Convexity Meningioma Research Articles

Surgical navigation for meningioma surgery

The use of surgical navigation systems (SNSs) is well established in intracranial surgery for gliomas and metastases yet some doubt its benefit in surgery for intracranial meningiomas. In this chapter we review the authors' experiences and literature on how use of surgical navigation may be useful in craniotomy for intracranial mengingiomas. With the exception of small convexity meningiomas, finding the tumor is not a common problem. The most important issues where the capabilities of SNS can be used to the surgeon's advantage are optimizing the bone and dural opening, avoiding arterial and venous structures, defining the frontal air sinuses and determining one's location within a large tumor devoid of landmarks. Contemporary SNS can provide instantaneous localization and orientation information, as well as utilize multimodality imaging that is required to address these problems and is an effective means of optimizing surgery for many intracranial meningiomas.

Stereotactic radiosurgery for WHO grade I meningiomas

Meningiomas represent a common intracranial tumor in the adult population. Although extirpation to achieve a gross total resection or at least decrease mass effect has been the mainstay of treatment, stereotactic radiosurgery has come to play an increasingly important role in the management of patients with meningiomas. Radiosurgery utilizes highly focused, beams of ionizing radiation to inactivate tumor cells. Image guidance and a steep dose fall off are critical features of this approach. The radiobiology of radiosurgery differs in certain advantageous ways from conventional radiotherapy. Radiosurgery initially was utilized to treat recurrent or residual skull base meningiomas. As success was observed in this setting, radiosurgery has gradually expanded its role so as to treat convexity meningiomas; it is also used as an upfront treatment for patients for whom clinical and neuro-imaging findings are consistent with a meningioma. Most large series demonstrate tumor control rates for patients with grade I meningiomas in excess of 85%. Neurological function is generally preserved or improved for patients with meningiomas. However, complications can occur. Longitudinal follow-up including neurologic and radiologic assessment is required. Single and multisession stereotactic radiosurgery will likely play an expanded role in the treatment of patients with meningiomas.

Vacuum-assisted en bloc resection of large convexity meningiomas

Convexity meningiomas are common tumors encountered by neurosurgeons. Retracting, grasping, and mobilizing large convexity meningiomas can be difficult and awkward as well as place unwanted forces on surrounding neurovascular structures. The authors present a safe alternative to traditional retraction and manipulation methods by using a modified bulb syringe connected to standard surgical suction to function as a vacuum retractor. This technique allows for rapid, safe, en bloc resection of large convexity meningiomas with little to no pressure on the surrounding brain. The authors present an illustrative case and describe and discuss the technique.

Intracranial meningioma in children: Different from adult forms? A series of 21 cases

Objective Intracranial meningiomas are very rare in children, comprising only 0.4 to 4.1% of pediatric tumors and only 1.5 to 1.8% to all intracranial meningiomas. The goal of this study of pediatric meningiomas was to establish their epidemiological profile as well as their clinical and radiological features, to assess the long-term outcome, and compare this result with adult meningioma. Patient and methods We conducted a retrospective study from June 1983 to June 2007; during this period 521 patients underwent surgery for primary meningioma at the Rabat Hospital, Department of Neurosurgery. Twenty-one patients were under 16 years of age (4%). The clinical charts and imaging data were reviewed. Results The mean age was 10.3 years (range: 2 to 16 years), with 13 boys and eight girls. In one patient a neurofibromatosis was associated. The mean delay to diagnosis was 4.6 months (range: 1 to 12 months). The most common clinical sign was raised intracranial pressure (90%). Of the meningiomas diagnosed, 47% were convexity meningiomas while 24% were parasagittal and 19% were skull-base meningiomas; in two cases (9.5%) the location was intraventricular. The mean tumor diameter was 6.6 cm (range: 3 to 10 cm). A large cystic component was found in 24% of the cases. Surgery achieved a Simpson grade I resection in 47%; 62% of the tumors were grade I and 24% were grade II based on World Health Organization pathological classification. The mean follow-up period was 33 months (range: 6 to 120 months). The recurrence rate was 33%. Conclusion Pediatric meningiomas are larger than those found in the adult population; there is a male predominance with high incidence of a cystic component and high-grade meningiomas, thus explaining the increased recurrence rate despite the multimodal treatment.

Postoperative seizures following the resection of convexity meningiomas: are prophylactic anticonvulsants indicated?

Seizures in the perioperative period are a well-recognized clinical entity in the setting of brain tumor surgery. At present, the suitability of antiepileptic prophylaxis in patients following brain tumor surgery is unclear, especially in those without prior seizures. Given the paucity of tumor-type and site-specific data, the authors evaluated the incidence of postoperative seizures in patients with convexity meningiomas and no prior seizures. The authors identified 180 patients with no preoperative history of seizures who underwent resection of a convexity meningioma. Some patients received antiepileptic prophylaxis for 7 days postoperatively while others did not, based on the practice patterns of different attendings. The rates of clinically evident seizures in the first 3-4 weeks after surgery were compared. Patients who received antiepilepsy drugs (129 patients) did not significantly differ from those who did not (51 patients) in terms of age, sex, WHO tumor grade, extent of resection, rate of previous cranial surgery or radiation therapies, or use of preoperative embolization. There was a single new postoperative seizure in the entire cohort, yielding a new seizure rate of 1.9% in patients not on antiepileptic prophylaxis compared with 0% in patients on antiepileptics (p = not significant). While it is thought that the routine use of prophylactic antiepileptics may prevent new seizures in patients undergoing surgery for a convexity meningioma, the rate of new seizures in untreated patients is probably very low. Data in this study call into question whether the cost and side effects of these medications are worth the small benefit their administration may confer.

Risk profile associated with convexity meningioma resection in the modern neurosurgical era

Although meningiomas are commonly found along the supratentorial convexity, the risk profile associated with this subset of lesions in the modern neurosurgical era is unknown. The authors retrospectively reviewed the clinical course of patients with supratentorial convexity meningiomas treated during the past 10 years. All patients had undergone MR imaging within 72 hours after surgery and at least 1 year of clinical follow-up. Patients with multiple meningiomas, hemangiopericytomas, malignant meningiomas, or tumor-prone syndromes were excluded from analysis. Between 1997 and 2007, 141 consecutive patients (median age 48 years, range 18-95 years) underwent resection of a supratentorial convexity meningioma. The most common signs or symptoms at presentation were headache (48%), seizures (34%), and weakness (21%). The mean tumor volume was 146.3 cm3 (range 1-512 cm3). There were no intraoperative complications or deaths. Medical or neurosurgical morbidity was noted in the postoperative course of 14 patients, equating to a 10% overall complication rate. Postoperative surgical complications included hematoma requiring evacuation, CSF leakage, and operative site infection. Medical complications included pulmonary embolus and deep vein thrombosis requiring treatment. A Simpson Grade 0 or 1 resection was achieved in 122 patients (87%). One hundred six tumors (75%) were WHO Grade I, whereas 35 (25%) were WHO Grade II. The median clinical follow-up was 2.9 years (range 1-10 years), and the median radiographic follow-up was 3.7 years (range 1-10 years). Six patients (4%) had radiographic evidence of tumor recurrence, with 3 (2%) undergoing repeat resection. With the conservative recommendations for surgery for asymptomatic meningiomas and the advent of radiosurgery during the past 10 years, microsurgically treated convexity meningiomas are now typically large in size. Nevertheless, the patient's clinical course following microsurgical removal of these lesions is expected to be uncomplicated. The authors' findings provide a defined risk profile associated with the resection of supratentorial convexity meningiomas in the modern neurosurgical era.

A modified far-lateral approach for large or giant meningiomas of the posterior fossa

Resecting large meningiomas along the posterior fossa convexity or cerebellopontine angle (CPA) through a suboccipital approach can be challenging. Limitations include a restricted angle of view, high venous pressures, and suboptimal brain relaxation. While a far-lateral craniotomy is a viable alternative, the risks associated with condylar resection are undesirable. The authors retrospectively evaluated a modified far-lateral approach in a consecutive series of 12 patients with large or giant posterior fossa convexity and CPA meningiomas. This approach incorporates transverse-sigmoid sinus exposure and C-1 laminectomy, but there is no condylar resection. Between January 2006 and February 2008, 12 patients (mean age 52 years) presented with large or giant meningiomas of the posterior fossa convexity or CPA. The mean tumor volume was 72.6 cm3 (range 8-131 cm3). Signs and symptoms at presentation included headache (in 8 patients), cranial neuropathy (in 4), and progressive hemiparesis (in 4). There were no operative complications, and the majority of patients (9) had Simpson Grade I or II resections. There were no new permanent neurological deficits following resection, although 2 patients (17%) had transient deficits. The mean modified Rankin score decreased from 2.2 preoperatively to 0.6 postoperatively. A modified far-lateral approach to the posterior fossa and CPA allows for safe, and often total, resection of large meningiomas with minimal morbidity. While avoiding the risks of condylar resection, this microsurgical strategy allows for greater field of view, minimal venous bleeding, and immediate access to the spinal subarachnoid space.

Augmented reality neurosurgical planning and navigation for surgical excision of parasagittal, falcine and convexity meningiomas

Objective. To assess the utility of pre-operative 3-dimension (3D) visualisation and surgical planning with the Dextroscope™ in combination with the use of DEX-Ray—a novel augmented reality surgical navigation platform for resection of meningiomas in the falcine, convexity and parasagittal regions.Methods and Results. Magnetic resonance imaging (MRI) and magnetic resonance venogram (MRV) images of the patients were reconstructed in 3D using the Dextroscope workstation. Using a variety of available tools, we were able to view the tumour in various surgical angles and appreciate the intricate relationship of the tumour with respect to the surrounding structures and venous anatomy. Critical draining veins both superficial and deep to the tumour were well visualised. By varying the transparency of the overlying scalp and bone we were able to preoperatively determine the ideal size of our scalp flap and bone window for surgical approach. The Dextroscope enabled us to simulate surgical opening and various trajectories of approach while the DexRay virtual reality navigation system enabled the transfer of the Dextroscope 3D planning data into the operating by displaying it in real-time video-augmented mode which further enhanced the appreciation of the tumour's location in 3D space. Four patients underwent total excision of their meningioma while one patient had near total excision with a small residual remnant left behind at the medial third of the superior sagittal sinus. All 5 patients had good neurological recovery post-operatively.Conclusion. The use of the Dextroscope for pre-operative surgical planning allows for appreciation of complex anatomical relationships in 3D. This appreciation is further translated for use during surgical navigation utilizing the DEX-Ray platform that provided us with the superior advantage of allowing fast and accurate surgical resection confidently.

Intracranial Hemorrhage Associated With Convexity Meningioma After Cerebral Angiography -Case Report-

A 63-year-old female developed left hemiparesis caused by intracranial intratumoral and peritumoral hemorrhage with cerebral herniation 4 days after cerebral angiography to evaluate right convexity and petrosal meningiomas. The cerebral angiography procedure may have caused the tumoral edema and intracranial hemorrhage because computed tomography on admission revealed the right convexity meningioma as slightly low density compared to before the hemorrhage. Administration of contrast medium is known to cause complications involving microcirculatory collapse and blood-brain barrier dysfunction associated with brain tumors. Therefore, the contrast medium may have affected the meningioma after cerebral angiography.

Osteochondroma of the convexity: pathologic-neuroimaging correlates of a lesion that mimics high-grade meningioma

Intracranial chondromas are uncommon benign lesions usually attached to dura and located over the convexity of the skull. Osteochondromas are even rarer and additionally contain a benign bony component. Both lesions are reportedly difficult to distinguish from meningiomas on pre-operative neuroimaging studies, although few detailed pathologic-neuroimaging correlation studies have appeared in the literature, particularly for intracranial osteochondromas. A 33-year-old woman with a 4-year history of headaches presented with recent onset of left-sided muscle spasms and weakness. Two days prior to admission to our hospital, neuroimaging studies had shown a large right convexity mass with unusual multifocal bright signal intensities throughout an otherwise isointense mass. The bright signals were interpreted as showing multifocal hemorrhage and the mass was felt to be a convexity meningioma. However, subsequent catheter angiography characterized the lesion as being avascular. The mass was resected en bloc. Extensive histological sectioning revealed a benign osteochondroma predominantly composed of lobules of hypocellular cartilage. Microdissection of the different components revealed that the multifocal, spicule-like bright foci interpreted as hemorrhage on neuroimaging studies were instead foci of benign bone containing metaplastic bone marrow with trilineage hematopoietic cell populations and adipose tissue. Centrally, the hilum of the lesion contained avascular loose connective tissue. No recent or remote hemorrhage was identified anywhere in the lesion. Rare convexity osteochondromas may be mistaken for high-grade meningiomas on neuroimaging studies; their avascular nature, coupled with their complex signal pattern can serve as clues to the correct pre-operative diagnosis.

Stereotactic radiosurgery for convexity meningiomas

Meningiomas of the cerebral convexity are often surgically curable because both the mass and involved dura mater can be removed. Stereotactic radiosurgery has become an important primary or adjuvant treatment for patients with intracranial meningiomas. The authors evaluated clinical and imaging outcomes in patients with convexity meningiomas after radiosurgery. The patient cohort consisted of 125 patients with convexity meningiomas managed using radiosurgery at some point during an 18-year period. The patient series included 76 women, 55 patients who had undergone prior resection, and 6 patients with neurofibromatosis Type 2. Tumors were located in frontal (80 patients), parietal (24 patients), temporal (12 patients), and occipital (9 patients) areas. The WHO tumor grades in patients with prior resections were Grade I in 34 patients, Grade II in 15 patients, and Grade III in 6 patients. Seventy patients underwent primary radiosurgery and therefore had no prior histological tumor diagnosis. The mean tumor volume was 7.6 ml. Radiosurgery was performed using the Leksell Gamma Knife with a mean tumor margin dose of 14.2 Gy. Serial imaging was evaluated in 115 patients (92%). After primary radiosurgery, the tumor control rate was 92%. After adjuvant radiosurgery, the control rate was 97% for Grade I tumors. The actuarial tumor control rates at 3 and 5 years for the entire series were 86.1+/-3.8% and 71.6+/-8.6%, respectively. For patients with benign tumors (Grade I) and those without prior surgery, the actuarial tumor control rate was 95.3+/-2.3% and 85.8+/-9.3%, respectively. Delayed resection after radiosurgery was performed in 9 patients (7%) at an average of 35 months. No patient developed a subsequent radiation-induced tumor. The overall morbidity rate was 9.6%. Symptomatic peritumoral imaging changes compatible with edema or adverse radiation effects developed in 5%, at a mean of 8 months. Stereotactic radiosurgery provides satisfactory control rates either after resection or as an alternate to resection, particularly for histologically benign meningiomas. Its role is most valuable for patients whose tumors affect critical neurological regions and who are poor candidates for resection. Both temporary and permanent morbidity are related to brain location and tumor volume.

Intracranial Meningiomatosis Causing Foster Kennedy Syndrome by Unilateral Optic Nerve Compression and Blockage of the Superior Sagittal Sinus

The original description of the Foster Kennedy syndrome included the clinical triad of optic disc pallor in one eye, optic disc edema in the other eye, and reduced olfaction caused by space-occupying anterior fossa masses. The optic disc pallor was attributed to direct compression of the intracranial optic nerve, the optic disc edema to increased intracranial pressure from mass effect, and the reduced olfaction to direct compression of the olfactory nerve. We report a patient with the ophthalmic features of the Foster Kennedy syndrome from meningiomatosis. A meningioma compressed one optic nerve to cause impaired visual function. Convexity meningiomas compressed the superior sagittal sinus to impair cerebral venous drainage, increased intracranial pressure, and papilledema in the other eye. This is the first report of the Foster Kennedy syndrome caused by this mechanism.

Middle meningeal artery aneurysm associated with meningioma

Middle meningeal artery aneurysm associated with meningioma is extremely rare, and only two cases have previously been reported. In our case, a 72-year-old woman with convexity meningioma underwent preoperative cerebral angiography, which revealed a flow-related aneurysm on the middle meningeal artery. Embolization of the aneurysm was performed with N-butycyanoacrylate glue, and complete obliteration was confirmed under craniotomy. In order to eliminate the risk of preoperative rupture resulting in intracranial hemorrhage, endovascular embolization with liquid glue is safe and effective for this kind of aneurysm.

Delayed Enlargement of Brain Edema After Resection of Intracranial Meningioma -Two Case Reports-

Two patients underwent uneventful total removal of convexity or trigone meningioma, but subsequently edema enlarged causing symptoms 3-4 weeks later. Gradual improvement was obtained by steroid administration in 1 patient and re-craniotomy in 1 patient. The histological findings in Case 1 were not confirmed, but inflammatory reaction against residual microfibrillar collagen hemostat (MCH) may have developed. The specimen from around the cyst in Case 2 showed moderate staining for vascular endothelial growth factor (VEGF). VEGF secreted by the tumor might have resulted in spread of inflammation due to MCH in the brain parenchyma. Furthermore, inflammatory reactions may have obstructed or formed a one-way communication in the inferior horn and residual cavity, resulting in malabsorption of cerebrospinal fluid. Postoperative edema with the timing in these cases is difficult to anticipate. However, the risk of this phenomenon can probably be minimized by ensuring that MCH is removed as effectively as possible after use, or by refraining from use in the brain parenchyma and by taking care to connect the residual cavity to the ventricular system, particularly if the tumor contacts a cerebral ventricle.

Primary brain tumors associated with cerebral aneurysm: report of three cases

The primary brain tumors associated with cerebral aneurysms are rare in neurosurgical practice. The present article constitutes an evaluation of the management of coexistent primary brain tumor and cerebral aneurysm. A retrospective study of three cases of primary brain tumor with cerebral aneurysm was performed. We evaluated the complications and clinic outcomes by assessing the clinical and imaging findings. Case 1 presented with a subarachnoid hemorrhage from an aneurysm of the anterior communicating artery, with an incidental left frontal oligodendroglioma. Case 2 presented with chronic headache due to left frontal convexity meningioma, with proximal internal carotid artery aneurysm which was found incidentally during preoperative magnetic resonance angiography. Case 3 was admitted to our hospital complaining of headache, memory disturbance, and weakness in her left lower extremity. Magnetic resonance imaging revealed right frontal lymphoma and an unruptured aneurysm at the left middle cerebral artery. Preoperative magnetic resonance imaging revealed right frontal lymphoma and unruptured left middle cerebral artery. The frequency of primary brain tumor and cerebral aneurysm coexistence is increasing due to improvements in high-resolution imaging. In these complicated cases, the management will differ according to each pathology present, and this is an important problem for a neurosurgeon.

Dural bridge sutures to prevent sinking of dural substitutes: technical note

Following Simpson Grade 1 excision of large convexity meningioma there is often a need for synthetic dural substitutes. One problem with some of these grafts is that they lack tensile strength when wet and therefore sink into the cavity left following removal of the meningioma. A simple method to prevent 'sinking' or sagging of such synthetic dural grafts is described and illustrated.

Is Bone Enhancement a Helpful Finding in the Diagnosis of Convexity Meningiomas?

We have assessed the enhancement of the overlying bone as a new finding in patients with convexity meningioma. This finding was present in 68.6% of cases in our series. This finding was found very helpful in the differential diagnosis of atypical and cystic meningiomas.

Pathodiagnostic parameters for meningioma grading

Meningiomas are usually slow-growing benign tumors, for which complete removal can be difficult and recurrence is an issue. In this study the relationship between pathodiagnostic parameters, histological grade, and MIB-1 monoclonal antibody expression in meningioma diagnosed over 10 years in Shohada Hospital, Tehran, was assessed. All cases were re-evaluated according to the latest World Health Organization (WHO) Classification. Between January 1997 and December 2006, a total of 4885 intracranial tumors were diagnosed at Shohada Hospital, 378 (7.74%) of which were meningiomas. All slides stained with hematoxylin and eosin were reviewed by two independent pathologists and all the diagnoses reconfirmed; histological anaplasia was classified according to the grading of the WHO Working Group 2000 as benign (Grade I), atypical with incipient signs of anaplasia (Grade II), or overtly anaplastic (Grade III). The mean age of patients with meningiomas was 49.11 ± 12.99 years (range 6–78 years, median = 50); females outnumbered males by a ratio of 1.7 to 1. Presenting symptoms were headache/vertigo (66.7%) and epilepsy (28.5%). Convexity meningiomas were most common, followed by meningiomas of the sphenoid ridge and cerebellopontine angle. There was no relationship between the location of the tumor and the histopathological features. The association between mitotic rate, increased cellularity, nucleo-cytoplasmic ratio, and sheet-like spreading was especially strong. Histopathological study of completely resected meningiomas showed that loss of architecture, frequent mitotic figures, a high cellularity, increased nucleo-cytoplasmic ratio, a prominent nucleolus, brain invasion, and necrosis were correlated with the grade of the meningiomas. Overall, the mitotic count was the most important marker for tumor grade.

SURGERY FOR CONVEXITY MENINGIOMAS

Meningiomas that occur over the convexity of the brain are the most common meningiomas, but little has been published about their contemporary management. We aimed to analyze a large series of convexity meningiomas with respect to surgical technique, complication rates, and pathological factors leading to recurrence. We retrospectively reviewed 163 cases of convexity meningiomas operated on in our institution by the senior author (PMB) between 1986 and 2005. The median follow-up time was 2.3 years (range, 1-13 yr). Convexity tumors represented 22% of all meningiomas operated on. There was a female:male ratio of 2.7:1. Median age was 57 years (range, 20-89 yr). Image-guided surgery was used on all cases in the last 5 years. The 30-day mortality rate was 0%. The incidence of new neurological deficits was 1.7%, and the overall complication rate was 9.4%. The pathology of the tumors was benign in 144 (88.3%), atypical in 16 (9.8%), and anaplastic/malignant in 3 (1.8%). In six of the cases designated "benign," there were borderline atypical features. The 5-year recurrence rate for benign meningiomas was 1.8%, atypical meningiomas 27.2%, and anaplastic meningiomas 50%. The two cases of benign tumor recurrences involved tumors with borderline atypia and high MIB-1 indices. The borderline atypical cases had a 5-year recurrence-free survival rate of only 55.9%, more closely approximating that of tumors designated "atypical." Convexity meningiomas can be safely removed using modern image-guided minimally invasive surgical techniques with a very low operative mortality. Benign convexity meningiomas having a Simpson Grade I complete excision have a very low recurrence rate. The recurrence rates of atypical and malignant tumors are significantly higher, and borderline atypical tumors should be considered to behave more like atypical rather than benign lesions. Longer-term follow-up data are needed to more accurately determine the recurrence rates of benign meningiomas.

An Updated Comparison of Early Complications for Patients with Convexity and Parasagittal Meningioma Treated with either Stereotactic Radiosurgery or Fractionated Stereotactic Radiotherapy

An Updated Comparison of Early Complications for Patients with Convexity and Parasagittal Meningioma Treated with either Stereotactic Radiosurgery or Fractionated Stereotactic Radiotherapy