2 The procedure
2.1.1 Extracorporeal shockwave lithotripsy (ESWT) is used to treat calcific tendonitis, where crystalline calcium phosphate is deposited in a tendon. This most commonly occurs in the shoulder joint, specifically in the supraspinatus tendon of the rotator cuff. When calcific tendonitis is symptomatic, it may present as chronic, relatively mild pain in the shoulder, with sporadic episodes of pain radiating down the arm or to the neck, with mechanical symptoms or with severe acute pain due to an inflammatory response.
2.1.2 Treatment for calcific tendonitis includes non-steroidal anti-inflammatory drugs, corticosteroids, physiotherapy, aspiration or lavage.
2.1.3 For patients refractory to these approaches, open or arthroscopic shoulder surgery may be offered. ESWT is a non-invasive alternative to these types of surgery.
2.2.1 ESWT involves giving controlled, short-duration sonic pulses to produce transient pressure disturbances, which fragment calcific deposits.
2.2.2 ESWT is an established technique for the treatment of renal calculi.
2.3.1 Four studies all showed an increase in function and a reduction of pain, but the effect of the dose of energy used on efficacy outcomes is unclear. For more details refer to the sources of evidence section.
2.3.2 The Specialist Advisors considered that the efficacy of ESWT is uncertain, particularly in relation to the dose of energy used. There are no registries and no trials are currently being performed.
2.4.1 Few complications were reported in the reviewed literature, and the most common was subcutaneous haematoma. It is not known whether this is because complications are uncommon or because complications were not well reported in the studies reviewed. For more details refer to the sources of evidence section.
2.4.2 The Specialist Advisors thought that pain during the procedure was the main potential adverse effect. They stated that the severity of the pain varied, but that studies showed that more than 80% of patients experienced significant pain. A single case of aseptic necrosis of the humeral head was reported by one Specialist Advisor.