Surgery
Showing 81-100 of 151 Results
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Adel Mutahar
Postdoctoral Scholar, General and Vascular Surgery
BioDr. Adel Z. I. Mutahar is a postdoctoral researcher in the Department of Surgery at Stanford University, working under the mentorship of Dr. Frederick M. Dirbas. His research focuses on translational breast cancer biology and emerging radiotherapy technologies, with an emphasis on tumor–microenvironment interactions, immuno-oncology, and preclinical therapeutic development. His academic journey spans three countries—beginning in Yemen, advancing through India, and now progressing at Stanford—reflecting his commitment to impactful cancer research and global scientific advancement.
Dr. Mutahar began his career in Yemen, earning his Bachelor’s degree in Medical Laboratory Sciences before joining Abs Community College as a faculty member. From 2007–2013, he held several academic leadership roles, including Academic Director, Head of Evaluation, and Assistant Dean of Students, where he modernized curriculum, expanded hands-on diagnostic training, and strengthened laboratory education infrastructure in resource-limited settings. His work contributed to building a more skilled medical diagnostics workforce and improving pathways for laboratory science education.
Awarded a prestigious national merit scholarship, Dr. Mutahar continued his graduate and doctoral training in India, completing his M.S. and Ph.D. in Biotechnology with a focus on triple-negative breast cancer. During his doctoral work, he developed 3D tumor spheroid models and combinatorial therapeutic strategies, demonstrating synergy between anti-angiogenic agents and chemotherapy in TNBC. He further advanced this research by creating an orthotopic murine model to investigate metastatic progression and demonstrated that knockdown of the MTA1 gene in mesenchymal stem cells (MSCs) significantly suppressed TNBC invasion, angiogenesis, and metastatic spread, introducing a promising stromal-targeted therapeutic concept for aggressive breast cancer. This work earned recognition through travel grants, conference presentations, and a Best Poster Award. His scientific adaptability was further demonstrated during the COVID-19 pandemic, when he uncovered a novel interaction between SARS-CoV-2 Spike RBD and VEGF signaling.
At Stanford, his work emphases on FLASH radiotherapy, an ultrahigh-dose-rate modality with the potential to widen the therapeutic window by minimizing normal-tissue toxicity while maintaining tumor control. Working within Dr. Dirbas’s translational breast oncology program, Dr. Mutahar employs patient-derived xenografts, orthotopic murine models, spatial transcriptomics, single-cell RNA sequencing, and immune profiling to dissect the biological mechanisms governing treatment response. His research integrates multi-omics analysis to map early and late radiotherapy injury pathways—including senescence, apoptosis and fibrosis. His goal is to develop mechanism-driven radio-immunotherapy strategies and durable FLASH-RT combination regimens that can be translated into clinical trials for breast cancer, improving therapeutic durability, minimizing toxicity, and ultimately enhancing patient outcomes.
Dr. Mutahar’s long-term vision is to establish an independent laboratory at the intersection of radiobiology, immuno-oncology, and translational therapeutics. Guided by Dr. Dirbas’s mentorship and shaped by multidisciplinary experience across three continents, he aims to develop biologically informed treatment strategies that eradicate tumors while preserving normal tissue and immune integrity—ultimately improving quality of life and survival for women with aggressive breast cancers. -
Aussama Nassar, MD, MSc,FACS, FRCSC
Clinical Associate Professor, Surgery - General Surgery
BioDr. Nassar is board-certified in both General Surgery and Surgical Critical Care in the United States and Canada, underscoring his exceptional expertise in these fields. He holds a Master of Science in Health Science Education from McMaster University, Canada, further solidifying his strong academic foundation.
Currently, Dr. Nassar serves as the inaugural Director of the Emergency General Surgery Service and the Director of the Surgical Critical Care Fellowship Program at Stanford University. He is also the founder and director of the Surgery Resident Coaching Program. With over 12 years of clinical and academic experience at premier tertiary care referral centers across North America, Dr. Nassar brings unparalleled knowledge and leadership to his roles.
Dr. Nassar's clinical interests include trauma, acute care surgery, critical care, and a particular focus on abdominal wall reconstruction. As a dedicated clinician-educator, he is a certified simulation educator and serves as a course director for ATLS and ASSET programs. His research is centered on advancing surgical education, with an emphasis on fostering the development of non-technical skills in surgical training.
In addition to his educational initiatives, Dr. Nassar is actively engaged in developing innovative assessment tools for surgical trainees and addressing burnout among physicians and healthcare professionals. With a strong national and international presence, Dr. Nassar continues to shape the future of surgical education and healthcare delivery through his leadership, research, and advocacy. -
Kenneth Nieser
Postdoctoral Scholar, General Surgery
BioKen Nieser is a postdoctoral research fellow through the Big Data-Scientist Training Enhancement Program (BD-STEP) at the Palo Alto VA and in the Department of Surgery, Stanford School of Medicine. Ken received a BA in Physics and Mathematics from Swarthmore College and a PhD in Epidemiology with a minor in Statistics from the University of Wisconsin-Madison. During his PhD, Ken developed and applied statistical methods for improving algorithmic fairness of data analyses used to inform screening and treatment of mental illnesses. These projects included development of an approach for detecting sample subsets with differential psychological symptom patterns and a sample representation reweighting method for improving the precision of subgroup-specific treatment effect estimation.
Ken’s current research interests are in health care inequities, quality measurement, and algorithmic fairness. During his fellowship, Ken will be working on investigating the statistical reliability of quality measures and decomposing health care disparities to provide practical information for resolving inequities, with applications in mental health care and surgical care. -
Jeffrey Norton, MD
Robert L. and Mary Ellenburg Professor of Surgery, Emeritus
Current Research and Scholarly InterestsInterleukin-12 is a Th1 cytokine. It is important in the cell mediated immune response. We are investigating its role as an anti-tumor cytokine to augment the immune response against cancer. We are planning a human trial.
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Hang T Pham
Research Specialist, Surgery - General Surgery
Current Role at StanfordStanford School of Medicine: Senior Research Scientist
Stanford Prevention Policy Modeling Lab: Affiliated Member (https://ppml.stanford.edu/people/hang-pham) -
George A. Poultsides, MD, MS
Stanford Department of Surgery Professor
Current Research and Scholarly InterestsClinical trials of experimental diagnostics and therapeutics; outcomes analysis following combined modality treatment of hepatic, pancreatic, and gastrointestinal malignancies.
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Carla Pugh, MD, PhD
Thomas Krummel Professor
Current Research and Scholarly InterestsThe Technology Enabled Clinical Improvement (T.E.C.I.) Center is a multidisciplinary team of researchers dedicated to the design and implementation of advanced engineering technologies that facilitate data acquisition relating to clinical performance.
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Benjamin Micah Raber
Clinical Assistant Professor, Surgery - General Surgery
BioDr. Benjamin Raber is a board-certified, fellowship-trained surgical oncologist at Stanford Health Care. He is also a clinical assistant professor in the Department of Surgery, Division of General Surgery at Stanford University School of Medicine.
Dr. Raber specializes in surgical treatments for benign and cancerous breast diseases. He performs a wide range of procedures, including lumpectomy, nipple-sparing mastectomy, and preventive mastectomy. Dr. Raber uses the latest and most effective surgical approaches, including wire-free, breast-conserving surgery for lumpectomies and hidden scar surgery (to hide incisions). He is committed to compassionate, patient-centered care that involves close collaboration with his colleagues in medical and radiation oncology, radiology, and plastic surgery.
Dr. Raber is actively involved in community outreach and breast cancer education. He has led regional initiatives to promote awareness, expand access to breast cancer screenings, and improve early detection.
Dr. Raber’s research focuses on improving surgical treatments for breast cancer, including better ways to treat cancer that has spread to nearby lymph nodes. He has also explored using ultrasound imaging to help surgeons locate and remove cancerous tissue more precisely during breast-conserving surgery. His research has been published in prominent peer-reviewed journals, including Annals of Surgical Oncology, Magnetic Resonance Imaging Clinics of North America, and The American Journal of Surgery.
Dr. Raber is a fellow of the American College of Surgeons (ACS) and a member of the American Society of Breast Surgeons (ASBrS). -
Dan Riskin
Clinical Professor (Affiliated), Surgery - General Surgery
Staff, Surgery - General SurgeryBioDr. Riskin is a Clinical Professor of Surgery at Stanford University and a physician–entrepreneur focused on the application of artificial intelligence in healthcare. His work spans clinical practice, company building, and public policy, with a focus on using clinical data to improve care.
He has founded and led multiple healthcare technology companies applying artificial intelligence to clinical data, with products used by leading health systems, pharmaceutical companies, and insurers and influencing the care of millions of patients. He is the CEO of Verantos, a healthcare AI company focused on improving the reliability of real-world clinical data used in research and care.
Dr. Riskin has contributed to health policy in the United States and internationally, including Congressional testimony related to the 21st Century Cures Act and service on the U.S. Health Information Technology Advisory Committee (HITAC). His work has been featured in The Wall Street Journal and Forbes.
Dr. Riskin received his MD from Boston University, completed residency in surgery at UCLA, and fellowship training in critical care and acute care surgery at Stanford University. He is board-certified in surgery, critical care, palliative care, and clinical informatics. He also holds an MBA from the Massachusetts Institute of Technology and was a Stanford Biodesign Innovation Fellow. -
Perisa Ruhi-Williams, MD
Clinical Assistant Professor (Affiliated), Surgery - General Surgery
Staff, Surgery - General SurgeryBioDr. Perisa Ruhi-Williams is a board-certified General Surgeon practicing at the VA Palo Alto Health Care System. Her clinical practice is centered on utilizing robotic-assisted techniques for metabolic/bariatric surgery and hernia and abdominal wall reconstruction.
She graduated as an Echols Scholar with a Bachelor of Science in Biology from the University of Virginia. She earned her MD from the Virginia Tech Carilion School of Medicine and completed her General Surgery residency at the University of California, Irvine. While in residency, she served as the Chief Resident in Quality and Patient Safety at the VA Long Beach Medical Center. She subsequently completed an advanced fellowship in Minimally Invasive Surgery, Bariatrics, and Foregut Surgery at Stanford Health Care.
Dr. Ruhi-Williams is passionate about advancing surgical education and the wellness of surgical trainees. In addition to her clinical roles, she serves as the Site Director for the Surgery Core Clerkship at VA Palo Alto and Assistant Site Director for the General Surgery Residency Program at VA Palo Alto. -
Brian Ruhle, MD, MS
Clinical Assistant Professor, Surgery - General Surgery
BioDr. Brian Ruhle is a board-certified surgeon with dual-fellowship training in minimally invasive bariatric (weight loss) surgery and endocrine surgery. He is also a clinical assistant professor in the Department of Surgery, Division of General Surgery at Stanford University School of Medicine.
Dr. Ruhle specializes in bariatric surgery, foregut (upper digestive tract) surgery, adrenal surgery, and abdominal wall reconstruction. He uses leading-edge laparoscopic and robotic surgical techniques to help patients achieve sustainable weight loss and improve obesity-related health conditions. His expertise in advanced minimally invasive procedures offers patients significant benefits, including faster recoveries, reduced pain, and shorter hospital stays.
Dr. Ruhle’s research interests span a wide range of topics in metabolic and bariatric surgery. His studies have explored combination therapies for managing obesity, improvements in screening and treating endocrine disorders, and optimizing outcomes in thyroid and parathyroid surgeries. He has published his findings in many peer-reviewed journals, including Surgery, Journal of Gastrointestinal Surgery, and Journal of the American College of Surgeons.
Dr. Ruhle has presented at prominent national conferences, including the annual meetings of the American Association of Endocrine Surgeons and the American College of Surgeons Clinical Congress. His presentations have discussed using GLP-1 receptor agonists (weight loss medications that help regulate blood sugar and reduce appetite) before and after bariatric surgery. He has also addressed improving screening protocols for hyperaldosteronism (high blood pressure caused by excess production of the hormone aldosterone by the adrenal gland).
Dr. Ruhle is a member of the American Association of Endocrine Surgeons, the American Society for Metabolic and Bariatric Surgery, and the Society of American Gastrointestinal and Endoscopic Surgeons. -
Alejandra Ruiz
Postdoctoral Scholar, General Surgery
BioDr. Alejandra Ruiz is a physician-scientist working at the intersection of clinical medicine, health services research, and community-engaged intervention design. Based on her clinical experience in high-complexity settings, she works to optimize integrative care models that address both physical and mental health needs.
She is currently a postdoctoral researcher in the Departments of Emergency Medicine and General Surgery, where she examines structural barriers to care among underserved populations and develops pathways to improve access and care delivery. Her work is grounded in community-based participatory research, through which she designs, implements, and evaluates culturally responsive interventions. Dr. Ruiz is committed to advancing equitable, sustainable models of care that improve access, engagement, and patient outcomes.
