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537 citation(s) found for "Walker, J C".

Intracranial Stenting: Angioplasty Basic Technique, Indications, and Sizing: 2-Dimensional Operative Video
Dossani, Rimal H., Cappuzzo, Justin M. , Sonig, Ashish , Siddiqui, Adnan H. , Davies, Jason M. , Bain, Mark, Bendock, Bernard, Binning, Mandy J., Boulos, Alan S. , Crowley, Webster, Fessler, Richard D., Guterman, Lee R., Hoit, Daniel , Hopkins, L. Nelson , Howington, Jay U., James, Robert F. , Jankowitz, Brian T. , Kan, Peter , Khalessi, Alex A, Kim, Louis J. , Langer, David J. , Mack, William J. , Mericle, Robert A., Ogilvy, Chris, Replogle, Robert, Riina, Howard A. , Saugaveau, Eric, Schirmer, Clemens M. , Spiotta, Alex, Sultan, Ali, Turner, Raymond D , Veznedaroglu, Erol, Welch, Babu G. , Davies, Jason M , Siddiqui, Adnan H , Schirmer, Clemens M , Waqas, Muhammad , Levy, Elad I. , Arthur, Adam Stephen , Grande, Andrew Walker , Hanel, Ricardó A. , Kim, Louis J. , Lanzino, Giuseppe , Levitt, Michael R. , Lopes, Demetrius K. , Mocco, J , Pandey, Aditya S , Ringer, Andrew J. , Rodriguez, Rafael, Tawk, Rabih G. , Thomas, Ajith J , White, Jonathan Samuel

Operative Neurosurgery | May 7, 2021 | Volume: 21 | Issue: 2 | Pages: E115-E116

10.1093/ons/opab124 | PMID 33956956 Get It

Abstract Intracranial atherosclerotic disease (ICAD) is a common cause of stroke. Antiplatelet therapy is the mainstay for symptomatic ICAD treatment. Endovascular management with submaximal angioplasty and/or intracranial stenting is reserved for patients with repeated ischemic events despite optimal medical therapy. We demonstrate intracranial angioplasty and stenting technique, technique indications, and sizing of stent and target vessel diameter. Stenting and angioplasty have been described in the Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis and Wingspan Stent System Post Market Surveillance trials. 1,2 Submaximal angioplasty has also been described. 3 This patient, who had been on dual antiplatelet therapy for several months, initially presented with occlusion of the left middle cerebral artery M2 inferior division and underwent mechanical thrombectomy with successful reperfusion. Postoperatively, the patient's symptoms did not improve. Medical management was optimized with heparin infusion. However, repeat stroke study demonstrated M2 inferior division reocclusion. A decision was made to proceed with intracranial angioplasty and stenting. P2Y12 levels were therapeutic. Under moderate conscious sedation, submaximal angioplasty of up to 80% of the normal M2 caliber was attempted. However, we observed persistent high-grade stenosis of the M2 inferior division. The major risk of crossing the lesion for angioplasty is vessel perforation. To safely perform this maneuver, we used a J-configured Synchro-2 microwire (Stryker). Because of the patient's recent thrombectomy, we also had prior tactile feedback about how much resistance was encountered while crossing the occlusion. We then deployed a balloon-mounted intracranial stent for optimal radial force across the stenotic area to restore perfusion. Postoperative computed tomography perfusion showed resolution of the previously noticed perfusion deficit. The patient gave informed consent for the procedures and video recording. Institutional review board approval was deemed unnecessary. Video. ©University at Buffalo Neurosurgery, September 2020. With permission.
Common Femoral Artery Access: 2-Dimensional Operative Video
Darwal, Maureen A, Binning, Mandy J., Bain, Mark, Bendock, Bernard, Boulos, Alan S. , Fessler, Richard D., Guterman, Lee R., Hoit, Daniel , Hopkins, L. Nelson , Howington, Jay U., James, Robert F. , Jankowitz, Brian T. , Kan, Peter , Khalessi, Alex A, Kim, Louis J. , Langer, David J. , Mack, William J. , Mericle, Robert A., Ogilvy, Chris, Replogle, Robert, Riina, Howard A. , Saugaveau, Eric, Schirmer, Clemens M. , Spiotta, Alex, Turner, Raymond D , Welch, Babu G. , White, Jonathan A. , Schirmer, Clemens M , Grande, Andrew Walker , Hanel, Ricardó A. , Kim, Louis J. , Lanzino, Giuseppe , Levitt, Michael R. , Lopes, Demetrius K. , Mocco, J , Rodriguez, Rafael, Siddiqui, Adnan H. , Aziz‐Sultan, Mohammad Ali , Thomas, Ajith J

Operative Neurosurgery | May 4, 2021 | Volume: 19 | Issue: 6 | Pages: E594-E594

10.1093/ons/opaa192 | PMID 34383930 Get It

Abstract Vascular access for cerebral angiography has traditionally been performed via the common femoral artery. It is crucial to obtain safe access to prevent complications that could lead to limb ischemia, groin hematoma, or retroperitoneal hematoma. This is especially true in neurointervention as many patients are anticoagulated or have received intravenous thrombolytics prior to their intervention. Special attention to anatomic landmarks, both grossly and radiographically, can help to assure safe access. The patient consented for this procedure. This video details rapid but safe femoral artery access in a patient undergoing emergent thrombectomy.
Carotid Stenting: Flow Reversal Technique: 2-Dimensional Operative Video
Domingo, Ricardo A. , Ravindran, Krishnan , Tawk, Rabih G. , Bain, Mark, Bendock, Bernard, Binning, Mandy J., Boulos, Alan S. , Crowley, Webster, Fessler, Richard D., Guterman, Lee R., Hoit, Daniel , Hopkins, L. Nelson , Howington, Jay U., James, Robert F. , Jankowitz, Brian T. , Kan, Peter , Khalessi, Alex A, Kim, Louis J. , Langer, David J. , Mack, William J. , Mericle, Robert A., Ogilvy, Chris, Replogle, Robert, Riina, Howard A. , Saugaveau, Eric, Schirmer, Clemens M. , Spiotta, Alex, Turner, Raymond D , Veznedaroglu, Erol, Welch, Babu G. , Tawk, Rabih G , Schirmer, Clemens M , Domingo, Ricardo A , Arthur, Adam Stephen , Grande, Andrew Walker , Hanel, Ricardó A. , Kim, Louis J. , Lanzino, Giuseppe , Levitt, Michael R. , Levy, Elad I. , Lopes, Demetrius K. , Mocco, J , Pandey, Aditya S , Ringer, Andrew J. , Rodriguez, Rafael, Siddiqui, Adnan H. , Aziz‐Sultan, Mohammad Ali , Thomas, Ajith J , White, Jonathan Samuel

Operative Neurosurgery | April 30, 2021 | Volume: 21 | Issue: 2 | Pages: E111-E112

10.1093/ons/opab119 | PMID 33929024 Get It

Abstract Management options for carotid stenosis include medical management, carotid endarterectomy, carotid stenting with distal filter protection, or stenting with either flow arrest or flow reversal techniques. 1 Flow reversal with transcarotid artery revascularization (TCAR) technique represents a hybrid approach with surgical access to the common carotid for endovascular placement of a stent in the internal carotid artery. This direct access to the carotid artery avoids navigating the challenging anatomy of the aortic arch with endovascular devices. 2 Compared to transfemoral stenting, TCAR possesses lower risk of transient ischemic attack and stroke, and compared to carotid endarterectomy, there is less risk of cranial neuropathy. 3,4 We present the case of an 87-yr-old man with recurrent severe stenosis (85%) of the right internal carotid artery. The patient had a remote history of bilateral endarterectomies for asymptomatic stenosis and was found with recurrence and progression of right internal carotid artery stenosis. Options were discussed and decision was made to proceed with TCAR after he consented for the procedure. The patient tolerated the procedure well with satisfactory revascularization. Exam remained unremarkable prior to discharge on postoperative day 1 and during follow-up at 1 mo. Patient consented to the publication of their image.
The Importance of Financial Metrics in Physician Funding and Performance Evaluation
Patrinely, James R. , Walker, Sallie, Glassman, Gabriella E. , Davis, Matthew J. , Khan, Umraz , Drolet, Brian C. , Forte, Antonio J. , Patrinely, J Randall, Walker, Sallie H, Abu-Ghname, Amjed, Perdikis, Galen, Forte, Antonio Jorge , Abu‐Ghname, Amjed , Perdikis, Galen

Plastic & Reconstructive Surgery | April 23, 2021 | Volume: 147 | Issue: 5 | Pages: 1213-1218

10.1097/prs.0000000000007882 | PMID 33890907 Get It

Background: Financial key performance indicators are often used to evaluate performance. Understanding of key performance indicators can be crucial for career advancement and bargaining leverage in resource negotiations. This study aimed to identify the most important key performance indicators used in surgical funding requests and understand how to use these metrics in clinical practice. Methods: In two tertiary medical centers, funding requests for surgeon gap support (2019 to 2020) and equipment (2017 to 2019) within departments of surgery were reviewed. The requesting department, approval status, and amount allotted were recorded. In requests for gap support, projections for contribution margin, operating room volume, charges, collections, and relative value units were tracked. Projected contribution margin and cost savings were recorded for equipment funding requests. Results: There were 40 gap support and 24 equipment requests, and all were approved. Most gap support requests included collections (90.0 percent), charges (87.5 percent), operating room cases (80.0 percent), relative value units (77.5 percent), and hospital contribution margin (77.5 percent). The most represented departments were general surgery (37.5 percent), neurosurgery (22.5 percent), and plastic surgery (15.0 percent). The departments that submitted the most equipment requests were general surgery (28.0 percent) and neurosurgery (28.0 percent). Most requests included projections for contribution margin (95.8 percent) and cost savings (87.4 percent). Projected hospital contribution margin correlated with the amount of funds allotted for surgeon support (r = 0.409; p = 0.022). Conclusions: This multicenter study identified the importance of using key performance indicators for a successful financial outcome in funding requests. In addition, the authors demonstrate the need for surgeons to understand their own key performance indicators. Surgeons should advocate for increased transparency to better understand their financial contributions and performance.
Intracranial Access: Dural Venous Sinus Stenting: 2-Dimensional Operative Video
Domingo, Ricardo A. , Ravindran, Krishnan , Kulakova, Katya, Tawk, Rabih G. , Bain, Mark, Bendock, Bernard, Binning, Mandy J., Boulos, Alan S. , Crowley, Webster, Fessler, Richard D., Guterman, Lee R., Hoit, Daniel , Hopkins, L. Nelson , Howington, Jay U., James, Robert F. , Jankowitz, Brian T. , Kan, Peter , Khalessi, Alex A, Kim, Louis J. , Langer, David J. , Mack, William J. , Mericle, Robert A., Ogilvy, Chris, Replogle, Robert, Riina, Howard A. , Saugaveau, Eric, Schirmer, Clemens M. , Spiotta, Alex, Sultan, Ali, Turner, Raymond D , Veznedaroglu, Erol, Welch, Babu G. , White, Jonathan, Tawk, Rabih G , Schirmer, Clemens M , Domingo, Ricardo A , Arthur, Adam Stephen , Grande, Andrew Walker , Hanel, Ricardó A. , Kim, Louis J. , Lanzino, Giuseppe , Levitt, Michael R. , Levy, Elad I. , Lopes, Demetrius K. , Mocco, J , Pandey, Aditya S , Ringer, Andrew J. , Rodriguez, Rafael, Siddiqui, Adnan H. , Thomas, Ajith J , White, Jonathan A.

Operative Neurosurgery | April 23, 2021 | Volume: 21 | Issue: 2 | Pages: E113-E114

10.1093/ons/opab120 | PMID 33891009 Get It

Abstract Cerebral venous sinus stenting has gained popularity in recent years as a safe and efficacious treatment of selected patients with idiopathic intracranial hypertension (IIH) and focal venous sinus stenosis.1–3 - 3 The main goal of treatment is to prevent visual loss, and often patients report resolution of headache and visual symptoms within 21 mo of mean follow-up.4–8 - 8 We present the case of a 57-yr-old woman with medically refractory IIH, bilateral sinus stenosis, and a mass lesion causing stenosis on the left. Venous angiogram with pressure monitoring was completed with the patient awake, which showed a significant pressure gradient on the right (19 mm Hg) and borderline gradient on the left (8 mm Hg). Options were reviewed and decision was made to proceed with the treatment of the right-sided stenosis with stenting and continue with the observation of the lesion on the left to prevent further visual deterioration. The patient consented for the procedure, and she tolerated the procedure well. Neurological exam remained at baseline, and she was discharged home on post-operative day #1. At 2 mo’s follow-up, the patient reported improvement in headaches and remained intact neurologically.
A Cognitive Psychometric Investigation of Word Production and Phonological Error Rates in Logopenic Progressive Aphasia
Petroi, Diana, Walker, Grant M. , Hickok, Gregory , Josephs, Keith A. , Duffy, Joseph R.

American Journal of Speech-Language Pathology | April 19, 2021 | Volume: 30 | Issue: 3 | Pages: 1194-1202

10.1044/2021_ajslp-20-00221 | PMID 33872514 Get It

Purpose This study investigated the relationship between word production rates (WPRs) and phonological error rates (PERs) in generative and responsive tasks in logopenic progressive aphasia (lvPPA). We examined whether a portion of the reduced WPR during generative tasks related directly to phonological impairments affecting PER on all tasks, irrespective of other task differences that contributed to WPR. Method Two cognitive psychometric models were hypothesized and fit to the total number of words produced and the number of phonological errors produced by 22 participants on 10 tasks. Bayesian inference was used to construct posterior distributions of participant ability and task difficulty parameters. Model fit statistics were compared. Association strengths for average generative WPR and average responsive PER were also evaluated with linear least-squares regression. Results Average generative WPR and average responsive PER were significantly associated ( r = −.77, p = .00002). A cognitive psychometric model that assumed reduced WPR on generative tasks reflects a portion of general phonological impairment yielded better fit than a model that ignored performance differences between generative and responsive tasks. Generative fluency tasks that elicited few phonological errors still reflected phonological impairment, via suppression. Individual participants were estimated to suppress between 62% and 93% of phonological errors on generative tasks that would have emerged on responsive tasks. Conclusions Suppression of phonological errors may present as decreased WPR on generative tasks in lvPPA. Failure to account for this suppression tendency may lead to overestimation of phonological ability. The findings indicate the need to account for task demands in assessing lvPPA.
Endovascular Treatment of Basilar Bifurcation Aneurysms With PulseRider-Assisted Coiling: 2-Dimensional Operative Video
Sattur, Mithun G. , Kasab, Sami Al , Spiotta, Alejandro M , Bain, Mark, Bendock, Bernard, Binning, Mandy J., Boulos, Alan S. , Crowley, Webster, Fessler, Richard D., Guterman, Lee R., Hoit, Daniel , Hopkins, L. Nelson , Howington, Jay U., James, Robert F. , Jankowitz, Brian T. , Kan, Peter , Khalessi, Alex A, Kim, Louis J. , Langer, David J. , Mack, William J. , Mericle, Robert A., Ogilvy, Chris, Replogle, Robert, Riina, Howard A. , Saugaveau, Eric, Schirmer, Clemens M. , Spiotta, Alex, Sultan, Ali, Turner, Raymond, Veznedaroglu, Erol, Welch, Babu G. , White, Jonathan, Spiotta, Alejandro M , Schirmer, Clemens M , Porto, Guilherme , Arthur, Adam Stephen , Grande, Andrew Walker , Hanel, Ricardó A. , Kim, Louis J. , Lanzino, Giuseppe , Levitt, Michael R. , Levy, Elad I. , Lopes, Demetrius K. , Mocco, J , Pandey, Aditya S , Ringer, Andrew J. , Rodriguez, Rafael, Siddiqui, Adnan H. , Tawk, Rabih G. , Thomas, Ajith J , White, Jonathan A.

Operative Neurosurgery | April 17, 2021 | Volume: 21 | Issue: 2 | Pages: E109-E110

10.1093/ons/opab102 | PMID 33861344 Get It

Abstract Wide-necked bifurcation aneurysms pose technical and anatomical challenges to endovascular treatment, which make the simpler assisted (balloon or single stent) coiling techniques less effective. 1 Consequently, unique endovascular solutions to treat such aneurysms have been devised. 2,3 One such device is PulseRider (Cerenovus, New Brunswick, New Jersey), which is designed to provide neck support for a coil mass while protecting the bifurcation. 3 The device comprises a body or stem that is deployed in the parent artery and a saddle component that sits at the aneurysm neck to keep the coil mass away from the bifurcation. There are several technical nuances involved in successful use of the device during positioning, deployment, and detachment. 3 We present a surgical video detailing the steps of PulseRider-assisted coiling of unruptured basilar bifurcation (or basilar apex) aneurysms. The first case highlights index treatment at diagnosis and the second showcases treatment of a recurrent basilar apex aneurysm. Both patients provided informed consent to the procedure. We also briefly discuss the rationale for treating basilar apex aneurysms. 4,5
Middle Cerebral Artery Thrombectomy: Clinical Findings and Technical Pearls: 2-Dimensional Operative Video
Rangwala, Shivani D. , Selvan, Pradeep, Tenser, Matthew, Mack, William J. , Bain, Mark, Bendock, Bernard, Binning, Mandy J., Boulos, Alan S. , Crowley, Webster, Fessler, Richard D., Guterman, Lee R., Hoit, Daniel , Hopkins, L. Nelson , Howington, Jay U., James, Robert F. , Jankowitz, Brian T. , Kan, Peter , Khalessi, Alex A, Kim, Louis J. , Langer, David J. , Mericle, Robert A., Ogilvy, Chris, Replogle, Robert, Riina, Howard A. , Saugaveau, Eric, Schirmer, Clemens M. , Spiotta, Alex, Sultan, Ali, Turner, Raymond D , Veznedaroglu, Erol, Welch, Babu G. , Schirmer, Clemens M , Arthur, Adam Stephen , Grande, Andrew Walker , Hanel, Ricardó A. , Kim, Louis J. , Lanzino, Giuseppe , Levitt, Michael R. , Levy, Elad I. , Lopes, Demetrius K. , Mocco, J , Pandey, Aditya S , Ringer, Andrew J. , Rodriguez, Rafael, Siddiqui, Adnan H. , Tawk, Rabih G. , Thomas, Ajith J , White, Jonathan Samuel

Operative Neurosurgery | April 17, 2021 | Volume: 21 | Issue: 2 | Pages: E107-E108

10.1093/ons/opab101 | PMID 33861327 Get It

Abstract Mechanical thrombectomy as a treatment for large vessel occlusion to achieve rapid revascularization is supported in the literature. 1-3 The presenting symptoms will localize to functions of the ischemic area. The middle cerebral artery (MCA) supplies areas of the frontal, temporal, and parietal cortices, as well as the basal ganglia. Occlusion of the MCA will present with contralateral hemiplegia, sensory loss, and, if the dominant hemisphere is involved, language deficits. We present a right-hand-dominant 79-yr-old female with right MCA syndrome—her last known well time was 1.5 h prior to presentation. Her NIH (National Institutes of Health) Stroke Scale was 16, most notable for left hemiplegia. Although the patient presented early in the clinical time course, as part of our institution protocol, a computed tomography (CT) head, CT perfusion, and CT angiogram (CTA) were performed. CT head did not demonstrate acute hemorrhage, so she received intravenous tissue plasminogen activator. CTA demonstrated a right MCA occlusion and CT perfusion suggested a large area of salvageable tissue, so she was taken to the angiography suite for mechanical thrombectomy. Angiography of the right internal carotid artery (ICA) showed MCA occlusion (insular segment). A thrombectomy device was deployed over the area of occlusion and allowed to engage for 5 min. An aspiration catheter was advanced over the stentriever up against the clot. The stentriever device was withdrawn under continuous aspiration and follow-up angiography showed complete reperfusion. The patient demonstrated improvement and was eventually discharged to an inpatient rehabilitation center. Patient provided consent for photography per university protocol. Institutional review board (IRB) approval was not needed for the single-patient data included in this report.
Asymmetry of Hippocampal Tau Pathology in Primary Age-Related Tauopathy and Alzheimer Disease
Walker, Jamie M. , Fudym, Yelena, Farrell, Kurt , Iida, Megan A., Bieniek, Kevin F. , Crary, John F. , Richardson, Timothy E. , Farrell, Kurt , Seshadri, Sudha , White, Charles L.

Journal of Neuropathology & Experimental Neurology | April 17, 2021 | Volume: 80 | Issue: 5 | Pages: 436-445

10.1093/jnen/nlab032 | PMID 33860327 Get It

Abstract Primary age-related tauopathy (PART) is a neurodegenerative entity defined as neurofibrillary degeneration generally restricted to the medial temporal region (Braak stage I–IV) with complete or near absence of diffuse and neuritic plaques. Symptoms range in severity but are generally milder and later in onset than in Alzheimer disease (AD). Recently, an early predilection for neurofibrillary degeneration in the hippocampal CA2 subregion has been demonstrated in PART, whereas AD neuropathologic change (ADNC) typically displays relative sparing of CA2 until later stages. In this study, we utilized a semiquantitative scoring system to evaluate asymmetry of neurofibrillary degeneration between left and right hippocampi in 67 PART cases and 17 ADNC cases. 49% of PART cases demonstrated asymmetric findings in at least one hippocampal subregion, and 79% of the asymmetric cases displayed some degree of CA2 asymmetry. Additionally, 19% of cases revealed a difference in Braak score between the right and left hippocampi. There was a significant difference in CA2 neurofibrillary degeneration (p = 0.0006) and CA2/CA1 ratio (p < 0.0001) when comparing the contralateral sides, but neither right nor left was more consistently affected. These data show the importance of analyzing bilateral hippocampi in the diagnostic evaluation of PART and potentially of other neurodegenerative diseases.
A Simple and Quick Method for Loading Proteins in Extracellular Vesicles
Busatto, Sara , Iannotta, Dalila , Walker, Sierra A. , Marzio, Luisa Di , Wolfram, Joy , Di Marzio, Luisa , Wolfram, Joy

Pharmaceuticals | April 13, 2021 | Volume: 14 | Issue: 4 | Pages: 356

10.3390/ph14040356 | PMID 33924377 Get It

Extracellular vesicles (EVs) mediate intercellular transport of biomolecular cargo in the body, making them promising delivery vehicles for bioactive compounds. Genetic engineering of producer cells has enabled encapsulation of therapeutic proteins in EVs. However, genetic engineering approaches can be expensive, time-consuming, and incompatible with certain EV sources, such as human plasma and bovine milk. The goal of this study was to develop a quick, versatile, and simple method for loading proteins in EVs post-isolation. Proteins, including CRISPR associated protein 9 (Cas9), were bound to cationic lipids that were further complexed with MDA-MB-231 cell-derived EVs through passive incubation. Size-exclusion chromatography was used to remove components that were not complexed with EVs. The ability of EVs to mediate intracellular delivery of proteins was compared to conventional methods, such as electroporation and commercial protein transfection reagents. The results indicate that EVs retain native features following protein-loading and obtain similar levels of intracellular protein delivery as conventional methods, but display less toxicity. This method opens up opportunities for rapid exploration of EVs for protein delivery.