Abstract
Background:
Dyspareunia, a prevalent sexual dysfunction in young women, is often overlooked and affects sexual health and quality of life. Physical therapy can reduce pain and improve muscle function.
Aim:
To investigate the effects of capacitive resistive monopolar radiofrequency combined with perineal massage on dyspareunia-related pain and muscle strength.
Methods:
A single-blinded, randomized clinical trial with 44 women aged 18–30 years experiencing sexual pain. The intervention group received manual therapy with perineal massage and 448 kHz capacitive resistive monopolar radiofrequency, while the control group received the same treatment with the device off. They underwent four 16-minute sessions. Evaluations were performed at baseline, posttreatment, and 3 months later.
Outcomes:
Pain during various activities, muscle strength, perceived pain during intercourse, and sexual satisfaction.
Results:
The intervention group showed significant improvements in manual stretching (p = 0.046), pain during instrumental insertion (p = 0.031), instrumental stretching (p < 0.001), Oxford scale scores (p = 0.006), pain scores (p < 0.001), and sexual satisfaction (p = 0.004), sustained at 3 months. The control group improved in instrumental stretching (p = 0.002), pain scores (p < 0.001), and sexual satisfaction (p = 0.002). Instrumental stretching had a large effect size (Cohen’s d = 2.049).
Clinical Implications:
Physiotherapy provides effective pain relief in young women with dyspareunia.
Strengths and Limitations:
Short treatment with good results but not always with pain-free results, and there is a need to combine treatment with other health professionals.
Conclusion:
The combination of capacitive resistive monopolar radiofrequency and manual therapy improves pain feeling and muscle function and sustains its effects long term.
Introduction
Dyspareunia refers to persistent or recurrent genital pain before, during, or after sexual activity.1,2 It can vary in intensity and location, affecting sexual pleasure and leading to avoidance of sexual contact.1,3 This condition is classified as a genitopelvic pain/penetration disorder and has a negative impact on sexual health and quality of life, with a higher prevalence among women. 3
The prevalence of dyspareunia in young women in Europe varies according to the measurement method used. Studies have reported prevalence rates ranging from 13% to 79%. For example, a study conducted in Sweden found that 77% of women experienced pain during penetration for more than 6 months, 4 while another study in the same country showed a dyspareunia prevalence of 79% among women aged 13–21 years. 5 In Belgium, dyspareunia is reported as sexual difficulty (19.7%) and sexual dysfunction (14.6%). 6 In the United Kingdom, the prevalence among women aged 16–34 years is 34.5%. 7
Dyspareunia is often pharmacologically managed by physicians using tricyclic antidepressants, opioid analgesics anticonvulsant, and topical anesthetics.8,9 Physiotherapy, specifically manual therapy techniques such as perineal massage or trigger point treatment, is considered a workable option for treating dyspareunia despite limited scientific evidence.1,3 Perineal or Thiele massage, primarily used for pregnant women, shows promise in improving dyspareunia caused by tension in the pelvic floor muscles, particularly the levator ani. 10 Although several participants initially find perineal massage uncomfortable and painful,11,12 they often experience decreased pain and softening of the perineum after a few sessions.1,12
Physiotherapists use electrophysical agents based on radiofrequency to relieve inflammation and enhance tissue elasticity. 13 Capacitive-resistive monopolar radiofrequency (CRMRF) at 448 kHz has been used to increase endogenous temperature, 14 leading to improved blood circulation,15,16 reduced inflammation,13,15,17 and pain.13,15,17–21
This treatment also improves muscle tissue, 13 normalizes muscle tone,13,17 enhances muscle strength and function, 18 and reduces muscle spasms.13,18,20
In this study, two hypotheses were established to evaluate the effectiveness of the combination of CRMRF with perineal massage as manual therapy in patients with dyspareunia. The null hypothesis (H0) proposes that a combination of these techniques does not produce any significant improvement in pain associated with dyspareunia, muscle strength, or the patient’s perception of treatment. In contrast, the alternative hypothesis (H1) posits that the combined use of CRMRF and perineal massage significantly improves pain related to dyspareunia and muscle strength, in addition to having a positive impact on the patient’s perception of the treatment. This allows for an objective analysis of the effectiveness of therapy using rigorous statistical comparisons.
Materials and Methods
Experimental, analytical, longitudinal, and prospective single-blinded, randomized controlled clinical trial in women presenting with symptoms associated with dyspareunia.
This study was conducted at a university facility from November 2021 to February 2023. This study was evaluated and approved by the Ethics Committee for Animal and Human Experimentation of the Universitat Autònoma de Barcelona (CEEAH-UAB) with project number 5671 and was included in Clinical Trials (registration number #NCT5844189).
All participants signed two informed consents, one to participate in the study following the Declaration of Helsinki and the other one for intracavitary assessment and treatment.
Population and sample
Participants were recruited from the general population and contacted after responding to the initial survey. The study population consisted of young women (aged 18–30 years) who experienced pain during sexual intercourse. Selection: The inclusion criteria were women aged 18–30 years with pain during sexual intercourse. The exclusion criteria included absolute contraindications to the treatment (pregnancy, breastfeeding, cardiac pathologies, epilepsy, acute inflammatory processes, pacemakers, and skin infections in the treatment area) and any condition that would impair the understanding of informed consent.
Sample size
The sample size was calculated using the GRANMO Sample Size Calculator, considering the prevalence reported in the literature and explained in the introduction of this article, for two study groups. A 95% confidence level (α = 0.05) and 80% statistical power (β = 0.2) were used, with a two-tailed test. A standard deviation of 4.9 was assumed (based on the literature review), and a correlation of 0.9 was estimated between the initial and subsequent measurements. It was calculated that 21 participants were needed in each group to detect a difference of ≥2 units. A 10% loss to follow-up was estimated, resulting in an initial sample size of 44 participants. Three participants were lost during the intervention and one during the follow-up period. The final sample size included 40 participants.
Study groups and randomization
Participants were divided into two study groups, and randomization was ruled out using a random.org automatically generated sequence. Participants were aware of their assigned codes but were blinded to the treatment received. In all treatment sessions, the device was placed such that participants could not see their status or manipulation. After the assignment, only the principal investigator and her collaborators knew the group to which the participants belonged. All participants were informed that the sensation of increasing temperature was variable and may not always occur.
Intervention
The control group received manual therapy treatment without CRMRF (the treatment was performed with the device turned off as a sham intervention). The intervention group received manual therapy treatment with CRMRF at a frequency of 448 kHz, 200 W of resistive output, and 450 VA of capacitive output (Intradermik device, Rös’s Estética®, Castelldefels, Spain).
Outcomes
The sample description variables were age (years) and responses to the study variables collected during the initial assessment. The study variables included pain on digital palpation and intracavitary stretching, pain on vaginal dilator insertion, pain on instrumental stretching (mmHg), muscle strength (Modified Oxford Scale), pain during sexual intercourse (visual analog scale [VAS]), and perceived sexual satisfaction during intercourse (VAS). During the assessment, a vaginal intracavitary examination was performed to evaluate pain in different situations. Pain on digital palpation was assessed by palpating the levator ani muscle with one or two fingers (depending on the participant’s condition and pain threshold). Responses were recorded as Yes/No. Pain on manual stretching was evaluated by performing stretching with one or two fingers on the levator ani muscle; the response was recorded as yes/no. Pain on vaginal dilator insertion was assessed with the progressive introduction (from smallest to largest) of 4 Feminaform® dilators (22 × 85 mm, 27 × 105 mm, 32 × 135 mm, and 37 × 160 mm in diameter × length); the response of pain occurrence was recorded as Yes/No, along with the corresponding measurement. Pain on instrumental stretching was evaluated using an Epi-NO® device inserted into the vagina, and the pressure was slowly and progressively increased to inflate the balloon until pain occurred, and the value of the achieved pressure was recorded. Muscle strength was assessed using the modified Oxford Scale (0–5) on both vaginal walls (left and right). Pain during sexual intercourse was assessed using a VAS ranging from 0 to 10. The intervention protocol was standardized to limit variability in the interventions.
Treatment protocol
The intervention lasted for 20 weeks per participant and consisted of seven sessions (four treatment sessions, one per week, and three data collection sessions: initial, after the four treatment sessions, and 3 months after the intervention). The session’s protocol was standardized to limit the variability of the interventions. Treatment sessions were started by asking the patient about any adverse reactions or discomfort experienced since the last session. Treatment was administered according to the participants’ assigned study group. Ultrasound gel (Clear Ultrasound Gel, OXD Professional Care®, REF US-C1) and two different types of electrodes were used: a capacitive electrode (30 mm diameter flat electrode for personal use) and a resistive electrode (cylindrical, stainless steel, 8 cm long and 1.5 cm in diameter, with a screw-on plastic cap to prevent heat concentration). To measure the temperature applied during the treatment, a Thermal Sensitivity Scale (TSS) (0–9) was used for temperature feeling, where 0 represents no temperature and 9 represents the maximum tolerable temperature before burning.
Procedure for the intervention group
With the patient in a supine position on the treatment table with a cylindrical cushion under the knees, a rectangular return plate (passive electrode) was placed under the lumbar area. Gel was applied (as needed) on the electrodes and on the fingers (covered with gloves) of the physiotherapist. Step 1: 3 min of indirect application of the capacitive electrode at 3% power on the patient’s urogenital triangle using continuous longitudinal and transverse movements within the area between the lower edge of the pubic symphysis, ischial area, and ischiopubic ramus. A translabial application was also performed. TSS of 0–2. Step 2: 5 min of direct intracavitary application of the resistive electrode at 25% power. Up and down movements of the vaginal walls. TSS of 5–6. Step 3: 5 minutes of capacitive electrode application, alternating between indirect and semidirect methods, with power between 8% and 12%, following the same procedure as in step 1. In addition, intracavitary manual therapy (Thiele massage) was applied to the vaginal walls, massaging from the origin to the insertion of the levator ani muscle with pressure tolerable to the patient, performing back and forth movements on the entire palpable muscle surface, and a maneuver from the vagina’s depth to the exterior (7). TSS of 5–6. Step 4: Same as step 1. TSS of 0–2. The control group used the same procedure but with the device turned off.
Data collection and analysis
Data collection was conducted using a digital survey; responses were exported to an Excel spreadsheet for later coding. Participants responded using their assigned code, and it was impossible to identify them during the process (only the principal investigator had access to the code patient’s identity list). All included patients were analyzed, except for those who withdrew from the study before completion (n = 4). Statistical analyses were conducted using IBM SPSS Statistics software (v20), including normality tests (Shapiro–Wilk test), descriptive variables (percentages; contingency tables, descriptive statistics as mean, standard deviation, 95% confidence interval, minimum and maximum values), and comparison of means in related samples within groups (t-test for mean differences in parametric distributions and nonparametric Wilcoxon test for non-normal distributions). The outcomes analyzed were final—initial, 3 months—final, and 3 months—initial. Additionally, a comparison of means between groups was performed using the nonparametric Mann–Whitney U test. Significant changes were considered when the results yielded a p value ≤0.05.
Results
The intervention began with 42 female participants, which increased to 44 participants following the withdrawal of 2 individuals, with a mean age of 22.6 years (standard deviation, SD = 2.7). At the first visit, all participants experienced pain during manual stretching, 84.1% experienced pain during digital palpation, and all experienced pain during dilator insertion. The mean value for the onset of pain during instrumental stretching was 17.6 mmHg (SD = 8.1); the mean Oxford scale score was 3.2 (SD = 1.5) on the right vaginal wall and 2.8 (SD = 1.5) on the left one. The mean pain score during sexual intercourse was 7.4 points (SD = 1.6), and the mean self-reported satisfaction score during intercourse was 7 (SD = 2.1). There were no significant differences between the study groups before the intervention. The values separated by group are listed in Table 1.
Participant Status Before Intervention
VAS, visual analog scale.
In the control group, significant improvements were observed in instrumental stretching (p = 0.002), pain score (p < 0.001), and subjective perception of sexual satisfaction (p = 0.002). When comparing the results of the assessment at 3 months with those of the initial assessment, significant improvements were observed in pain during instrumental insertion (p = 0.031), instrumental stretching (p = 0.026), pain score (p < 0.001), and subjective perception of sexual satisfaction (p = 0.013).
In the intervention group, comparing pre- and postintervention assessments, significant improvements were observed in manual stretching (p = 0.031), pain during instrumental insertion (p = 0.031), instrumental stretching (p < 0.001), Oxford scale score (p = 0.006/p = 0.001), pain score (p < 0.001), and subjective perception of sexual satisfaction (p = 0.004). When comparing the results of the assessment at 3 months with the initial assessment, significant improvements were observed in digital palpation pain (p = 0.004), manual stretching (p = 0.008), pain during instrumental insertion (p = 0.031), instrumental stretching (p < 0.001), Oxford scale score (p = 0.002, p = 0.001), pain score (p < 0.001), and subjective perception of sexual satisfaction (p = 0.001). An extended version of the results is presented in Table 2 and Table 3.
Comparison after Four Treatment Sessions
Significant p-values (p ≤ 0.05) are indicated with an *. All comparisons were made using their baseline values.
Comparison 3 Months After Treatment
Significant p-values (p ≤ 0.05) are indicated with an *. All comparisons were made using their baseline values.
When comparing the results between the two groups, significant changes were observed in the intervention group compared with the control group on digital palpation (p = 0.048), manual stretching (p = 0.046), instrumental stretching (p = 0.006), and Oxford scale score (p = 0.006) in the pre- and post-intervention comparison. Comparing the groups with the results of the final and initial assessments, significant changes were observed in instrumental stretching (p = 0.012, Cohen’s d = 0.846 meaning a large effect of the treatment) and Oxford scale scores (p = 0.024, Cohen’s d = 0.001 for right vaginal wall, and p = 0.005, Cohen’s d = 0.990, meaning a large effect only for the left vaginal wall). A complete version of the results is presented in Table 4.
Comparison Between Groups
Significant p-values (p ≤ 0.05) are indicated with an*.
Statistical analyses showed that the differences between the changes in the results of referred pain (p = 0.581) and satisfaction during intercourse (p = 0.977), as measured using the VAS, were not statistically significant between the control and intervention groups. These p-values indicate that no significant differences were observed between the groups on these specific variables, suggesting that the intervention had no differential impact on referred pain or satisfaction during intercourse compared to the control group.
Regarding the main variable of the study, pain during instrumental stretching, the calculation of Cohen’s d resulted in a value of 2.049. This result implies a large or very large effect size, following the criteria established by Cohen, who defined a large effect from a value of 0.8. This suggests that the combination of CRMRF with perineal massage had a clinically relevant and substantial impact on the reduction of pain during instrumental stretching, with a significant difference between the groups, reinforcing the effectiveness of this intervention for the treatment of dyspareunia.
Based on the results obtained, the calculation of statistical power for the main variable of the study (instrumental pain) yielded a value of 1.0, considering an effect size of d = 2.049, a significance level of 0.05, and a sample size of 21 participants per group. This statistical power value indicates a 100% probability of detecting a real effect, which reinforces the robustness of the results and ensures that the study is adequately designed to identify statistically significant differences between groups. The observed large effect size, combined with maximum statistical power, suggests that the intervention had a substantial impact on instrumental pain reduction.
Discussion
Main findings and interpretation
This study treated muscle pain associated with levator ani hypertonia. Our study showed that the combination of manual therapy (Thiele massage) and CRMRF is more effective in reducing pain than manual therapy alone. Although both groups showed significant improvements in pain score and perception, the group that received the combination of therapies experienced additional improvements, such as manual palpation and instrumental stretching.
Both groups experienced significant improvements in the VAS score, instrumental stretching with Epi-No, and introduction of vaginal dilators, showing that manual therapy is effective in treating dyspareunia, as it has been shown in previous studies. 1 It is interesting to emphasize that the control group received only four 5-minute sessions of manual therapy. The intervention group had the added benefit of CRMRF and showed additional improvements in manual palpation and stretching in addition to improvements in VAS, Epi-No, and dilators. On the contrary, improvements were observed in the intervention group from the first posttreatment assessment, while improvements were observed in the control group at the 3-month mark after the intervention (when compared to the baseline). This is related to the ability of CRMRF to shorten healing times, 15 contribute to pain reduction,13–15,17,18,20,21 and maintain its effects over time. 22
When comparing the two treatment groups, we observed that the group receiving manual therapy combined with CRMRF showed significant improvements in manual evaluation (palpation and stretching) and instrumental stretching. Combining manual therapy with radiofrequency improves muscle elasticity13,19,23 and normalizes muscle tone,13,17,19 as shown in our results. In addition, muscle strength improved in the intervention group without specific treatment or instructions to improve this aspect. Decreasing levator ani muscle hypertonia improves muscle function1,18 in terms of contraction and relaxation. The results of both groups were maintained over time, showing no significant differences in the retest at 3 months. This is consistent with previous studies that show that the outcomes of physiotherapy interventions can be maintained for 3–6 months. 1
Physicians often pharmacologically manage dyspareunia.8,9 Research considers treatment effectiveness partly based on the proportion of women who can resume (or initiate) sexual activity at the end of treatment. However, this does not mean that discomfort is no longer present or that sex is necessarily pleasant. It is a dysfunction that requires a multidisciplinary approach. 1 However, there is limited evidence on physiotherapy treatment, which aims to treat the dysfunction from its muscular origin and shows effective results in reducing pain during sexual intercourse and improving the quality of life of women.
Strengths and Limitations
To assess pain more comprehensively and objectively, this study included manual techniques (vaginal palpation), instrumental techniques (dilators and Epi-No), and VAS. Although these instrumental techniques are commonly used as treatments, they were also employed as evaluation tools in this study. The purpose of this study was to evaluate pain during penetration by simulating different components of sexual intercourse, such as penis diameter and length (using dilators) and stretching of the vaginal walls (with Epi-No). The goal was to reduce subjectivity in the assessment through vaginal palpation. Furthermore, the protocol used in this study is concise, easy to implement by any pelvic floor physiotherapist, highly reproducible, and has shown significant improvements.
On the contrary, assessing pain is always challenging because individuals have varying interpretations and thresholds. We have made efforts to evaluate it through multiple approaches to obtain a comprehensive and global understanding. As part of the data collection process, we included brief questions, allowed for open-ended responses. A significant percentage of the participants, upon completion of the study and after experiencing a reduction or even resolution of their pain, expressed that if they had known they could have pain-free sexual intercourse, they would have rated their initial pain with higher scores. It would also have been remarkably interesting to conduct the study using a double-blind approach, with the physiotherapist who performed the assessments blinded to the group to which the participants belonged. However, it was not possible to implement this approach due to the research team’s limited size and lack of necessary human or financial resources.
Conclusions
Dyspareunia is an often encountered issue in young women and has received inadequate attention in research. Physiotherapy, which incorporates perineal massage among other techniques and treatments, has emerged as an effective approach to address this problem by offering pain relief and reducing the necessity for medication in these women. The inclusion of CRMRF in manual therapy not only shortens the treatment duration but also sustains its long-term effects. In addition, it improves muscle function without specifically targeting it.
Conducting studies that contribute to our understanding of therapeutic options for dyspareunia is crucial, given the considerable number of affected women and the limited scientific evidence available in this field. Further research, involving a broader range of young women from various locations, would help reinforce the preliminary findings from this study.
Footnotes
Authors’ Contributions
A.A.P.: Main researcher. Contributed to the conception, design and planning the research project. She also carried out the intervention and contributed writing up the results and this research article. A.A.-P.: Researcher. Contributed to the conception, design and planning the research project. She also carried out the intervention and contributed to the analysis, writing up the results and this research article. L.F.: Researcher. Contributed in the carrying out of the intervention and contributed writing up the results and this research article. J.E.-C.: Thesis director. Contributed to the conception, design and planning the research project. He also contributed to the analysis of the results and the review process of this research article. J.L.-J.: Thesis director. Contributed to the review process of this research article. Antonio G.-M.: Thesis tutor. Contributed to the review process of this research article. M.C.O.: Researcher. Contributed in the design and carrying out of the intervention and to the review process of this research article.
Data Availability Statement
The data supporting the findings of this study are available from the corresponding author upon reasonable request.
Patient Consent Statement
This study involved human participants, and written informed consent was obtained from all individuals included in the study. Participants were provided with detailed information regarding the study’s objectives, procedures, potential risks, and benefits. They were assured that their participation was entirely voluntary and that they had the right to withdraw from the study at any time. Participants were informed that their data would be used in scientific publications and presentations. They understood that their personal information would be kept confidential, and any identifying details would be anonymized in any publication arising from this study.
Author Disclosure Statement
The authors do not have any interests to disclose.
Funding Information
The authors report there was no funding to declare.
