The majority of Brödel's illustrations were for Dr. Howard A. Kelly, the Chief of Gynecology, during his employment at Johns Hopkins Hospital. Brödel illustrated for Kelly's two-volume textbook, "Operative Gynecology," which was published in 1898. Its release garnered widespread praise and recognition, cemented Kelly's preeminent status in the field of gynecology, and established Brödel's role as a pioneering medical illustrator. Brödel then went on to work on other books authored or co-authored by Kelly, including those on diseases of the kidneys, ureters and bladder, as well as Kelly's journal articles and monographs. Throughout the illustrative process, Brödel worked closely with Kelly, conferring with each other before the first sketch was drawn. After debriefing, with Kelly, Brödel painstakingly conducted independent medical research and experimented to find the best method to communicate information about complex structures to medical professionals. For example, when Kelly asked for some anatomical data about the blood supply of the kidney, Brödel went to the Pathological Laboratories, got a kidney from the autopsies and washed it out by attaching it by a tube to the tap. Then, he filled the arteries with red paint, the veins with blue, and the ureter with yellow. Using the digesting method he had observed Frank Mall use in Carl Ludwig's laboratory in Germany, he could see various sections of the kidney that resembled a tree branch with small apples lining them, which were the glomeruli of the kidney. Brödel also noticed an avascular area and suggested cutting along this line when looking for kidney stones. He developed what is referred today as Brödel's suture, which can be used to repair a prolapsed kidney.