A preclinical study of nonsurgical radiofrequency collagen remodeling for the treatment of stress urinary incontinence

Clinical utility of radiofrequency energy for female genitourinary dysfunction: past, present, and future

INTRODUCTION AND HYPOTHESIS

Radiofrequency (RF) energy has been delivered in a variety of methods to the vagina, bladder, and periurethral tissue to improve myriad genitourinary complaints. Currently, practitioners are promoting transvaginal RF treatments with a minimal understanding of the various platforms and data to support or refute their utilization. This review explores how various RF technologies create desired tissue effects, review the published literature reporting outcomes of various treatment regimes, and peer into potential future uses of this technology in urogynecology.

METHODS

A comprehensive literature review was performed for articles pertaining to RF energy use in women for genitourinary complaints with regard to stress urinary incontinence (SUI), genitourinary syndrome of menopause (GSM), female sexual dysfunction (FSD), and overactive bladder (OAB).

RESULTS

Radiofrequency energy devices heat tissues via direct or micro-needling applications with the goal of stimulating collagen remodeling, neovascularization, and potentially modulation of nerve function. By altering the approach and location of energy application, many new devices have been marketed for treatment of conditions such as SUI, GSM, FSD, and OAB. Available studies demonstrate promising efficacy and favorable safety; however, interpretation of studies is greatly limited by poor study quality and reporting.

CONCLUSIONS

Despite a lack of high-quality evidence for efficacy, safety, and durability in the literature, practitioners around the world continue to promote RF technology for a variety of genitourinary complaints. Currently, it appears that RF energy can potentially treat a variety of genitourinary conditions, but more robust data are needed to substantiate evidence-based use.

[Effectiveness of multimodal rehabilitation (biofeedback plus capacitive-resistive radiofrequency) on chronic pelvic pain and dyspareunia: prospective study and literature review]

OBJECTIVE

To determine whether a multimodal rehabilitation protocol (Biofeedback [BFB] plus capacitive-resistive [INDIBA®] radiofrequency [RF]) reduces pain and increases muscular strength in patients with chronic pelvic pain (CPP) and dyspareunia.

MATERIAL AND METHODS

We performed a prospective, quasi-experimental, before-after study in 37 patients with CPP and/or dyspareunia referred to the Rehabilitation Department of Hospital Universitario Santa Cristina (January 2016 to December 2018). The protocol consisted of 8 sessions of pelvic floor exercises assisted by manometric BFB (15min of tonic/phasic exercises each) supervised by a physiotherapist, followed by suprapubic and perineovaginal bipolar RF [capacitive(5 min)/resistive(10 min)]. The variables evaluated were pain (VAS 0-10) and strength (mmHg) of the pelvic floor musculature and the start/end of the treatment.

RESULTS

The mean age was 41.5±12.65 years. The prevalence was higher among women aged 21-40 years (n=20, 54%) and those aged 41-60 years (n=12; 32.4%). Dyspareunia was present in 34 patients (91.8%), and non-specific CPP in 3 (8.2%). The protocol improved pain (from 7.27±1.34 to 3.75±2.21 points), maximal muscular strength (from 25.56±15.9mmHg to 35.35±20.4mmHg) and mean muscular strength (from 4.86±3.53mmHg to 7.18±4.46mmHg) respectively (p<0.0001).

CONCLUSION

CPP and dyspareunia are a diagnostic challenge that requires multidisciplinary management. Treatment should be started early and should consist of distinct therapeutic modalities. The protocol of multimodal rehabilitation including BFB and capacitive-resistive RF reduces pain and improves strength in patients with CPP and dyspareunia.

Dual-sectored transurethral ultrasound for thermal treatment of stress urinary incontinence: in silico studies in 3D anatomical models

The purpose of this study is to investigate the feasibility and performance of a stationary, non-focused dual-sectored tubular transurethral ultrasound applicator for thermal exposure of tissue regions adjacent to the urethra for treatment of stress urinary incontinence (SUI) through acoustic and biothermal simulations on 3D anatomical models. Parametric studies in a generalized tissue model over dual-sectored ultrasound applicator configurations (acoustic surface intensities, lateral active acoustic output sector angles, and durations) were performed. Selected configurations and delivery strategies were applied on 3D pelvic anatomical models. Temperature and thermal dose distributions on the target region and surrounding tissues were calculated. Endovaginal cooling was explored as a strategy to mitigate vaginal heating. The 75-90° dual-sectored transurethral tubular transducer (3.5 mm outer diameter (OD), 14 mm length, 6.5 MHz, 8.8-10.2 W/cm²) and 2-3-min sonication duration were selected from the parametric study for acoustic and biothermal simulations on anatomical models. The transurethral applicator with two opposing 75-90° active lateral tubular sectors can create two heated volumes for a total of up to 1.8 cm³ over 60 EM_43 °C, with at least 10 mm radial penetration depth, 1.2 mm urethral sparing, and no lethal damage to the vagina and adjacent bone (< 60 EM_43 °C). Endovaginal cooling can be applied to further reduce the vaginal wall exposure (< 15 EM_43 °C). Simulations on 3D anatomical models indicate that dual-sectored transurethral ultrasound applicators can selectively heat pelvic floor tissue lateral to the mid-urethra in short treatment durations, without damaging adjacent vaginal and bone tissues, as a potential alternative treatment option for stress urinary incontinence. Graphical abstract Schema for in silico investigation of transurethral ultrasound thermal therapy applicator for minimally invasive treatment of SUI.

Transurethral high-intensity ultrasound for treatment of stress urinary incontinence (SUI): simulation studies with patient-specific models

BACKGROUND

Stress urinary incontinence (SUI) is prevalent in adult women, attributed to weakened endopelvic supporting tissues, and typically treated using drugs and invasive surgical procedures. The objective of this in silico study is to explore transurethral high-intensity ultrasound for delivery of precise thermal therapy to the endopelvic tissues adjacent to the mid-urethra, to induce thermal remodeling as a potential minimally invasive treatment alternative.

METHODS

3D acoustic (Rayleigh-Sommerfeld) and biothermal (Pennes bioheat) models of the ultrasound applicator and surrounding tissues were devised. Parametric studies over transducer configuration [frequency, radius-of-curvature (ROC)] and treatment settings (power, duration) were performed, and select cases on patient-specific models were used for further evaluation. Transient temperature and thermal dose distributions were calculated, and temperature and dose metrics reported.

RESULTS

Configurations using a 5-MHz curvilinear transducer (3.5 × 10 mm, 28 mm ROC) with single 90 s sonication can create heated zones with 11 mm penetration (>50 °C) while sparing the inner 1.8 mm (<45 °C) radial depth of the urethral mucosa. Sequential and discrete applicator rotations can sweep out bilateral coagulation volumes (1.4 W power, 15° rotations, 600 s total time), produce large volumetric (1124 mm³ above 60 EM43 °C) and wide angular (∼50.5° per lateral sweep) coverage, with up to 15.6 mm thermal penetration and at least 1.6 mm radial urethral protection (<5 EM43 °C).

CONCLUSION

Transurethral applicators with curvilinear ultrasound transducers can deliver spatially selective temperature elevations to lateral mid-urethral targets as a possible means to tighten the endopelvic fascia and adjacent tissues.

Optical clearing of vaginal tissues, ex vivo, for minimally invasive laser treatment of female stress urinary incontinence

Near-infrared laser energy in conjunction with applied tissue cooling is being investigated for thermal remodeling of the endopelvic fascia during minimally invasive treatment of female stress urinary incontinence. Previous computer simulations of light transport, heat transfer, and tissue thermal damage have shown that a transvaginal approach is more feasible than a transurethral approach. However, results were suboptimal, and some undesirable thermal insult to the vaginal wall was still predicted. This study uses experiments and computer simulations to explore whether application of an optical clearing agent (OCA) can further improve optical penetration depth and completely preserve the vaginal wall during subsurface treatment of the endopelvic fascia. Several different mixtures of OCA’s were tested, and 100% glycerol was found to be the optimal agent. Optical transmission studies, optical coherence tomography, reflection spectroscopy, and computer simulations [including Monte Carlo (MC) light transport, heat transfer, and Arrhenius integral model of thermal damage] using glycerol were performed. The OCA produced a 61% increase in optical transmission through porcine vaginal wall at 37°C after 30 min. The MC model showed improved energy deposition in endopelvic fascia using glycerol. Without OCA, 62%, 37%, and 1% of energy was deposited in vaginal wall, endopelvic fascia, and urethral wall, respectively, compared with 50%, 49%, and 1% using OCA. Use of OCA also resulted in 0.5-mm increase in treatment depth, allowing potential thermal tissue remodeling at a depth of 3 mm with complete preservation of the vaginal wall.

Transurethral radiofrequency collagen denaturation for the treatment of women with urinary incontinence

BACKGROUND

Transurethral radiofrequency collagen denaturation is a relatively novel, minimally invasive device-based intervention used to treat individuals with urinary incontinence (UI). No systematic review of the evidence supporting its use has been published to date.

OBJECTIVES

To evaluate the efficacy of transurethral radiofrequency collagen denaturation, compared with other interventions, in the treatment of women with UI.Review authors sought to compare the following.• Transurethral radiofrequency collagen denaturation versus no treatment/sham treatment.• Transurethral radiofrequency collagen denaturation versus conservative physical treatment.• Transurethral radiofrequency collagen denaturation versus mechanical devices (pessaries for UI).• Transurethral radiofrequency collagen denaturation versus drug treatment.• Transurethral radiofrequency collagen denaturation versus injectable treatment for UI.• Transurethral radiofrequency collagen denaturation versus other surgery for UI.

SEARCH METHODS

We conducted a systematic search of the Cochrane Incontinence Group Specialised Register (searched 19 December 2014), EMBASE and EMBASE Classic (January 1947 to 2014 Week 50), Google Scholar and three trials registries in December 2014, along with reference checking. We sought to identify unpublished studies by handsearching abstracts of major gynaecology and urology meetings, and by contacting experts in the field and the device manufacturer.

SELECTION CRITERIA

Randomised and quasi-randomised trials of transurethral radiofrequency collagen denaturation versus no treatment/sham treatment, conservative physical treatment, mechanical devices, drug treatment, injectable treatment for UI or other surgery for UI in women were eligible.

DATA COLLECTION AND ANALYSIS

We screened search results and selected eligible studies for inclusion. We assessed risk of bias and analysed dichotomous variables as risk ratios (RRs) with 95% confidence intervals (CIs) and continuous variables as mean differences (MDs) with 95% CIs. We rated the quality of evidence using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach.

MAIN RESULTS

We included in the analysis one small sham-controlled randomised trial of 173 women performed in the United States. Participants enrolled in this study had been diagnosed with stress UI and were randomly assigned to transurethral radiofrequency collagen denaturation (treatment) or a sham surgery using a non-functioning catheter (no treatment). Mean age of participants in the 12-month multi-centre trial was 50 years (range 22 to 76 years).Of three patient-important primary outcomes selected for this systematic review, the number of women reporting UI symptoms after intervention was not reported. No serious adverse events were reported for the transurethral radiofrequency collagen denaturation arm or the sham treatment arm during the 12-month trial. Owing to high risk of bias and imprecision, we downgraded the quality of evidence for this outcome to low. The effect of transurethral radiofrequency collagen denaturation on the number of women with an incontinence quality of life (I-QOL) score improvement ≥ 10 points at 12 months was as follows: RR 1.11, 95% CI 0.77 to 1.62; participants = 142, but the confidence interval was wide. For this outcome, the quality of evidence was also low as the result of high risk of bias and imprecision.We found no evidence on the number of women undergoing repeat continence surgery. The risk of other adverse events (pain/dysuria (RR 5.73, 95% CI 0.75 to 43.70; participants = 173); new detrusor overactivity (RR 1.36, 95% CI 0.63 to 2.93; participants = 173); and urinary tract infection (RR 0.95, 95% CI 0.24 to 3.86; participants = 173) could not be established reliably as the trial was small. Evidence was insufficient for assessment of whether use of transurethral radiofrequency collagen denaturation was associated with an increased rate of urinary retention, haematuria and hesitancy compared with sham treatment in 173 participants. The GRADE quality of evidence for all other adverse events with available evidence was low as the result of high risk of bias and imprecision.We found no evidence to inform comparisons of transurethral radiofrequency collagen denaturation with conservative physical treatment, mechanical devices, drug treatment, injectable treatment for UI or other surgery for UI.

AUTHORS' CONCLUSIONS

It is not known whether transurethral radiofrequency collagen denaturation, as compared with sham treatment, improves patient-reported symptoms of UI. Evidence is insufficient to show whether the procedure improves disease-specific quality of life. Evidence is also insufficient to show whether the procedure causes serious adverse events or other adverse events in comparison with sham treatment, and no evidence was found for comparison with any other method of treatment for UI.

Transurethral radiofrequency collagen denaturation for treatment of female stress urinary incontinence: a review of the literature and clinical recommendations

Stress urinary incontinence is a prevalent condition in women with a significant negative effect on quality of life. Intervention includes behavioral modification, intravaginal devices, pelvic floor muscle exercises, biofeedback, functional electrical stimulation, and surgical procedures. We will review a new in-office procedure for the treatment of SUI that may serve as a viable nonsurgical option.

Nonsurgical transurethral radiofrequency treatment of stress urinary incontinence in women

A transurethral radiofrequency collagen denaturation system was recently approved by the US FDA for nonsurgical, outpatient treatment of women with stress urinary incontinence associated with urethral hypermobility. Controlled radiofrequency energy applied through a transurethral probe heats submucosal tissue to produce collagen denaturation, resulting in reduced tissue compliance without necrosis, thus distinguishing this procedure from transvaginal radiofrequency tissue ablation. Treatment can be administered in 30 min under local anesthesia, without incisions, use of cystoscopy or other visualization of the treatment site. Safety and efficacy have been demonstrated in several studies, including a 12-month, multicenter, sham-procedure-controlled clinical trial in 173 women with mild-to-moderate stress urinary incontinence. In patients receiving active treatment, two of the four groups experienced significant quality-of-life changes (p = 0.004; p = 0.02), and all women exhibited significant increases in Valsalva leak point pressure (p = 0.02 vs sham group).