Koizumi, Satoshi

BACKGROUND AND OBJECTIVES: Dural arteriovenous fistula (DAVF) is characterized by an abnormal vascular connection located within the dura mater. Stereotactic radiosurgery (SRS) offers favorable outcomes for DAVF, with high obliteration rates and low adverse effects. Although short- to mid-term SRS outcomes for DAVFs and long-term outcomes for arteriovenous malformations have been well documented, the long-term outcomes of SRS for DAVF remain unclear. The aim of this study was to elucidate the late radiation-induced complications (LRICs) of SRS for DAVF based on our long-term observational data. Especially, chronic encapsulated hematoma (CEH), which is defined as an organized intraparenchymal hematoma surrounded by a fibrous capsule, was highlighted as a subtype of LRICs. METHODS: We enrolled 30 consecutive patients with 32 DAVFs who underwent SRS at our institution between 1998 and 2017. Cumulative DAVF obliteration and LRICs rates and associated risk factors were analyzed using the Kaplan-Meier method. Post-SRS signal changes were defined as edematous lesions with high T2 signal intensity that appeared after SRS. RESULTS: The median observation period after the SRS was 99 months. Two asymptomatic CEHs occurred in our cohort and were treated conservatively. The cumulative rates for LRICs after SRS were 5.3% at 8 years and 11.1% at 10 years. Post-SRS signal changes were significantly associated with the occurrence of CEH (25.0% vs 0.0% at 8 years; P = .005; log-rank test). CONCLUSION: Although SRS is effective in treating DAVFs, it poses a risk for LRICs. Post-SRS signal changes may be useful predictors of LRIC occurrence.

BACKGROUND AND OBJECTIVES: Patients with brain arteriovenous malformations (BAVMs) sometimes experience migraine-like chronic headaches. Reportedly, this symptom is common in occipital lobe BAVMs; however, the exact prevalence has not been clarified, and the details of visual auras have been scarcely reported. Furthermore, no comprehensive studies exist on the improvement of migraine associated with visual auras in occipital lobe BAVMs after stereotactic radiosurgery (SRS). Therefore, this study investigated the prevalence of headache with visual aura in patients with occipital lobe BAVMs and evaluated the impact of SRS on preexisting symptoms. METHODS: As a single-center retrospective cohort study, a total of 104 patients with occipital lobe BAVMs treated with SRS from 1990 to 2024 were analyzed. Pre-SRS and post-SRS symptoms of headache and visual aura were documented. The outcomes measured were headache severity, frequency, aura characteristics, and BAVM obliteration rates. RESULTS: Of the 104 patients, 41 (39%) reported chronic headache pre-SRS, and 37 (36%) experienced migraine with visual aura. Compared with pre-SRS, 90% (28/31) of the patients experienced a >50% reduction in headache severity and frequency at a median follow-up of 11 months, and 89% (25/28) experienced a >50% reduction in aura frequency. Complete headache remission was achieved in 35% (13/31) of patients. Complete obliteration of BAVMs was confirmed in 75% (76/102) of the patients at a median of 33 months. A smaller nidus volume was associated with both complete headache remission and BAVM obliteration, whereas age and sex were not significant predictors of headache outcome. CONCLUSION: Patients with occipital lobe BAVMs frequently experience migraine-like headaches with visual aura, which may be more prevalent than in the general population. SRS for occipital lobe BAVMs could not only achieve favorable BAVM obliteration with minimal adverse effects but also significantly improve migraine-like symptoms, including visual aura, particularly in patients with smaller nidus volumes.

OBJECTIVE This study aimed to assess the efficacy and safety of stereotactic radiosurgery (SRS) in treating transverse–sigmoid sinus dural arteriovenous fistulas (TSS DAVFs), and to investigate post-SRS sinus patency, focusing on the risk factors associated with treated sinus occlusion. METHODS Data from 34 patients treated with SRS between January 2006 and April 2023 were analyzed. Detailed angioarchitecture was confirmed using digital subtraction angiography before SRS. Angiography of the ipsilateral internal carotid artery and vertebral artery was performed to evaluate whether the involved side of the TSS was used for normal venous drainage. TSS stenosis was defined as sinus diameter < 50% of the normal proximal diameter. DAVF shunt obliteration, TSS occlusion, neurological status, and adverse events were also evaluated. RESULTS Of the 34 patients, 21 had Borden type I and 14 had Borden type II DAVFs. The median age at SRS was 64 years (interquartile range 54–71 years), and the follow-up period was 31 months (interquartile range 15–94 months). Complete shunt obliteration was achieved in 24 (70.6%) patients. The cumulative 2-, 3-, and 5-year shunt obliteration rates were 49.6%, 71.2%, and 86.0%, respectively. Borden type I had higher obliteration rates (60.5%, 83.1%, and 94.4%, respectively) than Borden type II (41.7%, 51.4%, and 75.7%, respectively; p = 0.034). TSS occlusion occurred in 5 patients (14.7%). The cumulative 1-, 5-, and 10-year TSS occlusion rates were 2.9%, 8.3%, and 23.6%, respectively, across the entire cohort. All occlusions occurred exclusively in the sinuses that were not used for normal venous drainage. Cox proportional analyses revealed that TSS stenosis and the sinus not being used for normal venous drainage were significantly associated with a greater risk of TSS occlusion after SRS (HR 9.44, 95% CI 1.01–77.13; p = 0.049). CONCLUSIONS SRS is effective and safe for TSS DAVF and results in favorable shunt obliteration, symptom improvement, and low complication rates. TSS occlusion after SRS is asymptomatic and is limited to sinuses that are not used for normal venous drainage.

Abstract BACKGROUND High-definition vascular imaging is desirable for treatment planning in Gamma Knife radiosurgery (GKRS; Elekta AB) for brain arteriovenous malformations (BAVMs). Currently, rotational angiography (RA) provides the clearest 3-dimensional visualization of niduses with high spatial resolution; however, its efficacy for GKRS has not been clarified. At our institution, RA has been integrated into GKRS (RA-GKRS) for better treatment planning and outcomes since 2015. OBJECTIVE To evaluate RA-GKRS outcomes of BAVMs and compare them with conventional GKRS (c-GKRS) outcomes. METHODS We retrospectively analyzed the radiosurgical outcomes of 50 BAVMs treated with RA-GKRS compared with the 306 BAVMs treated with c-GKRS. Considering possible differences in the baseline characteristics, we also created propensity score-matched cohorts and compared the radiosurgical outcomes between them to ensure comparability. RESULTS The obliteration time was shorter in the RA-GKRS group (cumulative rate, 88% vs 65% at 4 yr [ P = .001]). Multivariate Cox proportional hazards analysis demonstrated that the RA-GKRS group (hazard ratio 2.38, 95% CI 1.58-3.60; P = .001) had a better obliteration rate. The cumulative 4-yr post-GKRS hemorrhage rates were 4.0% and 2.6% in the RA-GKRS and c-GKRS groups, respectively ( P = .558). There was a trend toward early post-GKRS signal change in the RA-GKRS group compared with the c-GKRS group (cumulative rate, 38% vs 29% at 2 yr; P = .118). Those results were also confirmed in the matched cohort analyses. CONCLUSION The integration of RA into GKRS is promising and may provide earlier nidus obliteration.

OBJECTIVE The major concern about ruptured arteriovenous malformations (rAVMs) is recurrent hemorrhage, which tends to preclude stereotactic radiosurgery (SRS) as a therapeutic modality for these brain malformations. In this study, the authors aimed to clarify the role of SRS for rAVM as a stand-alone modality and an adjunct for a remnant nidus after surgery or embolization. METHODS Data on 410 consecutive patients with rAVMs treated with SRS were analyzed. The patients were classified into groups, according to prior interventions: SRS-alone, surgery and SRS (Surg-SRS), and embolization and SRS (Embol-SRS) groups. The outcomes of the SRS-alone group were analyzed in comparison with those of the other two groups. RESULTS The obliteration rate was higher in the Surg-SRS group than in the SRS-alone group (5-year cumulative rate 97% vs 79%, p < 0.001), whereas no significant difference was observed between the Embol-SRS and SRS-alone groups. Prior resection (HR 1.78, 95% CI 1.30–2.43, p < 0.001), a maximum AVM diameter ≤ 20 mm (HR 1.81, 95% CI 1.43–2.30, p < 0.001), and a prescription dose ≥ 20 Gy (HR 2.04, 95% CI 1.28–3.27, p = 0.003) were associated with a better obliteration rate, as demonstrated by multivariate Cox proportional hazards analyses. In the SRS-alone group, the annual post-SRS hemorrhage rates were 1.5% within 5 years and 0.2% thereafter and the 10-year significant neurological event–free rate was 95%; no intergroup difference was observed in either outcome. The exclusive performance of SRS (SRS alone) was not a risk for post-SRS hemorrhage or for significant neurological events based on multivariate analyses. These results were also confirmed with propensity score–matched analyses. CONCLUSIONS The treatment strategy for rAVMs should be tailored with due consideration of multiple factors associated with the patients. Stand-alone SRS is effective for hemorrhagic AVMs, and the risk of post-SRS hemorrhage was low. SRS can also be favorably used for residual AVMs after initial interventions, especially after failed resection.

Background Although the embolization of lenticulostriate artery feeders is often warranted in the treatment of brain arteriovenous malformations, it is technically challenging due to steep and repeated angulations. Here, we describe our novel technique of navigating a flow-guided microcatheter into lenticulostriate artery feeders using the strong support provided by an S-shaped distal access catheter. Methods We reviewed our retrospective cohort of brain arteriovenous malformations, in which lenticulostriate artery feeders were attempted to embolize. Result During the study period, endovascular embolization was performed in 25 arteriovenous malformations cases. Of these, eight lenticulostriate artery feeders were present in six cases (24%). In two cases, lenticulostriate artery feeder catheterization was avoided from the beginning due to the small diameters of the feeders. After all, microcatheter navigation for lenticulostriate artery feeders were attempted in four cases with six lenticulostriate artery feeders. In all the six feeders, the S-shaped distal access catheter was successful in supporting the microcatheter to advance distally to the lenticulostriate artery feeders, even if other approaches were unsuccessful. Of the six catheterized lenticulostriate artery feeders, four were embolized. Symptomatic infarction in the lenticulostriate artery territory and mild vasospasm occurred in two cases each, but they did not result in permanent neurological deficits. Conclusion Although some potential complications need to be considered, the S-shaped distal access catheter technique appears to be an effective alternative approach to gaining access to difficult feeders of arteriovenous malformations.