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Even as the issues of fitness and well-being are being probed under newer concepts and technologies, short-wave diathermy (SWD), the old hand in providing relief from pain, is drawing renewed interest of the healthcare practitioners in its new avatar. It is a form of radio-frequency radiation that operates at 27.12 MHz, and is used therapeutically by physiotherapists (Wang et al., 2007).

SWD is the clinical application of electromagnetic energy where it gets converted into thermal energy. The most common benefits derived from it include relief from pain, contracture management, and the effect of enhanced blood flow to the localized region. In other words, its deep tissue heating process increases blood flow, metabolic rate, oxygenation, and concentration of white blood cells and antibodies, while decreasing inflammation and edema. Alongside it provides relaxation and relief from muscle spasm, and increases pliability of collagenous tissues. Therefore it is useful in many painful conditions like arthritis, bursitis, tenosynovitis, fibrositis, myositis, sprains, strains, fractures, neuritis, peripheral vascular disease, pneumonia, bronchitis, otitis media, pelvic inflammatory disease, chronic wounds, lymphedema, chronic fatigue syndrome, fibromyalgia, postsurgical pain and edema (Bernal, 2009).

Background
In spite of its vast potential in providing relief from pain, SWD could not become popular in the 1990s mostly due to two reasons like safety and high cost. The early units were capacitance-electrode machines that caused burns in some cases. Apart from that, some researchers also reported the instances of negative interaction of SWD with the implanted device, which caused severe brain damage in the area where the lead electrodes were implanted (Siberstein, 2008).

Thus apprehension of negative side effects like above influenced the physiotherapists and athletic trainers to find an alternative arrangement through ultrasound therapy (Merrick, 2001). However, the improvised versions of SWD that contains improved shielding and space plates are found to be safer and capable of providing a number of other positive side effect, besides proving to be far more effective than ultrasound therapy.

Reason behind Resurgence of SWD
The resurgence of SWD has become possible mainly due to two factors like shortcomings of ultrasound therapy and the increased strength of SWD. A brief comparison would clear the issue.

Ultrasound can heat only a relatively small volume of tissue, which is approximately twice the area of the machines sound head. Consequently, it cannot increase tissue temperature beyond the depth at around 1-5 cm. In the process it heats a volume of tissue not more than the size of two rolls of 35-mm film. This happens to be just a frugal part of the total volume of the body part that requires treatment. This clearly shows the limitation of ultrasound therapy. On the other hand, SWD heats a volume of tissue similar to the volume of a full-sized bowl within the same amount of time (Merrick, 2001) and generating more relief.

Clinical Grounds
Researched evidences also corroborate the above fact. Previous clinical research on its impact on the cellular level showed that under specific conditions (pulsed at a mean power of 48 W for 10 minutes twice daily on days 2, 3 and 4) of SWD exposure, the proliferation rates of dermal fibroblasts and chondrocytes were increased significantly (Hill et al., 2002).

The new clinical research of Wang et al. (2007) investigated on the impact of SWD on chondrocytes. Chondrocytes are specialized cells, which produce and maintain the extracellular matrix of cartilage, a tissue that is resilient and pliant (Muir, 2005).

It has long been recognized by the researchers that mitogen-activated protein kinases (MAPK) pathway is one of the most important area of study in pain management, since it gets deregulated in various diseases, ranging from cancer to immunological, inflammatory and degenerative syndromes and, therefore commands high-level protection. Several MAPK and receptor-tyrosine kinases have been characterized as participating in chondrocyte signaling pathways (Hoffman, Weston, and Underhill, 2003).  There are three major families of MAPK, such as extracellular signal-regulated kinase (ERK), c-Jun NH2-terminal protein kinase (JNK) and p38 (Orton et al., 2005).

Accommodating the significance of MAPK in the proliferation of different cell types, Wang et al. (2007) explored the role of all the above three major types of MAPK. In the process they found the phosphorylated ERK (phospho-ERK 1 and ERK 2) level increased significantly within 5120 minutes, following consecutive exposure to SWD for 7 days. On the other hand, exposure to SWD failed to alter the intensity of phosphorylated JNK and p38 within 0240 minutes. Cells were exposed to short waves once for seven consecutive days in the presence of 0, 10 mmolL, 20 mmolL or 50 mmolL PD98059 (an ERK inhibitor), where PD98059 totally inhibited SWD-induced enhancement of proliferation without altering normal control viability. In the presence of SWD and PD98059, the cell viability was lower than the normal control.

Wang et al. (2007) eventually found that cells exposed to SWD once per day for seven consecutive days produced 42 percent increase in proliferation, which is significant by no means, and which led them to the conclusion that SWD could increase proliferation in human chondrocytes by activating the ERK pathway, which is also involved in maintaining normal cell proliferation under physiological conditions. Thus this investigation clinically explains the advantages of SWD exposure in inducing recuperation of cartilage.

Other Benefits
SWD also provides a number of positive side effects, such as inhibition of inflammation, stimulation of connective tissue and bony repair. It has also been reported that joints appear to increase both uptake and concentration of glycosaminoglycans, glucosamine, and galactosamine, the key structural elements of articular cartilage, when SWD applied to healing. Such developments, therefore, hold great promise for osteoarthritis patients (Merrick, 2001).

SWD can also be applied in the post-surgery conditions. Varying the amount of heat it can be used in special situations too, such as tissue warming, prevention of excessive bleeding, and sealing off traumatized tissues. Thus SWD can be an important tool in eye surgery and neurosurgery. It takes approximately 20 minutes for one application, though it may vary according to the gravity of the condition (Bernal, 2009).

Apart from providing a plethora of benefits, SWD is also easier to use in comparison with other heating modalities. It takes the application of basic heat (or thermography) therapy to a higher and more intense level, where the use of targeted short-wave electromagnetic pulses stimulates healing in deep tissue. On the other hand, standard heating modalities are less effective, as they do not penetrate the skin (Bernal, 2009).

Conclusion
The review above clearly shows that SWD stands to provide greater benefits than other heating modalities like ultrasound therapy, as it is capable of penetrating more to the troubled zones and providing relief in less time. Therefore, research findings on the efficacy of the new SWD machines justify its resurgence. However, a cogent and cohesive campaign is now needed to change the perceptions of the healthcare practitioners as well as the athletic trainers who still are apprehensive of negative side effects of SWD. Alongside, lowering the cost of SWD units could also contribute to its promotion.