Effects of extracorporeal shockwave therapy on pain and pelvic floor function in women with pelvic floor myofascial pain: a retrospective cohort analysis.

This study was approved by the Research Ethics Committee of Hualien Tzu Chi Hospital (institutional review board permit number: IRB113-164-B). The Research Ethics Committee of our hospital waived the requirement for informed consent due to the low risk to patient safety. The Declaration of Helsinki conducted this study. Relevant guidelines and regulations were implemented for all the methods. This study was designed as a retrospective cohort study. We reviewed the medical records of women diagnosed with PFMP who received ESWT between July 2022 and February 2024. Baseline assessments (pre-treatment) and follow-up evaluations after four weeks of ESWT were compared to assess changes over time. A consecutive sampling strategy was used. All women diagnosed with PFMP who received ESWT at our pelvic floor clinic between July 2022 and February 2024 and met the eligibility criteria were included. This approach ensured that every eligible patient during the study period was captured, thereby reducing the risk of selective enrollment or provider-driven patient selection. Eligible participants were women diagnosed with PFMP based on a comprehensive pelvic floor examination demonstrating reproducible myofascial tenderness or trigger points. Additional inclusion criteria were: (1) age ≥ 18 years, (2) completion of baseline symptom assessments, and (3) receipt of the full four-session ESWT protocol. Exclusion criteria included: (1) pregnancy, (2) active pelvic or urinary tract infection, (3) history of pelvic surgery within the preceding six months, (4) known neurological or musculoskeletal disorders affecting pelvic floor function, and (5) incomplete clinical data or failure to complete the ESWT treatment course. A detailed history, including menopause status, parity, delivery mode, surgical history, and gynecologic history, was taken. Pelvic ultrasonography was performed to evaluate gynecologic disorders associated with PFMP. A pelvic examination was performed by intravaginal palpation of the bilateral pelvic muscle region (both sides of levator ani and obturator internus) [ 18 ]. Pelvic muscle tenderness with a trigger point or fibromuscular fibrosis band may be palpated. In this retrospective study, PFMP was diagnosed using a standardized clinical examination protocol. A diagnosis of PFMP required: (1) reproducible myofascial tenderness elicited on palpation of the pelvic floor muscles; (2) presence of palpable myofascial trigger points or taut muscular bands; (3) reproduction of the patient’s characteristic pelvic pain during examination; and (4) absence of alternative structural causes such as pelvic organ prolapse, active infection, or masses. All examinations were performed by an experienced examiner (DCD) with clear diagnostic criteria and consistent clinical assessment. All patients with PFMP received ESWT using the DUOLITH SD1 T-TOP machine (STORZ MEDICAL, Tägerwilen, Switzerland). The treatment was performed perpendicular on the upper and lower vulvar region with every 500 pulses on the right side and then on the upper and lower vulvar region with every 500 pulses on the left side (probe: F-SW, 2000 hits, energy: 0.3–0.35 mJ/mm 2 with frequency 4 Hz) (Fig.  1 ). Each patient received four consecutive treatments per week. Fig. 1 The location of extracorporeal shock wave therapy (ESWT). Bilateral upper and lower vulva regions received ESWT The location of extracorporeal shock wave therapy (ESWT). Bilateral upper and lower vulva regions received ESWT The severity of pain was measured using the Visual Analogue Scale (VAS), where a score of 10 represents the most severe pain and a score of 0 represents no pain. Pain score was measured at baseline and 4 weeks after treatment. Pelvic floor dysfunction was measured using the Pelvic Floor Disability Inventory-20 (PFDI-20). PFDI-20 is a 20-question self-reported survey that measures the influence and severity of PFD symptoms in three domains: pelvic organ prolapse distress symptoms (POPDI-6: PFDI-20 question 1–6, score 0–24 (higher = worse symptoms)), colorectal-anal distress symptoms (CRADI-8: colorectal-anal distress inventory-PFDI question 7–14, score 0–32 (higher = worse symptoms)), and urinary distress symptoms (UDI-6: urinary distress inventory-PFDI question 15–20, score 0–18 (higher = worse symptoms)). To enhance transparency, all variables, definitions, and measurement methods used in this study are summarized in Supplementary Table 1. The results were evaluated at baseline and 4 weeks after treatment. No other therapy for PFMP was applied. The four-week follow-up interval reflects the standard short-term assessment timeframe used in our clinic for monitoring ESWT responses. This study, therefore, evaluated short-term within-patient symptom changes rather than the long-term durability of treatment effects. All pelvic floor examinations and PFMP diagnoses were performed or supervised by clinicians experienced in pelvic floor disorders. VAS and PFDI-20 assessments were completed by patients and documented by trained clinical staff. Because this patient group was a retrospective clinical cohort, neither the outcome assessors nor the patients were blinded to treatment, which introduced potential reporting bias. All 20 patients completed both pre- and post-treatment assessments. There were no missing VAS or PFDI-20 data; therefore, no imputation procedures were required. Previous studies have reported commonly used clinically meaningful thresholds (e.g., ≥ 2-point change on VAS; ~13–15 point change on PFDI-20 subscales in other pelvic floor conditions) [ 19 , 20 ]. Given the exploratory design and PFMP-specific literature gaps, these thresholds should be interpreted cautiously. We now explicitly state that the study evaluates statistical rather than clinically validated meaningful change. Treatment-emergent adverse events (AEs) were collected through self-report. The investigator evaluated the relationship between AEs and ESWT. Because this was a retrospective exploratory study including all eligible patients, no prospective sample size or power calculation could be performed. Continuous variables are presented as medians and interquartile ranges (IQRs). To evaluate changes over time in this single-cohort study, no regression modeling was performed. Therefore, assessment of multicollinearity was not applicable. Issues of overfitting were also not applicable. Non-parametric methods were used when descriptive analysis indicated non-normality. Therefore, pre–post comparisons performed using the Wilcoxon signed-rank test were appropriate. There were no missing data for VAS, PFDI-20, or demographic variables; all patients completed both pre- and post-treatment assessments. Therefore, no imputation procedures were necessary. Due to the small sample size, model fit indices were not calculated. All analyses were performed using SPSS 24.0 (IBM Corp., Armonk, NY, USA). In all cases, p values less than 0.05 were considered statistically significant.

A total of 20 women with PFMP who received ESWT were included (Table  1 ). The median age was 55.0 years (IQR: 47.5–63.0). Thirteen women (65%) were menopausal. The median parity was 2 (IQR: 1.5–2.5), and one patient (5%) was nulliparous. Most participants delivered vaginally (normal spontaneous delivery, 75%), while 15% had a cesarean section and 5% had both delivery modes. Ultrasound findings revealed benign gynecologic conditions in some patients, including uterine myomas (20%), adenomyosis (15%), and ovarian cysts (5%). Table 1 Demographics ( n  = 20) Characteristics Value [ n (%) or median (Q1, Q3)] Age (years) 55 (47.5, 63) Menopause  No 7 (35%)  Yes 13 (65%) Parity 2 (1.5, 2.5)  1 4 (20%)  2 10 (50%)  >3 5 (25%) Nulliparity 1 (5%) Delivery mode  NSD 15 (75%)  C/S 3 (15%)  NSD + C/S 1 (5%) Ultrasound finding  Myoma 4 (20%)  Adenomyosis 3 (15%)  Ovarian cyst 1 (5%) NSD Normal spontaneous delivery, C/S Cesarean section Demographics ( n  = 20) NSD Normal spontaneous delivery, C/S Cesarean section Table  2 summarizes the VAS, PFDI-20, and subscale scores before and after ESWT. The median VAS score decreased significantly from 7.0 at baseline to 2.0 after 4 weeks ( p  < 0.01). The median PFDI-20 score decreased significantly from 33.0 to 26.5 ( p  < 0.01). Subscale scores changed as follows: POPDI-6 significantly decreased from 11.0 to 8.0 ( p  < 0.01); CRADI-8 decreased significantly from 13.0 to 10.0 ( p  < 0.05); and UDI-6 decreased significantly from 10.0 to 9.0 ( p  < 0.01). Table 2 The scores of VAS and PFDI-20 of the patients with PFMP before and after extracorporeal shock wave therapy ( n  = 20) Measure Before Median (IQR) After Median (IQR) Median Diff (IQR) P -value VAS 7.0 (2.5) 2.0 (1.5) –5.0 (3.0) < 0.01 PFDI-20 33.0 (13.0) 26.5 (9.0) –5.0 (9.5) < 0.01 POPDI-6 11.0 (4.5) 8.0 (4.0) –2.0 (5.0) < 0.01 CRADI-8 13.0 (5.5) 10.0 (4.0) –1.0 (4.0) < 0.05 UDI-6 10.0 (5.0) 9.0 (3.0) –1.0 (3.0) < 0.01 IQR Interquartile range, IQR, VAS Visual Analogue Scale, PFDI-20 Pelvic floor dysfunction inventory-20m, POPDI-6 Pelvic Organ Prolapse Distress Inventory-6, CRADI-8 Colorectal-anal distress inventory-8, UDI-6 Urinary distress inventory-6, IQR Interquartile range, Diff Difference The scores of VAS and PFDI-20 of the patients with PFMP before and after extracorporeal shock wave therapy ( n  = 20) IQR Interquartile range, IQR, VAS Visual Analogue Scale, PFDI-20 Pelvic floor dysfunction inventory-20m, POPDI-6 Pelvic Organ Prolapse Distress Inventory-6, CRADI-8 Colorectal-anal distress inventory-8, UDI-6 Urinary distress inventory-6, IQR Interquartile range, Diff Difference Table  3 summarizes the Wilcoxon effect sizes (r) and corresponding 95% bootstrap confidence intervals for the pre–post changes in pain and pelvic floor symptom measures. Pain intensity (VAS) showed an effect ( r = − 0.8796, 95% CI: − 0.8878 to − 0.8791). Effect sizes were observed for prolapse-related symptoms (POPDI-6; r = − 0.7158), urinary distress (UDI-6; r = − 0.7014), and overall pelvic floor dysfunction (PFDI-20; r = − 0.7319). The colorectal-anal subscale (CRADI-8) demonstrated an effect ( r = − 0.5387) with a wider confidence interval. Table 3 Effect Sizes and 95% Bootstrap Confidence Intervals for Pre–Post Changes in Pain and Pelvic Floor Symptom Scores after ESWT ( n  = 20) Outcome Effect size ( r ) 95% CI (Bootstrap) VAS –0.8796 –0.8878 to − 0.8791 POPDI-6 –0.7158 –0.8176 to − 0.5992 CRADI-8 –0.5387 –0.7890 to − 0.1709 UDI-6 –0.7014 –0.8285 to − 0.4845 PFDI-20 –0.7319 –0.8582 to − 0.5297 VAS Visual Analogue Scale, PFDI-20 Pelvic floor dysfunction inventory-20, POPDI-6 Pelvic Organ Prolapse Distress Inventory-6, CRADI-8 Colorectal-anal distress inventory-8, UDI-6 Urinary distress inventory-6, CI Confidence interval Effect Sizes and 95% Bootstrap Confidence Intervals for Pre–Post Changes in Pain and Pelvic Floor Symptom Scores after ESWT ( n  = 20) VAS Visual Analogue Scale, PFDI-20 Pelvic floor dysfunction inventory-20, POPDI-6 Pelvic Organ Prolapse Distress Inventory-6, CRADI-8 Colorectal-anal distress inventory-8, UDI-6 Urinary distress inventory-6, CI Confidence interval

Chronic pelvic pain (CPP) affects an estimated 6%–27% of women worldwide and is characterized by cyclic or non-cyclic pelvic pain lasting at least six months, leading to significant functional limitation and health burdens [ 1 , 2 ]. Its causes are diverse and often overlapping, spanning gynecologic, urinary, gastrointestinal, musculoskeletal, and neurologic systems [ 3 ]. Pelvic floor myofascial pain (PFMP) is increasingly recognized as a key contributor to CPP, arising from hypertonicity and trigger points within the pelvic floor musculature that produce reproducible tenderness and regionally referred pain [ 4 – 6 ]. PFMP is frequently associated with urinary, bowel, and sexual symptoms and contributes to impaired physical functioning and quality of life. Despite reported prevalence estimates ranging from 14% to 78% in the general population and 14%–23% among women with CPP [ 7 ], PFMP remains underdiagnosed due to variable presentation and the need for thorough clinical examination [ 8 ]. Conventional management for PFMP includes pelvic floor physical therapy, pharmacologic treatments, behavioral interventions, and adjunct modalities such as electrical stimulation or acupuncture [ 9 ], yet many patients continue to experience persistent symptoms. Evidence from related fields suggests potential benefit from targeted physical therapy modalities; a systematic review showed that manual therapy and electrotherapy effectively reduced pain in women with primary dysmenorrhea [ 10 ], and another meta-analysis reported improved erectile function among men receiving extracorporeal shockwave therapy (ESWT) for erectile dysfunction [ 11 ]. These findings highlight growing interest in non-invasive modalities like ESWT as potential options for managing chronic pain and functional impairment. ESWT has been applied in male urologic conditions such as chronic prostatitis/CPP syndrome [ 12 ]. PFMP shares core pathophysiological features with other myofascial pain syndromes, such as trigger point formation, hypertonicity, and localized nociceptive sensitization [ 5 , 13 ]. ESWT has demonstrated analgesic and myofascial-modulating effects [ 14 ]. Prior studies have shown that ESWT may influence tissue perfusion, reduce neuromuscular hypersensitivity, and disrupt myofascial trigger points, suggesting a potential relevance to PFMP [ 15 , 16 ]. However, the specific mechanistic pathways in female pelvic floor musculature remain insufficiently understood and require dedicated investigation [ 5 ]. PFMP’s impact on mobility and daily functioning, combined with the limited availability of useful non-invasive therapies, makes ESWT a promising therapeutic option [ 17 ]. Given the high prevalence of PFMP, diagnostic heterogeneity, and the lack of standardized criteria, these factors may influence case identification and reported rates [ 18 ]. In the present study, PFMP was identified using a standardized pelvic floor examination protocol (reproducible myofascial tenderness and trigger-point palpation). We hypothesized that ESWT would be associated with: (1) a reduction in pain intensity measured by the Visual Analogue Scale (VAS), and (2) an improvement in pelvic floor–related functional impairment measured by the Pelvic Floor Disability Inventory-20 (PFDI-20) and its subscales. To address this evidence gap, we aim to explore whether the application of ESWT is associated with reductions in pain intensity and pelvic floor dysfunction scores among patients with PFMP.

In this retrospective cohort, reductions in pain intensity were observed over the four-week ESWT treatment period. All twenty patients demonstrated decreases in VAS scores, reflecting within-patient changes in reported pain levels. Pelvic floor symptoms assessed using the PFDI-20 also showed lower scores at follow-up, indicating a reduction in symptom burden within the study population. Across subscales, decreases were observed in all PFDI-20 domains, including the POPDI-6, which reflects prolapse-related symptoms. Effect sizes ( r  = − 0.54 to − 0.88) with corresponding 95% bootstrap confidence intervals indicated magnitudes of pre–post change. These findings reflect within-group associations and should be interpreted cautiously, given the small, observational sample. The prior research has explored ESWT in male CPP syndromes [ 21 ]. These studies are not directly comparable to the current context due to fundamental differences in pelvic anatomy, neuromuscular structures, and underlying etiologies between men and women. The application of ESWT in female PFMP should therefore be considered independently of male CPP findings. References to male studies are included solely to illustrate the broader clinical use of ESWT and do not imply mechanistic equivalence or comparable treatment responses [ 22 ]. Further research is needed to elucidate the specific physiological effects of ESWT on female pelvic floor musculature. To our knowledge, only one previous study has reported the application of ESWT in female PMFP and showed inconsistent results in 3 patients [ 17 ]. They used only one instance of 3000 focused shock waves at 3 Hz and an energy level of 0.25 mJ/mm² (half on the most painful point, half on the gluteal region). In our study, ESWT was administered in four sessions, each consisting of 2,000 focused shock waves delivered at 4 Hz with an energy level of 0.3–0.35 mJ/mm² across four vulvar points. Variability in treatment parameters across studies may be associated with the differences in reported outcomes. Based on prior ESWT studies in male myofascial pain and chronic pelvic pain [ 23 ], similar associations were anticipated in women with PFMP. In this cohort, ESWT was associated with reductions in pain intensity and pelvic floor symptom scores, which reflect short-term within-patient changes. These findings are preliminary and should be interpreted with caution due to the small cohort size and retrospective design. In our study, no patients had objective prolapse, and reported symptoms such as pelvic heaviness or pressure are common in PFMP [ 24 ]. The POPDI-6 subscale showed a decrease after treatment. Because ESWT was applied perineally using a focused probe, it is possible that the treatment targeted muscles located near the vaginal area [ 25 ]. The observed reduction in prolapse-related symptoms may reflect changes in discomfort localized to these regions, but definitive conclusions cannot be drawn from the current study. A previous study reported that ESWT could improve stress urinary incontinence (SUI) in female patients [ 26 ]. A single-blind, randomized controlled trial also demonstrated that ESWT could improve SUI [ 27 ]. A previous study showed that ESWT can improve symptoms in patients with interstitial cystitis/bladder pain syndrome [ 28 ]. ESWT may improve SUI by enhancing urethral and vaginal smooth muscle, increasing urethral wall thickness, promoting neuromuscular integrity, restoring urothelial integrity, and increasing progenitor cell populations [ 29 ]. Taken together, ESWT may also be associated with improvement in SUI. Similarly, our study showed a decreased SUI symptom score. PFMP is characterized by focal myofascial trigger points and increased pelvic floor muscle tone [ 5 , 30 ]. The mechanisms underlying the clinical benefits of ESWT in improving PFMP and pelvic floor function in women remain unclear. It has been postulated that ESWT may alleviate pain by reducing pain mediators and modulating the nociceptive pathway [ 14 , 31 ]. In the context of improving pelvic floor function, neovascularization, musculature regeneration, and collagen remodeling have been considered [ 29 ]. Within-patient changes were compared with published minimal clinically important difference (MCID) thresholds from related populations [ 32 ]. Prior studies have suggested that a reduction of approximately 1.5–2.0 points on the VAS represents a clinically meaningful change in chronic pain conditions [ 33 ]. MCID estimates for the PFDI-20 range from approximately 13 to 15 points in women with pelvic floor disorders [ 19 ]. In the present cohort, the median reductions in VAS exceeded commonly cited pain MCID thresholds. But changes in PFDI-20 scores approached did not uniformly reach MCID values. Importantly, these MCID benchmarks were derived from populations with pelvic organ prolapse or urinary incontinence rather than PFMP [ 19 ]. Their applicability to this condition remains uncertain. Accordingly, reductions in VAS scores may reflect clinically meaningful change, whereas changes in PFDI-20 may represent statistical significance without clear clinical relevance. This study offers several strengths. All participants underwent a consistent ESWT protocol, and outcomes were measured using validated scales, allowing for reliable within-patient comparisons. Consecutive recruitment minimized selection bias, and the complete dataset enabled unambiguous pre- and post-assessment of symptom changes. Also, we have delineated the MCID thresholds of the treatment based on the data from this study and have discussed their uncertain applicability to PFMP. In interpreting these findings, it is important to consider the methodological limitations of this study. Our findings are hypothesis-generating rather than practice-changing. The small sample size and retrospective, single-center design restrict the generalizability of the results. Also, the reliance on subjective, self-reported measures introduces the possibility of measurement and reporting bias. Because there was no control group, the observed pre–post changes cannot be distinguished from natural symptom fluctuation or placebo effects, and no causal conclusions can be drawn. The follow-up period was limited to 4 weeks, preventing an assessment of the durability of the symptom changes. The sustained benefit of ESWT remains unknown. Neither patients nor outcome assessors were blinded, further increasing the potential for expectation and reporting bias. Accordingly, effect sizes in small, unblinded samples should be interpreted descriptively rather than as indicators of efficacy. Additionally, multiple statistical comparisons were performed without correction, potentially increasing the risk of Type I error. Therefore, some statistically significant findings may represent chance associations rather than true effects and should be interpreted cautiously. The effect size should be interpreted with extreme caution in small samples, unblinded settings, and subjective outcome measures. The observed effect sizes do not equate to strong evidence of efficacy. Some PFDI-20 subscales demonstrated only modest changes, indicating that symptom responses may vary across domains. We also acknowledge that the diagnostic variability described in the literature underscores the challenges of defining PFMP and may limit the generalisability of our findings. Future studies should prioritize prospective, controlled trials to demonstrate the treatment effects of ESWT in women with PFMP. Additionally, longer-term follow-up is necessary to assess the durability of symptom changes and to establish optimal treatment intervals.

The application of ESWT is associated with decreased pain intensity and reduced pelvic floor dysfunction scores in patients with PFMP. However, short-term, within-patient change remains the dominant interpretative frame. As such, ESWT is described as associated with symptom reductions rather than implying effectiveness. These preliminary, within-patient findings support a call for larger, controlled prospective trials.

Supplementary Material 1. Supplementary Material 1.