Christopher Paul Kellner

BACKGROUND: The EMBOLISE trial (The Embolization of the Middle Meningeal Artery With Onyx Liquid Embolic System in the Treatment of Subacute and Chronic Subdural Hematoma) demonstrated that middle meningeal artery embolization as an adjunct to surgical drainage reduces recurrence of symptomatic subacute and chronic subdural hematomas. We performed a subgroup analysis of the EMBOLISE surgical cohort to determine how the timing of embolization relative to surgery impacted various outcomes. METHODS: We performed a post hoc subgroup analysis to examine the association of the timing of embolization relative to surgery with the primary end point (hematoma reoperation within 90 days), secondary end points (clinical and radiographic outcomes), and safety end points (serious adverse events, neurological death, all-cause death, and stroke). RESULTS: Middle meningeal artery embolization before surgery (embolization-first group) and middle meningeal artery embolization after surgery (surgery-first group) were performed in 107 and 78 patients, respectively. Demographics and baseline clinical characteristics of the 2 groups were similar. The core laboratory confirmed the procedure to be successful in all patients with similar rates of distal penetration of Onyx into middle meningeal artery branches at the end of the embolization procedure in both groups (49.5% and 48.7%, respectively, P >0.99). Six of 103 patients in the embolization-first group (5.8%) and none in the surgery-first group needed reoperation within 90 days (analysis with observed data, P =0.08). Hematoma volumes at 90 and 180 days were similar except for lower hematoma thickness in the surgery-first group (2.3±3.0 mm versus 4.4±5.6 mm, P =0.03) at 180 days. Clinical and safety outcomes at 30, 90, and 180 days were similar. CONCLUSIONS: Performing surgical drainage before embolization in patients with subacute and chronic subdural hematomas may help minimize treatment failures and enhance hematoma resolution. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT04402632.

Acute ischemic stroke is the greatest cause of morbidity and mortality among cerebrovascular pathologies. Over time, several therapeutic options have been developed for treating patients with stroke, including IV r-tPA (intravenous recombinant tissue-type plasminogen activator) and IV-TNK (intravenous tenecteplase) thrombolysis, and endovascular mechanical thrombectomy, with the latter showing favorable recanalization rates. Stent retrievers and mechanical aspiration, the 2 types of mechanical thrombectomy, are used for acute ischemic stroke due to large-vessel occlusions. The first reported aspiration thrombectomy dates back to 2002, during which a 50 mL syringe was used to generate negative pressure and aspirate a clot. Since then, extensive research and development have transformed aspiration thrombectomy. Penumbra’s first system paved the way for present-day aspiration systems in neurointerventional surgery, such as the Penumbra engine and Thunderbolt aspiration systems. Ongoing innovations have focused on improving access to challenging vascular locations and enabling the removal of large thrombi. Over time, aspiration techniques have also evolved. However, despite successful first-pass complete revascularization, a subset of patients continues to experience poor functional outcomes, highlighting the multifactorial nature of stroke recovery. In this review, we outline in detail the historical development of aspiration pump systems in neuroendovascular surgery, describe the different systems and their technical characteristics, highlight the clinical trials evaluating their efficacy, with particular attention to distinctions between devices, and discuss avenues for future growth.

Importance: Middle meningeal artery embolization (MMAE) is a minimally invasive adjunctive treatment for chronic subdural hematoma (cSDH). The TRUFILL n-butyl cyanoacrylate (n-BCA) liquid embolic system is indicated for embolization of cerebral arteriovenous malformations for presurgical devascularization and may be appropriate for MMAE in patients with cSDH. Objective: To evaluate safety and effectiveness of the study device for MMAE plus standard of care vs standard of care alone in patients with cSDH. Design, Setting, and Participants: The Middle Meningeal Artery Embolization for the Treatment of Subdural Hematomas With TRUFILL n-BCA (MEMBRANE) trial was a prospective, multicenter, open-label, randomized clinical trial conducted from May 27, 2021, to February 6, 2024, at 30 hospitals (28 in the United States and 2 in China). Participants aged 18 to 90 years with symptomatic cSDH and a modified Rankin Scale score of 3 or less were enrolled. Interventions: Site physicians determined whether each patient required surgical or nonsurgical management. Participants in the surgical and nonsurgical cohorts were then randomized 1:1 to receive MMAE plus standard of care or standard of care alone. Main Outcomes and Measures: The primary effectiveness end point was residual or re-accumulation of hematoma (>10 mm; assessed by an independent core laboratory) at 6 months or requiring a surgical procedure on the cSDH within 6 months (conducted as an intention-to-treat analysis). The primary safety end point was incidence of adverse events through 6 months (conducted as an as-treated analysis). Results: A total of 376 participants (188 in MMAE plus standard of care and 188 in standard of care alone) were included. In the MMAE plus standard of care and standard of care alone groups, the mean (SD) age was 70.9 (10.6) and 70.3 (12.1) years, and 45 (23.9%) and 49 (26.1%) were female, respectively. Primary effectiveness end point events occurred in 17 of 146 participants receiving MMAE plus standard of care (11.6%) and 29 of 131 receiving standard of care alone (22.1%) (final estimate of common odds ratio: 0.53 [90% CI, 0.31-0.91]; P = .04), indicating statistically significant benefit for MMAE plus standard of care vs standard of care alone. Adverse events occurred in 130 of 181 participants in the MMAE plus standard of care group (71.8%) and 124 of 190 in the standard of care alone group (65.3%) through 6 months. MMAE plus standard of care treatment was noninferior to standard of care alone based on analysis of good functional outcome at 3 months, as assessed by the modified Rankin Scale. Conclusions and Relevance: In this randomized clinical trial, MMAE plus standard of care significantly reduced rates of recurrence and reoperation vs standard of care alone, without a significant increase in adverse events. Trial registration: ClinicalTrials.gov Identifier, NCT04816591 .

BACKGROUND: Cranioplasty is a common procedure following decompressive craniectomy for traumatic brain injury or stroke, among other reasons, in order to repair a skull defect. Cranioplasty failure is an infrequent occurrence, but in the case of synthetic implants, it is usually caused by infection and incorrect sizing. However, trauma-induced displacement, breakage, and deformities of cranioplasty implants are less common. OBSERVATIONS: The authors present a unique case of a cranioplasty failure due to displacement of a polyetheretherketone (PEEK) implant secondary to catastrophic breakage of the titanium fixation plates. The cause of displacement is unknown but is suspected to be trauma. A subsequent review of the literature contextualizes common reasons for failure among synthetic implants and suggests that fracture of synthetic implants or their fixation plates is extremely rare. LESSONS: The displacement of a PEEK cranioplasty implant due to breakage of titanium fixation plates is a rare, albeit possible, complication of this neurosurgical procedure. Lifestyle modifications are paramount to reduce trauma risk and resultant cranioplasty failure. The addition of miniplates may also reduce implant displacement risk. Finally, since rates of failure differ by material, careful consideration of the type of material used for the implant should be incorporated into neurosurgical planning. https://thejns.org/doi/10.3171/CASE2694

Background The middle meningeal artery (MMA) has emerged as an endovascular route for treating chronic subdural hematoma (CSDH), meningioma, and refractory headaches. The third ARISE roundtable convened experts from neurology, neurosurgery, neuroradiology, industry, and regulatory agencies to develop consensus guidance on current evidence for MMA-based therapies Methods Over 50 experts participated in a multi-stakeholder discussion. Evidence from randomized and observational studies, early-phase interventional series, and preclinical work was reviewed. Breakout groups focused on four domains: (1) MMA embolization (MMAE) for CSDH, (2) preoperative embolization of meningiomas, (3) MMA-targeted therapies for headache, and (4) transvascular access for endovascular drainage of subdural hematomas. Consensus recommendations were developed by a writing committee Results Randomized trials support MMAE as an adjunct to surgery or medical management for selected patients with non-acute, symptomatic CSDH to reduce recurrence, progression, and reoperation. Evidence remains insufficient to support MMAE for acute or asymptomatic subdural hematomas. For meningioma, observational data suggest that preoperative embolization in experienced centers can reduce blood loss and operative time and may delay recurrence in large, hypervascular tumors with predominant dural or external carotid supply; primary embolization and intra-arterial oncologic therapies remain investigational. Early series of MMA-directed lidocaine infusion for refractory migraine, status migrainosus, and post-subarachnoid hemorrhage headache show short-term benefit, highlighting the need for controlled trials. Preclinical and first-in-human studies of combined MMAE and transvascular drainage for CSDH demonstrate high technical success, rapid radiographic and clinical improvement, and no early recurrences Conclusion The MMA represents a vascular pathway for an expanding spectrum of neurointerventional therapies.

Background The impact of intravenous (IV) thrombolysis on the outcomes of aspiration thrombectomy as the primary endovascular approach to stroke in patients with large vessel occlusion is unknown. Methods The Imperative Trial was a prospective, investigational device exemption, multicenter trial of first-line aspiration thrombectomy that assessed the safety and efficacy of the Zoom System, including a novel 0.088 inch aspiration catheter in patients with stroke within 8 hours of onset. We compared procedural, technical, and clinical outcomes of aspiration thrombectomy based on whether patients had received IV thrombolytics prior to the intervention. Results Among the 260 patients treated with front-line aspiration thrombectomy using the Zoom System, 125 (48%) received IV thrombolysis prior to aspiration. Rates of modified Thrombolysis in Cerebral Infarction (mTICI) ≥2b achieved with the Zoom System were higher in the aspiration-only group than in the combined group (92% vs 81%, P=0.016). Rates of mTICI ≥2c and first pass effect were similar. The use of rescue devices to achieve mTICI ≥2b was less frequent in the aspiration-only group than in the combined group (2% vs 10%, P=0.008). The rates of functional independence (modified Rankin Scale (mRS) score 0–2) in the aspiration-only group and the combined group were 50% and 59%, respectively (P=0.16). Univariate (P=0.30) and multivariate (P=0.47) ordinal regression analyses showed no significant correlation of mRS 0–2 with IV thrombolysis. Both groups had similar safety outcomes including rates of symptomatic intracranial hemorrhage and 90-day mortality. Conclusions Aspiration thrombectomy alone may result in higher rates of successful reperfusion and reduce the need for rescue devices compared with the combined approach with IV thrombolysis.

Background: As minimally invasive surgical evacuation of intracerebral hemorrhage (ICH) becomes increasingly adopted, long-term functional recovery remains heterogeneous and poorly explained. Injury to the corticospinal tract (CST) is central to motor recovery and can be quantified using diffusion tensor imaging (DTI). Because perihematomal edema and mechanical compression can confound DTI in ICH, we hypothesized that application of an edema-correction algorithm to postoperative imaging would reveal prognostic associations between CST injury and long-term outcome. Methods: Patients undergoing minimally invasive surgery for ICH between 2017 and 2024 with postoperative diffusion MRI were retrospectively analyzed at a single center. CST injury was quantified using ipsilesional-to-contralesional fractional anisotropy ratios with free-water correction (rFA-wc) and without, derived from an automated tractography pipeline. Outcomes included 90-day modified Rankin Scale (mRS) and the National Institutes of Health Stroke Scale (NIHSS) motor subscores. Associations were assessed using Spearman correlations and multivariable proportional-odds regression. Results: 60 patients were included, 52 with available 90-day NIHSS motor scores. Lower rFA-wc (decreased CST integrity) correlated with worse mRS (P=0.043) and worse NIHSS motor subscore (P=0.014) and independently increased the odds of worse functional outcome at 90 days (OR 1.41, 95% CI 1.02 to 2.02) and motor deficit (OR 1.78, 95% CI 1.21 to 2.78). Uncorrected metrics showed weaker and less consistent associations with outcome. Strongest associations occurred when postoperative MRI was obtained within 1 week, and incorporation of rFA-wc improved outcome prediction beyond the ICH score. Conclusion: Edema-corrected assessment of postoperative CST integrity reveals a clinically meaningful prognostic signal after minimally invasive ICH evacuation.