 In the ensuing years, he studied surgery with Bernhard von Langenbeck (1810-1887) and Heinrich Adolf von Bardeleben (1819-1895), later being appointed chief physician of the surgical department at the Städtisches Krankenhaus in Aachen (1881).In 1888 he became director of the surgical clinic at the University of Jena.Riedel was a pioneer in the surgical treatment of appendicitis and cholecystitis.