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Radiation induced changes (RIC) are the most common complications observed post Gamma Knife radiosurgery (GKRS) and may be observed within 6–18 months post procedure. It has been observed that almost one-third of RICs are symptomatic and half of them are persistent. There is no way to predict which patients will develop these changes and to what extent. This was a prospective analytical pilot study with the aim of understanding the role of serum vascular endothelial growth factor (VEGF) and endostatin as predictive factors for clinically symptomatic RIC in intracranial arteriovenous malformations (AVMs) of Spetzler Martin (SM) grade 3 being managed with primary GKRS. A total of 15 patients were analyzed; 60% of them had a history of bleed. The median volume of AVM nidus was 4.36 mL. One-third of the patients had no imaging changes suggestive of RIC at 1 year follow-up and 2 of the patients had symptomatic RIC needing intervention. Before GKRS, the median values of serum concentration of endostatin and VEGF were 34.98 ng/mL and 168.37 pg/mL, respectively. The serum values of VEGF at 1 month post GKRS was much lower than the pre-GKRS values but not found to be predictive of RIC. No correlation could be observed with the levels of serum endostatin and RIC. Some patients may develop resistant edema and necrosis post GKRS for intracranial AVMs, which may warrant medical and surgical intervention. Serum biomarkers like VEGF and endostatin may vary in the post GKRS period and can be used to identify at-risk cases, however more studies are needed to decide on appropriate time of sampling and identify clinically relevant predictive factors. [ABSTRACT FROM AUTHOR]

Arteriovenous malformations (AVMs) can be treated with observation, surgery, embolization, stereotactic radiosurgery (SRS), or a combination of therapies. SRS has been used for AVMs that pose a high risk of surgery, such as in deep or eloquent anatomic locations. Smaller AVMs, <3 cm, have been shown to have higher rates of complete obliteration after SRS. For AVMs that are a larger size, embolization prior to SRS has been used to reduce the size of the AVM nidus. In this study we analyzed embolization prior to SRS to reduce nidal volume and describe imaging techniques to target for SRS post embolization. We retrospectively reviewed all patients at a single academic institution treated with embolization prior to SRS for treatment of AVMs. We then used contrast enhanced magnetic resonance imaging (MRI) to contour AVM volumes based on pre-embolization imaging and compared to post-embolization imaging. Planned AVM volume prior to embolization was then compared to actual treated AVM volume. We identified 11 patients treated with embolization prior to SRS from 2011–2023. Median AVM nidal volume prior to embolization was 7.69 mL and post embolization was 3.61 ML (P < 0.01). There was a 45.5% obliteration rate at follow up in our series, with 2 minor complications related to radiosurgery. In our cohort, embolization prior to SRS resulted in a statistically significant reduction in AVM nidal volume. Therefore, embolization prior to SRS can result in dose reduction at time of SRS treatment allowing for decreased risk of SRS complications without higher embolization complication rates. [ABSTRACT FROM AUTHOR]

Vestibular schwannomas (VSs) are benign tumors often monitored over time, with measurement techniques for assessing growth rates subject to significant interobserver variability. Automatic segmentation of these tumors could provide a more reliable and efficient for tracking their progression, especially given the irregular shape and growth patterns of VS. Various studies and segmentation techniques employing different Convolutional Neural Network architectures and models, such as U-Net and convolutional-attention transformer segmentation, were analyzed. Models were evaluated based on their performance across diverse datasets, and challenges, including domain shift and data sharing, were scrutinized. Automatic segmentation methods offer a promising alternative to conventional measurement techniques, offering potential benefits in precision and efficiency. However, these methods are not without challenges, notably the "domain shift" that occurs when models trained on specific datasets underperform when applied to different datasets. Techniques such as domain adaptation, domain generalization, and data diversity were discussed as potential solutions. Accurate measurement of VS growth is a complex process, with volumetric analysis currently appearing more reliable than linear measurements. Automatic segmentation, despite its challenges, offers a promising avenue for future investigation. Robust well-generalized models could potentially improve the efficiency of tracking tumor growth, thereby augmenting clinical decision-making. Further work needs to be done to develop more robust models, address the domain shift, and enable secure data sharing for wider applicability. [ABSTRACT FROM AUTHOR]

Radiation necrosis (RN) after stereotactic radiosurgery (SRS) in brain metastases has been extensively evaluated, and RN is correlated with various risk factors. However, no study comprehensively analyzed the correlation between RN and the border zones of the brain that are vulnerable to ischemia. We hypothesized that patients with tumors in the border zone are at high risk of RN. Hence, the current study aimed to assess the correlation between border zone lesions and RN, with consideration of other predetermined factors. This retrospective study included 117 patients with 290 lesions who underwent Gamma Knife SRS. Radiological and clinical analyses were performed to identify factors possibly correlated with RN. Notably, the lesion location was classified into 2 groups (border zone and nonborder zone) based on the blood supply. In total, 22 (18.8%) patients with 22 (7.5%) lesions developed RN. Univariate analysis revealed a significant correlation between RN and external border zone lesions, second course of SRS administered at the same site of the previous SRS, prescribed dose, and tumor volume. Multivariate analysis showed that border zone lesions, second course of SRS at the same site of the previous SRS, and tumor volume were significantly correlated with RN. Patients with tumors in the border zone are at high risk of RN. The potential risks of RN can be attributed hypothetically to hypoperfusion. Hence, the association between RN and border zone lesions seems reasonable. [ABSTRACT FROM AUTHOR]

Target selection during Gamma Knife radiosurgery (GKRS) in cases of tumor-related trigeminal neuralgia is always debatable. We analyzed the correlation of regression of tumor size and degree of release of the nerve with long-term pain control. Between March 2012 and March 2023, 50 cases of tumor-related trigeminal neuralgia were treated with GKRS (tumor was targeted). Radiological findings after GKRS were categorized into 3 types: 1) tumor volume remained same or decreased, additional segment of nerve not seen; 2) tumor volume decreased, additional segment of trigeminal nerve seen, but tumor still adherent to the nerve; 3) tumor volume decreased, adjacent nerve seen completely separated from tumor. Pain score before and after GKRS (Barrow Neurological Institute I–III: good; Barrow Neurological Institute IV and V: poor) was correlated with these subgroups. At median follow-up of 46.5 months, 18 cases showed type 1 radiological response, 23 showed type 2 response, and 9 showed type 3 response. Good pain control was achieved in 10 (55.5%) patients with type 1, 15 (65.21%) with type 2, and 7 (77.8%) with type 3 responses. The outcome differences among these 3 groups were not statistically significant (P = 0.519). Five patients with type 3 radiological response were off medication, which was statistically better than type 1 and type 2 radiological responses, with 3 patients (P = 0.012) and 2 patients (P = 0.002), respectively, still receiving medication. Tumor volume reduction after GKRS may be associated with good pain control in tumor-related trigeminal neuralgia. Further, this allows visualization of additional segment of nerve that can be targeted in a second session for treating recurrent or failed cases. [ABSTRACT FROM AUTHOR]

Resection of meningiomas (THMs) at the torcular Herophili poses challenges to surgeons due to complex regional anatomy. The current study aims to evaluate factors affecting the extent of resections, progression-free survival, and the role of radiation. We did a retrospective study of all the THM patients treated at our institute between May 1987 and June 2022. The demographic data, signs and symptoms, surgical notes, postoperative details, and radiotherapy were gathered retrospectively. Survival analysis was done with Kaplan-Meier tests along with predictors of the extent of resection as well as recurrence. A total of 39 patients qualified to be included in the study, with 10 male patients (male:female 1:2.9) and an average age of 50.8 years. The average follow-up duration was 75.9 months. Simpson's grade 2 excision was achieved in 19 (48.7%) patients, followed by Simpson's grade 3 excision in 17 patients (43.6%). Progression-free survival in subtotal resection was 60 months, and 100 months in gross total resection. Statistically, the extent of the resection was determined by the involvement of sinuses/torcula and the number of quadrants involved around torcula. A total of 16 patients received radiosurgery for the residual or small reccurrence of the lesion. Follow-up revealed reccurrence in 5 cases. Torcular meningiomas are relatively uncommon, described in few reports, and represent a therapeutic dilemma. Though some experts recommend complete removal of tumor and reconstruction of the sinus, others suggest maximum safe resection, followed by radiosurgery. The present study reflects reasonable control of the residual lesion with radiosurgery after maximum safe resection. [ABSTRACT FROM AUTHOR]

Medically refractory cases of trigeminal neuralgia often require treatment escalation. Surgical options include microvascular decompression and percutaneous ablation. This paper provides a bibliometric analysis of the most influential articles on the surgical management of trigeminal neuralgia. The Web of Science database was queried to identify the top 100 cited articles concerning surgical treatment of trigeminal neuralgia. The search terms used included ALL=(("trigeminal neuralgia" OR "tic douloureux" OR "Fothergill's disease" OR "Trifacial neuralgia") AND ("surgical treatment" OR "surgical management" OR "surgery" OR "neurosurgery") NOT ("radiosurgery" OR "gamma knife")). The extracted variables included the first and senior author names, journal, publication year, institution, and surgical modality. Our bibliometric search yielded 2104 studies, with 41,502 citations overall. Within the top 100 articles, Zakrzewska had the most first author papers (n = 5), and Burchiel had the most senior author papers (n = 6). The Massachusetts General Hospital was the most represented institution (n = 5). The United States was the most represented country (51%). Microvascular decompression was the most studied surgical strategy (51%), followed by percutaneous radiofrequency coagulation (9%), balloon/nerve compression (7%), and glycerol rhizolysis (7%). Some studies assessed multiple treatment modalities (22%). The types of studies included retrospective articles (58%), prospective articles (26%), reviews (10%), anatomic studies (2%), and basic science (1%). Neurosurgery (35%) and the Journal of Neurosurgery (33%) were the most represented journals. The current literature consists of retrospective reviews and mostly describes microvascular decompression for trigeminal neuralgia. Future studies should include further characterization of other surgical modalities such as percutaneous radiofrequency thermocoagulation, glycerol injection, and balloon compression. [ABSTRACT FROM AUTHOR]

Trigeminal neuralgia is a facial pain syndrome most commonly caused by a neurovascular compression (NVC) of the trigeminal nerve. Microvascular decompression (MVD) is the most durable surgical treatment; however, patients without an NVC are not candidates for this procedure. Alternative treatments such as percutaneous rhizotomy and radiosurgery are effective but with higher recurrence rates. Internal neurolysis (IN) is a less frequently used procedure that aims to provide long-term relief to patients without NVC. We present the surgical techniques for IN developed at our institution. We also discuss the technical nuances related to nerve consistency and present a new classification based on these findings. We provide pain and numbness outcomes for our cohort of patients stratified by the extent of neurolysis and nerve consistency. Patients with medically intractable trigeminal neuralgia eligible for posterior fossa exploration are eligible for MVD and possible IN. If no NVC or a mild NVC is encountered, IN is performed. We have divided the procedure into 4 main steps: opening the outer connective sheath, fascicular dissection, inside-out dissection and the fascicular irrigation technique. Trigeminal nerve consistency has been classified into 3 main types: type 1 is soft and friable; type 2 is intermediate consistency and ideal for neurolysis; and type 3 is firm and presents a more challenging dissection. In the absence of microvascular compression, we advocate for a thorough neurolysis using the techniques described in our article. [ABSTRACT FROM AUTHOR]

In Africa, epilepsy is a real burden. Temporal lobe epilepsy is the most common drug-resistant focal epilepsy disorder, and temporal lobectomy is the most common effective treatment for patients with drug-resistant epilepsy. We aim to highlight the Moroccan experience in epilepsy surgery and to ascertain its long-term outcome. Through the results of surgical treatment in our series, we hope to raise awareness of the need for epilepsy surgery in Africa and contribute to its development. We present a retrospective study of 132 patients who underwent surgery for epilepsy from January 2005 to December 2021 at our institution. The presurgical evaluation was based on clinical screening, interictal electroencephalography, video-electroencephalography, neuropsychological tests, magnetic resonance imaging, and positron emission tomography in some cases. Data are presented as the median and ranges. For all analyses, P values <0.05 were considered statistically significant. Our series includes 132 patients (69 males; 52.27%); the median age at surgery was 24 years (range, 1–64). One hundred and fifteen patients (87%) were operated on for temporal lobe epilepsy, of whom 98 (85%) had anterior temporal lobectomy and 17 (15%) had lesionectomy. Seventeen patients (13%) were operated on for extratemporal epilepsy, of whom 4 had lesionectomy, 7 functional hemispherotomy, and 5 Gamma Knife stereotactic radiosurgery. Our postoperative outcomes 3 months after surgery found 113 patients (85.6%) seizure-free (Engel class I), 16 with Engel class II (12.1%), and 3 with Engel class III (2.3%) in temporal lobe epilepsy. In extratemporal lobe epilepsy, 12 patients (70.5%) showed Engel class I, seizure-free, 4 Engel class II (23.5%), and 1 Engel class III (6%). These results confirm that most patients with drug-resistant epilepsy may benefit from surgical treatment without submitting to preoperative invasive explorations. This finding should help develop epilepsy surgery widely in Africa. [ABSTRACT FROM AUTHOR]

Stereotactic radiosurgery (SRS) and recently, hypofractionated radiosurgery (hSRS) are increasingly utilized as treatment for vestibular schwannomas (VS). We performed a meta-analysis of literature comparing these modalities. The PubMed database of articles was searched for studies that compared SRS and hSRS in patients with VS. Variables analyzed include tumor control, hearing preservation, facial nerve preservation, trigeminal nerve preservation, and total complications. Heterogeneity across the studies was gauged using Higgins's inconsistency index. Funnel plots and Egger's regression intercept test were used to address the publication bias. Thirteen studies that satisfied the search criteria were selected for meta-analysis. The studies identified in our study included 353 SRS and 511 hSRS-treated patients. Analysis of heterogeneity showed that hSRS is employed for relatively larger tumor sizes in comparison to SRS. Pooled meta-analysis estimates showed no significant differences between SRS and hSRS in terms of tumor control (odds ratio [OR], 0.620; 95% confidence interval [CI], 0.21–1.86, P = 0.39), hearing preservation (OR, 1.07; 95% CI, 0.59–1.93, P = 0.83), facial nerve preservation (OR, 0.53; 5% CI, 0.23–1.21, P = 0.13), or trigeminal nerve preservation (OR, 0.67; 95% CI, 0.24–1.89, P = 0.49) at a mean follow-up of 39 months. Statistically significant heterogeneity was found across the studies only for tumor diameter (Higgins's inconsistency index = 65.69%, P = 0.003) but not for other variables. Meta-analysis of thirteen studies comparing SRS and hSRS as treatment for VS showed comparable tumor control, hearing preservation, facial nerve preservation, and trigeminal nerve preservation. [ABSTRACT FROM AUTHOR]

While postoperative resection cavity radiosurgery (post-SRS) is an accepted treatment paradigm for brain metastasis (BM) patients who undergo surgical resection, there is emerging interest in preoperative radiosurgery (pre-SRS) followed by surgical resection as an alternative treatment paradigm. Here, we performed a meta-analysis of the available literature on this matter. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a search of all studies evaluating pre-SRS and post-SRS was completed. Local recurrence (LR), overall survival (OS), radiation necrosis (RN), and leptomeningeal disease (LMD) were evaluated from the available data. Moderator analysis and pooled effect sizes were performed using a proportional meta-analysis with R using the metafor package. Statistics are presented as mean [95% confidence interval]. We identified 6 pre-SRS and 33 post-SRS studies with comparable tumor volume (4.5–17.6 cm3). There were significant differences in the pooled estimates of LR and LMD, favoring pre-SRS over post-SRS. Pooled aggregate for LR was 11.0% [4.9–13.7] and 17.5% [15.1–19.9] for pre- and post-SRS studies (P = 0.014). Similarly, pooled estimates of LMD favored pre-SRS, 4.4% [2.6–6.2], relative to post-SRS, 12.3% [8.9–15.7] (P = 0.019). In contrast, no significant differences were found in terms of RN and OS. Pooled estimates for RN were 6.4% [3.1–9.6] and 8.9% [6.3–11.6] for pre- and post-SRS studies (P = 0.393), respectively. Pooled estimates for OS were 60.2% [55.8–64.6] and 60.5% [56.9–64.0] for pre- and post-SRS studies (P = 0.974). This meta-analysis supports further exploration of pre-SRS as a strategy for the treatment of BM. [ABSTRACT FROM AUTHOR]

Radiation necrosis (RN) is a long-term side effect of Gamma Knife stereotactic radiosurgery that may require surgical intervention. Pentoxifylline and vitamin E have previously been shown to be effective in the treatment of RN in the published literature, but there are no data on the prophylactic use of these molecules or, more importantly, whether prophylaxis is required. The iatrogenic RN model included 50 Sprague–Dawley rats of both sexes. There were 7 treatment subgroups established. Gamma–Plan 8.32 was used to plan after magnetic resonance scans were performed in a specially designed frame. The injection doses used in the treatment groups were vitamin E (30 mg/kg/day in a single dose) and pentoxifylline (50 mg/kg/day in 2 doses). Control magnetic resonance scans were performed at the end of a 16-week treatment, and the subjects were decapitated for pathological evaluations. The intensity of hypoxia - inducible factor 1α immunoreactivity is statistically significantly lower in the therapeutic vitamin E, prophylactic pentoxifylline and vitamin E, and therapeutic pentoxifylline and vitamin E groups than in the other groups. Similarly, the intensity of vascular endothelial growth factor immunoreactivity was reduced in the therapeutic vitamin E and prophylactic pentoxifylline and vitamin E treatment modality groups. When compared with other groups, the therapeutic pentoxifylline group had significantly fewer vascular endothelial growth factor-immunoreactive cells in the perinecrotic area, with an accompanying decreased contrast enhancement pattern. Both vitamin E and pentoxifylline are effective for the treatment and/or restriction of RN, either alone or in combination. The use of these molecules as a preventive measure did not outperform the therapeutic treatment. [ABSTRACT FROM AUTHOR]

The use of radiotherapy (RT) for the treatment of vestibulocochlear schwannomas is standard in patients with type 2 neurofibromatosis (NF2). In the general population, fractionated RT (FRT) can achieve good results compared to single-dose radiosurgery (SRS). We aimed to assess whether this is true for NF2 patients as well. This retrospective cohort study included 34 patients and 54 lesions treated between 2010 and 2023 in a single university hospital. Thirty-four patient charts were assessed. The median follow-up was 62.6 months (range, 7.1–135.8 months). Lesion size (median larger diameter, 2.5 cm) was correlated with the use of FRT (P > 0.001). Younger age also was correlated with FRT (P = 0.006). Median overall survival and progression-free survival (PFS) were not reached. The overall control rate was 76.5%, and the mean PFS was 49.8 months, compared with. 90.5% and 57.2 months, respectively, for SRS and 66.7% and 44.9 months, respectively, for FRT. There were no differences between the 2 groups in hearing loss, tinnitus, and facial palsy. In the NF2 population, FRT may yield worse control rates than SRS. Whenever possible, it is preferable to not fractionate treatment for these patients. Nevertheless, the FRT results were still good. More and larger prospective trials are warranted. [ABSTRACT FROM AUTHOR]

Choroid plexus papillomas (CPPs) are rare intraventricular brain tumors derived from the epithelium of the choroid plexus. Gross total resection has traditionally been considered curative, but residual tumor or recurrence remains possible. Stereotactic radiosurgery (SRS) has become a more important strategy for subtotally resected and recurrent tumors. The evidence-based rationale of SRS treatment for residual or recurrent CPP in adult patients is still lacking because of the rarity of the disease. We retrospectively reviewed the cases of histopathologically confirmed patients with residual or recurrent CPP treated with SRS at our institute in the adult population between 2005 and 2022. Three patients, with 5 lesions, were identified, with a median age of 63 years. Patients presented initially with hydrocephalus-related symptoms, although ventriculomegaly was noted in only 1 patient radiographically. The tumor location was most commonly in the fourth ventricle or along the foramen of Luschka. Treatment was delivered in a single fraction in 4 lesions and in 3 fractions in 1 patient. The median follow-up was 26 months. The local tumor control rate for the lesions was 80%. One patient developed a new lesion outside the SRS field, and 1 lesion developed progression without the need for subsequent treatment. There was no significant shrinkage of the lesions radiographically. None of the patients showed radiation-related adverse events. No patients required surgical management after SRS treatment at our institution. Based on the literature review, our case series was the second largest retrospective series from a single institution on SRS for recurrent or residual CPP. SRS for patients with recurrent or residual CPP was a safe and effective treatment modality in this case series. Larger studies are encouraged to validate the role of SRS in the treatment of recurrent or residual CPP. [ABSTRACT FROM AUTHOR]

To characterize and classify the location of recurrence in surgically resected World Health Organization (WHO) grade 2 intracranial meningiomas that did not receive adjuvant radiation and compare the recurrence pattern of those who underwent gross total resection (GTR) versus subtotal resection (STR). We performed a retrospective review of patients who underwent surgical resection of a newly diagnosed WHO grade 2 meningioma at our institution between 1996 and 2019. Patients who were observed postoperatively without adjuvant radiation and subsequently developed a recurrence were included in the study. All patients who received adjuvant therapy were excluded. Recurrence was defined as any evidence of radiographic progression on postoperative surveillance magnetic resonance imaging. Location of recurrence was categorized as follows: 1) central–growth observed inside the area of the previously resected tumor more than 1 cm inside the original tumor margin; 2) marginal–growth observed within 1 cm (inside or outside) of the original tumor margin; and 3) remote–growth observed >1 cm outside the original tumor margin. Patterns of recurrence were evaluated by 2 observers after coregistering preoperative and postoperative magnetic resonance imaging, and any differences were reconciled by discussion. A total of 22 patients matched the inclusion criteria. Twelve (55%) underwent GTR, and 10 (45%) underwent STR. In 12 patients in whom GTR was achieved, the mean preoperative tumor volume was 50.6 cm3, with 5 (41.7%) in a skull base location. The average time to recurrence for these tumors was 22.7 months, with a mean recurrent tumor volume of 9.0 cm3. Ten patients (83.3%) had central recurrence, 11 patients (91.7%) had marginal recurrence, and only 4 patients (33.3%) had remote recurrence. In 10 patients in whom STR was achieved, mean preoperative tumor volume was 44.8 cm3, with 7 (70.0%) in a skull base location. The average time to recurrence for these tumors was 23.0 months, with a mean recurrent tumor volume of 21.8 cm3. Of these 10 patients, 9 (90.0%) had central recurrence, all 10 (100.0%) had marginal recurrence, and only 4 (40.0%) patients had remote recurrence. The present study evaluating patterns of recurrence for WHO grade 2 meningiomas after surgical resection (GTR or STR) showed that recurrence occurred centrally and/or at the original tumor margin, with only a few recurring >1 cm outside the original tumor margin. The results of this study suggest that treatment, whether initial surgical resection or adjuvant radiation, may benefit from including at least a 1-cm dural margin when safe, to optimize tumor control, but further clinical study is needed. [ABSTRACT FROM AUTHOR]

Brain metastases (BMs) are the most common expansive intracranial lesions in adults. Approximately 50% of patients diagnosed with new BMs will have >1 BM at the diagnosis. We report our experience with BMs treated with Leksell Gamma Knife stereotactic radiosurgery (GKSR) and evaluate the outcomes. Patients treated by GKSR in our institution between 2008 and 2021 for BMs were evaluated retrospectively. A total of 205 patients (56.6% women) were included, with a median age of 59 years (range, 25–83 years). The breast (n = 85; 42.5%) and lung (n = 76; 38%) were the most common original locations for the primary tumors. Of the 205 patients, 103 (50.3%) had a single BM and 102 (49.7%) had ≥2 BMs. The median number of multiple BMs treated was 4 (range, 2–43). The mean overall survival (OS) time was 6.00 months (95% confidence interval [CI], 5.07–6.93 months) for all BMs. The median rate of tumor control after radiosurgery was 65% (range, 20%–99%) during a median follow-up of 6.00 months (95% CI, 3–84 months). In the overall population, the 1-, 2-, and 5-year OS rate was 37.55%, 25.12%, and 18.51%, respectively. The mean OS time was longer for those with multiple BMs than for those with a single BM (mean, 10 months [95% CI, 6.67–13.33 months] vs. mean, 5 months [95% CI, 4.21–5.70 months]; P = 0.03). Retreatment, tumor stability (control), and progression influenced the OS of patients with BMs, whether single or multiple (P < 0.001). GKSR provides good results in terms of OS and better quality of life for patients with BMs, whether single or multiple. Tumor stability and retreatment influenced the OS of patients with BMs. [ABSTRACT FROM AUTHOR]

The best management for AVM, particularly high-grade ones and those that have been ruptured before, is still unknown. Data from prospective data lacks support for the best approach. We retrospectively review patients with AVM at a single institution that were treated with radiation or a combination of radiation and embolization. These patients were divided into two groups based on radiation fractionation: SRS and fSRS. One-hundred and thirty-five (135) patients were first assessed and 121 met study criteria. Mean age at treatment was 30.5 years, and most patients were male. The groups were otherwise balanced, except for nidus size. SRS group had smaller lesions (P > 0.005). SRS correlates to better chance of nidus occlusion and lesser chance of retreatment. Complications such as radionecrosis (5%) and bleeding after nidus occlusion (1 patient) were rare. Stereotactic radiosurgery plays an important role on the treatment of AVM. Whenever possible, SRS should be preferred. Data from prospective trials about larger and previously ruptured lesions are needed. [ABSTRACT FROM AUTHOR]

Patients with brainstem metastases (BSMs) have minimal surgical options due to high-risk anatomy. To review our efficacy treating BSM using Gamma Knife stereotactic radiosurgery (SRS), we compared results on the basis of the utilization of mask-fixation (MF) or frame-fixation (FF). Data were retrospectively collected for 32 patients. Follow-up data for 49 lesions were analyzed for local control rate (LCR) and objective response rate (ORR). Primary cancers included lung, breast, and melanoma; most lesions were pontine. MF was used in 18 patients. Average tumor volume was 0.99 cm3 (0.005–13.3 cm3). Thirty-nine lesions were treated with single-fraction 16 Gy. Ten lesions were treated in 3–5 fractions with mean dose of 22.5 Gy. Mean follow-up was 14.2 months (1.2–48.2 months). One-year LCR was 94.7%. ORR at last follow-up did not differ between MF and FF (P = 0.81). Average reduction of lesion volume at 6 and 12 months did not differ between MF and FF (64% vs. 45%, P = 0.77; 70% vs. 77%, P = 0.78). Failure occurred in a pontine colorectal cancer metastasis mask-immobilized for treatment with 14 Gy. SRS for BSM achieved high LCR despite variability in tumor size and histology with no significant difference between MF and FF. Although trials have historically excluded patients with BSM, our data support SRS as a safe and efficacious treatment. This is the first study showing that MF provides equivalent, successful outcomes when compared with FF for patients with BSM. [ABSTRACT FROM AUTHOR]

The trend of practice pattern and impact on health care utilization for surgery and radiation therapy (RT) in patients with glomus jugulare tumors (GJTs) is not well defined. The IBM (Armonk, NY) MarketScan database was queried using the ICD-9/10 and CPT 4th edition, 2000–2020. We included patients ≥18 years of age who underwent either surgery or RT with at-least 1-year follow-up. We compared the health care utilization at 3-month, 6-month, and 1-year follow up using the inverse probability of treatment weight technique. A cohort of 333 patients was identified. Of these, 72.7% (n = 242) underwent RT and 27.3% (n = 91) underwent surgery. RT use increased from 2002–2004 (50%) to 2017–2019 (91%). Patients in the surgery cohort were younger (median age 49 vs. 56 years, P < 0.0001) and had a higher 3+ comorbidity index (34% vs. 30%, P = 0.43) compared with patients in the RT cohort. Patients who underwent surgery had higher complications at index hospitalization (22% vs. 6%, P < 0.0001) and at 30 days (14% vs. 5%, P = 0.0042). No difference in combined index and 6- or 12-month payments were noted (6-months: surgery, $66m108, RT: $43m509, P = 0.1034; 12-months: surgery, $73,259, RT: $51,576, P = 0.1817). Only 4% of patients who had initial RT underwent RT and none underwent surgery at 12 months, whereas 6% of patients who had initial surgery underwent RT and 2% underwent surgery at 12 months. RT plays an increasingly important role in the treatment for patients with GJTs, with fewer complications and a comparable health care utilization at 1 year. [ABSTRACT FROM AUTHOR]

Spetzler-Martin (SM) grade III arteriovenous malformations (AVMs) show angioarchitecture heterogeneity and lack a clearly defined treatment strategy. This study aims to evaluate outcomes after treatment of SM grade III AVMs with Gamma Knife radiosurgery (GKRS). A single-institution retrospective analysis was conducted of 307 patients with SM grade III AVMs undergoing GKRS between October 2006 and December 2020 with follow-up times of at least 24 months. SM grade III AVMs were classified into 4 subtypes: IIIA (S1E1V1), IIIB (S2E0V1), subtype IIIC (S2E1V0), and IIID (S3E0V0). Over a median follow-up time of 50.3 months, complete AVM obliteration was achieved in 211 patients (68.7%). Complete obliteration rates in subtypes IIIA, IIIB, IIIC, and IIID were 80.8%, 55.4%, 53.4%, and 25.0%, respectively. Annual post-GKRS hemorrhage risk was 0.8%. Significant radiosurgery-induced imaging changes occurred in 7 patients (2.3%). Three variables were identified as predictors of obliteration in final forward stepwise regression models, including volume of AVM (B = –0.011; P < 0.001), age (B = –0.004; P = 0.024), and previous AVM hemorrhage (B = 0.187; P = 0.077). GKRS is a safe and effective treatment for SM grade III AVMs, particularly subtype IIIA (S1E1V1). AVM volume is the key predictor of post-GKRS obliteration. [ABSTRACT FROM AUTHOR]

Tumor-related trigeminal neuralgia (TN) is a challenging condition to manage that is commonly treated by surgical resection of the tumor. Stereotactic radiosurgery targeting the tumor is used to control pain and tumor growth in patients unsuitable for surgery. Stereotactic radiosurgery targeting the trigeminal nerve has been explored as a viable treatment for patients with tumor-related TN who are unsuitable for surgical removal of the tumor or whose pain is refractory to radiation therapy targeting the tumor. Information regarding the efficacy of this procedure is limited to only a few studies. We report the outcomes of Leskell Gamma Knife radiosurgery (GKRS) targeting the trigeminal nerve for tumor-related TN from a case series. A retrospective review of our GKRS database identified 6 patients with unilateral tumor-related TN treated with GKRS targeting the trigeminal nerve between 2014 and 2020. Five patients had undergone previous radiation therapy targeting the tumor. Facial pain and sensory function were evaluated using the Barrow Neurological Institute scales. Three patients achieved a Barrow Neurological Institute score of IIIb or better, indicating pain reduction, within a mean period of 4.3 months after GKRS. The maximum dose for GKRS ranged from 80 to 88 Gy. Pain recurred in 1 patient at 64 months after GKRS. No patient developed permanent facial sensory disturbances. No adverse event was recorded. GKRS targeting the trigeminal nerve could be a safe and effective treatment for a subset of patients with tumor-related TN who are unsuitable for surgical removal of the tumor or whose pain is refractory to radiation therapy targeting the tumor. [ABSTRACT FROM AUTHOR]

Intramedullary spinal arteriovenous malformation (ISAVM, glomus type) is a type of spinal cord arteriovenous malformation, which is a rare disease known often to have a complex vascular supply interfering with that of the spinal cord, and is in complex anatomical relations with cord structures and nerve roots. Though microsurgical and endovascular treatment has mainly been the standard options, in high-risk cases with these treatments, stereotactic radiotherapy (SRT) might be the option of choice. We retrospectively reviewed 10 consecutive patients with ISAVM who received SRT using CyberKnife at the Japanese Red Cross Medical Center (Tokyo, Japan) from January 2011 to March 2022. No case in this series suffered from hemorrhage after applying SRT. One case experienced neurological impairment 10 years after SRT, which we attributed to venous congestion due to the remaining lesion. No case of radiation myelopathy was observed in this series. In one case, the nidus volume reduction and loss of flow voids were obvious, though improvement in the neurological outcome was not apparent. No radiological changes were observed in the other 9 patients. Even in lesions without radiological changes, no hemorrhagic events were observed for an average period of 4 years. SRT may be a feasible option in treating ISAVM, especially for lesions in which microsurgical resection and endovascular treatment are inapplicable. To ascertain the safety and efficacy of this approach, further studies with more patients and longer follow-up is required. [ABSTRACT FROM AUTHOR]

To compare the impact of different management strategies on diagnosis of new-onset mental health disorders (MHDs) in patients with vestibular schwannoma (VS) and health care utilization at 1-year follow-up. MarketScan databases were queried using the International Classification of Diseases, Ninth Revision and Tenth Revision and Current Procedural Terminology, Fourth Edition, 2000–2020. We included patients ≥18 years old with a diagnosis of VS who underwent clinical observation, surgery, or stereotactic radiosurgery (SRS) with at least 1 year of follow-up. We looked at health care outcomes and MHDs at 3-month, 6-month, and 1-year follow-up. The database search identified 23,376 patients. Of these, 94.2% (n = 22,041) were managed conservatively with clinical observation at the initial diagnosis, and 2% (n = 466) underwent surgery. The surgery cohort had the highest incidence of new-onset MHDs followed by SRS and clinical observation cohorts at 3 months (surgery: 17%; SRS: 12%; clinical observation: 7%), 6 months (surgery: 20%; SRS: 16%; clinical observation: 10%), and 12 months (surgery: 27%; SRS: 23%; clinical observation: 16%) (P < 0.0001). The median difference in combined payments between patients with and without MHDs was highest in the surgery cohort followed by SRS and clinical observation cohorts at all time points (12 months: surgery: $14,469; SRS: $10,557; clinical observation: $6439; P = 0.0002). Compared with clinical observation only, patients who underwent surgery for VS were 2 times more likely and patients who underwent SRS were 1.5 times more likely to develop MHDs with corresponding increase in health care utilization at 1-year follow-up. [ABSTRACT FROM AUTHOR]

Recurrent Cushing disease (CD) is characterized by the reappearance of clinical and hormonal aspects of hypercortisolism that occur more than 6 months after an initial post-treatment remission. We performed a systematic review and meta-analysis to synthesize the evidence about remission and complication rates after transsphenoidal surgery (TSS) radiotherapy (RT) and medical therapy (MT) in recurrent CD patients. A quantitative systematic review was performed. Article selection was performed by searching MEDLINE (using PubMed), and Cochrane electronic bibliographic databases through 2020. We noted 61 articles described therapeutic management of recurrent CD patients with representative outcome. A total of 723 patients received different therapeutic modality for their recurrent CD. The remission rates were 0.65 (95% confidence interval [CI] 0.60–0.70), 0.57 (95% CI 0.51–0.63), and 0.75 (95% CI 0.60–0.86) in the TSS, RT, and MT subgroups, respectively. The total remission rate after therapeutic approaches on recurrent CD patients was 0.64 (95% CI 0.60–0.68). A test for subgroup differences revealed there was a statistically significant difference between different subgroups (P = 0.01). The post hoc test showed that in comparison with RT, TSS (P = 0.0344) and MT (P = 0.0149) had a higher rate of remission. However, there was no statistically significant difference between separate therapeutic modalities in terms of complications including diabetes insipidus (P = 1.0) and hypopituitarism (P = 0.28). Compared MT and TSS, RT has a statistically lower rate of remission. Although there is robust superiority of surgery over RT, interpretation of MT data must considered with caution due to the small number of included cases and wide CI range. [ABSTRACT FROM AUTHOR]

Stereotactic radiosurgery (SRS) presents as a good treatment option for smaller, deep-seated brain metastases (BMs). This study aims to determine predictors of SRS failure for patients with non-small cell lung cancer BMs. This was a retrospective study of single non-small cell lung cancer BMs treated using SRS. We included patients >18 years with a single, previously untreated lesion. Primary outcome was treatment failure, defined as BMs dimension increase above the initial values. Demographic, clinical, and radiological data were collected to study potential predictors of treatment failure. Worse rates of progression-free survival (PFS) were associated with heterogeneous contrast enhancement (18.1 ± 4.1 vs. 41.9 ± 4 months; P < 0.001). Better rates of PFS were associated with volumes <1.06 cm3 (log-rank; P = 0.001). Graded prognostic assessment was significantly associated with survival at 120 months (log-rank; P < 0.001). Karnofsky Performance Scale was evaluated in 3 strata: 90–100, 80, and ≤70. Mean survival rates for these strata were 31.8 ± 3.9, 10.6 ± 2.2, and 9.8 ± 2.3 months, respectively (log-rank; P < 0.001). There were no differences regarding presence of extracranial metastases, age, or lesion location. A multivariable logistic regression found that volume <1.06 cm3 was associated with higher survival rates at 10 years (odds ratio: 3.2, 95% confidence interval: 1.3–8.0). Contrast-homogeneous metastases and lesions <1.06 cm3 are associated with better rates of PFS. Karnofsky Performance Scale and graded prognostic assessment were associated with more favorable survival rates after 10 years. Volume <1.06 cm3 was the only significant predictor of survival in the multivariable analysis. [ABSTRACT FROM AUTHOR]

To recalculate biological effective dose values (BED) for radio-surgical treatments of acoustic neuroma from a previous study. BEDs values were previously overestimated by only using beam-on times in calculations, so excluding the important beam-off-times (when deoxyribonucleic acid repair continues) which contribute to the overall treatment time. Simple BED estimations using a mono-exponential approximation may not always be appropriate but if used should include overall treatment time. Time intervals between isocenters were estimated. These were especially important for the Gamma Knife Model 4C cases since manual changes significantly increase overall treatment times. Individual treatment parameters, such as iso-center number, beam-on-time, and beam-off-time, were then used to calculate BED values using a more appropriate bi-exponential model that includes fast and slow components of DNA damage repair over a wider time range. The revised BED estimates differed significantly from previously published values. The overestimates of BED, obtained using beam-on-time only, varied from 0%–40.3%. BED subclasses, each with a BED range of 5 Gy 2.47 , indicated that revised values were consistently reduced when compared with originally quoted values, especially for 4C compared with Perfexion cases. Furthermore, subdivision of 4C cases by collimator number further emphasized the impact of scheduled gap times on BED. Further analysis demonstrated important limitations of the mono-exponential model. Target volume was a major confounding factor in the interpretation of the results of this study. BED values should be estimated by including beam-on and beam-off times. Suggestions are provided for more accurate BED estimations in future studies. [ABSTRACT FROM AUTHOR]

Management of large vestibular schwannoma (VS) is controversial. Surgery has historically been the treatment of choice, but emerging literature suggests that definitive stereotactic radiosurgery is feasible. We report our institutional experience of control and morbidity outcomes treating Koos grade 3–4 VS with Gamma Knife radiosurgery (GKRS). An institutional review board–approved database compiled outcomes of Koos grade 3–4 VS treated by GKRS from March 2014 to January 2021 with >6 months' follow-up. Baseline symptoms per Common Terminology Criteria for Adverse Events definitions were recorded. Control rates, toxicities, and post-treatment volumetric changes were analyzed. Aggregate impairment scores (AIs) were defined by the sum of relevant Common Terminology Criteria for Adverse Events grades to categorize symptomatic burdens. Baseline and post-treatment AIs were tested for association with definitive versus adjuvant strategies. In total, 34 patients with Koos grade 3–4 VS were identified, 19 treated with definitive GKRS (GKRS-D) and 15 with adjuvant GKRS (GKRS-A). Median follow-up was 34.2 months for GKRS-D and 48.8 months for GKRS-A. Patients who received GKRS-A had greater AIs at presentation (3.73 vs. 2.11, P = 0.017). Irrespective of treatment approach, tumor control rates were 100% without instances of brainstem necrosis or shunt placement. Six of 19 patients who received GKRS-D had improved post-treatment AI, and 63% of patients who received GKRS-D and 66% of patients who received GKRS-A had tumor shrinkage >20%. In well-selected patients with Koos grade 3–4 VS, definitive stereotactic radiosurgery may be an appropriate strategy with excellent control and minimal toxicity. Our data suggest that the need for surgical decompression should be considered based on pretreatment symptom burden rather than tumor size. [ABSTRACT FROM AUTHOR]

This study was conducted with the aim to estimate long-term tumor control and hearing preservation rates in patients with neurofibromatosis 2 (NF2)-related vestibular schwannoma (VS), document retreatment success rate, and assess the associated predictive factors. This was a retrospective analysis of patients with NF2-associated VS who underwent Gamma Knife radiosurgery (GKRS) between 2009 and 2020 and had a minimum follow-up of 1 year. Loss of tumor control was defined as greater than 10% increase in volume in more than one follow-up imaging or the need for retreatment in the form of repeat GKRS or surgery. The Kaplan–Meier method was used to evaluate actuarial tumor control and hearing preservation rates. In total, 85 patients with 133 VSs were included in the study. The mean age was 29.8 years. In total, 57 tumors showed tumor regression, 35 showed stable disease, and 23 progressed in size at last follow up. Actuarial tumor control rates after 1, 3, 5, and 9 years were 95%, 79%, 75%, and 55%, respectively, with overall tumor control rate being 85%. Hearing worsened in 39 patients, and facial nerve dysfunction occurred in 4 patients. Five tumors underwent retreatment with GKRS at a median duration of 27.6 months (19–36 months) following the first GKRS. This is the largest radiosurgical series of NF2-associated VS reported to date. GKRS provides a high rate of long-term local tumor control with a low risk of neurologic deprivation for patients with these tumors. The need for retreatment with GKRS, although low, is associated with good tumor control and lesser complications. [ABSTRACT FROM AUTHOR]

Although the short- to medium-term efficacy of Gamma Knife therapy for drug-resistant essential trigeminal neuralgia has been reported, long-term evaluations are limited. We evaluated patient data obtained at least 10 years post-treatment and examined the significance of this treatment using new end points. Among 249 consecutive patients with essential trigeminal neuralgia who were treated with Gamma Knife radiosurgery (retrogasserian target/4-mm single isocenter/90 Gy at 100%) at our institution between January 2003 and October 2011, 103 patients who were followed up for at least 10 years (mean, 174 [120–219] months) after treatment and whose data were amenable to accurate evaluation, were included in this retrospective study. Herein, we used the Barrow Neurological Institute (BNI) pain intensity scale as a clinical evaluation method for pain and the BNI numbness scale to evaluate complications (namely facial dysesthesia). The initial and final follow-up pain attack cessation (BNI pain intensity score I–IIIa) rate was 82.5% (85 of 103) and 58.2% (60 of 103), respectively. Furthermore, sensory impairment (BNI numbness score ≥ II) at the last follow-up was observed in 24.3% (25 of 103) of the cases, while very bothersome status (BNI numbness score IV) was observed in 2.9% of the cases. Gamma Knife radiosurgery for essential trigeminal neuralgia showed good therapeutic effects during long-term follow-up. Serious complications of significant concern in the short- to mid-term follow-up, resolved spontaneously. Therefore, the indications for treatment should be expanded to include patients who strongly desire Gamma Knife therapy. [ABSTRACT FROM AUTHOR]

Brain metastasis from thyroid cancer (TCBM) is extremely rare; thus, despite a good treatment outcome for thyroid cancer, TCBM has shown poor clinical outcomes. Considering the short survival and poor general condition of patients with TCBM, stereotactic radiosurgery may be preferred to achieve local control. A total of 25 patients with TCBM who underwent Gamma Knife radiosurgery (GKS) were initially included in this study; however, 3 patients were excluded because of a lack of data. There were 7 men (31.8%) and 15 women (68.2%) and the mean age was 63.7 years. The most common type of thyroid cancer histology was papillary carcinoma. Fourteen patients (63.6%) harbored single brain metastatic tumor and 8 (36.3%) had multiple brain metastatic tumors. The mean duration from thyroid cancer diagnosis to detection of brain metastasis was 7.7 years (range, 0–23 years). The median dose of radiation of GKS was 22 Gy (range, 18–25 Gy). There was no radiation-induced complication after GKS. The median overall survival (OS) was 15 months and the 1-year OS of patients with TCBM was 63%, the 2-year OS was 38%, and the 5-year OS was 28%. The 6-month progression-free survival (PFS) for local recurrence of TCBM was 90.4%, the 1-year PFS was 84%, and the 3-year PFS was 84%. GKS showed favorable local control for TCBM. However, the rate of distant brain metastasis was high and median survival of patients with TCBM was only 15 months. [ABSTRACT FROM AUTHOR]

A retrospective comparative analysis of the outcomes of gamma knife radiosurgery (GKRS) for brain metastases from uterine cervical carcinoma (CC) and endometrial carcinoma (EC), investigated the efficacy and prognostic factors for survival and local tumor control. Histopathological analysis was also performed. The authors retrospectively reviewed 61 patients with 260 tumors of CC and 73 patients with 302 tumors of EC who had undergone GKRS. The survival times after GKRS had no difference between CC and EC. Uncontrolled primary cancer was significant unfavorable factor. CC resulted in significantly higher neurological death and post-GKRS neurological deterioration. New lesions appeared intracranially after GKRS, with no significant difference between CC and EC. Local tumor control rates at 6, 12, and 24 months after GKRS were 90.0%, 86.6%, and 78.0% for CC and 92.2%, 87.9%, and 86.4% for EC. Primary cancer of CC, more than 7 cm3 volume, and prescription dose less than 20 Gy were significantly correlated in control failure. Local tumor control rates were significantly lower for squamous cell carcinoma in CC. No significant differences were found between histopathological subtypes of EC. This study established a relationship between the efficacy of GKRS for CC and EC brain metastases and the histopathological. Though, survival time after GKRS has no difference between CC and EC, CC was significantly higher neurogenic death and neurological deterioration after GKRS. Squamous cell carcinoma had a significantly lower rate of local tumor control among all CC, thereby resulting in CC having lower local tumor control than EC. [ABSTRACT FROM AUTHOR]

Brain metastases occur frequently in advanced melanoma and traditionally require surgery and radiation therapy. New evidence demonstrates that systemic therapies are effective for controlling metastatic melanoma brain metastases. This study evaluated outcomes after resection of melanoma brain metastases treated with systemic therapy, with or without focal radiotherapy. All patients received immunotherapy or BRAF/MEK inhibitors preoperatively or in the immediate 3 months postoperatively. Resection cavity failure, distant central nervous system progression, and adverse radiation effects were reported in the presence and absence of focal radiotherapy using the Kaplan-Meier method. Between 2011 and 2020, 37 resection cavities in 29 patients met criteria for analysis. Of lesions, 22 (59%) were treated with focal radiotherapy, and 15 (41%) were treated with targeted therapy or immunotherapy alone. The 12- and 24-month freedom from local recurrence was 64.8% (95% confidence interval [CI] 42.1%–99.8%) and 46.3% (95% CI 24.5%–87.5%), respectively, for systemic therapy alone and 93.3% (95% CI 81.5%–100%) at both time points for focal radiotherapy (P = 0.01). On univariate analysis, focal radiotherapy was the only significant factor associated with reduction of local recurrence risk (hazard ratio 0.10, 95% CI 0.01–0.85; P = 0.04). There were no significant differences in central nervous system progression-free survival or overall survival between patients who received systemic therapy plus focal radiotherapy compared with systemic therapy alone. BRAF mutation status was reviewed for either the brain metastasis (n = 9 patients, 31%) or the primary site (n = 20 patients, 69%), and patients harboring BRAF V600E mutations had worse progression-free survival (P = 0.043). Focal radiotherapy with systemic therapy for resected melanoma brain metastases significantly decreased resection cavity recurrence compared with systemic therapy alone. BRAF mutation status correlated with poorer outcomes. [ABSTRACT FROM AUTHOR]

The current treatment paradigm for intracranial arteriovenous malformations (AVMs) focuses on reducing the risk of intracranial hemorrhage using various therapeutic means including embolization, stereotactic radiosurgery (SRS), and microsurgical resection. To improve AVM obliteration rates with SRS, pre-radiosurgical embolization has been trialed in a number of studies to reduce the volume of the AVM nidus prior to radiosurgery. This study aimed to review the efficacy of pre-radiosurgical embolization in the pre-Onyx era compared to the current Onyx era. A systematic review was performed using PubMed to identify studies with 20 or more AVM patients, embolization material, and obliteration rates for both embolization + stereotactic radiosurgery (E+SRS) and SRS-only groups. Seventeen articles consisting of 1133 eligible patients were included in this study. A total of 914 (80.7%) patients underwent embolization prior to SRS. Onyx was used as the embolysate in 340 (37.2%) patients in the E+SRS cohorts. Mean obliteration rate for the embolized cohort was 46.9% versus 46.5% in the SRS-only cohort. When comparing obliteration rates based on embolysate material, obliteration rate was 42.1% with Onyx+SRS and 50.0% in the non-Onyx embolysate + SRS cohort. Onyx (ethylene vinyl-alcohol copolymer dissolved in dimethyl sulfoxide and suspended in micronized tantalum powder) has been increasingly used for the embolization of intracranial AVMs with increased success regarding its ease of use from a technical standpoint and performs similarly to other embolysate materials. [ABSTRACT FROM AUTHOR]

This study aims to assess efficacy of a 15-Gy margin dose in terms with the hypothesis that efficacy will be comparable with historical controls with fewer radiation-related side effects. Patients who received single-fraction stereotactic radiosurgery (SRS) for metastatic brain tumors (prescribed 1500 cGy with 2-mm planning tumor volume) at the University of Missouri Hospital between 2004 and 2018 with at least 3 months of follow-up were retrospectively reviewed. Demographics, lesion dimensions, concurrent therapy, and treatment history before SRS were assessed. Outcomes included local control, distant control, radiation-related changes, survival, repeat SRS or whole-brain radiation therapy, and side effects. Data from the literature were pooled for a meta-analysis. A total of 142 patients had at least 3 months of follow-up data available. The 12-month actual local control rate among these patients was 92% per tumor. The overall intracranial control rate was 66.9% per patient. Radiation-related side effects occurred in 32.4% of patients (n = 46), with some patients having more than 1 side effect. Radiation-related radiographic changes occurred in 48 lesions (10.6%) in 37 patients (26%). Pathologically confirmed radiation necrosis occurred in 19 lesions (4%) and in 18 patients (12.6%). Local and distant control rates for this population was comparable with historical controls. Side effects in the literature are inconsistently reported, so rigorous comparative analysis is not possible. A single-fraction radiosurgery margin dose of 15 Gy to the planning tumor volume can effectively provide local control and distant control and is comparable with historical controls, which use 18–25 Gy, with a good toxicity profile. [ABSTRACT FROM AUTHOR]

The effectiveness of gamma knife radiosurgery (GKRS) for the management of trigeminal schwannomas (TS) has been established. Although GKRS has been shown to inhibit tumor growth, the effect of GKRS on the symptoms caused by TS has not been sufficiently studied. In this study, symptomatic changes following GKRS for the management of symptomatic TS were investigated using long-term follow-up results. A retrospective analysis was performed on 32 patients with TS who underwent GKRS between May 1994 and December 2016. Clinical charts, radiographic results, and surgical records were reviewed. To evaluate whether symptoms improved after GKRS, patient demographics, GKRS profile, radiological tumor size change, and tumor location were analyzed. Tumor control after GKRS for symptomatic TS was 87%. The improvement rates for facial pain at 6, 12, and 24 months after GKRS were 46%, 72%, and 86%, respectively. For the same time intervals, facial hypesthesia improved by 12%, 46%, and 52%, respectively. Of the patients with diplopia, 17% had improved symptoms 12 months after GKRS, and 50% of the patients improved after 24 months. GKRS can be an effective treatment modality for TS tumor control and shows favorable results in improving TS-related symptom, especially facial pain. [ABSTRACT FROM AUTHOR]

To explore the impact of outflow patency on radiosurgical outcomes of lateral sinus dural arteriovenous fistulas (DAVFs). We retrospectively examined 83 lateral sinus DAVFs treated with Gamma Knife radiosurgery (GKRS) between 1995 and 2020. Two neuroradiologists blinded to the therapeutic outcomes served as imaging evaluators on pre-GKRS digital subtraction angiography and magnetic resonance images. The sinovenous outflow of lateral sinus DAVF was scored using combined conduit score (CCS), ranging from 0 (total occlusion) to 8 (full patency). The patients' follow-up magnetic resonance and digital subtraction angiography images were used to validate the radiosurgical outcomes (obliteration or non-obliteration) of lateral sinus DAVF. Cox regression and Kaplan–Meier analyses were performed to determine the correlations between the variables and outcomes. Among the 83 cases, 60 (72%) lateral sinus DAVFs achieved obliteration after a GKRS at a median latency period of 24.5 months. After adjustment for aggressive presentation, cortical venous reflux, straight sinus reflux, and optic nerve sheath enlargement, a CCS of >6 was independently associated with lateral sinus DAVF obliteration (hazard ratio: 2.335, P = 0.007). The estimated 36-month probabilities of obliteration were 80% versus 53.6% for lateral sinus DAVFs with a CCS of >6 versus ≤6. Lateral sinus DAVFs with a CCS of >6, indicating a nearly patent sinovenous outflow, were more likely to be obliterated after GKRS. Sinovenous outflow patency is a factor associated with therapeutic outcomes in radiosurgery for lateral sinus DAVFs. [ABSTRACT FROM AUTHOR]

There are 2 cardinal approaches for drug-resistant trigeminal neuralgia (TN), including microvascular decompression (MVD) and gamma knife surgery (GKS). This study aimed to compare the results of MVD versus GKS in the treatment of drug-resistant TN. The search strategy was formulated in accordance with PRISMA recommendations for publications retrieved from electronic databases, such as PubMed, Scopus, and web of science. Inclusion and exclusion criteria were examined for relevant research. The meta-analysis was conducted by combining data using odds ratios. Four papers were included in our study. 582 patients were treated with MVD, and 607 patients were treated with GKS for drug-resistant TN. Findings revealed that MVD related to higher rates of pain relief and lower rates of pain recurrence compared to GKS. It seems that GKS had lower post-procedural complications in our review. MVD and GKS both reduce pain in patients with drug-resistant TN, but MVD was superior to GKS in pain relief. Furthermore, recurrence rate was lower. Post-operative complications except facial numbness were higher in MVD. [ABSTRACT FROM AUTHOR]

Vestibular schwannomas are benign, slow-growing tumors that often reduce patient quality of life by compressing nearby nerves. Neurological function preservation is one of the indicators of treatment success, with hearing preservation being the most difficult to obtain. This paper provides a bibliometric analysis of hearing preservation in treating acoustic neuromas and a greater understanding of the most highly cited articles, which have enhanced our understanding of this topic. Key terms of "acoustic neuroma," "vestibular schwannoma," and "hearing preservation" were queried through Web of Science. Articles were sorted by citation frequency, and the top 100 articles were recorded for title, name of first author, journal title, year of publication, total number of citations (and associated rank), average number of citations per year, country of the first author's associated institution, and type of study. The top 100 cited articles were published from 1980 to 2014. The United States had the highest involvement as a country (55%), the University of Pittsburgh as an institution (13%), and The Journal of Neurosurgery as a publishing source (27%). Fourteen were reviews, and 86 were clinical papers. Of the 86, 73 were retrospective studies. Bibliometric analyses summarize and assess potential areas of strength and knowledge gaps within the literature. Studies on hearing preservation in vestibular schwannomas mostly consist of retrospective reviews that assess postoperative outcomes of microsurgery and radiosurgery. Prospective studies and novel treatment options for hearing preservation in vestibular schwannomas are needed to increase current literature diversity. [ABSTRACT FROM AUTHOR]

Gamma Knife (GK) stereotactic radiosurgery (SRS) is increasingly used as an initial treatment for patients with 10 or more brain metastases. However, the clinical and dosimetric consequences of this practice are not well established. We performed a single-institution, retrospective analysis of 30 patients who received Gamma Knife SRS for 10 or more brain metastases in 1 session. We utilized MIM Software to contour the whole brain and accumulated the doses from all treated lesions to determine the mean dose delivered to the whole brain. Patient outcomes were determined from chart review. Our cohort had a median number of 13 treated lesions (range 10–26 lesions) for a total of 427 treated lesions. The mean dose to the whole brain was determined to be 1.8 ± 0.91 Gy (range 0.70–3.8 Gy). The mean dose to the whole brain did not correlate with the number of treated lesions (Pearson r = 0.23, P = 0.21), but was closely associated with tumor volume (Pearson r = 0.95, P < 0.0001). There were no significant correlations between overall survival and number of lesions or aggregate tumor volume. Fourteen patients (47%) underwent additional SRS sessions and 6 patients (20%) underwent whole-brain radiotherapy with a median of 6.6 months (range 3.0–50 months) after SRS. Two patients (6.6%) developed grade 2 radionecrosis following SRS beyond earlier whole-brain radiotherapy. The mean dose to the whole brain in patients treated with Gamma Knife SRS for 10 or more brain metastases remained low with an acceptable rate of radionecrosis. This strategy allowed the majority of patients to avoid subsequent whole-brain radiotherapy. [ABSTRACT FROM AUTHOR]

Optic nerve sheath meningiomas (ONMs) are often managed with radiotherapy (RT) with the goal of achieving radiographic local control (LC) and preventing deterioration of visual acuity (VA). We aimed to perform a systematic review and meta-analysis of outcomes for patients with ONM treated with RT. The PICOS/PRISMA/MOOSE selection criteria were used to identify studies. Primary outcomes were stable or improved VA and radiographic LC at last follow-up. The secondary outcomes were incidences of radiation-induced retinopathy and xerophthalmia and stable or improved visual fields (VFs). Weighted random-effects meta-analyses using the DerSimonian and Laird methods were conducted to characterize effect sizes. Mixed-effects regression models were used to examine potential correlations between gross tumor volume (GTV) and outcomes. In total, 444 patients with ONM across 20 published studies were included. The estimated LC rate was 99.8% (95% confidence interval [CI], 98.3%–100%), and the estimated proportion of patients with stable or improved VA or VF was 89.7% (95% CI, 86.2%–92.4%) and 93.3% (95% CI, 89.5%–95.8%), respectively. Estimated incidences of radiation-induced retinopathy and xerophthalmia were 7.2% and 10.1%, respectively. GTV was significantly associated with VA (P = 0.014) with estimated VA rates of 96.4%, 91.4%, and 80.5% for GTVs of 2.0, 3.0, and 4.0 cm3, respectively. RT was well tolerated, with excellent LC achieved. Nearly 90% of patients noted either stability or improvement in VA and VF. Larger ONMs were associated with poorer VA. [ABSTRACT FROM AUTHOR]

Traditional Gamma Knife radiosurgery (GKRS) of brain arteriovenous malformations (AVMs) using digital subtraction angiography (DSA) requires head immobilization using a stereotactic frame. We describe our protocol of frameless GKRS using DSA while maintaining high spatial resolution for precision. This study is a retrospective review of patients with unruptured AVMs who underwent frameless GKRS. Magnetic resonance imaging and 3-dimensional DSA were obtained without a stereotactic frame for all patients. The imaging studies were merged for contouring of the AVM nidus. During GKRS treatment, patients were immobilized using an individually molded thermoplastic mask. Thirty-one patients were included in the analysis. The median age is 45.0 years (interquartile range [IQR]: 28.0–55.0). The median nidus size is 3.0 cm (IQR: 2.0–3.4). One patient had a Spetzler-Martin grade I, 11 had a grade II, 11 had a grade III, 6 had a grade IV, and 2 had a grade V AVM. Eleven patients underwent preradiosurgical embolization, 3 patients had previous microsurgical resection and/or embolization, and 1 patient had prior radiosurgery. The median administered dose was 20 Gy (IQR: 18.0–21.0). All patients completed their treatment with the planned radiation dose without complications. This is the first study that integrates DSA in the treatment planning of brain AVMs using GKRS without utilizing a stereotactic head frame. Frameless GKRS provides numerous advantages over frame-based techniques including improved patient experience and the capability of fractionation and thus expanding the eligibility of more AVMs for radiosurgery, while maintaining high spatial resolution of the AVM using angiography data. [ABSTRACT FROM AUTHOR]

Self-shielding gyroscopic radiosurgery (GRS) represents a technical innovation in the field of stereotactic radiosurgery. GRS does not require a radiation vault and is optimized for radiosurgical treatments. Reports on its usage are limited. We describe the first clinical experience of GRS at our institution to assess the application of GRS in the treatment of cranial tumors. Moreover, we perform a dosimetric comparison to robotic radiosurgery (RRS) with vestibular schwannoma (VS) GRS patients. Patients who were treated with GRS between July and November 2021 were included. Patient, tumor, and dosimetric characteristics were retrospectively summarized and analyzed. Forty-one patients with 48 intracranial tumors were included. Tumor entities mostly comprised VS, brain metastases, and meningiomas. The median prescription dose and isodose line were 13.5 Gy and 50.0% for benign neoplasia versus 20 Gy and 60.0% for malignant tumors, respectively. The mean planning target volume was 1.5 cubic centimeters. All patients received a single-fraction treatment without encountering any technical setup difficulties. Treatment plan comparisons with RRS revealed comparable plan characteristics, dose gradients, and organs at risk doses. Significant differences were detected concerning the new conformity index and number of monitor units per treatment (both P < 0.01). This case series provides more evidence on the usage of self-shielding GRS in the management of cranial tumors. Dosimetric comparisons for VS cases revealed mostly equivalent dosimetric characteristics to RRS. Further clinical and physical analyses for GRS are underway. [ABSTRACT FROM AUTHOR]

Gamma Knife radiosurgery (GKS) is a promising treatment option for meningioma. However, the incidence of peritumoral edema (PTE) following GKS has been reported to be 7%–38%. This study aimed to develop a predictive model for post-GKS PTE using a deep neural network (DNN) algorithm. Patients treated with GKS for meningioma between November 2012 and February 2020 at a single tertiary center were reviewed. The primary outcome was newly developed or aggravated PTE after GKS. Clinical data, including radiosurgical parameters, were collected, and imaging data obtained at the time of GKS were incorporated into the model using a 50-layered residual neural network, ResNet50. Consequently, the model efficiency was evaluated considering the accuracy and area under the receiver operating curve (AUC) values. A total of 202 patients were included in this study. The median tumor volume was 2.3 mL, and the median prescription dose was 13 Gy. PTE was observed before GKS in 22 patients. Post-GKS PTE was evident in 28 patients (13.9%), which further evolved to radiation necrosis in 5 patients. The accuracy and AUC values of the hybrid data model based on both clinical and imaging data were 0.725 and 0.701, respectively. The performance of the hybrid data model was superior to that of the other models based on clinical or image data only. The DNN-based model using both clinical and imaging data exhibited fair results in predicting post-GKS PTE in meningioma treatment. Predictive models using imaging data may be helpful in prognostic research. [ABSTRACT FROM AUTHOR]

Spinal vertebral hemangiomas (SVHs) are the most common benign tumors of the spine. We performed a systematic review and meta-analysis of radiosurgery (RS) for SVHs. We reviewed articles published between January 1990 and December 2020 on PubMed. Tumor control, pain relief, and damage to surrounding tissues were evaluated with separate meta-analyses. This study was performed in accordance with the published Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A total of 23 patients with 24 SVHs were reported in 3 studies. Follow-up time was 7.3–84 months. The vast majority of lesions were located at dorsal level (n = 18; 75%). In 20 (83.3%) patients, pain was the initial clinical presentation. Complete, partial, and stable responses after radiation were reported in 45.7% (P < 0.001), 23.6% (P = 0.02), and 37.2% (P = 0.7) of cases. Overall response was reported in 94.1% (P = 0.7). No progressive disease was reported. Pain relief was achieved in 87.5% of patients (P = 0.2). Damage to surrounding tissue caused by irradiation was reported in 22.3% (P = 0.02) of cases in 1 study, in which higher doses of radiation were delivered. Radiosurgery is safe and effective for SVHs. Pain relief after RS in symptomatic patients was extremely high, while no progressive disease was reported. Damage to surrounding tissues was reported in only 1 series and included osteitis, osteonecrosis, or soft tissue injury after higher radiation doses. [ABSTRACT FROM AUTHOR]

In the present study, we aimed to identify the obliteration outcomes, complications, and predictors in gamma knife radiosurgery (GKRS) treatment of brain arteriovenous malformations (AVMs) at a tertiary center in a developing country in a 15-year experience. We retrospectively reviewed the clinical data and GKRS procedures of patients who had undergone GKRS from 2006 to 2011 (cohort 1) and from 2011 to 2020 (cohort 2) at Cho Ray Hospital, Vietnam. The exclusion criteria included patients with <24 months of follow-up without obliteration or AVM-related hemorrhage during the study period. A total of 870 patients were included in the final analysis. The patients in cohort 1 had had significantly smaller AVMs (8.4 ± 11.6 cm3 vs. 11.2 ± 12.8 cm3; P < 0.001), and the AVMs were less frequently located in eloquent locations (46.6% vs. 65.5%; P < 0.001) than in cohort 2. The mean follow-up time was 49.6 ± 22.6 months (range, 5.9–102.6). The overall AVM obliteration rate was 66.6%. Cohort 1 had a significantly higher rate of complete obliteration compared with cohort 2 (81.0% vs. 55.1%; P < 0.001). The post-GKRS annual hemorrhage risk was 1.0%. Significant radiosurgery-induced brain edema and radiosurgery-induced cyst formation was reported in 24 (2.6%) and 4 (0.5%) patients in cohorts 1 and 2, respectively. Using multivariate analysis, we identified prior AVM hemorrhage (hazard ratio [HR], 1.430; 95% confidence interval [CI], 1.182–1.729), a higher margin dose (HR, 1.136; 95% CI, 1.086–1.188), a noneloquent location (HR, 0.765; 95% CI, 0.647–0.905), and smaller AVM volume (HR, 0.982; 95% CI, 0.968–0.997) as predictive factors for obliteration. GKRS is a safe and effective treatment of brain AVMs. The lack of prior AVM hemorrhage, an eloquent location, and higher AVM were unfavorable predictors for post-GKRS obliteration. [ABSTRACT FROM AUTHOR]

The fate of residual tumor after salvage surgery for recurrent vestibular schwannoma (VS) after radiosurgery has not been elucidated so far. We reviewed our surgical series of salvage surgery for recurrent VS, with focus on the natural history of the residual tumor after salvage surgery. This study enrolled 14 patients who underwent salvage surgical resection in our institute and were followed up for >12 months. The study included 3 men and 11 women with a median age of 55 years (range: 16–70 years). The median pre–stereotactic radiosurgery tumor volume was 6591 mm3. All patients were treated using gamma knife radiosurgery. The median duration from gamma knife radiosurgery to surgery was 52 months (range: 10–116 months). Solid tumor growth and cyst formation were observed in 6 (42.9%) and 8 (57.1%) patients, respectively. Subtotal resection and partial resection were performed in 13 (92.8%) patients, and gross total resection was achieved in only one (7.2%) patient. Postoperative facial paresis and surgical complication occurred in 5 (35.7%) and 2 (14.3%) patients, respectively. After salvage resection for irradiated VS, no patient showed tumor progression or recurrence during the follow-up period (13 subtotal/partial resections and 1 total resection). In addition, 2 patients in the subtotal resection group showed residual tumor shrinkage after salvage surgery during the follow-up period. The behavior of residual tumors after salvage surgery for irradiated VS was stable. Adjuvant treatment for these residual tumors may not be necessary. [ABSTRACT FROM AUTHOR]

Neurosurgery is a medical field that requires specialized professionals and equipment, 2 important but scarce resources in low- and middle-income countries. Our goal was to report our experience with the replacement and implementation of linear accelerators with radiosurgery capabilities at "Sociedad de Lucha Contra el Cáncer" (SOLCA) Hospital in Quito, Ecuador, and give some recommendations for future technological replacements (TRs). Two surveys were performed in SOLCA's radiosurgery department, one before the TR was finalized and one after, consisting of an open and multiple-choice questionnaire. Questions focused on the performance of the new equipment, perceptions regarding the training, and the influence of the pandemic on the whole process. In addition, we share our experience regarding the difficulties and benefits of TR at SOLCA. The most-reported limitation was lack of training (48%). By the time of the second survey, 95.2% of the staff had already treated patients or planned a radiosurgical procedure; 42.9% considered training to have been adequate, and 76.2% felt that the pandemic hindered the training process. Currently, 33 radiosurgeries have been done (26 for the central nervous system and 7 stereotactic radiation body therapies). The TR in SOLCA had similarities with other experiences in low- and middle-income countries, but the pandemic brought additional limitations, mainly complicating the staff training. Nevertheless, those limitations can be resolved with a structured training program and international collaboration. Overall, the benefits obtained from a TR result in exponentially better medical care and accessibility to novel treatments. [ABSTRACT FROM AUTHOR]

This study investigated the outcomes and prognostic factors of fractionated stereotactic radiosurgery (FSRS) for treatment of brain metastases (BMs) ≥20 mm and determined whether FSRS could replace surgery, the primary treatment for large BMs. Patients with BMs ≥20 mm treated with FSRS were retrospectively examined. Patients who underwent FSRS postoperatively were excluded. Local failure, intracranial failure, and adverse events were evaluated. Overall, 116 lesions in 105 patients were evaluated. The performance status was 0–1, 2–4, and unknown for 86, 28, and 2 patients, respectively. The median maximum tumor diameter was 25 mm, and the median prescribed dose was 35 Gy in 3 fractions. The median follow-up period after FSRS was 8 months. The 1-year local failure, intracranial failure, and overall survival rates were 12.5%, 56.6%, and 49.0%, respectively. A maximum dose of ≥135 Gy (biological equivalent dose [α/β = 10 Gy]) and good performance status were independent favorable prognostic factors for local control. After FSRS, 21 (20%) patients were treated with whole-brain radiotherapy because of multiple intracranial recurrences, and 4 (3.4%) patients underwent surgery because of local recurrence. FSRS for BMs ≥20 mm achieved good local control. Only 3.4% of patients required surgery after FSRS, suggesting that FSRS is a potential alternative to surgery. For FSRS, a higher maximum tumor dose was useful for local control. [ABSTRACT FROM AUTHOR]