Focused shock wave therapy (FSWT), an extracorporeal shock wave therapy procedure (synonym: ESWT), is a medical technique used to disintegrate and remove calcium concretions and to treat pain. The physical procedure, which originated in the treatment of kidney and gallstone disease, is now also used to treat orthopedic conditions such as soft tissue, joint, and bone disorders associated with chronic inflammation.
Indications (areas of application)
- Achillodynia (pain syndrome of the Achilles tendon)/attachment tendinopathy of the Achilles tendon.
- Dorsal heel spur/calcaneal spur – bony, thorn-like protrusion on the heel as a result of overuse of tendons.
- Epicondylitis humeri lateralis (synonyms: Epicondylaris humeri ulnaris; tennis elbow)/Epicondylitis humeri medialis (synonyms: Epicondylaris humeri ulnaris; golfer’s elbow).
- Fasciitis plantaris (fasciitis plantaris; plantar fasciitis; plantar fasciitis) – plantar heel spur / lower heel spur; is occasionally accompanied by inflammation of the plantar tendon on the sole of the foot (plantar tendonitis or plantar fasciitis).
- Haglundexostose – form variant of the calcaneus with calcification of the Achilles tendon attachment.
- Pseudarthrosis – delayed bone healing after a bone fracture with formation of a false joint (consolidation rates up to 70%).
- Supraspinatus tendon syndrome – usually inflammatory, degenerative changes in the shoulder area, which lead to pain.
- Tendinosis calcarea of the rotator cuff (calcified shoulder) – calcifications on the tendons of the muscles located at the shoulder joint.
- Tendinopathia patellae – Painful inflammation of the tendon apparatus in the area of the kneecap.
- Tendinitis trochanterica – Tendon irritation, often with accompanying bursitis in the area of the hip joint.
Contraindications
- Superficial inflammatory skin lesions – In cases of bacterial or mycotic (fungal) superficial inflammation, the use of shock wave therapy should be suspended initially until healing of the inflammation has occurred.
- Deep inflammatory skin lesions – In deep inflammatory processes such as bacterial phlegmon, shock wave treatment should not be applied in the surrounding area. Immediate (antibiotic and, if necessary, surgical) therapy should be sought.
- Malignant tumors – In the presence of malignant (malignant) tumors of the surrounding tissue should not be shock wave therapy.
Before therapy
Local anesthesia (local anesthetic) is not necessary when using low-energy shock waves. However, local or regional anesthesia, which may be associated with a short inpatient stay, should be administered when medium- or high-energy shock waves are used.
The procedure
Shock waves are high-energy waves generated in various technical ways, for example, by short pulses of pressure generated in water. This can be done using different physical principles:
- Electrohydraulic
- Piezoelectric (oscillations of quartz crystals).
- Electromagnetic
The sound pulses can be localized to a specific area and act there, that is, they develop their effect only at the programmed place of action or in the diseased area of the body. In extracorporeal shock wave therapy, the shock waves are generated outside the patient’s body (extracorporeal). In focused shock wave therapy, shock waves are first generated as divergent (differing) waves and then focused via a reflector in front of the applicator to treat the tissue (focused ESWT). When the focused shock wave impinges on tissue interfaces, for example between connective tissue and bone, the acoustic energy of the shock waves is converted into mechanical, chemical and thermal energy. Shock waves are differentiated according to their energy content, which can be varied depending on the application. The following list relates the energy content to various orthopedic indications:
- Low-energy shock waves – These shock waves are used to treat pain. The therapeutic principle is based on counter-irritation: the goal is to convert a chronic inflammation into an acute one.The shock waves cause controlled injury to the tissue (soft tissues, muscles, tendons), which leads to increased vascularization (vascular or blood supply) and promotes the healing process. Another effect is the hyperstimulation analgesia: this is a pain suppression by overloading the pain stimulus conduction.
- Medium-energy shock waves – The medium-energy shock waves favor the formation of cracks in calcium concretions, so that the body’s own degradation mechanisms can function again and the concretions can be broken down. This happens, for example, in the treatment of tendinosis calcarea (calcifications in the shoulder joint area).
- High-energy shock waves – These are used, for example, in pseudarthrosis (delayed bone healing after a bone fracture with the formation of a false joint) to stimulate osteogenesis (new bone formation). This is also done by controlled injury to the tissue.
Focused ESWT devices can be assumed to have a penetration depth of up to 12 cm.
After therapy
The duration of application and success vary for different indications. Multiple applications and additional procedures should be used as appropriate. In the absence of a response to therapy, use of more invasive procedures and adjunctive drug therapy must be discussed.
Potential complications
- Side effects of local and regional anesthesia – Because local or regional anesthesia is useful during treatment with medium- and high-energy shock waves, side effects may include cardiovascular dysfunction and other symptoms such as dizziness, perioral paresthesias (facial sensations), visual and speech disturbances (slurred speech), and muscle tremor, up to and including generalized seizure and coma with respiratory arrest.
- Side effects of shock wave therapy – Minor skin hemorrhages (skin bleeding) as well as arrhythmias (cardiac arrhythmias) during shock wave application are possible, but rarely to be classified as serious.
Benefits
Focused shock wave therapy is a successful and proven method for both the destruction and removal of calcifications and pain management. Patients benefit from the gentle procedure by avoiding surgery, reducing pain, and significantly increasing their performance.
