7. Shortwave Diathermy
When a deep heating effect is the desired physiological goal, then shortwave diathermy (SWD) is the logical choice. Since the 1940s, SWD has been a part of a standard physical therapy and one of the most popular forms of high-frequency electromagnetic radiation treatments. Included in this category of diathermy are ultrasound and microwaves, both of which have their own specific medical/surgical and rehabilitative applications. SWD is known to significantly increase temperature of deep soft tissues by increasing metabolic activity of collagen-based structures. The 1990s saw an enormous decline in the use of SWD, with fewer commercially available units being sold. With more recent research focusing on tissue oxygen saturation levels as being a critical indicator of tissue viability and an important predictor of optimal function, therapies that effectively increase tissue perfusion and O2 levels will be in demand (Table 1).
Strength of Treatment
There is no mistaking a diathermy session for anything else, and precautions and contraindications must be adhered to for safety reasons. This is a high-energy session that can cause tissue burns if dosimetry is not monitored carefully.
Ease of Treatment
There are some new or modern SWD configurations available in the application of diathermy, but the first- and second-generation units were rather cumbersome, with large plastic/metal electrode pads attached to swinging arms resembling the robot from Lost in Space. Those devices required special attention to EMF shielding of the coils, which led to the need for environmental precautions including distance requirements from pad to patient and pad to provider. Contemporary units are much safer and more user friendly.
Therapies that can be “felt” by a patient tend to have better adherence/compliance than those that are subliminal and perhaps require a greater leap of faith. It has been our observation that when patients are selected well for this treatment, they tend to stay with it and complete the course of therapy.
Diathermy units are not inexpensive by any means but generally cost under $10,000. Cost effectiveness will vary based on a number of factors, not the least of which will be practice type. Deep heating sessions tend to work well with more senior patients, who tend to have more deeply set conditions, including tendinopathy and arthropathies. As with any therapy, the cost-benefit ratio needs to be considered to justify the expense.
The research support for SWD tends to be older work that appeared in the literature; not much analysis has been done over the past 20 years. The clinical trials that exist seem to support a beneficial effect(s) for SWD, but clearly more research is needed. The empirical or observational evidence is vast, supporting excellent potential for improving perfusion and blood flow in the treated area. This would help explain the longevity of SWD usage despite a dearth of scientific evidence in the form of clinical trials.