Therapeutic ultrasound involves mechanical vibration at frequencies above the upper limit of human hearing (which typically falls at 16 kilohertz (Hz). This frequency range also encompasses natural sound frequencies.
Attenuation occurs when ultrasound waves strike body tissues and reflect off their surfaces before being absorbed by deeper layers.
1. Acute
Acute ultrasound therapy employs sound waves emitted at a high frequency that penetrate deep into tissues, producing acoustic vibrations that stimulate cells within them and promote healing and regeneration. Acute ultrasound therapy is considered safe, non-invasive treatment option suitable for many conditions and it’s generally advised that at least several sessions be undertaken over a few weeks before making a decision about treatments or therapy plans.
The therapist first selects a small area on the body for treatment and applies gel to help sound waves pass through it more easily. They then move their ultrasound probe across it in circular motions in order to cover as much tissue in as little time possible – usually without pain, but occasionally creating mild discomfort similar to muscle work outs.
Ultrasound therapy has proven itself effective at treating numerous conditions and injuries, from joint sprains and strains to tendonitis, plantar fasciitis and shoulder bursitis – and chronic conditions like plantar fasciitis or shoulder bursitis. People can feel relief after just one session while others require multiple weeks before starting to see results.
Ultrasound ultrasound waves produce vibrations which have both thermal and non-thermal effects on tissues. When high-frequency soundwaves hit soft tissue areas of your body, they can heat collagen for decreased inflammation and improved circulation.
Ultrasound therapy’s increased circulation can then help reduce swelling and relieve discomfort, as well as stimulate metabolism and aid with tissue repair.
To determine an adequate dose of ultrasound for their patient, a practitioner must take several factors into account, including frequency, intensity, mode and duty cycle if pulsed, size of treatment area as well as frequency/intensity/modality/duty cycle of pulsed devices.
The type of therapy selected also plays a key role in how quickly results become evident for patients. Acute injuries like muscle strains and ligament sprains tend to show improvement more quickly than chronic conditions like plantar fasciitis or rotator cuff tears.
2. Subacute
Therapeutic ultrasound utilizes the same principles of electrical energy being passed through a piezoelectric crystal that oscillates at ultrasonic speeds to create mechanical vibration (sound waves) which is transmitted into body tissues through metal treatment heads with hypoallergenic contact gel and transducers emitting waves through tissues. Therapeutic ultrasound can either produce thermal or non-thermal effects; its thermal effects include an increase in connective tissue elasticity, improved blood flow which improves delivery of oxygen and nutrients while flushing away waste products, as well as increasing cell wall permeability while stimulating protein synthesis.
Therapeutic ultrasound’s non-thermal effects are due to cavitation – the creation of microscopic bubbles in tissue. This mechanical stimulation changes how efficiently cells move nutrient molecules across their cell membrane and absorb shockwaves from shockwaves, speeding healing while decreasing pain by increasing extensibility of mature collagen (an essential constituent of tendons, ligaments and fibrous scar tissue).
At this subacute phase of tissue injury, therapeutic ultrasound can aid in the formation of new muscle fibers, promote local cell growth, boost production of ATP, and enhance protein synthesis. Furthermore, ultrasound therapy has also been found to decrease inflammation-provoking mediators released during this phase by decreasing mast cell degranulation.
Frequency of therapeutic ultrasound is important both thermally and non-thermally, with lower frequencies providing deeper penetration into tissue while higher frequencies diminish this effect but may affect surface tension and membrane permeability in cells.
Therapeutic ultrasound should generally be combined with other therapies when treating musculoskeletal injuries, and is most beneficial when applied during the subacute stage of injury. When combined with friction massage and stretching therapies – ideally while tissue is still warm from ultrasound treatments – therapeutic ultrasound treatment may prove particularly effective.
3. Chronic
Therapeutic ultrasound is an invaluable tool used by physical therapists to provide a mechanical vibration that encourages healing at a cellular level, helping reduce pain, increase tissue movement and decrease inflammation. It often forms part of an overall treatment plan to manage pain or accelerate injury recovery.
Therapeutic ultrasound uses a handheld device with piezoelectric crystals to generate sound waves, with an allergy-friendly contact gel applied directly onto the skin for maximum soundwave transmission into tissue layers beneath. As soundwaves penetrate tissue layers beneath, vibrations produce healing by altering cell activity and increasing protein synthesis; blood flow to treated areas also increases which facilitates increased nutrient delivery while breaking down any scar tissue formed from injury or chronic conditions.
Therapeutic ultrasound not only facilitates healing processes but can also relax tense muscles and restore mobility, providing relief to people suffering from conditions like plantar fasciitis, tendonitis or shoulder bursitis. Furthermore, ultrasound treatment has proven useful with other musculoskeletal issues like nerve entrapment associated with carpal tunnel syndrome.
The frequency and type of therapeutic ultrasound treatments will depend on both individual needs as well as the nature of ailment being addressed. Some conditions will see immediate improvements while others require longer-term plans before experiencing relief. It is wise to consult your physician and physical therapist prior to beginning any new therapies.
Your healthcare provider may suggest ultrasound therapy as part of your treatment plan, depending on your health insurance coverage. Ultrasound therapy tends to be more cost-effective and noninvasive than many medications or surgeries, making it an attractive solution.
However, ultrasound therapy should only be used in certain circumstances. For instance, it shouldn’t be applied directly on areas with active infections or cancerous lesions and it isn’t advised for people with pacemakers. Furthermore, ultrasound can cause complications with certain vascular conditions; so always consult a healthcare provider prior to commencing therapy.
4. Maintenance
The frequency and duration of therapeutic ultrasound treatment will depend on both the condition being addressed and its response from patients. Your physical therapist will work closely with you to find an ideal schedule and frequency of sessions tailored specifically to you and your condition. Your therapist may suggest 2-3 visits weekly over an extended period, which could range from several weeks up to several months or longer.
Therapeutic ultrasound delivers non-thermal effects through cavitation, microstreaming and acoustic streaming techniques, which have been found to stimulate cell membranes physically, leading to release of inflammatory mediators and speed up healing and promote tissue remodeling. The effects may also help facilitate the cellular repair process faster as well as speed healing overall.
As ultrasound waves pass through the body, they interact with tissues, bones, fluid and air. While part of its energy reflects off surfaces within the body while the rest is absorbed; its amount depends on frequency and intensity of waves. Therapeutic ultrasound works differently: continuous soundwaves increase blood flow to areas being treated while simultaneously providing more oxygen and other essential chemicals needed to repair damaged tissue.
Ultrasound energy also has the capacity to increase connective tissue permeability, providing another useful property in stretching, friction massage and muscle warm-up applications. In a similar manner, plastic objects when cold can be hard and inflexible; once warmed through ultrasound however, they become flexible and stretchable allowing more effective stretching or elongation.
Therapeutic ultrasound has long been utilized as an integral component of sports medicine, particularly for soft tissue injuries and tendonitis treatment. Studies have demonstrated its efficacy at reducing inflammation, increasing blood flow, improving collagen deposition during healing processes and increasing range of motion – among many other applications including helping remove scar tissue and cellulite. There are even applications such as tumor ablation using High Intensity Focused Ultrasound (HIFU), stimulating systemic drugs in capsule form or stimulating related nerve fibers; these applications fall outside the scope of this review but are well covered elsewhere by existing literature.
