Description of Intervention
Electrical stimulation to relieve pain was first attempted by the early Greeks and Romans.1 In more recent times, iontophoresis treatment has developed into a process, using a small electrical gradient to move a medication, bioactive agent or other chemical across the skin. This therapy has been successful in some hand and arm treatments. However, studies have questioned the duration of improvements in patients, in comparison to the improvements with needle injection or splinting.2 Iontophoresis should be considered, in some patients, because it is non-invasive and may have less side effects than injections.3
Indications for Intervention
Candidates for iontophoresis may include patients with carpal tunnel syndrome, overuse syndrome, palmar hyperhidrosis, thumb basilar joint (CMC) osteoarthritis and lateral epicondylitis. Some patients may also need iontophoresis treatment after injury or surgery.
Diagnosis
- Ask for the patient’s medical history. Also record comorbidities, such as diabetes and rheumatoid arthritis (RA).
- Assess any changes in activities of daily living, including changes in playing a musical instrument.
- Check active range of motion in the hands and fingers. Evaluate any signs of inflammation or stiffness.
- If the patient shows symptoms of TMC osteoarthritis, check grip strength and key pinch.4
Intervention Options
For iontophoresis treatment, the therapist will need a chamber with positively or negatively charged solution of an active ingredient and its solvent, and polarized electrodes, which apply a similar charge polarity. Usually, the electrode’s charge is achieved with a low-voltage, low-amplitude direct current.2
Studies of treatment efficacy are inconclusive. Iontophoresis has produced positive results, on a short term basis. It allows lower doses to be administered than with injections, which reduces systemic effects, especially with overuse syndrome. With overuse syndrome and other chronic conditions, iontophoresis may help to reduce the need for NSAIDs and acetaminophen. However, for long term treatment, it may not have any advantages over injections.2 With lateral epicondylitis, it is unclear whether dexamethasone is reaching the affected tissues, or whether it is only the electrical stimulation that is influencing the patient’s reaction.3Iontophoresis may not be the ideal option for thumb TMC osteoarthritis. Some improvements have been shown after 3-6 months, but improvements with TMC osteoarthritis, over years or decades, may be due to a natural fluctuation of the symptoms.4,5 With palmar hyperhidrosis, patients have experienced positive outcomes, but the effects of treatment may only last a few months each time it is used.6
