After completing his studies in medicine and dentistry in Hanover, Prof. Kramer underwent specialist studies at Hanover Medical School and gained the additional title of Plastic Surgeon (Director Prof. Dr. Dr. J.-E. Hausamen). From 2004 to 2018, he worked as Senior Consultant at the Department of Oral and Maxillofacial Surgery at Goettingen University Hospital (Director: Prof. Dr. Dr. H. Schliephake). Since August 2018, he has been the Director of the Department for Oral and Maxillofacial Plastic Surgery at Bonn University Hospital.

Scientifically, Prof. Kramer has focused on the influence of signal peptides on osteoblast differentiation and on different concepts for promoting bone healing and skeletal reconstruction. His clinical focus is on the field of reconstructive oral, jaw and maxillofacial surgery.