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

Completed

Conditions

Intervention / Treatment

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

Interventional

Enrollment (Actual)

61

Phase

  • 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

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
Intervention / Treatment
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

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

Bozok University

Investigators

  • Principal Investigator: volkan selmi, Yozgat Bozok University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

June 1, 2025

Primary Completion (Actual)

January 31, 2026

Study Completion (Actual)

January 31, 2026

Study Registration Dates

First Submitted

April 28, 2026

First Submitted That Met QC Criteria

April 28, 2026

First Posted (Actual)

May 5, 2026

Study Record Updates

Last Update Posted (Actual)

May 8, 2026

Last Update Submitted That Met QC Criteria

May 5, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID 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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