If you suffer from kidney stones, a regular ride on a mildly thrilling rollercoaster could be the preventative medication you need.
A team of urologists 3D-printed a patient’s kidney from clear silicone, filled it with urine and three kidney stones, and strapped it to Disney World’s Big Thunder Mountain Railroad rollercoaster to prove this.
The resulting study, published in The Journal of the American Osteopathic Association, was carried out after a growing body of anecdotal evidence pointed to rollercoasters helping patients pass kidney stones before they reached operable sizes.
“Passing a kidney stone before it reaches an obstructive size can prevent surgeries and emergency room visits,” said co-author David Wartinger, professor of urology at Michigan State University College of Osteopathic Medicine.
The study was also carried out to prove the efficacy of 3D-printed replica kidneys like the one used. It was modelled on a specific patient who had ridden Big Thunder Mountain three consecutive times, passing a kidney stone after each ride. Kidney stones of different sizes were used, and the model was engineered so they could be slotted in different locales: the upper, middle and lower kidney.
The kidney had its own seat on the ride, between the two researchers - Wartinger and coauthor Marc Mitchell. It was positioned at an anatomically correct angle within a backpack strapped to the seat, through the use of strategically placed padding. The co-authors rode Big Thunder Mountain in multiple positions - for science - a total of 60 times. And discovered that if you really want to shake a kidney stone free, you are better off sat at the back of the ride: the back seat had a 63.89 percent success rate, while the front 16.67 percent.
The pair also calculated the kidney stone volume and location that best suited the “treatment”. The researchers concluded: “Rollercoaster riding after treatments like lithotripsy and before planned pregnancies may prevent stone enlargement and the complications of ureteral obstruction.”
Perhaps most important for the purposes of the investigation, the co-authors also rode other rollercoasters within the Orlando-based theme park. They found the more well-known Space Mountain did not make the cut. Big Thunder Mountain, with its top speed of 35mph, twin tubular steel rails that never go upside down, and conservative 2 minutes and 30-second ride-length, proved to be the best model for the study.
According to the NHS, three in 20 men and two in 20 women are likely to develop kidney stones at some point in their lives. As well as being an excruciating issue for the patient, in the US alone it costs around $2.1 billion to treat kidney stone patients every year.
As a result, the study authors are highlighting a way to prevent the problem becoming a surgical one, in a low-cost way. “The osteopathic philosophy of medicine emphasises prevention and the body’s natural ability to heal. What could be more osteopathic than finding a relatively low-cost, non-invasive treatment that could prevent suffering for hundreds of thousands of patients?” Whether this potential course of treatment is, indeed, “low-cost” is debatable. So far the team has only verified that Big Thunder Mountain would be effective, and entry to the park for one day comes in at more than $100. Health insurance companies in the US are probably not going to pick up that bill.
There’s also the added complication that rollercoasters have themselves been subject to investigations of a very different kind in the past.
A 2010 study by doctors at the Henry Ford Hospital in Detroit found that the quick change in pressure induced by some high-speed rollercoasters can cause an ear injury, ear barotrauma, which can lead to temporary hearing loss, along with dizziness and pain. There have also been documented, but incredibly rare cases, of rollercoasters inducing strokes.