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Urology Fellowship

The purpose of the two-year Pediatric Urology Post Residency Training Program is to offer a broad, inclusive year of clinical training and a full year of dedicated research with the goal to produce the finest pediatric urologist possible.



The 1st year of the fellowship is fully dedicated to research under the direct supervision of Drs. Michael Hsieh, Dan Casella and Hans Pohl.  The overall goal of the research year is to expose fellows to basic science research and to build a basic understanding of the responsible conduct of research which will be broadly useful across future career paths.  Incoming fellows will review ongoing basic science projects with Drs. Hsieh and Casella and identify a project to focus on during their research year.  Fellows are welcome to participate in multiple projects, however given that there is only one year of dedicated time we feel that fellows will have the most opportunity for success with a narrow focus. 

Dr. Hsieh’s lab is currently focused on understanding the immunology of urinary tract infections and inflammation-induced bladder pathology.  He is also collaborating with Dr. Pohl to understand how the microbiome, the collection of microbes in and on our bodies (many of which are not cultivatable but detectable through molecular methods), affects risks of urinary tract infection.  Dr. Hsieh's immunological work is based on mouse models of urinary tract infection and overactive bladder.  His group is exploring how various arms of the immune system play a role in UTI.  The laboratory is also therapeutically exploiting host immunomodulatory proteins produced by urogenital parasites, the most evolutionarily advanced pathogens of the human urinary tract, for hemorrhagic cystitis and bladder hypersensitivity.

Dr. Casella’s lab is located on the main campus at Children's National Medical Center and has two ongoing projects, the first of which is working to understand the molecular mechanisms of cloacal membrane and genital tubercle development.  Utilizing the mouse embryo as a model, the aim of this project is to characterize a unique population of senescent cells in the developing genital tubercle.  Through the use of inducible genetic knockouts and molecular profiling techniques we hope to gain an understanding of the growth factors secreted by these “developmentally senescent” cells and their role in patterning the genital tubercle and urethra.

The second project in Dr. Casella’s lab is centered on the ability of low intensity focused ultrasound to stimulate targeted neurons.  Dr. Casella has recently demonstrated the ability of targeted ultrasound of the posterior tibial nerve to temporarily suppress bladder contraction in a rodent model.  He is currently working to refine his technique and generate the preliminary data required for a clinical trial in human subjects.  Ultimately Dr. Casella hopes to develop targeted low intensity ultrasound as a non-invasive and painless outpatient treatment for pediatric bladder and bowel dysfunction. 

Clinical Education

Clinical Education

The clinical year offers the fellow in-depth exposure in the clinical and surgical management of urologic problems in childhood and adolescence.  Between the 8 faculty, there are scheduled surgical cases and outpatient clinics 5 days a week, providing ample opportunity for exposure to all facets of pediatric urology.

With guidance from the program director, the pediatric urology fellow will select surgical cases on which to scrub.  He/she will be expected to be the primary surgeon or teaching assistant on all index cases, when possible.  After gaining adequate surgical experience the pediatric urology fellow will be given the opportunity to be the teaching assistant on all other cases when scrubbed.  All surgical cases will be directly supervised by the assigned attending physician and fellows will not operate independently.

The pediatric urology fellow will also be tasked with running the clinical pediatric urology service.  First and foremost, the fellow is expected to oversee the care of inpatients on the service as well as active consults.  Additionally, the fellow will be responsible for overseeing the rotating (3 pgy-4 urology) residents and medical students on the service.

In addition to direct patient care, there is a weekly radiology/case-management conference as well as educational conference for residents.  Working with the residents, the fellow is responsible for overseeing the cases which are presented at radiology conference as well as preparing a brief educational review based on a rotating schedule.

The pediatric urology fellow will be evaluated quarterly by all attending physicians involved in the training program as well as by the general urology residents he/she has supervised. The pediatric urology fellow will meet with the Program Director quarterly to review these evaluations and discuss his/her progress. 

How to Apply

How to Apply

The only documents that we expect in order to consider your application complete include:


Interview days provide the applicants with an opportunity to not only interview with most of the faculty, but to also see how our department functions during a regular day.  All interviews are conducted on Tuesdays, and during the hospital tour you are likely to observe one of the faculty in the OR, or the clinic.  Our weekly radiology conference at the end of the day is where challenging cases are presented for discussion by the entire faculty.  Most applicants arrive to Washington, D.C. on Monday and leave on Wednesday.  Candidates are welcome to come for second look visits, but they are not expected.

Typical Interview Day Schedule

Faculty Interviews - 8:30 am to 12:00 pm
Lunch and Tour with Research Fellow - 12:00 pm to 1:00 pm
Faculty Interviews - 1:00 pm to 4:30 pm
Radiology Conference - 4:30 pm to 6:00 pm
Dinner with Faculty - 6:30 pm to 9:00 pm
Return to Hotel - 9:15 pm

Fellowship Coordinator

Misha Meyer

Typical Interview Season Schedule

Registration Open - Middle of November
Registration Deadline - Beginning of May
Children's National Interview Period - Beginning of February to End of April
Rank List Open - Beginning of May
Rank List Due - Beginning of June
Match Results Released - Middle of June

Hotel Arrangements

We have arranged for a reduced rate at One Washington Circle Hotel.

1 Washington Circle Northwest
Washington, DC 20037

When you call to make your reservation, please say that you are interviewing with “the department of Pediatrics at George Washington University”.


Arriving by car: Parking is available in the on-site garage

Arriving by Taxi or Ride Share: There is a patient/ visitor drop-off point at the garage entrance

Arriving by Metro: The hospital operates shuttle buses that pick up hospital staff, patients and visitors outside the Columbia Heights stop on the Green/ Yellow Line, and the Union Station and Brookland stops, which are both on the Red Line. 

Faculty and Staff

Faculty and Staff

H. Gil Rushton, MD is fellowship trained in pediatric urology and Chairman of the Division of Urology.  He has practiced in the Washington area since 1986.  He served as a past Secretary and Chairman of the American Academy of Pediatrics Section on Urology, the Executive Secretary of the Pediatric Urology Advisory Council to the American Board of Urology and as the Section Editor for the Journal of Urology, Pediatric Section.  He oversees all aspects of the department, including the clinical supervision and experience of the trainee, and division operations.  He has the opportunity to spend one-on–one time with the fellow, both in the operating room and in outpatient clinics.  He determines if the trainee has weaknesses in any specific areas and will insure that those are addressed.  He meets with the Program Director (Dr. Hans Pohl) regularly to evaluate the trainee's progress and informs the Program Director of the trainee's strengths and deficiencies.  He meets with the faculty semiannually to discuss the program and review the fellow’s progress. 

  • Medical School: Medical University of South Carolina, 1974-1978 
  • Residency: Medical University of South Carolina, 1979-1983 
  • Fellowship: Hospital for Sick Children, London, 1983Emory University, 1985-1986 
  • Phone: 202-476-3362 
  • Email: 
  • Subspecialty interests: Vesicoureteral reflux and UTIs, perinatal hydronephrosis, and reconstruction of hypospadias and ambiguous genitalia 

Hans G. Pohl, MD is fellowship trained in pediatric urology and is Director of Research for the Division, Program Director for the Fellowship, Associate Chief of the Division of Urology and Medical Unit Director for Perioperative Services.  Dr. Pohl is a member of the Program Director’s Committee for Pediatric Urology, an associate editor for the Journal of Urology, and reviewer for Journal of Pediatric Urology. Dr. Pohl joined the faculty at Children’s Hospital in 2002 and has focused his research interests on urinary tract infection, vesicoureteral reflux, UTI associated renal scarring and hydronephrosis.   He has participated in various NIH funded clinical trials (RIVUR, CUTIE, STARRS), externally funded projects (Impact of Self-Management with Probiotics on Urinary Symptoms and the Urine Microbiome in Individuals with Spinal Cord Injury (SCI) and Spina Bifida (SB)) and internally funded projects (Congenital Urinary Biomarkers in Hydronephrosis).  He is responsible for the academic and investigatory portions of the fellow’s experience as well as supervising experience in the outpatient clinic and operating room. He also participates in all conferences and leads the monthly research conference. 

  • Medical School: George Washington University Medical School, 1988-1992 
  • Residency: George Washington University, 1992-1998 
  • Fellowship: National Institutes of Health, 1998-2000 | Boston Children’s Hospital, 2000 - 2002 
  • Subspecialty interests: Complex reconstructive problems, exstrophy/epispadis complex, urinary incontinence associated with spina bifida 
  • Phone: 202-476-5042 
  • Email:

Naida Kalloo, MD joined the Division is fellowship trained in pediatric urology and is Director of the comprehensive Voiding Dysfunction Clinic. She joined the faculty of the Division of Urology in 2003 after serving for 7 years as the attending pediatric urologist at the National Naval Medical Center in Bethesda, MD. She will have the responsibility of educating the fellow regarding this complex but common pediatric problem and is also involved in supervising surgical experience. 

  • Medical School:  Howard University Medical School, 1981-1985 
  • Residency: Emory University (General Surgery), 1985-1987 | Howard University (Urology), 1987-1991 
  • Fellowship: Johns Hopkins University Hospital, 1991-1994 
  • Subspecialty interests: Elimination dysfunction, including both diurnal and nocturnal enuresis 
  • Phone: 202-476-5042 
  • Email:

Michael Hsieh, MD, PhD was recruited to Children’s National and the George Washington University to serve as Director of Transitional Urology. This joint venture is the East Coast's first clinical program dedicated to the care of adolescents and young adults with congenital urologic disorders.  Many of these patients have chronic cystitis and are at increased risk of bladder cancer, diseases which dovetail with Dr. Hsieh’s research interests.  Dr. Hsieh also is the Stirewalt Endowed Director of the Biomedical Research Institute near Children’s National’s satellite facilities in Rockville, MD, where he runs a bladder biology research group and is developing a broader microbiology research program across multiple laboratories.

  • Medical School:  Jefferson Medical College 2001 
  • Residency:University of California at San Francisco (General Surgery), 2002 | University of California at San Francisco (Urology) 2007 
  • Fellowship: Texas Children's Hospital 2009 
  • Phone: 202-476-5042 
  • Email:

Massoud Majd, MD, is an internationally known expert in the field of Nuclear Medicine. He frequently supervises the weekly Uro-radiology conference in which capacity he lends his broad expertise in the indications for and interpretations of various diagnostic radiographic tools. He has produced landmark work in the field of pediatric urology nuclear imaging.

Aaron Krill, MD, joined our division in January of 2016.  Dr. Krill’s fellowship training emphasized traditional open surgery, as well as laparoscopic and robotic surgery.  He considers it his mission to apply minimally invasive and robotic techniques whenever possible to improve outcomes and decrease morbidity in pediatric reconstructive urologic surgery.  Dr. Krill’s areas of research interest include adolescent varicoceles, antenatal hydronephrosis, congenital solitary kidneys and ureteroceles. 

  • Medical School:  Rush Medical College, 1999-2003 
  • Residency: George Washington University, 2003-2010 
  • Fellowship: Hofstra-North Shore-LIJ Cohen Children's Medical Center of NY, 2010-2012 
  • Phone: 202-476-5042 
  • Email:

Tanya Davis, MD, completed her Urology residency at the Medical College of Wisconsin (Milwaukee, Wisconsin), and prior to that received her MD degree from Albany Medical College (Albany, New York). She is a graduate of the Leadership in Medicine Program at Union College (Schenectady, New York), where she simultaneously completed her undergraduate work and an MS in Healthcare Management.

She was initially drawn to Pediatric Urology as a sub specialization of Urology due to the special nature of the relationship between a physician, child and their family and fostering this relationship is a top priority in her practice.  Her clinical interests range from common, outpatient procedures to more complex reconstructive surgery and minimally invasive, robotic surgical techniques. Her research interests relate to quality improvement and process mapping, with the goal of helping patients and their families receive the best possible urologic care in an efficient (and safe) manner.

Dan Casella, MD.  Originally from Baltimore, MD, Dr. Casella will be joining the faculty after completing his pediatric urology fellowship at Vanderbilt University.  He earned his undergraduate degree in molecular biology at The University of Colorado at Boulder, attended Eastern Virginia Medical School and completed his residency at The University of Pittsburgh.  Throughout his training, Dr. Casella has maintained a strong interest in basic science research, participating in studies examining the molecular epidemiology of bladder cancer, programmed cell death, and ureteral development.  His research is currently focused on novel mechanisms of modulating bladder function through peripheral nerve (posterior tibial) stimulation, and the molecular mechanisms which drive cloacal membrane and genital tubercle development. 

  • Subspecialty interests: treatment of hypospadias, end stage voiding dysfunction and disorders of sexual differentiation
Frequently Asked Questions

Frequently Asked Questions

Q: What is the expected salary?

The fellowship pay scale is based on ACGME compensation standards and varies by PGY. 

Q: What are the benefits?

  • Health, Dental, Vision
  • Flexible Spending Accounts
  • Life Insurance
  • Annual & Sick Leave
  • Disability Insurance
  • Employee Assistance Program
  • Backup Child and Elder Care
A detailed summary of all benefits can be found in our Benefits Guide.

Q: What is the call schedule for fellows?

During the week, the pediatric urology fellow will take secondary call by phone, providing back-up to the general urology resident on primary call.  The fellow will also take primary call for one weekend a month.  An attending pediatric urologist will always be on call and the pediatric urology fellow will have no completely independent patient care.  However, the fellow will be granted graduated responsibility throughout the year, with the goal of producing a well-trained pediatric urologist.

Q: Do I need to have a basic science background for the research year?

It is not expected that incoming fellows will have prior basic science research experience. Fellows will work closely with Drs. Hsieh and Casella, or other members of the research staff, to ensure that they are trained in basic lab skills and procedures.  

Q: Is the research year fully funded?

Funding for the ongoing projects is established and it is not required nor anticipated that fellows will apply for funding to support the efforts of their research.

Q: Will I be considered junior faculty?

The fellow will always be under the direct supervision of an attending physician and will not be a billable provider.

Q: Are there other locations where patients are seen besides the main hospital in D.C.?

  • Primary inpatient facility: Children’s National Medical Center Sheikh Zayed campus
  • Secondary inpatient facilities: Georgetown University Hospital and Inova Fairfax Hospital
  • OR locations: Children’s National Medical Center Sheikh Zayed campus, Pediatric Specialists of Virginia (ASC), Inova Fairfax Hospital, Montgomery County Regional Outpatient Center (ASC)
  • Outpatient clinical locations: 9 locations in D.C, Northern VA, and southern MD, on a rotating basis.        
Contact Information

Contact Information

Fellowship Coordinator (manager):  
Misha Meyer
Phone: 202-476-6289
Fax: 202-476-4739


Hans G. Pohl, MD, FAAP
111 Michigan Ave, NW, Washington, D.C. 20010
Phone: 202-476-2681
Fax: 202-476-4739