Impact of post-thrombectomy isolated subarachnoid hemorrhage on neurological outcomes in patients with anterior ischemic stroke - a retrospective single-center observational study.

PURPOSE: We aimed to investigate the impact of post-thrombectomy isolated subarachnoid hemorrhage (i-SAH) and other types of intracranial hemorrhage (o-ICH) on patient's neurological outcomes. METHODS: Stroke data from 2018 to 2022 in a tertiary care center were retrospectively analyzed. Patients with large vessel occlusion from ICA to M2 branch were included. Post-thrombectomy intracranial hemorrhages at 24 h were categorized with Heidelberg Bleeding Classification. Neurological impairment of patients was continuously assessed at admission, at 24 h, 48 h and 72 h, and at discharge. Predictors of i-SAH and o-ICH were assessed. RESULTS: 297 patients were included. i-SAH and o-ICH were found in 12.1% (36/297) and 11.4% (34/297) of patients. Overall, NIHSS of i-SAH patients at discharge were comparable to o-ICH patients (median 22 vs. 21, p = 0.889) and were significantly higher than in non-ICH patients (22 vs. 7, p < 0.001). i-SAH often resulted in abrupt deterioration of patient's neurological symptoms at 24 h after thrombectomy. Compared to non-ICH patients, the occurrence of i-SAH was frequently associated with worse neurological outcome at discharge (median NIHSS increase of 4 vs. decrease of 4, p < 0.001) and higher in-hospital mortality (41.7% vs. 23.8%, p = 0.022). Regardless of successful reperfusion (TICI 2b/3), the beneficial impact of thrombectomy appeared to be outweighed by the adverse effect of i-SAH. Incomplete reperfusion and shorter time from symptom onset to admission were associated with higher probability of i-SAH, whereas longer procedure time and lower baseline ASPECTS were predictive for o-ICH occurrence. CONCLUSION: Post-thrombectomy isolated subarachnoid hemorrhage is a common complication with significant negative impact on neurological outcome.

MRI characterization of in vitro clots at 3T and 7T: A technical note.

In acute ischemic stroke, the composition of the occlusive clot can be associated with the underlying pathophysiology and the response to treatment. For these reasons, it is important to characterize the clot composition from clinical scans. We examine the ability of 3T and 7T MRI to distinguish the composition of in vitro clots, using quantitative T1 and T2*, alternatively R2*, mapping. When comparing the two field strengths, we found a tradeoff between sensitivity for clot composition and confidence in the clot depiction associated with spatial resolution. The loss of sensitivity at 7T can be mitigated by combining the T1 and T2* signals.

Interdisciplinary Management of Vascular Anomalies in the Head and Neck. / Interdisziplinäres Management vaskulärer Anomalien im Kopf-Hals-Bereich.

Vascular anomalies in the head and neck area are usually rare diseases and pose a particular diagnostic and therapeutic challenge. They are divided into vascular tumours and vascular malformations. A distinction is made between benign tumours, such as infantile haemangioma, and rare malignant tumours, such as angiosarcoma. Vascular malformations are categorised as simple malformations, mixed malformations, large vessel anomalies and those associated with other anomalies. Treatment is interdisciplinary and various modalities are available. These include clinical observation, sclerotherapy, embolisation, ablative and coagulating procedures, surgical resection and systemic drug therapy. Treatment is challenging, as vascular anomalies in the head and neck region practically always affect function and aesthetics. A better understanding of the genetic and molecular biological basis of vascular anomalies has recently led to clinical research into targeted drug therapies. This article provides an up-to-date overview of the diagnosis, clinic and treatment of vascular anomalies in the head and neck region.

Radiation dose and fluoroscopy time of aneurysm coiling in patients with unruptured and ruptured intracranial aneurysms as a function of aneurysm size, location, and patient age.

PURPOSE: Endovascular treatment of unruptured intracranial aneurysms (UIAs) requires a risk-benefit analysis and adherence to diagnostic reference levels (DRLs). The national DRL (250 Gy·cm2) is only determined for intracranial aneurysm coiling in general, including ruptured intracranial aneurysms (RIAs). This study aims to investigate the dose in the treatment of UIAs and RIAs separately. METHODS: In a retrospective study design, dose area product (DAP) and fluoroscopy time (FT) were assessed for all patients undergoing intracranial aneurysm coiling between 2010 and 2021. DRL was set as the 75th percentile of the dose distribution. A multivariable linear regression analysis was performed to investigate DAP and FT for the two groups, UIA and RIA adjusted for patient age, aneurysm size, and location. RESULTS: 583 (414 females, mean age 56.5 years, 311 UIAs) are included. In the overall population, DAP (median (IQR)) is 157 Gy·cm2 (108-217) with a median FT of 32.7 min (IQR 24.0-47.0). Local DRL is 183 Gy·cm2 for UIAs and 246 Gy·cm2 for RIAs. After adjustment for the other variables, the UIA and RIA groups have a significant effect on both DAP (p < 0.001; 95% CI - 68.432 - - 38.040) and FT (p < 0.001; 95% CI - 628.279 - - 291.254). In general, both DAP and FT increase significantly with patient age and aneurysm size, whereas the location of the aneurysm did not significantly change neither DAP (p = 0.171; 95% CI - 5.537-31.065) nor FT (p = 0.136; 95% CI - 357.391-48.508). CONCLUSION: Both aneurysm size and patient age were associated with increased DAP, whereas aneurysm location did not significantly change DAP or FT. The increased dose in patients with RIAs is likely equivalent to additional diagnostic cerebral four-vessel angiography performed in this group.

Spatial heterogeneity of occlusive thrombus in acute ischemic stroke: A systematic review.

Following the advent of mechanical thrombectomy, occlusive clots in ischemic stroke have been amply characterized using conventional histopathology. Many studies have investigated the compositional variability of thrombi and the consequences of thrombus composition on treatment response. More recent evidence has emerged about the spatial heterogeneity of the clot or the preferential distribution of its components and compact nature. Here we review this emerging body of evidence, discuss its potential clinical implications, and propose the development of adequate characterization techniques.

Radiation exposure in the endovascular therapy of cranial and spinal dural arteriovenous fistula in the last decade: a retrospective, single-center observational study.

PURPOSE: This study aims to determine local diagnostic reference levels (DRLs) in the endovascular therapy (EVT) of patients with cranial and spinal dural arteriovenous fistula (dAVF). METHODS: In a retrospective study design, DRLs and achievable dose (AD) were assessed for all patients with cranial and spinal dAVF undergoing EVT (I) or diagnostic angiography (II). All procedures were performed at the flat-panel angiography-system Allura Xper (Philips Healthcare). Interventional procedures were differentiated according to the region of fistula and the type of procedure. RESULTS: In total, 264 neurointerventional procedures of 131 patients with dAVF (94 cranial, 37 spinal) were executed between 02/2010 and 12/2020. The following DRLs, AD, and mean values could be determined: for cranial dAVF (I) DRL 507.33 Gy cm2, AD 369.79 Gy cm2, mean 396.51 Gy cm2; (II) DRL 256.65 Gy cm2, AD 214.19 Gy cm2, mean 211.80 Gy cm2; for spinal dAVF (I) DRL 482.72 Gy cm2, AD 275.98 Gy cm2, mean 347.12 Gy cm2; (II) DRL 396.39 Gy cm2, AD 210.57 Gy cm2, mean 299.55 Gy cm2. Dose levels of EVT were significantly higher compared to diagnostic angiographies (p < 0.001). No statistical difference in dose levels regarding the localization of dAVF was found. CONCLUSION: Our results could be used for establishing DRLs in the EVT of cranial and spinal dAVF. Because radiation exposure to comparably complex interventions such as AVM embolization is similar, it may be useful to determine general DRLs for both entities together.

Dural venous sinus stenting as a stand-alone treatment for spontaneous skull base CSF leak secondary to venous pseudotumor cerebri syndrome.

Most spontaneous CSF leaks (SCSFL) are associated with an underlying pseudotumor cerebri syndrome (PTCS). Treatment generally includes surgical leak repair and PTCS correction, as untreated PTCS carries a risk of recurrence. We describe a 72-year-old woman with rhinorrhea, aural fullness, and posterior nasal drip. CT and MRI showed signs of CSF hypovolemia and PTCS, as well as bilateral transverse sinus stenoses. CT and MRI cisternography documented CSF leaks through the right cribriform plate and the posterior aspect of the petrous bone. Opening CSF pressure was 6 cm H2O. Dural venous sinus stenting (DVSS) was performed after failed conservative treatment. Rhinorrhea resolved 3 days after stenting, aural fullness 1 month later. After 6 months, signs of CSF hypovolemia had disappeared on MRI and the stents were patent. After 9 months, the patient had a transient, spontaneously resolving episode of rhinorrhea. She has been symptom-free for the remaining 39 months of follow-up.

Feasibility of intra-arterial chemotherapy for retinoblastoma: experiences in a large single center cohort study.

PURPOSE: In the last 10 years, intra-arterial chemotherapy (IAC) has been increasingly used in the clinical management of retinoblastoma. It is reported to provide tumor control even in advanced stage disease that might have previously required enucleation. In our clinical experience, there are three conditions that may impair the use of IAC: (1) significant collaterals to meningeal arteries, (2) technical failure of ophthalmic artery catheterization, or (3) retina blood supply from collaterals different to the ophthalmic artery. In the current study, we assessed the rate of IACs that could not be carried out in our institution due to these three reasons. METHODS: All patients admitted for IAC in our hospital were retrospectively assessed by chart review. Non-application rate of IAC was assessed and classified according to the three abovementioned criteria. Complication rate of both finalized and interrupted interventions was recorded. RESULTS: Ninety-eight patients (median age 21.4 months, range 5.3 months-10.5 years) were identified. IAC was performed in 69 (70.4%) patients and interrupted in 12 (12.2%) cases because of meningeal collaterals, in 8 (8.2%) because of technical failure to cannulate the ophthalmic artery, and in 9 (9.2%) because of alternative blood supply of the retina. CONCLUSION: The rather defensive approach that is pursued in our center resulted in an overall non-application rate of IAC around 30%. The relatively high probability of conditions that impair the use of IAC needs to be addressed adequately in the patient conversation prior to the procedure. Our rate of 8% of abstention from IAC due to technical limitations might be reduced by the application of more rigorous therapeutic approaches such as balloon occlusion of the distal internal carotid artery. More research is finally needed to determine if IAC can be safely performed in the presence of meningeal collaterals and via branches of the external carotid artery.

Automated ASPECT rating: comparison between the Frontier ASPECT Score software and the Brainomix software.

PURPOSE: Computer-aided diagnosis (CAD) appears promising in early ischemic change detection computed tomography (CT). This study aimed to compare the performance of two new CAD systems (Frontier ASPECTS Prototype and Brainomix) with two experienced readers in selected patients with suspected acute ischemic stroke. METHODS: Retrospectively, non-contrast brain CTs of 150 patients suspected for acute middle cerebral artery ischemia were analyzed with respect to ASPECTS first separately, than in consensus by two senior radiologists, and by use of Frontier and Brainomix. Besides the fully automatic Frontier and Brainomix readings (Frontier_1, Brainomix_1), readings adjusted for the affected brain side (known by CT angiography or clinical presentation, Frontier_2, Brainomix_2) were assessed. Statistical analysis was performed by intraclass correlation and Bland-Altman statistics. RESULTS: The score-based ASPECTS readings of Brainomix_1, Brainomix_2, both radiologists, and the expert consensus reading correlated highly (r = 0.714 to 0.841; always p < 0.001), whereas Frontier_1 and Frontier_2 correlated only lowly or moderately with both radiologists, the expert consensus reading, and Brainomix (r = 0.471 to 0.680; always p < 0.001). Bland-Altman analysis revealed lower mean ASPECT difference and standard deviation of difference for Brainomix_2 (mean difference = -0.2; SD = 1.15) compared to Frontier_2 (mean difference = 1.2; SD = 1.76). Correlation of region-based ASPECTS reading with the expert consensus reading was moderate for Brainomix_2 (r = 0.534), but only low for Frontier_2 (r = 0283; always p < 0.001). CONCLUSION: We found high agreement in ASPECTS rating between both radiologists, expert consensus reading, and Brainomix, but only low to moderate agreement to Frontier.

A novel, non-adhesive, precipitating liquid embolic implant with intrinsic radiopacity: feasibility and safety animal study.

OBJECTIVES: To evaluate a novel, ready-to-use, iodinated polyvinyl alcohol polymer embolic implant. METHODS: Under good laboratory practice conditions, 26 pigs were investigated. A complex arteriovenous malformation (AVM) model was created in 16 animals, and a simple rete model was used in the remaining 10 animals. The novel material was used for embolization in 22 animals, and a commercially available liquid embolic material in 4 animals as a control group. Animals were killed at 2 days, 3 months and 6 months. Feasibility, efficacy and safety were evaluated radiologically, clinically and histologically. RESULTS: Preparation was easy, without risk of catheter clogging or adhesiveness. Embolic delivery was well controlled under subtracted fluoroscopy. Visibility was homogeneous throughout the injection and the material behaved cohesively upon delivery. Best lesion penetration was obtained with the use of proximal microballoon occlusion. Unforeseen over-dilution of the test material by DMSO prefilled in the microballoon hub changed the material properties and caused inadvertent cerebral embolization leading to death in five animals. This phenomenon was avoided by practical measures. The casts produced no beam-hardening artefacts on CT scans. Histology showed excellent biocompatibility. CONCLUSIONS: Embolization with this novel, iodinated, precipitating polymer was feasible and effective. Care should be taken during delivery to avoid over-dilution of the material by prefilled DMSO. The material is promising for embolization of AVMs and hypervascular lesions. KEY POINTS: • The intrinsically opaque precipitating polymer has adequate fluoroscopic visibility • The polymer does not induce shading or beam-hardening artefacts on CT • The novel liquid embolic material does not require lengthy preparation • Lack of implant adherence reduces the risk of entrapment of the delivery catheter.

Associated Aneurysms in Infratentorial Arteriovenous Malformations: Role of Aneurysm Size and Comparison with Supratentorial Lesions.

BACKGROUND: The natural history and treatment of brain arteriovenous malformations (AVMs) is the object of ongoing debates and discussions. To capture the entirety of these complex lesions, associated vascular pathologies, such as associated aneurysms (AAs), have to be implemented in future risk stratification models, as they are believed to represent additional risk factors for intracranial hemorrhage. The present study aims to determine AA characteristics in posterior fossa AVMs and to compare with AAs accompanying supratentorial AVMs, with special focus on aneurysm size. METHODS: Patients with cerebral AVMs, treated in our department between 1990 and 2013, were analyzed retrospectively. Only patients with flow-related AAs of the feeding arteries were evaluated. Thus, patients harboring intranidal, venous or remote aneurysms were excluded. RESULTS: Of 485 patients with cerebral AVM, 76 patients harbored an AVM of the posterior fossa. Among those, 22 individuals exhibited a total of 35 AAs (n = 8 patients with multiple AAs). Most common location of AAs was the posterior inferior cerebellar artery (n = 20, 57%) and mean AA diameter was 7.9 mm (SD 5.5). In the subgroup of patients with a single AA, mean aneurysm size in posterior fossa AVMs was with 7.8 mm (SD 6.0; range 2-25 mm) significantly larger than the mean size of AAs with supratentorial AVMs (4.8 mm, SD 3.0; range 2-20 mm; p = 0.048). Intracranial hemorrhage was found in 18 of 22 patients (82%) with infratentorial AVMs, and of these, 11 patients suffered from aneurysm rupture. In 14 patients bearing a single AA, 8 (57%) had sustained hemorrhage from aneurysm rupture. The mean diameter of AAs was as supposed in the ruptured group with 9.8 mm (SD 6.9; range 4-25 mm) significantly larger than in the unruptured AA group exhibiting a mean of 5.0 mm (SD 3.3; range 2-10 mm; p = 0.038). Patients with posterior fossa AVMs and AAs were significantly older as compared to those patients with supratentorial lesions (57.1, SD 12.6 vs. 45.8 years, SD 15.9 years; p = 0.004), which was also evident in the subgroup of patients with single AAs (55.2, SD 11.7 vs. 45.8 years, SD 14.9 years; p = 0.038). CONCLUSIONS: AAs of posterior fossa AVMs are larger in diameter than aneurysms accompanying supratentorial AVMs. AA size influences risk for hemorrhage, which, together with the high number of hemorrhagic events in posterior fossa AVMs, justifies treating these pathologies. The higher age of patients with AVMs of the posterior fossa might be one reason for larger AAs in this cohort, when compared to patients with supratentorial AVMs and AAs.

Brain herniations into arachnoid granulations: about 68 cases in 38 patients and review of the literature.

INTRODUCTION: Brain herniations (BH) into arachnoid granulations (AG) in dural venous sinuses and calvarium have rarely been reported in the literature. METHODS: MRIs of 38 patients with BH into AG (BHAG) were retrospectively analyzed. Locations of BHAG, gyrus/lobe of the herniated brain, parenchymal abnormalities of the BH, and clinical and radiological conditions with raised intracranial pressure were recorded. RESULTS: Sixty-eight BHAG were found, by order of frequency, in the occipital squama (OS), transverse sinus (TS), lateral lacuna of the superior sagittal sinus (LLSSS), and straight sinus (SS), with cerebellar tissue being the most frequently involved in BHAG (94.5 % of OS, 55 % of TS, 100 % SS BHAG). Multiple BHAG were found in 58 % of the patients (up to five per patient). Parenchymal signal and structural changes (SSCG) were observed in 46 % of BHAG (100 % were cerebellar). Three patients had pseudotumor cerebri (PTCS); one patient had only MRI signs of PTCS. Twenty-one percent of patients had intracranial conditions susceptible of increasing cerebrospinal fluid (CSF) pressure other than PTCS. CONCLUSIONS: BHAG occurred in the OS, TS, LLSSS, and the SS. SSCG of the herniated cerebellum were frequent and possibly result from tethering/strangulation in the AG. No symptoms could be clearly attributed to BHAG, though in three cases of PTCS, TS BHAG could have contributed to sustaining the raised CSF pressure. Various factors are probably involved in the development of BHAG including normal pia-arachnoid bridges between the brain surface and the AG, hydrodynamic constrains on the brain and AG, and, in some cases, increased intracranial pressure.

Multiple cerebral arterio-venous malformations: impact of multiplicity and hemodynamics on treatment strategies.

BACKGROUND: Multiple AVMs are exceptionally rare lesions and only a few larger series have been published, including other vascular pathologies, such as arterio-venous fistulae (AVF) or patients with hereditary syndromes. Our study presents clinical, angiographic, and therapeutic characteristics of patients harboring sporadic multiple AVMs. METHODS: Basic demographic data, vascular architecture, clinical presentation, treatment strategies, and treatment outcome were analyzed retrospectively from patients with cerebral AVMs treated in our department between 1990 and 2015. RESULTS: Six out of 539 patients (1.1 %) harbored 15 multiple and distinct cerebral lesions. Nidus size was predominantly small, consequently determining a Spetzler-Martin grade °I-°II (three-tier grading system). In three patients, AVMs shared a proximal feeding artery supply, whereas each AVM displayed its own venous drainage. Five of six patients (83 %) presented with hemorrhage. Four patients received therapy of the AVMs with complete elimination in 3/4 patients (75 %) and 8/9 treated AVMs (89 %). All patients with treatment of the AVM showed good-to-excellent recovery (n = 4, mRS ≤ 2). CONCLUSIONS: Multiple cerebral AVMs are complex vascular lesions. The multiplicity of hemodynamic and malformation-related variables influence treatment strategy and sequence. Thus, awareness of these parameters (of various malformations before and during treatment) is important. The high number of hemorrhagic events in the present series might justify a more aggressive treatment of multiple AVMs than previously thought.

Associated aneurysms in supratentorial arteriovenous malformations: impact of aneurysm size on haemorrhage.

BACKGROUND: Associated aneurysms (AAs) are presumed to represent an additional risk factor for intracranial haemorrhage from cerebral arterio-venous malformations (AVMs). To date, efforts to capture their natural history, as well as to identify aneurysms with the potential capability of regression after AVM treatment remain incomprehensive. As the aneurysm size represents an important aspect for the treatment indication of incidental saccular aneurysms, this factor has rarely been encountered for the treatment of AAs so far. The present study aims to determine the angiographic and clinical characteristics of AAs with special focus on aneurysm size and their consequences for treatment. METHODS: Patients with cerebral AVMs, treated in our department between 1990 and 2013, were analyzed retrospectively. Only patients with supratentorial AVMs and flow-related AAs of the feeding arteries were evaluated. Thus, patients harboring AVMs of the cerebellum and the brain stem and patients with intranidal, venous or remote aneurysms were excluded. Treatment strategies were assessed with special attention on bleeding source and on AA size. RESULTS: In 59 of 409 patients (14%) with supratentorial AVMs, a total of 85 AAs of the feeding arteries were identified. 14 of 59 individuals (24%) presented with multiple AAs. Of 85 AA, 58 aneurysms (68%) were classified as proximal and 27 aneurysms (32%) as distal. The most common location of AAs was the middle cerebral artery (MCA, 39%), followed by the internal carotid artery (ICA, 27%) and the anterior cerebral artery (ACA, 21%). The mean AA size was 4.4 mm ± 3.4 mm. Intracranial haemorrhage was found in 21 of 59 patients (36%) with coexisting AAs. Among these, 10 individuals (17%) suffered from rupture of an AA, accounting for nearly half of all bleedings in this subgroup. Among those patients bearing a single AA, the size of ruptured aneurysms differed significantly from those unruptured (6.6 mm vs. 4.4 mm, p = 0.0046). Nineteen patients (32%) received treatment of 22 AAs, whereas sole AVM treatment was adopted in 26 patients (44%) and conservative management in 14 patients (24%). The main reasons to leave AAs untreated were the small AA size (<5 mm), poor clinical state or treatment denial by the patients. CONCLUSIONS: The aneurysm size of AAs in AVM influences the risk of haemorrhage. Therefore, the treatment of larger (diameter ≥5 mm) AAs should be considered, even if a treatment indication of the associated AVM is not given.

Single center experience with treatment of spinal dural arteriovenous fistulas.

Spinal dural arteriovenous fistulas (SDAVFs) are rare pathologies with a yearly incidence of 5-10 new cases/million, constituting 60-80 % of spinal arteriovenous malformations. Clinical symptoms include progressive paraparesis, paresthesias, bladder, and bowel disturbances. The pathophysiology of SDAVFs is not well elucidated. Microneurosurgery and endovascular techniques are established treatment modalities for permanent fistula occlusion, which are oftentimes accompanied by an amelioration of neurological deficits in the long run. Here, we report our interdisciplinary neurosurgical/neuroradiological management strategy of SDAVFs in 32 patients who were evaluated retrospectively. We focused on clinical presentation, microneurosurgical and interventional technique, early, and late neurological results. Quality of life (QoL) was additionally assessed in 12 patients at last follow-up. We discuss the results against the background of the current literature. Our series and the literature indicate that clinical outcome after treatment of SDAVF is favorable in general. Both neurosurgical and neurointerventional therapies appear to be safe and effective, but short-term neurological deterioration after the intervention constitutes an as-of-yet unsolved problem. Beyond age and preoperative neurological state, presence of comorbidities had a significant influence on neurological outcome in our study sample. Self-assessed physical and mental QoL at long-term follow-up was reduced in quite a number of patients and was associated with a poorer neurological result as well as presence of comorbidities. The patients' perspective in terms of QoL was first investigated in this study, but further research on QoL and psychosocial impairment of SDAVF patients is needed to enable individualized counseling and rehabilitation strategies.

Multidisciplinary consensus on assessment of unruptured intracranial aneurysms: proposal of an international research group.

BACKGROUND AND PURPOSE: To address the increasing need to counsel patients about treatment indications for unruptured intracranial aneurysms (UIA), we endeavored to develop a consensus on assessment of UIAs among a group of specialists from diverse fields involved in research and treatment of UIAs. METHODS: After composition of the research group, a Delphi consensus was initiated to identify and rate all features, which may be relevant to assess UIAs and their treatment by using ranking scales and analysis of inter-rater agreement (IRA) for each factor. IRA was categorized as very high, high, moderate, or low. RESULTS: Ultimately, 39 specialists from 4 specialties agreed (high or very high IRAs) on the following key factors for or against UIA treatment decisions: (1) patient age, life expectancy, and comorbid diseases; (2) previous subarachnoid hemorrhage from a different aneurysm, family history for UIA or subarachnoid hemorrhage, nicotine use; (3) UIA size, location, and lobulation; (4) UIA growth or de novo formation on serial imaging; (5) clinical symptoms (cranial nerve deficit, mass effect, and thromboembolic events from UIAs); and (6) risk factors for UIA treatment (patient age and life expectancy, UIA size, and estimated risk of treatment). However, IRAs for features rated with low relevance were also generally low, which underlined the existing controversy about the natural history of UIAs. CONCLUSIONS: Our results highlight that neurovascular specialists currently consider many features as important when evaluating UIAs but also highlight that the appreciation of natural history of UIAs remains uncertain, even within a group of highly informed individuals.

A new-generation, low-permeability flow diverting device for treatment of saccular aneurysms.

OBJECTIVES: We report a preclinical comparative study of a 96-strand braided flow diverter. METHODS: The 96-strand braided device was compared with the currently commercially available flow diverter with 48 strands. The devices were implanted across the neck of 12 elastase-induced aneurysms in New Zealand White rabbits and followed for 1 and 3 months (n = 6 respectively). Aneurysm occlusion rates, parent artery stenosis and patency of jailed branch occlusions were assessed by angiography, histology and scanning electron microscopy studies. RESULTS: It was feasible to navigate and implant the 96-strand device over the aneurysm orifice in all cases. At follow-up two aneurysms in the 48-strand vs. one in the 96-strand group were not occluded. This aneurysm from the 96-strand group however had a tracheal branch arising from the sac and showed a reverse remodelling of the vascular pouch at 3 months. In the occluded aneurysms, the parent artery was always completely reconstructed and the aneurysm orifice was sealed with neointimal tissue. No in-stent stenosis or jailed branch artery occlusion was observed. CONCLUSIONS: The 96-strand flow diverter proved to be safe, biocompatible and haemodynamically effective, induced stable occlusion of aneurysms and led to reverse remodelling of the parent artery. KEY POINTS: • Flow diversion has been introduced to improve endovascular treatment of cerebral aneurysms • A new low-permeability flow diverter is feasible for parent artery reconstruction. • The Silk 96 flow diverter appears effective at inducing aneurysm healing. • The covered branches remained patent at follow-up.

Posterior fossa arterio-venous malformations: current multimodal treatment strategies and results.

The present study aimed to determine the clinical presentation, the multimodal interdisciplinary treatment strategies and outcome of posterior fossa arterio-venous malformations (AVMs) in our neurovascular centre. Fifty-three patients with a posterior fossa AVM were seen between 1998 and 2012 and analysed retrospectively. Patients were either managed conservatively or treated with endovascular, microsurgical or radiosurgical procedures or in combination. Thirty-nine patients (74 %) presented with intracranial haemorrhage and 14 patients (26 %) with unspecific symptoms. In 22 cases with haemorrhage (56 %), an intracerebellar haematoma was found, whereas 17 patients (44 %) suffered from subarachnoid haemorrhage. AVMs were located in the cerebellum in 44 patients (83 %), in the brainstem in four patients (7.5 %) and the cerebello-pontine angle in another four individuals (7.5 %). Forty-two patients (79 %) were treated either by emboliziation (n = 12, 29 %), surgical resection (n = 16, 38 %), surgical resection with preoperative embolization (n = 12, 29 %) or radiotherapy alone (n = 2, 4 %). A total of eleven patients did not receive any treatment (21 %). Both, morbidity and mortality related to treatment were 12 %, whereas overall morbidity and mortality was 26 and 15 %, respectively. Complete AVM elimination was achieved in 81 % of the treated lesions. A multimodal treatment sequence nowadays represents the gold standard for posterior fossa AVMs. Patients are at high risk for morbidity and mortality, due to the impact of haemorrhage and treatment. Therefore, treatment has to be thoroughly indicated, especially for those patients without bleeding. The initial neurological condition seems to be crucial in terms of clinical outcome.

Outcome for unruptured middle cerebral artery aneurysm treatment: surgical and endovascular approach in a single center.

The rupture of an intracranial aneurysm leads to subarachnoid hemorrhage (SAH). To prevent SAH, unruptured lesions can be treated by either endovascular or microsurgical approach. Due to their complex anatomy, middle cerebral artery (MCA) aneurysms represent a unique subgroup of intracranial aneurysms. Primary objective was to determine radiological and clinical outcomes in patients with middle cerebral artery aneurysms who were interdisciplinary treated by either endovascular or microsurgical approach in a single center. Secondary objective was to determine the impact of the lesions' angiographic characteristics on treatment outcome. Clinical and radiological data of 103 patients interdisciplinary treated for unruptured MCA aneurysms over a 5-year period were analyzed in endovascular (n = 16) and microsurgical (n = 87) cohorts. Overall morbidity (Glasgow Outcome Score <5) after 12-month follow-up was 9 %. There was no significant difference between the two cohorts. Complete or "near complete" aneurysm occlusion was achieved in 97 and 75 % in the microsurgical, respective endovascular cohort. A "complex" aneurysm configuration had a significant impact on complete aneurysm occlusion in both cohorts, however, not on clinical outcome. Treatment of unruptured MCA aneurysms can be performed with a low risk of repair using both approaches. However, the risk for incomplete occlusion was higher for the endovascular approach in this series.