Michael Bailey – mbailey@uw.edu
Center for Industrial and Medical Ultrasound
Applied Physics Laboratory
University of Washington
1013 NE 40th St.
Seattle, WA 98105, USA
apl.uw.edu/pushingstones
Popular version of paper 2pBAa1
Presented Tuesday afternoon 1:00 pm, November 6, 2018
176th ASA Meeting, Victoria BC
We are trying to change the way kidney stones are managed. Our solution is a painless, one-hour session where stones are identified, broken, and expelled from the kidney to pass naturally. This is an update on current progress to the doorstep of FDA clearance of an expelling system and first in human trials of a stone breaking system.
Stones are common and are currently managed in a long, costly, painful process. One in 11 Americans will have stones and cost of disease is $10B annually in the U.S. Stones are painful when they obstruct urine flow out of the kidney. Most people go to the Emergency Department where they to sent to a radiology department for a CT exam and then are given pain medication. They are expected to pass the stone within 3 weeks. If pain cannot be managed a surgery is performed to allow urine out of the kidney but not to remove the stone. If the first surgery has been performed, the stone is too large to pass or does not pass, or symptoms cannot be controlled, the patient has surgery to break the stone or stones usually with the expectation of the patient passing the fragments naturally. About one-third of surgeries leave fragments that can grow to again be symptomatic stones. Recurrence requiring intervention is about 50% within 5 years. Patients after the second stone event are usually monitored by CT annually for new stones. This process subjects patients to pain, anxiety, and ionizing radiation over a long time.
Our talk presents an update on our new non-invasive stone removal technology. We will present progress and results of several parallel clinical trials. Our NASA-funded study is to reposition an obstructing stone in the Emergency Department to relieve pain. One NIH-funded study is a randomized clinical trial to measure long term benefit of expelling fragments that remain after surgery. The status and design of studies to test the complete imaging, breaking and expelling technology will also be discussed. So far over 50 subjects are participating in the clinical trials.
We also will mention plans to improve the technology and further expand its use. This includes outputs to break stone faster based on image guided feedback of the progression of the individual’s specific procedure and stone characteristics. It also includes tractor beam technology to grab and steer stones and fragments through the complex three-dimensional path out of the kidney. Other talks in the session provide more detail on the development of these additional technologies.
Figure 1 shows a movie taken from a camera inside a patient’s kidney while the ultrasound sent from a probe on the patient’s skin causes an 4-mm (1/4 inch) kidney stone to move out of the kidney.
Figure 2 is a drawing of the new system and process.