Kidney Stones
Conditions
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.
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.
Interventions
DEVICEBackStop
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).
Sponsors
Urology of Virginia
University of Southern California
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Rate of Prevention of Retrograde Stone or Stone Fragment Migration | At the time of surgery | Prevention of retrograde stone migration (Yes/No) |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Stone-free Rate | 2 months | Presence or absence of residual stone fragments at 2 month follow up after lithotripsy |
Other
| Measure | Time frame | Description |
|---|---|---|
| Need for Secondary Procedures | Up to 3 months | Need for secondary procedures of patients who had stone migration |
| Time for BackStop Injection | 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 |
| Duration of Lithotripsy Procedure | during surgery | Duration of Lithotripsy Procedure |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| 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.
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). | 17 |
| 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. | 18 |
| Total | 35 |
Baseline characteristics
| Characteristic | Experimental: Backstop | No Intervention: Control | Total |
|---|---|---|---|
| Age, Categorical <=18 years | 0 Participants | 0 Participants | 0 Participants |
| Age, Categorical >=65 years | 2 Participants | 6 Participants | 8 Participants |
| Age, Categorical Between 18 and 65 years | 15 Participants | 12 Participants | 27 Participants |
| Ethnicity (NIH/OMB) Hispanic or Latino | 4 Participants | 5 Participants | 9 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 12 Participants | 12 Participants | 24 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 1 Participants | 1 Participants | 2 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Asian | 2 Participants | 1 Participants | 3 Participants |
| Race (NIH/OMB) Black or African American | 4 Participants | 1 Participants | 5 Participants |
| Race (NIH/OMB) More than one race | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 4 Participants | 5 Participants | 9 Participants |
| Race (NIH/OMB) White | 7 Participants | 11 Participants | 18 Participants |
| Region of Enrollment United States | 17 participants | 18 participants | 35 participants |
| Sex: Female, Male Female | 8 Participants | 5 Participants | 13 Participants |
| Sex: Female, Male Male | 9 Participants | 13 Participants | 22 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — |
| other Total, other adverse events | 4 / 17 | 0 / 18 |
| serious Total, serious adverse events | 0 / 17 | 0 / 18 |
Outcome results
Primary
Rate of Prevention of Retrograde Stone or Stone Fragment Migration
Prevention of retrograde stone migration (Yes/No)
Time frame: At the time of surgery
| Arm | Measure | Category | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| Investigational: BackStop | Rate of Prevention of Retrograde Stone or Stone Fragment Migration | Yes | 14 Participants |
| Investigational: BackStop | Rate of Prevention of Retrograde Stone or Stone Fragment Migration | No | 3 Participants |
| No Intervention: Control | Rate of Prevention of Retrograde Stone or Stone Fragment Migration | Yes | 11 Participants |
| No Intervention: Control | Rate of Prevention of Retrograde Stone or Stone Fragment Migration | No | 7 Participants |
Secondary
Stone-free Rate
Presence or absence of residual stone fragments at 2 month follow up after lithotripsy
Time frame: 2 months
Population: Number of patients analyzed is inconsistent with numbers provided in participant flow module due to patients lost to follow up
| Arm | Measure | Category | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| Investigational: BackStop | Stone-free Rate | Present | 9 Participants |
| Investigational: BackStop | Stone-free Rate | Absent | 0 Participants |
| No Intervention: Control | Stone-free Rate | Present | 10 Participants |
| No Intervention: Control | Stone-free Rate | Absent | 0 Participants |
Other Pre-specified
Duration of Lithotripsy Procedure
Duration of Lithotripsy Procedure
Time frame: during surgery
| Arm | Measure | Value (MEAN) |
|---|---|---|
| Investigational: BackStop | Duration of Lithotripsy Procedure | 4.17 minutes |
| No Intervention: Control | Duration of Lithotripsy Procedure | 6.09 minutes |
Other Pre-specified
Need for Secondary Procedures
Need for secondary procedures of patients who had stone migration
Time frame: Up to 3 months
| Arm | Measure | Category | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| Investigational: BackStop | Need for Secondary Procedures | Yes | 0 Participants |
| Investigational: BackStop | Need for Secondary Procedures | No | 3 Participants |
| No Intervention: Control | Need for Secondary Procedures | Yes | 0 Participants |
| No Intervention: Control | Need for Secondary Procedures | No | 7 Participants |
Other Pre-specified
Time for BackStop Injection
Time required to deliver BackStop beginning with insertion of BackStop catheter and ending with its removal subsequent to the delivery of BackStop
Time frame: Minutes during Surgery
Population: The control group did not receive BackStop injection
| Arm | Measure | Value (MEAN) |
|---|---|---|
| Investigational: BackStop | Time for BackStop Injection | 3.04 minutes |