On the subject of whether or not any of it is still useful:
One of Leonardo’s modern-day proponents is a British heart surgeon, Francis Wells. Doctor Wells specializes in mitral valve repair operations. Typically, this type of repair is accomplished by narrowing the valve’s diameter to restrict backflow, but after studying Leonardo’s anatomical analyses of the heart, the surgeon discovered there was a better way, thanks to Leonardo’s identification of the opening phase of the valve’s movement as crucial to the overall cycle. With this new knowledge, Doctor Wells has modified his mitral valve repair procedures and successfully treated 80 patients, restoring them to a quality of life previously not possible. He suggests, “Leonardo had a depth of appreciation of the anatomy and physiology of the body—its structure and function—that perhaps has been overlooked by some,” and is studying the rest of Leonardo’s anatomical work in hopes of finding other refinements to modern procedures.
Even more compelling is Leonardo’s influence on the cutting edge of modern medicine—the development of precision robots to assist in surgical procedures. Leonardo himself, despite his prescience in so many other technological areas, may have been surprised to learn that since 1983, some surgeries have been accomplished with robotic tools. There is some reason to think Leonardo may have anticipated this eventuality, however; in 1495, Leonardo designed and built one of the first humanoid robots, a mechanical knight capable of sitting up, turning his head, and waving his arms, all in time to the sounds of artificial drums. When modern-day robotics expert Mark Rosenheim set out to duplicate this robot, it took him five years of work, and in his research he discovered:
Leonardo’s anatomical drawings were unique and gave him the information needed to emulate the complex joints and muscles of the human body. The wrist joint, which is one of the body’s most complicated joints, presented challenges to robot design. However, Leonardo’s principles enabled engineers to construct a suitable model. It is from these and other experiments that the first prototype for robotic surgery was developed.
And so in 1998, the first da Vinci robot-assisted surgery, a heart bypass, was performed, inaugurating a career for the telepresence tool that has resulted in over 200,000 surgeries performed by a robot designed in part with the help of Leonardo’s anatomical studies. Each of these procedures was safer, faster, and less invasive compared to the non-robotically-assisted alternative, and each patient has Leonardo’s work to thank for their speedy and comfortable recovery. As of 2009, there are over 1,600 da Vinci robots installed worldwide, performing minimally-invasive laparoscopic surgeries to treat heart, prostate, kidney, bladder, and testicular issues, from malignant tumor removal to complete organ transplant.