Physical basics

Shock waves are acoustic pressure waves of extremely short duration. Their physical strength is given as energy flux density (mJ/mm2). Through various methods, it is possible to generate the greatest effect of a shock wave by focusing the tissue to be treated in depth (focused shock wave). The shock wave introduced into the body releases its energy in the body when it strikes tissue types with different acoustic resistance (soft bone tissue; soft calcium tissue). Tissue types with acoustic properties similar to those of water penetrate the shock wave without any damaging influence (skin, muscles, fat, etc.)

Technical implementation

The technical implementation of shock wave treatment is simple in most cases. The therapy head is coupled to the skin of the area to be treated with a contact gel and the energy flux density and number of pulses are adjusted. The shock waves are then applied at a frequency dependent on the energy flux density.

Especially the first pulses are painful for the patient when the shock waves hit the inflamed tendon tissue. Anesthesia or other anesthesia is usually not necessary, however. The pain usually improves in the course of the therapy.

Depending on the number of shock waves emitted, a therapy session lasts only between 5-15 minutes for tendon attachment disorders. 2-5 sessions are the rule. The therapy of pseudarthrosis and femoral head necrosis differs from this.

A higher energy flux density is used and only one session takes place. A form of anaesthesia is usually used.A target system is necessary for calcified shoulder as well as for pseudarthrosis and femoral head neoplasia treatment. Usually, the adjustment of the therapy head is done with the help of X-ray fluoroscopy. A target system is not necessary for the other diseases. One orients oneself both on the pain and on anatomical landmarks.

Fields of application of shock wave therapy

In diagnosing heel spurs, the first step is to try to alleviate the symptoms by immobilising, cooling and special insoles in combination with painkillers. If these approaches do not have the desired effect, a shock wave therapy against a heel spur can be performed. This is an outpatient treatment in which the foot is exposed to short, high-energy ultrasound pulses which are transmitted through water.

The sound waves are also simply transmitted through the soft body tissue, i.e. muscles and fat, until they hit solid tissue, such as bone. This tissue is then set into vibration and made unstable. Usually about three treatments are necessary at intervals of two to four weeks.

In the case of the heel spur, this means that the shock waves penetrate the skin on the heel, the underlying fatty tissue and the lower leg and foot muscles until they hit the bony heel spur. Here the energy of the waves is then discharged and the heel spur is set into vibration, which leads to instability. Eventually, the high energy causes the heel spur to be mechanically shattered.

The parts that have detached themselves must then be broken down by the body itself. To achieve this goal, it is necessary to bundle the shock waves in such a way that they are only directed at the heel spur but do not damage the heel bone. Medium to high-energy beams are used to treat a heel spur.

Focused shock wave therapy is recommended because it has proven to be more effective than radial shock wave therapy. Depending on the cause of the heel spur, shock wave therapy of the heel spur can cause corresponding side effects. If there is an inflammation, either of the bursa or the tendon plate on the underside of the foot (plantar aponeurosis), shock wave therapy may cause pain to the patient during the first treatments.

In this case, it is recommended to use a local anesthetic (local anesthesia). Overall, however, shock wave therapy is considered a variant with comparatively few side effects. However, shock wave therapy of the calcaneal spur also has positive side effects.

If the waves hit inflammation, they have a healing effect, because they stimulate repair mechanisms and lead to the formation of new blood vessels. A follow-up treatment is usually not necessary. If there is an aggravation of the pain at the beginning of the treatment, it can initially be alleviated with anti-inflammatory medication and should regress in the further course of the treatment.

Overall, shock wave therapy of the calcaneal spur has good chances of success and is a good alternative that can be preferred to surgery on the calcaneal spur. Also in the case of the so-called tennis elbow, the epicondylitis humeri lateralis, immobilization and cooling of the elbow in combination with anti-inflammatory medications are of primary importance. If this does not improve the symptoms, alternative forms of therapy must be considered, for example with botulinum toxin (Botox) or even surgery.

However, before these approaches, which are rich in side effects, are carried out, a shock wave therapy can be initiated. This is often carried out in conjunction with physiotherapy. Two effects are achieved by the high-energy shock waves that are transmitted through the tissue to the inflamed tendon attachment.

Because tennis elbow does not require the mechanical destruction of bony structures, low-energy shock waves are used here. The treatment is usually painless, but is felt differently from patient to patient and in some cases requires a local anaesthetic. Since small nerves and blood vessels run in the area of the elbow, these too can be damaged by the shock waves.

This can cause bruising, which disappears after a few days. Shockwave therapy has a high success rate of 60 to 80% in the treatment of tennis elbow.The earlier this therapy is started, the greater the chance of alleviating the inflammation and the existing complaints and to heal completely in the long run. Just like the Botox treatment, the shock wave therapy of tennis elbow has to be paid for by the patient in most cases.

Only private health insurance companies cover the treatment in some cases.

On the one hand, the tissue damaged by the inflammation at the tendon attachment of the forearm extensor muscles is destroyed by the shock waves and can then be broken down by the body.
On the other hand, the body’s own healing process, i.e. the reduction of inflammation, is stimulated and blood circulation is increased.

One speaks of a calcified shoulder when small lumps of calcified tissue are deposited on the shoulder muscles’ attachment tendons. This can lead to very severe shoulder pain because the calcium deposits cause a lot of friction on other structures.

In technical terminology, the calcified shoulder is called tendinosis calcarea. Shock wave therapy of the calcified shoulder should only be carried out when conservative treatment options, such as cooling or anti-inflammatory treatment with ointments or medication have no or insufficient effect. In this case, the initiation of shock wave therapy is preferable to surgery, as the risks and side effects are significantly lower and no general anesthesia is required.

One exclusion criterion for shock wave therapy, however, is if there is a tear in the rotator cuff, i.e. the muscles around the shoulder. Shock wave therapy is most frequently used for the calcified shoulder. It has also proven to be the most successful therapy for this condition.

Also in the shoulder area, the shock waves are focused on the affected areas in advance so that the high-energy waves do not destroy the surrounding tissue. The calcification must be localized with the help of ultrasound or X-rays before the therapy is carried out. Medium-energy waves are used for the treatment of the calcified shoulder, since they have to penetrate the tissue here more deeply than at other locations.

The shock waves penetrate to the calcification and lead to its destruction. The lime particles that are produced are absorbed and excreted by the body. Even in the natural course of disease of the calcified shoulder, the lime deposits often dissolve.

However, this can be shortened by shock wave therapy and the symptoms subside more quickly. The shock wave treatment can cause pain to the patient. In this case a local anesthesia should be applied.

After the shock wave therapy of the calcified shoulder, the patient should rest his shoulder for one or two days. This means that work where the hands have to be raised above the head should be avoided. Overall, the pain caused by a calcified shoulder can be significantly relieved by shock wave therapy, thus increasing the mobility of the arms.

In the area of the Achilles tendon, shock wave therapy can be used in case of inflammation of the tendon (achillodynia). However, the therapy should first be tried out with the help of immobilization, painkillers and physiotherapy. If no improvement is achieved, shock wave therapy is an alternative or better an additional form of treatment.

In the course of the inflammation of the Achilles tendon, small calcium deposits are formed on the tendon. Sometimes these also lead to the formation of a heel spur, which can also be treated with shock wave therapy. After the shock waves have been focused on the inflamed and calcified area of the Achilles tendon, the shock waves are conducted away via water and penetrate the body tissue.

As soon as they hit solid tissue, they cause it to vibrate. This is the case with calcium deposits. When these are made to vibrate, they become increasingly unstable and are mechanically destroyed by the vibrations.

The smallest particles that are created can be absorbed and excreted by the body itself. A treatment session usually takes about 5 to 10 minutes. Shockwave therapy also has a positive effect on inflammation, as it stimulates the body’s self-healing processes.

Thus, pain that originates from an inflamed bursa or directly from the tendon is also increasingly relieved. In addition, the blood circulation in the irradiated area is stimulated by the formation of new vessels in this area.The highest healing rate of an inflammation of the Achilles tendon is achieved if, in addition to shock wave therapy, a special strength training for the Achilles tendon is carried out regularly. Shockwave therapy was originally developed for the treatment of kidney stones and gallstones.

Small stones can often be eliminated from the body itself by conservative methods, such as drinking a lot, exercise and heat. However, if this does not alleviate the symptoms, or if the kidney stone exceeds a certain size (8mm), another form of therapy should be chosen. Up to a size of about 2 to 2.5 cm, shock wave therapy has proven to be a successful treatment method.

The shockwaves are focused on the kidney stone and transmitted through the body. For this purpose, the exact position of the stone must be clarified beforehand by means of ultrasound or X-ray examinations. Since the stone has a solid structure in contrast to the surrounding tissue, it is excited and shattered by the waves.

The individual parts of the stone are then excreted through the urinary system. See: Smashing kidney stones A treatment takes about half an hour to an hour and usually does not require anesthesia. However, some patients find the shock waves in the area of the back painful.

In these cases a local anesthetic can be applied. However, shock wave therapy is not suitable for the acute treatment of kidney colic caused by the stone, but is carried out at colics-free intervals. However, it can happen that colic is caused by the fragmentation of the stone and the resulting stone fragments. This is the case in about every third patient. In addition, bruising can occur, since the mechanical impacts can cause minor injuries in the kidney area.