The physicians

Who treats you.

Dr Tonninger-Bahadori has built the endoscopy centre since 2016 and since the start of 2026 has been running it as a group practice together with Dr Hamzo-Assad. Both are specialists in General and Visceral Surgery, supported by experienced visiting physicians.

Dr Katayoun Tonninger-Bahadori, MD, F.E.B.S.

Specialist in General and Visceral Surgery · Specialist in Paediatric Surgery · Emergency physician · Head of the Endoscopy Section, Vienna Medical Chamber

Dr Tonninger-Bahadori has led the practice at the Floridsdorf location since 2016 and has for many years headed the Endoscopy Section of the Vienna Medical Chamber. She is F.E.B.S. (Fellow of the European Board of Surgery) — the European certification in surgery.

In her role on the chamber she contributed significantly to two developments that have visibly improved access to prevention: sedation costs for colonoscopy and gastroscopy have been covered by statutory health insurance since 2018, and the recommended starting age for preventive colonoscopy was lowered to 45.

She completed her studies and specialist training at the Karl-Franzens University of Graz (doctorate 1995), where she also worked for many years as a student assistant at the Institute of Anatomy (1991–1997). After her studies she spent time as a visiting physician at the Mayo Clinic Rochester (Minnesota). She qualified as a specialist in Paediatric Surgery in 2003 and in General Surgery in 2006, adding the emergency physician diploma in 2015. With her dual specialist qualification she joined the Kaiserin Elisabeth Hospital in Vienna in 2008, well known for its thyroid surgery — where her thyroid-surgical focus began, which she has consistently developed since.

Today she operates on the thyroid — over 2,000 procedures — at Privatklinikum Döbling. At the practice in Floridsdorf she assesses whether an operation is appropriate and necessary, and handles the pre- and post-operative care around the procedure. A general thyroid clinic (hormone status, metabolism) is not offered here. She regularly teaches international online courses on thyroid diagnostics.

“Healing begins, in no small part, with proper information. The more information, the fewer fears.”

  • Studies at Karl-Franzens University of Graz (1989–1995)
  • Dual specialist (Paediatric Surgery 2003 · General Surgery 2006)
  • Emergency physician (diploma 2015)
  • F.E.B.S. — Fellow of the European Board of Surgery
  • Head of the Endoscopy Section, Vienna Medical Chamber
  • Thyroid focus since 2008 · over 2,000 procedures
  • Languages: German, English, Persian
Portrait of Dr Katayoun Tonninger-Bahadori

Dr Nisrin Hamzo-Assad, MD

Specialist in General and Visceral Surgery · General practitioner · Emergency physician

Dr Hamzo-Assad studied human medicine at the Medical University of Vienna (doctorate 2008). She obtained the emergency physician diploma and the diploma in General Practice in 2012, and the specialist diploma in General and Visceral Surgery in 2021.

She gained the bulk of her surgical experience over more than eleven years at the Regional Hospital Mistelbach (2009–2020). Since September 2020 she has additionally been working as a visiting physician in outpatient practices in Vienna — focusing on endoscopy. This combines over four years of practice-based endoscopy experience with her hospital routine.

Since September 2024 she has been part of our practice — initially as a visiting physician, since the start of 2026 as a partner in the group practice. She performs all endoscopic examinations (colonoscopy and gastroscopy) and runs general and visceral-surgical consultations.

  • Studies at MedUni Vienna (1999–2008)
  • Emergency physician (diploma 2012)
  • General practitioner (diploma 2013)
  • Specialist in General and Visceral Surgery (diploma 2021)
  • 11+ years at Regional Hospital Mistelbach
  • Languages: German, English, French, Arabic, Aramaic (native)
Portrait of Dr Nisrin Hamzo-Assad

Hand in hand with Vienna hospitals

We work closely with experienced surgeons from Vienna hospitals. They support the practice as visiting physicians with strong clinical quality — and at the same time create direct connections to the hospitals where they work.

If after an examination in our practice a hospital procedure or further treatment is needed, the paths are short: we can hand you over directly to familiar hands — without detour, without waiting for a first assessment. This ensures quick, seamless care also beyond the practice.