His areas of expertise include rectal cancer, colon cancer, and laparoscopic colon surgery. He is professionally affiliated with Medical City Children's Hospital, Baylor Scott & White Health, and Texas Health Resources. Dr. Simmang attended the University of Texas Medical Branch School of Medicine and subsequently trained at Brooke Army Medical Center for residency. He accepts Blue Cross/Blue Shield, Coventry, and Parkland Community Health Plan, in addition to other insurance carriers. Dr. Simmang has received the distinction of Texas Super Doctors.