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OBJECTIVE There is a reported elevated risk of cerebral aneurysms in patients with intracranial dural arteriovenous fistulas (dAVFs). However, the natural history, rate of spontaneous regression, and ideal treatment regimen are not well characterized. In this study, the authors aimed to describe the characteristics of patients with dAVFs and intracranial aneurysms and propose a classification system. METHODS The Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR) database from 12 centers was retrospectively reviewed. Analysis was performed to compare dAVF patients with (dAVF+ cohort) and without (dAVF-only cohort) concomitant aneurysm. Aneurysms were categorized based on location as a dAVF flow-related aneurysm (FRA) or a dAVF non–flow-related aneurysm (NFRA), with further classification as extra- or intradural. Patients with traumatic pseudoaneurysms or aneurysms with associated arteriovenous malformations were excluded from the analysis. Patient demographics, dAVF anatomical information, aneurysm information, and follow-up data were collected. RESULTS Of the 1077 patients, 1043 were eligible for inclusion, comprising 978 (93.8%) and 65 (6.2%) in the dAVF-only and dAVF+ cohorts, respectively. There were 96 aneurysms in the dAVF+ cohort; 10 patients (1%) harbored 12 FRAs, and 55 patients (5.3%) harbored 84 NFRAs. Dural AVF+ patients had higher rates of smoking (59.3% vs 35.2%, p < 0.001) and illicit drug use (5.8% vs 1.5%, p = 0.02). Sixteen dAVF+ patients (24.6%) presented with aneurysm rupture, which represented 16.7% of the total aneurysms. One patient (1.5%) had aneurysm rupture during follow-up. Patients with dAVF+ were more likely to have a dAVF located in nonconventional locations, less likely to have arterial supply to the dAVF from external carotid artery branches, and more likely to have supply from pial branches. Rates of cortical venous drainage and Borden type distributions were comparable between cohorts. A minority (12.5%) of aneurysms were FRAs. The majority of the aneurysms underwent treatment via either endovascular (36.5%) or microsurgical (15.6%) technique. A small proportion of aneurysms managed conservatively either with or without dAVF treatment spontaneously regressed (6.2%). CONCLUSIONS Patients with dAVF have a similar risk of harboring a concomitant intracranial aneurysm unrelated to the dAVF (5.3%) compared with the general population (approximately 2%–5%) and a rare risk (0.9%) of harboring an FRA. Only 50% of FRAs are intradural. Dural AVF+ patients have differences in dAVF angioarchitecture. A subset of dAVF+ patients harbor FRAs that may regress after dAVF treatment.

Objective To discuss optimal treatment strategy for spindle cell oncocytoma (SCO) of the pituitary gland. Methods Institutional cases were retrospectively reviewed. A systematic literature search and subsequent quantitative synthesis were performed for further analysis. The detailed features were summarized and the tumor control rate (TCR) was calculated. Results Eighty-five patients (6 institutional and 79 literature) were included. The annual incidence was approximately 0.01–0.03/100,000. The mean age was 56 years. Vision loss was present in 60%. Seventy-three percent showed hormonal abnormalities. On magnetic resonance imaging, tumor was avidly enhancing, and the normal gland was commonly displaced anterosuperiorly. Evidence of hypervascularity was seen in 77%. Gross total resection (GTR) was achieved in only 24% because of its hypervascular, fibrous, and adhesive nature. The mean postoperative follow-up was 3.3 years for institutional cases and 2.3 years for the integrated cohort. The TCR was significantly better after GTR (5-year TCR, 75%; P = 0.012) and marginally better after non-GTR + upfront radiotherapy (5-year TCR, 76%; P = 0.103) than after non-GTR alone (5-year TCR, 24%). The TCRs for those with low Ki-67 index (≤5%) were marginally better than those with higher Ki-67 index (5-year rate, 57% vs. 23%; P = 0.110). Conclusions Frequent endocrine-related symptoms, hypervascular signs, and anterosuperior displacement of the gland support preoperative diagnosis of SCO. GTR seems to have better long-term tumor control, whereas the fibrous, hypervascular, and adhesive nature of SCO makes it difficult to achieve GTR. In patients with non-GTR, radiotherapy may help decrease tumor progression.

To clarify the need for post-operative radiation treatment in skull base chondrosarcomas (SBCs). A retrospective analysis of patients with grade I or II SBC. Patients were divided according to post-surgical treatment strategies: (A) planned upfront radiotherapy and (B) watchful waiting. Tumor control and survival were compared between the treatment groups. The median follow-up after resection was 105 months (range, 9–376). Thirty-two patients (Grade 1, n = 16; Grade 2, n = 16) were included. The most frequent location was petroclival (21, 64%). A gross total resection (GTR) was achieved in 11 patients (34%). Fourteen (44%) underwent upfront radiotherapy (group A) whereas 18 (56%) were followed with serial MRI alone (group B). The tumor control rate for the entire group was 77% and 69% at 10- and 15-year, respectively. Upfront radiotherapy (P = 0.25), extent of resection (P = 0.11) or tumor grade (P = 0.83) did not affect tumor control. The majority of Group B patients with recurrent tumors (5/7) obtained tumor control with repeat resection (n = 2), salvage radiotherapy (n = 2), or a combination of both (n = 1). The 10-year disease-specific survival was 95% with no difference between the group A and B (P = 0.50). For patients with grade I/II SBC, a reasonable strategy is deferral of radiotherapy after maximum safe resection until tumor progression or recurrence. At that time, most patients can be successfully managed with salvage radiotherapy or surgery. Late recurrences may occur, and life-long follow-up is advisable.

Introduction: Supratentorial primitive neuroectodermal tumor is a rare, aggressive intrinsic brain tumor with limited treatment options for recurrent disease. SRS as a treatment modality in the recurrent setting was investigated. Methods: A retrospective review of 8 patients treated with SRS for local or distant recurrence of supratentorial PNET from 1999 to 2014 was conducted. Results: Thirty-six tumors were treated in 15 sessions in 8 patients. The median patient age was 22.5 (interquartile range [IQR], 14.75–43.5 years) with a median 21-month period from diagnosis until SRS (IQR, 16–23.75 months). The median prescription isodose volume was 1.85 cm3 (IQR, 1.85–7.02 cm3); median tumor margin dose was 18 Gy (IQR 14–20 Gy); and median isocenters was 2 (range 1–13). No patients experienced adverse radiation effects. All but 1 patient died, and the median overall survival was 32 months (IQR, 26.75–53.5 months) with median overall survival following SRS of 9.5 months (IQR, 5.25–30 months). Univariate analysis failed to demonstrate a statistically significant association between age, number of gamma knife treatments, interval to gamma knife, and margin radiation dose with overall survival. Discussion/Conclusion: This series supports the use of SRS in patients with recurrent supratentorial PNET following multimodal therapy.

OBJECTIVE Cranial dural arteriovenous fistulas (dAVFs) are often treated with endovascular therapy, but occasionally a multimodality approach including surgery and/or radiosurgery is utilized. Recurrence after an initial angiographic cure has been reported, with estimated rates ranging from 2% to 14.3%, but few risk factors have been identified. The objective of this study was to identify risk factors associated with recurrence of dAVF after putative cure. METHODS The Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR) data were retrospectively reviewed. All patients with angiographic cure after treatment and subsequent angiographic follow-up were included. The primary outcome was recurrence, with risk factor analysis. Secondary outcomes included clinical outcomes, morbidity, and mortality associated with recurrence. Risk factor analysis was performed comparing the group of patients who experienced recurrence with those with durable cure (regardless of multiple recurrences). Time-to-event analysis was performed using all collective recurrence events (multiple per patients in some cases). RESULTS Of the 1077 patients included in the primary CONDOR data set, 457 met inclusion criteria. A total of 32 patients (7%) experienced 34 events of recurrence at a mean of 368.7 days (median 192 days). The recurrence rate was 4.5% overall. Kaplan-Meier analysis predicted long-term recurrence rates approaching 11% at 3 years. Grade III dAVFs treated with endovascular therapy were statistically significantly more likely to experience recurrence than those treated surgically (13.3% vs 0%, p = 0.0001). Tentorial location, cortical venous drainage, and deep cerebral venous drainage were all risk factors for recurrence. Endovascular intervention and radiosurgery were associated with recurrence. Six recurrences were symptomatic, including 2 with hemorrhage, 3 with nonhemorrhagic neurological deficit, and 1 with progressive flow-related symptoms (decreased vision). CONCLUSIONS Recurrence of dAVFs after putative cure can occur after endovascular treatment. Risk factors include tentorial location, cortical venous drainage, and deep cerebral drainage. Multimodality therapy can be used to achieve cure after recurrence. A delayed long-term angiographic evaluation (at least 1 year from cure) may be warranted, especially in cases with risk factors for recurrence.

OBJECTIVE Cranial dural arteriovenous fistulas (dAVFs) are rare lesions, hampering efforts to understand them and improve their care. To address this challenge, investigators with an established record of dAVF investigation formed an international, multicenter consortium aimed at better elucidating dAVF pathophysiology, imaging characteristics, natural history, and patient outcomes. This report describes the design of the Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR) and includes characterization of the 1077-patient cohort. METHODS Potential collaborators with established interest in the field were identified via systematic review of the literature. To ensure uniformity of data collection, a quality control process was instituted. Data were retrospectively obtained. RESULTS CONDOR comprises 14 centers in the United States, the United Kingdom, the Netherlands, and Japan that have pooled their data from 1077 dAVF patients seen between 1990 and 2017. The cohort includes 359 patients (33%) with Borden type I dAVFs, 175 (16%) with Borden type II fistulas, and 529 (49%) with Borden type III fistulas. Overall, 852 patients (79%) presented with fistula-related symptoms: 427 (40%) presented with nonaggressive symptoms such as tinnitus or orbital phenomena, 258 (24%) presented with intracranial hemorrhage, and 167 (16%) presented with nonhemorrhagic neurological deficits. A smaller proportion (224 patients, 21%), whose dAVFs were discovered incidentally, were asymptomatic. Many patients (85%, 911/1077) underwent treatment via endovascular embolization (55%, 587/1077), surgery (10%, 103/1077), radiosurgery (3%, 36/1077), or multimodal therapy (17%, 184/1077). The overall angiographic cure rate was 83% (758/911 treated), and treatment-related permanent neurological morbidity was 2% (27/1467 total procedures). The median time from diagnosis to follow-up was 380 days (IQR 120–1038.5 days). CONCLUSIONS With more than 1000 patients, the CONDOR registry represents the largest registry of cranial dAVF patient data in the world. These unique, well-annotated data will enable multiple future analyses to be performed to better understand dAVFs and their management.

OBJECTIVE Current evidence suggests that intracranial dural arteriovenous fistulas (dAVFs) without cortical venous drainage (CVD) have a benign clinical course. However, no large study has evaluated the safety and efficacy of current treatments and their impact over the natural history of dAVFs without CVD. METHODS The authors conducted an analysis of the retrospectively collected multicenter Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR) database. Patient demographics and presenting symptoms, angiographic features of the dAVFs, and treatment outcomes of patients with Borden type I dAVFs were reviewed. Clinical and radiological follow-up information was assessed to determine rates of new intracranial hemorrhage (ICH) or nonhemorrhagic neurological deficit (NHND), worsening of venous hyperdynamic symptoms (VHSs), angiographic recurrence, and progression or spontaneous regression of dAVFs over time. RESULTS A total of 342 patients/Borden type I dAVFs were identified. The mean patient age was 58.1 ± 15.6 years, and 62% were women. The mean follow-up time was 37.7 ± 54.3 months. Of 230 (67.3%) treated dAVFs, 178 (77%) underwent mainly endovascular embolization, 11 (4.7%) radiosurgery alone, and 4 (1.7%) open surgery as the primary modality. After the first embolization, most dAVFs (47.2%) achieved only partial reduction in early venous filling. Multiple complementary interventions increased complete obliteration rates from 37.9% after first embolization to 46.7% after two or more embolizations, and 55.2% after combined radiosurgery and open surgery. Immediate postprocedural complications occurred in 35 dAVFs (15.2%) and 6 (2.6%) with permanent sequelae. Of 127 completely obliterated dAVFs by any therapeutic modality, 2 (1.6%) showed angiographic recurrence/recanalization at a mean of 34.2 months after treatment. Progression to Borden-Shucart type II or III was documented in 2.2% of patients and subsequent development of a new dAVF in 1.6%. Partial spontaneous regression was found in 22 (21.4%) of 103 nontreated dAVFs. Multivariate Cox regression analysis demonstrated that older age, NHND, or severe venous-hyperdynamic symptoms at presentation and infratentorial location were associated with worse prognosis. Kaplan-Meier curves showed no significant difference for stable/improved symptoms survival probability in treated versus nontreated dAVFs. However, estimated survival times showed better trends for treated dAVFs compared with nontreated dAVFs (288.1 months vs 151.1 months, log-rank p = 0.28). This difference was statistically significant for treated dAVFs with 100% occlusion (394 months, log-rank p < 0.001). CONCLUSIONS Current therapeutic modalities for management of dAVFs without CVD may provide better symptom control when complete angiographic occlusion is achieved.

Background Ewing-like sarcoma with capicua transcriptional repressor (CIC) rearrangement is a unique class of undifferentiated round cell sarcomas characterized by CIC–double homeobox 4 gene fusion. Despite showing great histologic resemblance to Ewing sarcomas, they have proved to be a distinct pathological entity from the immunohistochemistry and genetic examinations and the response to treatment. We have presented a case of CIC-rearranged Ewing-like sarcoma with cerebral metastasis managed with operative resection and gamma knife radiosurgery. Case Description A 56-year-old woman had initially presented with an ulcerating lesion of the right fifth toe. The histological and immunohistochemical analysis revealed features consistent with CIC-rearranged Ewing-like sarcoma, which was confirmed with genetic analysis. Despite aggressive local control and a multidrug chemotherapy regimen, the patient developed multifocal metastases involving the lungs, femur, and cerebrum. The cerebral lesions were managed with surgery and gamma knife radiosurgery, with mixed results. Conclusion CIC-rearranged Ewing-like sarcomas have recently been recognized as a distinct disease entity with a highly aggressive course. Treatment paradigms have yet to be defined to properly manage such an aggressive pathological process.

BACKGROUND Stereotactic radiosurgery (SRS) is a safe and effective treatment for acromegaly. OBJECTIVE To improve understanding of clinical and dosimetric factors predicting biochemical remission. METHODS A single-institution cohort study of nonsyndromic, radiation-naive patients with growth hormone-producing pituitary adenomas (GHA) having single-fraction SRS between 1990 and 2017. Exclusions were treatment with pituitary suppressive medications at the time of SRS, or

Author(s): Graffeo, Christopher S; Sahgal, Arjun; De Salles, Antonio; Fariselli, Laura; Levivier, Marc; Ma, Lijun; Paddick, Ian; Regis, Jean Marie; Sheehan, Jason; Suh, John; Yomo, Shoji; Pollock, Bruce E | Abstract: BackgroundNo guidelines have been published regarding stereotactic radiosurgery (SRS) in the management of Spetzler-Martin grade I and II arteriovenous malformations (AVMs).ObjectiveTo establish SRS practice guidelines for grade I-II AVMs on the basis of a systematic literature review.MethodsPreferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-compliant search of Medline, Embase, and Scopus, 1986-2018, for publications reporting post-SRS outcomes in ≥10 grade I-II AVMs with a follow-up of ≥24 mo. Primary endpoints were obliteration and hemorrhage; secondary outcomes included Spetzler-Martin parameters, dosimetric variables, and "excellent" outcomes (defined as total obliteration without new post-SRS deficit).ResultsOf 447 abstracts screened, 8 were included (n = 1, level 2 evidence; n = 7, level 4 evidence), representing 1102 AVMs, of which 836 (76%) were grade II. Obliteration was achieved in 884 (80%) at a median of 37 mo; 66 hemorrhages (6%) occurred during a median follow-up of 68 mo. Total obliteration without hemorrhage was achieved in 78%. Of 836 grade II AVMs, Spetzler-Martin parameters were reported in 680: 377 were eloquent brain and 178 had deep venous drainage, totaling 555/680 (82%) high-risk SRS-treated grade II AVMs.ConclusionThe literature regarding SRS for grade I-II AVM is low quality, limiting interpretation. Cautiously, we observed that SRS appears to be a safe, effective treatment for grade I-II AVM and may be considered a front-line treatment, particularly for lesions in deep or eloquent locations. Preceding publications may be influenced by selection bias, with favorable AVMs undergoing resection, whereas those at increased risk of complications and nonobliteration are disproportionately referred for SRS.

Dural arteriovenous fistulas (dAVFs) are often treated with stereotactic radiosurgery (SRS) to achieve complete obliteration (CO), prevent future hemorrhages, and ameliorate neurological symptoms.To summarize outcomes after SRS for dAVFs and propose relevant practice recommendations.Using a PICOS/PRISMA/MOOSE protocol, we included patients with dAVFs treated with SRS and data for at least one of the outcomes of the study. Relevant outcomes were CO, symptom improvement and cure, and post-SRS hemorrhage or permanent neurological deficits (PNDs). Estimated outcome effect sizes were determined using weighted random-effects meta-analyses using DerSimonian and Laird methods. To assess potential relationships between patient and lesion characteristics and clinical outcomes, mixed-effects weighted regression models were used.Across 21 published studies, we identified 705 patients with 721 dAVFs treated with SRS. The CO rate was 68.6% (95% CI 60.7%-76.5%) with symptom improvement and cure rates of 97.2% (95% CI 93.2%-100%) and 78.8% (95% CI 69.3%-88.2%), respectively. Estimated incidences of post-SRS hemorrhage and PNDs were 1.1% (95% CI 0.6%-1.6%) and 1.3% (95% CI 0.8%-1.8%), respectively. Noncavernous sinus (NCS) dAVFs were associated with lower CO (P = .03) and symptom cure rates (P = .001). Higher grade was also associated with lower symptom cure rates (P = .04), whereas previous embolization was associated with higher symptom cure rates (P = .01).SRS for dAVFs results in CO in the majority of patients with excellent symptom improvement rates with minimal toxicity. Patients with NCS and/or higher-grade dAVFs have poorer symptom cure rates. Combined therapy with embolization and SRS is recommended when feasible for clinically aggressive dAVFs or those refractory to embolization to maximize the likelihood of symptom cure.

BACKGROUND Patients with persistent or recurrent Cushing disease (CD) after prior transsphenoidal surgery require further treatment to reduce the disease's metabolic consequences. OBJECTIVE To assess patient outcomes after stereotactic radiosurgery (SRS) for persistent or recurrent CD from adrenocorticotropin hormone (ACTH)-secreting pituitary adenomas and propose a management algorithm. METHODS Retrospective review of 38 patients without prior radiation treatment having SRS for ACTH-secreting pituitary adenomas from 1990 to 2015. Favorable outcome was defined as biochemical remission and tumor growth control. Patients were evaluated separately if they underwent bilateral adrenalectomy (Adx). RESULTS Twenty patients (53%) were treated with Adx and SRS (median margin dose, 25 Gy) and 18 patients (47%) received SRS alone (median margin dose, 22.5 Gy). Median follow-up after SRS was 76 mo. Of patients undergoing Adx, 18/20 (90%) had a favorable outcome. Two patients (10%) had tumor growth requiring additional treatment. A favorable outcome was achieved in 13/18 patients (72%) having SRS alone (median, 14 mo; interquartile range, 8-23). Five patients (28%) required additional treatment due to persistent hypercortisolemia (n = 4) or hypercortisolemia and tumor growth (n = 1). Favorable outcomes were more frequent in the Adx and SRS group at 1 yr (100% vs 33%; P

OBJECTIVE The risk-to-benefit profile of treating an unruptured high-grade dural arteriovenous fistula (dAVF) is not clearly defined. The aim of this multicenter retrospective cohort study was to compare the outcomes of different interventions with observation for unruptured high-grade dAVFs. METHODS The authors retrospectively reviewed dAVF patients from 12 institutions participating in the Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR). Patients with unruptured high-grade (Borden type II or III) dAVFs were included and categorized into four groups (observation, embolization, surgery, and stereotactic radiosurgery [SRS]) based on the initial management. The primary outcome was defined as the modified Rankin Scale (mRS) score at final follow-up. Secondary outcomes were good outcome (mRS scores 0–2) at final follow-up, symptomatic improvement, all-cause mortality, and dAVF obliteration. The outcomes of each intervention group were compared against those of the observation group as a reference, with adjustment for differences in baseline characteristics. RESULTS The study included 415 dAVF patients, accounting for 29, 324, 43, and 19 in the observation, embolization, surgery, and SRS groups, respectively. The mean radiological and clinical follow-up durations were 21 and 25 months, respectively. Functional outcomes were similar for embolization, surgery, and SRS compared with observation. With observation as a reference, obliteration rates were higher after embolization (adjusted OR [aOR] 7.147, p = 0.010) and surgery (aOR 33.803, p < 0.001) and all-cause mortality was lower after embolization (imputed, aOR 0.171, p = 0.040). Hemorrhage rates per 1000 patient-years were 101 for observation versus 9, 22, and 0 for embolization (p = 0.022), surgery (p = 0.245), and SRS (p = 0.077), respectively. Nonhemorrhagic neurological deficit rates were similar between each intervention group versus observation. CONCLUSIONS Embolization and surgery for unruptured high-grade dAVFs afforded a greater likelihood of obliteration than did observation. Embolization also reduced the risk of death and dAVF-associated hemorrhage compared with conservative management over a modest follow-up period. These findings support embolization as the first-line treatment of choice for appropriately selected unruptured Borden type II and III dAVFs.

OBJECTIVEIntracranial facial nerve schwannomas (FNS) requiring treatment are frequently recommended for surgery or stereotactic radiosurgery (SRS). The objective of this study was to compare facial nerve function outcomes between these two interventions for FNS via a systematic review and meta-analysis.METHODSA search of the Ovid EMBASE, PubMed, SCOPUS, and Cochrane databases from inception to July 2019 was conducted following PRISMA guidelines. Articles were screened against prespecified criteria. Facial nerve outcomes were classified as improved, stabilized, or worsened by last follow-up. Incidence was pooled by random-effects meta-analysis of proportions.RESULTSThirty-three articles with a pooled cohort of 519 patients with FNS satisfied all criteria. Twenty-five articles described operative outcomes in 407 (78%) patients; 10 articles reported SRS outcomes in 112 (22%). In the surgical cohort, facial nerve function improved in 23% (95% CI 15%–32%), stabilized in 41% (95% CI 32%–50%), and worsened in 30% (95% CI 21%–40%). In the SRS cohort, facial nerve function was improved in 20% (95% CI 9%–34%), stable in 66% (95% CI 54%–78%), and worsened in 9% (95% CI 3%–16%). Compared with SRS, microsurgery was associated with a significantly lower incidence of stable facial nerve function (p < 0.01) and a significantly higher incidence of worsened facial nerve function (p < 0.01). Tumor progression and complication rates were comparable. Outcome certainty assessments were very low to moderate for all parameters.CONCLUSIONSUnfavorable facial nerve function outcomes are associated with surgical treatment of intracranial FNS, whereas stable facial nerve function outcomes are associated with SRS. Therefore, SRS should be recommended to patients with FNS who require treatment, and surgery should be reserved for patients with another indication, such as decompression of the brainstem. Further study is required to definitively optimize and validate management strategies for these rare skull base tumors.

Stereotactic radiosurgery (SRS) is commonly performed after surgical resection of brain metastases to reduce the chance of local tumor recurrence while maintaining cognitive function. Target delineation in these cases is typically based off T1-weighted post-gadolinium MRI (T1Gd). In this study, we report outcomes for patients having postoperative SRS in which the planning target volume (PTV) was based on T2-weighted MRI (T2W). Sixty-two consecutive patients having single-fraction SRS after brain metastases resection were retrospectively reviewed. Excluded were patients with prior whole brain radiation therapy, multiple resection cavities, and small cell pathologies. The median time from surgery to SRS was 11 days; 26 patients (42%) had SRS ≤ 7 days. The median PTV was 8.0 cm3; the median margin dose was 18 Gy. The crude rates of local tumor control (LC), leptomeningeal disease (LMD), distant brain recurrence (DBR), and radiation necrosis (RN) were 85%, 19%, 37%, and 2%, respectively. The 1-year LC, LMD, DBR, and RN rates were 88%, 25%, 36%, and 0%, respectively. No tumor or dosimetric factor was associated with LC. Sub-total tumor resection was a risk factor for LMD (HR 5.11, P = 0.003), whereas patients with multiple brain metastases had a greater risk of DBR (HR 2.88, P = 0.01). The median PTV was smaller compared to the median PTV based off the consensus guidelines utilizing T1Gd MRI (8.0 cm3 vs. 9.1 cm3, P = 0.004). T2W MRI provided accurate resection cavity delineation even in the early postoperative period and was associated with decreased PTV compared to T1Gd MRI in the majority of cases.

Background Stereotactic radiosurgery (SRS) is a commonly performed procedure for patients with intracranial meningiomas. Objective To describe the clinical features of patients with radiation-induced cavernous malformations (RICM) after single-fraction meningioma SRS. Methods Retrospective study of patients having single-fraction SRS for intracranial meningioma at our center from 1990 through 2009, and 1 patient who had single-fraction SRS elsewhere. Patients were excluded if they refused research authorization (n = 7), had a World Health Organization Grade II or III meningioma (n = 65), had a genetic predisposition for tumor development (n = 52), had prior or concurrent radiation therapy (n = 49), or had less than 2 yr of magnetic resonance imaging follow-up after SRS (n = 77). The median follow-up of the remaining 426 patients was 7.9 yr (range, 2-24.9). Results Three RICM (0.7%) were identified at 2, 10, and 21 yr after SRS. Two patients were asymptomatic, whereas 1 patient had a brainstem hemorrhage causing facial weakness and numbness. The risk of developing an RICM after SRS was 0.2% at 5 yr and 0.9% at 15 yr. All patients were observed and remained stable without additional bleeding in follow-up of 7, 12.8, and 2 yr, respectively. A fourth patient developed progressive neurological dysfunction starting 7 yr after SRS at another center and was treated for several years with bevacizumab without improvement. Surgical resection was performed 11.5 yr after SRS and histologic examination was consistent with an RICM. Conclusion The risk of RICM after single-fraction SRS for intracranial meningiomas is very low, but the latency period noted until their detection emphasizes the need for extended imaging follow-up after SRS of benign lesions.

To determine whether whole-brain radiation therapy (WBRT) is associated with improved overall survival among non-small cell lung cancer (NSCLC) patients with favorable prognoses at diagnosis.In the N0574 trial, patients with 1 to 3 brain metastases were randomized to receive stereotactic radiosurgery (SRS) or SRS plus WBRT (SRS + WBRT), with a primary endpoint of cognitive deterioration. We calculated diagnosis-specific graded prognostic assessment (DS-GPA) scores for NSCLC patients and evaluated overall survival according to receipt of WBRT and DS-GPA score using 2 separate cut-points (≥2.0 vs2.0 and ≥2.5 vs2.5).A total of 126 NSCLC patients were included for analysis, with median follow-up of 14.2 months. Data for DS-GPA calculation were available for 86.3% of all enrolled NSCLC patients. Overall, 50.0% of patients had DS-GPA score ≥2.0, and 23.0% of patients had DS-GPA scores ≥2.5. The SRS and SRS + WBRT groups were well balanced with regard to prognostic factors. The median survival according to receipt of WBRT was 11.3 months (+WBRT) and 17.9 months (-WBRT) for patients with DS-GPA ≥2.0 (favorable prognoses, P=.63; hazard ratio 0.86; 95% confidence interval 0.47-1.59). Median survival was 3.7 months (+WBRT) and 6.6 months (-WBRT) for patients with DS-GPA2.0 patients (unfavorable prognoses, P=.85; hazard ratio 0.95; 95% confidence interval 0.56-1.62). Outcomes according to the receipt of WBRT and DS-GPA remained similar utilizing DS-GPA ≥2.5 as a cutoff for favorable prognoses. There was no interaction between the continuum of the DS-GPA groups and WBRT on overall survival (P=.53).We observed no significant differences in survival according to receipt of WBRT in favorable-prognosis NSCLC patients. This study further supports the approach of SRS alone in the majority of patients with limited brain metastases.

Purpose To determine the risk of radiation-induced tumors or malignant transformation after single-fraction intracranial stereotactic radiosurgery (SRS). Methods and Materials We performed a retrospective review of 1837 patients who received single-fraction SRS for arteriovenous malformation or benign tumor (meningioma, vestibular schwannoma, pituitary adenoma, glomus tumor) at a single center between 1990 and 2009. Patients were excluded if they refused research authorization (n=31), had a genetic predisposition to tumor development (n=84), received prior or concurrent radiation therapy (n=79), or had less than 5 years of imaging follow-up after SRS (n=501). The median imaging follow-up period for the remaining 1142 patients was 9.0 years (range, 5-24.9 years). Results No radiation-induced tumors were identified in 11,264 patient-years of follow-up after SRS. The risk of a radiation-induced tumor developing after SRS was 0.0% at 5 years (95% confidence interval [CI], 0.0%-0.4%), 0.0% at 10 years (95% CI, 0.0%-0.9%), and 0.0% at 15 years (95% CI, 0.0%-2.8%). Malignant transformation occurred in 7 of 316 meningioma patients (2.2%) and 1 of 358 vestibular schwannoma patients (0.3%) at a median of 4.9 years (range, 2.8-13.8 years) after SRS. No cases of malignant transformation were noted in patients with pituitary adenomas (n=188) or glomus tumors (n=47). The 5-, 10-, and 15-year risk of malignant transformation was 0.5% (95% CI, 0.0%-0.9%), 0.8% (95% CI, 0.0%-1.8%), and 2.4% (95% CI, 0.0%-5.5%), respectively. Patients who underwent prior resection (hazard ratio, 14.56; 95% CI, 1.79-118.33; P =.01) and who had meningioma pathology (hazard ratio, 11.72; 95% CI, 1.44-96.15; P =.02) were at increased risk of malignant transformation. Conclusions The risk of radiation-induced tumors or malignant transformation after SRS is very low and should not be used as a justification for choosing alternative treatment approaches (surgical resection, observation) over SRS for appropriate patients.

BACKGROUND Late adverse radiation effects (ARE) typically occur many years after stereotactic radiosurgery (SRS) of intracranial arteriovenous malformations (AVM). They are characterized by perilesional edema or cyst formation and are distinct from radiation-induced changes (RIC) noted in the first 1 to 2 years after AVM SRS and radiation necrosis. OBJECTIVE To determine the incidence of late ARE after AVM SRS. METHODS Retrospective review of 233 AVM patients having SRS from 1990 to 2009. Patients had sporadic AVM, no prior radiation, and a minimum of 5 years of magnetic resonance imaging (MRI) follow-up. The median MRI follow-up after SRS was 9.8 years (range, 5-24.2). RESULTS Late ARE were observed in 16 patients (6.9%) at a median of 8.7 years after SRS (range, 2.0-16.1). The 5-, 10-, and 15-year incidence of late ARE was 0.4%, 7.7%, and 12.5%, respectively. Eight patients (3.4%) were symptomatic at the time of ARE detection. Three of 8 patients who were initially asymptomatic had documented cyst progression (at 11, 40, and 42 months), for an overall symptomatic rate of 4.7%. Five patients with asymptomatic ARE have been observed for a median of 9.3 years (range, 2.0-14.1) without progression. Patients having early RIC (hazard ratio [HR] = 2.11, P < .001), patients having obliteration (HR = 1.24, P = .02), and patients having SRS before April 1997 (HR = 1.12, P = .02) were more likely to develop late ARE. CONCLUSION Late ARE are common in AVM patients who develop early RIC after SRS. Resection of the thrombosed AVM and the adjacent damaged tissue is effective at eliminating the mass effect and improving patients' neurological condition.

OBJECTIVEThe goal of this study was to evaluate the outcomes of Gamma Knife stereotactic radiosurgery (SRS) when used for patients with intractable idiopathic glossopharyngeal neuralgia.METHODSSix participating centers of the International Gamma Knife Research Foundation identified 22 patients who underwent SRS for intractable glossopharyngeal neuralgia between 1998 and 2015. The median patient age was 60 years (range 34–83 years). The median duration of symptoms before SRS was 46 months (range 1–240 months). Three patients had unsuccessful prior surgical procedures, including microvascular decompression (MVD) (n = 2) and balloon compression (n = 1). The radiosurgical target was the glossopharyngeal meatus. The median maximum dose was 80 Gy.RESULTSThe median follow-up was 45 months after SRS (range 6–120 months). Twelve patients (55%) had < 4 years of follow-up. Thirteen patients (59%) had initial complete pain relief at a median of 12 days after SRS (range 1–60 days). Three patients (14%) had partial pain relief at a median of 70 days after SRS (range 60–90 days). Six patients (27%) had no pain relief. Among 16 patients with initial pain relief, 5 maintained complete pain relief without medication (Barrow Neurological Institute [BNI] pain intensity score Grade I), 1 maintained occasional pain relief without medication (BNI Grade II), 3 maintained complete pain relief with medication (BNI Grade IIIb), and 7 patients had pain recurrence at a median of 20 months after SRS (range 6–120 months). The rates of maintenance of adequate pain relief (BNI Grades I–IIIb) were 63% at 1 year, 49% at 2 years, 38% at 3 years, 38% at 5 years, and 28% at 7 years. When 7 patients without pain recurrence within 4 years of follow-up were excluded, the rates of maintenance of adequate pain relief were 38% at 5 years and 28% at 7 years. Ten patients required additional procedures (MVD, n = 4; repeat SRS, n = 5; glossopharyngeal nerve block, n = 1). Four of 5 patients who underwent repeat SRS maintained pain relief (BNI Grade I, n = 3; and BNI Grade IIIb, n = 1). No adverse effects of radiation were observed after a single SRS. Two patients developed hyperesthesia in the palatoglossal arch 5 and 8 months after repeat SRS, respectively.CONCLUSIONSStereotactic radiosurgery for intractable, medically refractory glossopharyngeal neuralgia provided lasting pain reduction in 55% of patients after 1 or 2 SRS procedures. Patients who had a poor response or pain recurrence may require additional procedures such as repeat SRS, MVD, nerve blocks, or nerve section. No patient developed changes in vocal cord function or swallowing disorders after SRS in this study.

Author(s): Marchetti, Marcello; Sahgal, Arjun; De Salles, Antonio AF; Levivier, Marc; Ma, Lijun; Paddick, Ian; Pollock, Bruce E; Regis, Jean; Sheehan, Jason; Suh, John H; Yomo, Shoji; Fariselli, Laura | Abstract: BackgroundStereotactic radiosurgery (SRS) for benign intracranial meningiomas is an established treatment.ObjectiveTo summarize the literature and provide evidence-based practice guidelines on behalf of the International Stereotactic Radiosurgery Society (ISRS).MethodsArticles in English specific to SRS for benign intracranial meningioma, published from January 1964 to April 2018, were systematically reviewed. Three electronic databases, PubMed, EMBASE, and the Cochrane Central Register, were searched.ResultsOut of the 2844 studies identified, 305 had a full text evaluation and 27 studies met the criteria to be included in this analysis. All but one were retrospective studies. The 10-yr local control (LC) rate ranged from 71% to 100%. The 10-yr progression-free-survival rate ranged from 55% to 97%. The prescription dose ranged typically between 12 and 15nGy, delivered in a single fraction. Toxicity rate was generally low.ConclusionThe current literature supporting SRS for benign intracranial meningioma lacks level I and II evidence. However, when summarizing the large number of level III studies, it is clear that SRS can be recommended as an effective evidence-based treatment option (recommendation level II) for grade 1 meningioma.

Purpose Brainstem arteriovenous malformations (AVMs) present a formidable therapeutic challenge, and a variety of surgical and non-surgical treatment strategies can be used to obliterate the AVM nidus, eliminating its risk of hemorrhage. However, complete obliteration of brainstem AVMs is often not possible. We aimed to investigate the natural history of brainstem AVMs with incomplete nidus obliteration after initial treatment. Methods Data from consecutive patients who presented to our institution during the study period with a brainstem AVM and residual nidus after treatment were retrospectively reviewed. We evaluated patients for the incidence of AVM rupture and calculated the risk of rupture after treatment resulted in incomplete nidus obliteration. Results A total of 14 patients were included, five of whom suffered rupture after incomplete nidus obliteration (36%). Annual risk of rupture was 4.9% (95% CI: 1.60–11.5) per patient over a median follow-up of 72 months. The most common treatment modality of these patients was SRS-alone (n = 6), and two (33%) patients who underwent this treatment later ruptured after 103 and 130 months. Of the five patients who ruptured after treatment, 80% had already ruptured once, and 80% had an intranidal and/or feeding artery aneurysm. Conclusions Brainstem AVMs with incomplete nidus obliteration are at high risk of future rupture. Patients with brainstem AVMs who have a residual nidus after treatment should be counselled about the risk of AVM rupture and be recommended to undergo close follow-up imaging studies to monitor the nidus.

Neurofibromatosis type 2 (NF2) is a debilitating genetic condition with potential development of multiple meningiomas. We report our experience treating a series of NF2-associated intracranial meningiomas with Gamma Knife radiosurgery (GKRS). Between 1992 and 2013, 15 consecutive patients (age 20-54 years) with 62 intracranial meningiomas were treated with single-fraction GKRS. Fifty-five percent of tumors involved the convexity or parasagittal/falx. The median prescription dose was 16 Gy (range 13-20 Gy). The median tumor diameter was 2.1 cm (range 0.7-4.5 cm). The median radiographic and clinical follow-up periods were 103 and 111 months, respectively. The 5-year and 10-year local controls were both 96 %. The disease specific survival was 93 % at 5 years and 68 % at 10 years. Fifty-three percent of patients had multiple meningiomas and received multiple GKRS treatments (range 1-7) for new or enlarging intracranial meningiomas. 11 (73 %) patients were alive at last follow-up, with 60 (97 %) tumors controlled (smaller or unchanged in size). There were 2 in-field failures, one at 1 year and the other at 3.5 years. There were no marginal failures. Major Complications after GKRS included: 1 case of radiation necrosis, 1 case of post treatment edema, and 1 case of a presumed radiation induced cavernous malformation 5 years after GKRS. GK is an effective treatment for enlarging NF2-associated meningiomas. No cases of malignant transformation or secondary malignancies were seen during the follow-up period.

Background The optimum treatment for cystic vestibular schwannoma (VS) remains controversial. Anecdotally, many treating physicians feel that cystic VSs do not respond to stereotactic radiosurgery (SRS) as well as noncystic tumors. Objective To present outcomes after treatment of predominantly cystic VS with SRS. Methods A prospectively maintained clinical database of patients undergoing Gamma Knife (Elekta Instruments, Stockholm, Sweden) radiosurgery (GKRS) for VS at a single tertiary academic referral center was retrospectively reviewed. Patients diagnosed with cystic VS who were treated with GKRS between 1997 and 2014 were analyzed. Size-matched solid tumors treated with GKRS during this period were selected as controls. Results Twenty patients (12 women; median age at treatment, 56 years; range, 36-85 years) with cystic VS met inclusion criteria. The median radiologic follow-up within the cystic group was 63 months (range, 17-201 months), and the median change in tumor size was -4.9 mm (range, -10.4 to 9.3 mm). Sixteen tumors (80%) shrank, 2 (10%) remained stable, and 2 (10%) enlarged, accounting for a tumor control rate of 90%. The median radiologic follow-up in the noncystic control group was 67 months (range, 6-141 months), and the median change in size was -2.0 mm (range, -10.4 to 2.5 mm). Tumor control in the solid group was 90%. Comparing only those tumors that decreased in size showed that there was a trend toward a greater reduction within the cystic group ( P = .05). Conclusion The present study demonstrates that tumor control after SRS for cystic VS may not differ from that of noncystic VS in selected cases.

BACKGROUND Surgical resection is typically cited as the optimal treatment of patients with Spetzler-Martin Grade I-II arteriovenous malformation (AVM). OBJECTIVE To report our experience with single-fraction stereotactic radiosurgery (SRS) for Spetzler-Martin Grade I-II AVM. METHODS A prospectively maintained registry was reviewed for patients with nonsyndromic Spetzler-Martin Grade I-II AVM having SRS from 1990 to 2011. Patients with

BACKGROUND Stereotactic radiosurgery (SRS) is a common treatment modality for vestibular schwannoma (VS), with a role in primary and recurrent/progressive algorithms. At our institution, routine magnetic resonance imaging (MRI) is obtained at 6 and 12 mo following SRS for VS. OBJECTIVE To analyze the safety and financial impact of eliminating the 6-mo post-SRS MRI in asymptomatic VS patients. METHODS A prospectively maintained SRS database was retrospectively reviewed for VS patients with 1 yr of post-treatment follow-up, 2005 to 2015. Decisions at 6-mo MRI were binarily categorized as routine follow-up vs clinical action-defined as a clinical visit, additional imaging, or an operation as a direct result of the 6-mo study. RESULTS A total of 296 patients met screening criteria, of whom 53 were excluded for incomplete follow-up and 8 for NF-2. Nine were reimaged prior to 6 mo due to clinical symptoms. Routine 6-mo post-SRS MRI was completed by 226 patients (76% of screened cohort), following from which zero instances of clinical action occurred. When scaled using national insurance database-derived financials-which estimated the mean per-study charge for MRI of the brain with and without contrast at $1767-the potential annualized national charge reduction was approximated as $1 611 504. CONCLUSION For clinically stable VS, 6-mo post-SRS MRI does not contribute significantly to management. We recommend omitting routine MRI before 12 mo, in patients without new or progressive neurological symptoms. If extrapolated nationally to the more than 100 active SRS centers, thousands of patients would be spared an inconvenient, nonindicated study, and national savings in health care dollars would be on the order of millions annually.

Tolosa Hunt syndrome (THS) is characterized by painful ophthalmoplegia secondary to idiopathic granulomatous inflammation of the cavernous sinus. The characteristic finding on MRI is an enhancing T1 isointense and T2 hypo- or hyperintense cavernous sinus mass lesion, which may result in focal narrowing of the ipsilateral internal carotid artery. Although the incidence is quite rare, it is a common diagnostic consideration in cases that present with multiple cranial neuropathies. However, the differential diagnosis for a unilateral cavernous sinus lesion in adults is broad and includes neoplastic, inflammatory (such as sarcoidosis and immunoglobulin G4-related disease [IgG4-RD]), infectious etiologies (such as syphilis and leprosy), as well as vascular lesions. We describe a patient presenting with neurologic symptoms referable to a persistent unilateral cavernous sinus MRI abnormality, initially thought to be consistent with Tolosa-Hunt syndrome, that was clinically but not radiographically responsive to steroids. Following reevaluation due to the presence of new symptoms, pathology revealed that the abnormality was most consistent with chordoma, a rare skull based tumor. In patients with a presumed diagnosis of Tolosa-Hunt syndrome, close clinical and radiographic follow-up is imperative, with early consideration for biopsy in patients that fail to respond to treatment both clinically and radiographically.

OBJECT The optimal treatment for sporadic vestibular schwannoma (VS) is highly controversial. To date, the majority of studies comparing treatment modalities have focused on a narrow scope of technical outcomes including facial function, hearing status, and tumor control. Very few publications have investigated health-related quality of life (HRQOL) differences between individual treatment groups, and none have used a disease-specific HRQOL instrument. METHODS All patients with sporadic small- to medium-sized VSs who underwent primary microsurgery, stereotactic radiosurgery (SRS), or observation between 1998 and 2008 were identified. Subjects were surveyed via postal questionnaire using the 36-Item Short Form Health Survey (SF-36), the 10-item Patient-Reported Outcomes Measurement Information System short form (PROMIS-10), the Glasgow Benefit Inventory (GBI), and the Penn Acoustic Neuroma Quality-of-Life (PANQOL) scale. Additionally, a pool of general population adults was surveyed, providing a nontumor control group for comparison. RESULTS A total of 642 respondents were analyzed. The overall response rate for patients with VS was 79%, and the mean time interval between treatment and survey was 7.7 years. Using multivariate regression, there were no statistically significant differences between management groups with respect to the PROMIS-10 physical or mental health dimensions, the SF-36 Physical or Mental Component Summary scores, or the PANQOL general, anxiety, hearing, or energy subdomains. Patients who underwent SRS or observation reported a better total PANQOL score and higher PANQOL facial, balance, and pain subdomain scores than the microsurgical cohort (p < 0.02). The differences in scores between the nontumor control group and patients with VS were greater than differences observed between individual treatment groups for the majority of measures. CONCLUSIONS The differences in HRQOL outcomes following SRS, observation, and microsurgery for VS are small. Notably, the diagnosis of VS rather than treatment strategy most significantly impacts quality of life. Understanding that a large number of VSs do not grow following discovery, and that intervention does not confer a long-term HRQOL advantage, small- and medium-sized VS should be initially observed, while intervention should be reserved for patients with unequivocal tumor growth or intractable symptoms that are amenable to treatment. Future studies assessing HRQOL in VS patients should prioritize use of validated disease-specific measures, such as the PANQOL, given the significant limitations of generic instruments in distinguishing between treatment groups and tumor versus nontumor subjects.

Objective The best management of patients with brain arteriovenous malformations (BAVM) is controversial. The radiosurgery-based arteriovenous malformation (AVM) score (RBAS) was developed to predict outcomes for patients with BAVM having stereotactic radiosurgery (SRS). Methods The RBAS is calculated for patients with BAVM having SRS at our center as part of our prospectively maintained SRS database (RBAS = [0.1] [AVM volume; cm 3 ] + [0.02] [patient age; years] + [0.5] [AVM location; 0 = cerebral/cerebellar hemispheres/corpus callosum, 1 = basal ganglia/thalamus/brainstem]). Review of the SRS database from 1990 to 2009 identified 80 patients with a RBAS ≤1 and at least 1 year of follow-up. The primary end point of the study was a decline in modified Rankin Score. The mean follow-up after SRS was 68 months (range, 12−133). Results The mean patient age was 25.2 years (range, 7−44). Seventy-six patients (95%) had superficially located BAVMs; the mean BAVM volume was 2.3 cm 3 (range, 0.1−8.0). The mean RBAS was 0.76 (range, 0.21−1.00). The patients' MRS before SRS was 0 (n = 52, 65%), 1 (n = 24, 30%), 2 (n = 3, 4%), and 3 (n = 1, 1%). BAVM obliteration was confirmed in 92% of patients with follow-up beyond 3 years (70/76; 95% confidence interval 84%−97%). No patient had a hemorrhage or a radiation-related complication after SRS. The observed rate of modified Rankin Score decrease after SRS was 0% (0/80; 95% confidence interval 0%−6%). Conclusions SRS provided a high rate of obliteration at very low risk for patients with BVAM with a RBAS ≤1. Patient outcomes after SRS are likely equivalent to resection for younger patients with small-volume BAVM who do not require a craniotomy for clot removal.

OBJECTIVEGeniculate neuralgia (GN) is an uncommon craniofacial pain syndrome attributable to nervus intermedius (NI) dysfunction. Diagnosis and treatment can be challenging, due to the complex nature of ear sensory innervation, resulting in clinical overlap with trigeminal neuralgia (TN) and glossopharyngeal neuralgia (GPN).METHODSA retrospective review of a prospective neurosurgical database at our institution was performed, 2000–2017, with a corresponding systematic literature review. Pain outcomes were dichotomized as unfavorable for unchanged/worsened symptoms versus favorable if improved/resolved. Eight formalin-fixed brains were examined to describe NI at the brainstem.RESULTSEleven patients were surgically treated for GN—9 primary, 2 reoperations. The median age was 48, 7 patients were female, and the median follow-up was 11 months (range 3–143). Seven had ≥ 2 probable cranial neuralgias. NI was sectioned in 9 and treated via microvascular decompression (MVD) in 2. Five patients underwent simultaneous treatment for TN (4 MVD; 1 rhizotomy) and 5 for GPN (3 MVD; 2 rhizotomy). Eleven reported symptomatic improvement (100%); 8 initially reported complete resolution (73%). Pain outcomes at last contact were favorable in 8 (73%)—all among the 9 primary operations (89% vs 0%, p = 0.054). Six prior series reported outcomes in 111 patients.CONCLUSIONSGN is rare, and diagnosis is confounded by symptomatic overlap with TN/GPN. Directed treatment of all possible neuralgias improved pain control in almost all primary operations. Repeat surgery seems a risk factor for an unfavorable outcome. NI is adherent to superomedial VIII at the brainstem; the intermediate/cisternal portion is optimal for visualization and sectioning.

Background When clinical presentation, laboratory studies, or imaging cannot diagnose cavernous sinus (CS) and/or Meckel's cave (MC) lesions, biopsy may be necessary. Objective To review our institutional series of biopsies of indeterminate CS and MC lesions. Methods Records from January 1994 to June 2016 were searched for biopsied indeterminate CS and MC lesions. We defined indeterminate as having an atypical imaging appearance or a broad differential and the need for tissue for definitive diagnosis. We defined primary tumors as originating from cells inherent or near the CS and MC. Results Eighty-five patients were included (median age 59 [2-85] yr); 22 (28%) had a cancer history. Approaches included frontotemporal craniotomy (n = 48, 56%), endoscopic endonasal (n = 20, 24%), percutaneous transforamen ovale (n = 12, 14%), or retrosigmoid craniotomy (n = 5, 6%). Final diagnosis was metastatic in 27 (32%), primary in 21 (25%), inflammatory in 13 (15%), hematologic in 11 (13%), fungal in 5 (5%), and nondefinitive or nondiagnostic in 8 (10%) patients. Thirteen (59%) patients with a cancer history (n = 22) had a diagnosis consistent with their prior cancer; the remaining had a second pathology (n = 6, 27%) or nondiagnostic biopsy (n = 3, 14%). Two patients had surgical complications resulting in death. Conclusion In this patient cohort, metastatic tumors were the most likely pathology. The biopsy threshold should be lower in patients with a cancer history if clinical or radiographic diagnosis is uncertain as 27% had a second disease. However, we consider biopsy as a last resort because the risk of major morbidity/mortality, while low, is not zero.

OBJECTIVENelson-Salassa syndrome (NSS) is a rare consequence of bilateral adrenalectomy (ADX) for refractory hypercortisolism due to Cushing disease (CD). Although classically defined by rapid growth of a large, invasive, adrenocorticotropin hormone (ACTH)–secreting pituitary tumor after bilateral ADX that causes cutaneous hyperpigmentation, visual disturbance, and high levels of ACTH, clinical experience suggests more variability.METHODSThe authors conducted a retrospective chart review of all patients 18 years and older with a history of bilateral ADX for CD, adequate pituitary MRI, and at least 2 years of clinical follow-up. Statistical tests included Student's t-test, chi-square test, Fisher's exact test, multivariate analysis, and derived receiver operating characteristic curves.RESULTSBetween 1956 and 2015, 302 patients underwent bilateral ADX for the treatment of hypercortisolism caused by CD; 88 had requisite imaging and follow-up (mean 16 years). Forty-seven patients (53%) had radiographic progression of pituitary disease and were diagnosed with NSS. Compared with patients who did not experience progression, those who developed NSS were significantly younger at the time of CD diagnosis (33 vs 44 years, p = 0.007) and at the time of bilateral ADX (35 vs 49 years, p = 0.007), had larger tumors at the time of CD diagnosis (6 mm vs 1 mm, p = 0.03), and were more likely to have undergone external-beam radiation therapy (EBRT, 43% vs 12%, p = 0.005). Among NSS patients, the mean tumor growth was 7 mm/yr (SE 6 mm/yr); the median tumor growth was 3 mm/yr. Prevalence of pathognomonic symptoms was low; the classic triad occurred in 9%, while hyperpigmentation without visual field deficit was observed in 23%, and 68% remained asymptomatic despite radiographic disease progression. NSS required treatment in 14 patients (30%).CONCLUSIONSNSS is a prevalent sequela of CD after bilateral ADX and affects more than 50% of patients. However, although radiological evidence of NSS is common, it is most often clinically indolent, with only a small minority of patients developing the more aggressive disease phenotype characterized by clinically meaningful symptoms and indications for treatment. Young age at the time of CD diagnosis or treatment with bilateral ADX, large tumor size at CD diagnosis, and EBRT are associated with progression to NSS and may be markers of aggressiveness.

Background Stereotactic radiosurgery is widely applied to deliver additional dose to head and neck tumors. However, its safety and efficacy remains equivocal. Methods One hundred eighty-four patients with primary head and neck cancers treated between January 1990 and August 2012 with Gamma Knife stereotactic radiosurgery were retrospectively reviewed. Results Two hundred fifteen sites were treated with Gamma Knife stereotactic radiosurgery among 184 patients. Fifty-one percent of patients received concurrent external beam radiotherapy (EBRT), 72% had prior surgery, and 46% received chemotherapy. Most (44%) had squamous cell carcinoma and most patients (65%) were treated for recurrent disease. With a median follow-up of 17.3 months, 12-month local control was 82%. Late effects occurred in 59 patients with the most common being temporal lobe necrosis (15 patients). Conclusion Radiosurgery can provide tumor control for patients with head and neck cancers involving the skull base. Long-term follow-up is important in survivors to identify late effects. © 2014 Wiley Periodicals, Inc. Head Neck 37: 1557–1562, 2015

Background Management of neurofibromatosis type 2 (NF2)-associated vestibular schwannomas (VSs) remains controversial. Stereotactic radiosurgery (SRS) with conventional dosing is less effective for NF2-related VS compared with sporadic lesions. Objective To evaluate optimal SRS dose parameters for NF2-related VS and to report long-term outcomes. Methods A prospective database was reviewed and outcome measures, including radiographic progression, American Academy of Otolaryngology-Head and Neck Surgery hearing class, and facial nerve function, were analyzed. Progression-free survival was estimated with Kaplan-Meier methods. Associations between tumor progression and radiosurgical treatment parameters, tumor volume, and patient age were explored with the use of Cox proportional hazards regression. Results Between 1990 and 2010, 26 patients with 32 NF2-related VSs underwent SRS. Median marginal dose and tumor volume were 14 Gy and 2.7 cm, respectively. Twenty-seven tumors (84%) showed no growth (median follow-up, 7.6 years). Kaplan-Meier estimates for 5- and 10-year progression-free survival were 85% and 80%, respectively. Cox proportional hazards demonstrated a significant inverse association between higher marginal doses and tumor progression (hazard ratio, 0.49; 95% confidence interval, 0.17-0.92; P = .02). Audiometric data were available in 30 ears, with 12 having class A/B hearing before SRS. Only 3 maintained serviceable hearing at the last follow-up. Four underwent cochlear implantation. Initially, 3 achieved open-set speech recognition, although only 1 experienced long-term benefit. Facial nerve function remained stable in 50% of cases. Conclusion Higher marginal doses than commonly prescribed for sporadic VS were associated with improved tumor control in patients with NF2. Hearing outcomes were poor even when contemporary reduced marginal doses were used. However, SRS allows an anatomically preserved cochlear nerve and may permit hearing rehabilitation with cochlear implantation. Further consideration should be given to optimum dosing to achieve long-term control while maximizing functional outcomes. Abbreviations HB, House-BrackmannNF2, neurofibromatosis type 2SRS, stereotactic radiosurgeryVS, vestibular schwannoma.

Background Microvascular decompression (MVD) is an established surgical therapy for patients with idiopathic trigeminal neuralgia (TN). The role of MVD in patients with definite or suspected multiple sclerosis (MS) remains controversial. Methods During the period 2000–2012, 10 patients with medically refractory TN and ipsilateral brainstem T2 hyperintensity underwent MVD. In 5 patients, additional clinical features suspicious for MS were present, including prior optic neuritis ( n = 2), multiple disseminated lesions ( n = 3), and elevated immunoglobulin G index ( n = 2). One patient had failed prior percutaneous surgery; 1 patient had Burchiel type 2 TN. Follow-up (median, 14 months) was censored at the time of additional surgery ( n = 6) or last clinic visit ( n = 4). Results Neurovascular compression was confirmed at surgery from the superior cerebellar artery (SCA) plus adjacent vein ( n = 4), vein alone ( n = 3), SCA alone ( n = 2), and SCA plus anterior inferior cerebellar artery ( n = 1). Initially after MVD, 8 patients (80%) were pain-free and subsequently tapered off medications for their facial pain. Pain recurred in 6 patients at a median of 4 months (range, 1–23 months). Actuarial rates of being pain-free off medications were 50% at 3 months and 15% at 2 years. In 6 patients, additional treatments were performed, including glycerol rhizotomy ( n = 4), radiosurgery ( n = 2), balloon compression ( n = 2), and repeat MVD ( n = 1). At last contact, 5 of the 6 patients who were retreated were pain-free. Conclusions Facial pain outcomes after MVD in patients with suspected MS-related TN are poor compared with outcomes for patients with idiopathic TN. This study provides further support that many patients with MS-related TN have pain that is centrally mediated, reducing the effectiveness of procedures performed on the trigeminal root, ganglion, or divisions.

Background To assess the risk of cerebrovascular accidents (CVAs) and second brain tumors (SBTs) in patients with pituitary adenoma after surgery or radiotherapy. Methods A cohort of 143 people from Olmsted County, who were diagnosed with pituitary adenoma between 1933 and 2000, was studied. Only patients from Olmsted County were included because of the unique nature of medical care in Olmsted County, which allows the ascertainment of virtually all cases of pituitary adenoma for this community's residents and comparisons to the general population in the county. Surgical resection was performed in 76 patients, 29 patients underwent radiotherapy (with 21 undergoing both surgery and radiotherapy), 5 patients were reirradiated, and 59 patients were managed conservatively and observed. Results Median follow-up was 15.5 years. There was no difference in CVA-free survival between treatment groups. On univariate analysis age > 60 years (hazard ratio [HR], 11.93; 95% CI, 6.26–23.03; P < .001); male sex (HR, 3.67; 95% CI, 2.03–6.84; P < .001), and reirradiation (HR, 3.41; 95% CI, 1.05–9.68; P = .04) were associated with worse CVA-free survival. In multivariate analysis, only age > 60 years was associated with worse CVA-free survival. Compared with the general population, there was a 4-fold increase in the rate of CVAs in pituitary adenoma patients (HR, 4.2; 95% CI, 2.8–6.1). Two patients developed SBT (an irradiated patient and a surgically managed patient). Conclusion CVA is a significant risk for patients with pituitary tumors, but treatment does not seem to impact the risk. Even with long-term follow-up, SBTs are a rare event regardless of treatment modality.

BACKGROUND Esthesioneuroblastoma (ENB) is a rare malignant neuroendocrine tumor considered to be radiation sensitive. Local recurrence may be treated in a variety of ways, including stereotactic radiosurgery (SRS); however, little information on its effectiveness is available. OBJECTIVE To determine whether SRS is effective in providing local control for recurrent ENB. METHODS This was a retrospective single-institution experience including 109 patients with ENB treated at the Mayo Clinic (1962-2009). Sixty-three patients presented with Kadish stage C disease, and 21 patients developed local recurrence. Of these 21 patients, 7 patients underwent SRS at our institution and an additional patient underwent SRS after transnasal biopsy. Therefore, a total of 8 patients are reported. RESULTS The median age at time of local recurrence was 50 years. All patients had Kadish C disease at initial diagnosis. Six of 8 patients were found to have Hyams grade 3 disease; the remaining 2 patients had grade 2 disease. The median treatment volume was 8.4 cm (mean, 18.9 cm; range, 1.4-76.3 cm), and the median dose to the tumor margin was 15 Gy (mean, 14.4 ± 2.2 Gy; range, 10-18 Gy). Of the 16 treatments, 13 had adequate follow-up to assess treatment response, with 92% achieving local control over a median follow-up of 42 months from the time of SRS. Five lesions decreased in size, 7 lesions stabilized, and only 1 lesion had in-field progression. There were no documented complications secondary to SRS. CONCLUSION SRS appears to be a reasonable and safe option for treatment of intracranial recurrence of ENB.

Background and Purpose— The best management of patients with unruptured brain arteriovenous malformations (BAVM) is controversial. In this study, we analyzed the stroke rate and functional outcomes of patients having stereotactic radiosurgery (SRS) for unruptured BAVM using the same eligibility criteria and primary end points as the ARUBA trial. Methods— Retrospective observational study of 174 ARUBA-eligible patients having SRS from 1990 to 2005. Results— The median follow-up after SRS was 64 months. Fifteen patients (8.7%) had a hemorrhagic stroke at a median of 21 months after SRS. Six patients (3.5%) had a focal neurological deficit and 4 patients died (2.3%). The risk of stroke or death was 10.3% at 5 years and 11.5% at 10 years. Twelve additional patients (6.9%) had a focal neurological deficit from either radiation-related complications (n=7) or subsequent resection (n=5). The risk of patients’ having clinical impairment (modified Rankin Score ≥2) was 8.4% at 5 years and 12.0% at 10 years. Increasing BAVM volume was associated with both stroke or death (hazard ratio=1.06; 95% confidence interval, 1.0–1.11; P =0.04) and clinical impairment (hazard ratio=1.06; 95% confidence interval, 1.01–1.09; P =0.01). The 10-year risk of stroke or death and clinical impairment for patients with BAVM ≤5.6 cm 3 was 5% and 4%, respectively. Conclusions— The observed risk of stroke or death after SRS was approximately 2% per year for the first 5 years after SRS, declining to 0.2% annually for years 6 to 10. Patients with small volume BAVM may benefit from SRS compared with the natural history of unruptured BAVM over the planned follow-up interval of the ARUBA trial (5–10 years).

Background Skull base cerebrospinal fluid (CSF) leak after gamma knife radiosurgery (GKRS) is a very rare complication. In patients who were treated with both GKRS and transsphenoidal resection (TSR) for pituitary lesions, early CSF leak occurs at a comparable rate with the general TSR population (4%). Delayed CSF leak occurring more than a year after TSR, GKRS, or dual therapy is exceedingly rare. Methods Retrospective chart review and review of the literature. Results We present 2 cases of delayed CSF leak after GKRS to treat pituitary adenoma. One patient developed CSF rhinorrhea 16 years after GKRS for growth hormone–producing pituitary adenoma. The patient had previously undergone TSR surgery 7 years prior to GKRS without complication. Additionally, a second patient developed high-flow CSF rhinorrhea 2 years after GKRS for a prolactinoma that failed dopamine agonist therapy. Both patients underwent a complicated clinical course after presentation, requiring multiple revisions for definitive CSF leak repair. Conclusions Delayed CSF leak is a rare but serious complication after GKRS independent of TSR status; urgent repair is the treatment of choice. Based on our experience, these leaks have the potential to be refractory, and we recommend aggressive reconstruction, preferably with a vascularized flap, and potentially supplemented by placement of a lumbar drain and acetazolamide. Current evidence is scant and provides little insight regarding an underlying mechanism, which may include bony destruction by the tumor, delayed radiation necrosis, or a secondary empty sella syndrome.

Whole brain radiotherapy (WBRT) significantly improves tumor control in the brain after stereotactic radiosurgery (SRS), yet because of its association with cognitive decline, its role in the treatment of patients with brain metastases remains controversial.To determine whether there is less cognitive deterioration at 3 months after SRS alone vs SRS plus WBRT.At 34 institutions in North America, patients with 1 to 3 brain metastases were randomized to receive SRS or SRS plus WBRT between February 2002 and December 2013.The WBRT dose schedule was 30 Gy in 12 fractions; the SRS dose was 18 to 22 Gy in the SRS plus WBRT group and 20 to 24 Gy for SRS alone.The primary end point was cognitive deterioration (decline1 SD from baseline on at least 1 cognitive test at 3 months) in participants who completed the baseline and 3-month assessments. Secondary end points included time to intracranial failure, quality of life, functional independence, long-term cognitive status, and overall survival.There were 213 randomized participants (SRS alone, n = 111; SRS plus WBRT, n = 102) with a mean age of 60.6 years (SD, 10.5 years); 103 (48%) were women. There was less cognitive deterioration at 3 months after SRS alone (40/63 patients [63.5%]) than when combined with WBRT (44/48 patients [91.7%]; difference, -28.2%; 90% CI, -41.9% to -14.4%; P .001). Quality of life was higher at 3 months with SRS alone, including overall quality of life (mean change from baseline, -0.1 vs -12.0 points; mean difference, 11.9; 95% CI, 4.8-19.0 points; P = .001). Time to intracranial failure was significantly shorter for SRS alone compared with SRS plus WBRT (hazard ratio, 3.6; 95% CI, 2.2-5.9; P .001). There was no significant difference in functional independence at 3 months between the treatment groups (mean change from baseline, -1.5 points for SRS alone vs -4.2 points for SRS plus WBRT; mean difference, 2.7 points; 95% CI, -2.0 to 7.4 points; P = .26). Median overall survival was 10.4 months for SRS alone and 7.4 months for SRS plus WBRT (hazard ratio, 1.02; 95% CI, 0.75-1.38; P = .92). For long-term survivors, the incidence of cognitive deterioration was less after SRS alone at 3 months (5/11 [45.5%] vs 16/17 [94.1%]; difference, -48.7%; 95% CI, -87.6% to -9.7%; P = .007) and at 12 months (6/10 [60%] vs 17/18 [94.4%]; difference, -34.4%; 95% CI, -74.4% to 5.5%; P = .04).Among patients with 1 to 3 brain metastases, the use of SRS alone, compared with SRS combined with WBRT, resulted in less cognitive deterioration at 3 months. In the absence of a difference in overall survival, these findings suggest that for patients with 1 to 3 brain metastases amenable to radiosurgery, SRS alone may be a preferred strategy.clinicaltrials.gov Identifier: NCT00377156.

BACKGROUND Stereotactic radiosurgery (SRS) has been performed on patients with cerebral arteriovenous malformations (AVMs) for over 40 years. OBJECTIVE To evaluate the impact of treatment period on obliteration, intracranial hemorrhage (ICH), and radiation-induced complications (RICs). METHODS Retrospective comparison of 381 AVM patients having SRS during a 20-year period (group 1, January 1990 through March 1997, n = 160; group 2, April 1997 through December 2009, n = 221). The median radiological and clinical follow-up after initial SRS was 77 months and 93 months, respectively. RESULTS Obliteration was 59.1% at 4 years and 85.1% at 8 years. Obliteration was more common in patients with hemispheric or cerebellar AVMs (P = .001), smaller prescription isodose volume (PIV) (P < .001), and group 1 patients (P < .001). The ICH rate was 7.7% at 4 years and 10.6% at 8 years. ICH was more common in older patients (P = .02), patients with deep AVM (P = .01), and larger PIV (P < .001). There was no difference in the ICH rate between the treatment groups (P = .18). The rate of permanent RICs was 4.4% at 4 years and 8.6% at 8 years. RICs were more common with larger PIVs (P < .001) and group 1 patients (P = .02). There was no difference in the number of patients having obliteration without new deficits between the 2 treatment periods (68.8% vs 73.3%, P = .33). CONCLUSION Advances in SRS procedures over the past 20 years have resulted in a lower risk of RIC, but fewer patients had AVM obliteration. Increasing the prescription dose for patients with medium- and large-volume AVMs by using current conformal dose-planning techniques may improve the obliteration rate while maintaining a low risk of RICs.

Background Radiation-based treatment options of large intracranial arteriovenous malformations (AVM) must balance the likelihood of obliteration with the risk of adverse radiation effects (ARE). Objective To analyze the efficacy and risks of volume-staged stereotactic radiosurgery (VS-SRS) for AVM. Methods Retrospective study of 34 AVM patients having VS-SRS between 1997 and 2012. A median of 2 stages (range, 2-4) was used to treat a median AVM volume of 22.2 cm 3 (range, 7.4-56.7). The median AVM margin dose was 16 Gy (range, 14-18); the median radiosurgery-based AVM score was 2.81 (range, 1.54-6.45). The median follow-up after VS-SRS was 8.2 years (range, 3-13.3). Results Nidus obliteration was noted in 18 patients (53%) after VS-SRS. The rate of obliteration was 14% at 3 years, 54% at 5 years, and 75% at 7 years. Six patients (18%) had 11 bleeds after VS-SRS. Two patients (6%) remained neurologically stable, 2 (6%) patients had significant deficits, and 2 patients (6%) died. The actuarial risk of a first bleed after VS-SRS was 6% at 1 year, 12% at 3 years, and 19% at 7 years. Six patients (18%) underwent repeat SRS; all achieved nidus obliteration for an overall cure rate of 71%. Two patients (6%) had a permanent ARE after VS-SRS or repeat SRS. Conclusion VS-SRS permitted large volume intracranial AVM to be treated with a low rate of ARE. Further study is needed on dose escalation and decreasing the treatment volume per stage to determine if this will increase the rate of obliteration with this technique.

Background Stereotactic radiosurgery (SRS) of benign intracranial meningiomas is an accepted management option for well-selected patients. Objective To analyze patients who had single-fraction SRS for benign intracranial meningiomas to determine factors associated with tumor control and neurologic complications. Methods Retrospective review was performed of 416 patients (304 women/112 men) who had single-fraction SRS for imaging defined (n = 252) or confirmed World Health Organization grade I (n = 164) meningiomas from 1990 to 2008. Excluded were patients with radiation-induced tumors, multiple meningiomas, neurofibromatosis type 2, and previous or concurrent radiotherapy. The majority of tumors (n = 337; 81%) involved the cranial base or tentorium. The median tumor volume was 7.3 cm; the median tumor margin dose was 16 Gy. The median follow-up was 60 months. Results The disease-specific survival rate was 97% at 5 years and 94% at 10 years. The 5- and 10-year local tumor control rate was 96% and 89%, respectively. Male sex (hazard ratio [HR]: 2.5, P = .03), previous surgery (HR: 6.9, P = .002) and patients with tumors located in the parasagittal/falx/convexity regions (HR: 2.8, P = .02) were negative risk factors for local tumor control. In 45 patients (11%) permanent radiation-related complications developed at a median of 9 months after SRS. The 1- and 5-year radiation-related complication rate was 6% and 11%, respectively. Risk factors for permanent radiation-related complication rate were increasing tumor volume (HR: 1.05, P = .008) and patients with tumors of the parasagittal/falx/convexity regions (HR: 3.0, P = .005). Conclusion Single-fraction SRS at the studied dose range provided a high rate of tumor control for patients with benign intracranial meningiomas. Patients with small volume, nonoperated cranial base or tentorial meningiomas had the best outcomes after single-fraction SRS.

Object Glomus tumors are rare skull base neoplasms that frequently involve critical cerebrovascular structures and lower cranial nerves. Complete resection is often difficult and may increase cranial nerve deficits. Stereotactic radiosurgery has gained an increasing role in the management of glomus tumors. The authors of this study examine the outcomes after radiosurgery in a large, multicenter patient population. Methods Under the auspices of the North American Gamma Knife Consortium, 8 Gamma Knife surgery centers that treat glomus tumors combined their outcome data retrospectively. One hundred thirty-four patient procedures were included in the study (134 procedures in 132 patients, with each procedure being analyzed separately). Prior resection was performed in 51 patients, and prior fractionated external beam radiotherapy was performed in 6 patients. The patients' median age at the time of radiosurgery was 59 years. Forty percent had pulsatile tinnitus at the time of radiosurgery. The median dose to the tumor margin was 15 Gy. The median duration of follow-up was 50.5 months (range 5–220 months). Results Overall tumor control was achieved in 93% of patients at last follow-up; actuarial tumor control was 88% at 5 years postradiosurgery. Absence of trigeminal nerve dysfunction at the time of radiosurgery (p = 0.001) and higher number of isocenters (p = 0.005) were statistically associated with tumor progression–free tumor survival. Patients demonstrating new or progressive cranial nerve deficits were also likely to demonstrate tumor progression (p = 0.002). Pulsatile tinnitus improved in 49% of patients who reported it at presentation. New or progressive cranial nerve deficits were noted in 15% of patients; improvement in preexisting cranial nerve deficits was observed in 11% of patients. No patient died as a result of tumor progression. Conclusions Gamma Knife surgery was a well-tolerated management strategy that provided a high rate of long-term glomus tumor control. Symptomatic tinnitus improved in almost one-half of the patients. Overall neurological status and cranial nerve function were preserved or improved in the vast majority of patients after radiosurgery.

Object Gamma Knife surgery (GKS) for vestibular schwannoma (VS) is an accepted treatment for small- to medium-sized tumors, generally smaller than 2.5 cm in the maximum posterior fossa dimension. The purpose of this study was to evaluate the efficacy and toxicity of GKS for larger tumors. Methods Prospectively collected data were analyzed for 22 patients who had undergone GKS for VSs larger than 2.5 cm in the posterior fossa diameter between 1997 and 2006. No patient had symptomatic brainstem compression at the time of GKS. The median treated tumor volume was 9.4 cm3 (range 5.3–19.1 cm3). The median maximum posterior fossa diameter was 2.8 cm (range 2.5–3.8 cm). The median tumor margin dose was 12 Gy (range 12–14 Gy). Serial imaging, audiometry (10 patients with serviceable hearing pre-GKS), and clinical follow-up were available for a median of 66 months (range 26–121 months). Tumor control failure was defined as either a progressive increase in tumor diameter of at least 2 mm in any dimension or a later resection. Results Four patients met the criteria for GKS failure, including 1 patient who demonstrated sarcomatous degeneration more than 7 years after GKS and died 3 months after microsurgical debulking. An enlarging cystic component was the surgical indication in 1 of the 2 patients who required resection, although 27% of tumors (6 lesions) were cystic before GKS. The 3-year actuarial rate of tumor control, freedom from new facial neuropathy, and preservation of functional hearing were 86%, 92%, and 47%, respectively. At 5 years post-GKS, these rates decreased to 82%, 85%, and 28%, respectively. At the most recent follow-up, 91% of tumors were smaller than at the time of GKS and the median maximum posterior fossa diameter reduction was 26%. On multivariate analysis, none of the following factors was associated with GKS failure, new facial weakness, new trigeminal neuropathy, or loss of serviceable hearing: patient age, tumor volume, tumor margin dose, and preoperative cranial nerve dysfunction. Conclusions Single-session radiosurgery is a successful treatment for the majority of patients with larger VSs. Although tumor control rates are lower than those for smaller VSs managed with GKS, the cranial nerve morbidity of GKS is significantly lower than that typically achieved via resection of larger VSs.

The role of surgery for patients with medically refractory trigeminal neuralgia (TN) is well established. High-quality magnetic resonance imaging, including gadolinium-enhanced and volume acquisition sequences, should be performed to exclude intracranial tumors or demyelinating disease as the cause of the pain, as well as to clearly demonstrate the trigeminal nerve and adjacent blood vessels. For physiologically healthy patients with Type 1 TN, a microvascular decompression (MVD) is the preferred surgical approach because of its high rate of complete pain relief, the durability of the pain relief, and the fact that trigeminal injury is not required for pain relief. Patients with recurrent TN after a failed MVD, patients with significant medical comorbidities, and patients with multiple sclerosis-related TN are generally recommended to undergo less invasive, destructive surgical techniques aimed at providing pain relief by damaging the trigeminal nerve.