Optical coherence tomography evaluation of vaginal epithelial thickness during CO2 laser treatment: A pilot study

Lasers in Gynecology

The first published reports on the use of laser for cervical pathology date back to 1973. Technical advancements in flexible and rigid laser fibers revolutionized video laser laparoscopy in the 1990s. Fractionated lasers have been used to treat vulvovaginal symptoms associated with genitourinary syndrome of menopause, lichen sclerosus, and urinary incontinence. Review of available data suggests that fractionated lasers can improve both subjective and objective signs of vaginal atrophy and lichen sclerosus, but the evidence is weak because most of the trials are underpowered, are at risk for bias, and lack long-term follow-up. There is no strong evidence to support fractionated laser therapy for urinary incontinence or low-level laser therapy for chronic pelvic pain. Although short-term, single-arm trials suggest benefit of fractionated laser therapy for genitourinary syndrome of menopause, lichen sclerosus, and urinary incontinence, additional adequately powered, prospective, randomized, and longer-term comparative trials are needed before lasers can be recommended for these specific conditions. The purpose of this Clinical Expert Series is to review basic laser biophysics and the mechanism of action for modern fractionated lasers as relevant to the gynecologist. We also summarize safety and effectiveness data for lasers used for some of the most commonly studied gynecologic conditions: the vulvovaginal atrophy component of genitourinary syndrome of menopause, lichen sclerosus, and urinary incontinence.

OCT angiography in the monitoring of vaginal health

Fractional-pixel CO2 laser therapy shows promise for treating the genitourinary syndrome of menopause (GSM). Nevertheless, it remains controversial in the field of female pelvic medicine. This is due to the inherent difficulties in obtaining noninvasive biopsies to evaluate the treatment's efficacy and safety objectively. To address this challenge, we developed a noninvasive intravaginal optical coherence tomography (OCT)/OCT angiography (OCTA) endoscopic system, whose probe features a shape identical to the laser treatment probe. This system can provide high-resolution OCT images to identify the microstructure of vaginal tissue and visualize the vasculature network in vivo. We conducted clinical research on 25 post-menopausal patients with GSM. OCT/OCTA scans were acquired at four different locations of the vagina (distal anterior, distal posterior, proximal anterior, and proximal posterior) during the whole laser treatment session. A U-Net deep learning model was applied to segment the vaginal epithelium for assessing vaginal epithelial thickness (VET). Blood vessel density and VET were quantified to monitor the efficacy of fractional-pixel CO2 laser therapy. Statistical correlation analyses between these metrics and other clinical scores were conducted, validating the utility of our system. This OCT/OCTA endoscopic system has great potential to serve as a noninvasive biopsy tool in gynecological studies to screen, evaluate, and guide laser treatment for GSM.

Depth-Resolved Attenuation Mapping of the Vaginal Wall under Prolapse and after Laser Treatment Using Cross-Polarization Optical Coherence Tomography: A Pilot Study

Vaginal wall prolapse is the most common type of pelvic organ prolapse and is mainly associated with collagen bundle changes in the lamina propria. Neodymium (Nd:YAG) laser treatment was used as an innovative, minimally invasive and non-ablative procedure for the treatment of early-stage vaginal wall prolapse. The purpose of this pilot study was to assess connective tissue changes in the vaginal wall under prolapse without treatment and after Nd:YAG laser treatment using cross-polarization optical coherence tomography (CP OCT) with depth-resolved attenuation mapping. A total of 26 freshly excised samples of vaginal wall from 26 patients with age norm (n = 8), stage I-II prolapses without treatment (n = 8) and stage I-II prolapse 1-2 months after Nd:YAG laser treatment (n = 10) were assessed. As a result, for the first time, depth-resolved attenuation maps of the vaginal wall in the B-scan projection in the co- and cross-polarization channels were constructed. Two parameters within the lamina propria were target calculated: the median value and the percentages of high (≥4 mm-1) and low (<4 mm-1) attenuation coefficient values. A significant (p < 0.0001) decrease in the parameters in the case of vaginal wall prolapse compared to the age norm was identified. After laser treatment, a significant (p < 0.0001) increase in the parameters compared to the normal level was also observed. Notably, in the cross-channel, both parameters showed a greater difference between the groups than in the co-channel. Therefore, using the cross-channel achieved more reliable differentiation between the groups. To conclude, attenuation coefficient maps allow visualization and quantification of changes in the condition of the connective tissue of the vaginal wall. In the future, CP OCT could be used for in vivo detection of early-stage vaginal wall prolapse and for monitoring the effectiveness of treatment.

Light and energy-based therapeutics for genitourinary applications: Consensus on protocols and best practices

BACKGROUND

Lasers and energy-based technologies have been developed for genitourinary applications over the past several decades.

AIMS

This consensus article aims to categorize the published articles and clinical trial data that culminated in protocol development of technology for genitourinary applications, and to develop consistent parameters in future clinical trials.

MATERIALS AND METHODS

The published articles and clinical trials data on lasers and energy-based devices applied to genitourinary conditions were categorized according to device and condition and consensus developed on protocols and parameters.

RESULTS

The devices in genitourinary applications were classified as fractional lasers, radiofrequency and high-intensity focused electromagnetic field therapy. The consensus of the protocols and parameters based upon the published clinical trials of their application to the vaginal and urologic conditions associated with genitourinary syndrome of menopause was developed and organized according to device and condition.

DISCUSSION

The status of FDA clearances and future pathways are discussed.

CONCLUSIONS

This consensus article categorizes and presents the protocols and practices for the main classes of lasers and energy-based devices for genitourinary applications in future clinical trials.