From 1999 to 2000, Hölzle was a scientific employee at the Department of Oral and Maxillofacial Surgery at the University Hospital Charité, Campus Virchow Clinic, Berlin.

Between 1992 and 2010, Hölzle was influenced positively by Klaus-Dietrich Wolff, culminating at the Rechts der Isar Hospital of the Technical University of Munich.

From 2007 to 2011, he was senior physician and deputy director of the Department of Oral and Maxillofacial Surgery at the Rechts der Isar Hospital of the Technical University of Munich.

Scientific publications appeared on objectifying valuation of the viability of the transplanted tissue [1] and on the monitoring of different compound composite flaps.

[5][6] In Hölzle´s department of Oral and Maxillofacial Surgery the first computer planned, microsurgical and less invasive deep circumflex iliac artery flap was raised via a medial approach using cutting guides.

He organized and conducted > 100 national and international courses, workshops and meetings in the fields of flap raising, microsurgery, head & neck oncology and implantology.