Gamma Knife radiosurgery for the management of glomus jugulare tumors: A systematic review and report of the experience of a radioneurosurgery unit in Latin America.

Background: Glomus jugulare tumors (GJTs) are rare and mainly affect women between the 5th and 6th decades of life. Its localization and anatomic relationships make conventional surgical treatment difficult and with a considerable risk of complications. This manuscript aims to describe the results of Gamma Knife radiosurgery (GKR) in patients with GJT treated in a single center in Latin America, as well as to systematically review the literature to determine the clinical and radiological effectiveness of this technique. Methods: A search of information from January 1995 to June 2023 was performed. Twenty-two articles reporting 721 GJT patients treated with GKR were included in the study. Variables such as symptomatic control, control of tumor size, and complications were evaluated. These variables were described using measures of central tendency and proportions. For the institutional experience, 77 patients with GJT tumors were included in the study. Pre-treatment clinical variables and follow-up data were collected from medical charts and phone interviews. The Short Form-36 scale was applied to assess the quality of life. The data were analyzed using the statistical program STATA17.0. Results: A total of 721 patients were considered. The median of patients included in these studies was 18.5. The mean age was 58.4 years. The median of symptom control was 89%, and the median of imaging control was 95.7%. In our institution, 77 patients were included in the study. The mean age was 53.2 years. The median hospital stay was 4.92 hours. For the clinical follow-up, information on 47 patients was obtained. An improvement in pre-treatment symptoms was described in 58%, with general symptomatic control of 97%. The tumor-control rate was 95%, and there were statistically significant differences in six of the nine Short Form-36 scale domains. Conclusion: GKR is an effective, safe, and cost-effective technique that offers a high degree of symptomatic and tumor size control in patients with GJT.

MRI radiomics in the prediction of the volumetric response in meningiomas after gamma knife radiosurgery.

PURPOSE: This report presents the first investigation of the radiomics value in predicting the meningioma volumetric response to gamma knife radiosurgery (GKRS). METHODS: The retrospective study included 93 meningioma patients imaged by three Tesla MRI. Tumor morphology was quantified by calculating 337 shape, first- and second-order radiomic features from MRI obtained before GKRS. Analysis was performed on original 3D MR images and after their laplacian of gaussian (LoG), logarithm and exponential filtering. The prediction performance was evaluated by Pearson correlation, linear regression and ROC analysis, with meningioma volume change per month as the outcome. RESULTS: Sixty calculated features significantly correlated with the outcome. The feature selection based on LASSO and multivariate regression started from all available 337 radiomic and 12 non-radiomic features. It selected LoG-sigma-1-0-mm-3D_firstorder_InterquartileRange and logarithm_ngtdm_Busyness as the predictively most robust and non-redundant features. The radiomic score based on these two features produced an AUC = 0.81. Adding the non-radiomic karnofsky performance status (KPS) to the score has increased the AUC to 0.88. Low values of the radiomic score defined a homogeneous subgroup of 50 patients with consistent absence (0%) of tumor progression. CONCLUSION: This is the first report of a strong association between MRI radiomic features and volumetric meningioma response to radiosurgery. The clinical importance of the early and reliable prediction of meningioma responsiveness to radiosurgery is based on its potential to aid individualized therapy decision making.

Gamma knife radiosurgery in pituitary adenomas. A single-center experience / Radiocirugía gamma knife en adenomas hipofisarios: experiencia en un centro

Abstract Stereotactic radiosurgery with gamma knife (GKS) is a treatment option for persistent or recurrent pituitary adenoma. The aim of our study was to report Argentine experience in GKS, assessing the efficacy and safety in our patients with pituitary adenomas. We performed a retrospective analysis of patients with pituitary adenomas treated with GKS between 2002 and 2017 in a single institution. Patient characteristics, biochemical remission rate (for functioning tumors), tumor control rate and adverse effects with GKS were inves tigated. The study cohort comprised 99 patients with a mean follow-up of 63 months: 51 somatotropinomas, 28 non-functioning adenomas, 15 corticotropinomas, 2 prolactinomas and 3 mixed pituitary tumors. The mean radiation dose was 30.6Gy for corticotropinomas, 29.3Gy for somatotropinomas and 19.6Gy for non-secreting adenomas. Global tumor control rate was 94.2%. Biochemical remission rate was 55.9%, being higher in acromegaly than in Cushing's disease (OR4.7, 95%Ci 2.1-10.4, p<0.0001). The mean time to remission was 29.5 months (range: 6-156). Hypopituitarism occurred in 26% of patients and those with Cushing's disease were more prone to develop new hormone deficiency after GKS (OR 2.93, 95%Ci 1.2-7.2, p = 0.019). This study shows argentine experience with the use of GKS in patients with pituitary adenomas, with similar results to those reported by centers with large radiosurgical experience. We achieved biochemical remission in more than 50% of patients and global tumor control in most of them. Hypopituitarism was the most frequent adverse effect, while others were infrequent.

Resumen La radiocirugía gamma-knife (GKS) constituye una alternativa de tratamiento en adenomas hipofisarios persis tentes o recurrentes. El objetivo de nuestro trabajo fue comunicar la experiencia argentina con GKS, evaluando eficacia y seguridad en nuestros pacientes con adenomas hipofisarios. Realizamos un análisis retrospectivo de pacientes con adenomas hipofisarios tratados con GKS entre 2002 y 2017. Se investigaron: características basales, tasa de remisión bioquímica, tasa de control tumoral y efectos adversos del GKS. Estudiamos 99 pa cientes adultos con un seguimiento medio de 63 meses: 51 somatotropinomas, 28 adenomas no funcionantes, 15 corticotropinomas, 2 prolactinomas y 3 tumores mixtos. La do sis media de radiación fue 30.6 Gy para cortico tropinomas, 29.3 Gy para somatotropinomas y 19.6 Gy para adenomas no secretores. La tasa global de control tumoral fue 94.2%. La tasa de remisión bioquímica fue 55.9%, si endo mayor en acromegalia que en enfermedad de Cushing (OR4.7, 95% Ci 2.1-10.4, p < 0.0001). El tiempo medio hasta la remisión fue 29.5 meses (rango: 6-156). Se produjo hipopituitarismo en el 26% de los pacientes. Aquellos con enfermedad de Cushing fueron más propensos a desarrollar nuevas deficiencias hormonales después del GKS (OR2.93, 95% Ci 1.2-7.2, p = 0.019). Este trabajo muestra la experiencia argentina con GKS en pacientes con adenomas hipofisarios, con resultados similares a los reportados por centros con amplia experiencia radioquirúrgica. Logramos remisión bioquímica en más del 50% de los pacientes y control tumoral global en la mayoría de ellos. El hipopituitarismo fue el efecto adverso más frecuente, mientras que otros fueron infrecuentes.

Gamma knife radiosurgery in pituitary adenomas. A single-center experience.

Stereotactic radiosurgery with gamma knife (GKS) is a treatment option for persistent or recurrent pituitary adenoma. The aim of our study was to report Argentine experience in GKS, assessing the efficacy and safety in our patients with pituitary adenomas. We performed a retrospective analysis of patients with pituitary adenomas treated with GKS between 2002 and 2017 in a single institution. Patient characteristics, biochemical remission rate (for functioning tumors), tumor control rate and adverse effects with GKS were investigated. The study cohort comprised 99 patients with a mean follow-up of 63 months: 51 somatotropinomas, 28 non-functioning adenomas, 15 corticotropinomas, 2 prolactinomas and 3 mixed pituitary tumors. The mean radiation dose was 30.6Gy for corticotropinomas, 29.3Gy for somatotropinomas and 19.6Gy for non-secreting adenomas. Global tumor control rate was 94.2%. Biochemical remission rate was 55.9%, being higher in acromegaly than in Cushing's disease (OR4.7, 95%Ci 2.1-10.4, p <0.0001). The mean time to remission was 29.5 months (range: 6-156). Hypopituitarism occurred in 26% of patients and those with Cushing's disease were more prone to develop new hormone deficiency after GKS (OR 2.93, 95%Ci 1.2-7.2, p = 0.019). This study shows argentine experience with the use of GKS in patients with pituitary adenomas, with similar results to those reported by centers with large radiosurgical experience. We achieved biochemical remission in more than 50% of patients and global tumor control in most of them. Hypopituitarism was the most frequent adverse effect, while others were infrequent.

La radiocirugía gamma-knife (GKS) constituye una alternativa de tratamiento en adenomas hipofisarios persistentes o recurrentes. El objetivo de nuestro trabajo fue comunicar la experiencia argentina con GKS, evaluando eficacia y seguridad en nuestros pacientes con adenomas hipofisarios. Realizamos un análisis retrospectivo de pacientes con adenomas hipofisarios tratados con GKS entre 2002 y 2017. Se investigaron: características basales, tasa de remisión bioquímica, tasa de control tumoral y efectos adversos del GKS. Estudiamos 99 pacientes adultos con un seguimiento medio de 63 meses: 51 somatotropinomas, 28 adenomas no funcionantes, 15 corticotropinomas, 2 prolactinomas y 3 tumores mixtos. La do sis media de radiación fue 30.6 Gy para cortico-tropinomas, 29.3 Gy para somatotropinomas y 19.6 Gy para adenomas no secretores. La tasa global de control tumoral fue 94.2%. La tasa de remisión bioquímica fue 55.9%, si endo mayor en acromegalia que en enfermedad de Cushing (OR4.7, 95% Ci 2.1-10.4, p < 0.0001). El tiempo medio hasta la remisión fue 29.5 meses (rango: 6-156). Se produjo hipopituitarismo en el 26% de los pacientes. Aquellos con enfermedad de Cushing fueron más propensos a desarrollar nuevas deficiencias hormonales después del GKS (OR2.93, 95% Ci 1.2-7.2, p = 0.019). Este trabajo muestra la experiencia argentina con GKS en pacientes con adenomas hipofisarios, con resultados similares a los reportados por centros con amplia experiencia radioquirúrgica. Logramos remisión bioquímica en más del 50% de los pacientes y control tumoral global en la mayoría de ellos. El hipopituitarismo fue el efecto adverso más frecuente, mientras que otros fueron infrecuentes.

Gamma Knife radiosurgery - 12 years of experience in a high-complexity center of a middle-income country.

Background: Gamma Knife radiosurgery (GKR) is a technique that consists of the release of a high dose of ionizing radiation onto a therapeutic target, which has been previously delimited. This technique was described by Lars Leksell and Borje Larsson in 1951. In Colombia, there is only one GKR unit functioning machine nowadays. The objective of this study is to describe the institutional experience of a single institution with Gamma Knife Perfexion over 12 years. Methods: We conducted a retrospective observational study. A total of 1906 medical records, taken from the period between May 4, 2010, and May 4, 2022, were included in the study. Descriptive analysis was performed through STATA 17 as statistic tool. Measures of central tendency were calculated depending on the distribution of the continuous data and proportions were taken into account in the case of qualitative variables. Results: A total of 1906 procedures were performed. Patients from 1 year to 99 years old were treated, with a median age of 51 years. The most frequent diagnoses were meningioma (20.8%), arteriovenous malformation (AVM) (17%), vestibular schwannoma (15.6%), metastases (9.81%), and trigeminal neuralgia (9.12%). At 3-year posttreatment, in meningiomas, tumor size stability was observed in 57.3%, size decrease in 36%, and disappearance in 1.3%. In AVM, complete obliteration of the lesion was described in 36.8% and a decrease in size in 52.6%. Intracranial hemorrhage occurred in 5.2% during the follow-up period and 3.5% of all treated patients required a new procedure due to residual malformation. In vestibular schwannomas, tumor size remained stable in 62.2% and decreased in 28.8%. No new cases of facial paralysis after the procedure were described. At 1-year posttreatment, in metastasis, the size of the lesions remained stable in 40% of the patients, decreased in 47.5%, and disappeared in 2.5%. In trigeminal neuralgia, 88.4% of patients had pain relief and recurrences occurred in 16.6%. Acute complications were generally uncommon, the main ones being headache, pain at frame fixation points, and nausea. Conclusion: Our experience suggests that GKR is a noninvasive procedure with a broad spectrum of clinical applications, low frequency of complications, feasible, with good enough control size of tumor and vascular lesions in images, and good clinical results in the medium and long term.

Comparación dosimétrica en radiocirugía intracraneal entre Cyberknife y un bisturí de rayos gamma y su puesta en marcha Centroamérica / Dosimetric comparison in intracranial radiosurgery between Cyberknife and a gamma knife and its implementation Central America

Introducción: La dupla Cyberknife y bisturí de rayos gamma (Infini) que se describe es la primera en Latinoamérica. Ambas máquinas han mostrado ser los mejores equipos para radiocirugía intracraneal. Se describe la experiencia inicial de Cyberknife en Centroamérica y su incorporación a un programa existente de bisturí de rayos gamma por vía de análisis comparativos dosimétricos. Material y método: En el año 2019 se realizaron planes comparativos y se trataron 180 pacientes con radiocirugía intracraneal con ambos sistemas tanto en patología tumoral, como vascular y funcional. Resultados: En el análisis dosimétrico comparativo en el gradiente de dosis de Infini mostró ser superior a Cyberknife en todos los casos. Para una esfera utilizando el colimador de 4 mm en Infini y de 5 mm en Cyberknife utilizando un plan isocéntrico con el -Trigeminal Path- el gradiente de dosis para Infini fue de 1.5 y para Cyberknife de 1.66. Para los casos de patología el gradiente de dosis media para Infini fue de 3 mm y para Cyberknife de 3.8 mm. Dando un puntaje de gradiente de dosis (Gradient Score Index) si Infini fuese de 100, Cyberknife obtuvo 87.3. Cyberknife mostró mejor conformalidad y cobertura (97% versus 96%) para todos los targets. Entre enero 2019 y enero 2020 se realizaron 180 radiocirugías, 60 con Cyberknife y 120 con Infini, 60 pacientes recibieron 146 sesiones con Cyberknife, radiocirugía fraccionada 39 (65%) y 21 (35%) en sesión única. Las dosis medias en tumores en dosis única fue 15 Gy (12.5 a 25 Gy) y en radiocirugía fraccionada 21 Gy (18 y 35). Ningún paciente ha experimentado toxicidad mayor a grado dos. Conclusiones: El bisturí de rayos gamma rotatorio reveló superioridad en gradiente de dosis con relación al Cyberknife. En su primer año Cyberknife ha mostrado ser una herramienta segura en el tratamiento de patología intracraneal. Más seguimiento clínico y radiológico es necesario para verificar su efectividad comparativa

Introduction: The match between Cyberknife and Infini here described in this article is the first in Latinamerica. Both machines have proven to be the best for intracranial radiosurgery, we describe our initial experience with Cyberknife in Central America and how it was incorporated in an existing gamma ray program by ways of dosimetry comparisons. Methods: During 2019 comparative plans were made and a total of 180 patients received intracranial radiosurgery with both technologies, patients were treated for tumors, vascular anomalies, and functional pathology. Results: Basic dosimetry analysis regarding dose gradient the Infini proved superior to Cyberknife in all plans. For a sphere using the 4 mm collimator in Infini and the 5 mm in Cyberknife along with an isocentric plan using the -Trigeminal Path- dose gradient was 1.5 for Infini and 1.66 for Cyberknife. For the pathology cases Infini was 3 mm and for Cyberknife 3.8 mm on mean. Giving a Gradient Score Index (GSI) if Infini would be 100, Cyberknife would be 87.3. Cyberknife showed better conformality and coverage for all pathology targets (97% versus 96%). From January 2019 to January 2020, 180 intracranial radiosurgeries were done, 60 with Cyberknife and 120 with Infini, 60 patients received 146 sessions with Cyberknife, fractionated scheme 39 (65%) and 21 (35%) single dose. The median dose for tumors was 15 Gy (12.5 a 25 Gy) for single session and 21 Gy (18 y 35) for fractionated scheme. No patient experienced a higher toxicity tan grade two. Conclusions: In its first year Cyberknife has shown to be safe in treating intracranial pathology. Infini had a better dose gradient than Cyberknife. Longer clinical and radiological follow-up is needed to verify its comparative effectiveness.

Metástasis sintomáticas en cerebro superiores a 8. 5 cm3 manejados con radiocirugía / Symptomatic brain metastases greater than 8.5 cm3 managed with radiosurgery

Introducción: Las recomendaciones en el manejo de metástasis superiores a 2 cm especialmente las sintomáticas sugieren cirugía como primera opción. En el presente artículo se discute el papel de radiocirugía como primer manejo de estos pacientes. Material y método: Se evaluaron 37 pacientes sintomáticos con lesiones metastásicas superiores a 8.5 cc tratados con radiocirugía entre el 2011 y el 2018. Resultados: La media de volumen fue de 12.5 cc (8.5-78.4), 9 (24%) pacientes fueron tratados utilizando LINAC, el volumen medio fue de 20 cc (9.2-70 cc). Los tratamientos con Gamma-Ray fueron administrados a 28 (76%) pacientes, 9 (32%) de ellos en protocolo de radiocirugía adaptativa, la dosis para todo el grupo fue de 13.8 Gy (7.5-18 Gy), con dosis media de 17.9 Gy, el volumen medio fue de 16.3 cc (8.5-78.4 cc) para gamma. El Karnofsky al inicio era de 60 (50-70) y de 80 (60-100) a los 30 días (P=0.0001). A los 30 días, 95% de las lesiones habían reducido su tamaño en un 74% (11-95%). La sobrevida media de la serie fue de 19 meses (4-34), el riesgo acumulado de muerte del SNC fue de 5.4%. Conclusiones: Radiocirugía en nuestra experiencia ha mostrado ser eficaz en el control de metástasis a cerebro de gran tamaño, reduciendo la necesidad de cirugí

Introduction: Current recommendations with regards to metastases larger than 2 cm specially in symptomatic patients suggest surgery as a first choice. We analyze the role of upfront radiosurgery as first line of treatment in such patients. Methods: 37 symptomatic patients that harbored tumors greater than 8.5 cc in volume were treated from 2011 to January 2018. Results: The median tumor volume was 12.5 cc (8.5-78.4), 9 (24%) patients were treated with LINAC with a volume of 20 cc (9.2-70 cc). The treatments with GammaRay were administrated to 28 (76%) patients, 9 (32%) of them with adaptive radiosurgery protocol, the prescription dose for the gamma group was 13.8 Gy (7.5-18Gy) mean dose of 17.9 Gy (13.2-23.3 Gy) with a mean volume of 16.3 cc (8.5-78.4 cc). Karnofsky score was 60 (50-70) the day of treatment and 80 (60-100) at 30 days (P=0.0001). At 30 days, 95% of the tumors had reduced in size in a 74% (11-95%) for those evaluated. Median survival was 19 months (4-34), with an accumulative risk of death from central nervous progression of 5.4%. Conclusions: Radiosurgery in our experience has shown to be effective in controlling large metastases, reducing the need for open surgery.

Gamma knife radiosurgery on the trigeminal ganglion for idiopathic trigeminal neuralgia: Results and review of the literature.

BACKGROUND: In the present study, we evaluate the results of gamma knife surgery (GKS) for the treatment of trigeminal neuralgia (TN) using the trigeminal ganglion (TG') and the adjacent fibers of trigeminal nerve as a target. METHODS: From February 2013 to July 2017, we treated 30 cases of TN with GKS. In this group, all patients had an idiopathic typical TN. The radiosurgical target was conformed through two isocenters, 8 and 4 mm at the cavum de Meckel. The maximum dose was 86 Gy using the isodose line of 50%. The median age of the patients was 58.5 (range 28-94) years old, and the median time from diagnosis to GKS was 94 months (range 13-480 months). The median follow-up was 28.5 (range 12-49) months. Clinical outcomes were analyzed. Univariate and multivariate analyses were performed to evaluate factors that correlated with a favorable, pain-free outcome. RESULTS: The mean time to relief of pain was 7 (range 1-40) days. The percentage of patients with significant pain relief was 93.3%. Relapse in pain was noted in four patients at 3, 16, 19, and 36 months. Nine patients were treated in acute status. Fourteen patients had intense pain between 1 and 7 days before the procedure. Among those with the recurrence of their symptoms, one patient had a microvascular decompression. Multivariate regression adjusted for age and sex suggests that, by 40 months, 70% of the patients treated with radiosurgery will remain pain free. At the last follow-up, GKS resulted in pain relief in 86.6% of patients. Our analysis suggests that, using this technique, we can expect that approximately 70% of patients with TN will have some degree of pain improvement at 3 years' post radiosurgery. CONCLUSIONS: GKS on TG appears to be a reasonable treatment option with short latency period, minor collateral effects, and high percentage of pain control. The mechanism of action of radiosurgery could be related to the inactivation of the satellite glial cells in the TG.

Gamma Knife Radiosurgery for ARUBA-Eligible Patients with Unruptured Brain Arteriovenous Malformations.

BACKGROUND: A randomized trial of unruptured brain arteriovenous malformations (ARUBA) reported superior outcomes in conservative management compared to interventional treatment. There were numerous limitations to the study. This study aimed to investigate the efficacy of gamma knife radiosurgery (GKS) for patients with brain arteriovenous malformations (AVMs) by comparing its outcomes to those of the ARUBA study. METHODS: We retrospectively reviewed ARUBA-eligible patients treated with GKS from June 2002 to September 2017 and compared against those in the ARUBA study. AVM obliteration and hemorrhage rates, and clinical outcomes following GKS were also evaluated. RESULTS: The ARUBA-eligible cohort comprised 264 patients. The Spetzler-Martin grade was Grade I to II in 52.7% and III to IV in 47.3% of the patients. The mean AVM nidus volume, marginal dose, and follow-up period were 4.8 cm³, 20.8 Gy, and 55.5 months, respectively. AVM obliteration was achieved in 62.1%. The annual hemorrhage rate after GKS was 3.4%. A stroke or death occurred in 14.0%. The overall stroke or death rate of the ARUBA-eligible cohort was significantly lower than that of the interventional arm of the ARUBA study (P < 0.001) and did not significantly differ from that of the medical arm in the ARUBA study (P = 0.601). CONCLUSION: GKS was shown to achieve a favorable outcome with low procedure-related morbidity in majority of the ARUBA-eligible patients. The outcome after GKS in our patients was not inferior to that of medical care alone in the ARUBA study. It is suggested that GKS is rather superior to medical care considering the short follow-up duration of the ARUBA study.

Linear Accelerator-Based Radiosurgery of Grade I Intracranial Meningiomas.

OBJECTIVE: To determine the local control rate and complication rate in the treatment of grade I intracranial meningiomas. METHODS: A retrospective study was performed of patients with grade I meningioma who received radiosurgery with a dedicated linear accelerator from January 2002 to August 2012 with a minimum follow-up of 2 years. We performed descriptive statistics, logistic regression, and progression-free survival analysis through a Kaplan-Meier curve. RESULTS: Seventy-five patients with 78 grade I meningiomas received radiosurgery, 39 underwent surgery plus adjuvant radiosurgery, and 36 only radiosurgery. The follow-up median time was 68 months (range, 35-120 months). The tumor control rate was 93%, the 5-year progression-free survival was 92% (95% confidence interval, 77%-98%). Acute toxicity was 2.6%, and grade 1-2 late toxicity was 26.6%. Postradiosurgery edema was the main late morbidity. Age >55 years was the only significant factor for attaining a response >75%. The background of surgery before radiosurgery was the only significant prognostic factor for showing edema (odds ratio 5.78 [95% confidence interval, 2.14-15.64]). CONCLUSIONS: The local control rate attained in our series is similar to that reported in other series worldwide; the acute toxicity rate was low and late toxicity was moderate.

Compression of the middle cerebellar tract by posterior fossa tumors before and after Gamma Knife radiosurgery studied with diffusion tensor imaging.

PURPOSE: To investigate if clinically asymptomatic compression of the middle cerebellar tract by extracerebral posterior fossa tumors can produce changes in diffusion tensor imaging (DTI) parameters and if these changes return to normal after Gamma Knife radiosurgery (GKRS). MATERIAL AND METHODS: In 22 patients (12 female, mean age 53.8 years) with posterior fossa tumors (14 schwannomas and 8 meningiomas), the middle cerebellar tract was tracked using DTI data. DTI parameters, such as fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) within these tracts were determined separately on the tumor side and on the contra-lateral side. As a surrogate parameter of tract compression, we used the distance between a tangential line extending between the anterior, not affected part of the pons and the cerebellum, and the furthest extension of the tumor into the lateral rim of the pons. In a subgroup of 15 patients, DTI parameters were recorded after a follow-up of more than 2 years (mean follow-up time 37.5 months) after GKRS and compared to initial findings. RESULTS: Before GKRS, all DTI parameters within the compressed tract had increased. The increase in MD correlated significantly with the degree of tract compression (c = 0.443, p < 0.05). Follow-up examinations after GKRS showed reduction in FA and AD, whereas MD and RD increased. After correction for time elapsed after treatment and tumor type, the changes of MD and AD following treatment correlated significantly with the reduction of tract compression, but not with radiation dose. CONCLUSION: Although without obvious clinical symptoms, disorders of the middle cerebellar tract, as in the case of posterior fossa tumors, persist after reduction of tumor size. Because of the significant correlation between the change of parameters and the reduction of tract compression, initial compression and consequent relief are regarded as the main factors responsible for persistent disorders of the middle cerebellar tract. Radiosurgery dose did not contribute significantly to changes in DTI parameters.

Adaptation of visual cortex to damage of visual pathways in suprasellar tumors before and after gamma knife radiosurgery.

PURPOSE: To demonstrate that lesions of the visual pathways due to suprasellar tumors are accompanied by alterations of the visual cortex and to see if these alterations are reversible after treatment of tumors by gamma knife radiosurgery. MATERIALS AND METHODS: In 36 patients with peri-optic tumors and defects of their visual fields and in an age-matched control group, magnetic resonance imaging was performed before and after treatment. T1 weighted images were evaluated by voxel-based morphometry and correlated to the degree of visual field defects. RESULTS: In patients, grey matter density and cortical thickness were reduced in all parts of the occipital cortex, reaching significance (p < 0.05) in the left superior and middle occipital gyri, with correlation to visual field defects. Follow-up scans showed further reduction in all occipital areas. CONCLUSION: As in other peripheral lesions of the optic system, damage of the optic pathways affects the visual cortex. A prospective follow-up study is needed to determine if these alterations are reversible after successful tumor treatment.

The NASSAU (New ASSessment of cerebral Arteriovenous Malformations yet Unruptured) Analysis: Are the Results From The ARUBA Trial Also Applicable to Unruptured Arteriovenous Malformations Deemed Suitable for Gamma Knife Surgery?

BACKGROUND: The optimal management of unruptured brain arteriovenous malformations (AVMs) is controversial after the ARUBA trial. OBJECTIVE: To confirm or repudiate the ARUBA conclusion that "medical management only is superior to medical management with interventional therapy for unruptured brain arteriovenous malformations." METHODS: Data were collected from 1351 patients treated with Gamma Knife Surgery (GKS; Elekta AB, Stockholm, Sweden) for unruptured and untreated AVMs The follow-up was 8817 yr (median 5.0 and mean 6.5). The results of the analyses were compared to that found in patients randomized to medical management only in the ARUBA trial and extrapolated to a 10-yr time period. Our data were also compared to the natural course in a virtual AVM population for a 25-yr time period. RESULTS: The incidence of stroke was similar among ARUBA and our patients for the first 5 yr. Thereafter, the longer the follow-up, the relatively better outcome following treatment. Both the mortality rate and the incidence of permanent deficits in patients with small AVMs were the same as in untreated patients for the first 2 to 3 yr after GKS, after which GKS patients did better. Patients with large AVMs had a higher incidence of neurological deficits in the first 3 yr following GKS. The difference decreased thereafter, but the time until break even depended on the analysis method used and the assumed risk for hemorrhage in patent AVMs. CONCLUSION: The ARUBA trial conclusion that medical management is superior to medical management with interventional therapy for all unruptured AVMs could be repudiated.

Pediatric glossopharyngeal neuralgia: a comprehensive review.

INTRODUCTION: Debilitating facial pain can seriously affect an individual's daily living. Given that the pathophysiology behind neuropathic and myofascial pain is not fully understood, when chronic facial pain goes undiagnosed, it has been proposed that one of the two is the likely cause. Since their discovery, glossopharyngeal neuralgia (GN) and Eagle's syndrome have been considered mostly conditions afflicting the adult population. However, when pediatric patients present with symptoms resembling GN or Eagle's syndrome, physicians are less apt to include these as a differential diagnosis simply due to the low prevalence and incidence in the pediatric population. MATERIALS AND METHODS: A literature review was performed with the aim to better understand the history of reported cases and to provide a comprehensive report of the anatomical variations that lead to these two conditions as well as the way these variations dictated medical and surgical management. Articles were obtained through Google Scholar and PubMed. Search criteria included key phrases such as pediatric glossopharyngeal neuralgia and pediatric Eagle syndrome. These key phrases were searched independently. PubMed was searched primarily then cross-referenced articles were found via Google Scholar. Results from non-English articles were excluded. RESULTS: A total of 58 articles were reviewed. Most of the articles focused on adult glossopharyngeal neuralgia, and the majority was comprised of case reports. When searched via PubMed, a total of 16 articles and 2 articles returned for glossopharyngeal neuralgia and Eagle's syndrome, respectively. After criteria selection and cross-referencing, a total of seven articles were found with respect to pediatric glossopharyngeal neuralgia. CONCLUSIONS: While they are rare conditions, there are multiple etiologies that lead to the debilitating symptoms of GN and Eagle's syndrome. The clinical anatomy proved notable as multiple causes of GN and Eagle's syndrome are due to variation in the anatomy of the neurovascular structures surrounding the glossopharyngeal nerve, an elongated styloid process, a calcified stylohyoid ligament as well as a calcified stylomandibular ligament. Due to the success of different treatment modalities, the treatment of choice is dependent on clinical judgment.

Planned Gamma Knife Boost After Chemoradiotherapy for Selected Sinonasal and Nasopharyngeal Cancers.

OBJECTIVE: To determine the feasibility of a Gamma Knife boost after intensity-modulated radiation therapy in combination with multimodal therapy in patients with nasopharyngeal carcinoma and sinonasal malignancies with skull base or cavernous sinus involvement. METHODS: Nine patients were treated with intensity-modulated radiation therapy followed by a Gamma Knife boost. In one case Gamma Knife was given as salvage treatment after resection. Five patients had sinonasal malignancies and 4 had nasopharyngeal carcinoma. The mean radiation therapy dose was 64.3 Gy (range, 54-70 Gy) at 2 Gy per fraction. The median interval from completion of radiation therapy to Gamma Knife boost was 2.2 months (range, 1-4 months). The most common indication for Gamma Knife boost was involvement of the cavernous sinus, which was identified in 7 patients. The median margin Gamma Knife dose delivered was 13 Gy (range, 12-20 Gy), with median prescription isodose of 50%. RESULTS: All patients tolerated the procedure well, with minimal toxicity. Local control rates were achieved in all patients and no acute grade 3-5 toxicity was observed. One patient experienced late grade 4 toxicity, which was potentially attributable to treatment. Distant failure occurred in 3 patients (1 patient with nasopharyngeal carcinoma and 2 patients with sinonasal malignancies). CONCLUSIONS: Planned Gamma Knife boost followed intensity-modulated radiation therapy is feasible, safe, and provides excellent local control in patients with sinonasal malignancies and nasopharyngeal carcinoma, particularly in cases with cavernous sinus involvement. Further follow-up will be necessary to determine the long-term effectiveness and complication profile.

Microvascular Decompression Versus Stereotactic Radiosurgery for Trigeminal Neuralgia: A Decision Analysis.

INTRODUCTION:  Both microvascular decompression (MVD) and stereotactic radiosurgery (SRS) have been demonstrated to be effective in treating medically refractory trigeminal neuralgia. However, there is controversy over which one offers more durable pain relief and the patient selection for each treatment. We used a decision analysis model to calculate the health-related quality of life (QOL) for each treatment. METHODS:  We searched PubMed and the Cochrane Database of Systematic Reviews for relevant articles on MVD or SRS for trigeminal neuralgia published between 2000 and 2015. Using data from these studies, we modeled pain relief and complication outcomes and assigned QOL values. A sensitivity analysis using a Monte Carlo simulation determined which procedure led to the greatest QOL. RESULTS: MVD produced a significantly higher QOL than SRS at a seven-year follow-up. Additionally, MVD patients had a significantly higher rate of complete pain relief and a significantly lower rate of complications and recurrence. CONCLUSIONS: With a decision-analytic model, we calculated that MVD provides more favorable outcomes than SRS for the treatment of trigeminal neuralgia.

Estimating the Risks of Adverse Radiation Effects After Gamma Knife Radiosurgery for Arteriovenous Malformations.

BACKGROUND AND PURPOSE: We evaluated risk factors associated with the development of adverse radiation effects (ARE) after stereotactic radiosurgery (SRS) for cerebral arteriovenous malformations (AVMs). METHODS: We evaluated 755 patients with AVM who underwent a single Gamma Knife SRS procedure with at least a 2-year minimum follow-up. Eighty-seven patients (12%) underwent previous resection and 128 (17%) had previous embolization. The median target volume was 3.6 mL (range, 0.1-26.3 mL). The median margin dose was 20 Gy (range, 13-27 Gy). RESULTS: Fifty-five patients (7%) developed symptomatic ARE at a median follow-up of 75 months. The cumulative rates of symptomatic ARE were 3.2%, 5.8%, 6.7%, and 7.5% at 1, 2, 3, and 5 years, respectively. Factors associated with a higher rate of developing symptomatic ARE included larger AVM volume, higher margin dose, larger 12-Gy volume, higher Spetzler-Martin grade, and higher radiosurgery-based score. The rates of developing symptomatic ARE were higher in the brain stem (22%) or thalamus (16%), compared with AVMs located in other brain locations (4%-8%). Nineteen patients (3%) sustained irreversible new neurological deficits related to ARE, and 1 patient died. The rates of irreversible symptomatic ARE were 0.8%, 1.9%, 2.1%, and 2.8% at 1, 2, 3, and 5 years, respectively. The 5-year cumulative rates of irreversible symptomatic ARE were 9.1% in thalamus, 12.1% in brain stem, and 1.4% in other locations. CONCLUSIONS: The knowledge of ARE risk rates after AVM radiosurgery can assist informed consent for patients with AVM, their families, and healthcare providers.

Treatment of epidermoid tumors with gamma knife radiosurgery: Case series.

BACKGROUND: Epidermoid tumors (ETs) are benign lesions that are treated mainly by means of surgical resection, with overall good results. External beam radiotherapy is an alternative treatment for those recurrent tumors, in which a second surgery might not be the best choice for the patient. A little information exists about the effectiveness of gamma knife radiosurgery for the treatment of newly diagnosed and recurrent ETs. We present three cases of ETs treated with gamma knife radiosurgery. CASE DESCRIPTION: Case 1 is a 21-year-old female with an ET located in the left cerebellopontine angle (CPA) with symptoms related to VIII cranial nerve dysfunction. Symptom control was achieved and maintained after single session radiosurgery with gamma knife. Case 2 is a 59-year-old female patient with the history of trigeminal neuralgia secondary to a recurrent ET located in the left CPA. Significant pain improvement was achieved after treatment with gamma knife radiosurgery. Case 3 is a 29-year-old male patient with a CPA ET causing long lasting trigeminal neuralgia, pain relief was achieved in this patient after gamma knife radiosurgery. CONCLUSION: Long-term symptom relief was achieved in all three cases proving that gamma knife radiosurgery is a good and safe alternative for patients with recurrent or nonsurgically treated ETs.

Is there room for stereotactic radiosurgery as an option for third ventricular colloid cysts in patients refusing surgery? A case report and some therapeutic considerations.

BACKGROUND: Colloid cysts of the third ventricle are epithelium-lined mucus-filled cysts usually occurring in the anterosuperior third ventricle. They are benign, slow-growing lesions but with the risk of sudden death. Treatment alternatives for symptomatic cysts include stereotactic aspiration, microsurgical or endoscopic approaches, and shunts for hydrocephalus. CASE DESCRIPTION: The current case describes a patient presenting with hydrocephalus and a colloid cyst. A ventriculoperitoneal shunt was placed as the patient refused a definitive surgical procedure for the removal of the cyst, and stereotactic radiosurgery was then performed. CONCLUSIONS: Stereotactic radiosurgery may be a reasonable alternative with minimal risks in those patients harboring a third ventricle colloid cyst refusing a definitive surgical procedure for resection of the cyst.