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Object: The goal of this study was to evaluate the obliteration rate of intracranial dural arteriovenous fistulas (DAVFs) in patients treated with stereotactic radiosurgery (SRS), and to compare obliteration rates between cavernous sinus (CS) and noncavernous sinus (NCS) DAVFs, and between DAVFs with and without cortical venous drainage (CVD)., Methods: A systematic literature review was performed using PubMed. The CS DAVFs and the NCS DAVFs were categorized using the Barrow and Borden classification systems, respectively. The DAVFs were also categorized by location and by the presence of CVD. Statistical analyses of pooled data were conducted to assess complete obliteration rates in CS and NCS DAVFs, and in DAVFs with and without CVD., Results: Nineteen studies were included, comprising 729 patients harboring 743 DAVFs treated with SRS. The mean obliteration rate was 63% (95% CI 52.4%-73.6%). Complete obliteration for CS and NCS DAVFs was achieved in 73% and 58% of patients, respectively. No significant difference in obliteration rates between CS and NCS DAVFs was found (OR 1.72, 95% CI 0.66-4.46; p=0.27). Complete obliteration in DAVFs with and without CVD was observed in 56% and 75% of patients, respectively. A significantly higher obliteration rate was observed in DAVFs without CVD compared with DAVFs with CVD (OR 2.37, 95% CI 1.07-5.28; p=0.03)., Conclusions: Treatment with SRS offers favorable rates of DAVF obliteration with low complication rates. Patients harboring DAVFs that are refractory or not amenable to endovascular or surgical therapy may be safely and effectively treated using SRS.

Background: This report presents our 15-year experience with Gamma Knife radiosurgery (GKS) for the treatment of 321 patients with dural arteriovenous fistulas (DAVFs) in different locations., Methods: The most common locations of DAVFs were the cavernous sinus (206 cases) and transverse-sigmoid sinus (72 cases), which together accounted for 86.6 % of cases. In all, 54 patients had undergone embolization or surgery prior to radiosurgery, and the other patients underwent GKS as the primary treatment. During GKS, radiation was confined to the involved sinus wall, which was considered the true nidus of the DAVF. Target volume ranged from 0.8 to 52 cm(3). Marginal and maximum doses to the nidus ranged from 14 to 25 Gy and from 25 to 36 Gy, respectively., Results: The mean follow-up time was 28 months (range 2-149 months). In 264 of 321 patients (82 %) available for follow-up study, 173 (66 %) showed complete obliteration of DAVFs with symptomatic resolution, 87 (33 %) had partial obliteration, 2 (0.8 %) had stationary status, 1 (0.4 %) had progression, and 1 (0.4 %) died from a new hemorrhagic episode. Complications were found in only two (0.8 %) patients, one with venous hemorrhage and one with focal brain edema after GKS., Conclusions: GKS is a safe, effective treatment for DAVFs. It provides a minimally invasive therapeutic option for patients who harbor less-aggressive DAVFs but who suffer from intolerable clinical symptoms. For some aggressive DAVFs with extensive venous hypertension or hemorrhage, multimodal treatment with combined embolization or surgery is necessary.

Dural arteriovenous fistulas (DAVFs) are abnormal arteriovenous communications within the dura. The symptoms depend on their location and the pattern of the venous drainage. Patients with cavernous sinus DAVFs often present with ocular manifestations such as exophthalmos, chemosis and diplopia. Patients with transverse or sigmoid sinus DAVFs frequently experience headache and tinnitus on the affected side. DAVFs with anterograde sinus or cortical venous drainage (CVD) have been clinically regarded as benign, whereas DAVFs with retrograde CVD are considered aggressive in behavior. Similar to other cerebral arteriovenous malformations, DAVFs can hemorrhage, with an estimated annual risk of approximately 1.8%. The recommended therapeutic intervention for a DAVF is dependent on the anticipated natural history of the lesion. Management options include surgical resection, embolization and radiosurgery. Radiosurgical treatment has been used for DAVFs in various locations including the anterior cranial fossa, cavernous sinus, transverse/sigmoid sinus, superior sagittal sinus and tentorium. We present an update on 321 DAVF patients treated at the Taipei Veterans General Hospital using Gamma Knife radiosurgery. The prescribed mean margin dose was 17.2 Gy. In our series, 98% of patients had a stable or improved clinical condition after radiosurgery. Stereotactic radiosurgery using the Gamma Knife is a safe and effective alternative for the treatment of DAVFs., (Copyright © 2013 S. Karger AG, Basel.)

Object: The authors retrospectively reviewed the efficacy and safety of Gamma Knife surgery (GKS) in patients with brainstem cavernous malformations (CMs). The CMs had bled repeatedly and placed the patients at high risk with respect to surgical intervention., Methods: Between 1993 and 2010, 49 patients with symptomatic CMs were treated by GKS. The mean age in these patients was 37.8 years, and the predominant sex was female (59.2%). All 49 patients experienced at least 2 instances of repeated bleeding before GKS; these hemorrhages caused neurological deficits including cranial nerve deficits, hemiparesis, hemisensory deficits, spasticity, chorea or athetosis, and consciousness disturbance., Results: The mean size of the CMs at the time of GKS was 3.2 cm(3) (range 0.1-14.6 cm(3)). The mean radiation dose directed to the lesion was 11 Gy with an isodose level at 60.0%. The mean clinical and imaging follow-up time was 40.6 months (range 1.0-150.7 months). Forty-five patients participated in regularly scheduled follow-up. Twenty-nine patients (59.2%) were followed up for > 2 years, and 16 (32.7%) were followed up for < 2 years. The pre-GKS annual hemorrhage rate was 31.3% (69 symptomatic hemorrhages during a total of 220.3 patient-years). After GKS, 3 episodes of symptomatic hemorrhage were observed within the first 2 years of follow-up (4.29% [corrected] annual hemorrhage rate), and 3 episodes of symptomatic hemorrhage were observed after the first 2 years of follow-up (3.64% [corrected] annual hemorrhage rate). In this study of 49 patients, symptomatic radiation-induced complications developed in only 2 patients (4.1%; cyst formation in 1 patient and perifocal edema with neurological deficits in the other patient). There were no deaths in this group., Conclusions: Gamma Knife surgery is effective in reducing the rate of recurrent hemorrhage. In the authors' experience, it was possible to control bleeding using a low-dose treatment. In addition, there were few symptomatic radiation-induced complications. As a result, the authors believe that GKS is a good alternative treatment for brainstem CMs.

Object: The purpose of this study was to assess the efficacy and safety of Gamma Knife surgery (GKS) for the treatment of cavernous sinus dural arteriovenous fistulas (CSDAVFs) and other intracranial dural arteriovenous fistulas (ODAVFs)., Methods: Among the 238 GKS procedures performed for intracranial DAVFs in the authors' institute, 227 cases (146 CSDAVFs and 81 OIDAVFs) with clinical follow up formed the database from which the authors determined clinical outcome and the incidence of untoward events. One hundred ninety-five cases (118 CSDAVFs and 77 ODAVFs) with imaging follow up formed the database from which the authors determined the imaging results. Older age, female sex, higher incidence of diabetes, and shorter duration of symptoms were noted more in cases of CSDAVF than in ODAVFs. Most patients had symptomatic improvement after GKS. A symptomatic cure was observed in one patient with CSDAVFs as early as 6 weeks. The cumulative cure rate based on follow-up angiography of CSDAVFs approached 75% at 24 months, which was much better than that of ODAVFs (approximately 50% at 24 months). A neuroimaging-based cure lagged behind that of the clinical symptoms. Overall, there were only two nonfatal intracerebral hemorrhages during the follow-up period, both occurring less than 1 week after GKS and both being Cognard Type IIa+b with initial aggressive symptoms. Transient deterioration of neurological status without hemorrhage was noted in six patients with ODAVFs. Thrombosis of the superior ophthalmic vein occurred in 11 patients with CSDAVFs, in two of whom there were unilateral visual impairments. There were three cranial nerve neuropathies: transient in one CSDAVF and one ODAVF involving the jugular foramen, and another one was a CSDAVF previously treated by conventional radiotherapy., Conclusions: Gamma Knife surgery provides a safe and effective option for treatment of intracranial DAVFs with a low risk of complications. In cases of DAVFs with benign clinical presentation, GKS can serve as a primary treatment. In some cases of aggressive DAVFs in which there is extensive retrograde cortical vein drainage, combined treatment with embolization or surgery is suggested.

Object: The aim of this study was to assess the efficacy and safety of radiosurgery for the treatment of dural arteriovenous fistulas (DAVFs) located in the region of the transverse-sigmoid sinus., Methods: A series of 20 patients with DAVFs located in the transverse-sigmoid sinus, who were treated with gamma knife surgery between June 1995 and June 2000, was evaluated. According to the Cognard classification, the DAVF was Type I in four patients. Type IIa in seven, Type IIb in two, and combined Type IIa+b in seven. Nine patients had previously been treated with surgery and/or embolization, whereas 11 patients underwent radiosurgery alone. Radiosurgery was performed using multiple-isocenter irradiation of the delineated DAVF nidus. The target volume ranged from 1.7 to 40.7 cm3. The margin dose delivered to the nidus ranged from 16.5 to 19 Gy at a 50 to 70% isodose level. Nineteen patients were available for follow-up review, the duration of which ranged from 6 to 58 months (median 19 months). Of the 19 patients, 14 (74%) were cured of their symptoms. At follow up, magnetic resonance imaging and/or angiography demonstrated complete obliteration of the DAVF in 11 patients (58%), subtotal obliteration (95% reduction of the nidus) in three (16%), and partial obliteration in another five (26%). There was no neurological complication related to the treatment. One patient experienced a recurrence of the DAVF 18 months after angiographic confirmation of total obliteration, and underwent a second course of radiosurgery., Conclusions: Stereotactic radiosurgery provides a safe and effective option for the treatment of DAVFs involving the transverse and sigmoid sinuses. For some aggressive DAVFs with extensive retrograde cortical venous drainage, however, a combination of endovascular embolization and surgery may be necessary.