Second-generation Radiofrequency Application and Specific Therapeutic Exercise as a Treatment for Stress Urinary Incontinence Due to Urethral Instability. Randomised Clinical Trial
Phase: NA
Conditions: Stress Urinary Incontinence
Sponsor: Cardenal Herrera University

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
GENERAL STUDY INFORMATION AND INFORMED CONSENT 
UNIVERSITY CEU CARDENAL HERRERA 
Principal investigator: Dr. Sergio Montero Navarro 
 
TITLE: Second-generation Radiofrequency Application and Specific Therapeutic 
Exercise as a Treatment for Stress Urinary Incontinence Due to Urethral 
Instability. Randomised Clinical Trial 
 
 
Research and Ethics Committee of CARDENAL HERRERA CEU UNIVERSITY: 
CEEI25/646 
 
NCT ID: 
 
DATE: 01-14-2026 

 
 
GENERAL STUDY INFORMATION 
 
TITLE: Second-generation Radiofrequency Application and Specific 
Therapeutic Exercise as a Treatment for Stress Urinary Incontinence 
Due to Urethral Instability. Randomised Clinical Trial 
 
 
Mr. Sergio Montero Navarro, Physiotherapist, principal investigator and researcher reports 
that: 
 
The tests performed are simple and in no case involve difficulty, fatigue, danger, injury, 
pain or adverse reaction. 
 
They will be carried out by collegiate physiotherapists in the School of Physiotherapists of 
the Valencian Community. 
 
The general data of the subject will be collected (name, age, sex, physical variables and 
clinical history). The article must be sent with comfortable clothes The day that sea cited by 
the researcher, previous notice. Personal data is recognized in this study. 
 
The personal data are confidential, apply to the protection of personal data (Organic Law 
15/1999, December 13) and any other thing that may be applicable. 
 
This study was approved by the Research and Ethics Committee of CARDENAL 
HERRERA CEU UNIVERSITY: CEEI25/646 

 
 
 
 
INFORMED CONSENT 
 
Mr/Mrs ................................................................................................... with Number 
identification ........................................... freely and voluntarily, I DECLARE: 
 
That I have read the information contained in this document about the general information 
of the study. 
 
I have been informed that all tests are simple to perform and do not produce harmful effects 
on health. They will be carried out in appropriate facilities and will be carried out by 
qualified and specialized personnel. 
 
I have also been informed that, the data collected in this study will be treated confidentially, 
applying the current legislation on protection of personal data (Organic Law 15/1999, of 
December 13) and any other applicable. 
 
Therefore, I give my consent and I authorize Mr. Sergio Montero Navarro, to carry out the 
detailed study in this document with the help of the necessary personnel with the 
appropriate qualification and specialization. 
 
In Elche, to ...... of ............................................ of 202 
 
SIGNED: 

 
 
 
 
 
 
 
 
 
 
 
 
 
STUDY PROTOCOL PLAN AND STADISTICAL ANALYSIS PLAN (SAP) 
UNIVERSITY CEU CARDENAL HERRERA 
Principal investigator: Dr. Sergio Montero Navarro 
 
TITLE: Second-generation Radiofrequency Application and Specific Therapeutic 
Exercise as a Treatment for Stress Urinary Incontinence Due to Urethral 
Instability. Randomised Clinical Trial 
 
 
Research and Ethics Committee of CARDENAL HERRERA CEU UNIVERSITY: 
CEEI25/646 
 
NCT ID: 
 
DATE: 01-14-2026 

 
STUDY PROTOCOL PLAN 
 
 
Objectives: 
The objectives of our study have been the following: 
 
The purpose of this study is to evaluate the correlation between urethral instability, 
assessed by ultrasound analysis of the bladder neck opening, and the severity of SUI, 
assessed by validated standard questionnaires. The determination of standard ultrasound 
parameters that allow urethral instability to be related to the severity of SUI would be a 
valuable finding for accurately diagnosing the severity of SUI using low-cost, easy-to-use 
imaging methods. 
 
A randomized, single-blind clinical trial will be conducted in women with stress urinary 
incontinence (SUI). Participants will be randomly assigned to one of three intervention groups: 
radiofrequency (RF), specific pelvic floor muscle exercise (PFMT), or combined treatment 
(RF + PFMT). The study will be carried out at Clínica Traña (San José, Costa Rica), with an 
expected start date in 2025. The study will adhere to the principles of the Declaration of 
Helsinki and current European data protection regulations. 
Adult women with urinary leakage and a bladder neck opening greater than 90°, assessed by 
functional ultrasound, will be included. Women with other pelvic floor disorders, pregnancy, 
recent treatments (RF, PFME, hormonal or laser therapies), relevant neurological, metabolic, 
or cardiovascular conditions, prior pelvic surgery, active infections, or contraindications to the 
interventions will be excluded. The estimated sample size is 117 participants (39 per group), 
calculated to detect statistically significant differences with 80% power and a 5% significance 
level, allowing for a 30% dropout rate. 
Before the intervention, all participants will undergo physical examination, digital palpation, 
and functional pelvic floor ultrasound, as well as complete validated questionnaires assessing 
urinary incontinence severity and quality of life (ICIQ-SF, King’s Health Questionnaire, and 
Sandvik Severity Index). These assessments will be repeated at the end of the intervention and 
at 15 days, 3 months, 6 months, and 12 months post-intervention. 
Randomization will be performed using statistical software, and outcome assessors will remain 
blinded to group allocation. Data will be coded and securely stored, ensuring participant 
confidentiality in accordance with the General Data Protection Regulation (EU 2016/679). 

 
The RF intervention will consist of five weekly sessions of non-ablative fractional vaginal 
radiofrequency with temperature control and standardized parameters. The PFME program 
will comprise a structured core and pelvic floor exercise protocol supervised by 
physiotherapists, conducted twice weekly over a 16-week period. The combined group will 
receive both interventions. 
Primary outcomes will include pelvic floor muscle strength and function (Oxford scale, 
endurance, and fatigability), ultrasound parameters (bladder neck opening, urethral 
hypermobility, and presence of prolapse), and validated questionnaires assessing urinary 
incontinence severity and quality of life. 

 
 

 
Statistical Analysis Plan (SAP) 
 
 
Data will be expressed as mean ± standard deviation or as a percentage. The 
distribution of the sample will be determined using the Kolmogorov-Smirnov test. For 
quantitative variables, depending on the type of variable, Student's t-test or Mann- 
Whitney U test will be performed. The correlation between variables will be analyzed 
using Spearman's correlation. In the case of qualitative variables, the association 
between variables will be analyzed using bivariate or multivariate logistic regression, as 
appropriate, and contingency tables. The statistical significance of the difference 
between them will be evaluated using Pearson's χ2 test. Statistical significance will be 
assumed with p-values <0.05. 
 
To evaluate the diagnostic capacity of bladder neck opening measured by ultrasound 
analysis in the classification of the severity of stress urinary incontinence, a logistic 
regression analysis was performed. The dichotomized severity of the Sandvick test 
(mild/moderate versus severe/very severe) will be taken as the gold standard. 
Demographic and clinical variables will be evaluated as possible covariates and 
included in subsequent models if they had a p-value < 0.200. 
 
Sensitivity, specificity, Youden's index (sensitivity + specificity − 1), and positive and 
negative likelihood ratios (LR+ and LR−) will be calculated for bladder neck opening at 
rest, during the Vasalva maneuver, the variation between the two, and for the 
maximum model with the three variables. 
 
The optimal cutoff point for bladder neck opening at rest will be determined using the 
Youden index. Subsequently, this value will be transformed into clinical units (mm) by 
algebraic solving of the logistic model equation, adjusted for relevant covariates (age 
and BMI). This approach preserves the statistical fit of the model while providing a 
clinically interpretable threshold. 
 
Studentized residuals, leverage values, and Cook's distances will be estimated to 
identify possible outliers and influential values in the dependent variable, the predictors, 
and the model as a whole. 
 
Receiver operating characteristic (ROC) curves will be constructed to determine the 
area under the curve (AUC). Likewise, the Hosmer-Lemeshow goodness-of-fit test will 
be applied to compare the observed and expected frequencies of the model 
(considering p > 0.05 as an adequate fit). The accuracy of the probabilistic predictions 
will be evaluated using the Brier Score (lower values indicate better performance). The 

 
analysis will be performed using SPSS Statistics 29.0 (IBM Corp.)