Is Falcine Meningioma a Diffuse Disease of the Falx? Case Series and Analysis of a "Grade Zero" Resection

Time to Recurrence of Intracranial Meningiomas from a Monoinstitutional Surgical Series

BACKGROUND

Meningiomas show variable tendency to recur. While risk factors of recurrence have been largely investigated in literature, a paucity of data is available on the time to recurrence. Our purpose was to identify main factors affecting the time to recurrence to assist preoperative treatment decision-making strategy and to define a tailored clinical and neuroradiological follow-up.

METHODS

Data of 35 patients with intracranial meningioma recurrences have been retrospectively reviewed. Demographic (patient age at initial diagnosis and sex), radiologic (meningioma location, pattern of regrowth and topography of recurrences at first reoperation), pathologic (WHO grade and Ki67-MIB1 at initial surgery and at first reoperation, progesterone receptor [PR] expression), and surgical (extent of resection at initial surgery according to Simpsons grading system, number of reoperations) factors were analyzed.

RESULTS

Time to recurrence ranged from 20 to 120 months. Extent of resection at initial surgery was Simpson grade I in 7 patients (20%), grade II in 10 (28.5%), grade III in 14 (40%), and grade IV in 4 (11.5%). Longer median time to recurrence was observed for skull base localization (P < 0.01), Simpson grades I and II versus grades III (P = 0.01) and IV (P = 0.02), values of Ki67-MIB1 ≤ 4% (P = 0.001), and PR > 60% (P = 0.03); conversely, sex, age, number of reoperations, unchanged/progression of Ki67, and/or World Health Organization grade between first surgery and reoperation did not correlate in statistically significant way with time to recurrence.

CONCLUSIONS

The extent of resection and the Ki67-MIB1 represent the most important factors predicting shorter recurrence time of intracranial meningiomas. Patients with incomplete (Simpson grades III and IV) resection and high Ki67-MIB1 values, especially at non-skull base localization and with low PR values, require a closer short-term clinical and radiologic follow-up in the first years after surgery.

Widening the Operative Corridor-Evaluating the Transcortical Approach to Giant Falcine Meningiomas

BACKGROUND

Giant falcine meningiomas are surgically complex as they are deep in location, concealed by normal brain parenchyma, in close proximity to various neurovascular structures, and frequently involve the falx bilaterally. Although classically accessed using a bifrontal craniotomy and interhemispheric approach, little data exist on alternative operative corridors for these challenging tumors. We evaluated perioperative and long-term outcomes in patients undergoing transcortical resection of giant bilateral falcine meningiomas.

METHODS

From 2013 to 2022, fourteen patients with giant bilateral falcine meningiomas treated via a transcortical approach at our institution were identified. Perioperative and long-term outcomes were evaluated to determine predictors of adverse events. Corticectomy depth was also analyzed to determine if it correlated with increased postoperative seizure rates.

RESULTS

57.1% of cases were WHO grade 2 meningiomas. Average tumor volume was 77.8 ± 46.5 cm3 and near/gross total resection was achieved in 78.6% of patients. No patient developed a venous infarct or had seizures in the 6 months after surgery. Average corticectomy depth was 0.83 ± 0.71 cm and increasing corticectomy depth did not correlate with higher risk of postoperative seizures (P = 0.44). Increasing extent of tumor resection correlated with lower tumor grade (P = 0.011) and only 1 patient required repeat resection during a median follow-period of 24.9 months.

CONCLUSIONS

The transcortical approach is a safe alternative corridor for accessing giant, falcine meningiomas, and postoperative seizures were not found to correlate with increasing corticectomy depth. Further prospective studies are necessary to determine the best approach to these surgically complex lesions.

Falcine meningioma: FEBAIR principles in a "Grade Zero" concept application - 2D operative video

Background

Falcine meningiomas account for 5% of intracranial meningiomas. They may involve the eloquent cortex as well as vascular structures. Gross-total resection with additional margins has been shown to be beneficial to patients and has been associated with a reduction in disease recurrence.

Case Description

A 57-year-old patient presented with recurrent frontal headaches that worsened when lying down. Magnetic resonance imaging showed a large lesion with homogeneous enhancement attached to the anterior third of the falx cerebri at the right frontal lobe, causing significant compression, and suggesting a meningioma.

Conclusion

This operative video highlights the application of 1st-time, exposure, bone removal, arachnoid, irrigation, and reconstruction principles for safely and effectively removing a large falcine meningioma using the "grade zero" concept for maximal resection.

Endoscopic Ipsilateral Interhemispheric Approach for Middle-Third Falcine Meningioma: A Case Report and Literature Review

Middle-third falcine meningiomas (FMs) are usually hidden deep under the eloquent cortex and abundant bridging veins, which represent the main hindrances to surgical access. The endoscopic approach has the advantages of wide visualization and free visual axis without areas of visual blindness, which allows for the resection of FMs with good visualization in a narrow space, especially in deep operations. Here, we report a case of a middle-third FM treated using the endoscopic ipsilateral interhemispheric approach. A 55-year-old female who had suffered a headache for 6 months without other remarkable symptoms was diagnosed with middle-third FM combined with imaging evaluation. According to the imaging performance and anatomical features, we scheduled the endoscopic ipsilateral interhemispheric approach to access and remove the tumor. Consequently, gross total tumor resection was achieved without surgery-related complications. After the surgery, the patient had an uneventful recovery and was discharged with no neurological deficit. During the 24-month follow-up, the patient's condition remained favorable, with no tumor recurrence. In our opinion, the endoscopic ipsilateral interhemispheric approach is a feasible surgical strategy for FMs, which deserves further exploration as a treatment option.

Parasagittal Meningiomas: Prognostic Factors for Recurrence

The term parasagittal meningioma applies to those tumors that are associated with the superior sagittal sinus (SSS), originating from the dura mater in close relation to the parasagittal wall or angle, with no intervening brain tissue, possibly extending to the dura of the convexity and/or falx cerebri.(Cushing et al., Meningiomas: their classification, regional behaviour, life history, and surgeical and results. Hafner, 1938) They make up about 20-30% of all meningiomas. There is a vast literature correlating the Simpson grade of resection with later recurrence. Frequent involvement of the superior sagittal sinus (SSS) by these tumors means that the optimal treatment recommended in the literature-complete resection, including of the dural base-is one of the most challenging.

Endoscopic Contralateral Interhemispheric Transfalcine Keyhole Approach for Large Falcine Meningiomas

OBJECTIVE

Falcine meningioma is usually approached ipsilaterally, and the technique for tumor removal has traditionally been performed under microscopy. We report a surgical procedure for large falcine meningioma by an endoscopic contralateral interhemispheric transfalcine keyhole approach.

METHODS

The study period was from September 2019 to March 2021. Study participants were patients with World Health Organization grade I meningioma showing falx attachment, excluding neurofibromatosis, who underwent initial surgery at our institution. The surgical procedure begins with a small contralateral craniotomy of about 3 cm, followed by insertion of an endoscope. The tumor attachment to the falx is excised, exposing the tumor. Internal decompression is performed, and the lesion is dissected from the surrounding brain before removal through the falx.

RESULTS

An endoscopic contralateral interhemispheric transfalcine keyhole approach was used to resect 4 cases of large falcine meningioma. The mean operation time was 265 minutes (range: 216-294 minutes), achieving Simpson grade I removal in all cases. No evidence of cerebral infarction, cerebral edema, or new neurological complaints related to impaired venous return was seen using this surgical method.

CONCLUSIONS

In the case of falcine meningioma, the endoscopic keyhole contralateral technique allows detachment of the tumor from the falx and safe manipulation in a minor field of view. In addition, because the craniotomy is smaller and the operation time is shorter, this procedure offers a less-invasive approach for the patient. This technique is thus, in our opinion, quite advantageous.

Transcortical resection of a giant bilobed falcine meningioma

INTRODUCTION

Falcine meningiomas present significant surgical challenges because they often involve the falx bilaterally, are concealed by a significant amount of normal brain parenchyma and are frequently deep in location and in close proximity to the anterior cerebral arteries. Many prefer the interhemispheric approach for these lesions, but this operative corridor is not without risk as venous infarctions and cortical injury can occur.

CLINICAL PRESENTATION

We present an alternative technique utilizing a transcortical approach to resect a giant, bilobed falcine meningioma in a 68-year-old female who presented with progressive abulia, urinary incontinence, and bilateral lower extremity weakness over 2 years. A unilateral right frontal craniotomy and a corticectomy through the right superior frontal gyrus was used to safely resect the entire tumor. The patient tolerated the procedure well and was discharged home without issue. Pathology demonstrated that the lesion was an atypical meningioma and she subsequently received adjuvant fractionated radiotherapy. At 2-year follow-up, she has no neurologic deficits, never developed any postoperative seizures and has not had any evidence of tumor recurrence.

CONCLUSION

The transcortical approach can be used as a safe alternative for resecting falcine meningiomas without adding significant undue risk to the patient.

Sugita-Kobayashi Maneuver for Preservation of Large Bridging Veins in the Interhemispheric Approach: 2-Dimensional Operative Video

Giants of neurosurgery have made contributions that might at times seem to be minor maneuvers but have a major impact on safe surgery, such as Sugita and Kobayashi's description of the preservation of the bridging sagittal veins.1 The interhemispheric approach is haunted by risk to the bridging veins and resultant venous infarction. At the midsegment, this could produce devastating neurological deficits.2 This is an especially critical factor in falcine meningiomas in which the location of the tumor narrows the options for the surgical corridor, particularly if an additional falcine margin, "Grade Zero" resection, is to be performed.3 Detailed preoperative neuroimaging workup is required to plan the appropriate surgical strategy and minimize risk for venous complications. This may include magnetic resonance or computed tomography venogram, dynamic computed tomography angiography,4 or in some cases formal angiography to assess the relationship with the superior sagittal sinus, the anatomy of parasagittal bridging veins in relation to the lesion, and the patterns of collateral venous drainage. While bridging veins may be displaced, compressed, or obscured by tumor involvement,5 microsurgical technique can facilitate the safe identification and preservation of this crucial anatomy. Bridging veins are separated from the underlying cortex to a distance from the sinus, allowing for improved relaxation of the ipsilateral cortex, without venous compromise.1,6 Herein, we demonstrate a case of a large falcine meningioma with a "Grade Zero" resection, with mobilization of the parasagittal bridging veins to develop the interhemispheric surgical corridor. The patient consented for surgery.

Biology and Treatment of Meningiomas: A Reappraisal

Meningiomas are largely indolent tumors with a benign clinical course, but a minority exhibit aggressive behavior characterized by rapid growth, neurologic deficits, and increased mortality. Identifying high-risk patients requiring intervention is challenging, but recent insights into meningioma biology provide a useful guide for decision making. Standard of care for recurrent or biologically aggressive tumors consists of surgery and radiation therapy. Systemic therapies targeting vascular endothelial growth factor signaling and somatostatin analogues are potential options for those with refractory disease but display only modest activity. New paradigms in meningioma clinical trial design provide hope for improved options in the future.

Falx Cerebelli Meningioma: Case Report of a Rarely Occurring Tumor, Management Nuances, and Literature Review

The falx cerebelli is a small crescent fold of dura mater that is attached to the internal occipital crest and projects forward into the posterior cerebellar notch between the cerebellar hemispheres. We report a rare case of a 61-year-old female who presented with a 1-month history of headache and gait instability. Imaging findings were suggestive of a meningioma arising from the falx cerebelli. Complete surgical resection was achieved with a standard posterior fossa midline approach. Duraplasty was performed using animal allograft dura (Duraguard) and additional layers of oxidized cellulose preparation (Surgicel), fibrin sealant, and nonsuturable collagen matrix (Duragen) were utilized to reduce the risk of a cerebrospinal fluid leak. Pathology confirmed a World Health Organization (WHO) grade-I meningioma. Postoperatively, patient with asymptomatic thrombosis of the left transverse/sigmoid sinuses and later with a pseudomeningocele managed with a lumbar drain. To our knowledge, this is the second documented case in the literature. We discuss intraoperative nuances and unique aspects in the postoperative care and management of these patients.

The Dural Dark-Side Approach for falcine and tentorial meningioma: A surgical series of five patients

INTRODUCTION

Falcine or tentorial meningioma can be complex to resect. When large meningiomas are located in eloquent areas, a direct ipsilateral surgical approach may cause brain injury and postoperative neurological deficits. In this series, 5 patients were surgically treated using a contralateral transfalcine or transtentorial approach to minimize brain retraction. This strategy was called the Dural Dark-Side Approach (DDSA). The aim was to analyze the quality of tumor resection and postoperative outcome.

MATERIAL AND METHODS

In our department, from June 2018 to January 2020, 5 patients underwent microsurgical DDSA for resection of 4 falcine and 1 tentorial meningioma. All tumors were selected on the following two criteria: large>40mm diameter tumor, with surrounding functional cortex. Clinical and radiologic data were retrospectively analyzed.

RESULTS AND DISCUSSION

Mean follow-up was 20 months. No patients required use of a rigid retractor during surgery. Gross total resection was performed in 3 patients and near-total resection in 2. All patients had favorable neurologic outcome. Postoperative MRI showed no ipsilateral or contralateral brain lesions.

CONCLUSION

This series suggested that meticulous DDSA allows excellent resection in selected large falcine or tentorial meningioma. The approach offered a safe and effective surgical corridor without injuring the surrounding healthy parenchyma.

Review of Atypical and Anaplastic Meningiomas: Classification, Molecular Biology, and Management

Although the majority of meningiomas are slow-growing and benign, atypical and anaplastic meningiomas behave aggressively with a penchant for recurrence. Standard of care includes surgical resection followed by adjuvant radiation in anaplastic and partially resected atypical meningiomas; however, the role of adjuvant radiation for incompletely resected atypical meningiomas remains debated. Despite maximum treatment, atypical, and anaplastic meningiomas have a strong proclivity for recurrence. Accumulating mutations over time, recurrent tumors behave more aggressively and often become refractory or no longer amenable to further surgical resection or radiation. Chemotherapy and other medical therapies are available as salvage treatment once standard options are exhausted; however, efficacy of these agents remains limited. This review discusses the risk factors, classification, and molecular biology of meningiomas as well as the current management strategies, novel therapeutic approaches, and future directions for managing atypical and anaplastic meningiomas.