Effectiveness of virtual reality technology combined with conventional pelvic floor rehabilitation training in postpartum myofascial pelvic pain syndrome: A randomized controlled trial.

Myofascial pelvic pain syndrome (MPPS) is characterized by the presence of highly sensitive trigger points within the pelvic floor muscles (PFM) and surrounding musculature. This condition manifests as pelvic floor pain accompanied by myofascial tension or spasm [ 1 , 2 ]. It is one of the common pelvic floor dysfunction disorders affecting women after delivery [ 3 ]. The experience of pain has been shown to cause prolonged fatigue and psychological disorders [ 4 ], which significantly affect the daily lives and occupational functioning of patients with MPPS. Pregnancy is typically associated with significant changes in the musculoskeletal system [ 5 ]. As pregnancy progresses, the gradual increase in fetal weight leads to a corresponding rise in the load on the pelvic floor muscles (PFM) [ 6 ]. Prolonged overloading, as well as acute or repeated microtrauma can cause chronic tightening and contracture of muscle tissue [ 7 ]. This process results in local muscle hypoxia and acidosis, which gradually contribute to the formation of myofascial pain trigger points. The presence of these trigger points induce hypertonia of the PFM, leading to muscle spasms and difficulty in achieving muscle relaxation [ 8 ]. Current rehabilitation modalities include myofascial manipulation release, biofeedback therapy, electrical stimulation, and magnetic therapy, among others [ 9 , 10 ]. All of these treatments require a basic awareness of PFM. However, unlike other skeletal muscles, the contraction and relaxation of the PFM are not easily observable to the naked eye [ 11 ]. Previous research has shown that 70% of women with pelvic floor dysfunction are unable to correctly contract their PFM, and 97% can only achieve a weak contraction [ 12 ]. Effective contraction of the PFM is crucial for restoring its function. Therefore, it is essential to develop methods that enhance sensory perception during PFM training. In recent years, virtual reality (VR) has been extensively utilized in managing musculoskeletal pain, emerging as an effective approach for chronic pain management [ 13 – 17 ]. By immersing individuals in engaging virtual environments, VR provides a multifaceted sensory experience that includes visual, auditory, and tactile stimuli [ 18 ]. Previous studies have demonstrated that VR technology can enhance muscle perception, facilitate muscle relaxation, and improve motor function [ 19 – 22 ]. For individuals with MPPS, impaired sensory perception and reduced relaxation capacity are critical factors that significantly influence both pain recurrence and the effectiveness of PFM training [ 7 , 23 ]. In clinical practice, patients with MPPS are typically instructed to perceive and relax their PFM through verbal guidance or imagery techniques. However, these methods often lack contextual and sensory intuitiveness, resulting in largely unsatisfactory outcomes. To date, no research has investigated the rehabilitative impact of VR technology combined with conventional PFM rehabilitation training for postpartum women with MPPS. This study aimed to investigate the therapeutic potential of VR technology in enhancing PFM proprioception among individuals with MPPS. We hypothesized that VR technology would demonstrate superior efficacy in facilitating both the relaxation and contraction functions of the PFM compared to conventional rehabilitation training alone.

A total of 60 participants were initially selected for inclusion in this study. Three were excluded from the trial group, resulting in a final sample size of 27 participants in that group. Table 2 provides a summary of the basic demographic information for both groups. No statistically significant differences were observed between the groups in terms of age, height, weight, or body mass index (BMI)( P  > 0.05). Following the intervention, a significant difference was observed between the two groups regarding relaxation time during the rapid contraction phase ( P  < 0.05), as shown in Table 3 . The experimental group demonstrated a shorter recovery period from maximum contraction to the resting state. Table 4 shows the differences in musculoskeletal ultrasound measurements of PFM between the two groups. There were no statistically significant differences in the thickness or Young’s modulus of the PFM at both the resting state and maximum contraction state following the intervention ( P  > 0.05). Fig 4 shows the comparison of VAS scores between the two groups. There was no statistically significant difference in VAS scores after the intervention ( P  > 0.05). However, both the experimental and control groups demonstrated a significant reduction in VAS scores following the intervention compared to pre-treatment levels ( P  < 0.05), as illustrated in Fig 5 . One year after the conclusion of the project intervention, an online questionnaire survey was conducted among the participants. A total of 26 women from the experimental group participated, while one woman did not. Similarly, 29 women from the control group participated, with one woman also not participating. The statistical analysis of the five follow-up questions showed no significant difference between the two groups ( P  > 0.05), as illustrated in Figs 6 – 10 . Finally, the perceptions and experiences of the participants in the experimental group following VR therapy are presented in Fig 11 .

Virtual reality can enhance the relaxation capacity of fast-twitch muscle fibers in the pelvic floor muscles, thereby improving their motor function. However, it does not increase muscle thickness or reduce muscle pain. This study has several limitations that should be acknowledged. First, the design included only two VR scenes, resulting in a limited number of training scenarios for participants and making it difficult to accommodate diverse participant preferences. Second, all participants were diagnosed with mild MPPS, which limited the ability to demonstrate significant efficacy. Third, the sample size was relatively small. Additionally, MPPS is a complex multisystem disorder, and the efficacy achieved through VR alone may be insufficient. Therefore, a multidisciplinary and multi-technological approach is essential.

This randomized controlled clinical trial recruited participants from March 1, 2023, to December 29, 2023. A total of 60 eligible subjects were enrolled and randomly assigned to either the experimental group or the control group. The study was conducted at the Third People’s Hospital and the Rehabilitation Hospital affiliated with Fujian University of Chinese Medicine. Ethical approval was granted by the Ethics Committee of the Rehabilitation Hospital affiliated with Fujian University of Chinese Medicine (approval number 2022KY-025–01. Ethical approval was obtained in written form. This study was registered on March 20, 2023, at https://www.chictr.org.cn/index.html (registration number ChiCTR2300069517). Participants who expressed willingness to participate and signed the written informed consent form were then assessed for eligibility. The study participants consisted of women who experienced MPPS, characterized by moderate to severe pelvic pain lasting at least six months, along with identifiable trigger points detected through palpation assessment. Inclusion criteria were as follows: (1) postpartum women meeting the MPPS diagnostic criteria [ 24 ]; (2) aged between 20 and 45 years; (3) hypertonicity of the PFM as determined by the Glazer assessment. Exclusion criteria included: (1) reproductive system-related diseases (e.g., endometriosis, acute pelvic inflammatory disease, pelvic venous congestion syndrome); (2) urinary system-related diseases (e.g., interstitial cystitis, recurrent urinary tract infection, urethral diverticulum); (3) digestive system-related diseases (e.g., irritable bowel syndrome, inflammatory bowel disease, diverticular colitis); (4) neurological disorders (e.g., brain injury, spinal cord injury, severe cognitive impairment); (5) postmenopausal women; (6) contraindications for pelvic floor ultrasonography; (7) unclean lochia; and (8) a history of pelvic girdle pain. In this study, the Visual Analog Scale (VAS) was chosen as the primary measure of symptom improvement in patients with MPPS. Based on this outcome, a two-sided test with α = 0.05, a confidence level power (1-β) of = 0.8, and an expected effect size of 0.83 were established. Using G*Power 3.1 software, the required sample size for each group was calculated to be 24 participants per group. Additionally, accounting for a potential attrition rate of 20%, the total sample size required need for this study was ultimately determined to be 60 participants. The project supervisor used SPSS version 25.0 to sequentially compile 60 datasets labeled 1 through 60. Random numbers were generated using the software’ s random number generator with a fixed seed value of 2,000,000. After ranking these numbers, participants were sorted in ascending order based on their ranks: those with ranked 1 to 30 were assigned to the experimental group, while those ranked 31 to 60 were allocated to the control group. Sixty eligible MPPS participants were enrolled and assigned sequential numbers (1–60) based on their enrollment dates. The randomization sequence, generated using SPSS 25.0, was securely stored by an independent researcher who was not involved in treatment or assessment. Using this pre-generated sequence, participants were randomized into either the VR training group or the control group. Group assignments were disclosed to eligible participants by the project coordinator during their initial treatment session. The control group received general pelvic floor physical therapy using the Vishee Pelvic Floor Rehabilitation Instrument (model SA9800). The therapy comprised the following components: (1) Electrical stimulation therapy, with a the frequency was set at 50 Hz, a duration of 2 seconds, and a pulse width ranging from 200 to 320 μs. The current intensity was gradually increased from 0 to the patient’s comfort threshold not exceeding 60 mA, and was applied for 10 minutes per session. (2) pelvic floor muscle training, where the training intensity was determined based on the results of the participants’ PFM evaluation results. The training intensity was set between 50% and 80% of the maximum PFM contraction strength. All participants followed to the voice-guided instructions from the biofeedback device, performing a 5-second PFM contraction followed by a 5-second relaxation phase. This cycle was repeated for 10 minutes per session. (3) Abdominal breathing exercises, conducted for 10 minutes following the voice prompts. Each treatment session lasted 30 minutes. A total of 10 treatments treatment sessions were administered, with an average frequency of 2–3 times per week. The experimental group received the same electrical stimulation and PFM training as the control group, with the addition of relaxation training facilitated by VR glasses (Pico 4k). In the designed simulated scenarios-Scenario 1 (Ocean, Fig 1 ) and Scenario 2 (Swing, Fig 2 ), — participants selected a scene based on their comfort level. Participants engaged in deep inhalation and slow exhalation synchronized with the rhythm of the visual display and auditory cues. During inhalation, subjects followed the guidance of a virtual character to slightly distend their abdomen while simultaneously relaxing the PFM, extending and relaxing toward the end of the body in accordance with the wave or swing movement. During exhalation, participants were instructed to slowly exhale through the mouth while contracting the abdomen and moving the PFM back and upward in harmony with the wave or swing. All treatments were administered by the same physiotherapist Fig 3 . The Glazer assessment (Vishee, SA9800) was used to evaluate the surface electromyography (s-EMG) of the PFM in both groups before and after the intervention. The evaluation process is divided into five stages [ 25 ]: (1) Pre-resting stage: average s-EMG value (reference range: 2–4μV) and variability (reference range: < 0.2); (2) Rapid contraction stage: average s-EMG value (reference range: 35–45μV), and relaxation time (<0.5seconds). (3) Tension contraction stage: the average s-EMG value (reference range: 30–40μV), relaxation time (<1second), and variability (reference range: < 0.2); (4) Endurance contraction stage: average s-EMG value (reference range: 25–35μV), and variability (reference range: < 0.2); (5) Post-resting stage: values consistent with those observed during the preceding resting phase. The musculoskeletal ultrasound device (ACUSON Sequoia Silver) was used to measure the thickness and Young’s modulus of PFM. Muscle thickness is positively correlated with and muscle contraction function. Shear wave elastography (SWE) was employed to obtain the Young’s modulus of the PFM. The Young’s modulus value reflects muscle stiffness and tension, with higher values indicating increased tissue stiffness and muscle tension [ 26 , 27 ]. Following the standardized measurement position and protocol for PFM ultrasound examination [ 28 ], we assessed the thickness and Young’s modulus of the PFM at rest and during maximum contraction. The Visual Analogue Scale (VAS) [ 29 ] was used to assess the level of pain experienced during the palpation of the PFM, both before and after treatment. An online questionnaire survey was administered to the participants one year after the intervention concluded. The questionnaire primarily included the following items (see Table 1 ): The analysis was conducted using SPSS (Version 27). Data normality was assessed through visual inspection and the Shapiro-Wilk test. Continuous variables were reported as mean (SD) or median (first quartile[Q1]−third quartile[Q3]). The Student’s t-test or Mann–Whitney U test was employed to compare baseline characteristics and outcomes—including VAS, s-EMG, thickness, and Young’s modulus of the PFM—between the two groups before and after the intervention. Within-group comparisons were performed using the paired t-test. A p-value of less than 0.05 was considered statistically significant throughout the analysis. Follow-up visits with participants were conducted from December 29, 2024, to January 10, 2025.

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