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Sinovenous outflow in lateral sinus dural arteriovenous fistulas after stereotactic radiosurgery: a retrospective longitudinal imaging study

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Yong Sin Hu at Taipei Veterans General Hospital
Yong Sin Hu
Cheng-Chia Lee at Taipei Veterans General Hospital
Cheng-Chia Lee
Chia-An Wu at Taipei Medical University Shuang-Ho Hospital
Chia-An Wu
  • Taipei Medical University Shuang-Ho Hospital
Hsiu-Mei Wu
Hsiu-Mei Wu
Hsiu-Mei Wu
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Abstract and Figures

Purpose: To investigate sinovenous outflow restriction (SOR) in lateral sinus dural arteriovenous fistulas (LSDAVFs) after Gamma Knife radiosurgery (GKRS) and its association with complete obliteration. Methods: We retrospectively (1995-2019) enrolled 39 patients with LSDAVFs who had undergone GKRS alone and evaluated their angiography and magnetic resonance imaging (MRI) before and after GKRS. The LS conduits ipsilateral and contralateral to the DAVFs were scored using a 5-point scoring system, with scores ranging from 0 (total occlusion) to 4 (fully patent). SOR was defined by a conduit score < 2. Demographics, imaging features, and outcomes were compared between patients with and without ipsilateral SOR after GKRS. Logistic regression analysis was performed to estimate the odds ratio (OR) for obliteration with the imaging findings. Results: After a median angiographic follow-up of 28 months for the 39 patients, the ipsilateral LS became more restrictive (median conduit score before and after GKRS: 2 vs. 1, p = .011). Twenty-one patients with ipsilateral SOR after GKRS had a significantly lower obliteration rate (52.4% vs. 94.4%, p = .005) than those without SOR. Follow-up SOR was independently associated with a lower obliteration rate (OR 0.05, p = .017) after adjustment for age, cortical venous reflux, and absent sinus flow void on MRI. Conclusion: This study demonstrates a restrictive change of outflow in LSDAVFs after GKRS and a lower obliteration rate in patients with SOR. Follow-up imaging for SOR may help predict outcomes of these patients.
Illustration of Gamma Knife radiosurgery (GKRS) planning. Anteroposterior A and lateral B views of stereotactic right carotid angiogram show a Cognard type IIa right lateral sinus dural arteriovenous fistula (LSDAVF), which was integrated with magnetic resonance imaging (MRI) for GKRS planning. Two slices of axial unenhanced time-of-flight MR angiograms C, D selected from the Gamma Plan dose-planning program demonstrate a 60% isodose line covering the target volume. The target was delineated along the involved LS wall where the AVF occurred and excluded feeding arteries and drainage veins distal to the LS. In this case, the target volume was 10.1 cm³ and the margin dose was 17.5 Gy
Illustration of Gamma Knife radiosurgery (GKRS) planning. Anteroposterior A and lateral B views of stereotactic right carotid angiogram show a Cognard type IIa right lateral sinus dural arteriovenous fistula (LSDAVF), which was integrated with magnetic resonance imaging (MRI) for GKRS planning. Two slices of axial unenhanced time-of-flight MR angiograms C, D selected from the Gamma Plan dose-planning program demonstrate a 60% isodose line covering the target volume. The target was delineated along the involved LS wall where the AVF occurred and excluded feeding arteries and drainage veins distal to the LS. In this case, the target volume was 10.1 cm³ and the margin dose was 17.5 Gy
… 
System used for scoring patency of lateral sinus (LS) outflow. The score for each LS conduit ipsilateral and contralateral to the dural arteriovenous fistula (DAVF) was determined separately. The highest degree of stenosis encountered from the torcula to the jugular vein was identified, and the corresponding number was assigned from 0 (total occlusion) to 4 (fully patent). Sinovenous outflow restriction (SOR) was defined by a conduit score < 2. Schematics LS conduit and anteroposterior view of right carotid angiograms before A, B and 20 months after Gamma Knife radiosurgery (GKRS) C, D in the illustrated patient of Fig. 1 who experienced obliteration of right LSDAVFs and developed SOR following GKRS. The ipsilateral conduit score changed from 4 to 0 owing to right distal transverse sinus occlusion after GKRS
System used for scoring patency of lateral sinus (LS) outflow. The score for each LS conduit ipsilateral and contralateral to the dural arteriovenous fistula (DAVF) was determined separately. The highest degree of stenosis encountered from the torcula to the jugular vein was identified, and the corresponding number was assigned from 0 (total occlusion) to 4 (fully patent). Sinovenous outflow restriction (SOR) was defined by a conduit score < 2. Schematics LS conduit and anteroposterior view of right carotid angiograms before A, B and 20 months after Gamma Knife radiosurgery (GKRS) C, D in the illustrated patient of Fig. 1 who experienced obliteration of right LSDAVFs and developed SOR following GKRS. The ipsilateral conduit score changed from 4 to 0 owing to right distal transverse sinus occlusion after GKRS
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Imaging features of venous sinus change after Gamma Knife radiosurgery (GKRS) in 2 lateral sinus dural arteriovenous fistulas (LSDAVFs). A right LSDAVF shown on time-of-flight magnetic resonance angiography A developed sinus wall thickening (arrow in C), demonstrated by T2-weighted images taken before B and 18 months after GKRS C. In another left LSDAVF shown on magnetic resonance angiography D, T2-weighted images taken before E and 65 months after GKRS F exhibit disappearance of normal sinus flow void (arrowhead in F)
Imaging features of venous sinus change after Gamma Knife radiosurgery (GKRS) in 2 lateral sinus dural arteriovenous fistulas (LSDAVFs). A right LSDAVF shown on time-of-flight magnetic resonance angiography A developed sinus wall thickening (arrow in C), demonstrated by T2-weighted images taken before B and 18 months after GKRS C. In another left LSDAVF shown on magnetic resonance angiography D, T2-weighted images taken before E and 65 months after GKRS F exhibit disappearance of normal sinus flow void (arrowhead in F)
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Ipsilateral conduit scores before and after Gamma Knife radiosurgery for patients with and without sinovenous outflow restriction (SOR) at follow-up. The dashed line and solid line that appear in boldface are linear regression lines for patients with and without SOR at follow-up, respectively
Ipsilateral conduit scores before and after Gamma Knife radiosurgery for patients with and without sinovenous outflow restriction (SOR) at follow-up. The dashed line and solid line that appear in boldface are linear regression lines for patients with and without SOR at follow-up, respectively
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Actuarial probability of obliteration of lateral sinus dural arteriovenous fistulas within 36 months after Gamma Knife radiosurgery, based on whether sinovenous outflow restriction (SOR) is observed at follow-up. The values below the X-axis represent the number of patients remaining in the analysis
Actuarial probability of obliteration of lateral sinus dural arteriovenous fistulas within 36 months after Gamma Knife radiosurgery, based on whether sinovenous outflow restriction (SOR) is observed at follow-up. The values below the X-axis represent the number of patients remaining in the analysis
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Vol.:(0123456789)
1 3
https://doi.org/10.1007/s00701-022-05310-x
ORIGINAL ARTICLE - VASCULAR NEUROSURGERY - OTHER
Sinovenous outflow inlateral sinus dural arteriovenous fistulas
afterstereotactic radiosurgery: aretrospective longitudinal imaging
study
Yong‑SinHu1,2,3· Cheng‑ChiaLee2,4· Chia‑AnWu2,3,5· Hsiu‑MeiWu2,3· Huai‑CheYang2,4· Wan‑YuoGuo2,3·
Chao‑BaoLuo2,3· Kang‑DuLiu2,4· Wen‑YuhChung2,4,6· Chung‑JungLin2,3
Received: 21 April 2022 / Accepted: 3 July 2022
© The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature 2022
Abstract
Purpose To investigate sinovenous outflow restriction (SOR) in lateral sinus dural arteriovenous fistulas (LSDAVFs) after
Gamma Knife radiosurgery (GKRS) and its association with complete obliteration.
Methods We retrospectively (1995–2019) enrolled 39 patients with LSDAVFs who had undergone GKRS alone and evalu-
ated their angiography and magnetic resonance imaging (MRI) before and after GKRS. The LS conduits ipsilateral and
contralateral to the DAVFs were scored using a 5-point scoring system, with scores ranging from 0 (total occlusion) to 4
(fully patent). SOR was defined by a conduit score < 2. Demographics, imaging features, and outcomes were compared
between patients with and without ipsilateral SOR after GKRS. Logistic regression analysis was performed to estimate the
odds ratio (OR) for obliteration with the imaging findings.
Results After a median angiographic follow-up of 28months for the 39 patients, the ipsilateral LS became more restrictive
(median conduit score before and after GKRS: 2 vs. 1, p = .011). Twenty-one patients with ipsilateral SOR after GKRS had a
significantly lower obliteration rate (52.4% vs. 94.4%, p = .005) than those without SOR. Follow-up SOR was independently
associated with a lower obliteration rate (OR 0.05, p = .017) after adjustment for age, cortical venous reflux, and absent sinus
flow void on MRI.
Conclusion This study demonstrates a restrictive change of outflow in LSDAVFs after GKRS and a lower obliteration rate
in patients with SOR. Follow-up imaging for SOR may help predict outcomes of these patients.
Keywords Dural arteriovenous fistula· Vascular disorders· Lateral sinus· Stereotactic radiosurgery· Angioarchitecture·
Digital subtraction angiography
Abbreviations
SOR
Sinovenous outflow restriction
LSDAVF
Lateral sinus dural arteriovenous fistula
GKRS
Gamma Knife radiosurgery
OR Odds ratio
CVR
Cortical venous reflux
DSA
Quantitative digital subtraction angiography
MRI
Magnetic resonance imaging
PPP Pseudo-phlebitic pattern
ONS
Optic nerve sheath
RIC Radiation-induced change
This article is part of the Topical Collection on Vascular
Neurosurgery
* Chung-Jung Lin
bcjlin@gmail.com
1 Department ofRadiology, Taipei Hospital, Ministry
ofHealth andWelfare, NewTaipei, Taiwan
2 School ofMedicine, National Yang Ming Chiao Tung
University, Taipei, Taiwan
3 Department ofRadiology, Taipei Veterans General Hospital,
No. 201, Shipai Rd., Sec. 2, Beitou District, Taipei112,
Taiwan
4 Department ofNeurosurgery, Neurological Institute, Taipei
Veterans General Hospital, Taipei, Taiwan
5 Department ofRadiology, Shuang Ho Hospital, Taipei
Medical University, Taipei, Taiwan
6 Department ofNeurosurgery, Kaohsiung Veterans General
Hospital, Kaohsiung, Taiwan
/ Published online: 13 July 2022
Acta Neurochirurgica (2022) 164:2409–2418
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
Sinus occlusion after SRS for transverse–sigmoid sinus dural arteriovenous fistulas
Article
  • Aug 2024
  • Neurosurg Focus
Sinus occlusion after SRS for transverse-sigmoid sinus dural arteriovenous fistulas TO THE EDITOR: We were interested to read the study by Umekawa et al. 1 evaluating outcomes of 34 patients with transverse-sigmoid sinus dural arteriovenous fistulas (TSS DAVFs) after stereotactic radiosurgery (SRS) (Umekawa M, Shinya Y, Hasegawa H, et al. Safety evaluation of sinus patency after stereotactic radiosurgery for transverse-sigmoid sinus dural arteriovenous fistulas: implications of treatment options for patients with Bor-den type I fistulas. Neurosurg Focus. 2024;56[3]:E12). In this study, post-SRS complete obliteration was achieved in 24 (70.6%) patients and asymptomatic TSS occlusion occurred in 5 (14.7%). The risk factor for TSS occlusion was stenosed TSS without normal venous drainage before SRS. As the authors of relevant studies, we appreciate the opportunity to contribute to the ongoing discussion on this critical topic. 2-5 Our prior studies focusing on the intricacies of sinove-nous outflow in TSS DAVFs have provided insights into the hemodynamic changes and their implications for the management of these lesions. 2-5 The TSS conduit patency was scored in a semiquantitative manner as follows: 0 (to-tal occlusion); 1 (severe stenosis with < 25% patency); 2 (moderate stenosis with 25%-50% patency); 3 (mild ste-nosis with 50%-75% patency); and 4 (nearly or fully patent with 75%-100% patency). 3 Outflow restriction in the TSS DAVFs, indicated by a conduit score of < 2, was associated with hemorrhagic presentation. 3 TSS DAVFs with a nearly patent outflow were more likely to obtain post-SRS complete obliteration. 4 We also observed a restrictive change of the treated sinus in some TSS DAVFs associated with a lower complete obliteration rate. 5 Furthermore, Umekawa et al. 1 brought forth new data on the risk factor associated with treated sinus occlusion, a finding that enhances our understanding of the postprocedural landscape and guides future therapeutic strategies. Intrigued by their approach, we analyzed SRS outcomes of patients with TSS DAVF in our prior study. 5 Among the 31 patients without TSS occlusion before SRS, the treated TSS had severe stenosis in 11 (35.5%) and was not used for normal venous drainage in 12 (38.7%). After a median follow-up of 70 months, complete obliteration was achieved in 24 (77.4%). TSS occlusion occurred in 7 (22.6%), who had severe stenosis and absence of normal venous drainage in the treated sinus. Patients with severe stenosis or without normal venous drainage before SRS in the treated sinus (n = 15) were more likely to develop TSS occlusion (46.7% vs 0%, p = 0.002) and were less likely to achieve complete obliteration (60% vs 93.8%, p = 0.037) than those without (n = 16). These findings show similar SRS outcomes to Umekawa et al. 1 and the association between sinus patency and post-SRS complete obliteration in TSS DAVFs. 4,5 Borden type I TSS DAVFs with sinus stenosis tend to have sinus occlusion without neurological deficits after SRS. We concluded that SRS is a safe and effective option for patients with TSS DAVF who have a nearly patent sinus as well as functionally sufficient venous collaterals. A multidisciplinary approach is required for the management of TSS DAVFs. We thank the authors for taking a step forward to refine the management of these lesions.
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Radiologic Clues to Cerebral Venous Thrombosis
Article
Full-text available
  • Oct 2019
Cerebral venous thrombosis (CVT) is uncommon, representing approximately 0.5% of all cases of cerebrovascular disease worldwide. Many factors, alone or combined, can cause CVT. Although CVT can occur at any age, it most commonly affects neonates and young adults. CVT is difficult to diagnose clinically because patients can present with a wide spectrum of nonspecific manifestations, the most common of which are headache in 89%-91%, focal deficits in 52%-68%, and seizures in 39%-44% of patients. Consequently, imaging is fundamental to its diagnosis. MRI is the most sensitive and specific technique for diagnosis of CVT. The different MRI sequences, with and without the use of contrast material, have variable strengths. Contrast material-enhanced MR venography has the highest accuracy compared with sequences without contrast enhancement.Online supplemental material is available for this article.©RSNA, 2019.
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Lateral Sinus Dural Arteriovenous Fistulas: Sinovenous Outflow Restriction Outweighs Cortical Venous Reflux as a Parameter Associated with Hemorrhage
Article
Full-text available
  • May 2017
  • RADIOLOGY
Purpose To investigate whether sinovenous outflow restriction (SOR) is more strongly associated with hemorrhage than cortical venous reflux (CVR) in patients with lateral sinus dural arteriovenous fistulas (DAVFs). Materials and Methods An institutional review board approved this retrospective study and waiver of informed consent was obtained. From 1995 to 2016, 163 cases of lateral sinus DAVFs were included and divided into hemorrhagic and nonhemorrhagic groups based on initial presentation. Their angiograms and magnetic resonance images were evaluated, with two evaluators independently grading CVR and SOR. The SOR was scored as the combined conduit score (CCS), ranging from zero (total occlusion) to 8 (fully patent). The CVR and CCS of the hemorrhagic and nonhemorrhagic groups were compared. Logistic regression models were established for both the CVR and CCS to compare their performances in discriminating DAVF hemorrhage. Results Sinovenous outflow was significantly more restrictive (lower median CCS) in the hemorrhagic group than in the nonhemorrhagic group (1 vs 6.5; P < .001). A CCS of less than or equal to 2 best discriminated between the groups with a sensitivity of 90.0% and a specificity of 88.1%. The CCS model had a higher discriminative performance than did the CVR model (area under the curve, 0.933 vs 0.843; P = .018). Conclusion The CCS grading system semiquantifies SOR. SOR may represent a stronger risk factor associated with hemorrhage in patients with lateral sinus DAVFs than does CVR, and thus may offer guidance in therapeutic decision making. (c) RSNA, 2017.
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Embolization strategies for intracranial dural arteriovenous fistulas with an isolated sinus: a single-center experience in 20 patients
Article
  • Jun 2021
Background Intracranial dural arteriovenous fistulas (DAVFs) draining into an isolated sinus segment constitute a specific entity within the spectrum of cranial dural AV shunts, with under-reporting of their optimal treatment. Objective To describe the multimodal treatment approach to isolated sinus DAVFs in a large single-center cohort. Methods Retrospective analysis of adult patients with an isolated sinus DAVF treated at our institution between 2004 and 2020 was performed. Cases were analyzed for demographics, clinical presentation, angiographic findings, treatment techniques, angiographic and clinical outcomes, and complications. Results Of 317 patients with DAVFs, 20 (6.3%) with an isolated sinus DAVF underwent treatment. Transarterial embolization was performed through the middle meningeal artery in 9 of 12 procedures, with a success rate of 66.7%. Transarterial glue embolization proved successful in two of five procedures (40%) and Onyx in six of seven procedures (85.7%). Transvenous embolization (TVE) with navigation via the occlusion into the isolated sinus was successful in seven out of nine procedures (77.8%). All three open TVE and one pure open surgical procedure gained complete closure of the fistula. There were two major complications. Complete occlusion of the fistula was eventually obtained in all cases (100%). Conclusions Isolated sinus DAVFs are always aggressive and require a multimodal approach to guarantee closure of the shunt. Transarterial treatment with Onyx achieves good results. Transvenous treatment appears equally successful, navigating into the occluded segment across the occlusion or via burr hole as backup.
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Magnetic Resonance Imaging as a Single Diagnostic Tool for Verifying Radiosurgery Outcomes of Cavernous Sinus Dural Arteriovenous Fistula
Article
  • Feb 2020
  • EUR J RADIOL
Purpose: MRI and MR angiography (MRA) are noninvasive methods for examining cavernous sinus dural arteriovenous fistulas (CSDAVFs) after radiosurgery. In this study, we investigated the accuracy of unenhanced MRI/3-dimensional time-of-flight (3D TOF) MRA in evaluating CSDAVF obliteration as compared with digital subtraction angiography (DSA). Methods: From 1995 to 2012, 48 cases of CSDAVFs received Gamma Knife surgery (GKS) and had undergone both unenhanced MRI/3D TOF MRA and DSA for posttreatment evaluation. Two blinded observers independently interpreted the results of MRI/MRA. The results of MRI/MRA were compared with those of DSA. The sensitivity (the probability of MRI/MRA showing obliteration when DSA showed complete obliteration), specificity, positive predictive value, and negative predictive value for CSDAVF obliteration were reported. Results: The median interval between the final MRI/MRA and the subsequent DSA was 2 months. Follow-up DSA revealed that 38 of 48 (79.2%) CSDAVFs were completely obliterated. The results of interobserver agreement assessment showed almost perfect agreement between the 2 observers. For unenhanced MRI/3D TOF MRA, the observed sensitivity was 84.2%, specificity was 100%, positive predictive value was 100%, and negative predictive value was 62.5%. Conclusions: Unenhanced MRI/3D TOF MRA alone may be adequate to document the complete obliteration of CSDAVFs after GKS. Time-resolved MRA or DSA can be reserved for a suspected residual CSDAVF after a sufficient latency period after GKS.
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Stereotactic Radiosurgery for Cavernous Sinus Versus Noncavernous Sinus Dural Arteriovenous Fistulas: Outcomes and Outcome Predictors
Article
  • Aug 2019
  • NEUROSURGERY
Background: Dural arteriovenous fistulas (DAVFs) can be categorized based on location. Objective: To compare stereotactic radiosurgery (SRS) outcomes between cavernous sinus (CS) and non-CS DAVFs and to identify respective outcome predictors. Methods: This is a retrospective study of DAVFs treated with SRS between 1988 and 2016 at 10 institutions. Patients' variables, DAVF characters, and SRS parameters were included for analyses. Favorable clinical outcome was defined as angiography-confirmed obliteration without radiological radiation-induced changes (RIC) or post-SRS hemorrhage. Other outcomes were DAVFs obliteration and adverse events (including RIC, symptomatic RIC, and post-SRS hemorrhage). Results: The overall study cohort comprised 131 patients, including 20 patients with CS DAVFs (15%) and 111 patients with non-CS DAVFs (85%). Rates of favorable clinical outcome were comparable between the 2 groups (45% vs 37%, P = .824). Obliteration rate after SRS was higher in the CS DAVFs group, even adjusted for baseline difference (OR = 4.189, P = .044). Predictors of favorable clinical outcome included higher maximum dose (P = .014) for CS DAVFs. Symptomatic improvement was associated with obliteration in non-CS DAVFs (P = .005), but symptoms improved regardless of whether obliteration was confirmed in CS DAVFs. Non-CS DAVFs patients with adverse events after SRS were more likely to be male (P = .020), multiple arterial feeding fistulas (P = .018), and lower maximum dose (P = .041). Conclusion: After SRS, CS DAVFs are more likely to obliterate than non-CS ones. Because these 2 groups have different total predictors for clinical and radiologic outcomes after SRS, they should be considered as different entities.
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Results of 1940 embolizations for dural arteriovenous fistulas: Japanese Registry of Neuroendovascular Therapy (JR-NET3)
Article
  • Jun 2019
Objective: Embolization is the most common treatment for dural arteriovenous fistulas (dAVFs). A retrospective, multicenter observational study was conducted in Japan to clarify the nature, frequency, and risk factors for complications of dAVF embolization. Methods: Patient data were derived from the Japanese Registry of Neuroendovascular Therapy 3 (JR-NET3). A total of 40,169 procedures were registered in JR-NET3, including 2121 procedures (5.28%) in which dAVFs were treated with embolization. After data extraction, the authors analyzed complication details and risk factors in 1940 procedures performed in 1458 patients with cranial dAVFs treated with successful or attempted embolization. Results: Transarterial embolization (TAE) alone was performed in 858 cases (44%), and transvenous embolization (TVE) alone was performed in 910 cases (47%). Both TAE and TVE were performed in one session in 172 cases (9%). Complications occurred in 149 cases (7.7%). Thirty-day morbidity and mortality occurred in 55 cases (2.8%) and 16 cases (0.8%), respectively. Non-sinus-type locations, radical embolization as the strategy, procedure done at a hospital that performed dAVF embolization in fewer than 10 cases during the study period, and emergency procedures were independent risk factors for overall complications. Conclusions: Complication rates of dAVF embolization in Japan were acceptable. For better results, the risk factors identified in this study should be considered in treatment decisions.
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Hemorrhage risk of cerebral dural arteriovenous fistulas following Gamma Knife radiosurgery in a multicenter international consortium
Article
  • Mar 2019
  • J NEUROSURG
OBJECTIVE The authors performed a study to evaluate the hemorrhagic rates of cerebral dural arteriovenous fistulas (dAVFs) and the risk factors of hemorrhage following Gamma Knife radiosurgery (GKRS). METHODS Data from a cohort of patients undergoing GKRS for cerebral dAVFs were compiled from the International Radiosurgery Research Foundation. The annual posttreatment hemorrhage rate was calculated as the number of hemorrhages divided by the patient-years at risk. Risk factors for dAVF hemorrhage prior to GKRS and during the latency period after radiosurgery were evaluated in a multivariate analysis. RESULTS A total of 147 patients with dAVFs were treated with GKRS. Thirty-six patients (24.5%) presented with hemorrhage. dAVFs that had any cortical venous drainage (CVD) (OR = 3.8, p = 0.003) or convexity or torcula location (OR = 3.3, p = 0.017) were more likely to present with hemorrhage in multivariate analysis. Half of the patients had prior treatment (49.7%). Post-GRKS hemorrhage occurred in 4 patients, with an overall annual risk of 0.84% during the latency period. The annual risks of post-GKRS hemorrhage for Borden type 2–3 dAVFs and Borden type 2–3 hemorrhagic dAVFs were 1.45% and 0.93%, respectively. No hemorrhage occurred after radiological confirmation of obliteration. Independent predictors of hemorrhage following GKRS included nonhemorrhagic neural deficit presentation (HR = 21.6, p = 0.027) and increasing number of past endovascular treatments (HR = 1.81, p = 0.036). CONCLUSIONS Patients have similar rates of hemorrhage before and after radiosurgery until obliteration is achieved. dAVFs that have any CVD or are located in the convexity or torcula were more likely to present with hemorrhage. Patients presenting with nonhemorrhagic neural deficits and a history of endovascular treatments had higher risks of post-GKRS hemorrhage.
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Venous outflow restriction as a predictor of cavernous sinus dural arteriovenous fistula obliteration after Gamma Knife surgery
Article
  • Jan 2019
OBJECTIVE Gamma Knife surgery (GKS) obliterates 65%–87% of cavernous sinus dural arteriovenous fistulas (CSDAVFs). However, the hemodynamic effect on GKS outcomes is relatively unknown. The authors thus used the classification scheme developed by Suh et al. to explore this effect. METHODS The authors retrospectively (1993–2016) included 123 patients with CSDAVFs who received GKS alone at the institute and classified them as proliferative type (PT; n = 23), restrictive type (RT; n = 61), or late restrictive type (LRT; n = 39) after analyzing their pre-GKS angiography images. Treatment parameters, the presence of numerous arterial feeders, and venous drainage numbers were compared across the CSDAVF types. Patients’ follow-up MR images were evaluated for the presence of complete obliteration. A Kaplan-Meier analysis was conducted to determine the correlation between CSDAVF types and outcomes. RESULTS The 36-month probability of complete obliteration was 74.3% for all patients, with no significant differences across types (p = 0.56). PT had the largest radiation volume (6.5 cm3, p < 0.001), the most isocenters (5, p = 0.015) and venous drainage routes (3, p < 0.001), and the lowest peripheral dose (16.6 Gy, p = 0.011) and isodose level coverage (64.3%, p = 0.006). CSDAVFs presenting with ocular patterns were less likely to be completely obliterated (hazard ratio 0.531, p = 0.009). After adjustment for age, CSDAVFs with more venous drainage routes were less likely to be completely obliterated (hazard ratio 0.784, p = 0.039). CONCLUSIONS GKS is an equally effective treatment option for all 3 CSDAVF types. Furthermore, the number of venous drainage routes may help in predicting treatment outcomes and making therapeutic decisions.
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Evaluation of stereotactic radiosurgery for cerebral dural arteriovenous fistulas in a multicenter international consortium
Article
  • Jan 2019
OBJECTIVE In this multicenter study, the authors reviewed the results obtained in patients who underwent Gamma Knife radiosurgery (GKRS) for dural arteriovenous fistulas (dAVFs) and determined predictors of outcome.METHODS Data from a cohort of 114 patients who underwent GKRS for cerebral dAVFs were compiled from the International Gamma Knife Research Foundation. Favorable outcome was defined as dAVF obliteration and no posttreatment hemorrhage or permanent symptomatic radiation-induced complications. Patient and dAVF characteristics were assessed to determine predictors of outcome in a multivariate logistic regression analysis; dAVF-free obliteration was calculated in a competing-risk survival analysis; and Youden indices were used to determine optimal radiosurgical dose.RESULTSA mean margin dose of 21.8 Gy was delivered. The mean follow-up duration was 4 years (range 0.5-18 years). The overall obliteration rate was 68.4%. The postradiosurgery actuarial rates of obliteration at 3, 5, 7, and 10 years were 41.3%, 61.1%, 70.1%, and 82.0%, respectively. Post-GRKS hemorrhage occurred in 4 patients (annual risk of 0.9%). Radiation-induced imaging changes occurred in 10.4% of patients; 5.2% were symptomatic, and 3.5% had permanent deficits. Favorable outcome was achieved in 63.2% of patients. Patients with middle fossa and tentorial dAVFs (OR 2.4, p = 0.048) and those receiving a margin dose greater than 23 Gy (OR 2.6, p = 0.030) were less likely to achieve a favorable outcome. Commonly used grading scales (e.g., Borden and Cognard) were not predictive of outcome. Female sex (OR 1.7, p = 0.03), absent venous ectasia (OR 3.4, p < 0.001), and cavernous carotid location (OR 2.1, p = 0.019) were predictors of GKRS-induced dAVF obliteration.CONCLUSIONSGKRS for cerebral dAVFs achieved obliteration and avoided permanent complications in the majority of patients. Those with cavernous carotid location and no venous ectasia were more likely to have fistula obliteration following radiosurgery. Commonly used grading scales were not reliable predictors of outcome following radiosurgery.
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