Bio

Honors & Awards


  • Top Poster Award, Stanford Medical Student Research Symposium (Spring 2019)
  • Phi Beta Kappa, Junior Year Inductee, Emory University (2013)
  • Top Poster Award, Summer Undergraduate Research Symposium, Emory University (Summer 2012)
  • Dean's List, Emory University (2010-2014)

Professional Affiliations and Activities


  • Member, Congress of Neurological Surgeons (2018 - Present)
  • Member, American Association of Neurological Surgeons (2016 - Present)

Membership Organizations


  • AANS Student Chapter, Stanford School of Medicine, Board Member
  • Pacific Free Clinic, Immersion in Community Medicine, Co-Director

Education & Certifications


  • Bachelor of Science, Emory University, Biology (2014)

Clerkships


  • 2019 Spring - NSUR 318A Subinternship in Neurosurgery
  • 2018 Autumn - RAD 306A Neuroradiology Clerkship
  • 2017 Autumn - PEDS 300A Pediatrics Core Clerkship
  • 2017 Autumn - PSYC 300A Psychiatry Core Clerkship
  • 2017 Spring - MED 300A Internal Medicine Core Clerkship
  • 2017 Summer - NENS 301A Neurology Core Clerkship
  • 2017 Summer - SURG 300A Surgery Core Clerkship

Stanford Advisors


Service, Volunteer and Community Work


  • Stanford Transformative Experience in Medicine (SSTEM), Stanford University

    Mentor in outreach program designed to reach out to high school students from underrepresented or disadvantaged backgrounds, giving students an opportunity to explore the medical profession, provide exposure to the medical field that would have otherwise been difficult to obtain.

    Location

    Stanford, CA

  • Pacific Free Clinic, Stanford University

    Co-Director of Immersion in Community Medicine (ICM) program, mission of educating local high school students in the San Jose area through medicine and volunteerism.

    Location

    San Jose, CA

Research & Scholarship

Research Projects


  • Identification of In Vivo Paracrine Factors Secreted by hNSCs in the Ischemic Rat Brain (MedScholars Project)
  • Deep Convolutional Neural Networks for Automated Intracranial Aneurysm Detection and Endovascular Treatment Outcome Prediction (MedScholars Project)

    Location

    Stanford, CA

    Organization

    Stanford University

Publications

All Publications


  • Molecular correlates of cerebellar mutism syndrome in medulloblastoma. Neuro-oncology Jabarkheel, R., Amayiri, N., Yecies, D., Huang, Y., Toescu, S., Nobre, L., Mabbott, D. J., Sudhakar, S. V., Malik, P., Laughlin, S., Swaidan, M., Al Hussaini, M., Musharbash, A., Chacko, G., Mathew, L. G., Fisher, P. G., Hargrave, D., Bartels, U., Tabori, U., Pfister, S. M., Aquilina, K., Taylor, M. D., Grant, G. A., Bouffet, E., Mankad, K., Yeom, K. W., Ramaswamy, V. 2019

    Abstract

    BACKGROUND: Cerebellar Mutism Syndrome (CMS) is a common complication following resection of posterior fossa tumors, most commonly after surgery for medulloblastoma. Medulloblastoma subgroups have historically been treated as a single entity when assessing CMS risk; however, recent studies highlighting their clinical heterogeneity suggest the need for subgroup-specific analysis. Here, we examine a large international multicenter cohort of molecularly characterized medulloblastoma patients to assess predictors of CMS.METHODS: We assembled a cohort of 370 molecularly characterized medulloblastoma subjects with available neuroimaging from five sites globally including Great Ormond Street Hospital, Christian Medical College and Hospital, Hospital for Sick Children, King Hussein Cancer Center, and Lucile Packard Children's Hospital. Age at diagnosis, sex, tumour volume, and CMS development were assessed in addition to molecular subgroup.RESULTS: Overall, 23.8% of patients developed CMS. CMS patients were younger (mean difference -2.05 years ± 0.50, P=0.0218) and had larger tumours (mean difference 10.25 cm3 ± 4.60, P=0.0010) that were more often midline (OR=5.72, P<0.0001). In a multivariable analysis adjusting for age, sex, midline location, and tumour volume, WNT (Wingless) (adjusted OR=4.91, p=0.0063), Group 3 (adjusted OR=5.56, p=0.0022) and Group 4 (adjusted OR=8.57 p=9.1x10-5) tumours were found to be independently associated with higher risk of CMS compared with SHH (Sonic Hedgehog) tumours.CONCLUSIONS: Medulloblastoma subgroup is a very strong predictor of CMS development, independent of tumour volume and midline location. These findings have significant implications for management of both the tumour and CMS.

    View details for DOI 10.1093/neuonc/noz158

    View details for PubMedID 31504816

  • Posterior fossa syndrome and increased mean diffusivity in the olivary bodies. Journal of neurosurgery. Pediatrics Yecies, D., Jabarkheel, R., Han, M., Kim, Y., Bruckert, L., Shpanskaya, K., Perez, A., Edwards, M. S., Grant, G. A., Yeom, K. W. 2019: 1–6

    Abstract

    OBJECTIVE: Posterior fossa syndrome (PFS) is a common postoperative complication following resection of posterior fossa tumors in children. It typically presents 1 to 2 days after surgery with mutism, ataxia, emotional lability, and other behavioral symptoms. Recent structural MRI studies have found an association between PFS and hypertrophic olivary degeneration, which is detectable as T2 hyperintensity in the inferior olivary nuclei (IONs) months after surgery. In this study, the authors investigated whether immediate postoperative diffusion tensor imaging (DTI) of the ION can serve as an early imaging marker of PFS.METHODS: The authors retrospectively reviewed pediatric brain tumor patients treated at their institution, Lucile Packard Children's Hospital at Stanford, from 2004 to 2016. They compared the immediate postoperative DTI studies obtained in 6 medulloblastoma patients who developed PFS to those of 6 age-matched controls.RESULTS: Patients with PFS had statistically significant increased mean diffusivity (MD) in the left ION (1085.17 ± 215.51 vs 860.17 ± 102.64, p = 0.044) and variably increased MD in the right ION (923.17 ± 119.2 vs 873.67 ± 60.16, p = 0.385) compared with age-matched controls. Patients with PFS had downward trending fractional anisotropy (FA) in both the left (0.28 ± 0.06 vs 0.23 ± 0.03, p = 0.085) and right (0.29 ± 0.06 vs 0.25 ± 0.02, p = 0.164) IONs compared with age-matched controls, although neither of these values reached statistical significance.CONCLUSIONS: Increased MD in the ION is associated with development of PFS. ION MD changes may represent an early imaging marker of PFS.

    View details for DOI 10.3171/2019.5.PEDS1964

    View details for PubMedID 31349230

  • Arterial spin labeling perfusion changes of the frontal lobes in children with posterior fossa syndrome. Journal of neurosurgery. Pediatrics Yecies, D., Shpanskaya, K., Jabarkheel, R., Maleki, M., Bruckert, L., Cheshier, S. H., Hong, D., Edwards, M. S., Grant, G. A., Yeom, K. W. 2019: 1–7

    Abstract

    Posterior fossa syndrome (PFS) is a common complication following the resection of posterior fossa tumors in children. The pathophysiology of PFS remains incompletely elucidated; however, the wide-ranging symptoms of PFS suggest the possibility of widespread cortical dysfunction. In this study, the authors utilized arterial spin labeling (ASL), an MR perfusion modality that provides quantitative measurements of cerebral blood flow without the use of intravenous contrast, to assess cortical blood flow in patients with PFS.A database of medulloblastoma treated at the authors' institution from 2004 to 2016 was retrospectively reviewed, and 14 patients with PFS were identified. Immediate postoperative ASL for patients with PFS and medulloblastoma patients who did not develop PFS were compared. Additionally, in patients with PFS, ASL following the return of speech was compared with immediate postoperative ASL.On immediate postoperative ASL, patients who subsequently developed PFS had statistically significant decreases in right frontal lobe perfusion and a trend toward decreased perfusion in the left frontal lobe compared with controls. Patients with PFS had statistically significant increases in bilateral frontal lobe perfusion after the resolution of symptoms compared with their immediate postoperative imaging findings.ASL perfusion imaging identifies decreased frontal lobe blood flow as a strong physiological correlate of PFS that is consistent with the symptomatology of PFS. This is the first study to demonstrate that decreases in frontal lobe perfusion are present in the immediate postoperative period and resolve with the resolution of symptoms, suggesting a physiological explanation for the transient symptoms of PFS.

    View details for DOI 10.3171/2019.5.PEDS18452

    View details for PubMedID 31374541

  • Deep Learning-Assisted Diagnosis of Cerebral Aneurysms Using the HeadXNet Model. JAMA network open Park, A., Chute, C., Rajpurkar, P., Lou, J., Ball, R. L., Shpanskaya, K., Jabarkheel, R., Kim, L. H., McKenna, E., Tseng, J., Ni, J., Wishah, F., Wittber, F., Hong, D. S., Wilson, T. J., Halabi, S., Basu, S., Patel, B. N., Lungren, M. P., Ng, A. Y., Yeom, K. W. 2019; 2 (6): e195600

    Abstract

    Deep learning has the potential to augment clinician performance in medical imaging interpretation and reduce time to diagnosis through automated segmentation. Few studies to date have explored this topic.To develop and apply a neural network segmentation model (the HeadXNet model) capable of generating precise voxel-by-voxel predictions of intracranial aneurysms on head computed tomographic angiography (CTA) imaging to augment clinicians' intracranial aneurysm diagnostic performance.In this diagnostic study, a 3-dimensional convolutional neural network architecture was developed using a training set of 611 head CTA examinations to generate aneurysm segmentations. Segmentation outputs from this support model on a test set of 115 examinations were provided to clinicians. Between August 13, 2018, and October 4, 2018, 8 clinicians diagnosed the presence of aneurysm on the test set, both with and without model augmentation, in a crossover design using randomized order and a 14-day washout period. Head and neck examinations performed between January 3, 2003, and May 31, 2017, at a single academic medical center were used to train, validate, and test the model. Examinations positive for aneurysm had at least 1 clinically significant, nonruptured intracranial aneurysm. Examinations with hemorrhage, ruptured aneurysm, posttraumatic or infectious pseudoaneurysm, arteriovenous malformation, surgical clips, coils, catheters, or other surgical hardware were excluded. All other CTA examinations were considered controls.Sensitivity, specificity, accuracy, time, and interrater agreement were measured. Metrics for clinician performance with and without model augmentation were compared.The data set contained 818 examinations from 662 unique patients with 328 CTA examinations (40.1%) containing at least 1 intracranial aneurysm and 490 examinations (59.9%) without intracranial aneurysms. The 8 clinicians reading the test set ranged in experience from 2 to 12 years. Augmenting clinicians with artificial intelligence-produced segmentation predictions resulted in clinicians achieving statistically significant improvements in sensitivity, accuracy, and interrater agreement when compared with no augmentation. The clinicians' mean sensitivity increased by 0.059 (95% CI, 0.028-0.091; adjusted P = .01), mean accuracy increased by 0.038 (95% CI, 0.014-0.062; adjusted P = .02), and mean interrater agreement (Fleiss κ) increased by 0.060, from 0.799 to 0.859 (adjusted P = .05). There was no statistically significant change in mean specificity (0.016; 95% CI, -0.010 to 0.041; adjusted P = .16) and time to diagnosis (5.71 seconds; 95% CI, 7.22-18.63 seconds; adjusted P = .19).The deep learning model developed successfully detected clinically significant intracranial aneurysms on CTA. This suggests that integration of an artificial intelligence-assisted diagnostic model may augment clinician performance with dependable and accurate predictions and thereby optimize patient care.

    View details for DOI 10.1001/jamanetworkopen.2019.5600

    View details for PubMedID 31173130

  • Pediatric parapharyngeal infection resulting in cervical instability and occipital-cervical fusion-case report and review of the literature CHILDS NERVOUS SYSTEM Chen, Y., Sole, J., Jabarkheel, R., Edwards, M., Cheshier, S. 2019; 35 (5): 893–95
  • Posttraumatic Syringomyelia Complications in Neurosurgery 2019 Jabarkheel, R., Gibani, S., Chen, Y., Ratliff, J. K. Elsevier. 2019: 372–376
  • Trans-Oral Endoscopic Resection of High Cervical Osteophytes with Long-term Symptom Resolution: Case Series, Imaging, and Literature Review. World neurosurgery Jabarkheel, R., Chen, Y., Xu, L., Yan, C. H., Patel, Z. M., Desai, A. M. 2018

    Abstract

    BACKGROUND: Anterior cervical osteophytes (ACOs) are a common radiological finding in the elderly; rarely, they can cause dysphagia, dysphonia, and dyspnea. Symptomatic ACOs are most commonly found between C4-C7 and much less commonly at higher cervical levels. Here, we present a case series, with an example case of a 57-year-old woman with high cervical osteophytes at C1-C2 causing globus sensation, dysphagia, and dysphonia. Additionally, we provide a literature review regarding the etiology, diagnosis, and treatment of ACOs with a focus on management of high ACOs.CASE DESCRIPTION: A 57 year-old smoker with a history of chronic neck pain and previous cervical spinal instrumentation presented with several months of globus sensation, dysphagia, and dysphonia. Imaging revealed two large anterior osteophytes at C1-C2. She underwent endoscopic trans-oral osteophytectomy with resolution of symptoms. Five other patients are also presented who underwent similar procedures.CONCLUSIONS: ACOs are a potential cause of dysphagia, and their diagnosis is best made with CT imaging and oropharyngeal swallow study. Although high ACOs at C1-C2 are a rare finding, here we show with an exemplary case and small case series that they can be effectively treated with trans-oral endoscopic osteophytectomy.

    View details for PubMedID 30193964

  • Stereotactic radiosurgery for central nervous system hemangioblastoma: systematic review and meta-analysis JOURNAL OF NEURO-ONCOLOGY Pan, J., Jabarkheel, R., Huang, Y., Ho, A., Chang, S. D. 2018; 137 (1): 11–22

    Abstract

    Hemangioblastomas are rare, benign, vascular tumors of the central nervous system (CNS), often associated with von-hippel lindau (VHL) disease. Current therapeutic options include microsurgical resection or stereotactic radiosurgery (SRS). With no randomized controlled studies and minimal data beyond single-institution reviews, the optimal management approach for patients with CNS hemangioblastomas is unclear. We completed a Pubmed/SCOPUS literature search from January 1990 to January 2017 for eligible studies on SRS for CNS hemangioblastomas. Relevant articles were identified and reviewed in accordance to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. 26 studies met eligibility criteria for qualitative synthesis, representing 596 subjects and 1535 tumors. The Gamma Knife was the most published SRS method for CNS hemangioblastomas. After critical study appraisal for intra-study bias, 14 studies were used for quantitative meta-analysis of 5-year progression free survival (PFS). The pooled 5-year PFS across all eligible studies was 88.4%. No difference was observed between spine versus intracranial studies. Individual patient data (IPD) was extracted from 14 studies, representing 322 tumors. Univariate analysis of IPD revealed that VHL patients were younger, and had smaller tumors compared to those with sporadic disease. Adverse events were associated with increasing marginal dose, independent of tumor volume. VHL status, sex, radiosurgical method, tumor location, and tumor volume were not found to be significantly associated with tumor progression. Multiple studies show excellent tumor control at 5-year follow up, however, the long-term efficacy of SRS for CNS hemangioblastomas still needs to be investigated, and the studies exploring the role of SRS for early treatment of asymptomatic lesions is wanting.

    View details for PubMedID 29204841

  • Minimally Invasive Lumbar Pedicle Screw Fixation Using Cortical Bone Trajectory: Functional Outcomes. Cureus Chen, Y., Deb, S., Jabarkheel, R., Pham, L., Patel, M., Singh, H. 2018; 10 (10): e3462

    Abstract

    Background Pedicle screw fixation is currently the mainstay technique for lumbar spinal fusion; however, more minimally invasive techniques are available such as cortical screw fixation. Numerous studies have proven biomechanical equivalence or superiority for cortical screws but few studies have examined clinical outcomes in patients. Our study aims to examine functional outcomes, as well as fusion rates, in patients who underwent pedicle screw fixation using a cortical trajectory. Methods We retrospectively reviewed prospectively collected functional outcomes data on 10 patients with a degenerative lumbar disease who underwent cortical screw placement by the senior author. Oswestry Disability Index (ODI) and Roland Morris (RM) scoring were calculated preoperatively, at six to 12 weeks and at six to eight months. The Kruskal-Wallis test and Dunn's multiple comparison were used to analyze differences in scores over time. Results We found that over time, cortical screw fixation resulted in a mean decrease of 27 from the baseline ODI at six to eight months (p = 0.014). Additionally, six out of seven (86%) patients who had at least 12 months of radiographic follow-up showed fusion. Conclusions Cortical screw fixation showed a decrease of 27 from the baseline ODI at six to eight months, which is comparable to changes from the baseline ODI reported in three, recent, large clinical trials examining functional outcomes following traditional pedicle screw fixation.

    View details for PubMedID 30564541