Obituary for Dieter Felsenberg

Dieter Felsenberg passed away on 6 July 2020 at the age of 74. As several obituaries testify, he was one of the most influential scientists of the German osteological community. With this—perhaps somewhat unconventional—tribute from our personal perspectives, we would like to express our grief over the loss of a very exceptional personality.

During his career, Dieter gradually formed an increasingly complex body of thoughts on the structure and function of the bone. He began as a radiologist, but soon went beyond this field. Motivated by constant curiosity, he quickly adopted alternative, often controversial viewpoints. He was loyal to QCT, but pragmatically accepted DXA. He regularly questioned conventions and expert opinions if they contradicted his scientific findings or were not easily verifiable. With his thinking across disciplines and faculties, he was ahead of his time. Bone mechanics was the next field on which he worked with passion. Harold Frost’s “Utah Paradigm” was a plausible theory for him—at odds with the hormone-centered thinking of his internal medicine colleagues. Force effects dominated, their reduction in weightlessness fascinated him, and he explored this in his Berlin Bedrest Studies and by personally taking part in parabolic flights “see Figure next page”. The logical consequence was the inclusion of muscle on the next level of his thought system: interactions of bone and muscle, not only those of a mechanical nature but also through metabolic processes. In later phases, he expanded his research to the interaction of mechanics and genetics in osteoporosis.

Dieter Felsenberg was an eminence with authority; his voice was always heard, also because one knew that he represented his opinion from deepest innermost scientific conviction. Yet, a great strength of Dieter was his ability to accept and respect other opinions and conclusions as long as they were scientifically justifiable. This openness and the desire to impart knowledge formed the basis of a specifically for this purpose created evening lecture series, the “Berliner Knochengespräche” (Berlin bone conversations). Bone experts from all over the world were honored to be invited and came with pleasure to lecture on their research topic. The evenings usually ended with good food and wine and lively discussions at a nearby restaurant since work and pleasure were two corresponding poles of his passion.

Everyone who was connected with him knows his bear hug; it seemed for a moment as if he gave you all his attention—but Dieter had seemingly inexhaustible energy for many, many friends. This positive energy helped to create a community of osteologists in the German-speaking world and internationally. Dieter was always on the move, always eager to discover new horizons, new and old friends; for this, he constantly traveled the world. In parallel, he expanded his research group into the Center for Muscle and Bone Research, which became a center of gravity for clinical studies on osteoporosis in Germany.

Dieter wanted to break down the barriers between basic research and clinical application. Clinical need should guide basic research, and a good clinician should base his actions on scientific evidence. Consequently, he expected at least a minimum of clinical interest from basic scientists in order to conduct their research accordingly, aiming at clinical relevance.

During the last years of his life, all aspects of his work seemed to flow together when Dieter focused on individual patients/people with their diseases, their questions, wishes, and individual challenges. Many came to him as a “last resort” because no one else had an answer. Rare diseases and complex questions captivated his interest in particular. He used all his experience as a scientist, doctor, and human being to find the optimal answer, diagnosis, and therapy for each individual. His approach was always personalized medicine at eye level with the patient, adapted to the patient/human being, and the patients appreciated his dedication, empathy, and wisdom.

He wanted to understand in order to be able to act and make the right decisions and always share his insights with others. We are all deeply grateful to Dieter for allowing us to share our professional and private lives with him. We will miss him very much.