About the Moderators

Moderator & THP Hypospadias Editor
Mark Zaontz, M.D.
Children's Hospital of Pennsylvania, Philadelphia, PA

Mark Randall Zaontz, M.D., is an attending pediatric urologist in the Division of Urology at The Children's Hospital of Philadelphia.

Areas of Expertise: Hypospadias, Vesicoureteral Reflux, Hydronephrosis, Complex Genitourinary Reconstruction

Dr. Zaontz received his medical degree from Georgetown University. He completed his surgical residency at St. Vincent Catholic Medical Centers in New York City followed by his residency in urology back at Georgetown. He completed his fellowship in pediatric urology at Children’s Memorial Hospital in Chicago and stayed on as an attending post training.

Dr. Zaontz then joined Cooper Hospital/University Medical Center, a Robert Wood Johnson Affiliate, where he was head of the section of Pediatric Urology and rose to the rank of full professor in Urology.

Following his time at Cooper, Dr. Zaontz led a large private practice in pediatric urology and served as the head, section on Pediatric Urology and director of pediatric subspecialties in the Virtua Health System in Voorhees, New Jersey. He is clinical professor of urology with Temple University School of Medicine. He is board certified in urology and holds a certificate of added qualification in pediatric urology.

Dr. Zaontz has developed a national and international reputation for his experience in reconstructive pediatric urology. He has consistently been recognized in the “Best Doctors in South Jersey,” “Best Doctors in New Jersey” and “Best Doctors in America” lists since 2005 and has been voted a Philadelphia Magazine “Top Doc for Kids” nine times.

Dr. Zaontz has published and lectured extensively and has particular expertise and interest in caring for patients with hypospadias and congenital malformations of the genitourinary tract, including vesicoureteral reflux and hydronephrosis. He is constantly working toward reducing morbidity and improving outcomes in these children.


Christopher J. Long, M.D.
Children's Hospital of Pennsylvania, Philadelphia, PA

Christopher J. Long, M.D., is an attending pediatric urologist in the Division of Urology at The Children's Hospital of Philadelphia.

Areas of Expertise: Hypospadias, Minimally Invasive Surgery, Pediatric Urologic Oncology, Stone Disease

Christopher J. Long, MD, has roots in the Philadelphia area, having grown up in Southern New Jersey. He stayed close to home where he received his bachelor’s degree from the University of Pennsylvania and his medical degree from Rutgers New Jersey Medical School. Dr. Long completed his internship and residency in Urology at Temple University Hospital in Philadelphia, and a Pediatric Urology fellowship in the Division of Urology at The Children’s Hospital of Philadelphia.

Dr. Long was awarded the prestigious Urologic Care Foundation Research Scholar Award for his work during his fellowship examining the pathophysiology behind the bladder’s response to outlet obstruction. Expanding upon his research interests, Dr. Long will be part of the team caring for children with neurogenic and non-neurogenic bladder dysfunction.

His additional clinical interests include complex reconstruction, hypospadias, oncology and stone disease, as well as applying both laparoscopic and robotic-assisted minimally invasive techniques to pediatric genitourinary reconstruction.

Dr. Long’s clinical research interests include the renal trauma experience at The Children’s Hospital of Philadelphia along with establishing a standardized assessment model for hypospadias outcomes and risk assessment. His basic science research includes developing and studying collagenase as a potential medical therapy for bladder hypertrophy.


Antonio Macedo, Jr., M.D.
Universidade Federal de São Paulo, Brazil

Antonio Macedo, M.D., is Head of the Pediatric Urology Section at the Universidade Federal de São Paulo in Brazil.
Areas of Expertise:  Hypospadias, Reconstructive Urology, Spina Bifida Cystica, Anorectal Malformation

He earned an M.D. from the University of São Paulo in 1989 and a Ph.D. in Urology from Johannes Gutenberg Universität, Mainz, in 1996.

In 2001, Dr. Macedo was an associate professor at UNIFESP. He was a Visiting Professor at the University of California—San Francisco in 2012 and at Hebrew University in Israel in 2016.

In 2011, Dr. Macedo was considered a `top-ten` manuscript reviewer at the Journal of Pediatric Urology and has been an Assistant Editor there since 2012. Also, he is currently a member of the editorial board of the Journal of Urology.

As an educator, Dr. Macedo has trained  25 fellows in pediatric urology, mentored 2 students in masters degrees and 21 students in doctors degree.