Ureteroscope Diameter Influence Surgeon Stress?
Conditions: Ureteral Stones, Ureteroscopic Lithotripsy
Sponsor: Aydin Adnan Menderes University

Official Title: 
Impact of Ureterorenoscope Diameter on Technical Outcomes, Procedural Difficulty, and 
Surgeon Stress: A Comparative Study 
NCT Number: 
NCT06935500 
Protocol Version: Version 1.0 
Document Date: March 2026 
 
1. Background and Rationale 
Ureterorenoscopy (URS) is widely used in the management of ureteral stones due 
to its high success rates and favorable safety profile. Technological advancements have 
enabled the use of thin-caliber ureteroscopes, which may facilitate atraumatic ureteral 
access and reduce the need for dilation. However, the impact of ureteroscope diameter on 
technical outcomes and surgeon-related factors such as procedural difficulty and 
intraoperative stress remains unclear. 
In addition to traditional surgical outcomes, the psychological burden experienced 
by the surgeon during technically demanding procedures has gained increasing attention. 
Therefore, this study aims to evaluate both technical and surgeon-related outcomes 
associated with different ureteroscope calibers. 
 
2. Objectives 
Primary Objective 
To evaluate the impact of ureterorenoscope diameter on intraoperative surgeon 
stress during ureterorenoscopy. 
Secondary Objectives 

 
To compare technical outcomes between thin-caliber and standard-caliber 
ureteroscopes  
 
To evaluate procedural difficulty  
 
To assess perioperative outcomes including:  
o Stone-free rate (SFR)  
o Ureteral injury (Traxer classification)  
o Balloon dilation requirement  
o JJ stent placement  
o Postoperative complications (Clavien–Dindo classification)  
 
3. Study Design 
This study was designed as a prospective, randomized, single-center clinical 
trial. The study was approved by the local ethics committee (Decision No: 14, Protocol 
No: 
2025/74) 
and 
prospectively 
registered 
at 
ClinicalTrials.gov 
(Identifier: 
NCT06935500). Participants were enrolled between March 2025 and December 2025 and 
randomly assigned in a 1:1 ratio using a simple randomization method. 
 
4. Study Population 
Inclusion Criteria 
 
Patients scheduled for ureterorenoscopy due to ureteral stones  
 
Age ≥18 years  
 
Provision of written informed consent  
Exclusion Criteria 

 
Emergency surgery  
 
Bilateral ureteral stones  
 
Pre-existing double-J stent  
 
Radiolucent stones not adequately evaluated on imaging  
 
5. Interventions 
Participants were randomized into two groups: 
 
Group 1: 4.5–6.5 Fr semirigid ureteroscope (thin-caliber)  
 
Group 2: 8–9.8 Fr semirigid ureteroscope (standard-caliber)  
All procedures were performed under spinal anesthesia using a holmium:YAG laser 
system. Ureteral dilation and JJ stent placement were performed when clinically 
indicated. 
 
6. Outcome Measures 
Primary Outcome 
 
Occurrence of stress-related procedures (defined as ΔSTAI-TX1 > 0)  
Secondary Outcomes 
 
Stone-free rate at 1 month  
 
Operative time  
 
Balloon dilation requirement  
 
Ureteral injury (Traxer classification)  
 
JJ stent placement  

 
Postoperative complications (Clavien–Dindo classification)  
 
7. Assessment of Surgeon Stress 
Surgeon stress was assessed using the State–Trait Anxiety Inventory (STAI-
TX1). The 20-item state anxiety scale was administered immediately before and after 
each procedure by an independent investigator. An increase in postoperative STAI-TX1 
score compared to preoperative score (ΔSTAI-TX1 > 0) was defined as a stress-related 
procedure. 
 
8. Data Collection 
Collected variables included: 
 
Demographics (age, sex, BMI)  
 
Stone characteristics (size, location, side)  
 
Operative time  
 
Perioperative outcomes  
 
STAI-TX1 scores  
 
9. Statistical Analysis (SAP) 
Statistical analyses were performed using SPSS (version 20.0; IBM, Armonk, NY). 
 
Continuous variables: Student’s t-test or Mann–Whitney U test  
 
Categorical variables: Chi-square or Fisher’s Exact test  
 
Significance level: p < 0.05  

Sample size was calculated using G*Power (v3.1). Based on prior SFR data, 65 
patients per group were required (power 95%, alpha 0.05). Multivariable logistic 
regression analysis was performed to identify independent predictors of stress-related 
procedures. 
Variables included: 
 
Ureteroscope caliber  
 
Stone size  
 
Stone location  
 
Operative time  
Adjusted odds ratios (aOR) with 95% confidence intervals were calculated. Model 
calibration was assessed using the Hosmer–Lemeshow test. 
 
10. Ethics 
The study was approved by the Aydın Adnan Menderes University Ethics Committee 
(Decision No: 14, Protocol No: 2025/74). All participants provided written informed 
consent. The study was conducted in accordance with the Declaration of Helsinki. 
 
11. Protocol Amendments 
No protocol amendments were made prior to submission.