The Science of Shockwave Therapy
An evidence-based exploration of extracorporeal shockwave therapy (ESWT), from its biophysical principles to its role in modern clinical practice for chronic musculoskeletal disorders.
A Brief History of Shockwave in Medicine
From crushing kidney stones to regenerating tendons, the clinical use of shockwave has evolved significantly over the past 50 years.
Fundamental Principles
[cite_start]A shockwave is a pressure disturbance that moves rapidly through a medium[cite: 6]. Unlike other waves, it is defined by a very fast pressure rise and a biphasic waveform, which are key to its therapeutic effects.
Modality Variants: Focused vs. Radial
True, Convergent Shockwave
[cite_start]Generated by piezoelectric, electromagnetic, or spark discharge sources[cite: 40]. [cite_start]The energy converges to a precise focal point, making it essential for 'surgical' interventions[cite: 42].
Key Applications:
Key Waveform Characteristics
Mechanisms of Action
[cite_start]The strongest argument for shockwave's efficacy is that it takes a tissue from a chronic to a more acute state, providing a trigger to a 'stalled' repair sequence[cite: 100]. This is achieved through several established effects.
Pro-Inflammatory Response
[cite_start]Stimulates an inflammatory response, which is relevant for recalcitrant tissues[cite: 99]. [cite_start]This involves the release of Substance P and prostaglandin E2[cite: 105].
Increased Blood Flow & Activity
[cite_start]Increases local blood flow and stimulates cellular activity, including the release of growth factors like VEGF and TGFβ, which are critical for repair[cite: 98, 105].
Transient Analgesia
[cite_start]Provides a temporary, transient analgesic effect on afferent nerves, helping to break chronic pain cycles[cite: 106].
Breakdown of Calcifications
[cite_start]The mechanical energy, particularly from cavitation bubble collapse during the low-pressure phase, helps break down calcific deposits, primarily in tendons[cite: 91, 107].
Evidence-Based Dosing Guide
[cite_start]Effective therapy depends on the applied energy, number of shocks, and number of sessions[cite: 130]. Select a condition to see typical parameters from clinical trials.
Type
Energy
Pulses
Sessions
The Evidence Snapshot
[cite_start]The weight of evidence is more supportive of the intervention than not[cite: 158]. [cite_start]Based on current research, it would be difficult to justify excluding shockwave as a therapy for chronic tendinopathy[cite: 159].
The Library: Safety & Resources
Safe application requires a thorough understanding of contraindications. [cite_start]It is normal to err on the side of caution with emerging therapies[cite: 168].