Extracorporeal shock wave therapy for plantar fasciitis

Physics

A shock wave is a transient pressure disturbance or acoustic energy wave that propagates rapidly in three-dimensional space [5]. Shock waves have unique characteristics including high-pressure amplitudes (>100 MPa) with rapid rise times (approximately 5 nanoseconds), a short life cycle, and a tensile wave with a frequency spectrum ranging from the audible to the ultrasonic region (16 Hz–20 MHz). Shock waves can alter the mechanical, electrical, and thermal properties of the media through which

Physiologic effects

The physiologic effects consist of two different mechanisms. The very rapid positive pressure generates direct mechanical effects (primary effect). The tensile phase or the drop in pressure to even negative pressure generates mechanical forces by cavitation (secondary effect). Tensile forces of the shock wave are greater than the tensile strength of water in interstitial fluid, generating cavitation bubbles and energy growth. The bubbles collapse (implode), and energy is released in the form of

Methods of shock wave generation

In the use of shock wave therapy, there exist three primary methods of shock wave generation. As shown in Fig. 1, these include the piezoelectric, electrohydraulic, and electromagnetic methods. The basic concept of each device is the same: a shock wave is generated, focused, and transferred to the body with appropriate contact medium.

The piezoelectric principle consists of a large number (usually >1000) of piezocrystals (mounted on the inside of a sphere) that receive a rapid electric

FDA-approved devices

The High Medical Technologies was approved in October 2000 by the FDA for ESWT of proximal plantar fasciitis. The Ossatron device uses electrohydraulic principles to produce a wave. The machine sends an electric impulse to an electrode that is centered in a bowl-shaped brass ellipsoid and immersed in a salt-water solution. The water at the gap junction is vaporized, creating a high-intensity pressure wave that is bounced off of the ellipsoid and focused at a focal point outside the device. This

Plantar fasciitis

Plantar fasciitis is the most common cause of heel pain. As shown in Fig. 2, pain typically presents at the medial calcaneal tubercle but may also present along the entire course of the plantar fascia. This tubercle is the point on the calcaneus at which the plantar fascia attaches and is one of the origins of the abductor hallucis, flexor digitorum brevis, and abductor digiti minimi muscles [6]. The bony prominence often develops into a spur (also shown in Fig. 2) due to reactive osseous

Extracorporeal shock wave therapy

Until recently, treatment for plantar fasciitis consisted of only conservative and surgical intervention. ESWT now offers a nonsurgical option for the treatment of plantar fasciitis.

Dornier Epos Ultra case studies/analysis

As part of the FDA approval process of the Dornier Epos Ultra, a clinical investigation sponsored a double-blind, placebo-controlled trial that randomized 302 patients with chronic plantar fasciitis to receive either active or placebo treatment. The patient selection criteria were designed to select patients who would otherwise be considered candidates for surgery and included a minimal 6-month duration of symptoms, pain greater than 5 on a 10-point visual analog scale, and failure of at least

Other case studies/research

Ogden et al [18] evaluated 302 patients with chronic plantar fasciitis treated with ESWT. Overall, 3 months after one treatment, 56% of the treated patients had a successful result compared with the patients treated with a placebo. The study showed that the application of electrohydraulic-generated shock waves is a safe and effective nonsurgical method for treating chronic, recalcitrant heel pain syndrome [18].

Chen et al [19] studied the effectiveness of shock waves on painful heel spur

Other applications

Treatment of nonunion and delayed unions with shock wave therapy has become a popular topic of research. High-energy shock wave therapy seems to be an effective noninvasive tool for stimulation of bone healing in properly selected patients [22]. One study revealed that shock wave therapy has a similar success rate to surgical treatment for chronic nonunion (but has no surgical risks). The study concluded that shock wave therapy is safe and effective in the treatment of chronic nonunion of long

Summary

Shock wave therapy is quickly becoming a mainstay treatment for chronic recalcitrant plantar fasciitis, and many more applications for this therapy may exist. Many advances have been made in regard to this modality of treatment in just a few decades since it was first investigated in the 1950s. Much research has been conducted, revealing the physics and physiologic effect of shock wave therapy. Devices are now approved that produce shock waves for medicinal purposes by one of the three primary