Direct Versus Indirect Revascularization for Moyamoya: a Large Multicenter Study.

BACKGROUND: Moyamoya is a chronic occlusive cerebrovascular disease of unknown etiology causing neovascularization of the lenticulostriate collaterals at the base of the brain. Although revascularization surgery is the most effective treatment for moyamoya, there is still no consensus on the best surgical treatment modality as different studies provide different outcomes. OBJECTIVE: In this large case series, we compare the outcomes of direct (DR) and indirect revascularisation (IR) and compare our results to the literature in order to reflect on the best revascularization modality for moyamoya. METHODS: We conducted a multicenter retrospective study in accordance with the Strengthening the Reporting of Observational studies in Epidemiology guidelines of moyamoya affected hemispheres treated with DR and IR surgeries across 13 academic institutions predominantly in North America. All patients who underwent surgical revascularization of their moyamoya-affected hemispheres were included in the study. The primary outcome of the study was the rate of symptomatic strokes. RESULTS: The rates of symptomatic strokes across 515 disease-affected hemispheres were comparable between the two cohorts (11.6% in the DR cohort vs 9.6% in the IR cohort, OR 1.238 (95% CI 0.651 to 2.354), p=0.514). The rate of total perioperative strokes was slightly higher in the DR cohort (6.1% for DR vs 2.0% for IR, OR 3.129 (95% CI 0.991 to 9.875), p=0.052). The rate of total follow-up strokes was slightly higher in the IR cohort (8.1% vs 6.6%, OR 0.799 (95% CI 0.374 to 1.709) p=0.563). CONCLUSION: Since both modalities showed comparable rates of overall total strokes, both modalities of revascularization can be performed depending on the patient's risk assessment.

Nonaneurysmal perimesencephalic subarachnoid hemorrhage on noncontrast head CT: An accuracy, inter-rater, and intra-rater reliability study.

BACKGROUND AND PURPOSE: To evaluate the reliability and accuracy of nonaneurysmal perimesencephalic subarachnoid hemorrhage (NAPSAH) on Noncontrast Head CT (NCCT) between numerous raters. MATERIALS AND METHODS: 45 NCCT of adult patients with SAH who also had a catheter angiography (CA) were independently evaluated by 48 diverse raters; 45 raters performed a second assessment one month later. For each case, raters were asked: 1) whether they judged the bleeding pattern to be perimesencephalic; 2) whether there was blood anterior to brainstem; 3) complete filling of the anterior interhemispheric fissure (AIF); 4) extension to the lateral part of the sylvian fissure (LSF); 5) frank intraventricular hemorrhage; 6) whether in the hypothetical presence of a negative CT angiogram they would still recommend CA. An automatic NAPSAH diagnosis was also generated by combining responses to questions 2-5. Reliability was estimated using Gwet's AC1 (κG), and the relationship between the NCCT diagnosis of NAPSAH and the recommendation to perform CA using Cramer's V test. Multi-rater accuracy of NCCT in predicting negative CA was explored. RESULTS: Inter-rater reliability for the presence of NAPSAH was moderate (κG = 0.58; 95%CI: 0.47, 0.69), but improved to substantial when automatically generated (κG = 0.70; 95%CI: 0.59, 0.81). The most reliable criteria were the absence of AIF filling (κG = 0.79) and extension to LSF (κG = 0.79). Mean intra-rater reliability was substantial (κG = 0.65). NAPSAH weakly correlated with CA decision (V = 0.50). Mean sensitivity and specificity were 58% (95%CI: 44%, 71%) and 83 % (95%CI: 72 %, 94%), respectively. CONCLUSION: NAPSAH remains a diagnosis of exclusion. The NCCT diagnosis was moderately reliable and its impact on clinical decisions modest.

Applied anatomy of the vertebral arteries for endovascular neurointerventions.

The vertebral arteries (VAs) constitute most of the arterial supply to the posterior cerebral vascular circulation. They have anatomical specificities and may have variants that are critical for neurointerventionists to recognize in order to design open or endovascular surgical treatment. This review addresses each segment of the VA including its origin and discusses the branches and relevant anatomical features for neurointerventions.

Craniovertebral and spinal adhesive arachnoiditis: a late complication of ruptured vertebral and posterior inferior cerebellar arteries aneurysms.

BACKGROUND: Adhesive arachnoiditis is a rare yet serious complication that may occur following subarachnoid hemorrhage (SAH). In this circumstance, it is mainly due to ruptured vertebral artery (VA) or posterior inferior artery (PICA) aneurysms. It disrupts cerebrospinal fluid (CSF) flow leading to complications such as spinal arachnoiditis, syringomyelia, trapped 4th ventricle, or a combination of these conditions. Evidence for effective treatment strategies is currently limited. We aimed to review the epidemiology, clinical characteristics, treatment, complications, outcomes, and prognosis of cranio-vertebral junction and spinal adhesive arachnoiditis resulting from ruptured VA and PICA aneurysms. METHODS: This study involved a comprehensive literature review and complemented by our own case. We focused on adult cases of arachnoiditis, syringomyelia, and trapped 4th ventricle with SAH caused by ruptured VA or PICA aneurysms, excluding cases unrelated to these aneurysms and those with insufficient data. RESULTS: The study included 22 patients, with a mean age of 52.4 years. Symptoms commonly manifest within the first year after SAH and timely diagnosis requires a high index of suspicion. Treatment approaches included lysis of adhesions and various shunt procedures. Most patients showed improvement post-treatment, though symptom recurrence is significant. CONCLUSION: Adhesive arachnoiditis is a critical complication following SAH, most commonly from ruptured VA and PICA aneurysms. Early detection and individualized treatment based on the type of arachnoiditis and CSF flow impact are crucial for effective management. This study underscores the need for tailored treatment strategies and further research in this field.

Reliability of study endpoint adjudication in a pragmatic trial on brain arteriovenous malformations.

BACKGROUND: The results of a clinical trial are given in terms of primary and secondary outcomes that are obtained for each patient. Just as an instrument should provide the same result when the same object is measured repeatedly, the agreement of the adjudication of a clinical outcome between various raters is fundamental to interpret study results. The reliability of the adjudication of study endpoints determined by examination of the electronic case report forms of a pragmatic trial has not previously been tested. METHODS: The electronic case report forms of 62/434 (14%) patients selected to be observed in a study on brain AVMs were independently examined twice (4 weeks apart) by 8 raters who judged whether each patient had reached the following study endpoints: (1) new intracranial hemorrhage related to AVM or to treatment; (2) new non-hemorrhagic neurological event; (3) increase in mRS ≥1; (4) serious adverse events (SAE). Inter and intra-rater reliability were assessed using Gwet's AC1 (κG) statistics, and correlations with mRS score using Cramer's V test. RESULTS: There was almost perfect agreement for intracranial hemorrhage (92% agreement; κG = 0.84 (95%CI: 0.76-0.93), and substantial agreement for SAEs (88% agreement; κG = 0.77 (95%CI: 0.67-0.86) and new non-hemorrhagic neurological event (80% agreement; κG = 0.61 (95%CI: 0.50-0.72). Most endpoints correlated (V = 0.21-0.57) with an increase in mRS of ≥1, an endpoint which was itself moderately reliable (76% agreement; κG = 0.54 (95%CI: 0.43-0.64). CONCLUSION: Study endpoints of a pragmatic trial were shown to be reliable. More studies on the reliability of pragmatic trial endpoints are needed.

A review of mechanical thrombectomy techniques for acute ischemic stroke.

Mechanical thrombectomy is established as standard of care in the management of acute ischemic stroke due to large vessel occlusion and evidence-based guidelines for mechanical thrombectomy have been defined. As research continues to further expand the eligibility criteria for thrombectomy and the number of thrombectomy procedures increase worldwide, there is also growing focus on innovation of thrombectomy devices, procedural techniques, and related outcomes. Thrombectomy primarily involves use of stent retrievers and distal aspiration techniques, but variations and different combinations of techniques have been reported. As this is a rapidly evolving area in stroke management, there is debate as to which, if any, of these techniques leads to improved clinical outcomes over another and there is a lack of data comparing them. In this review, currently published and distinct techniques of mechanical thrombectomy are described methodically along with illustrations to aid in understanding the subtle differences between the techniques. The perceived benefits of each variation are discussed.

Onyx Versus Particles for Middle Meningeal Artery Embolization in Chronic Subdural Hematoma.

BACKGROUND: Middle meningeal artery (MMA) embolization has recently emerged as a treatment option for chronic subdural hematoma (cSDH). It is considered a simple and potentially safe endovascular procedure. OBJECTIVE: To compare between 2 different embolic agents; onyx (ethylene vinyl alcohol) and emboparticles (polyvinyl alcohol particles-PVA) for endovascular treatment of cSDH. METHODS: A retrospective analysis of all patients who underwent MMA embolization for cSDH treatment in 2 comprehensive centers between August 2018 and December 2021. Primary outcomes were failure of embolization and need for rescue surgical evacuation. RESULTS: Among 97 MMA embolizations, 49 (50.5%) received onyx and 48 (49.5%) received PVA. The presence of acute or subacute on cSDH was higher in the PVA group 11/49 (22.5%) vs 30/48 (62.5%), respectively, P < .001. There were no significant differences between both groups regarding failure of embolization 6/49 (12.2%) vs 12/48 (25.0%), respectively, P = .112, and need of unplanned rescue surgical evacuation 5/49 (10.2%) vs 8/48 (16.7%), respectively, P = .354. Hematoma thickness at late follow-up was significantly smaller in the PVA group 7.8 mm vs 4.6 mm, respectively; P = .017. CONCLUSION: Both onyx and PVA as embolic agents for cSDH can be used safely and have comparable clinical and surgical outcomes.

Subtemporal Transcollateral Sulcus Approach for Temporal Horn Tumors: 2-Dimensional Operative Video and Description of the Technique.

INTRODUCTION: Purely temporal intraventricular tumors are uncommon. Given their deep location, access to these brain tumors can be challenging in terms of preserving brain tissue. The subtemporal approach spares the lateral temporal cortex and is a less traumatic corridor to reach intraventricular temporal tumors. OBJECTIVE: To describe and assess the feasibility of the subtemporal transcollateral approach for the removal of a temporal horn tumor. METHODS: We describe the subtemporal transcollateral sulcus operative technique detailed step-by-step and depicted through both video and illustrations to surgically resect a left intraventricular temporal mass in a 44-year-old woman who presented with worsening memory deficits. The surgery was performed under general anesthesia and with the use of a microscope and neuronavigation. RESULTS: The patient did not suffer from any postoperative complications. Her vision was intact, and her memory deficit was unchanged. A brain MRI showed complete removal of the tumor. The pathological examination revealed a World Health Organization grade I meningioma. CONCLUSION: The subtemporal transsulcal approach seems to be an efficient and safe way to access intraventricular lesions within the temporal horn while avoiding any disruption of the optic radiations and temporal language areas.

Occipital Artery-Posterior Inferior Cerebellar Artery (PICA) Bypass for the Treatment of a Ruptured Fusiform Aneurysm of the Left PICA: 2-Dimensional Operative Video.

Posterior inferior cerebellar artery (PICA) aneurysms are usually complex to treat because of their deep location, frequent entanglement with the lower cranial nerves, the presence of perforating arteries to the brainstem, and their often dissecting or fusiform morphology.1 These aneurysms can require revascularization of the PICA.2 The length and size of the occipital artery (OA) make it an excellent donor.3,4 Video 1 shows the technical nuances of an OA-PICA bypass for the treatment of a ruptured fusiform aneurysm of the left PICA. The patient is a 34-year-old male presenting with an abrupt headache and confusion (Hunt and Hess grade III and World Federation Neurology Surgeons grade II). Computed tomography of the brain revealed hydrocephalus and subarachnoid hemorrhage (Fisher IV) and digital subtraction angiography revealed a fusiform aneurysm on the tonsillomedullary segment of the left PICA. Given the dissecting nature of this aneurysm and the fact that it was ruptured, we felt it would be safer to be prepared to perform revascularization and to secure the aneurysm using an open surgical approach.5 There were no complications associated with this procedure. The patient remained neurologically intact, and imaging showed good flow through the bypass and no evidence of stroke. OA-PICA bypass is a useful strategy to treat ruptured fusiform PICA aneurysms since it avoids sacrificing the PICA and the use of dual-antiplatelet therapy. This video is one of the few videos published on OA-PICA bypass.6,7 It explains the technical aspects, open and endovascular alternatives, and rationale for this procedure.

Patient and procedure selection for mechanical thrombectomy: Toward personalized medicine and the role of artificial intelligence.

Mechanical thrombectomy (MT) for ischemic stroke due to large vessel occlusion is standard of care. Evidence-based guidelines on eligibility for MT have been outlined and evidence to extend the treatment benefit to more patients, particularly those at the extreme ends of a stroke clinical severity spectrum, is currently awaited. As patient selection continues to be explored, there is growing focus on procedure selection including the tools and techniques of thrombectomy and associated outcomes. Artificial intelligence (AI) has been instrumental in the area of patient selection for MT with a role in diagnosis and delivery of acute stroke care. Machine learning algorithms have been developed to detect cerebral ischemia and early infarct core, presence of large vessel occlusion, and perfusion deficit in acute ischemic stroke. Several available deep learning AI applications provide ready visualization and interpretation of cervical and cerebral arteries. Further enhancement of AI techniques to potentially include automated vessel probe tools in suspected large vessel occlusions is proposed. Value of AI may be extended to assist in procedure selection including both the tools and technique of thrombectomy. Delivering personalized medicine is the wave of the future and tailoring the MT treatment to a stroke patient is in line with this trend.

Scleroderma's Possible Dual Role in the Pathophysiology of Intracranial Aneurysms: Case Report and Literature Review.

BACKGROUND: Scleroderma, or systemic sclerosis, is an autoimmune disorder affecting connective tissues, including blood vessels. Although the exact mechanism is not understood, it results in the production of an abnormal amount of collagen. Cases have been reported in which patients with scleroderma also had intracranial aneurysms. We wish to gain insight into any potential association between the 2 diseases. CASE DESCRIPTION: We reviewed the literature of scleroderma cases with cerebral aneurysms and added our own case, focusing on patient and aneurysm characteristics. Including the present case, this paper pertains to 11 cases with 26 aneurysms. Fifty-five percent had multiple aneurysms, of which two thirds had >2. When data were available, 35% of aneurysms were ≥1 cm, 12% of which were giant. Four aneurysms were fusiform (15%). Patients presented with subarachnoid hemorrhage in 45% of cases. CONCLUSIONS: Scleroderma may lead to the formation of an aneurysm, and the abnormal growth of collagen may protect it from early rupture, allowing it to reach a large size.

Vertebrobasilar Artery Encasement by Skull Base Chordomas: Surgical Outcome and Management Strategies.

BACKGROUND: Vascular encasement by skull base chordomas can increase surgical risk and hinder completeness of resection. However, the evidence behind this remains anecdotic. OBJECTIVE: To give a better portrayal of chordomas encasing vertebrobasilar arteries mainly in regard of surgical vascular risk and its impact on extent of resection. METHODS: A retrospective cohort study comparing skull base chordomas with encasement (≥180o encirclement) of the vertebrobasilar arteries to a control group of skull base chordomas with intradural extension. Data gathered involved pre- and postoperative volumetric analysis of the tumor, degree of encasement of involved vessel, occurrence of complication, and survival data including progression-free survival (PFS) and overall survival (OS). RESULTS: A total of 24 patients with vertebrobasilar encasement were included in the study and an equal number of control cases were randomly selected from the same time period, totalizing 48 patients. Lower clival tumors with condyle involvement were more likely to have encasement. Gross total resection (GTR) rate was significantly lower in the encasement group (13% vs 42%, P = .023). Rates of postoperative new neurological deficit, CFS leak and 30 d postoperative mortality were not statistically different between groups. There was no statistically significant difference in mean PFS (P = .608) and OS (P = .958). CONCLUSION: Skull base chordomas encasing vertebrobasilar arteries are highly challenging tumors. This study demonstrates that although safe resection is possible, GTR is hindered by the presence of encasement. We advocate letting the tumor's adherence to vessels lead the resection, leaving a small piece of tumor behind if adherent to the vessels.

Brain Abscesses After Endovascular Embolization of a Brain Arteriovenous Malformation with Squid.

BACKGROUND: The use of nonadhesive liquid embolic agents (NALEAs) has gained great popularity in the treatment of brain vascular malformations, with a lower rate of local complications than surgery. However, we describe the formation of brain abscesses after endovascular treatment of a brain arteriovenous malformation (bAVM) and how important removal of the NALEAs was in the treatment of these abscesses. CASE DESCRIPTION: A 68-year-old man presented with seizures after being treated for an unruptured bAVM using Squid (Emboflu), an NALEA. Radiologic imaging revealed brain lesions suspicious of abscesses around the previously treated bAVM. A surgical excision of the bAVM and the embolized material was performed as was drainage of the brain abscesses. Bacterial cultures were positive for Enterococcus faecalis, and the patient left the hospital with an appropriate antibiotic regimen without new deficits. CONCLUSIONS: This is the first reported case of a bAVM treated with Squid complicated with brain abscesses, a rare but very serious complication. This complication should be treated not only using antibiotherapy but with complete safe removal of the embolic material.

Amino acid substitutions in σ1 and µ1 outer capsid proteins are selected during mammalian reovirus adaptation to Vero cells.

Establishment of viral persistence in cell culture has previously led to the selection of mammalian reovirus mutants, although very few of those have been characterized in details. In the present study, reovirus was adapted to Vero cells that, in contrast to classically-used L929 cells, are inefficient in supporting the early steps of reovirus uncoating and are also unable to produce interferon as an antiviral response once infection occurs. The Vero cell-adapted reovirus exhibits amino acids substitutions in both the σ1 and µ1 proteins. This contrasts with uncoating mutants from persistently infected L929 cells, and various other cell types, that generally harbor amino acids substitutions in the σ3 outer capsid protein. The Vero cell-adapted virus remained sensitive to an inhibitor of lysosomal proteases; furthermore, in the absence of selective pressure for its maintenance, the virus has partially lost its ability to resist interferon. The positions of the amino acids substitutions on the known protein structures suggest an effect on binding of the viral σ1 protein to the cell surface and on µ1 disassembly from the outer capsid.