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Purpose: The optic nerve sheath meningioma (ONSM) is one of the most challenging tumors in orbital surgery. From the perspective of mental health and patient needs, we analyzed the necessity and importance of the endoscopic transnasal approach (ETA) combined with optic nerve transection (ONT) in gross-total resection (GTR) in ONSM patients with residual vision and aim to broaden the use of ONT for specific people., Methods: The authors included patients with ONSMs who were treated between 2014 and 2022. We divided those cases into two groups named ETA group and lateral orbitotomy approach (LOA) group. We present the application of ETA and analyze the preoperative indication of the ONT and compared the advantages and disadvantages between ETA and LOA. The degree of tumor resection was based on imaging and surgical evaluation., Results: A total of 23 patients with ONSM were included. Sixteen patients underwent ETA, and seven underwent LOA. Among ETA cases, GTR was achieved in 14 patients with ONT and most patients maintained normal eye movement function (75%) and morphology (93.75%). In the ETA group, 14 patients experienced vision loss, while two other patients saw improvements in vision. And proptosis was alleviated (5.20 ± 2.34 vs 0.27 ± 0.46, p < 0.0001). Six patients with blindness and proptosis of the LOA group resulted in GTR with ONT and ophthalmectomy. Although intracranial extension and recurrence included no cases in the two groups, a significant psychological gap was presented due to cosmetic problems., Conclusions: Under the premise of reducing damage and improving aesthetics, the selection of ETA combined with ONT to gross-total resect ONSMs successfully provides a minimally invasive access with acceptable complications. As an important adjunct to GTR in the surgical treatment of ONSM, the scope of ONT application should be expanded to relieve the patient's psychological burden., (© 2024. The Author(s).)

Background: Management of patients with optic nerve sheath meningiomas (ONSMs) is controversial and the treatment strategy in this patient group is still up for discussion. Transnasal endoscopic orbital and optic nerve decompression aims to reduce the pressure in the orbit and on the optic nerve and thereby prevent vision loss. This article presents material from 7 cases of transnasal endoscopic orbital decompression., Methods: The study design is a retrospective cohort study. The aim was to include all patients with a meningioma residing along the nerve sheath and who were operated using endoscopic transnasal decompression of the orbit and if needed the optic canal at Odense University Hospital. Data from the medical records were collected and pre- and postoperative eye examinations were compared. In addition, it was recorded whether there were complications to the procedure and whether additional treatments were given., Results: In total, 4 women and 3 men were included in the study. Four out of 7 patients experienced improvement in vision after the operation. One patient experienced unchanged vision and 2 patients experienced deterioration of vision after surgery., Conclusions: The current report of 7 patients with ONSM shows promising results for this surgical procedure as 4 out of 7 patients experienced improvement in their vision at follow-up examinations. The 2 patients who experienced deterioration of vision already had severely reduced vision preoperatively, which indicates that surgery should be considered before the vision becomes significantly reduced., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Meningiomas arising from or adjacent to the optic nerve sheath meningioma (ONSM) are management challenges because of their risk of visual loss. Stereotactic radiosurgery (SRS) is a minimally invasive modality that can be added as adjuvant treatment for patients whose tumor has progressed or recurred after initial resection., Methods: The authors retrospectively reviewed 2,030 meningioma patients who underwent SRS between 1987 and 2022. In total, 7 patients (4 females; median age = 49) were found with tumors originating from the optic nerve sheath. None of the patients had tumors that engulfed the optic nerve as such tumors typically undergo fractionated radiation therapy (FRT) to preserve vision. The clinical history, visual function, and radiographic and neurological findings were characterized. Outcome measures included visual status, tumor control, and the need for additional management., Results: All patients underwent either initial gross total (n = 1) or partial surgical resection (n = 6) before SRS. Two patients with progressive tumor growth also had SRS after failing additional fractionated radiation after surgery (54 Gy, 30 fractions for both patients). The median time between the date of surgery and the SRS procedure date was 38 months. The Leksell Gamma Knife was used to deliver a margin dose of 12 Gy (range: 8-14 Gy) to a median cumulative tumor volume of 3.3 cc (range: 1.2-18 cc). The median maximal optic nerve radiation dose was 6.5 Gy (range: 1.9-8.1 Gy). After SRS, the median follow-up time was 130 months (range: 26-169 months). Two patients showed local tumor progression at 20 and 55 months after SRS. Four had stable visual function, 2 experienced improved visual acuity, and 1 patient had visual deterioration., Conclusions: Meningiomas arising from (but not engulfing the optic nerve) represent management quandaries after failed initial surgical removal. In this experience, salvage SRS was associated with tumor control and vision preservation in 5 of 7 patients. Additional experience with this strategy may further define the role of SRS both as a salvage and primary option., (Copyright © 2023 by North American Neuro-Ophthalmology Society.)

Purpose: To report a case of a globular primary optic nerve sheath meningioma managed surgically with improvement in vision and review the literature for outcomes of purely intraorbital exophytic-globular primary optic nerve sheath meningiomas managed surgically., Methods: A literature review was conducted using Google Scholar and PubMed with the search terms "primary optic nerve sheath meningioma," "surgery," "exophytic," and "globular." Articles were included if they were available in English. Individual cases from the reviewed articles were included if the tumor was purely intraorbital with a globular or exophytic morphology, was managed with total or subtotal surgical excision, and visual outcomes were reported. Cases were excluded if the tumor extended intracanalicularly or intracranially, tumor morphology was unknown, or surgical management consisted of biopsy, optic nerve sheath decompression, or optic canal decompression rather than tumor debulking., Results: A total of 28 patients with intraorbital globular-exophytic primary optic nerve sheath meningiomas managed surgically have been reported in the literature. Vision improved in 29% (n = 8/28) and remained stable in 43% (n = 12/28) of patients. Furthermore, patients with good (Snellen notation ≥ 0.5) vision (n = 10) typically retained good vision postoperatively and at follow-up, with 1 patient experiencing a decline to poor (Snellen ≤0.1) vision at the last follow-up (92 months postoperatively). Similarly, patients with fair (Snellen notation >0.1 and <0.5) vision (n = 5) often improved to good vision (n = 3) or stayed at fair vision (n = 1), with 1 declining to poor vision at postoperative hospital discharge., Conclusions: Surgical management of exophytic or globular optic nerve meningiomas does not universally lead to vision loss and may be appropriate in select patients., Competing Interests: The authors have no financial or conflicts of interest to disclose., (Copyright © 2023 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc.)

Purpose: To assess the long-term effects of fractionated stereotactic radiotherapy (fSRT) for the treatment of (presumed) benign intraorbital tumours on visual acuity, visual fields, globe and eyelid position, and complications including radiation retinopathy and deviations of retinal nerve fibre layer (RNFL) on OCT., Methods: Multi-centre retrospective follow-up study of a consecutive series of 25 patients treated in the Rotterdam Orbital Center (collaboration between Erasmus Medical Center and Rotterdam Eye Hospital) between 2002 and 2018. Data on the dose of fSRT, visual acuity, Humphrey field analyser (HFA) perimetry, globe and eyelid position were obtained from the medical records., Results: In this retrospective consecutive series of 25 patients with a median follow-up of 104 months (range 48-215 months), 80.0% of the patients had presumed optic nerve sheath meningioma and 20.0 % presumed cavernous haemangioma with signs suggestive of recent growth. In most patients, a better visual acuity and RNFL thickness were observed after stereotactic radiotherapy. Improvement of the visual field defects was observed after treatment, with a mean deviation of -14.98 dB (12.9 SD) before treatment versus -4.56 dB (10.8 SD) after treatment, respectively. Significant, but small changes in exophthalmometry values were observed with a mean of 14.92 mm (7.9 SD) versus 13.79 mm (7.3 SD) after treatment, respectively. Only 3 patients (15.0%) developed radiation retinopathy after stereotactic radiotherapy. All patients with radiation retinopathy had presumed optic nerve sheath meningioma., Conclusions: Based on our results, fSRT is an effective treatment modality for this subset of orbital tumours with few complications and good long-term visual and cosmetic outcomes. FSRT is non-invasive and safer than surgery for lesions in the posterior orbit or around the optic nerve., (© 2022. The Author(s), under exclusive licence to The Royal College of Ophthalmologists.)

Primary optic nerve sheath meningioma (pONSM) is one of the most challenging tumors to manage. Although surgical excision may be considered a treatment option to maintain visual function, the safety of surgery remains debatable due to the non-negligible risk of optic nerve injury. pONSM often grows concentrically around the optic nerve; however, it can also demonstrate an exophytic growth from the optic nerve. The risk of surgical excision of pONSM may vary based on the tumor's growth pattern and area of contact with the optic nerve; however, there has been no detailed report on risk stratification to date. The authors present an illustrative case of an exophytic pONSM which was removed surgically without complications, suggesting that tumor morphology may also influence the surgical risk. In this report, the imaging and intraoperative features of exophytic pONSM are presented in detail, and the risk factors for complications are discussed., (Copyright © 2023 by Mutaz B. Habal, MD.)

Background: Optic nerve sheath meningiomas (ONMs) are often managed with radiotherapy (RT) with the goal of achieving radiographic local control (LC) and preventing deterioration of visual acuity (VA). We aimed to perform a systematic review and meta-analysis of outcomes for patients with ONM treated with RT., Methods: The PICOS/PRISMA/MOOSE selection criteria were used to identify studies. Primary outcomes were stable or improved VA and radiographic LC at last follow-up. The secondary outcomes were incidences of radiation-induced retinopathy and xerophthalmia and stable or improved visual fields (VFs). Weighted random-effects meta-analyses using the DerSimonian and Laird methods were conducted to characterize effect sizes. Mixed-effects regression models were used to examine potential correlations between gross tumor volume (GTV) and outcomes., Results: In total, 444 patients with ONM across 20 published studies were included. The estimated LC rate was 99.8% (95% confidence interval [CI], 98.3%-100%), and the estimated proportion of patients with stable or improved VA or VF was 89.7% (95% CI, 86.2%-92.4%) and 93.3% (95% CI, 89.5%-95.8%), respectively. Estimated incidences of radiation-induced retinopathy and xerophthalmia were 7.2% and 10.1%, respectively. GTV was significantly associated with VA (P = 0.014) with estimated VA rates of 96.4%, 91.4%, and 80.5% for GTVs of 2.0, 3.0, and 4.0 cm 3 , respectively., Conclusions: RT was well tolerated, with excellent LC achieved. Nearly 90% of patients noted either stability or improvement in VA and VF. Larger ONMs were associated with poorer VA., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Purpose: The purpose of this paper is to provide novel insight into the rare pediatric meningiomas., Methods: We retrospectively analyzed pediatric surgical cases of meningioma during 2002 to 2017 in our institution. The preoperative, intraoperative, and the postoperative status were collected to find any unique features that has not reported in the past., Results: Nine surgeries out of 5 patients were identified. The mean age was 7 years old (range 1-14 years old). Four patients were females. The mean tumor diameter was 52 mm (range 23-81 mm). The tumor locations were optic nerve sheath, Sylvian fissure, parasagittal, trigone of the lateral ventricle, and cerebellopontine angle. The Sylvian fissure meningioma without dural attachment (MWODA) was found in a 15-month-old female. A relapsed parasagittal meningioma showed regression in histological grade and residual tumor demonstrated spontaneous regression. In the initial surgeries, Simpson grade 1 resection was achieved in 2 cases. The pathological diagnoses were 1 meningothelial, 1 metaplastic, 2 atypical, and 1 clear cell meningiomas. The mean postoperative follow-up period was 71 months. Three patients experienced recurrence of the tumor. At the latest follow-up, all patients were free of radiological tumor recurrence or regrowth with a mean follow-up of 4 years (range 1-6.9 years). All patients were in the modified Rankin scale of 0-1., Conclusions: MWODA is not considered to be rare in pediatric meningioma and should be included in the differential diagnosis. We presented a histologically regressed relapsed meningioma, which spontaneously regressed after subtotal resection. In the case of recurrent meningioma, surgical resection and adjuvant radiation therapy could be effective for long-term control of the tumor.

We analysed the long-term outcomes of patients with primary optic nerve sheath meningioma (ONSM) treated with stereotactic radiotherapy (SRT). 26 patients with primary ONSM were treated with SRT between 2004 and 2013 at a single institution. SRT was delivered with image guidance to a median dose of 50.4 Gy in 28 fractions. 4 patients had prior surgical debulking. At a median radiological follow-up of 68 months, the MRI based tumour control was 100%. Visual acuity improved in 10 (38.4%), remained stable in 10 (38.4%) and was reduced in 6 (23.1%) patients following treatment. Stable or improved vision post-treatment was seen in 92.3% of patients with good pre-treatment vision (best corrected visual acuity 6/18 or better), compared to only 61.5% of patients with poor pre-treatment vision (best corrected visual acuity 6/24 or worse). Overall, the treatment was well tolerated with no Grade 2 or greater acute toxicity. Minimal other ophthalmic complications were seen with only one patient developing late onset Grade 3 radiation retinopathy., (Copyright © 2019. Published by Elsevier Ltd.)

Objective: Although meningiomas frequently involve the optic nerve, primary optic nerve sheath meningiomas (ONSMs) are rare, accounting for only 1% of all meningiomas. Given the high risk of vision loss with these tumors, surgical intervention is seldom considered, and radiation or observation is commonly applied. Here, the authors describe the visual outcomes for a series of patients who were treated with surgery aiming at maximal tumor resection and highlight their prognostic factors., Methods: The authors retrospectively analyzed the data for 8 patients with intracanalicular ONSMs who had been surgically treated by the senior author (O.A.) between 1998 and 2016. Meningiomas extending into the optic canal from the intracranial cavity (i.e., clinoid, sphenoid wing, tuberculum sellae, diaphragma sellae) were excluded. Diagnosis was based on ophthalmological, radiological, and intraoperative findings, which were confirmed by the typical histological findings. Preoperative, postoperative, and follow-up visual assessments were performed by neuro-ophthalmologists in all cases., Results: The patients included 7 females and 1 male. The mean age at diagnosis was 45.1 years (range 25.0-70.0 years). Mean duration of follow-up was 38.9 months (range 3.0-88.0 months). All patients reported visual complaints, and all had objective evidence of optic nerve dysfunction. Their evaluation included visual field, visual acuity, funduscopy, and retinal fiber thickness. Total resection was obtained in 4 cases. Comparing preoperative and postoperative visual function revealed that 4 patients had improvement at the last follow-up, 1 patient had stable vision, and 3 patients had decreased function but none had total vision loss. All patients with good preoperative visual acuity maintained this status following surgical treatment. There was no surgical mortality or infection. Operative complications included binocular diplopia in 4 patients, which remitted spontaneously., Conclusions: Surgery can play a beneficial role in the primary treatment of ONSM, especially lesions located in the posterior third of the nerve. Total removal can be achieved with vision preservation or improvement, without major surgical complications, especially at early stages of the disease. Patients with good preoperative vision and CSF flow in the optic sheath have better chances of a favorable outcome than those with poor vision.

Optic nerve sheath meningiomas (ONSM) and intra-conal orbital lymphomas are common entities on the differential of a retrobulbar optic nerve involving space-occupying lesion. In this study, we compare the pre-surgical diagnosis, based on clinical presentation and neuroimaging, to the surgical pathology results of intra-conal orbital lymphomas and ONSM. This is an IRB approved retrospective chart review of orbital lymphomas and optic nerve sheath meningiomas biopsied by a single surgeon over a 4-year period at a single institution. Pre-surgical diagnosis and surgical pathology were compared. Fifteen cases of orbital lymphoma were identified. Fourteen were excluded based on extra-conal location. The single histologically confirmed intra-conal orbital lymphoma had a pre-surgical diagnosis of ONSM. Four cases of optic nerve sheath meningioma were identified. Three of the 4 cases of histologically confirmed ONSM had a pre-surgical diagnosis of ONSM. One of the 4 had a pre-surgical diagnosis of lymphoma. Diagnosis based on surgical pathology differed from the pre-surgical diagnosis in 2 out of 5 cases showing that clinical diagnosis does not always correlate with histologic diagnosis. Although both diseases are typically managed with radiation therapy, the treatment dosage and systemic disease implications are very different. These findings emphasis the importance of biopsy in the diagnosis of orbital lesions surrounding the optic nerve.

Meningiomas rarely cause CSF dissemination, and CSF seeding to the optic nerve (ON) is extremely rare. This is the first report of 2 cases of atypical meningioma with subacute visual loss due to ON seeding. The authors present the genetic characteristics of these atypical meningiomas with CSF dissemination. The patient in Case 1 was a 36-year-old woman with a 1.5-cm mass within the left ON, and the patient in Case 2 was a 70-year-old woman with a 0.9-cm mass around the right ON. Both individuals had undergone multiple surgeries for primary lesions and local recurrent lesions. They presented with subacute visual loss, and both tumors were completely resected. The pathological diagnosis was atypical meningioma with high MIB-1 indices and p53-positive cell ratios in each case. Comparative genomic hybridization showed significant chromosomal copy number alterations similar to the results of previous surgeries, confirming that the tumors were disseminated lesions. The present findings suggest that genetic characteristics, such as 1p and 10qcen-23 losses and 17q and 20 gains, shared by the 2 cases might be associated with CSF dissemination of meningiomas.

A 36-year-old woman presented with progressive loss of vision in the left eye for 3 years, and rapid progression and painful protrusion of the eye for one month. Clinical evaluation revealed no light perception, severe proptosis and hypoglobus, optic atrophy, and optociliary shunt vessels. Orbital imaging showed a well-defined heterogeneous intraconal mass partially encasing the optic nerve. A clinical diagnosis of optic nerve sheath meningioma was made, and the tumor was completely excised along with enucleation, followed by postoperative adjuvant external beam radiotherapy. There was no local recurrence at 15 month follow-up. Histopathologically, the tumor was found to be arising from the optic nerve meninges with classical "stag-horn" pattern and abundant cellularity. Immunohistochemistry supported the histopathological diagnosis of hemangiopericytoma. Optic nerve meningeal hemangiopericytoma is extremely rare-only two such cases have been reported in the literature., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Meningiomas are the most common form of primary intracranial tumors. If the anterior visual pathways are affected clinical visual compromise, visual field defects, oculomotor nerve disturbances or propotosis are predominant. Meningiomas of the anterior visual pathway remain therapeutically challenging due to the direct anatomical relationship to the circulus arteriosus cerebri, the cavernous sinus and cranial nerves. The therapy of choice is microsurgical resection. In many cases a curative approach can be achieved with modern surgical techniques and simultaneously maintaining patient quality of life. Problematic are cases in which resection would be associated with the risk of clinical impairment and in these cases radiotherapy is an important therapeutic option. In cases involving complex invasiveness an interdisciplinary treatment to control local clinical symptoms is favored.

Introduction: Early diagnosis of tumors which compress the anterior optic apparatus is important in order to prevent visual functional damage. Pre-operative visual function is correlated with post operative visuaL results, therefore, delay in diagnosis leading to deterioration in vision may cause irreversible damage., Objectives: Reviewing our experience with 100 patients with meningiomas involving the optic apparatus and establishing guidelines for early imaging in patients with visual impairment to prevent delays in diagnosis., Methods: Data was retrospectively collected for 100 patients with a meningioma involving the anterior optic apparatus, who underwent surgery between the years 2003-2011. Data was collected from hospital inpatient and outpatient files, as well as eye exams from the outset of the patient's symptoms and other exams that were carried out in the community., Results: In 14 patients there was a delay of one year or more in the diagnosis of meningioma. Of these, 3 were initially diagnosed with glaucoma, 3 with cataracts, 2 with migraines, in 5 patients no further investigation was conducted in spite of their ongoing complaints and in 1 patient, brain imaging was reported as normal., Conclusions: In a distinct number of patients there was a delay in diagnosis of over a year. A patient with complaints of deterioration in visual acuity which is not corrected by glasses, with examination findings of an afferent pupil and visual field defects, should undergo neuro-imaging in order to rule out a space-occupying lesion. This should be the case even if the patient has findings of a cataract which may partially explain deterioration in visual acuity.

Meningiomas are the most common non-malignant tumours of the brain. Gross-total resection remains the preferred treatment, if achievable without morbidity. Radiation therapy is advocated for inoperable, incompletely resected, or recurrent grade 1 tumours, if there is a progressive, symptomatic lesion, or in case of functional impairment. Postoperative radiation therapy is recommended for grade 2 or 3 lesions. Fractionated stereotactic radiotherapy and stereotactic radiosurgery are high precision techniques, allowing good sparing of surrounding tissues. Fractionated stereotactic radiotherapy and stereotactic radiosurgery give comparable results, with excellent 5-year tumour control rates of more than 90% for benign meningiomas. Toxicity is low and seems equivalent, despite a biased use of fractionated stereotactic radiotherapy for larger meningiomas, close to critical structures. Fractionated stereotactic radiotherapy seems to be of special interest in the treatment of cavernous sinus or optic pathways meningiomas. The different therapeutic modalities should be discussed by a multidisciplinary team., (Copyright © 2012 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.)

Purpose: To evaluate the effectiveness of fractionated stereotactic radiotherapy (SFRT) in the treatment of optic nerve sheath meningioma (ONSM)., Methods and Materials: Between 1993 and 2005, 109 patients (113 eyes) with primary (n = 37) or secondary (n = 76) ONSM were treated according to a prospective protocol with SFRT to a median dose of 54 Gy. All patients underwent radiographic, ophthalmologic, and endocrine analysis before and after SFRT. Radiographic response, visual control, and late side effects were endpoints of the analysis., Results: Median time to last clinical, radiographic, and ophthalmologic follow up was 30.2 months (n = 113), 42.7 months (n = 108), and 53.7 months (n = 91), respectively. Regression of the tumor was observed in 5 eyes and progression in 4 eyes, whereas 104 remained stable. Visual acuity improved in 12, deteriorated in 11, and remained stable in 68 eyes. Mean visual field defects reduced from 33.6% (n = 90) to 17.8% (n = 56) in ipsilateral and from 10% (n = 94) to 6.7% (n = 62) in contralateral eyes. Ocular motility improved in 23, remained stable in 65, and deteriorated in 3 eyes. Radiographic tumor control was 100% at 3 years and 98% at 5 years. Visual acuity was preserved in 94.8% after 3 years and in 90.9% after 5 years. Endocrine function was normal in 90.8% after 3 years and in 81.3% after 5 years., Conclusions: SFRT represents a highly effective treatment for ONSM. Interdisciplinary counseling of the patients is recommended. Because of the high rate of preservation of visual acuity we consider SFRT the standard approach for the treatment of ONSM. Prolonged observation is warranted to more accurately assess late visual impairment. Moderate de-escalation of the radiation dose might improve the preservation of visual acuity and pituitary gland function., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Background: Traditional treatment options for optic nerve sheath meningiomas (ONSMs) include observation, surgery, and radiotherapy, but to date none of these has become the clear treatment of choice., Objective: To evaluate the effectiveness and safety of multisession radiosurgery for ONSMs., Methods: From May 2004 to June 2008, 21 patients with ONSMs were treated by radiosurgery using the frameless CyberKnife system. Patient age ranged from 36 to 73 years (mean, 54 years). All patients were treated using multisession radiosurgery, with 5 fractions of 5 Gy each to a total dose of 25 Gy prescribed to the 75% to 85% isodose line. Patients were evaluated for tumor growth control and visual function., Results: The median pretreatment tumor volume was 2.8 mL (range, 0.3-23 mL). The mean follow-up was 30 months (range, 11-68 months). All patients tolerated treatment well, with only 1 patient in whom a mild optic neuropathy developed (which remitted after systemic steroid therapy). No other acute or late radiation-induced toxicities were observed. No patients showed ONSM progression on follow-up magnetic resonance imaging. Two patients (10%) had a partial response. No patients had worsening of visual function; visual function was stable in 65% and improved in 35% of patients., Conclusion: Multisession radiosurgery for ONSMs was found to be safe and effective. The preliminary results from this study, in terms of growth control, visual function improvement, and toxicity, are quite promising. Further investigations are warranted.

Purpose: We analyzed our long-term experience with fractionated stereotactic radiotherapy (FSRT) in patients with meningioma of the optic nerve sheath (ONSM)., Patients and Methods: Between January 1991 and January 2010, 40 patients with ONSM were treated using FSRT. Of these, 19 patients received radiotherapy as primary treatment, and 21 patients were treated after surgical resection. The median target volume was 9.2 ml, median total dose was 54 Gy in median single fractions of 1,8 Gy., Results: Local progression-free survival was 100%. Median survival after FSRT was 60 months (range 4-228 months). In all patients overall toleration of FSRT was very good. Acute toxicity was mild. Prior to RT, 29 patients complained about any kind of visual impairment including visual field deficits, diplopia or amaurosis. Prior surgical resection was identified as a negative prognostic factor for visual outcome, whereas patients with larger tumor volumes demonstrated a higher number of patients with improvement of pre-existing visual deficits., Conclusion: Long-term outcome after FSRT for ONSM shows improved vision in patients not treated surgically prior to RT; moreover, the best improvement of visual deficits are observed in patients with larger target volumes. The absence of tumor recurrences supports that FSRT is a strong alternative to surgical resection especially in small tumors without extensive compression of normal tissue structures.

Objective: Optic nerve sheath meningiomas (ONSMs) represent the most challenging lesions involving the optic pathways: Microsurgery is not indicated and classical single-stage radiosurgery appears to be too risky due to the expected destruction of the common blood supply with consequent loss of vision. Staged radiosurgery might be one treatment option because it exploits the ability of normal tissues to repair sub-lethal radiation-induced damage, offering a chance to control tumor growth while sparing function. Staged robotic radiosurgery was offered to 5 patients harboring ONSMs with the aim of sparing vision while achieving local growth control., Patients and Methods: Five patients with ONSM presenting with visual field deficits and loss of visual acuity were treated with staged CyberKnife radiosurgery, receiving 20 Gy in 4 stages (5 Gy per stage). Treatment planning was based on contrast-enhanced thin-slice CT (1.25 mm thickness for the first three cases, 0.5 mm for the last two) and volumetric MR imaging (1.5 T for the first three cases, 3 T for the last two). An interval of 24 hours was strictly observed between stages. Visual acuity and visual fields were assessed in all patients immediately prior to treatment and at intervals of 6 months thereafter. Follow-up MRIs were performed every 6 months for 2 years, then once per year., Results: The entire procedure, inclusive of imaging, treatment planning and treatment delivery, was performed in 5 days. Irradiation required approximately 45 min per stage. Mean tumor volume was 2.94 cc (range: 0.8-6.4 cc). Treatment was well tolerated in all patients. Follow-up ranged from 36 to 74 months. Local growth control was achieved in all patients. Restoration of normal vision was experienced by 4 patients 6 to 12 months after the treatment. One patient, who was also affected by diabetic retinopathy, showed a modest improvement after 6 months, remaining stable thereafter., Conclusion: Staged CyberKnife radiosurgery provides a fast and well-tolerated non-invasive treatment with excellent visual outcomes. If these preliminary results are confirmed by larger series, staged radiosurgery could be proposed as a first-line treatment for ONSM.

Object: The goal of this study was to assess the long-term results of Gamma Knife surgery (GKS) in patients harboring an optic nerve sheath meningioma (ONSM)., Methods: Thirty patients harboring an ONSM were treated with GKS between 1998 and 2003. Gamma Knife surgery was performed as the sole treatment option in 21 of these patients and resection had been performed previously in 9 patients. The mean volume of the tumor at the time of GKS was 3.6 cm(3) (range 1.4-9.7 cm(3)), and the mean prescription peripheral dose was 13.3 Gy (range 10-17 Gy). The mean number of isocenters used to treat these lesions was 8 (range 5-14 isocenters)., Results: At a median follow-up of 56 months, visual acuity improved in 11 patients, remained stable in 13 patients (including 4 patients who were completely blind before GKS), and deteriorated in 6 patients. Follow-up images were available in all patients and showed tumor regression in 20 patients and stable tumor in 8 patients. Persistent imaging evidence of progression was only present in 2 patients. With the exception of reversible conjunctival edema in 4 cases, no other serious acute side effect was observed., Conclusions: Gamma Knife surgery provides long-term tumor control for ONSM. The results of this study add substantial evidence that GKS may definitely become a standard treatment approach in selected cases of ONSM.

Intraoperative visual system monitoring of lesions with a close relationship to the optic apparatus by using light flashes reportedly is difficult to perform, and the results are too unreliable to interpret. The authors used direct epidural electrical stimulation of the optic nerve (ON) during surgery instead of light flashes. Four patients were included in this feasibility study. In 3 patients-1 each harboring a planum sphenoidale meningioma, a tuberculum sellae meningioma, and an intraorbital ON sheath meningioma-2 stimulating needle electrodes were placed on each side of the ON just anterior to the optic canal, before unroofing the optic canal and an extradural anterior clinoidectomy. In the fourth patient, who harbored a frontotemporal astrocytoma, stimulation was applied at the exit of the ON from the canal. The electrically induced visual evoked potentials (eVEPs) were recorded from the scalp before, during, and after tumor removal. A typical eVEP consisted of N20 and N40 waves. The amplitude of the N40 wave varied up to 25% prior to tumor removal. In the patient with a symptomatic tuberculum sellae meningioma, the decompressive effect of opening the optic canal and the impact of manipulation during piecemeal tumor removal were detected by the eVEPs. In the patient with an ON sheath meningioma and light sensation, only the N20 wave was observed. Epidural electrical stimulation of the ON is a safe means of providing a stable signal and real-time information on nerve conduction during surgery. It may be a useful adjunct in improving visual outcomes postoperatively. Further clinical studies are necessary.

A 28-year-old man with a biopsy-proven benign intraorbital optic nerve sheath meningioma developed recurrent clinical manifestations of ipsilateral retrobulbar inflammation 9 years after undergoing postoperative radiation therapy. Debulking of the tumor 11 years after the original surgery again revealed no pathologic signs of inflammation. Whether growth of tumor, surgery, radiation, or edema triggered the inflammatory manifestations is unclear. Our case affirms that primary optic nerve meningiomas may rarely cause episodic manifestations resembling those of idiopathic orbital inflammation that resolve with corticosteroid treatment.

Optic nerve sheath meningiomas (ONSMs) are benign lesions originating from the dural sheath of the optic nerve. Progressive growth can lead to gradual loss of vision and exophthalmos. Loss of vision following microsurgical resection is not uncommon, and although stereotactic fractionated radiotherapy can be a safe alternative to control tumor growth and preserve vision, it may also lead to complications. Frame-based stereotactic radiosurgery has only been rarely used because single-fraction high-dose treatments of intrinsic optic nerve lesions may induce unacceptably high toxicity. New frameless radiosurgery devices such as the robotic CyberKnife, an image-guided radiosurgery system, can provide the extremely tight conformality and submillimetric accuracy of frame-based systems combined with the possibility of delivering radiation in several sessions. In the present report the authors review the clinical presentation and management of ONSMs and describe their preliminary experience using multisession radiosurgery to treat these lesions.

Objective: To evaluate results of stereotactic radiotherapy for the treatment of optic nerve sheath meningioma (OM) at Ramathibodi Hospital., Material and Method: Twelve patients with primary OM were treated with stereotactic radiation between 1998 and 2005. Five patients underwent surgery and had no light perception before radiation. All patients except one were treated with fractionated stereotactic radiotherapy (FSRT). Mean average dose of FSRT was 55. 7 Gy; 180 cGy/fraction. One patient was treated with 15-Gy stereotactic radiosurgery., Results: With a median follow-up of 34 months, there was no visual improvement in the five patients who were completely blind before radiation. Visual acuity improved in four patients and remained stable in two patients. Four of six patients had improved visual field, and five of six decreased in proptosis. Follow-up images were available in six patients, showing minimal tumor regression in five and stable in one. No serious acute side effect was observed. Vision became worse in one patient, who developed vitreous hemorrhage two years after FSRT., Conclusion: Stereotactic radiotherapy is an effective treatment for primary OM. It provides tumor control and visual preservation with low risk of complications. However more patients and further follow-up are needed for long-term outcomes.

Tumors involving the optic nerve (optic glioma, optic nerve sheath meningioma) are benign but difficult to treat. Gamma knife surgery (GKS) may be a useful treatment. The authors present data obtained in three such cases and record the effects of GKS.

Objective: Surgical strategies and results for 50 patients with meningiomas involving the optic nerves are discussed and evaluated. Factors affecting the degree of resection and patient outcomes are presented. We emphasize our surgical techniques for resection of these tumors and we discuss the advantages of different approaches, depending on the relationship of the tumor to the optic nerves., Methods: Data for 50 patients with meningiomas involving the optic nerves who were surgically treated between 1991 and 2002 were reviewed, by using patient files, operative notes, and pre- and postoperative imaging and ophthalmological examination findings., Results: Thirty-one female patients and 19 male patients, with a mean age of 53 years, were treated. Thirty-one patients (62%) underwent complete tumor removal (Simpson Grade 1 or 2), and 19 patients underwent subtotal removal (Grade 4). Factors affecting the grade of resection were tumor size (P = 0.01), location (P = 0.007), and internal carotid artery encasement (P = 0.019). Patients who underwent Grade 1 or 2 resection exhibited a mean tumor size of 3.0 cm, and patients who underwent Grade 4 resection exhibited a mean tumor size of 4.1 cm. Only three patients had residual tumor on the optic nerve; all others had tumor in the cavernous sinus or at the orbital apex or exhibited vascular involvement. Visual outcomes were influenced predominantly by tumor size, preoperative visual function, and optic nerve encasement., Conclusion: Meningiomas that involve the optic nerves require special considerations and surgical techniques. Early decompression of the optic nerve within the bony canal allows identification and separation of the tumor from the nerve, permitting removal of the tumor from this area with minimal manipulation of the optic nerve.

Optic nerve sheath meningiomas (ONSMs) represent 1 to 2% of all meningiomas and one third of all optic nerve tumors. The management of ONSMs is controversial. Traditional surgical removal often results in postoperative blindness in the affected eye and thus has been abandoned as a treatment option in most patients. Surgery may be unnecessarily aggressive, especially if the patient has useful vision. When these tumors are left untreated, however, ensuing progressive visual impairment may lead to complete blindness. More recently, radiotherapy has gained wider acceptance as a treatment for these lesions. The authors of some reports have suggested that fractionated stereotactic radiosurgery (SRS) may be the best option for treating primary ONSMs. In patients with documented progressive visual deterioration, fractionated SRS may be effective in improving or stabilizing remaining functional vision. The authors review the clinical presentation, radiographic characteristics, and management of ONSMs, emphasizing the use of fractionated SRS.

We performed stereotactic radiosurgery on a patient with a presumed optic nerve sheath meningioma with a progressive optic neuropathy and an intact peripheral visual field. The patient's visual acuity and visual field have remained stable for 2 years following treatment, and the appearance of the tumor has not changed by neuroimaging. We believe that stereotactic radiosurgery is a viable option for treating optic nerve sheath meningioma.