Standardized 4D Transperineal Ultrasound Assessment of Urethrovesical Junction Mobility After Vaginal Laser Treatment for Stress Urinary Incontinence.

This prospective single-center observational cohort study will assess changes in urethrovesical junction (UVJ) mobility and urethral morphology after vaginal Er:YAG laser treatment in 40 adult women with pure stress urinary incontinence (SUI) or stress-predominant mixed urinary incontinence. Participants will independently choose self-paid laser treatment as routine clinical care before being offered study participation. Treatment comprises three sessions at 4-6-week intervals. Standardized 4D transperineal ultrasound and clinical assessments will be performed at baseline and 1, 3, and 6 months after the final session. The primary outcome is change in craniocaudal UVJ mobility, measured in millimeters, from baseline to 1 month after the final session. Secondary outcomes include UVJ mobility at 3 and 6 months, UVJ position, mid-urethral morphology, patient-reported outcomes, cough stress test results, adverse events, and initiation of additional SUI treatment. Exploratory analyses will assess associations between ultrasound changes and clinical outcomes.

Inclusion Criteria: * Female sex. * Age 18 years or older. * Pure stress urinary incontinence or stress-predominant mixed urinary incontinence. In women with mixed urinary incontinence, the stress component must be the dominant and most bothersome symptom. * Urodynamically demonstrated stress urinary incontinence. * Absence of detrusor overactivity on urodynamic testing. * Independent decision to undergo self-paid vaginal laser treatment as routine clinical care, made before the offer of study participation. * Ability to complete the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form (ICIQ-UI SF). * Ability to perform a technically acceptable Valsalva maneuver. * Willingness to attend the scheduled follow-up visits. * Written informed consent to study participation. Exclusion Criteria: * Predominant overactive bladder or predominant urgency urinary incontinence. * Previous surgery for stress urinary incontinence. * Previous vaginal laser treatment. * Previous pelvic organ prolapse surgery. * Pelvic Organ Prolapse Quantification (POP-Q) stage II or greater in any compartment. * Current pessary use at enrollment. * Active pelvic floor physiotherapy at enrollment. * Previous pelvic radiotherapy. * Pregnancy. * Unexplained genital bleeding. * Pelvic malignancy. * Any other contraindication to vaginal laser treatment. * Active urinary tract or vaginal infection. Enrollment and laser treatment will be deferred until the infection has resolved.