Cayan S. et al., 2026: Effects of Low-Intensity Shock Wave Therapy on Erectile Function and Penile Vascular Parameters in Men with Erectile Dysfunction: A Systematic Review and Meta-Analysis of Randomized Controlled Studies.

Cayan S, Pinggera GM, Alipour H, Shah R, Şahin B, Altay B, Mostafa T, Dimitriadis F, Dardmeh F, Kumar N, Alarcon DCA, Fathalla N, Sheibak N, Rahman SM, Gouri A, Moreno-Sepulveda J, Daoud S, Anagnostopoulou C, Ryzhkov A, Toprak T, Arafa M, Ceyhan E, Rashed A, Palani A, Pescatori E, Al Hashimi M, Khalafalla K, Cannarella R, Falcone M, Chung E, Agarwal A
World J Mens Health. 2026 Feb 13. doi: 10.5534/wjmh.250266

Abstract

Purpose: This systematic review and meta-analysis of randomized controlled trials evaluated the effects of low-intensity shock wave therapy (LiSWT) on erectile function (EF) and penile vascular parameters in men with erectile dysfunction (ED), compared with controls receiving sham or no treatment.

Materials and methods: A systematic search of Scopus, PubMed, and Cochrane databases identified studies assessing LiSWT in men with ED. Primary outcomes were changes in the International Index of Erectile Function (IIEF)-5 and the IIEF-EF domain scores. Secondary outcomes included erection hardness score (EHS), sexual encounter profile (SEP) diary Q2 and Q3, global assessment question (GAQ) scores, and penile Doppler ultrasound parameters-peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistive index (RI). Changes from baseline to the end of follow-up were compared between LiSWT and control groups.

Results: Of 527 retrieved articles, 12 met inclusion criteria. Pooled analysis demonstrated significantly greater improvements in the LiSWT group for IIEF-5 (standardized mean difference [SMD], 1.19; 95% confidence interval [CI], 0.47-1.91; p=0.001) and IIEF-EF (SMD, 1.24; 95% CI, 1.02-1.45; p<0.001) scores compared with controls. No significant differences were found for EHS (p=0.698), SEP-Q2 (p=0.934), SEP-Q3 (p=0.985), GAQ (p=0.993), and penile Doppler ultrasound parameters, including PSV (p=0.855), EDV (p=0.995), or RI (p=0.818).

Conclusions: LiSWT provides modest improvements in IIEF scores but fails to produce significant changes in other functional or vascular parameters. These findings suggest that while LiSWT may offer some benefit, the clinical relevance is limited for most patients. Current evidence does not support its routine inclusion in ED treatment algorithms. Future research should focus on identifying patient subgroups most likely to experience significant and sustained improvements from this therapy.

Comment Jens Rassweiler

This systematic review and meta-analysis evaluated whether focused low-intensity shock wave therapy (LiSWT) improves erectile function and penile vascular parameters in men with erectile dysfunction (ED), using only controlled randomized studies.

Background

Erectile dysfunction is common, especially with increasing age, but it also affects younger men. It is often linked to vascular disease, diabetes, hypertension, cardiovascular disease, lifestyle factors, psychological stress, and endothelial dysfunction. Because erection depends heavily on penile blood flow, vascular health is central to erectile function. Common tools used to assess ED include:

• IIEF / IIEF-EF: International Index of Erectile Function, especially the erectile function domain.
• IIEF-5: A shorter version used to assess ED severity.
• EHS: Erection Hardness Score.
• SEP-Q2 and SEP-Q3: Questions assessing successful vaginal penetration and intercourse.
• GAQ: Global Assessment Question about perceived improvement.
• Penile Doppler ultrasound: Measures penile vascular parameters such as peak systolic velocity, end-diastolic velocity, and resistive index.

Purpose of the Study

The authors aimed to assess the effectiveness of LiSWT in men with ED by including only controlled studies, such as sham-controlled or no-treatment-controlled trials. This was intended to provide stronger evidence than previous reviews, many of which included uncontrolled or observational studies.

Material and Methods

The search identified 527 abstracts. After removing duplicates, irrelevant papers, and studies without usable data, the final analysis included 12 controlled studies. The outcomes analyzed included:

• IIEF-5, IIEF-EF, EHS, SEP-Q2, SEP-Q3, GAQ
• Peak systolic velocity, or PSV, End-diastolic velocity, or EDV Resistive index, or RI

Results

1. IIEF-5 Scores

Six studies reported IIEF-5 outcomes.

LiSWT significantly improved IIEF-5 scores compared with control treatment.

• Pooled standardized mean difference: 1.19; 95% confidence interval: 0.47 to 1.91 (p-value: 0.001)

This suggests that LiSWT had a statistically significant positive effect on patient-reported erectile function. However, there was substantial heterogeneity, meaning the results varied considerably between studies.

2. IIEF-EF Scores

Six studies reported IIEF-EF outcomes.

LiSWT also significantly improved IIEF-EF scores compared with control.

• Pooled standardized mean difference: 1.24; 95% confidence interval: 1.02 to 1.45 (p-value: <0.001)

This was one of the strongest findings of the analysis and supports a measurable improvement in erectile function based on validated questionnaires.

3. Erection Hardness Score

Six studies assessed EHS.

LiSWT did not significantly improve erection hardness compared with control.

• Pooled standardized mean difference: 0.28; 95% confidence interval: -1.14 to 1.70 (p-value: 0.698)

The evidence for EHS was highly inconsistent across studies.

4. SEP-Q2, SEP-Q3, and GAQ

Only two studies provided usable data for these outcomes, so the evidence was very limited. The results did not show a reliable or conclusive treatment effect. The confidence intervals were extremely wide, meaning the estimates were imprecise.

5. Penile Doppler Ultrasound Parameters

Only two studies reported Doppler ultrasound outcomes. LiSWT did not significantly improve PSV, EDV, and RI

These findings suggest that while LiSWT may improve questionnaire-based erectile function scores, it has not been clearly shown to improve objective penile vascular measurements.

Clinical Interpretation

The review found that LiSWT produces modest but statistically significant improvements in IIEF-based erectile function scores. However, it did not significantly improve erection hardness, intercourse success measures, patient global assessment, or penile Doppler vascular parameters.This creates an important distinction:

• Patients may report better erectile function on validated questionnaires.
• But objective vascular improvements remain uncertain.
• Functional outcomes such as erection hardness and successful intercourse were not consistently improved.

Guideline Context

The article notes that current guidelines remain cautious.

• The American Urological Association considers LiSWT investigational.
• The Canadian Urological Association conditionally recommends against routine use.
• The European Association of Urology allows LiSWT as an alternative option in selected men with vasculogenic ED, especially after proper counseling.
• The Italian Society of Andrology and Sexual Medicine gives a weak recommendation because benefits appear modest and long-term effects remain uncertain.

Limitations

The review highlights several limitations including mall sample sizes in many studies, high heterogeneity in treatment protocols, differences in shock wave energy, pulse number, treatment duration, and sham procedures. Studies have limited long-term follow-up, and very few studies reported Doppler ultrasound outcomes (n=2).

Conclusion

LiSWT may offer modest improvement in erectile function scores, especially IIEF-5 and IIEF-EF, in men with ED. However, it does not currently show consistent improvement in erection hardness, sexual encounter success, global patient-reported improvement, or objective penile vascular parameters.

The authors conclude that current evidence does not support routine inclusion of LiSWT in standard ED treatment algorithms. It may be considered in selected, well-informed patients, but larger, standardized, long-term randomized controlled trials are needed to determine who benefits most, what protocol works best, and whether the improvements are clinically meaningful and durable.

Jens Rassweiler