Case Description: A 31-year-old woman with no psychosis history presented with a bilateral visual field deficit and left extremity weakness. Brain MR imaging revealed a lobulated mass attached to the right cerebellar tentorium, posterior falx cerebri, and adjacent venous sinuses. Visual field analysis showed homonym superior quadranopsia. Following craniotomy and tumor removal, histology confirmed a mixed-type meningioma. Post-surgery, the patient experienced vivid visual hallucinations that resolved in two weeks, but bilateral visual field deficits remained. A post-op CT showed reduced structural compression around the lesion with slight narrowing of the quadrigeminal cistern. Discussion : Visual hallucinations in falcotentorial meningioma patients, often as peduncular hallucinosis, occur due to compression of the quadrigeminal plate and/or splenium and may persist post-surgery if lesions are present in the cerebral peduncles or nearby midbrain areas. Conclusion: The patient's temporary hallucinations may have resulted from post-resection tissue edema causing quadrigeminal cistern narrowing or indicate lesions in the cerebral peduncles or adjacent midbrain regions.

Falcotentorial Meningiomas: Insights from Surgical Strategies and Clinical Outcomes.

Background: Falcotentorial meningiomas are exceptionally uncommon tumors, presenting a challenge for neurosurgeons due to their close proximity to vital structures. Gross total resection represents the standard of treatment for these tumors. However, care must be taken when surgically approaching these lesions, since damaging neurovascular structures may cause unacceptable morbidity. Selecting the optimal surgical approach for each tumor is of paramount importance when treating these patients. Methods: The authors reviewed medical records to identify all patients with falcotentorial meningiomas who underwent resection at the University Hospital of Freiburg between January 2001 and December 2021. Clinical and imaging data, surgical management, and clinical outcomes were analyzed. Results: Falcotentorial meningiomas occurred in 0.7% (15 of 2124 patients) of patients with intracranial meningiomas. Of these 15 patients, 8 were female and 7 male. The occipital interhemispheric approach was used in nine patients, the supracerebellar infratentorial approach in five patients, and the retrosigmoidal approach in one patient. Three patients developed visual field deficits after surgical resection. Incomplete resection was significantly associated with tumor progression (p < 0.05). Conclusions: Individualized surgical strategies, guided by preoperative imaging and classification systems, play a crucial role in optimizing patient care. Among the available approaches, the occipital interhemispheric and supracerebellar infratentorial approaches are frequently employed and considered among the safest options for these tumors.

SURG-30. CLINICAL CONSIDERATIONS, APPROACH SELECTION, AND OUTCOMES ASSOCIATED WITH TREATMENT STRATEGIES FOR FALCOTENTORIAL MENINGIOMAS: SYSTEMATIC REVIEW AND META-ANALYSIS OF THE CURRENT EVIDENCE

Abstract INTRODUCTION Meningiomas at the falcotentorial (FT) junction are rare, as they account for only 0.3%-1.1% of all intracranial meningiomas. Clinical management of FT meningiomas can be challenging. METHODS The authors queried three databases per PRISMA guidelines to identify all studies reporting indications for surgical resection of FT meningioma. RESULTS Thirty studies reporting 224 FT patients met pre-specified inclusion criteria. Patients diagnosed with FT meningioma demonstrated a predilection for headache on initial examination (p = 0.030).Headache was the mostly commonly reported symptom, present more often than visual disturbance (RR 2.28 [1.59, 3.26], I2=0%, P &amp;lt; 0.00001), ataxia or imbalance (RR 0.21 [0.08, 0.35], I2= 0%, P = 0.002), and cognitive disturbance (RR 0.34 [0.20, 0.47], I2 = 12%, P &amp;lt; 0.00001). An overwhelming majority of lesions (n = 97, 80.2%) were benign, WHO Grade I. The primary arterial feeders supplying the FT lesions were reported in 13 studies; most commonly, these arterial feeders included the distal branches of the ICA (n = 29), ECA (n = 25), and vertebrobasilar vasculature (n = 35). Visual deficits (n = 32, 14.3%) were the most common postoperative complication.Bassiouni classification of the tumors was reported in 10 studies, with 27 (31.8%) classified as type I, 16 (18.8%) as type II, 37 (43.5%) as type III, and five (5.9%) as type IV FT meningiomas.Simpson Grade I resection (n = 76, 43.7%) was achieved in slightly less than half of cases. Cases involving multi-stage resections appeared to confer greater risk (RR 1.42 [0.72, 2.80], I2=0%, P = 0.31) for STR (failure to achieve GTR or Simpson Grade I resection). CONCLUSION The primary objective when treating FT meningiomas is to achieve gross total resection (GTR) or Simpson Grade 1 resection. Grade 2 resection is also regarded as a good outcome for these lesions. This goal should be pursued while minimizing cerebellar retraction and protecting vital vascular structures, such as the Galenic venous system.

Role of imaging in falcotentorial meningiomas: a case report

BackgroundFalcotentorial meningiomas are rare tumors that arise from the junction of the falx cerebri and the tentorium. Accurate preoperative imaging plays a crucial role in surgical planning and management. Magnetic resonance imaging (MRI) is the preferred imaging modality for meningiomas. In this report, we present a case of type 1 falcotentorial meningioma and discuss the role of preoperative imaging and management.Case presentationA 62-year-old female patient presented with gradually progressive bilateral lower limb weakness. Contrast-enhanced MRI showed a circumscribed lobulated extraaxial lesion near the falcotentorial junction with an adjacent dural tail, consistent with a type 1 falcotentorial meningioma. Based on these radiological features, the patient was diagnosed with a type 1 falcotentorial meningioma. The patient was referred for neurosurgical evaluation for further management.ConclusionFalcotentorial meningiomas are rare tumors that require careful preoperative imaging and surgical planning. Radiological reporting should include the relationship of the tumor to the vein of Galen to aid neurosurgical approach. Complete surgical resection is the preferred therapy, but subtotal resection can be considered in certain cases.

The parietooccipital interhemispheric transtentorial approach for pineal tumors

Access to the pineal region has always been a challenge for neurosurgeons. The parietooccipital interhemispheric transtentorial approach is a slight variation of the traditional occipital transtentorial approach that provides adequate exposure to the lesions of the pineal region without introducing additional risks. In this study, the modified parietooccipital interhemispheric transtentorial approach is discussed including step-by-step anatomical cadaveric dissections and operative images. 27 adult patients (age > 18) who were operated over a 30-year period (1992–2022) by the senior author (M.N.P.) at two clinics, Marmara University, Department of Neurosurgery, Istanbul, Turkey and Acibadem Mehmet Ali Aydinlar University, Department of Neurosurgery, Istanbul, Turkey were analyzed. Only pineal region tumors were included in the analysis. Falcotentorial meningiomas and vascular lesions including cavernomas were excluded. 5 cadaveric specimens were dissected step by step following the surgical approach. Each step was documented using a Canon EOS 5D Mark II camera with Canon 100 mm Macro Lens. Step by step images of the dissections were presented including comparison with surgical images. Additional illustrations were used to describe the surgical corridor. The surgical corridor is maintained anterior to the parietooccipital sulcus along the medial of the precuneus. No retraction to the calcarine sulcus resulted in no postoperative hemianopsia. The neurovascular structures along the surgical corridor along with the nuances of the tentorium incision and splenium resection are discussed. The parietooccipital interhemispheric transtentorial approach provides a wide and safe corridor for surgical resection of pineal tumors.

Falcotentoral meningiomas: Optimal surgical planning and intraoperative challenges - case report

IntroductionFalcotentorial meningiomas (FTM) are a rare entity of tumors, corresponding to 2-8% of pineal tumors and 1% of all intracranial meningiomas and are more prevalente in womens. These tumors originate from posterior portion of the velum interpositum or falcotentorial union and can present different relationships with vital neuroanatomical structures. The surgical treatment is not well established in literature, due to the necessity of validating criteria for the surgical approach and the discussion of the risks to obtain radical resections.Case descriptionIt is a case report of a 41-year-old man with FTM, who was admitted with progressive paresis in the left lower limb for the last one year as the only neurological symptom. A computed tomography (CT) was realized, revealing a solid mass in the pineal region, causing hydrocephalus. After that, brain magnetic resonance imaging (MRI) showed a solid mass inside the third ventricule in contact with the falcotentorial dural junction. The patient was submited of a subtotal tumor resection by an approach throught occipito-transtentorial acess.CommentsThe clinic of the FTMs varies with headaches (the most common symptom), ataxia, personality changes and bradpsychia with homonymous hemianopsia. There exists four types of FMTs tumors according to Boussioni classification, which is based on the location of the tumor and, in this case, the tumor is type I, which originated from posterior cerebral falx and displaced the venous system inferiorly. This classification it’s important to guide the decision of the surgical approach. The surgical objective is to relieve or solve neurological/clinical symptoms and acquire a tissue sample for histological diagnosis. Some surgical approaches can be done for these tumors, but the transtentorial/transfalcine occipital approach is most frequently used for pineal meningiomas, especially in types I and IV FTMs.ConclusionThe choice of the surgical approach is essential for the effective treatment of a FTM tumor, and can be analysed with the help of imaging tests. This case of a subtotal resection showed success on the reduce of neurological defict of the patient. Keywords: Falcotentorial meningiomas, Surgical approach, Neurosurgery.

Multi-staged approach for safe removal of tentorial meningioma – A case report

Falcotentorial meningiomas are rare and comprise only 0.3-1.1% of all meningiomas. The choice of surgical strategy for such lesions is not straightforward. 46 year old female came to our institute with complaints of gradually intensifying headache since 3 months which had aggravated over a period of 5 days. MRI Brain with contrast was done which showed a large, well circumscribed, lobulated, midline, extra-axial lesion attached to the posterior third of the falx and the anterior lip of the tentorium. The surgical plan was to excise the infra tentorial portion, for which a Steins (supra cerebellar infra tentorial) approach was deployed. Attempts to approach the supratentorial portion by incising the tentorium were unsuccessful as the required trajectory was far too acute. The supra tentorial portion would have to be approached by a more cranial trajectory, and hence it was decided to tackle that portion at a second stage. Some tumors may not be amenable to total excision in a single sitting. This case is being reported to underline the importance of a delayed 2 stage approach to excise this complex genre of Falcotentorial meningiomas which invade the supra and infra tentorial compartments.

Occipito-transtentorial approach for falcotentorial meningiomas: how I do it

BackgroundFalcotentorial meningiomas are rare tumors that arise at the junction of the dural folds of the tentorium and falx cerebri, at the junction of the vein of Galen with the straight sinus with possible extensions along the course of the straight sinus. Surgery of falcotentorial meningiomas remains challenging due to the intimate neurovascular relationships in the posterior incisural space.MethodsWe describe the key steps of the occipito-transtentorial approach for falcotentorial meningiomas with a video illustration. The surgical anatomy is described along with the advantages and limitations of this approach.ConclusionThe occipito-transtentorial approach offers good surgical exposure and outcomes in carefully selected patients harboring falcotentorial meningiomas. Precise understanding of the relationship between the tumor and the internal cerebral veins, basal veins, and vein of Galen should be thoroughly analyzed as these structures may be infiltrated or displaced.

Two-stage endoscopic assisted approach for large pineal region and falcotentorial meningioma: first stage paramedian supracerebellar infratentorial approach, second stage interhemispheric occipital transtentorial approach: surgical cases and anatomical study.

Resection of complex falcotentorial meningiomas, growing along the pineal region (PR), and posterior incisural space (PIS) represents a neurosurgical challenge. Here, we present our strategy for effective resection of large falcotentorial meningiomas applying a paramedian supracerebellar infratentorial and interhemispheric occipital transtentorial approach in staged surgeries. We further systematically compared the effectiveness of midline (MSIA) and paramedian (PSIA) supracerebellar infratentorial, as well as interhemispheric occipital transtentorial approaches (IOTA) to operate along the PR and PIS in 8 cadaveric specimens. The staged PSIA and IOTA enabled successful resection of both falcotentorial meningiomas with an uneventful postoperative course. In our anatomo-morphometrical study, superficial vermian veins at an average depth of 11.38 ± 1.5mm and the superior vermian vein (SVV) at 54.13 ± 4.12mm limited the access to the PIS during MSIA. MSIA required sacrifice of these veins and retraction of the vermian culmen of 20.88 ± 2.03mm to obtain comparable operability indexes to PSIA and IOTA. Cerebellar and occipital lobe retraction averaged 14.31 ± 1.014mm and 14.81 ± 1.17mm during PSIA and IOTA respectively, which was significantly lower than during MSIA (p < 0.001). Only few minuscule veins were encountered along the access through PSIA and IOTA. The application of PSIA provided high operability scores around the pineal gland, ipsilateral colliculus and splenium, and acceptable scores on contralateral structures. The main advantage of IOTA was improving surgical maneuvers along the ipsilateral splenium. In summary, IOTA and PSIA may be advantageous in terms of brain retraction, vein sacrifice, and operability along the PR and PIS and can be effective for resection of complex falcotentorial meningiomas.

Falcotentorial meningiomas: Optimal surgical planning and intraoperative challenges – case report

Meningiomas arising from the falcotentorial junction are rare, and the selection of the optimal surgical approach is essential. We report a 41-year-old man presented with progressive left paresis in the lower limbs. An MRI showed a solid mass inside the third ventricle in contact with the falcotentorial dural junction. The tumor was removed by the transtentorial/transfalcine occipital approach, performed with the patient in the three-quarter prone position. The tumor was devascularized from the tentorium, then debulked and finally dissected. The affected falx and tentorium were resected, but all of patent dural venous sinuses were preserved. The tumor was a subtotal resect. Choosing the surgical approach is essential for the safe and effective removal of an FTM and preoperative imaging analysis should identify the tumor’s anatomical relations and guide toward the least disruptive route that preserves the neurovascular structures. This article aims to report a successfully treated FTM.

Interhemispheric Precuneus Retrosplenial Transfalcine Approach for Falcotentorial Meningiomas: Anatomic Study and Clinical Series

Falcotentorial meningiomas are surgically challenging. Currently accepted approaches include occipital interhemispheric and supracerebellar infratentorial approaches, which have documented drawbacks. To propose an alternative approach to the posterior tentorial incisural space, the interhemispheric precuneus retrosplenial transfalcine approach (IPRTA). A total of 6 colored-silicone-injected adult cadaveric heads were dissected. We measured the interval between bridging veins and studied computed tomography venography scans of 20 subjects to confirm the feasibility of the IPRTA. Bony landmarks, the region's bridging veins, and the anterior and posterior borders of the approach were identified. The surgical corridor widths (veins' interval) and lengths were compared between alternative midline approaches. We also reviewed 4 consecutive clinical cases using this approach. The IPRTA provides the shortest distance to the anterior and posterior limits of the posterior tentorial incisura. Moreover, it is the only approach that provides direct visualization of the anterior and posterior limits of falcotentorial junction meningiomas. In all specimens and patients, a minimum 30-mm interval between the anterior and posterior parietal veins was found in at least one of the hemispheres. Tumor removal was successful in all 4 patients but resulted in mild paresthesia in the lower extremities of 2 patients and temporary foot drop in 1 patient. The IPRTA offers the shortest and most direct corridor for falcotentorial meningiomas and provides excellent visualization of most of the critical structures in the region. Detailed preoperative evaluation of the deep and superficial venous structures is recommended.

Posterior interhemispheric occipital transtentorial approach for resection of a falcotentorial meningioma.

Falcotentorial meningiomas arise along the junction of the falx cerebri and the tentorium cerebelli. The authors present a woman in her 60s with an incidentally discovered falcotentorial meningioma, approximately 3 cm in diameter, resected with a torcular craniotomy and posterior interhemispheric approach. The galenic complex was dissected away from the tumor. In the final view, the bilateral internal cerebral veins and basal veins of Rosenthal were seen. A Simpson grade I resection was achieved. The patient experienced transient contralateral hemianopsia and was discharged home. At 1-year follow-up, her neurological examination findings were unremarkable, and there was no radiographic evidence of tumor.The video can be found here: https://stream.cadmore.media/r10.3171/2021.4.FOCVID2125.

Reinvestigation of the origins of pineal meningiomas based on its related veins and arachnoid membranes

BackgroundA series of patients harboring pineal region meningiomas were respectively analyzed to explore the origin of these tumors and the true meaning of the term “velum interpositum (VI) meningiomas”.Methods21 patients with pineal meningiomas underwent operation in Nanfang Hospital of Southern Medical University from January 2005 to December 2016 were retrospectively included to analyze the clinical features, imaging findings and surgical video data of these patients. According to the method of literature, the data of this group were also divided into falcotentorial (FT) meningiomas and VI meningiomas, and the differences between the two types of tumors were compared.ResultsAmong the 21 cases of tumor, there were 12 cases of FT meningiomas, including 4 cases originating from cerebral falx, 4 cases from tentorium of cerebellum and 4 cases from straight sinus; there were 9 cases of VI meningiomas, 7 of which originated from the arachnoid sleeve of the Galen vein, 1 from the posterior part of the internal cerebral vein and 1 from the posterior surface of the pineal gland. Postoperative pathological examination showed meningiomas in all the 21 patients, including 16 cases of total resection and 5 cases of subtotal resection. Postoperatively limitation of binocular vertical motion was found in 3 cases, homotropic hemianopia in 7 cases, hemiplegia in 1 case and death in 1 case.ConclusionsThis study suggests that pineal meningiomas are more suitable to be described by FT meningioma and meningiomas of the arachnoid of the pineal region by analyzing the origin of tumors. The term “VI meningiomas” can only reflect a part of meningiomas of the arachnoid of the pineal region. Before the removal of pineal meningiomas, more attention should be paid to the effects of the two types of tumors on the Galen vein and the straight sinus, and the establishment of venous collateral circulation.

Chapter 11 - Falcotentorial meningiomas

Falcotentorial meningiomas are uncommon tumors that account for 1%-2% of all intracranial meningiomas. They arise at the junction of the falx cerebri and tentorium, from the entry of the vein of Galen posteriorly to the confluence of venous sinuses. Treatment for these tumors depends on patient and tumor factors. Tumor factors include size of the tumor, patency of the straight sinus, and the amount of tumor above and/or below the tentorium. This chapter reviews the clinical presentation, imaging features, treatment options, and results.

Surgical treatment of falcotentorial meningiomas: a retrospective review of a single-institution experience.

Meningiomas at the falcotentorial junction represent a rare subgroup of complex meningiomas. Debate remains regarding the appropriate treatment strategy for and optimal surgical approach to these tumors, and surgical outcomes have not been well described in the literature. The authors reviewed their single-institution experience in the management, approach selection, and outcomes for patients with falcotentorial meningiomas. From the medical records, the authors identified all patients with falcotentorial meningiomas treated with resection at the Barrow Neurological Institute between January 2007 and October 2017. Perioperative clinical, surgical, and radiographic data were retrospectively collected. For patients who underwent the supracerebellar infratentorial approach, the tentorial angle was defined as the angle between the line joining the nasion with the tuberculum sellae and the tentorium in the midsagittal plane. Falcotentorial meningiomas occurred in 0.97% (14/1441) of the patients with meningiomas. Most of the patients (13/14) were female, and the mean patient age was 59.8 ± 11.3 years. Of 17 total surgeries (20 procedures), 11 were single-stage primary surgeries, 3 were two-stage primary surgeries (6 procedures), 2 were reoperations for recurrence, and 1 was a reoperation after surgery had been aborted because of brain edema. Hydrocephalus was present in 5 of 17 cases, 4 of which required additional treatment. Various approaches were used, including the supracerebellar infratentorial (4/17), occipital transtentorial/transfalcine (4/17), anterior interhemispheric transsplenial (3/17), parietal transventricular (1/17), torcular (2/17), and staged supracerebellar infratentorial and occipital transtentorial/transfalcine (3/17) approaches. Of the 17 surgeries, 9 resulted in Simpson grade IV resection, and 3, 1, and 4 surgeries resulted in Simpson grades III, II, and I resection, respectively. The tentorial angle in cases with Simpson grade I resection was significantly smaller than in those with an unfavorable resection grade (43.3° ± 4.67° vs 54.0° ± 3.67°, p = 0.04). Complications occurred in 10 of 22 approaches (17 surgeries) and included visual field defects (6 cases, 2 permanent and 4 transient), hemiparesis (2 cases), hemidysesthesia (1 case), and cerebellar hematoma (1 case). Falcotentorial meningiomas are challenging lesions. A steep tentorial angle is an unfavorable preoperative radiographic factor for achieving maximal resection with the supracerebellar infratentorial approach. Collectively, the study findings show that versatility is required to treat patients with falcotentorial meningiomas and that treatment goals and surgical approach must be individualized to obtain optimal surgical results.

Unedited microneurosurgery of a falcotentorial meningioma

Background:Falcotentorial meningiomas are pineal region meningiomas that arise from the dura of the tentorium cerebelli and posterior part of the falx. These tumors are commonly supplied by branches of the internal carotid artery such as the meningohypophyseal trunk, inferolateral trunk, and anterior choroidal artery. Less frequently, branches of the ophthalmic artery, vertebral artery, or external carotid artery are also involved. Based on neuroimaging studies, falcotentorial meningiomas may be classified as anterior, superior, inferior, and posterior types. Here, we present an unedited microsurgical resection of a superior falcotentorial meningioma.Case Description:The patient with a meningioma of the posterior inferior falx and a minimal extension to the tentorium underwent sitting praying position and a right occipital interhemispheric approach. Strong retraction of the dura followed a superior sagittal sinus based opening. Careful microsurgical access between the medial surface of the occipital lobe and the falx toward the splenium of corpus callosum allowed us to recognize the lesion. Thus, a cottonoid placed over the cerebral surface avoiding direct contact with the bipolar forceps, and the constant separation of the falx cerebri with the aspiration tube along the access developed a proper surgical route preventing any cortical lesion. Along the approach, cerebrospinal fluid was continuously released from the pericallosal cistern as well. Once well recognized the meningioma, we proceeded with the internal decompression of the lesion using a thumb regulated suction tube and bipolar forceps. Tissue samples from the tumor were taken for the histological diagnosis, and under conventional microsurgical technique, the meningioma was completely removed by piecemeal technique. A small lateral tear on the falx required hemostatic reparation with Tachosil. Water dissection provided us a clear cleavage plane for the microsurgical dissection of the tumor and maintained a clean operative field along the procedure. Occipital arteries running over the lateral surface of the meningioma were carefully dissected and isolated from the lesion, while the deep venous system did not achieve any contact with the tumor. After the ipsilateral component of the meningioma was resected, we intent are dissecting the contralateral segments of the tumor with a curved dissector. At the last stage of the surgery, small incision at a tumor-free segment of the falx allowed us to remove the falcotentorial attachment of the lesion. Under high microscopic magnification, the remaining minimal portion of meningioma extending under the tentorium was coagulated. After complete microsurgical removal of the meningioma, careful homeostasis based on electrocoagulation surgical and Tachosil was achieved. Finally, we performed a surgical wound closure under standard technique.Conclusion:This unedited video offers all detailed aspects for an efficient and safe falcotentorial meningioma microneurosurgery.Videolink:http://surgicalneurologyint.com/videogallery/pineal-meningioma.

Meningiomas Originated at the Falcotentorial Region: Analysis of Topographic and Diagnostic Features Guiding an Optimal Surgical Planning

Meningiomas arising at the pineal region are a rare entity and still represent a great neurosurgical challenge given their deep location and critical neuroanatomic relationships. The optimal surgical approach to treat these lesions is still under debate. Our objective is to review the topographic and diagnostic features of these lesions, which can help to guide an optimal surgical outcome. We present 2 clinical cases of falcotentorial meningiomas successfully treated at our institution (2016-2017) with different surgical approaches. A literature review is performed, and a description of the classification, anatomic relationships, clinical features, diagnosis, and different surgical options and outcomes of these lesions is presented. The first patient was treated via a supracerebellar infratentorial approach, and the second patient was treated via a parieto-occipital interhemispheric approach. In both tumors, a gross total resection was achieved with no permanent neurologic deficits. In the literature review, gross total resection rates range from 33% to 100%, with no differences regarding the type of meningioma or the surgical approach performed. Permanent neurologic morbidity varies from 0% to 50%, and mortality rates range from 0% to 23%. The distortion and displacement of the vein of Galen and straight sinus represent the most important feature in the decision of optimal surgical approach. Pineal region meningiomas represent very infrequent, challenging lesions, and their description in the literature is scarce. The systematic topographic classification of these tumors and evaluation of the neuroanatomic structures involved are crucial to guide a safe and optimal surgical approach and achieve satisfactory outcomes.

Rethinking origins of pineal meningiomas

Objective To investigate the clinical data and origin of pineal meningiomas, and to discuss the definite meaning of the term interpositum . Methods From January 2005 to December 2016, 21 cases of pineal region meningiomas underwent operations at Department of Neurosurgery, Nanfang Hospital, Southern Medical University and were enrolled into this retrospective study. Analysis was conducted on the clinical characteristics, imaging findings and surgical video data of those patients who were divided into 2 groups according to literature: falcotentorial meningioma group and velum interpositum meningioma group. Comparison was conducted between the 2 groups. Results Among 12 cases of falcotentorial meningiomas, 4 cases were originated from cerebral falx, 4 from cerebellar tentorium and 4 from straight sinus. Among 9 cases of velum interpositum meningiomas, 7 were originated from the cerebral arachnoidal envelope, 1 from the posterior cerebral vein and 1 from pineal surface. Postoperative pathological examination confirmed the diagnosis of meningioma in all cases. Among those, total resection was achieved in 16 cases and subtotal resection in 5. There were 3 cases of vertical movement limitation of the eyes, 7 cases of isotropic hemianopia, 1 case of hemiplegia, and 1 case of death. Conclusions The falcotentorial meningioma and primary pineal meningioma might be more appropriate for classification of origins of pineal meningiomas. The term interpositum may not be able to accurately reflect the origin of meningioma in the pineal gland region. During resection of pineal gland meningiomas, the protection of large veins and collateral circulation is of much significance. Key words: Meningioma; Pinealoma; Classification; Neurosurgical procedures

Surgical Management of Medial Tentorial Meningioma: Falcotentorial and Torcular

Falcotentorial meningiomas (FTM) stand out for their rarity, inconsistent definition, and surgical complexity. It is appropriate to deal with them in the context of medial tentorial meningiomas (TMs). Clinical and radiologic characteristics of medial TMs, comprising the typical features of FTM and TM, along with surgical management and short-term and long-term outcomes, are reported. FTM (n= 16) were typically supratentorial, large, edematous tumors that caused mainly headache and hemianopia; TM (n= 12) were infratentorial, smaller not edematous tumors that caused mainly headache and gait ataxia. The most frequent venous pattern was straight sinus infiltration in one third of cases of FTM and occlusion in one half of cases of TM. Total removal (Simpson grade I-II) was obtained in 46.4% of cases and subtotal removal (Simpson grade III-IV) in 53.6%. Suprainfratentorial extension in FTM and incomplete venous invasion in TM were the factors most likely opposing complete removal. The overall acute complications rate was 32.1% (higher for FTM), transient for most cases. Patients with supratentorial meningiomas performed significantly worse preoperatively (Karnofsky Performance Status ≤70 in 75% of cases); patients with infratentorial symptoms/signs recovered worse postoperatively. Stereotactic radiosurgery with subtotal removal was used as adjuvant treatment in 8 cases. Only 2 recurrences, both atypical tumors, occurred at 57.6 months (mean) follow-up. As a general rule, careful venous management, tailored surgical approach for FTM, and cautious tumor removal for TM can yield good and stable results. Total removal accounts for half the cases in both groups, whereas FTM was associated with worse postoperative complications.

Surgical Treatment for Falcotentorial Meningiomas.

Among intracranial meningiomas, falcotentorial meningiomas, occurring at the junction of the falx cerebri and tentorial dural folds, are extremely rare. Because of their deep location, they are surrounded by critical structures, and have been regarded as one of the most challenging lesions for surgical treatment. In this study, we describe our surgical strategy for falcotentorial meningiomas and provide a review of our experience.