Two scientists carried a urine-filled, 3D-printed kidney onto Disney World rides in the name of science. Sixty rides later, they confirmed that getting jostled in a roller coaster makes it easier to pass kidney stones.
Kidney stones are incredibly painful mineral deposits found in urine. Passing them is notoriously painful (and has been frequently declared "more painful than childbirth"). So the results of this study, published today in the Journal of the American Osteopathic Association, suggest a simple technique for quickening the passing of stones that almost anyone can try.
Study co-author David Wartinger, a urologist at Michigan State University, got the idea after patients kept telling him success stories related to their spring break vacation. "The moment one of my students and I realized we had to move forward was hearing from a patient who rode the ride three times and after each consecutive ride he passed a stone," he told Gizmodo.
To test the theory, Wartinger and co-author Marc Mitchell 3D printed a silicon kidney based on an organ belonging to a male patient. They filled it with that patient’s urine, sealed it, and then went to Disney World to gather data.
The two rode the Big Thunder Mountain Railroad 20 times, holding the silicon kidney between them in a backpack at roughly the same height as if it were inside someone. They also took 20 rides each on Space Mountain and Walt Disney World railroad, but focused most of their researcher on Thunder Mountain.
It’s important to note that Big Thunder is not a terrifying ride. It makes sharp left and right turns, but doesn’t have huge drops or climbs and children often ride it. Still, even this moderate movement showed promising results: sitting in the back of the Big Thunder Mountain Railroad caused stones to be passed by the silicon kidney 64 percent of the time. Sitting in the front caused the stones to be passed 17 percent of the time.
Unsurprisingly, the rides were most effective for small kidney stones, meaning those under 4 millimeters. The researchers are now interested in other rides though Wartinger notes that it’s not exactly fun for him. "By trip 20," he tells NBC, "the novelty is gone."