Hypothesis / aims of study
Provoked vestibulodynia (PVD) is the most common subtype of vulvodynia. It is characterized by a sharp pain at the vestibule of the vagina in response to the application of pressure (attempted vaginal penetration, tampon insertion, sexual activity or speculum examination). Women with PVD suffer from psychological distress and dysfunctions affecting all aspects of their sexuality, as well as significant marital difficulties. Despite the availability of some treatments for women with PVD, patients are confronted with limited treatment options with insufficient or conflicting evidence supporting first-line treatments [1]. Non-invasive and non-ablative therapeutic approaches are therefore needed. High Intensity Laser Therapy (HILT) was shown effective for treating various chronic pain conditions [2]. However, there is a lack of evidence supporting the feasibility, acceptability and effects of HILT for PVD, which needs to be addressed. We are, therefore, the first to propose a prospective study exploring the use of HILT in women with PVD.
The primary objective was to assess the feasibility and acceptability of HILT in women with PVD. The secondary objectives were to explore the effects of active and sham HILT on pain intensity, satisfaction and perceived improvement.
Study design, materials and methods
A parallel, 2-group, randomized prospective feasibility study was conducted. The design and methodology comply with the recommendations of the CONSORT extension for pilot and feasibility trials [3]. The participants were women aged 18-45 years old who had been suffering from PVD for at least three months. More specifically, women needed to report pain at the entry of the vagina during vaginal intercourse with a pain intensity greater than 5 on a numerical rating scale (NRS). The eligibility of the participants was confirmed by a standardized pelvic examination performed by a gynecologist from our team. Women were randomized into the active (n=20) or sham HILT (n=20) groups. Both groups received bi-weekly sessions for 6 weeks (total of 12 sessions). Fifteen minutes prior to the irradiation, an anesthetic ointment (benzocaine 2.5% + lidocaine 5% + procaine 2.5%) was applied to the vulvar area and a stream of cold air was blown onto the area during the treatment to mask the warming effects. Women in the active HILT group were treated with the Laser Fotona; Nd : Yag 1064 nm while women in the sham HILT received the same treatment regimen using a deactivated probe.
Patients, outcome assessors and data analysts were blinded to group assignation. An experienced pelvic floor physiotherapist who was not involved in the laser intervention, conducted the baseline and 2-week post-treatment assessments. The attendance rate at laser sessions (≥80% of participants attending ≥10 sessions), the dropout rate (˂15%) and the absence of serious adverse events served as feasibility and acceptability outcomes and benchmarks. To explore the effects, patients’ perceived improvement (patient’s global impression of change), satisfaction (numerical rating scale 0-10), and mean pain intensity during intercourse (numerical rating scale 0-10) were also assessed. A sample of 40 participants was determined to provide sufficient power for evaluating the feasibility and acceptability outcomes (adherence p 75%; 𝛿 15 %; dropout 20%). Chi-square tests were used to compare the two groups for the proportion of participants. Paired and independent t-tests were conducted to examine the effects of treatment.
Results
Out of the 266 participants that showed interest in the study, 45 participants were eligible to participate. Of these, 40 participants were enrolled in the study since their PVD diagnosis was confirmed with the standardized gynecological exam. All the women included (n=40) underwent a baseline assessment and randomization (sham n=20 and active HILT n=20). All participants completed the 12 sessions, except for two women who had 11 sessions due to Covid-related reasons. The dropout rate was only 2.5% (one participant withdrew from the active HILT due to time constraints). No serious adverse events were reported by the patients nor the therapists in either group. Nonetheless, a temporary minor irritating or itching sensation was reported in both groups (sham n=2 and active n=6; p=0.12).
As for treatment effects, a significant reduction in pain from baseline to post-treatment was observed in both groups. Indeed, a significant reduction in pain from baseline to post-treatment was found in women in the active HILT group (baseline 7.3±1.3; post-treatment 4.1±2.2, p<0.001) and in women in the sham group but to a lesser magnitude (baseline 7.4±1.6; post-treatment 5.4±3.2; p=0.002). Women in the active HILT group were more satisfied with the treatment (mean of 6.6/10 (SD 2.8)) than women in the sham group (4.6/10 (SD 3.1)) (p<0.05). Regarding the patients’ global impression of change, more women in the active HILT group reported significant improvement (79%) than in the sham group (47%) (p=0.03). Interestingly, 10% of women in the sham group reported a worsening of their condition.
Interpretation of results
Pre-established benchmarks for the attendance and dropout rates were surpassed, supporting the feasibility and acceptability of this intervention for women with PVD. In contrast to other lasers, such as CO2 and Er:YAG with larger wavelengths, our study, using an Nd:Yag laser, considered a “cold” laser, revealed no serious adverse events. Only temporary mild irritation and minor itching (lasting less than one hour) were reported in both groups. Participants associated their minor symptoms with the use of the topical anesthetic and the intensity of the cooling system. These parameters require special attention for future trials. Women in the active HILT group showed a significant reduction in pain intensity from baseline to post-treatment, greater satisfaction, and a greater perceived change compared to the control group. It is important to highlight that the control group (sham HILT) also had a significant reduction in pain intensity from baseline to post-treatment. This provides further evidence on the relevance of a control group in chronic pain trials due to the placebo effect that may occur. The findings of this study therefore inform the design and methodology to perform a full-scale, adequately powered, randomized controlled trial to confirm the efficacy of HILT treatment for women suffering from PVD.
Concluding message
In conclusion, this study supports the feasibility and acceptability of HILT as an intervention to treat women with PVD. With significant improvements observed in terms of pain, satisfaction, and perceived improvement, this study provides a new level of evidence on HILT, which is a promising non-invasive and non-ablative treatment for women with PVD. The findings of this study identified recommendations for conducting a large randomized controlled trial to confirm the efficacy of HILT.