Extracorporeal shock wave therapy

This article explains therapy in orthopedics; for kidney stone fragmentation (ESWL) see description under kidney stones .

Device for radial extracorporeal shock wave therapy for orthopedics (example)

Device for focused extracorporeal shock wave therapy (example)

Shock waves are high-energy pressure waves that are similar to sound waves , but differ significantly in terms of energy, rate of rise and propagation, and the type of propagation.

Application areas (overview)

Kidney stones have been successfully treated (smashed) using extracorporeal shock wave lithotripsy (ESWL) since 1980 .

Since 1989, shock waves have also been used to treat bone fractures with delayed healing ( pseudarthroses ) and with lower energy for tendon insertion complaints such as epicondylitis , heel spurs or calcified shoulder and many other indications.

Since around 2010, extracorporeal shock wave therapy has also been used in urology to treat erectile dysfunction : the application of shock waves stimulates neo- angiogenesis , i.e. the formation of new blood vessels, which leads to better blood flow to the penis and thus a higher quality erection should lead.

method

As with ESWL, a generator generates structure-borne sound waves that are only bundled ( focused ) deep within the body . This compression of the shock waves can lead to the disintegration of a solid, for example calcification , particularly in the case of a pulse train . The lime deposit is ground into the finest particles by the shock wave treatment, then absorbed by the body and transported away by the bloodstream and excreted.

Originally, shock waves were generated by an electric spark discharge under water (see also hydroelectric conversion ) and focused in the therapeutic area by means of a semi-ellipsoid. This method of generating shock waves (electro-hydraulic shock wave) dates back to the 1970s and was introduced to remove kidney and gallstones without surgery. In the 21st century, it is established as a standard alongside electromagnetic and piezoelectric shock wave generation.

In the case of piezoelectric shock wave generation, the inverse piezo effect is used: Piezoceramic elements arranged on a concavely curved support are briefly expanded in the micrometer range by a high-voltage pulse and generate a pressure pulse. The piezo elements are precisely aligned with the therapy focus. Precise focussing and non-linear propagation of the impulse result in shock wave formation due to splitting in the treatment focus. It is a direct focus and does not require an additional reflector. Another method is to arrange the piezo elements flat and to stimulate them with time-delayed pulses in such a way that the sound waves meet in one place. This method based on the principle of the phased array antenna is also used in sonography to focus and pivot the beam. This technology enables a flat design of the pulse source as well as a precise, easily malleable focus zone. Up until now, it was only possible to generate pulse shapes directed to a point or defocused, this generation principle can also shape the shape of the sound field / focus in a linear manner.

The generation of electromagnetic shock waves is based on the physical principle of electromagnetic induction, comparable to the generation of sound in a loudspeaker. The coil and membrane are optimized in such a way that particularly powerful, short acoustic impulses are generated. When current flows through, magnetic fields form around the turns of the coil, which act through the insulation layer into the membrane. The rapid increase in current has the consequence that eddy currents are induced in the membrane , which are directed opposite to the originally present magnetic field. The resulting repulsive forces push the membrane away from the coil. The resulting pulse wave can then propagate to a transmission medium (e.g. water).

Point-like focusing and linearly focusing shock wave

execution

The calcification is made visible by means of an X-ray and the focus is set. The patient is on an examination table, the affected body region lies in a cutout of the table on a soft, semicircular plastic cushion that is filled with water. The shock waves introduced into this cushion, which are introduced, for example, by piezocrystals arranged in a semicircle or by wave reflection on a semi-ellipsoid, continue in the aqueous medium and are concentrated in one point, in the center of the calcification. Other body structures that are in the vicinity of the calcification (for example blood vessels , nerves , tendons ) are captured by the shock wave, but not damaged because they are not in the focus of the shock wave. A single shock wave can be heard as a loud sound and is perceived as a blow, like a small hammer blow. The frequency of the impact is around 60–300 per minute, the impact strength can be adjusted to the calcification.

In the case of treatments close to the surface, for example in the case of leg ulcers , the shock waves are not focused, but are introduced into the therapeutic area over a wide area. This requires a strong energy source, as the entire energy of the shock waves is distributed over a larger area and thus becomes weaker. In order not to lose the effect, however, it must be ensured that shock waves can reach the diseased cells with sufficient pressure in the entire therapy area. In addition to the defocused shock waves, the linear focusing piezo shock wave is also used here.

Benefit assessment

With tennis elbow , heel spur and calcified shoulder , the IGeL monitor of the MDS ( Medical Service of the Central Association of Health Insurance Funds ) has assessed three indications for extracorporeal shock wave therapy (ESWT) in Germany and has come to different results:

• The ESWT in tennis elbow and other muscle attachment problems is rated as “tending to be negative” (indications of minor benefit and evidence of minor damage).

• The ESWT for heel pain, on the other hand, is rated as “generally positive” (evidence of benefit and evidence of minor damage).

The "generally positive" evaluation of the ESWT for heel pain has led to the fact that the service is recognized as a health insurance benefit in Germany after a renewed assessment and consultation in the Federal Joint Committee : Since January 2019, the costs have been covered by the German statutory health insurance companies. The ESWT for heel pain is therefore no longer an individual health service ( IGeL ).

• The ESWT in the calcareous shoulder is rated as “unclear” (indications of a benefit, evidence of minor damage).

Unwanted side effects

In addition to bruising , swelling or superficial bleeding may occur. Short-term intensification of pain in the treatment area is reported less frequently. Incorrect handling can damage bony structures, blood vessels, nerves or tendons with early and late effects.

The pain felt during the treatment is perceived to different degrees, readiness for anesthesia is maintained in case the pain becomes too severe. If the initial symptoms have not improved significantly after three sessions, the therapy should not be continued.

In Germany, ESWT as a therapy for complaints in the field of orthopedics is not considered to be a service provided by statutory health insurances. The patient has to bear the costs of the treatment himself. An exception to this is ESWT for heel pain from 2019.

There are also treatment failures with ESWT and cases in which the symptoms worsen after treatment. It therefore requires careful determination of the indication and the use of an experienced doctor or therapist.

Web links

• Extracorporeal shock wave therapy (ESWT) (PDF; 934 kB) Federal Committee of Doctors and Health Insurance Companies. Summary report of the Medical Treatment Working Committee of the Federal Committee of Doctors and Health Insurance Funds on the deliberations in 1998 on the evaluation of extracorporeal shock wave therapy (ESWT) for orthopedic, surgical and pain therapy indications in accordance with Section 135 (1) SGB V
• Extracorporeal shock wave therapy for the calcified shoulder. IgeL-Monitor, May 31, 2013, updated September 19, 2014; published by the medical service of the Central Federal Association of Health Insurance e. V. (MDS)
• Physical basics of shock wave therapy (PDF; 607 kB)

Individual evidence

1. ^ Zhihua Lu, Guiting Lin, Amanda Reed-Maldonado, Chunxi Wang, Yung-Chin Lee: Low-intensity Extracorporeal Shock Wave Treatment Improves Erectile Function: A Systematic Review and Meta-analysis . In: European Urology . tape 71 , no. 2 , February 2017, ISSN  1873-7560 , p. 223–233 , doi : 10.1016 / j.eururo.2016.05.050 , PMID 27321373 .
2. ^ Anne B. Olsen, Marie Persiani, Sidsel Boie, Milad Hanna, Lars Lund: Can low-intensity extracorporeal shockwave therapy improve erectile dysfunction? A prospective, randomized, double-blind, placebo-controlled study . In: Scandinavian Journal of Urology . tape 49 , no. 4 , 2015, ISSN  2168-1813 , p. 329-333 , doi : 10.3109 / 21681805.2014.984326 , PMID 25470423 .
3. ↑ IGeL monitor, evaluation of shock wave therapy in tennis elbow , accessed on October 11, 2018.
4. ↑ ^{a b} IGeL monitor, evaluation of shock wave therapy for heel pain , accessed on October 11, 2018.
5. ↑ IGeL-Monitor, evaluation of shock wave therapy in the calcareous shoulder , accessed on October 11, 2018.
6. ↑ Side effects ( Memento of September 26, 2008 in the Internet Archive )

This article is about a health issue. It is not used for self-diagnosis and does not replace a diagnosis by a doctor. Please note the information on health issues !