The Management Of Soft Tissue Biology Essay

My objectives include, reviewing literature on the biological and physical effects of ultrasound to obtain a conclusion whether therapeutic ultrasound treatment is effective on soft tissue injuries. I will also include the two primary types of benefit of thermal and non-thermal effects therapeutic ultrasound achieves. Furthermore, I will discuss the effects on the healing and repair process from the outcomes of ultrasound on calcific tendinitis.

My methodology involves a literature search using research and studies from allied health care databases such as MEDLINE, CINAHL, and Cochrane. The terms used in my search were "therapeutic, ultrasonic therapy, and calcific tendonitis", as well as mesh headings to specify and simplify my results. My generic limitations included English literatures, human studies, and research found between 1946- 2013.

Ultrasonic therapy is another term used for ultrasound and is a form of electrotherapy applied to mobilise collagen tissues, remove oedema and reduce pain. (REF) Calcific tendinitis is a soft tissue pathology, common in the supraspinatus tendon. "Therapeutic" is a term used to promote a sense of well-being and relaxation (British Red Cross 2013).

Ultrasound is a form of acoustic energy consisting of high frequency sound waves, or mechanical vibrations which may produce thermal or non-thermal effects upon the tissue (William E. 1994). Waves are created through a generator producing an electrical current converted to acoustic energy, located within the transducer through a piezoelectric crystal (A. Arnau 2004).When exposed to the current, the crystal vibrates dependent on the given frequency which then expands and contracts producing the wave (J. L. Rose 1999). Propagation occurs during transmission of the waves, with a progressive loss of the intensity of the energy during passage through tissue (attenuation) (Kozhikode 2011). This is due to absorption, dispersion, or scattering of the wave (C.A Speed, 2001).

The therapeutic effects of ultrasound are divided into thermal and non- thermal effects. According to Lehmann (1982), ultrasound can produce the desirable effects of therapeutic heat. These non-thermal effects may include "increased blood flow, reduction in muscle spasm, an increase in extensibility of collagen fibres, and increased blood flow" (C.A speed 2001). Ultrasound selectively increases temperature in tissues due to the mode of action. If the temperatures of the damaged tissues ascend to 40-45 degrees, a therapeutic effect is created with the result of hyperaemia (Prentice WE.1994). In addition, "temperatures in this range are thought to help in initiating the resolution of chronic inflammatory stages" (Dyson & Suckling 1978). However, it is suggested excessive thermal effects may damage the tissues with higher ultrasound intensities (Dyson. M 1987).

To determine the parameter for ultrasound’s thermal effects, the duty cycle can be adjusted to a continuous or pulsed mode. Pulsed mode, ratio of 1:4 has more effectiveness in treating calcific tendinitis as it produces non-thermal effects (Amir H. Barati). Non-thermal properties of ultrasound include micro-streaming and cavitation, resulting in biophysical effects without the production of heat. (C.A Speed 2001). Cavitation is the form of gas filled bubbles that expand and compress due to ultrasonically induced pressure changes in the tissue fluids (Josza L. 1997). As a result, there is an increase in flow in the surrounding fluid.

Micro-streaming is the development of unidirectional flow currents in fluids along cell membranes (Shi, X. et al. 2001). This occurs due to mechanical pressure change within the fields of ultrasound. Cell membrane structure, function, and permeability is altered during micro-streaming (Dyson M. 1987), suggested to stimulate tissue repair (Dyson M. Sucking J. 1978). Effects of cavitation and micro- streaming include stimulation of fibroblast repair and collagen synthesis, and tissue regeneration.

It has been reported that the non-thermal effects of ultrasound are more important in the treatment of soft tissue lesions than are thermal effects (Dyson M, Suckling J. 1978).

According to Christopher et al, acute injuries are treated best with non-thermal application to "improve cellular permeability, increasing macrophage activity, and enhancing protein synthesis". Ultrasound has been recognised for its therapeutic effects of cavitation, micro-streaming, and stable and unstable bubble formation, to enhance tissue healing. Furthermore, the application of ultrasound to damaged tissues will amongst other things, "speed the rate of healing & enhance the quality of the repair". (Watson 2006).

In calcific tendinitis, the supraspinatus area becomes inflamed, accumulating damaged tissues, whilst blood vessels become blocked causing swelling and pain. During ultrasound treatment of calcific tendinitis, sound waves bounce against the tissues scattering the fluid that causes inflammation. As a result, regular blood flow is facilitated, furthermore increasing its flow, removing dead cells and toxins from the injured tissue, hence enhancing the body’s natural healing process (E. P. Papadakis 1999).

More specifically, Mortimer AJ and Dyson M. (1998) found that ultrasound stimulates resorption of calcium deposits during tissue healing and repair. They reported "it stimulates the accumulation of peripheral blood cells by activating endothelial cells". During this process, migrating macrophages are involved in phagocytosis of calcified particles.

Terkeltaub et al 1991 described the disruption of microcrystals in the supraspinatus tendon may be triggered or accelerated by ultrasound at higher intensities. He proposed macrophages are then stimulated during the process of phagocytosis, removing calcifications in the presence of the smaller calcium crystals. nikFinally, temperature increases of the tissue exposed to ultrasound may "increase blood flow and induce hyperemia and metabolism, thus facilitating the disintegration of calcium deposits" (Ebenbichler 1999).

Rahman et al (2007) conducted a study of 26 patients to determine the effects of ultrasound therapy (UST) on calcific tendinitis. UST was applied for a duration of ten minutes with an intensity of 1 to 1.5 W/sq cm. As a result, all 26 patients became free from pain and restriction of movements after 12 doses of UST. It was reported 92% of cases showed no calculi in radiograph data. Due to the improvement in patients, It is evident this non-invasive modality of treatment may have caused therapeutic effects on the tissue healing and repair process in the supraspinatus tendon with calcifying tendinitis.

The therapist administering ultrasound can target tissues at different depths by simply using a different frequency. Therapeutic ultrasound has a frequency range of 0.75 to 3 MHz with most machines set at 1 or 3 MHz (William E. 1994). In relevance to calcific tendinitis, the rotator cuff tendon consists of deep tissues requiring an output frequency of 1MHz. The lower the frequency used, the deeper the penetration of the waves into the body (Great Lakes). As the ultrasound beam penetrates further into the tissues, a greater proportion of the energy will have been absorbed, resulting in less energy available to achieve therapeutic effects.

Consequently, 1MHz is recommended for deeper injuries, whereas a frequency of 3MHz is suggested for more superficial lesions at depths of 1-2 cm (C.A Speed, 2001). To determine the parameter for ultrasound’s thermal effects, the duty cycle can be adjusted to a continuous or pulsed mode. Pulsed mode, ratio of 1:4 has more effectiveness in treating calcific tendinitis as it produces non-thermal effects (Amir H. Barati).

On the other hand, Weinstein 1986 conducted a study involving 20 patients with supraspinatus tendinitis. A double blind trial using sham ultrasound was implemented against the real treatment to gather whether the patients reported back with improvements. His findings showed data of the outcomes physiological effects should have on the soft tissue injury including;

"Augmentation of blood flow, increased capillary permeability and tissue metabolism, enhancement of fibrous tissue extensibility, elevation of pain threshold, and alteration of neuromuscular activity leading to muscle relaxation".

Weinstein (1986) hypothesised the result of these effects on the inflamed, sore and stiff shoulder with tendinitis may be a promotion of healing, reduction of muscle spasm, reduction of pain, and increased range of motion. However, concluding his studies and results, it was found other treatments were more effective on shoulder pathologies such as tendinitis than ultrasound alone.

Analysing data from various journals and sources raises the question whether therapeutic ultrasound is effective in soft tissue injuries or not. Evidence surrounding ultrasound treatment on calcific tendinitis has shown to be effective in treating patients when measuring their overall health statuses. Although ultrasound therapy is used to treat calcific tendinitis of the shoulder, its efficacy has not been rigorously evaluated.

From reviewing literature on the tissue healing and repair effects of ultrasound, it was found

understanding the depth of the tissue being treated, as well as the frequency required for the energy source to penetrate to the proper tissue depth could certainly enhance therapeutic ultrasound effectiveness (Paul Higgins).

It is evident ultrasound application over the affected soft tissue area, aids the reduction of swelling quickly in addition to increasing blood flow to the area allowing quicker tendon healing.