Ninety and still active in research.

BACKGROUND: Here, we review Prof. Stelzner's career and scientific achievements, which include his personal attitude to genuine creative thinking and its application to surgery and research. DISCUSSION: The stations of his clinical career are highlighted together with his excursions into philosophical and historical topics. From the vast number of publications and research activities, we describe major contributions to morphology including recent contributions through functional examination techniques. We reflect on his research on perianal fistulas. Modern-day understanding of continence of the anal sphincter apparatus and other visceral sphincter systems were fields of his research.
CONCLUSION: His efforts in comparative anatomy and morphology are commended. An open mind throughout his life with sharp scientific reasoning opened him a world of solid arguments based on evidence to prove his view, sometimes after decades. Exemplary are the discussions about the adenoma-carcinoma sequence or his views on anatomical structures limiting the spread of cancer cells. We note his continuing research activities well beyond normal pension age. At the age of over 90, he is still a very sought-after conference speaker.