Volume 3 Supplement 1

Current and Future Applications of Focused Ultrasound 2014. 4th International Symposium: abstracts

Open Access

Preliminary results of the initial human clinical trial of focused ultrasound to reposition kidney stones

  • Michael Bailey1,
  • Barbrina Dunmire1,
  • Bryan Cunitz1,
  • Jonathan Harper1,
  • Franklin Lee1,
  • James Lingeman2 and
  • Mathew Sorensen1
Journal of Therapeutic Ultrasound20153(Suppl 1):O71

https://doi.org/10.1186/2050-5736-3-S1-O71

Published: 30 June 2015

Background/introduction

Ultrasonic propulsion is a new technology we have developed which uses focused ultrasound to transcutaneously reposition kidney stones. Two applications are expelling small stones or fragments and dislodging obstructing stones. We report preliminary, investigative findings from the first use of this technology in humans.

Methods

There are three arms of the study: de novo stones, post-lithotripsy fragments, and large stones within the preoperative setting. A pain questionnaire is completed immediately prior to and following propulsion. A maximum of 40 push attempts are administered on either low (50 V) or high (90 V) power settings. Movement is classified as no motion, movement with rollback (2-3 mm), or movement to a new location (> 3 mm) (Table 1).
Table 1

Ultrasonic Propulsion of Kidney Stones - Preliminary Results. All subjects treated with a combination of 50 V and 90V output

Study Arm

Patient #

Number of Stones

Stone size (mm)

 

Motion Grading

 

Total Push Bursts

2-3mm

>3mm

Passed stones

De-Novo Stones

1

3

2-3

5 (19%)

0

N

27

2

5

2-3

16 (41%)

0

N

39

3

2

3

1 (4%)

0

N

23

Post-Lithotripsy

4

2

2

23 (62%)

5 (13%)

Y

37

5

5

2-3

21 (53%)

2 (5%)

Y

40

6

Multiple

< 2

12 (30%)

4 (10%)

Y

40

7

Multiple

2-5

5 (13%)

20 (50%)

unclear

40

Pre-operative

8

2

7

7 (26%)

0

N/A

27

Results and conclusions

Eight subjects have been enrolled and undergone ultrasonic propulsion to date. None of the subjects reported pain associated with the treatment. Subjects did report a mild warming of the skin with high (90 V) power pushes; no sensation was reported with low (50 V) power pushes. A summary of push movement results is provided in Table 1. Stones were visualized and repositioned in all subjects. One subject in the post-lithotripsy arm passed two small stones immediately following treatment. At least three post-lithotripsy subjects reported passage of multiple small fragments within two weeks of treatment. In five subjects, ultrasonic propulsion identified a collection of stones previously characterized as a single stone on KUB and ultrasound. Pre-operatively, one of two 7 mm stones was move before surgery. In surgery, it appeared one stone was firmly attached to Randall’s plaque and the other stone had been detached from Randall’s plaque and a 4 mm piece moved into the ureter. There have been no treatment related adverse events reported with mean follow-up of 3 months.

This is the first report of the successful repositioning of kidney stones in humans using ultrasound. Treatment was therapeutic in four subjects and provided diagnostic information in five. Subjects who did not have significant movement were the first patients and in the de novo arm. To date, there have been no reports of pain or adverse events associated with this treatment.

Declarations

Acknowledgements (Funding)

Trial supported by NSBRI through NASA NCC 9-58. Research and development supported by NIH DK043881and DK092197.

Authors’ Affiliations

(1)
University of Washington
(2)
Indiana University

Copyright

© Bailey et al; licensee BioMed Central Ltd. 2015

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

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