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

A prospective cohort of 40 women aged 18 years or older with urodynamically demonstrated pure stress urinary incontinence or stress-predominant mixed urinary incontinence, without detrusor overactivity. Participants independently choose vaginal laser treatment as routine clinical care before being offered study enrollment. Treatment comprises three non-ablative Er laser sessions (Fotona SP Dynamis Pro; IncontiLase, SMOOTH mode) at 4-6-week intervals. Standardized 4D transperineal ultrasound and clinical assessments are performed before the first session and at 1, 3, and 6 months after the final session.

Within-participant change in craniocaudal urethrovesical junction (UVJ) mobility, measured in millimeters using standardized 4D transperineal ultrasound. UVJ position is measured relative to a horizontal reference line through the posteroinferior margin of the pubic symphysis, with cranial positions coded as negative and caudal positions as positive. Mobility is calculated as UVJ position during maximal Valsalva minus UVJ position at rest. Change is calculated as mobility at 1 month after the final laser session minus baseline mobility. Negative values indicate reduced mobility.

Within-participant change in craniocaudal urethrovesical junction (UVJ) mobility, measured in millimeters using standardized 4D transperineal ultrasound. Mobility is calculated as UVJ position during maximal Valsalva minus UVJ position at rest. Change is follow-up mobility minus baseline mobility, assessed separately at 3 and 6 months. Negative values indicate reduced mobility.

Change in craniocaudal urethrovesical junction position at rest, measured in millimeters using 4D transperineal ultrasound relative to a horizontal line through the posteroinferior margin of the pubic symphysis. Cranial positions are negative and caudal positions positive. Change is follow-up position minus baseline position.

Change in the cross-sectional area of the hypoechoic mid-urethral region at rest, measured in square millimeters by manual tracing on 4D transperineal ultrasound. The measurement plane is perpendicular to the urethral axis at 50% of sonographic urethral length. Change is follow-up area minus baseline area.

Change in the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form (ICIQ-UI SF) total score. Scores range from 0 to 21, with higher scores indicating greater urinary incontinence severity and impact. Change is follow-up score minus baseline score; negative values indicate improvement.

Distribution of responses on the Patient Global Impression of Improvement (PGI-I), a 7-point scale assessing perceived change in urinary incontinence compared with the pretreatment condition. Scores range from 1 (very much better) to 7 (very much worse), with 4 indicating no change. Lower scores indicate greater perceived improvement.