In a bit of medical research inspired by strange and remarkable patient accounts, a Michigan State University urologist reports that riding a medium-intensity roller coaster such as the Disney theme parks’ Big Thunder Mountain Railroad can result in the painless passing of small, and even a few large, kidney stones.

For best results, ride in the back, where — roller coaster afficionados all seem to agree — the thrills are greatest. Independent of kidney stone volume and location, findings reported recently in the Journal of the American Osteopathic Assn. showed that sitting in the back of the roller coaster resulted in an average passage rate of 63.89 percent. Front-seat rides resulted in a far more modest passage rate of 16.67 percent.

David D. Wartinger, a professor emeritus at Michigan State University’s College of Osteopathic Medicine, initiated the study after a series of patients reported something almost too strange to believe: In the wake of riding Big Thunder at Walt Disney World in Orlando, Florida, these patients said their kidney stones passed painlessly from the kidney through the narrow duct of the ureter and into the bladder.

Using a 3-D printed model of a patient’s kidney, Wartinger and his colleagues implanted three kidney stones of various sizes into the upper, middle or lower passageways of the clear silicone model. Two of those mineral clusters, which can form as the kidney filters waste from the bloodstream, were small-to-moderate size — 4.5 millmeters and 13.5 mm. But a third measured 64.6 mm, a size that would rarely pass without treatment — the administration of ultrasound shock waves, called lithotripsy, designed to break up the deposit and allow it to pass.

The researchers received permission from Walt Disney World first, then concealed the kidney model in a backpack and rode Big Thunder 20 times, varying their seat position between front and back.

After analyzing the location of those three kidney stones at the end of each ride, the researchers concluded that “findings support the anecdotal evidence that a ride on a moderate-intensity roller coaster could benefit some patients with small kidney stones,” Wartinger said.

密歇根州立大学的泌尿专家注意到了一些奇特病例，受其启发进行了医学研究。他们得出报告说玩一趟中等刺激的过山车，比如迪士尼乐园的巨雷山过山车，能无痛排出小粒甚至是一些大颗肾结石。

坐在过山车尾部效果最佳，过山车爱好者都知道坐在后面的座位是最刺激的。近日发表在《美国骨科协会杂志》上的调查报告表示，坐在过山车尾部平均排石率能达到63.89%。而坐在头部，排石率要低得多，只有16.67%。

密歇根大学骨科医学退休教授大卫•沃汀格尔是研究发起者，之前有肾结石患者向他讲述了桩桩难以置信的怪事：他们在佛罗里达州奥兰多的迪士尼乐园玩了巨雷山过山车后，体内的肾结石就毫无痛感地从肾脏经由狭窄尿管排到了膀胱内。

沃汀格尔和同事用3D打印机制造了一位患者肾脏的透明硅胶模型，并把三个大小不一的肾结石放入模型上中下的管道中。肾结石是肾脏在过滤血流垃圾时形成的矿物质颗粒。其中两颗结石小的4.5mm，中等大小的13.5mm。第三颗结石64.6mm大，这种大小的结石只有借助超声冲击波治疗，也即碎石术打碎结石，才能排出体外。

实验前，研究人员先征得了迪士尼乐园同意，然后把肾模型藏到背包中坐了20次巨雷山过山车，期间变换位置，从头部换到尾部。

研究人员每次坐完过山车后都会检查三颗肾结石的位置，得出了如下结论。沃汀格尔说，“我们实验所得验证了病人所述情况，坐中等刺激的过山车可以帮助一些患者排出小块结石。”

(Chinadaily.com.cn)

    Words to Learn 相关词汇

   【泌尿专家】mìniào zhuānjiā urologist specialist in conditions and diseases of the genitourinary system

    【碎石手术】suìshí shǒushù lithotripsy the use of ultrasound, often generated by a lithotripter, to pulverize kidney stones and gallstones