ORCID Profile
0000-0003-4604-8205
Current Organisation
Icahn School of Medicine at Mount Sinai
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Publisher: Massachusetts Medical Society
Date: 14-05-2020
DOI: 10.1056/NEJMC2009787
Publisher: Journal of Neurosurgery Publishing Group (JNSPG)
Date: 04-2017
DOI: 10.3171/2017.1.FOCUS16518
Abstract: Endovascular thrombectomy device improvements in recent years have served a pivotal role in improving the success and safety of the thrombectomy procedure. As the intervention gains widespread use, developers have focused on maximizing the reperfusion rates and reducing procedural complications associated with these devices. This has led to a boom in device development. This review will cover novel and emerging technologies developed for endovascular thrombectomy.
Publisher: Journal of Neurosurgery Publishing Group (JNSPG)
Date: 05-2016
DOI: 10.3171/2016.3.FOCUS15635
Abstract: Current standard practice requires an invasive approach to the recording of electroencephalography (EEG) for epilepsy surgery, deep brain stimulation (DBS), and brain-machine interfaces (BMIs). The development of endovascular techniques offers a minimally invasive route to recording EEG from deep brain structures. This historical perspective aims to describe the technical progress in endovascular EEG by reviewing the first endovascular recordings made using a wire electrode, which was followed by the development of nanowire and catheter recordings and, finally, the most recent progress in stent-electrode recordings. The technical progress in device technology over time and the development of the ability to record chronic intravenous EEG from electrode arrays is described. Future applications for the use of endovascular EEG in the preoperative and operative management of epilepsy surgery are then discussed, followed by the possibility of the technique's future application in minimally invasive operative approaches to DBS and BMI.
Publisher: Elsevier BV
Date: 08-2016
DOI: 10.1016/J.WNEU.2016.05.029
Abstract: Recent decades have seen a rapid expansion of involvement of medical students in biomedical research during medical school training. Research within medical school has been shown to influence medical students with regard to medical knowledge, career development, and residency specialty choice. The objective of this study was to evaluate the impact of neurosurgery medical student research grants on neurosurgery residency choice and provide an insight on the demographics of grant awardees. In this retrospective study, a search of award recipients was performed using data available on the American Association of Neurological Surgeons, Congress of Neurological Surgeons, and Neurosurgery Research and Education Foundation websites. Searched years included the first cycle of American Association of Neurological Surgeons/Neurosurgery Research and Education Foundation (2007) and Council of State Neurosurgical Societies/Congress of Neurological Surgeons (2008-2009) grant awards until the 2015-2016 cycle, which is the latest award cycle to date. The initial search yielded 163 research grants that were awarded to 158 students between the years of 2007 and 2016. Among the 163 grant recipients, 126 (77.3%) were men. Among the 88 recipients who entered postgraduate residency programs, 51% (45 of 88) matched into neurosurgery residency. When considering both neurosurgery and neurology residency programs, the percentage increased to 59.1% (52 of 88). Neurosurgery grants for medical students are highly successful in producing future neurosurgeons with >50% of grant recipients matched into neurosurgery. Women are underrepresented in neurosurgery grants and neurosurgery residency programs. This situation can be improved by providing insight about the field early in medical school, perhaps through increased use of neurosurgery medical student grants.
Publisher: Elsevier BV
Date: 11-2017
DOI: 10.1016/J.JOCN.2017.07.026
Abstract: As neurointerventionalists aim to treat occlusions in the ever more distal vasculature, off-label catheters (OLCs) have been adapted for aspiration thrombectomy. This may not be without its attendant risks. Recently issued, a letter from the FDA cautioned providers against using OLCs as substitutes for FDA-cleared aspiration thrombectomy catheters, especially in the distal vasculature. In light of this, we evaluated the efficacy and safety of OLCs used for aspiration thrombectomy in the distal vasculature at our institution. We retrospectively queried all patients who underwent thrombectomy at our institution between January 1, 2016 and March 1, 2017. Patients were screened for: (1) occlusion location in the distal vasculature (M2 or more distal) and (2) direct thrombus aspiration attempt with an OLC. Demographic, clinical, and procedural data were recorded. Eight patients were included for analysis (Table 1). The median admission NIHSS was 17 (IQR 13-23.3). Occlusion locations included left M2 (6/8), right M2 (1/8), and left M3 (1/8). The OLCs employed included the Stryker Catalyst 6 (5/8), Penumbra Velocity (2/8), and the MicroVention Sofia Plus (1/8). Direct thrombus aspiration was successful in 50% (4/8) of cases, though final TICI 2b-3 was achieved in all patients. There were no instances of symptomatic intracranial hemorrhage. Median NIHSS at discharge was 5 (IQR 0.8, 15). Aspiration thrombectomy with OLCs may be safe and effective in the distal vasculature. In light of the recent FDA warning regarding their use, further evaluation of OLCs in this capacity is warranted.
Publisher: BMJ
Date: 17-06-2016
DOI: 10.1136/NEURINTSURG-2016-012439
Abstract: ADAPT (a direct aspiration first pass technique) has been shown to be fast, cost-effective, and associated with excellent angiographic and clinical outcomes in the treatment of acute ischemic stroke (AIS). To identify any and all preoperative factors that are associated with successful revascularization using aspiration alone. A retrospective review of 76 patients with AIS treated with thrombectomy was carried out. Cohort 1 included cases in which aspiration alone was successful (Thrombolysis in Cerebral Infarction 2b or 3). Cohort 2 included cases in which aspiration was unsuccessful or could not be performed despite an attempt. There was no difference between cohorts in gender, race, medications, National Institute of Health Stroke Scale score, IV tissue plasminogen activator, site or side of the occlusion, dense vessel sign, aortic arch type, severe stenosis, clot length, operator years of experience, and guide/aspiration catheters used. Patients in cohort 1 were on average younger (66.5 vs 74.1 years, p=0.025). There was a trend for more patients in cohort 2 to have atrial fibrillation/arrhythmias (62.5% vs 45.5%, p=0.168) and have a cardiogenic stroke etiology (78.1% vs 56.8%, p=0.086). There was also a trend for more reverse curves (2.3 vs 1.7, p=0.107), larger vessel diameter (3.26 mm vs 2.88 mm, p=0.184), larger vessel-to-catheter ratio (2.09 vs 1.87, p=0.192), and worse clot burden score (5.38 vs 6.68, p=0.104) in cohort 2. Aspiration success was associated with younger age. Our findings suggest that ADAPT can be used for the vast majority of patients but it may be beneficial to use a different method first in the elderly.
Publisher: Elsevier BV
Date: 02-2021
Publisher: Informa UK Limited
Date: 02-2021
DOI: 10.2147/OPTH.S272126
Publisher: American Society of Neuroradiology (ASNR)
Date: 14-01-2021
DOI: 10.3174/AJNR.A6971
Publisher: BMJ
Date: 27-01-2022
DOI: 10.1136/NEURINTSURG-2021-018391
Abstract: Artificial intelligence (AI) software is increasingly applied in stroke diagnostics. However, the actual performance of AI tools for identifying large vessel occlusion (LVO) stroke in real time in a real-world setting has not been fully studied. To determine the accuracy of AI software in a real-world, three-tiered multihospital stroke network. All consecutive head and neck CT angiography (CTA) scans performed during stroke codes and run through an AI software engine (Viz LVO) between May 2019 and October 2020 were prospectively collected. CTA readings by radiologists served as the clinical reference standard test and Viz LVO output served as the index test. Accuracy metrics were calculated. Of a total of 1822 CTAs performed, 190 occlusions were identified 142 of which were internal carotid artery terminus (ICA-T), middle cerebral artery M1, or M2 locations. Accuracy metrics were analyzed for two different groups: ICA-T and M1 ±M2. For the ICA-T/M1 versus the ICA-T/M1/M2 group, sensitivity was 93.8% vs 74.6%, specificity was 91.1% vs 91.1%, negative predictive value was 99.7% vs 97.6%, accuracy was 91.2% vs 89.8%, and area under the curve was 0.95 vs 0.86, respectively. Detection rates for ICA-T, M1, and M2 occlusions were 100%, 93%, and 49%, respectively. As expected, the algorithm offered better detection rates for proximal occlusions than for mid/distal M2 occlusions (58% vs 28%, p=0.03). These accuracy metrics support Viz LVO as a useful adjunct tool in stroke diagnostics. Fast and accurate diagnosis with high negative predictive value mitigates missing potentially salvageable patients.
Publisher: American Society of Neuroradiology (ASNR)
Date: 05-08-2021
DOI: 10.3174/AJNR.A7217
Publisher: BMJ
Date: 22-01-2023
Abstract: Surgical treatment of intracerebral hemorrhage (ICH) is unproven, although meta-analyses suggest that both early conventional surgery with craniotomy and minimally invasive surgery (MIS) may be beneficial. We aimed to demonstrate the safety, feasibility, and promise of efficacy of early MIS for ICH using the Aurora Surgiscope and Evacuator. We performed a prospective, single arm, phase IIa Simon’s two stage design study at two stroke centers (10 patients with supratentorial ICH volumes ≥20 mL and National Institutes of Health Stroke Scale (NIHSS) score of ≥6, and surgery commencing hours after onset). Positive outcome was defined as ≥50% 24 hour ICH volume reduction, with the safety outcome lack of significant ICH reaccumulation. From December 2019 to July 2020, we enrolled 10 patients at two Australian Comprehensive Stroke Centers, median age 70 years (IQR 65–74), NIHSS score 19 (IQR 19–29), ICH volume 59 mL (IQR 25–77), at a median of 227 min (IQR 175–377) post-onset. MIS was commenced at a median time of 531 min (IQR 437–628) post-onset, had a median duration of 98 min (IQR 77–110), with a median immediate postoperative hematoma evacuation of 70% (IQR 67–80%). A positive outcome was achieved in 5/5 first stage patients and in 4/5 second stage patients. One patient developed significant 24 hour ICH reaccumulation otherwise, 24 hour stability was observed (median reduction 71% (IQR 61–80), 5/9 patients mL residual). Three patients died, unrelated to surgery. There were no surgical safety concerns. At 6 months, the median modified Rankin Scale score was 4 (IQR 3–6) with 30% achieving a score of 0–3. In this study, early ICH MIS using the Aurora Surgiscope and Evacuator appeared to be feasible and safe, warranting further exploration. ACTRN12619001748101.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 02-03-2022
Publisher: American Society of Neuroradiology (ASNR)
Date: 27-07-2017
DOI: 10.3174/AJNR.A5309
Location: United States of America
Location: United States of America
Location: United States of America
No related grants have been discovered for Christopher Kellner.