Focused shock wave therapy for pain-free daily activity.

 The group of musculoskeletal discorders we frequently use for both radial and focused shockwave therapy are: plantarfasciosis, achilles tendinosis, patella tendinosis (runners knee), greater trochanteric pain syndrome, rotator cuff pain syndrome and both medial and lateral epicondylosis (golfers and tennis elbow).  The conditions we are better off treating with focused shockwave are: greater trochanteric pain syndrome, any of the aforementioned conditions involving enthesopathy (insertional tendinosis), calcific tendinopathies, non-union of fracture and in cases where radial shockwave is too painful to use.

These conditions lead to discomfort and limitations in everyday activities that negatively affect quality of life and mental well-being [1]. Pain and associated stress can prolong the healing process.

A meta-analysis by Schmitz et al. concluded that extracorporeal shock wave therapy is an effective, safe and non-invasive treatment option for patients with musculoskeletal disorders [2]. It does not involve any medications or injections. As such, it is worth emphasizing that focused shock wave therapy can be used as an alternative to more invasive treatments such as cortisone injections or orthopedic surgery. It can also be used as an alternative to pain killers and other therapeutic options with potentially severe side effects. Our Focused Shockwave device enables the treatment of pathologies located up to 12 cm deep in the skin. This unique capability allows us to treat deep and calcified musculoskeletal lesions, trigger points, myofascial pain syndrome, nonunion fractures and enthesopathies resistant to healing. 

A review of the PEDro (Physiotherapy Evidence Database)  – the reference database for randomized clinical trials (RCTs), systematic reviews and clinical practice guidelines in the field of physiotherapy – indicates that 66 RCTs (out of 81) using Focused Shock Waves Therapy resulted in statistically significant positive outcomes for patients [3].

Below is a selection of the most notable effects achieved with FSWT. A study by Rompe et al. [4] on the impact of focused extracorporeal shock wave therapy (FSWT) and local anesthesia on treatment of plantar fasciopathy found that:

• a significantly greater number of patients treated exclusively with focused shock waves achieved a more than 50% reduction in pain at 3 months follow-up compared to patients receiving combined therapy with local anesthesia (67% FSWT only vs. 29% FSWT + local anesthesia). Studies by Lee et al. [5], Kim et al. [6] and Chen et al.
• [7] demonstrated the utility of FSWT in disabling pain due to knee osteoarthritis with a combination of FSWT and conservative physical therapy resulted in better clinical outcomes than conservative physical therapy alone.  Patients reported a significant improvement in the range of motion of the knee joint.

Data published by Cacchio et al. [8] demonstrated the utility of FSWT in patients with hypertrophic long-bone nonunions:

• reduction in pain without adverse side effects;
• safe and efficient – a positive energy flux density of 0.4 mJ/mm2 appears to be sufficient for this indication;
• clinicians should opt for fESWT over surgery in the management of hypertrophic long-bone nonunions.

Therapeutic shock waves: the sound of healing – but how are they created?

Let’s start with some basic definitions: shock waves are mechanical acoustic waves characterized by propagating disturbance that moves faster than the local speed of sound in the medium [9]. It is associated with a sudden rise from ambient pressure to its maximum pressure. In general, extracorporeal shock waves are characterized by the development of pressure over time.

How do focused extracorporeal shock waves act on the musculoskeletal system?

Extracorporeal shock waves are known to generate cavitation within the treated area [10]. Cavitation means the rapid formation, expansion, and forceful collapse of gas bubbles in liquids and is associated with rapid pressure changes [11]. Cavitation plays an important role in mediating the molecular and cellular mechanisms of action within the musculoskeletal system [10].

The DolorClast® Focused Shock Waves device uses piezoelectric technology. In simple terms, this means that a large number of piezocrystals are contained in the bowl-shaped handpiece. When rapid electrical discharge is applied, these thousands of piezocrystals react with a pattern of deformation (contraction and expansion). This is known as the piezoelectric effect: when electricity is passed through the crystals, they ‘squeeze themselves’ by vibrating back and forth. Piezoelectricity (or the piezoelectric effect) is the appearance of an electrical potential (i.e. a voltage) across the sides of a crystal when it is subjected to mechanical stress (i.e. squeezed). This induces an acoustic pressure pulse in the surrounding environment that can steep into a shock wave. When focused shock waves are generated using piezoceramic materials, this avoids mechanical displacement of the handpiece on the skin and prevents the need for treatment to occur under excessive pressure. The end result is that shock waves are focused and dispersed within the tissues. This highlights another important feature of DolorClast® Focused Shock Waves: that they can be used in patients with low pain thresholds.

How is the sensation of pain generated in the human body?

First, it is detected as sensory information by nociceptors located on free nerve endings; then, it is carried via A-delta and group C nerve fibers from the periphery to the dorsal horn of the spinal cord. This transmission of pain information is mediated by a number of neurotransmitters. Here, we will focus on one of them: substance P [12]. During shockwave therapy, an increased level of substance P [12] is also what is responsible for any discomfort or unpleasant sensations. Substance P and other neuropeptides are released from the peripheral ends of sensory nerve fibers and result in a slight sensation of pain [13]. Herein lies the answer! The longer the C-fibers are activated with shockwaves, the lower the concentration of substance P within the treated area. As a result, the nociceptors are no longer sufficiently stimulated. Less substance P in the tissue leads to pain relief (because the transmission between injury and brain is ineffective) and inhibits the neurogenic inflammation process [12, 14].

This effect can be explained in layman’s terms using the example of red chili peppers, which contain capsaicin. At first, the substance overwhelms the C-nerve fibers responsible for the sensation of burning in the mouth. However, after a couple of minutes, the feeling disappears and the tongue becomes numb. Anyone who has ever tried hot peppers should be familiar with this experience! Shock waves act on the musculoskeletal system via a number of molecular and cellular mechanisms.

1. They lower the substance P concentration and bring about pain relief.
2. They block the neurogenic inflammation process that plays an important role in the pathogenesis of tendinopathies (such as tennis elbow or plantar fasciopathy).
3. They activate the formation of primary muscle cells (to repair damaged muscle fibers) and increase expression of the following growth factors:

VEGF (Vascular Endothelial Growth Factor), which plays an important role in angiogenesis. It promotes the formation of new blood vessels and accelerates tissue healing [15,16,17,18],

PCNA (Proliferating Cell Nuclear Antigen) and eNOS (Endothelial Nitric Oxide Synthase), which are the growth factors responsible for stimulating blood circulation. An improved flow of oxygenated blood promotes tissue regeneration [15,19,20,21].