A Prospective Analysis of Thulium Fiber Laser Efficiency

May 5, 2026 updated by: Volkan Selmi, Bozok University

A Prospective Analysis of Thulium Fiber Laser Efficiency: How Stone Volume and Density Predict Intraoperative Energy Consumption

Patients diagnosed with urolithiasis will be prospectively enrolled in this study. Preoperative diagnostic assessment will be performed using computed tomography (CT). Key parameters, including stone dimensions, quantity, total stone burden, and stone density (Hounsfield units), will be evaluated preoperatively. This study aims to analyze data from patients who undergo ureteroscopic Thulium Fiber Laser (TFL) lithotripsy and achieve a stone-free status within a single procedural session. Based on these data, a 'Specific Energy Coefficient' will be derived to enable the preoperative prediction of the total laser energy required for successful lithotripsy.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

This prospective observational trial investigated the correlation between Thulium Fiber Laser (TFL) energy consumption and stone characteristics. Adult patients (≥18 years) with symptomatic urinary stones indicated for (f)URS and normal upper tract anatomy were included. Only patients achieving a complete stone-free status in a single session were analyzed. Exclusion criteria comprised active urinary tract infection, history of ipsilateral surgery or stent placement within six months, congenital renal anomalies, and postoperative residual fragments. Stone parameters were evaluated via non-contrast computed tomography (NCCT, 1.0 mm slice thickness). Mean stone density was measured in Hounsfield Units (HU) using a representative region of interest (ROI). Stone volume (V) was calculated using the validated ellipsoid formula. Procedures were performed by two high-volume endourologists using a 200 µm Thulium fiber. Semirigid URS (7.5-9.5 F) or flexible URS (7.5 F) with an access sheath (10/12-12/14 F) were utilized based on stone location. All cases employed "Dusting Mode" (0.1-0.2 J; 80-150 Hz). Laser ablation time was recorded from the initial firing until complete visual stone clearance/dusting. The primary outcome was the derivation of the Specific Energy Coefficient, calculated by dividing the total energy by the product of stone volume and density. Data were analyzed using SPSS v26.0. Normality was assessed via Shapiro-Wilk/Kolmogorov-Smirnov tests. Descriptive data were reported as mean ± standard deviation or median. Spearman's correlation and Multiple Linear Regression were used to identify independent predictors of laser energy requirements, with the model's predictive power reported as adjusted R2. Statistical significance was set at p < 0.05.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
61

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Turkey (Türkiye)
    • Yozgat
      • Yozgat, Yozgat, Turkey (Türkiye), 66100
        • Yozgat Bozok University Faculty of Medicine

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • aged 18 years and above
  • diagnosed with symptomatic urinary system stones
  • planned URS or fURS
  • normal upper urinary tract anatomy
  • achieved stone-free

Exclusion Criteria:

  • active urinary tract infection
  • history of surgery/DJ stent placement within the last six months
  • congenital renal anomalies
  • patients with residual fragments on postoperative evaluation

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Stone-free
Procedure: thulium fiber laser lithotripsy
Procedures were performed by two high-volume experienced endourologists. Semirigid URS (7.5-9.5 F) was utilized for ureteral stones, while flexible URS (7.5 F) with a ureteral access sheath (10/12 F or 12/14 F) was preferred for renal stones. A 200 µm Thulium fiber was employed in all cases. Fragmentation was performed in Dusting Mode (Pulse Energy: 0.1-0.2 J, Frequency: 80-150 Hz).

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Time Frame
thulium fiber laser energy consumption per mm3xHu
Time Frame: 4 weeks
4 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Bozok University

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: volkan selmi, Yozgat Bozok University

Publications and helpful links

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General Publications

Study record dates

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Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 1, 2025

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
January 31, 2026

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
January 31, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
April 28, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 28, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
May 5, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 8, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 5, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2025-GOKAEK-2513

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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