Energy-based therapies for stress urinary incontinence aim to restore urethral support through thermal tissue remodeling and collagen neogenesis in vaginal and periurethral tissues. Radiofrequency devices deliver controlled volumetric heating (40-45°C) via monopolar or bipolar electrodes to the anterior vaginal wall, typically administered in 3-4 monthly sessions of 20-30 minutes each. Fractional CO₂ lasers (wavelength 10,600 nm) and Er:YAG lasers (2,940 nm) create microablative columns penetrating 500-1000 μm depth, triggering controlled wound healing and neo-collagenesis over 2-3 sessions at 4-6 week intervals. High-intensity focused electromagnetic (HIFEM) stimulation induces supra-maximal pelvic floor muscle contractions (>20,000 per session) through electromagnetic fields delivered in 6-8 sessions over 2-4 weeks. Despite increasing clinical adoption and marketing claims, objective evidence using urodynamic parameters to demonstrate physiological changes remains limited. We systematically reviewed studies employing urodynamic testing to objectively assess treatment effects in premenopausal women with stress incontinence.

We searched PubMed, Embase, Cochrane Library, and Cochrane CENTRAL from inception through March 2026 for randomized controlled trials, comparative studies, and prospective cohorts evaluating energy-based treatments (radiofrequency, CO₂ laser, Er:YAG laser, HIFU, electromagnetic stimulation) in premenopausal women with stress urinary incontinence. Inclusion criteria required urodynamic testing both pre- and post-treatment for objective assessment. Primary outcomes included maximum urethral closure pressure (MUCP), Valsalva leak point pressure (VLPP), and urodynamic stress incontinence cure rates (defined as absence of leakage during filling cystometry with provocative maneuvers). Secondary outcomes comprised patient-reported improvement rates and validated symptom scores (ICIQ-UI SF, UDI-6, IIQ-7). Two independent reviewers screened studies, extracted data, and assessed risk of bias using Cochrane Risk of Bias 2.0 tool for randomized trials and ROBINS-I for non-randomized studies.

Six studies involving 687 premenopausal women (mean age 38-44 years, mean BMI 24-27 kg/m²) met inclusion criteria. Baseline urodynamic parameters: mean MUCP 45-55 cmH₂O, mean VLPP 85-105 cmH₂O.
6-Month Outcomes:
Er:YAG laser (2-3 sessions, 10-15 J/cm²): MUCP increased 18-25 cmH₂O, VLPP increased 25-40 cmH₂O, urodynamic cure 55-70%, patient-reported improvement 68-82%.
Radiofrequency (3-4 sessions, 40-45°C): MUCP increased 12-18 cmH₂O, VLPP increased 20-32 cmH₂O, urodynamic cure 45-60%, patient-reported improvement 58-72%.
HIFEM (6-8 sessions): MUCP increased 14-22 cmH₂O, VLPP increased 22-38 cmH₂O, urodynamic cure 50-65%, patient-reported improvement 62-75%.
CO₂ laser (3 sessions, 30-40W): MUCP increased 8-20 cmH₂O, urodynamic cure 35-65%.
12-Month Outcomes (4 studies, n=412): MUCP gains reduced by 40-60%, VLPP improvements decreased by 35-55%, urodynamic cure rates dropped to 25-45%. Patient-reported outcomes showed less decline with 50-60% reporting improvement.
Adverse Events: Transient vaginal discharge (15-25%), mild discomfort (20-35%), no serious complications.

The urodynamic data demonstrate that energy-based interventions produce measurable short-term physiological changes in urethral function, with Er:YAG laser showing consistent objective improvements at 6 months. The magnitude of MUCP and VLPP increases suggests genuine tissue remodeling effects rather than purely placebo responses. However, the substantial deterioration in objective parameters by 12 months raises critical questions about treatment durability and the sustainability of collagen remodeling effects.
The disconnect between declining urodynamic measurements and better-maintained patient-reported outcomes is noteworthy. This discordance may reflect several mechanisms: placebo effects, behavioral adaptations in daily activities, improved pelvic floor muscle awareness and voluntary control, or differences in measurement sensitivity between objective urodynamic testing and subjective symptom reporting.
The heterogeneity in CO₂ laser results likely reflects variations in treatment protocols, energy settings, and tissue penetration depths across studies, highlighting the need for standardized treatment parameters.

Although these intervensions,specially  Er:YAG laser and radiofrequency, represent promising  treatment options for stress urinary incontinence ,  but the lack of urodynamic evidences and inconsistent findings regarding superiority over sham treatment highlight the need for larger, well-designed randomized controlled trials with objective urodynamic assessments to establish definitive clinical efficacy and optimize treatment protocols before widespread clinical adoption.

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