Bio


Ryan Brewster is a third-year MD candidate at the Stanford University School of Medicine. He is pursuing a career in pediatric cardiology or hematology/oncology and is passionate about reducing health inequities through technology and entrepreneurship. His current research in the Bhatt Lab examines the relationship between the gut microbiome and cardiometabolic disease in South Africa. Additionally, he is a Schweitzer Fellow with the Stanford Pediatrics Advocacy Program, and is involved in several early-stage medical technology projects in pediatric cardiology, neonatology, digital pathology, and women's health. Ryan earned his B.A. in Molecular Biology/Biochemistry and Spanish from Middlebury College.

Honors & Awards


  • MacKenzie Foundation Scholarship, The MacKenzie Foundation (2019)
  • MedScholars Grant Recipient, Stanford University School of Medicine (2017-2019)
  • Kaiser Permanente Medical Student Scholarship, Kaiser Permanente Northern California (2019)
  • Biodesign NEXT Fellow, Byers Center for Biodesign (2017)
  • Mary Duke Biddle Clinical Scholar, Stanford Center for Innovation in Global Health (2019)
  • David A. Zlotnick Scholarship, Stanford Center for Innovation in Global Health (2019)
  • Schweitzer Fellow, Albert Schweitzer Fellowship (2018-2019)

Education & Certifications


  • Certificate, Stanford Graduate School of Business Ignite (2019)
  • Bachelor of Arts, Middlebury College, Molecular Bio & Biochemistry (2014)

All Publications


  • Socioeconomic Predictors of Surgical Resection and Survival for Patients With Osseous Spinal Neoplasms CLINICAL SPINE SURGERY Deb, S., Brewster, R., Pendharkar, A., Veeravagu, A., Ratliff, J., Desai, A. 2019; 32 (3): 125–31
  • Frameless Robot-Assisted Deep Brain Stimulation Surgery: An Initial Experience. Operative neurosurgery (Hagerstown, Md.) Ho, A. L., Pendharkar, A. V., Brewster, R., Martinez, D. L., Jaffe, R. A., Xu, L. W., Miller, K. J., Halpern, C. H. 2019

    Abstract

    BACKGROUND: Modern robotic-assist surgical systems have revolutionized stereotaxy for a variety of procedures by increasing operative efficiency while preserving and even improving accuracy and safety. However, experience with robotic systems in deep brain stimulation (DBS) surgery is scarce.OBJECTIVE: To present an initial series of DBS surgery performed utilizing a frameless robotic solution for image-guided stereotaxy, and report on operative efficiency, stereotactic accuracy, and complications.METHODS: This study included the initial 20 consecutive patients undergoing bilateral robot-assisted DBS. The prior 20 nonrobotic, frameless cohort of DBS cases was sampled as a baseline historic control. For both cohorts, patient demographic and clinical data were collected including postoperative complications. Intraoperative duration and number of Microelectrode recording (MER) and final lead passes were recorded. For the robot-assisted cohort, 2D radial errors were calculated.RESULTS: Mean case times (total operating room, anesthesia, and operative times) were all significantly decreased in the robot-assisted cohort (all P-values<.02) compared to frameless DBS. When looking at trends in case times, operative efficiency improved over time in the robot-assisted cohort across all time assessment points. Mean radial error in the robot-assisted cohort was 1.40±0.11mm, and mean depth error was 1.05±0.18mm. There was a significant decrease in the average number of MER passes in the robot-assisted cohort (1.05) compared to the nonrobotic cohort (1.45, P<.001).CONCLUSION: This is the first report of application of frameless robotic-assistance with the Mazor Renaissance platform (Mazor Robotics Ltd, Caesarea, Israel) for DBS surgery, and our findings reveal that an initial experience is safe and can have a positive impact on operative efficiency, accuracy, and safety.

    View details for PubMedID 30629245

  • Surveying Gut Microbiome Research in Africans: Toward Improved Diversity and Representation. Trends in microbiology Brewster, R., Tamburini, F. B., Asiimwe, E., Oduaran, O., Hazelhurst, S., Bhatt, A. S. 2019

    Abstract

    Descriptive and translational investigations into the human gut microbiome (GM) are rapidly expanding; however, studies are largely restricted to industrialized populations in the USA and Europe. Little is known about microbial variability and its implications for health and disease in other parts of the world. Populations in Africa are particularly underrepresented. What limited research has been performed has focused on a few subject domains, including the impact of long-term lifestyle and dietary factors on GM ecology, its maturation during infancy, and the interrelationships between the microbiome, infectious disease, and undernutrition. Recently, international consortia have laid the groundwork for large-scale genomics and microbiome studies on the continent, with a particular interest in the epidemiologic transition to noncommunicable disease. Here, we survey the current landscape of GM scholarship in Africa and propose actionable recommendations to improve research capacity and output.

    View details for DOI 10.1016/j.tim.2019.05.006

    View details for PubMedID 31178123

  • The Search for Meaning ACADEMIC MEDICINE Brewster, R., Vyas, D. 2018; 93 (6): 823
  • Endoscope-assisted repair of CSF otorrhea and temporal lobe encephaloceles via keyhole craniotomy. Journal of neurosurgery Roehm, P. C., Tint, D., Chan, N., Brewster, R., Sukul, V., Erkmen, K. 2018; 128 (6): 1880–84

    Abstract

    OBJECTIVE Temporal lobe encephaloceles and cerebrospinal fluid otorrhea from temporal bone defects that involve the tegmen tympani and mastoideum are generally repaired using middle fossa craniotomy, mastoidectomy, or combined approaches. Standard middle fossa craniotomy exposes patients to dural retraction, which can lead to postoperative neurological complications. Endoscopic and minimally invasive techniques have been used in other surgeries to minimize brain retraction, and so these methods were applied to repair the lateral skull base. The goal of this study was to determine if the use of endoscopic visualization through a middle fossa keyhole craniotomy could effectively repair tegmen defects. METHODS The authors conducted a retrospective review of 6 cases of endoscope-assisted middle fossa repairs of tegmen dehiscences at a tertiary care medical center within an 18-month period. RESULTS All cases were successfully treated using a keyhole craniotomy with endoscopic visualization and minimal retraction. Surgical times did not increase. There were no major postoperative complications, recurrences of encephaloceles, or cerebrospinal fluid otorrhea in these patients. CONCLUSIONS Endoscopic visualization allows for smaller incisions and craniotomies and less risk of brain retraction injury without compromising repair integrity during temporal encephalocele and tegmen repairs.

    View details for DOI 10.3171/2017.1.JNS161947

    View details for PubMedID 28799867

  • Meningioma transcription factors link cell lineage with systemic metabolic cues. Neuro-oncology Du, Z., Brewster, R., Merrill, P. H., Chmielecki, J., Francis, J., Aizer, A., Abedalthagafi, M., Sholl, L. M., Geffers, L., Alexander, B., Santagata, S. 2018; 20 (10): 1331–43

    Abstract

    Tumor cells recapitulate cell-lineage transcriptional programs that are characteristic of normal tissues from which they arise. It is unclear why such lineage programs are fatefully maintained in tumors and if they contribute to cell proliferation and viability.Here, we used the most common brain tumor, meningioma, which is strongly associated with female sex and high body mass index (BMI), as a model system to address these questions. We screened expression profiling data to identify the transcription factor (TF) genes which are highly enriched in meningioma, and characterized the expression pattern of those TFs and downstream genes in clinical meningioma samples as well as normal brain tissues. Meningioma patient-derived cell lines (PDCLs) were used for further validation and characterization.We identified 8 TFs highly enriched in meningioma. Expression of these TFs, which included sine oculis homeobox 1 (SIX1), readily distinguished meningiomas from other primary brain tumors and was maintained in PDCLs and even in pulmonary meningothelial nodules. In meningioma PDCLs, SIX1 and its coactivator eyes absent 2 (EYA2) supported the expression of the leptin receptor (LEPR), the cell-surface receptor for leptin (LEP), the adipose-specific hormone that is high in women and in individuals with high BMI. Notably, these transcriptional regulatory factors, LEPR and LEP, both contributed to support meningioma PDCLs proliferation and survival, elucidating a survival dependency on both a core transcriptional program and a metabolic cell-surface receptor.These findings provide one rationale for why lineage TF expression is maintained in meningioma and for the epidemiological association of female sex and obesity with meningioma risk.

    View details for DOI 10.1093/neuonc/noy057

    View details for PubMedID 29660031

    View details for PubMedCentralID PMC6120365

  • Germline and somatic BAP1 mutations in high-grade rhabdoid meningiomas. Neuro-oncology Shankar, G. M., Abedalthagafi, M., Vaubel, R. A., Merrill, P. H., Nayyar, N., Gill, C. M., Brewster, R., Bi, W. L., Agarwalla, P. K., Thorner, A. R., Reardon, D. A., Al-Mefty, O., Wen, P. Y., Alexander, B. M., van Hummelen, P., Batchelor, T. T., Ligon, K. L., Ligon, A. H., Meyerson, M., Dunn, I. F., Beroukhim, R., Louis, D. N., Perry, A., Carter, S. L., Giannini, C., Curry, W. T., Cahill, D. P., Barker, F. G., Brastianos, P. K., Santagata, S. 2017; 19 (4): 535–45

    Abstract

    Patients with meningiomas have widely divergent clinical courses. Some entirely recover following surgery alone, while others have relentless tumor recurrences. This clinical conundrum is exemplified by rhabdoid meningiomas, which are designated in the World Health Organization Classification of Tumours as high grade, despite only a subset following an aggressive clinical course. Patient management decisions are further exacerbated by high rates of interobserver variability, biased against missing possibly aggressive tumors. Objective molecular determinants are needed to guide classification and clinical decision making.To define genomic aberrations of rhabdoid meningiomas, we performed sequencing of cancer-related genes in 27 meningiomas from 18 patients with rhabdoid features and evaluated breast cancer [BRCA]1-associated protein 1 (BAP1) expression by immunohistochemistry in 336 meningiomas. We assessed outcomes, germline status, and family history in patients with BAP1-negative rhabdoid meningiomas.The tumor suppressor gene BAP1, a ubiquitin carboxy-terminal hydrolase, is inactivated in a subset of high-grade rhabdoid meningiomas. Patients with BAP1-negative rhabdoid meningiomas had reduced time to recurrence compared with patients with BAP1-retained rhabdoid meningiomas (Kaplan-Meier analysis, 26 mo vs 116 mo, P < .001; hazard ratio 12.89). A subset of patients with BAP1-deficient rhabdoid meningiomas harbored germline BAP1 mutations, indicating that rhabdoid meningiomas can be a harbinger of the BAP1 cancer predisposition syndrome.We define a subset of aggressive rhabdoid meningiomas that can be recognized using routine laboratory tests. We implicate ubiquitin deregulation in the pathogenesis of these high-grade malignancies. In addition, we show that familial and sporadic BAP1-mutated rhabdoid meningiomas are clinically aggressive, requiring intensive clinical management.

    View details for DOI 10.1093/neuonc/now235

    View details for PubMedID 28170043

    View details for PubMedCentralID PMC5464371

  • Superior semicircular canal dehiscence syndrome. Journal of neurosurgery Bi, W. L., Brewster, R., Poe, D., Vernick, D., Lee, D. J., Eduardo Corrales, C., Dunn, I. F. 2017; 127 (6): 1268–76

    Abstract

    Superior semicircular canal dehiscence (SSCD) syndrome is an increasingly recognized cause of vestibular and/or auditory symptoms in both adults and children. These symptoms are believed to result from the presence of a pathological mobile "third window" into the labyrinth due to deficiency in the osseous shell, leading to inadvertent hydroacoustic transmissions through the cochlea and labyrinth. The most common bony defect of the superior canal is found over the arcuate eminence, with rare cases involving the posteromedial limb of the superior canal associated with the superior petrosal sinus. Operative intervention is indicated for intractable or debilitating symptoms that persist despite conservative management and vestibular sedation. Surgical repair can be accomplished by reconstruction or plugging of the bony defect or reinforcement of the round window through a variety of operative approaches. The authors review the etiology, pathophysiology, presentation, diagnosis, surgical options, and outcomes in the treatment of this entity, with a focus on potential pitfalls that may be encountered during clinical management.

    View details for DOI 10.3171/2016.9.JNS16503

    View details for PubMedID 28084916

  • Oncogenic PI3K mutations are as common as AKT1 and SMO mutations in meningioma. Neuro-oncology Abedalthagafi, M., Bi, W. L., Aizer, A. A., Merrill, P. H., Brewster, R., Agarwalla, P. K., Listewnik, M. L., Dias-Santagata, D., Thorner, A. R., Van Hummelen, P., Brastianos, P. K., Reardon, D. A., Wen, P. Y., Al-Mefty, O., Ramkissoon, S. H., Folkerth, R. D., Ligon, K. L., Ligon, A. H., Alexander, B. M., Dunn, I. F., Beroukhim, R., Santagata, S. 2016; 18 (5): 649–55

    Abstract

    Meningiomas are the most common primary intracranial tumor in adults. Identification of SMO and AKT1 mutations in meningiomas has raised the possibility of targeted therapies for some patients. The frequency of such mutations in clinical cohorts and the presence of other actionable mutations in meningiomas are important to define.We used high-resolution array-comparative genomic hybridization to prospectively characterize copy-number changes in 150 meningiomas and then characterized these samples for mutations in AKT1, KLF4, NF2, PIK3CA, SMO, and TRAF7.Similar to prior reports, we identified AKT1 and SMO mutations in a subset of non-NF2-mutant meningiomas (ie, ∼9% and ∼6%, respectively). Notably, we detected oncogenic mutations in PIK3CA in ∼7% of non-NF2-mutant meningiomas. AKT1, SMO, and PIK3CA mutations were mutually exclusive. AKT1, KLF4, and PIK3CA mutations often co-occurred with mutations in TRAF7. PIK3CA-mutant meningiomas showed limited chromosomal instability and were enriched in the skull base.This work identifies PI3K signaling as an important target for precision medicine trials in meningioma patients.

    View details for DOI 10.1093/neuonc/nov316

    View details for PubMedID 26826201

    View details for PubMedCentralID PMC4827048

  • How a Lumbar Diskectomy Influenced Medical Malpractice and the Landscape of Health Care. World neurosurgery Yang, B. W., Bi, W. L., Smith, T. R., Brewster, R., Gormley, W. B., Dunn, I. F., Laws, E. R. 2016; 86: 88–92

    Abstract

    Jeff Chandler was one of Hollywood's top leading men in the 1950s and 1960s. In 1961, at the peak of his career, Chandler died of complications following an aortic-iliac injury during a routine lumbar diskectomy. The subsequent public outcry and malpractice suit resulted in an unprecedented settlement award.Chandler's lawsuit marked a pivotal time in the evolution of medical malpractice and monetary awards. Before 1960, malpractice legal claims were rare, with little impact on the practice of medicine. Chandler's award, however, dwarfed the average malpractice verdict for its time and would influence the relationship between medicine and the legal world. This case helped issue a radical increase in total expenditure on medical liability insurance, frequency of successful claims, average numbers of neurosurgical malpractice suits, and financial award sizes. The trend ensuing from this time has continued to the contemporary era. To link Chandler's case to the current malpractice climate, we highlight the relationship of the case with 3 factors comprising the legal argument for the perpetuation of medical malpractice: 1) contingency fees, 2) citizen juries, and 3) the nature of tort law.This case illustrates an inflection point in American medical malpractice expenditure increases beginning in the 1960s to a current estimated $55.6 billion. As we investigate ways to provide value in health care, it is important to consider the historical factors that have influenced the status quo when seeking strategies to reform the malpractice system on both sides of the value equation: quality and cost.

    View details for DOI 10.1016/j.wneu.2015.09.039

    View details for PubMedID 26409087

  • Genomic landscape of intracranial meningiomas. Journal of neurosurgery Bi, W. L., Abedalthagafi, M., Horowitz, P., Agarwalla, P. K., Mei, Y., Aizer, A. A., Brewster, R., Dunn, G. P., Al-Mefty, O., Alexander, B. M., Santagata, S., Beroukhim, R., Dunn, I. F. 2016; 125 (3): 525–35

    Abstract

    Meningiomas are the most common primary intracranial neoplasms in adults. Current histopathological grading schemes do not consistently predict their natural history. Classic cytogenetic studies have disclosed a progressive course of chromosomal aberrations, especially in high-grade meningiomas. Furthermore, the recent application of unbiased next-generation sequencing approaches has implicated several novel genes whose mutations underlie a substantial percentage of meningiomas. These insights may serve to craft a molecular taxonomy for meningiomas and highlight putative therapeutic targets in a new era of rational biology-informed precision medicine.

    View details for DOI 10.3171/2015.6.JNS15591

    View details for PubMedID 26771848

  • The neurosurgeon as baseball fan and inventor: Walter Dandy and the batter's helmet. Neurosurgical focus Brewster, R., Bi, W. L., Smith, T. R., Gormley, W. B., Dunn, I. F., Laws, E. R. 2015; 39 (1): E9

    Abstract

    Baseball maintains one of the highest impact injury rates in all athletics. A principal causative factor is the "beanball," referring to a pitch thrown directly at a batter's head. Frequent morbidities elicited demand for the development of protective gear development in the 20th century. In this setting, Dr. Walter Dandy was commissioned to design a "protective cap" in 1941. His invention became widely adopted by professional baseball and inspired subsequent generations of batting helmets. As a baseball aficionado since his youth, Walter Dandy identified a natural partnership between baseball and medical practice for the reduction of beaning-related brain injuries. This history further supports the unique position of neurosurgeons to leverage clinical insights, inform innovation, and expand service to society.

    View details for DOI 10.3171/2015.3.FOCUS1552

    View details for PubMedID 26126408

  • The Assassination of Abraham Lincoln and the Evolution of Neuro-Trauma Care: Would the 16th President Have Survived in the Modern Era? World neurosurgery Yan, S. C., Smith, T. R., Bi, W. L., Brewster, R., Gormley, W. B., Dunn, I. F., Laws, E. R. 2015; 84 (5): 1453–57

    Abstract

    Abraham Lincoln was the 16(th) President of the United States of America. On April 14, 1865, shortly after his re-election and the conclusion of the Civil War, Lincoln was shot and killed by John Wilkes Booth. Although numerous physicians tended to the President shortly after his injury, he passed away the next morning. Today, we recognize Lincoln as one of the greatest Presidents in American history. His assassination profoundly influenced the future of the United States, especially as the country was coming back together again following the Civil War. Testaments to his lasting legacy can be seen in many places, from the stone carving of him on Mount Rushmore to his image gracing the $5 bill. What if the President had survived his injury? Would he have had a different outcome utilizing current critical care treatment? Neurotrauma care in 1865 was not yet developed, and head wounds such as the one Lincoln sustained were almost always fatal. The medical attention he received is considered by historians and physicians today to be excellent for that time. We look at the evolution of neurotrauma care during the last 150 years in the US. Particular focus is paid to the advancement of care for penetrating brain injuries in modern trauma centers.

    View details for DOI 10.1016/j.wneu.2015.06.011

    View details for PubMedID 26092530

  • Evita's lobotomy. Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia Young, G. J., Bi, W. L., Smith, T. R., Brewster, R., Gormley, W. B., Dunn, I. F., Laws, E. R., Nijensohn, D. E. 2015; 22 (12): 1883–88

    Abstract

    For 60 years, the details about Eva Perón's illness and lobotomy at the end of her life have been obscured from the public. Here, we examine the sociopolitical factors that may have contributed to this secrecy. The first involves Eva Perón's political status and the personality cult surrounding her image, including partisan efforts to present her as a patron saint of Peronism. The second involves the social perceptions, which are often stigmatizing, regarding disease in political or public figures. Notably, neuropsychiatric illness and associated indications for treatment were viewed as oligarchic by the Perón regime, and admission to a lobotomy may have been perceived as anti-Peronist. A third factor involves the growing ignominy of prefrontal lobotomy as a surgical modality, which may have precluded operative exposés. A final factor may be that Eva Perón's lobotomy was in fact performed for behavior and personality modification, and not just for pain control. A brief history of lobotomy is presented, highlighting its adoption as a procedural panacea for psychiatric illnesses, relief of intractable pain from cancer, and management of belligerent behavior, and its subsequent fall from clinical favor. Although a shroud of secrecy still surrounds Eva Perón's prefrontal lobotomy, these factors provide a potential rationale for the circumstances, as well as foster a discussion of cultural elements that may still play a role in the public perception of psychosurgery today.

    View details for DOI 10.1016/j.jocn.2015.07.005

    View details for PubMedID 26463273