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Clinical Evaluation of BackStop in Patients Undergoing Ureteroscopic Lithotripsy

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT02122341
Recruitment Status : Terminated (Study has halted prematurely as we were not able to meet our target accrual.)
First Posted : April 24, 2014
Results First Posted : May 22, 2019
Last Update Posted : May 22, 2019
Urology of Virginia
Information provided by (Responsible Party):
University of Southern California

Brief Summary:
The purpose of this clinical study is to evaluate BackStop, a polymer-based device that is intended to be used during ureteroscopic lithotripsy to prevent retrograde stone migration.

Condition or disease Intervention/treatment Phase
Kidney Stones Device: BackStop Not Applicable

Detailed Description:

During ureteroscopic treatment for ureteral stones, lithotripsy, irrigation, and manipulation of the stone often pushes stone away into the kidney itself. This phenomenon is called retropulsion, which is defined as clinically significant retrograde migration of stone or stone fragments. Movement of stones retrograde into the renal pelvis could potentially add and complicate the surgery further. Often scopes need to be changed in order to reach the stone, and chasing these stones will add time to the surgery and require more valuable resources. Furthermore, sometimes a second operation will need to be done when these retropulsed fragments could not be all found and cleaned out.

A number of devices have been developed to prevent such migration including stone baskets and conical devices. These are wire-based devices which have the potential of injuring the ureter. Because of safety concerns and that there is limited data available on the effectiveness of these devices; these are not widely used by urologists. BackStop has recently been developed as another tool to prevent retropulsion. It is a water soluble gel that is injected proximal to the stone. This creates a physical barrier that prevents stone migration during ureteroscopic lithotripsy for ureteral calculus.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 35 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single (Participant)
Primary Purpose: Treatment
Official Title: Post FDA-Approval Clinical Evaluation of BackStopTM in Patients Undergoing Ureteroscopic Lithotripsy: A Prospective, Randomized Clinical Trial
Study Start Date : April 2014
Actual Primary Completion Date : June 2016
Actual Study Completion Date : July 2016

Resource links provided by the National Library of Medicine

Arm Intervention/treatment
Experimental: BackStop
Patients randomized to the Experimental arm will receive the BackStop gel during their ureteroscopic lithotripsy to prevent retrograde migration of stones or stone fragments.
Device: BackStop
BackStop™ is a FDA approved device. It is intended for use during ureteroscopic lithotripsy to prevent retrograde migration of stones and stone fragments. It is comprised of a solution of a thermosensitive polymer, a purified version of poloxamer 407 having been fractionated in saline. BackStop™, which is injected above the stone, is provided in sterile, pre-filled 2.5ml and 5ml syringes along with and a corresponding injector and a catheter (3F or 5F).

No Intervention: Control
Patients randomized to the control group will not use any devices to prevent retrograde migration of stones and stone fragments during their ureteroscopic lithotripsy.

Primary Outcome Measures :
  1. Rate of Prevention of Retrograde Stone or Stone Fragment Migration [ Time Frame: At the time of surgery ]
    Prevention of retrograde stone migration (Yes/No)

Secondary Outcome Measures :
  1. Stone-free Rate [ Time Frame: 2 months ]
    Presence or absence of residual stone fragments at 2 month follow up after lithotripsy

Other Outcome Measures:
  1. Need for Secondary Procedures [ Time Frame: Up to 3 months ]
    Need for secondary procedures of patients who had stone migration

  2. Time for BackStop Injection [ Time Frame: Minutes during Surgery ]
    Time required to deliver BackStop beginning with insertion of BackStop catheter and ending with its removal subsequent to the delivery of BackStop

  3. Duration of Lithotripsy Procedure [ Time Frame: during surgery ]
    Duration of Lithotripsy Procedure

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • patient with solitary ureteral stone ranging from 5mm to 15mm diameter
  • able to tolerate general anesthesia
  • clinical indication for treatment by ureteroscopic lithotripsy
  • must be willing and able to participate in any follow-up visits
  • provide informed consent
  • have a CT scan demonstrating the stone

Exclusion Criteria:

  • patients undergoing extracorporeal shock wave lithotripsy (ESWL) or any other extracorporeal or percutaneous lithotripsy procedure as primary procedure
  • any co-morbidity or condition that would necessitate exclusion of patient (physician opinion)
  • renal or ureteral anatomical abnormality
  • multiple stones in the indicated ureter
  • stones in the indicated kidney
  • patient is immunocompromised
  • multiple organ dysfunction syndrome
  • has an absolute or relative solitary kidney mass
  • >= Stage 3 chronic kidney disease
  • bilateral ureteral obstructing stones
  • staghorn calculi
  • impaction of several stone fragments (Steinstrasse)
  • uncorrected coagulopathy/thrombocytopenia
  • urethral and/or ureteral stricture
  • reconstructive urinary surgery

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT02122341

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United States, California
USC Institute of Urology
Los Angeles, California, United States, 90089
United States, Virginia
Urology of Virginia
Virginia Beach, Virginia, United States, 23462
Sponsors and Collaborators
University of Southern California
Urology of Virginia
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Principal Investigator: Matthew Dunn, M.D. USC Institute of Urology
Additional Information:

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Responsible Party: University of Southern California Identifier: NCT02122341    
Other Study ID Numbers: HS-12-00714
First Posted: April 24, 2014    Key Record Dates
Results First Posted: May 22, 2019
Last Update Posted: May 22, 2019
Last Verified: April 2019
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No
Additional relevant MeSH terms:
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Kidney Calculi
Kidney Diseases
Urologic Diseases
Urinary Calculi
Pathological Conditions, Anatomical