Clinical Trial Evaluating the Efficiency of Holmium Laser Settings on Urinary Stones

Status:Enrolling by invitation
Conditions:Nephrology, Nephrology, Nephrology
Therapuetic Areas:Nephrology / Urology
Age Range:18 - Any
Start Date:July 1, 2019
End Date:October 31, 2023

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The primary objective of this study is to compare the time to acceptable stone fragmentation
during clinical use of the holmium laser when using energy settings 0.2J vs 0.8J. The
hypothesis is that holmium laser energy settings 0.8J will require less time than lower
energy settings 0.2J for fragmenting urinary stones. The clinical practice is to treat
urinary stones until the stone is reduced to fragments ≤ 2 mm in size. This is determined by
using the laser fiber which is 273 microns to visually estimate the size of the resultant
fragments as described by Patel et al, J Endo 2014. Investigators will standardize the effect
of stone size by creating a ratio of stone size to treatment time. In this study, the
frequency is set at 15Hz. Thus, the study contains two arms: 0.2J&15Hz, and 0.8J&15Hz.
Patients will be randomized into the two groups by the ratio of 1:1.

The only interventions imposed on subjects as a result of this study are (1.) pre-procedural
randomization to laser lithotripsy with either 0.2J or 0.8J energy setting, and (2.) the use
of patient information in describing results. All the other activities are part of the
routine clinical practice in the department. Participation in the study will not alter the
patients' preoperative, or postoperative care. During surgery, patients' stones will be
treated in accordance with the routine clinical practice of fragmenting stones into small
pieces (<2 mm). All patients enrolled will undergo routine post-operative follow up including
clinic appointments and imaging evaluation. Any complications will be recorded, reported, and
treated appropriately. A fixed frequency will be used (15Hz). Thus, the study contains two
arms: 0.2J&15Hz, and 0.8J&15Hz. Patients will be randomized into the two groups by the ratio
of 1:1. A total of 1 clinic visit (i.e., the stone surgery, approximately 5-6 hours,
depending on the duration of the surgery) is needed for this study.

The study procedures are:

1. A study team member who is affiliated with the patient's clinical care (e.g., the
surgeon) will initially approach the patients who are scheduled laser lithotripsy
treatment of urinary stones. (i.e. informed that there's a research study they may be
eligible for, and asked if they want to learn more about it).

2. If the patient is interested in the study, a member of the research team will approach
him/her for enrollment.

3. Once the consent form is obtained, patients' medical background will be reviewed for
inclusion/exclusion criteria. Patients who meet the inclusion criteria will be included
in the study; patients who do not meet the inclusion criteria will be excluded.

4. Patients will be randomized to either 0.2J&15Hz or 0.8J&15Hz (randomization ratio 1:1)

5. Patients will undergo stone surgeries with the laser setting that they are randomized
to. The patient's stone(s) will be treated in accordance with the routine clinical
practice of fragmenting stone into small pieces (≤ 2mm). The faculty surgeon (i.e., Dr.
Nakada) will perform all surgeries.

6. Fragmentation time as well as other information (total surgery time, complications,
stone information, and number of stones treated) is collected.

7. After surgery, the patients will then continue on normal postoperative pathway.
Postoperative complications will be collected.

Inclusion Criteria:

- Patients at least 18 years of age

- Patients with urinary stones who require endoscopic treatment

Exclusion Criteria:

- Patients < 18 years of age

- Pregnant patients

- Pre-menopausal females who have not been on approved birth control for at least 1
month pre-operatively

- Patients with stones known to be refractory to treatment with the holmium laser
We found this trial at
Madison, Wisconsin 53792
(608) 263-2400
Principal Investigator: Stephen Nakada, MD
Phone: 608-265-6460
University of Wisconsin In achievement and prestige, the University of Wisconsin–Madison has long been recognized...
Madison, WI
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