Gamma Knife Treatment Research Articles

SURG-16. MULTIDISCIPLINARY TREATMENT OF HEMANGIOBLASTOMAS IN CENTRAL NERVOUS SYSTEM AND FUTURE PROSPECTS

Abstract Hemangioblastomas (HB) in central nervous system are originally benign tumors. However, they are extremely vascular and appropriate treatment of the feeders and drainers is important when performing HB resection. Approximately 20% of HB cases are thought to be caused by von Hippel-Lindau (VHL) disease. Patients with VHL disease often develop multiple HBs, and it may be difficult to treat them with excision alone. Recently, belzutifan, a molecular targeted drug indicated for treating HB in VHL disease cases, was approved by FDA. In this presentation, we will provide an overview of the multidisciplinary treatment at our facility. METHOD At our facility, we performed 84 cases of excision surgery from 1996 to 2019, and analyzed the results of these treatments. A high-definition 3D fused image was created before surgery to identify the feeders and drainers. Tumor embolization was performed on the feeder, which was thought to be located deep within the surgical field. In addition, gamma knife treatment was performed as appropriate for HBs that did not undergo extirpation. RESULTS The breakdown of cases was 46 with VHL disease and 38 with non-VHL disease. Postoperatively, KPS improved in 55% of cases, and some complications occurred in 18%. Gamma Knife treatment has been performed on 58 cases so far, and the 10-year tumor control rate is approximately 80%. DISCUSSION/SUMMARY This presentation revealed that multidisciplinary treatment is effective for HBs. In the future it is necessary to consider which HB cases belzutifan is useful for and how it should be combined with other treatments.

Hypofractionated Gamma Knife Radiosurgery in Big Tumors

Objective: This research aimed to determine the most effective dosages and achieve improved outcomes without surgical intervention, discomfort, or blood loss. Its objective was also to regulate the formation of both benign and malignant tumours and reduce tumour size. Patients and Methods: A study involving 50 patients at Dr. Saad Al-Witry Hospital for Neurosciences and Al-Altaj Hospital examined brain tumours using MRI models, CBCT, and a gamma knife device. Patients with large tumours were included, while those receiving single fractions of treatment and pregnant women were excluded. Patients were prepared using Leksell frames, thermoplastic masks, and personalised stereotactic masks. Gamma Knife radiosurgery sessions were administered based on tumour size, location, and patient tolerance. Results: This study analysed the use of hypofractionation gamma knife treatment for six brain tumours: Meningioma, Glioma, Schwannoma, Arteriovenous Malformations (AVM), Pituitary Adenoma, and Metastasis. The mean dose distribution was higher in metastasis, followed by AVM, meningioma, glioma, schwannoma, and pituitary adenoma. The maximum dose was found in metastasis, followed by meningioma, glioma, pituitary adenoma, AVM, and schwannoma. The coverage of the target reached excellent value for metastasis, followed by AVM and pituitary adenoma. The beam on time for the treatment was highest in meningioma. Following six months of treatment, the study found a significant difference in tumour volume before and after six months. The highest reduction was observed in meningioma cases, followed by glioma and vestibular schwannoma. A study involving ten patients showed a significant reduction in tumours after a year of gamma knife treatment, with meningioma cases showing the highest reduction. Conclusion: The study found that metastasis was the most common cancer, followed by meningioma, glioma, schwannoma, AVM, and schwannoma. After six months, meningioma showed the highest reduction, and meningioma showed a better response to hypofractionation, followed by AVM.

Unforeseen outcomes: Unveiling cyst formation post stereotactic radiosurgery in brain arteriovenous malformations cases

IntroductionCyst formation after stereotactic radiosurgery (SRS) for brain arteriovenous malformations (AVMs) is a rare, delayed but important complication. Prompt recognition and appropriate treatment is essential for good outcome. MethodsWe analysed our institute’s Gamma knife treatment records from 2008 to 2023 and analysed AVM treated patients by gamma knife radiosurgery (GKRS). Patients with cyst formation and with adequate follow up were identified. Clinical details, management and prognosis of these patients was studied in detail along with prior literature review. ResultsA total of 921 AVM patients were treated in the above period and 7 patients were identified with cyst formation. The mean nidus volume was 12.98 ml, the mean radio surgical marginal dose was 23.57 Gy and maximal dose 47.21 Gy. The mean interval gap between SRS and cyst detection was 6.45 years. The mean volume of cyst cavity formed was 47.85 ml. Patients presented either with features of raised intracranial pressure (3) or focal neurological deficits (3) or seizures (1). 3 patients had achieved angiographic nidus obliteration at the time of cyst detection. Treatment was mostly on surgical lines with cyst fenestration(2 patients), excision (3 patients) and emergency decompressive craniectomy (1 patient). 1 patient required additional Ommaya insertion. Conservative management was followed for 1 patient. Residual nidus was treated either by concomitant excision or embolization or redo GKRS.Favourable outcome was seen in 6 out of 7 patients (85.71%) post cyst management with symptomatic and radiological improvement whereas 1 patient (14.28%) died due to refractory status epilepticus secondary to malignant cerebral edema. ConclusionCyst formation after GKRS for AVM treatment is an often-neglected complication due to its low incidence and often long latency period. Long term follow up of patients is hence necessary for prompt recognition. Diagnostic DSA should be done in all patients with cysts to look for residual nidus. Asymptomatic ones can be followed up conservatively while surgical treatment is required for symptomatic cases. Ventricular diversion like Ommaya or cystoperitoneal shunt may be necessary in some cases. Treatment outcome is usually favourable provided timely detection is done.

Polish cross-cultural adaptation of the Glasgow Benefit Inventory as an instrument for the post-intervention measurement of change after Gamma Knife treatment

Polish cross-cultural adaptation of the Glasgow Benefit Inventory as an instrument for the post-intervention measurement of change after Gamma Knife treatment

3161: A novel knowledge-based planning pipeline for generating Gamma Knife treatment plans

3161: A novel knowledge-based planning pipeline for generating Gamma Knife treatment plans

Knowledge-based planning for Gamma Knife.

Current methods for Gamma Knife (GK) treatment planning utilizes either manual forward planning, where planners manually place shots in a tumor to achieve a desired dose distribution, or inverse planning, whereby the dose delivered to a tumor is optimized for multiple objectives based on established metrics. For other treatment modalities like IMRT and VMAT, there has been a recent push to develop knowledge-based planning (KBP) pipelines to address the limitations presented by forward and inverse planning. However, no complete KBP pipeline has been created forGK. To develop a novel (KBP) pipeline, using inverse optimization (IO) with 3D dose predictions for GK. Data were obtained for 349 patients from Sunnybrook Health Sciences Centre. A 3D dose prediction model was trained using 322 patients, based on a previously published deep learning methodology, and dose predictions were generated for the remaining 27 out-of-sample patients. A generalized IO model was developed to learn objective function weights from dose predictions. These weights were then used in an inverse planning model to generate deliverable treatment plans. A dose mimicking (DM) model was also implemented for comparison. The quality of the resulting plans was compared to their clinical counterparts using standard GK quality metrics. The performance of the models was also characterized with respect to the dosepredictions. Across all quality metrics, plans generated using the IO pipeline performed at least as well as or better than the respective clinical plans. The average conformity and gradient indices of IO plans was 0.737 0.158 and 3.356 1.030 respectively, compared to 0.713 0.124 and 3.452 1.123 for the clinical plans. IO plans also performed better than DM plans for five of the six quality metrics. Plans generated using IO also have average treatment times comparable to that of clinical plans. With regards to the dose predictions, predictions with higher conformity tend to result in higher quality KBP plans. Plans resulting from an IO KBP pipeline are, on average, of equal or superior quality compared to those obtained through manual planning. The results demonstrate the potential for the use of KBP to generate GK treatment with minimal humanintervention.

Physical dose validation of dynamic treatment for Gamma Knife radiosurgery.

Dynamic treatment in Gamma Knife (GK) radiosurgery systems delivers radiation continuously with couch movement, as opposed to stationary step-and-shoot treatment where radiation is paused when moving between isocenters. Previous studies have shown the potential for dynamic GK treatment to give faster treatment times and improved dose conformity and homogeneity. However, these studies focused only on computational simulations and lack physicalvalidation. This study aims conduct dynamic treatment dosimetric validation with physical experimental measurements. The experiments aim to (1) address assumptions made with computational studies, such as the validity of treating a continuous path as discretised points, (2) investigate uncertainties in translating computed plans to actual treatment, and (3) determine ideal treatment planning parameters, such as interval distance for the path discretization, collimator change limitations, and minimum isocenter treatmenttimes. This study uses a GK ICON treatment delivery machine, and a motion phantom custom-made to attach to the machine's mask adapter and move in 1D superior-inferior motion. Phantom positioning is first verified through comparisons against couch motion and computed doses. For dynamic treatment experiments, the phantom is moved through a program that first reads the desired treatment plan isocenters' position, time, and collimator sizes, then carries out the motion continuously while the treatment machine delivers radiation. Measurements are done with increasing levels of complexity: varying speed, varying collimator sizes, varying both speed and collimator sizes, then extends the same measurements to simulated 2D motion by combining phantom and couch motion. Dose comparisons between phantom motion radiation measurements and either couch motion measurements or dose calculations are analyzed with 2 mm/2% and 1 mm/2% gamma indices, using both local and global gamma indexcalculations. Phantom positional experiments show a high accuracy, with global gamma indices for all dose comparisons 99%. Discretization level to approximate continuous path as discrete points show the good dose matches with dose calculations when using 1 and 2-mm gaps. Complex 1D motion, including varying speed, collimator sizes, or both, as well as 2D motion with the same complexities, all show good dose matches with dose calculations: the scores are 92.0% for the strictest 1 mm/2% local gamma index calculation, 99.8% for 2 mm/2% local gamma index, and 97.0% for all global gamma indices. Five simulated 2D treatments with optimized plans scored highly as well, with all gamma index scores 95.3% when compared to stationary treatment, and scores 97.9% when compared to plan calculateddose. Dynamic treatment computational studies are validated, with dynamic treatment shown to be physically feasible and deliverable with high accuracy. A 2-mm discretization level in treatment planning is proposed as the best option for shorter dose calculation times while maintaining dose accuracy. Our experimental method enables dynamic treatment measurements using the existing clinical workflow, which may be replicated in other centers, and future studies may include 2D or 3D motion experiments, or planning studies to further quantify potential indication-specificbenefits.

Hearing Outcomes from Gamma Knife Treatment for Intracanalicular Vestibular Schwannomas with Good Initial Hearing.

Background: The objective of this study was to describe the long-term hearing outcomes of gamma knife treatment for unilateral progressing vestibular schwannomas (VS) presenting with good initial hearing using audiologic data. Methods: A retrospective review was performed between 2010 and 2020 to select patients with progressing unilateral VS and good hearing (AAO-HNS class A) treated with stereotactic gamma knife surgery (GKS). Their audiograms were analyzed along with treatment metrics and patient data. Results: Hearing outcomes with a median follow-up of 5 years post-treatment showed statistically significant loss of serviceable hearing: 34.1% of patients maintained good hearing (AAO-HNS class A), and 56.1% maintained serviceable hearing (AAO-HNS class A and B). Non-hearing outcomes are favorable with excellent tumor control and low facial nerve morbidity. Conclusions: Hearing declines over time in intracanalicular VS treated with GKS, with a significant loss of serviceable hearing after 5 years. The mean cochlear dose and the presence of cochlear aperture obliteration by the tumor are the main statistically significant factors involved in the hearing outcomes.

An MR Imaging Study of Communicating Hydrocephalus After Gamma Knife Radiosurgery for Vestibular Schwannoma

Patients with vestibular schwannoma (VS) face a 3.7-23.7% risk developing hydrocephalus. Small-sized VS are associated with communicating or non-communicating hydrocephalus. Hydrocephalus in VS patients can persist or worsen post-tumor removal. Gamma knife radiosurgery is effective, especially in younger patients with functional hearing. Although the causal relationship between gamma knife radiosurgery and hydrocephalus isn't firmly established, this case reports a possible association between developing hydrocephalus and Vestibular schwannoma. Elevated CSF protein suggests communicating hydrocephalus due to tumor necrosis. The rarity of hydrocephalus post-gamma knife surgery likely relates to tumor variations rather than procedural nuances. Gamma Knife radiosurgery for vestibular schwannomas can lead to communicative hydrocephalus. MR imaging, including pre- and post-treatment scans, along with MR CSF cine-flow studies, highlights the link between gamma knife involvement and hydrocephalus development. Despite the rarity, this negative outcome underscores the need for careful consideration and investigation of risk factors associated with hydrocephalus post-radiosurgery. A middle aged man with vestibular schwannoma was investigated in this case. Patient was procedure through gamma knife radiosurgery for vestibular schwannoma. Patient was passed through MR scans before the radio surgical procedure and 9 months past surgical procedure. Nine months later, severe ventriculomegaly was observed, revealing central necrosis in the tumor. Lumbar puncture indicated abnormal CSF characteristics without evidence of infection. Despite a failed endoscopic third ventriculostomy, MR imaging cine-flow studies confirmed free CSF flow, emphasizing the complexity of managing hydrocephalus post-gamma knife radiosurgery for vestibular schwannomas. VS typically occurs in older individuals, this case's younger age and optimal tumor size for gamma knife treatment add complexity. Faster-growing and larger tumors are more prone to post-treatment necrosis and hydrocephalus, necessitating careful management. MR cine-flow aids in hydrocephalus differentiation.

Preemptive Analgesic Application of Compound Lidocaine Cream for Stereotactic Head Holder Fixing in Gamma Knife Treatment

Preemptive Analgesic Application of Compound Lidocaine Cream for Stereotactic Head Holder Fixing in Gamma Knife Treatment

Gamma Knife treatment strategies for paediatric AVMs: approaches to refractory cases

Abstract Introduction: While paediatric arteriovenous malformations (AVMs) often require aggressive therapeutic intervention due to their high bleeding incidence, choosing a course of treatment for deep and eloquent areas and asymptomatic cases is difficult. Sequelae are a concern in children, as they survive for longer after treatment. The authors have long recommended and implemented staged Gamma Knife radiosurgery (GKRS) in their treatment guidelines to maximise therapeutic effects. Methods: Fifty-eight paediatric patients with AVM and ≤15 years old who underwent GKRS under general anesthesia from 2002 to 2020 were followed up for an average of 81·5 months. Obliteration dynamics and clinical outcomes were analysed. Results: The mean patient age was 10·5 years. The mean nidus volume was 6·6 cm3, the complete occlusion rate was 69%, the annual post-irradiation bleeding rate was 2·19% and nine (16%) cases had transient radiation-induced changes. One (1·7%) patient had sequela, and three (5·1%) developed encapsulated hematomas and cysts. Additionally, the 3- and 5-year cumulative occlusion rates were 39·0% and 53·3%, respectively. Multivariate analysis showed significantly higher occlusion rates in patients ≤12 years old and with a nidus volume of ≤4 cm3. Conclusions: GKRS is a useful treatment for paediatric AVM; however, its use poses some challenges.

Relationship between imaging parameters and distortion in magnetic resonance images for gamma knife treatment planning.

In magnetic resonance imaging (MRI), it is necessary to reduce image distortion as much as possible because it suppresses the increase in the planning target volume. This study investigated the relationship between imaging parameters and image distortion when using G-frames. The images were obtained using a 1.5-T MRI system with a 09-101 Pro-MRI phantom. Image distortion was measured by changing the RF pulse mode, gradient mode, asymmetric echo, and bandwidth (BW). The image distortion was increased in the high RF mode than in the Normal mode. The image distortion increased in the following order: Whisper≦Normal<Fast in the different gradient modes. The image distortion increased in the following order: Without≦Weak<Strong in the different asymmetric echo modes. The image distortion increased in the following order: 300Hz/pixel>670Hz/pixel≧REF (150Hz/pixel) in the different Bw. The relationship between parameters and image distortion was clarified in this study when G-frames were used for gamma knife therapy. There is had relationship between the parameters causing variation in the gradient magnetic field and image distortion. Therefore, these parameters should be adjusted to minimize distortion.

A brain MRI dataset and baseline evaluations for tumor recurrence prediction after Gamma Knife radiotherapy

Prediction and identification of tumor recurrence are critical for brain cancer treatment design and planning. Stereotactic radiation therapy delivered with Gamma Knife has been developed as one of the common treatment approaches combined with others by delivering radiation that targets accurately on the tumor while not affecting nearby healthy tissues. In this paper, we release a fully publicly available brain cancer MRI dataset and the companion Gamma Knife treatment planning and follow-up data for the purpose of tumor recurrence prediction. The dataset contains original patient MRI images, radiation therapy data, and clinical information. Lesion annotations are provided, and inclusive preprocessing steps have been specified to simplify the usage of this dataset. A baseline framework based on a convolutional neural network is proposed companionably with basic evaluations. The release of this dataset will contribute to the future development of automated brain tumor recurrence prediction algorithms and promote the clinical implementations associated with the computer vision field. The dataset is made publicly available on The Cancer Imaging Archive (TCIA) (https://doi.org/10.7937/xb6d-py67).

Development and validation of a fully automatic tissue delineation model for brain metastasis using a deep neural network.

Stereotactic radiosurgery (SRS) treatment planning requires accurate delineation of brain metastases, a task that can be tedious and time-consuming. Although studies have explored the use of convolutional neural networks (CNNs) in magnetic resonance imaging (MRI) for automatic brain metastases delineation, none of these studies have performed clinical evaluation, raising concerns about clinical applicability. This study aimed to develop an artificial intelligence (AI) tool for the automatic delineation of single brain metastasis that could be integrated into clinical practice. Data from 426 patients with postcontrast T1-weighted MRIs who underwent SRS between March 2007 and August 2019 were retrospectively collected and divided into training, validation, and testing cohorts of 299, 42, and 85 patients, respectively. Two Gamma Knife (GK) surgeons contoured the brain metastases as the ground truth. A novel 2.5D CNN network was developed for single brain metastasis delineation. The mean Dice similarity coefficient (DSC) and average surface distance (ASD) were used to assess the performance of this method. The mean DSC and ASD values were 88.34%±5.00% and 0.35±0.21 mm, respectively, for the contours generated with the AI tool based on the testing set. The DSC measure of the AI tool's performance was dependent on metastatic shape, reinforcement shape, and the existence of peritumoral edema (all P values <0.05). The clinical experts' subjective assessments showed that 415 out of 572 slices (72.6%) in the testing cohort were acceptable for clinical usage without revision. The average time spent editing an AI-generated contour compared with time spent with manual contouring was 74 vs. 196 seconds, respectively (P<0.01). The contours delineated with the AI tool for single brain metastasis were in close agreement with the ground truth. The developed AI tool can effectively reduce contouring time and aid in GK treatment planning of single brain metastasis in clinical practice.

Frameless Linear Accelerator (LINAC) Based Radiosurgery (SRS) vs. Framed Gamma Knife SRS for Idiopathic Trigeminal Neuralgia (TN)

Stereotactic radiosurgery (SRS) is an effective treatment for idiopathic trigeminal neuralgia (TN). Conventional treatment is done through frame-based solution due to small target and high radiation dose. More recently, LINAC based frameless SRS technique has been established as a patient friendly alternative. Herein we compared our single institution experience of LINAC based frameless SRS vs frame-based gamma knife SRS for TN. The hypothesis is LINAC based frameless SRS can provide equivalent dosimetric and clinical outcome as compared frame-based gamma knife treatment. Patients with idiopathic TN who received SRS treatment (LINAC based frameless treatment or Gamma knife framed treatment) at our institution from 2015-2022 were included. A minimum follow up of 1 year was required. Patient data was extracted from electronic medical records and radiation treatment planning system. Pain intensity was evaluated utilizing a modified 0-4 Barrow Neurological Institute (BNI) pain intensity score, and then dichotomized where BNI score 0-2 represented response to treatment and BNI score 3-4 represented no response. Statistical analysis was conducted with a linear regression model accounting for race, gender, prior pain, pain distribution including laterality and branch involvement, medication regimen at time of treatment, previous radiation treatment, and prior procedures. Response was then compared between both modalities overall and within each sub-group with chi-square testing and linear regression. A total of 81 patients were identified, 14 patients were excluded due to lack of adequate follow-up, leaving 67 for analysis. 12 (17.9%) were male and, 55 (82.1%) were female. All patients were managed with medication prior to SRS treatment. 5 (7.5%) had rhizotomy and 13 (19.4) had microvascular decompression, and 8 (11.9%) had previous gamma-knife radiosurgery prior to SRS treatment at our institution. Of the 67 patients, 23 (34.3%) received frame-based gamma knife SRS, 44(65.7%) received frameless LINAC treatment. 58 (86.6%) radiation naïve patients received 90 Gy in 1 fraction, while out of the 9 who had previously had intracranial radiation treatment 7 (10.4%) received 70 Gy and 2 (3%) received 80 Gy all prescribed to 100% isodose line. All patients were treated with 4 mm cone. There was no significant difference in brainstem dose between these two techniques. Between LINAC-based or Gamma Knife modalities rate of pain control (77.3 % vs 82.6 %, respectively, p = 0.61) as well as toxicity in facial numbness (31.8% vs 21.7%, respectively, p = 0.38) showed no statistical difference. There was no statistically significant signal (p > 0.05) detected within the subgroups analyzed. The linear regression model also showed no significant difference. LINAC based frameless SRS provides comparable dosimetry and pain control for TN as compared to frame-based gamma knife treatment. It is a patient friendly solution for patients with TN.

The impact of opioid administration for post gamma knife radiosurgery frame removal: a prospective quality-improvement study.

In our center, five Gamma Knife proceduralists differed in opioid administration practices prior to Leksell frame removal, providing the opportunity to improve the care of patients with brain metastases by studying whether opioid medications improve pain scores and patient satisfaction during Gamma Knife treatment in a prospective, pseudorandomized fashion. We prospectively administered a questionnaire to patients undergoing Gamma Knife Radiosurgery for metastases between November, 2017 and July, 2018. Using multivariable methods, we assessed whether opioid pain medication administration influenced the change in pain scores after frame removal, and whether they influenced patient satisfaction on how often their pain was controlled, and their overall satisfaction. We included 142 patients. Mean age was 65.2 ± 10.8 years and 52.7% were female. Morphine was the most commonly administered medication. Pain increases were greater around frame removal than placement. Opioids were not associated with any difference in the change in pain scores before and after frame removal, or patient satisfaction. Patients with higher pre-removal pain scores had smaller increases in pain scores after removal; they also had worse pain control and overall satisfaction with their treatment. Morphine administration prior to frame removal did not improve pain scores or pain control satisfaction. Absence of efficacy may be related to delayed onset of action, and stronger and faster-acting agents should be explored. Pre-removal pain scores were associated with decreased pain control and overall satisfaction, further identifying earlier and stronger pain treatment as a potential area for improvement.

LMAP-05 BEVACIZUMAB AND GAMMA KNIFE RADIOSURGERY IN THE TREATMENT OF FIRST-RECURRENCE GLIOBLASTOMA

Abstract Glioblastoma is the most common central nervous system malignancy in adults and remains a uniformly fatal disease despite two decades of developments in surgical management, radiation treatment, chemotherapy, and immunotherapy. There is currently no established standard of care for patients with recurrent glioblastoma following failure of initial Stupp protocol management. In this retrospective cohort study, we set out to determine if the use of bevacizumab and/or Gamma Knife radiosurgery in patients with recurrent disease could have an effect on prolonging progression-free survival (PFS) or overall survival (OS). Patients in the combined treatment group demonstrated longer post-recurrence mean PFS (9.1 ± 6.0 months) and OS (13.5 ± 8.6 months) compared to glioblastoma patients previously reported in the literature, and showed improvements in total OS (p=0.021), total PFS (p=0.057), post-recurrence PFS (p=0.034), and post-recurrence OS (p=0.017) compared to patients who received standalone bevacizumab or Gamma Knife treatment. This study demonstrates that the combined use of an antiangiogenic agent with stereotactic radiosurgery can have significant effects on improving patient survival in recurrent glioblastoma.

Endovascular Treatment of Dural Arteriovenous Fistulas in a Medium-Sized Scandinavian Neurovascular Center

Endovascular treatment is the primary treatment modality for dural arteriovenous fistulas (DAVFs). We performed a retrospective analysis of DAVFs treated in our hospital to determine if high-quality endovascular treatment can be provided in a medium-volume vascular center. From 2007 to 2021, 69 DAVF treatments were undertaken in our hospital. Of these DAVFs, 55 were endovascular, 11 were open surgical procedures, and 3 were Gamma Knife treatments. Of the endovascular treatments, 10 (18.2%) were in ruptured DAVFs. The most common location of endovascularly treated DAVFs was at the transverse/sigmoid sinus (32.7%) and at the cavernous sinus (25.5%). Of the endovascularly treated DAVFs, 38.2% were low-grade fistulas (Cognard I/IIa), whereas 61.8% were high-grade fistulas (Cognard ≥IIb). 58.2% of fistulas were treated transarterially. DAVFs located in the cavernous sinus were treated using coils alone, whereas most other DAVFs were treated with liquid embolics alone or in combination with coils. Complete or near-complete cure was achieved in 74.5% of treatments, whereas 18.2% of treatments resulted in downgrading of the fistula. Twelve patients were retreated once (9 endovascularly) and 1 patient was retreated twice. After retreatment, complete or near-complete cure was achieved in 86.4% of patients. 72.7% of treatments were performed without any remnant or retreatment. There were no procedure-related deaths. One patient experienced a complication resulting in permanent neurologic deficits. Seven other complications (12.7%) were recorded, all asymptomatic or causing only temporary symptoms. Based on our findings, we conclude that high-quality treatment of DAVFs can be provided in a medium-volume vascular center.

Management and Outcome of Intracranial Dural Arteriovenous Fistulas That Have Caused a Hemorrhage in the Posterior Fossa : A Clinical Study.

We evaluated the diagnosis, treatment, and long-term results of patients with dural arteriovenous fistula (dAVF), which is a very rare cause of posterior fossa hemorrhage. This study included 15 patients who underwent endovascular, surgical, combined, or Gamma Knife treatments between 2012 and 2020. Demographics and clinical features, angiographic features, treatment modalities, and outcomes were analyzed. The mean age of the patients was 40 ± 17 (range 17-68), and 68% were men (11/15). Seven of the patients (46.6%) were in the age group of 50 years and older. While the mean Glasgow Coma Scale was 11.5 ± 3.9 (range 4-15), 46.3% presented with headache, and 53.7% had stupor/coma. Four (26.6%) patients had only cerebellar hematoma and headache. All dAVFs had cortical venous drainage. In 11 (73.3%) patients, the fistula was located in the tentorium and was the most common localization. Three (20%) patients had transverse and sigmoid sinus localizations, while one (6.7%) patient had dAVF located in the foramen magnum. Eighteen sessions were performed on the patients during endovascular treatment. Sixteen (88.8%) sessions were performed with the transarterial (TA) route, one (5.5%) session with the transvenous (TV) route, and one (5.5%) session with the TA + TV route. Surgery was performed in two (14.2%) patients. One (7.1%) patient passed away. While there were nine (64.2%) patients with a Rankin score between 0 and 2, the total closure rate was 69.2% in the first year of control angiograms. In the differential diagnosis of posterior fossa hemorrhages, the differential diagnosis of dAVFs, which is a very rare entity, should be considered, even in the middle and elderly age groups, in patients presenting with good clinical status and pure hematoma. The treatment of such patients can be done safely and effectively in a multidisciplinary manner with a good understanding of pathological vascular anatomy and appropriate endovascular treatment approaches.

Gamma Knife Thalamotomy for Essential Tremor: A Retrospective Analysis

Gamma knife (GK) thalamotomy has been used as a treatment option for essential tremor (ET). Numerous studies on GK use in ET treatment have reported more varied responses and complication rates. Data from 27 patients with ET who underwent GK thalamotomy were retrospectively analyzed. The Fahn-Tolosa-Marin Clinical Rating Scale for Tremor, handwriting, and spiral drawing were evaluated. Postoperative adverse events and magnetic resonance imaging findings were also evaluated. The mean age at GK thalamotomy was 78.1±4.2years. The mean follow-up period was 32.5±19.4months. The preoperative postural tremor, handwriting, and spiral drawing scores were 3.4±0.6, 3.3±1.0, and 3.2±0.8, respectively, all of which showed significant improvements to 1.5±1.2 (55.9% improvement, P < 0.001), 1.4±1.1 (57.6% improvement, P < 0.001), and 1.6±1.3 (50% improvement, P < 0.001), respectively, at the available final follow-up evaluations. Three patients presented with no improvement in tremor. Six patients presented with adverse effects, including complete hemiparesis, foot weakness, dysarthria, dysphagia, lip numbness, and finger numbness, at the final follow-up period. Two patients presented with serious complications, including complete hemiparesis due to massive widespread edema and chronic encapsulated expanding hematoma. One patient died of aspiration pneumonia following severe dysphagia secondary to chronic encapsulated expanding hematoma. GK thalamotomy is an efficient procedure for treating ET. Careful treatment planning is necessary to reduce complication rates. The prediction of radiation complications will increase the safety and effectiveness of GK treatment.