Doctors may soon be prescribing trips to Disney World, after researchers discovered that taking a ride on one of its most iconic roller coasters can help kidney stones pass through the urinary system out of the body.
The study, which appears in the Journal of the American Osteopathic Association, was inspired by anecdotal reports about people passing their kidney stones after enjoying a spin on the Magic Kingdom’s Big Thunder Mountain Railroad. One man even claimed to have gone on the roller coaster three times in a row, passing one stone after each ride.
To figure out how reliable these claims were, the team created a 3D-printed model of that particular patient’s kidney, which they filled with urine before placing a real kidney stone in each of its upper, middle, and lower passageways. They then took their model with them as they rode Big Thunder Mountain 20 times, before analyzing the movement of these stones.
Amazingly, they found that stones placed in the kidney’s upper passage were dislodged on all 20 rides, although those in the lower passageways were somewhat more stubborn. They also found that sitting at the back of the ride led to a passage rate of just under two in three, while sitting at the front caused a passage rate of one in six.
The 3D-printed kidney that researchers took on the roller coaster with them. G.L. Kohuth, Michigan State University
Kidney stones form when calcium, ammonia, and cysteine build up into crystalized clumps as the kidneys filter them out of the blood. When these stones reach a certain size, they can block the ureter, which connects the kidneys to the bladder, or the urethra, which carries urine out of the body. This can cause intense pain and can lead to urinary tract infections if left untreated.
Large stones normally have to be surgically removed, although smaller stones are sometimes spontaneously passed out of the body in urine. In their study, the researchers found that riding on roller coasters can increase the likelihood of these smaller stones passing without the need for any intervention, thereby preventing the build-up of large stones.
Study co-author David Wartinger commented that “passing a kidney stone before it reaches an obstructive size can prevent surgeries and emergency room visits. Roller coaster riding after treatments like lithotripsy and before planned pregnancies may prevent stone enlargement and the complications of ureteral obstruction.”