By Temple University School of Podiatric Medicine Journal Review Club

Editor’s note: This post is part of the Temple University School of Podiatric Medicine (TUSPM) journal review club blog series. In each blog post, a TUSPM student will review a journal article relevant to wound management and related topics and provide their evaluation of the clinical research therein.

Article: Extended Extracorporeal Shockwave Therapy for Chronic Diabetic Foot Ulcers: A Case Series

Authors: Chou WY, Wang CJ, Cheng JH, Chen JH, Chen CC, Kuo YR

Journal: Wounds 2019;31(5):132–136

Reviewed by: Alexandra J. Brown, class of 2022, Temple University School of Podiatric Medicine

Introduction

Chronic diabetic foot ulcers (DFUs) affect approximately 13% of the U.S. population.¹ DFUs are defined by the authors of this article as, “nonhealing ulcers of the foot lasting more than 3 months’ duration in patients with diabetes.”² It is critical to treat DFUs effectively and in a timely fashion because ulcers may progress to the point of requiring an amputation. Patients with a DFU may have an amputation rate of 21.5% to 28.4%.³ Non-surgical techniques have been utilized to treat DFUs, including traditional wound care and dressings, infection control, and blood glucose control.²

Given the prevalence of diabetic foot disease and the challenging nature of healing DFUs, researchers are investigating alternate treatment methods. Such treatments include the use of growth factor therapies, tissue-engineered products, and hyperbaric oxygen.⁴ In animal studies, the use of extracorporeal shockwave therapy (ESWT) showed improved tissue generation and blood flow perfusion because ESWT stimulates neovascularization and increases growth factors.² This case series explored the effects of extended ESWT for treatment of DFUs.

Complex Wound Management: Diabetic Foot Ulcers

Material and Methods

The case series followed four patients. One patient received 12 treatments of ESWT, and the remaining three patients received six treatments. The dosage and number of pulses were based on the ulcer size. In addition to ESWT, patients received routine wound care and practiced glucose control.² Local blood flow perfusion scans were completed before and after ESWT with Doppler flowmetry to evaluate tissue viability. In addition, the ulcers were assessed clinically, noting local blood flow perfusion and ulcer severity. Tissue was biopsied for immunohistochemical analysis and histopathological examination.²

Results

Four patients were evaluated for changes in blood flow perfusion rate, ulcer size, and an extensive immunohistochemical analysis. The analysis measured changes in angiogenesis, neovascularization, proliferation, and tissue repair biomarkers, in addition to anti-inflammatory cytokines. Fibronectin levels decreased in all four patients after ESWT.² With the exception of fibronectin, the other biomarkers showed inconsistent outcomes after ESWT. For example, platelet-derived growth factor increased in patients 1, 2, and 4, but it decreased in patient 3.

Discussion

The clinical outcomes were not clearly outlined in the results section of the article. The changes in ulcer size at 24 and 48 weeks after ESWT were mentioned briefly, and it would have been beneficial to report the pre-ESWT ulcer measurements. There were inconsistent results with regard to the effect of ESWT on the levels of biomarkers and anti-inflammatory cytokines. It is impossible to attribute the healing solely to ESWT because this treatment was provided simultaneously with multidisciplinary wound care. A control group would be required to determine whether any effects could be attributed to the ESWT with wound care, as compared with wound care in isolation. The only notable complications were mild local redness and swelling at the application site of ESWT, without any observed systemic or neurovascular complications.

Limitations

The authors acknowledge the small sample size of the case series, with only four patients total. One test group (12 treatments) included only one patient. No statistical significance can be drawn, nor can any notable patterns be determined from such a limited group of patients. Finally, it is also important to recognize the potential for bias related to the second author’s affiliation with the company producing the ESWT device because he is a member of the company’s advisory committee.²

Conclusion

In theory, extended ESWT may be beneficial because of the correlation with increased tissue generation and blood flow perfusion in animals.² However, the current case series does not provide adequate data to support the conclusion that ESWT is an effective treatment for the diabetic foot. Considering the lack of significant complications, future studies with larger sample sizes with a control group may be considered to determine the efficacy of ESWT.

References

1. Zhang P, Lu J, Jing Y, Tang S, Zhu, D; Bi Y. Global epidemiology of diabetic foot ulceration: a systematic review and meta-analysis. Ann Med. 2017;49(2):106-116. doi:10.1080/07853890.2016.1231932

2. Chou WY, Wang CJ, Cheng JH, Chen JH, Chen CC, Kuo YR. Extended extracorporeal shockwave therapy for chronic diabetic foot ulcers: a case series. Wounds. 2019;31(5):132-136.

3. Li X, Xiao T, Wang Y, et al. Incidence, risk factors for amputation among patients with diabetic foot ulcer in a Chinese tertiary hospital. Diabetes Res Clin Pract. 2011;93(1):26-30. doi:10.1016/j.diabres.2011.03.014

4. Schaper NC, Apelqvist J, Bakker K. The international consensus and practical guidelines on the management and prevention of the diabetic foot. Curr Diab Rep. 2003;3(6):475-479. doi:10.1007/s11892-003-0010-4

About the Author

Alexandra J. Brown is a second-year podiatric medical student at Temple University School of Podiatric Medicine (TUSPM) in Philadelphia, Pennsylvania. She graduated from the University of Notre Dame with a Bachelor of Science in Science-Business. Alexandra spent two years as a health care analyst specializing in clinical operations of major hospitals. Affirmed in her goal of becoming a health care provider and serving patients directly, Alexandra completed the Special Master’s Program in Physiology at Georgetown University in 2017. She has published articles in the following journals: Journal of Foot and Ankle Surgery, Foot and Ankle International, Arthroscopy: The Journal of Arthroscopic and Related Surgery, and Knee Surgery, Sports Traumatology, Arthroscopy. In the fall of 2018, she matriculated to TUSPM with a merit scholarship. She serves as the President of the American College of Foot and Ankle Surgery Club at Temple, in addition to serving as Editor and TUSPM Delegate for both the PrePodLife and Hallux Magazine websites. Dr. James McGuire is the director of the Leonard S. Abrams Center for Advanced Wound Healing and an associate professor of the Department of Podiatric Medicine and Orthopedics at the Temple University School of Podiatric Medicine in Philadelphia.