Neurosurgery Commons^™

Intravenous Thrombolysis Beyond The Conventional Time Window For Acute Ischemic Stroke: A Systematic Review And Meta-Analysis, Shaan Patel, Shiva A. Nischal, Kush M. Kale, Michael R. Gooch, Stavropoula I. Tjoumakaris, Pascal Jabbour

Department of Neurosurgery Faculty Papers

IMPORTANCE: Intravenous thrombolysis (IVT) is an established therapy for acute ischemic stroke when administered within 4.5 hours of symptom onset. However, many patients present beyond this window or with unknown onset, and recent randomized clinical trials (RCTs) have evaluated whether imaging-selected patients may benefit from thrombolysis in the extended window.

OBJECTIVE: To evaluate the functional and safety outcomes associated with IVT administered 4.5 hours or more after stroke onset.

DATA SOURCES: PubMed, Embase, and Cochrane Central Register of Controlled Trials were systematically searched from database inception through March 3, 2026.

STUDY SELECTION: RCTs enrolling adults with acute ischemic stroke treated …

Safety Of Early Discharge And Abbreviated Nimodipine Course In Patients With Good-Grade Aneurysmal Subarachnoid Hemorrhage, Patrick R. Toyota, Alexander D. Rebchuk, Michael A. Rizzuto, Hugh Mchugh, Kelsey Cruz, Charles S. Haw, Gary J. Redekop, Peter Gooderham

Department of Neurosurgery Faculty Papers

Aneurysmal subarachnoid hemorrhage (aSAH) remains a devastating cerebrovascular emergency associated with substantial morbidity and mortality. Current guidelines recommend 14-21 days of inpatient monitoring and a 21-day course of nimodipine following aSAH. This retrospective study evaluates early outcomes early discharge (≤14 days post-ictus) and an abbreviated nimodipine course in highly selected patients with good-grade aSAH managed under a standardized institutional protocol. Consecutive patients enrolled in the Vancouver Ruptured Aneurysm Database (VRAD) at Vancouver General Hospital between 2022 and 2025 were included. Inclusion criteria were good-grade aSAH (WFNS Grade I-III) and discharge home within 14 days of ictus. The primary outcome was …

Spontaneous Intracranial Hypotension With Negative Brain Mri Findings: A Systematic Review Of Diagnostic Strategies And Clinical Outcomes, Marina Romozzi, Giuseppe Garignano, Valid Rastegar, Francesco Onorati, Catello Vollono, Federico Tosto, Masahito Katsuki, Yasuhiko Matsumori, Francesco Signorelli

Student Papers, Posters & Projects

BACKGROUND: Spontaneous intracranial hypotension (SIH) is a debilitating syndrome typically characterized by orthostatic headache and classic brain MRI findings. However, brain MRI abnormalities are indirect manifestations of cerebrospinal fluid (CSF) volume depletion rather than direct evidence of the leak, and some patients may present with unrevealing or absent typical brain MRI findings, posing a considerable diagnostic challenge.

METHODS: A comprehensive search of PubMed/Medline, Web of Science, and Scopus was conducted to perform a systematic review, according to PRISMA guidelines, analyzing the available evidence on MRI-negative SIH (patients without typical SIH findings on their initial brain MRI), including its clinical features, …

Impact Of Middle Meningeal Artery Embolization Timing On Chronic Subdural Hematoma Resolution And Functional Outcomes, Bluyé Demessie, Muhammed Amir Essibayi, Hamza Adel Salim, Alireza Karandish, Nathan Farkas, Deepak Khatri, Neil Haranhalli, Amanda Baker, Richard Zampolin, Allan L Brook, Seon-Kyu Lee, Nimer Adeeb, James Grist, Fulvio Zaccagna, Yan-Lin Li, Davide Simonato, Diego Alejandro Ortega, Nicole Cancelliere, Jose Danilo Diestro, Dhairya Lakhani, Joseph Carnevale, Craig Schreiber, Atakan Orscelik, Zachary Abecassis, Spencer Raub, Georgios Sioutas, Giancarlo Salsano, Svetlana Kvint, Andrew Falzon, Vance Cantrell, Brian Holliday, Jefferson Abaricia, Pedram Maleknia, Leonardo Cruz-Criollo, Samantha Schimmel, Basel Musmar, Matthew Alexander, Jorge Rios Zermeno, Koul Prateeka, Ahmed Aljuboori, Dominik Vollherbst, Domagoj Gajski, Jared Cooper, Rahim Abo Kasem, Sami Al Kasab, Alejandro Spiotta, Fawaz Al-Mufti, Vladimir Kalousek, Markus Möhlenbruch, Luca Scarcia, Clemens Schirmer, Thien Huynh, Rabih Tawk, Fabio Settecase, Stavropoula Tjoumakaris, Pascal Jabbour, Kunal Vakharia, Mario Zanaty, Santiago Ortega-Gutierrez, Jesse Jones, Marco Colasurdo, Hussein Nasser, Sri Hari Sundararajan, Pascal Mosimann, Erez Nossek, Eytan Raz, Lucio Castellan, Bruno Del Sette, Caterina Michelozzi, Davide Saraceno, Pietro Panni, Visish Srinivasan, Jan-Karl Burkhardt, Gaultier Marnat, Pietro Mario Santini, Michael Levitt, Giuseppe Lanzino, Waleed Brinjikji, Jared Knopman, Tareq Kass-Hout, Julian Spears, Thomas Marotta, Max Wintermark, Vitor Mendes Pereira, Maurizio Fuschi, Adam Dmytriw, David Altschul

Department of Neurosurgery Faculty Papers

BACKGROUND AND PURPOSE: Chronic subdural hematoma (cSDH) affects approximately 20 per 100,000 individuals annually, with surgical recurrence rates of 10-20%. Middle meningeal artery embolization (MMAE) has emerged as a promising minimally invasive treatment, but the optimal timing remains unclear. We evaluated the association between MMAE timing and radiological and functional outcomes in cSDH.

METHODS: We conducted a retrospective multicenter international cohort study across 33 centres, including patients who underwent MMAE for cSDH between January 2018 and December 2024. Patients were stratified by timing from diagnosis: Q1 (≤1 day), Q2 (2 days), Q3 (3-6 days), and Q4 (>6 days). The …

Development Of An Educational Curriculum For The Surgical Implantation Of Dbs Systems, David Bieber, Rany T Abdallah, Alaa Ab-Elsayed, Adam R Burkey, Dario J Englot, Kunal Gupta, Charles N Munyon, Casey H Halpern, Kai J Miller, Joshua M Rosenow, Ahmed M Raslan, Konstantin V Slavin, Jennifer A Sweet, Sameer Sheth, Nestor Tomycz, Ashwin Viswanathan, Chengyuan Wu, Jeffrey S Raskin

Faculty, Staff and Students Publications

Background: Deep-brain stimulation (DBS) systems are implanted for movement disorders, epilepsy, and psychiatric conditions. Neurologic surgery remains the only discipline credentialed to implant DBS devices, although significant practice variation exists, partly due to heterogeneous training. The North American Neuromodulation Society (NANS) education committee offers a granular recommendation for the progression of an early learner through the practitioner level. It is contextualized within the six-core competency rubric for the surgical implantation of DBS devices.

Materials and methods: Guided by the Accreditation Council for Graduate Medical Education (ACGME) core competencies, a subcommittee of the NANS education committee met virtually and in-person over …

A Nationwide Central Diagnosis For Pediatric Cns Tumors In Japan: The Jccg Brain Tumor And Pathology Committees, Yoshiko Nakano, Junko Hirato, Takako Yoshioka, Tetsuya Takimoto, Sumihito Nobusawa, Kaishi Satomi, Ran Tomomasa, Seiji Yamada, Taku Homma, Shoh Sasaki, Ayako Yamazaki, Maki Sakaguchi, Yasuhide Takeuchi, Nei Fukazawa, Kai Yamasaki, Kohei Fukuoka, Yui Shinohara Kimura, Yuki Nagayama, Yohei Inoue, Akira Miyahira, Ema Yoshioka, Asako Katsuma, Hayato Fukusumi, Tomoko Shofuda, Yuko Hibiya, Yuko Matsushita, Mai Honda Kitahara, Yuki Yomoda, Miho Kato, Michael D Taylor, Yasuhito Arai, Tatsuhiro Shibata, Hiroaki Sakamoto, Keita Terashima, Yoshiki Arakawa, Toshihiro Kumabe, Ryo Nishikawa, Junichi Hara, Yonehiro Kanemura, Koichi Ichimura

Faculty, Staff and Students Publications

In 2016, the Japan Children's Cancer Group launched a nationwide research initiative to provide central diagnosis incorporating pathology review and molecular profiling for pediatric central nervous system (CNS) tumors. Over the first eight years, 2224 cases were registered. Non-next-generation sequencing analyzes, such as pyrosequencing and NanoString, were routinely performed, mainly for glioma, medulloblastoma, and ependymoma. Additional analyzes, including methylation profiling and RNA sequencing, were conducted for selected diagnostically challenging cases. The most common diagnoses were low-grade glioma (26%), medulloblastoma (18%), germ cell tumor (16%), high-grade glioma (12%), and ependymoma (11%). Diagnostic or targetable alterations were detected in nearly half of …

Association Of Cerebrovascular Center Volume With Patient Outcomes, Stacey Quintero Wolfe, Justin R. Mascitelli, Kyle Fargen, Peter Kan, Ketan Bulsara, Christopher P. Kellner, Brian M. Howard, Michael R. Levitt, Rocco Armonda, Joshua Osbun, Clemens Schirmer, Mark Bain, William J. Mack, Stavropoula Tjoumakaris, Adam Arthur

Department of Neurosurgery Faculty Papers

Current guidelines acknowledge the importance of both microsurgical and neuroendovascular expertise in the treatment of cerebrovascular disease. To achieve optimal care for these patients, it is becoming increasingly evident that procedural volumes impact patient outcomes. This is demonstrated across various cerebrovascular diseases.In this literature review, we demonstrate the association of volume with patient outcomes across multiple cerebrovascular disease states and interventions. Microsurgical aneurysm clipping remains essential even with the rise of endovascular therapy and mortality and patient-safety indicator events are clearly lower at high-volume centers for both ruptured and unruptured aneurysms. Likewise, patients undergoing surgery for cerebrovascular malformations and carotid …

Treatment Times For Rural And Urban Patients With Aneurysmal Subarachnoid Hemorrhage In A Provincial Hub-And-Spoke Network, Alexander D. Rebchuk, Hugh Mchugh, Michael A. Rizzuto, David Chen, Kelsey Cruz, Erik N. Vu, Peter A. Gooderham

Department of Neurosurgery Faculty Papers

BACKGROUND: Following aneurysmal subarachnoid hemorrhage (aSAH), aneurysm rebleeding leads to very poor clinical outcomes. Ruptured aneurysms must be urgently secured either by open microsurgery or endovascular techniques to prevent re-rupture. The objective of this study was to compare time-to-treatment and functional outcomes following aSAH between rural and urban patients treated at a quaternary neurosurgical centre with a large geographical catchment.

METHODS: We analyzed patients enrolled in the Vancouver Ruptured Aneurysm Database (VRAD) between December 2022 and September 2025. Demographic, clinical, radiographic, treatment and functional outcomes were compared between groups. Time from ictus-to-presentation, ictus-to-neurosurgical centre, ictus-to-treatment and transfer times were collected. …

Beyond Coiling: A Comparative Analysis Of Survey-Reported Preferences For Endovascular Cerebral Aneurysm Occlusion, Sanjana R Salwi, Thilan Tudor, Oleg Shekhtman, Georgios S. Sioutas, Pious D. Patel, Irina-Mihaela Matache, Mohamed Salem, Sonia Ajmera, Sandeep Kandregula, Jan-Karl Burkhardt, Visish M. Srinivasan

Department of Neurosurgery Faculty Papers

BACKGROUND: Aneurysm treatment options are rapidly evolving, as evidenced by the recent introduction and widespread adoption of flow diversion and intrasaccular devices. However, there is a need to understand how these newer technologies are used for difficult-to-treat aneurysms. The main aims of this study were to investigate the variation in aneurysm treatment recommendations among neurosurgeons, interventional radiologists, and interventional neurologists and to generally describe trends in endovascular treatment.

METHODS: In this survey-based study conducted from June to September 2024, participants were presented with clinical vignettes and asked to choose preferred treatment options, with responses analyzed based on demographic variables including …

Treatment Of Hemifacial Spasm With Endovascular Stenting Of The Vertebral Artery, Maximillian Feygin, Marcus Shee-Tzer Wong, Andrew Zhang, Ashwin Viswanathan, Omar Tanweer

Faculty, Staff and Students Publications

Background and importance: Hemifacial spasm (HFS) is a movement disorder characterized by involuntary spasms of the facial muscles that can lead to debilitating symptoms and is typically caused by vascular compression. Classically, microvascular decompression of the offending vessel is the gold standard; however, in certain cases, microvascular decompression may have increased risk because of patient comorbidities and underlying anatomy. In this report, we describe a unique endovascular approach with flow diversion for the treatment of HFS.

Clinical presentation: A 70-year-old woman presented to the clinic with a 5-year history of HFS on the right side progressing from the eye to …

Human Neuronal Firing Varies With The Frequency Of Local Field Potential Oscillations, Zahra Jourahmad, Raissa K Mathura, Layth S Mattar, Melissa C Franch, Danika L Paulo, Mohammed Hasen, Nicole R Provenza, Benjamin Y Hayden, Sameer A Sheth, Eleonora Bartoli, Andrew J Watrous

Faculty, Staff and Students Publications

Neural oscillations play a critical role in shaping neuronal firing patterns. While phase-locked neuronal firing ("phase tuning") has been extensively studied in animal models and human invasive recordings, much less is known about whether neurons show preferential firing at specific oscillatory frequencies, termed frequency tuning. Here, we employ human intracranial recordings across several brain regions including hippocampus, entorhinal cortex, anterior and posterior cingulate cortex, and orbitofrontal cortex to test the hypothesis that neurons exhibit frequency-specific firing. We analyzed 357 single units recorded simultaneously with local field potentials in 19 neurosurgical patients during awake resting. We estimated the instantaneous frequency of …

Comprehensive Proteogenomic Characterization Reveals Clinically Relevant Molecular Subtypes Associated With Medulloblastoma Progression, Seong-Min Park, Kyung-Hee Kim, Jong Hyuk Yoon, Fulvio D'Angelo, Seung Ah Choi, Chan Il Kim, Harim Koo, Seungmin Park, Hyondeog Kim, Sreeja Sundara Raj, Sung Soo Kim, Ae Kyung Park, Eun Jung Koh, Seong-Ik Kim, Yu-Mi Shim, Lee Kwang-Hoon, Eric Eunshik Kim, Ji Hoon Phi, Yeon Suk Jo, Do Hyun Nam, Daehee Hwang, Do Young Hyeon, Sunghyun Huh, Hyung Joon Kwon, Seokjun Ha, Sanha Park, Hyeji Shin, Jeong Taik Kwon, Heon Yoo, Ho-Shin Gwak, Michael D Taylor, Bong Jin Park, Jason K Sa, Youngwook Kim, Antonio Iavarone, Sung-Hye Park, Seung-Ki Kim, Jong Bae Park

Faculty, Staff and Students Publications

Current treatment strategies for medulloblastoma remain ineffective owing to extensive tumor heterogeneity. We generated five platforms of omics data including liquid chromatography and mass spectrometry-based proteome and performed integrated multi-omic characterization to improve the conventional molecular classification of medulloblastoma. We identified seven refined distinct subtypes. The sonic hedgehog (SHH) group was reclassified into two subgroups, SHHα and SHHβ, whereas group 4 was divided into three subgroups, G4α, G4β, and G4γ. SHH and group 4 subtypes exhibit two distinct neuronal differentiation trajectories: granular neuron and unipolar brush cell differentiation (SHHβ and G4γ, respectively), both of which associated with more favorable clinical …

Minimally Invasive Versus Burr Hole Craniostomy For Chronic Subdural Haematoma Evacuation: A Systematic Review And Meta-Analysis, Shaan Patel, Shiva A. Nischal, Angelette Mendonca, Kush M. Kale, Santosh Guru, Pious D. Patel, Kevin Hines, Jack Jallo, Srinivas K. Prasad

Department of Neurosurgery Faculty Papers

BACKGROUND: Minimally invasive surgery (MIS) has emerged as an appealing alternative to burr hole craniostomy (BHC) for chronic subdural haematoma (cSDH), offering reduced operative trauma and anaesthetic exposure. However, whether these procedural advantages translate into comparable outcomes remains uncertain. This systematic review and meta-analysis aimed to compare the safety, effectiveness, and procedural performance of MIS versus BHC for cSDH evacuation, with attention to device-specific outcomes.

METHODS: A systematic search of PubMed, Embase, and CENTRAL (10th November 2025) identified randomised and observational studies directly comparing MIS techniques, including twist-drill craniostomy (TDC), subdural evacuating port systems (SEPS), and YL-1 devices, with BHC. …

Multiple Intracranial Aneurysms: An International Consensus Statement, Stavropoula Tjoumakaris

Department of Neurosurgery Faculty Papers

Introduction: Multiple intracranial aneurysms (MIAs) pose diagnostic and therapeutic challenges, and widely used rupture-risk scores have not been validated for this subgroup. Research question: To develop expert-based recommendations for the diagnosis, rupture-risk assessment, treatment selection, and follow-up of patients with MIAs. Material and methods: A modified Delphi process was conducted. After topic generation from the literature, iterative questionnaires were administered anonymously online to invited experts. Consensus was prespecified as ≥70% agreement. Twenty-six of 35 invitees (74.3%) completed the survey. Results: Consensus identified the ruptured lesion in aneurysmal subarachnoid hemorrhage (aSAH) using computed tomographic angiography (CTA) and 3D rotational digital subtraction …

Optimal Timing Of Ventriculoperitoneal Shunt Insertion Relative To Cranioplasty Post-Decompressive Craniectomy: A Frequentist Network Meta-Analysis, Shaan Patel, Shiva A. Nischal, Kush M. Kale, Pious D. Patel, James S. Harrop, Jack Jallo, Srinivas K. Prasad

Department of Neurosurgery Faculty Papers

OBJECTIVE: Optimal timing of ventriculoperitoneal shunting (VPS) relative to cranioplasty (CP) after decompressive craniectomy remains controversial. VPS may be performed before, during, or after CP, but no consensus exists on which sequence minimizes complications. We performed a systematic review and network meta-analysis to compare the safety profiles of pre-, simultaneous, and post-CP shunting.

METHODS: We searched PubMed/MEDLINE, Embase, and CENTRAL from inception to October 2025. Eligible studies directly compared at least two timing strategies in patients undergoing both CP and VPS. Primary outcomes included overall complications, reoperation, infection, and intradural bleeding. Secondary outcomes included shunt-related and other procedure-specific adverse events. …

Nuclear Export As A Therapeutic Vulnerability In Zfta-Rela Ependymoma, Siri M Ippagunta, Amir Arabzade, Srinidhi Varadharajan, Erik Emanus, Amanda Bland, Alisha Kardian, Nicholas Laboe, Hua Sun, Tuyu Zheng, Amelia Hancock, Mark Zhai, Emma Caesar, Maxwell Park, Wilda Orisme, Melissa Johnson, Brittany Rodgers, Gregory H Turner, Jeffrey Steinberg, Burgess Freeman, Martine F Roussel, Anang Shelat, Richard Kriwacki, Thomas E Merchant, Benjamin Deneen, Michael D Taylor, Sameer Agnihotri, Shondra Pruett-Miller, Jacob A Steele, Anoop Murthy Kavirayani, David W Ellison, Arzu Onar-Thomas, Giles Robinson, Stephen C Mack, Kelsey C Bertrand

Faculty, Staff and Students Publications

Background: Ependymoma (EPN) is the third most common pediatric brain tumor with no targeted therapies available to patients. In supratentorial ependymoma, the most frequent driver alteration is a gene fusion between ZFTA and RELA (denoted ZR), leads to constitutive localization of ZR in the nucleus. Because ZR is not currently druggable, we tested whether ZR expression leads to aberrant protein interactions that could represent therapeutic vulnerabilities.

Methods: Using CRISPR-Cas9 pooled screening, we identified many novel druggable ZR interacting proteins including XPO1, CARM1, SMARCA4, and CDK1. We focused on the nuclear export protein (XPO1), given the ability of most XPO1 inhibitors …

Combined Middle Meningeal Artery Embolisation And Subdural Evacuation Port System Drainage For Chronic Subdural Haematoma: A Systematic Review, Single-Arm Meta-Analysis, Meta-Regression, And Cost-Benefit Analysis, Shiva A. Nischal, Santosh Guru, Shaan Patel, Ashviniy Thamilmaran, Mary Murphy

Department of Neurosurgery Faculty Papers

BACKGROUND: Chronic subdural haematoma (cSDH) is an increasingly prevalent condition in older, anticoagulated, and medically frail patients, in whom recurrence and perioperative risk remain substantial despite standard surgical evacuation. Growing recognition of cSDH as an angiogenic, inflammatory disorder has prompted interest in minimally invasive strategies that combine mechanical decompression with targeted modulation of the underlying vascular pathology. This study aimed to evaluate the safety, effectiveness, and health-economic profile of combined middle meningeal artery embolisation and subdural evacuation port system (MMAE-SEPS) drainage for cSDH, compared with conventional burr-hole evacuation.

METHODS: MEDLINE, Embase, and CENTRAL were searched from inception to 24th August …

When The Eagle Strikes The Vein: A Case Of Styloid-Induced Venous Sinus Thrombosis, Neud Kiros, Ahmad Chehab, Abeer Abukamil, Ali Luqman, Kamil Abu-Shaban, Mehdy Haidar, Ay-Ming Wang

Conference Presentation Abstracts

Clinical History 41-year-old male with no prior relevant medical history presented to the emergency department with severe neck pain and occipital headaches radiating bilaterally to the temporal regions. He also reported diplopia and “tunnel vision.” He had presented two weeks earlier with similar symptoms and was advised outpatient follow-up. Initial CT head and cervical spine were unremarkable. Imaging Findings Brain MRI/MRV demonstrated heterogeneous signal and enhancement in the left transverse and sigmoid sinuses and jugular bulb, initially thought to reflect possible motion artifact. However, CT venography was recommended for further assessment. The MRI also showed subtle left posterior occipital subdural …

Changes In Opioid Prescribing Patterns In Opioid Naive Patients Can Translate To Improved Outcomes In The Opioid Non-Naive Patients With Anterior Cervical Surgery: A Michigan Spine Surgery Improvement Collaborative (Mssic) Study, Anisse Chaker, Geoff Kahn, Michael Melhem, Jian-Hui Hu, Kari Jarabek, Heegook Yeo, Bhargav Ayloo, Trevor Ruesch, Adam Junn, Jad Khalil, Kenneth Easton, Richard Easton, Doris Tang, Miguelangelo Perez-Cruet, Noojan Kazemi, Ilyas Aleem, Muwaffak Abulhak, David Nerenz, Victor Chang

Conference Presentation Abstracts

Introduction: Though often necessary for adequate analgesia after spine surgery, continued opioid use can lead to chronic dependency. The Michigan Spine Surgery Improvement Collaborative (MSSIC) has demonstrated in prior work the promise of utilizing a multi-institutional morphine milliequivalent (MME) cutoff for elective anterior cervical surgery in the opioid naıve population. However, the effect of this cutoff in patients who were already on opioids pre-operatively have not previously been studied. The goal of this study was to evaluate whether changes in prescribing patterns in the opioid naıve population would also translate to the non-naıve populations, and whether the non-naıve population would …

Implementation Of A Multi-Institutional Enhanced Recovery After Surgery (Eras) For Elective Spine Surgery: Two-Year Michigan Spine Surgery Improvement Collaborative (Mssic) Experience, Anisse Chaker, Kylie Springer, Kari Jarabek, Michael Melhem, Heegook Yeo, Jian-Hui Hu, Jad Khalil, Kenneth Easton, Richard Easton, Doris Tong, Miguelangelo Perez-Cruet, Noojan Kazemi, Ilyas Aleem, Muwaffak Abulhak, Victor Chang

Conference Presentation Abstracts

Introduction: Enhanced Recovery After Surgery (ERAS) protocols have been introduced to several surgical specialties with the intention to reduce peri-operative adverse events and improve various health-system quality metrics including length of stay and patient satisfaction. Though this has been studied in the setting of spine surgery, the vast majority are single institution protocols biased toward academic teaching hospitals. There is a paucity of literature studying the utilization of a multi-institutional ERAS protocols that is applicable to community hospitals without associated training programs. We present the Michigan Spine Surgery Improvement Collaborative (MSSIC) two-year experience implementing a multi-institutional ERAS protocol for elective …