For most patients who don't have fibromyalgia (FM), ultrasound can be an effective therapeutic modality for several soft tissue conditions. The conditions that respond well to ultrasound include dystrophy, taut bands, hypermyotonia, and active and latent trigger points. In our experience, the soft tissue condition most common and troublesome to FM patients is myofascial trigger points.

Myofascial trigger points in most FMS patients respond well to ultrasound. This is especially true when the ultrasound is used in combination with stripping massage, moist heat, and spinal adjusting.¹ As well as desensitizing trigger points and stopping pain referred from them, ultrasound has a pleasant, soothing effect on most FM patients.

The protocol for treating FM patients with ultrasound is basically the same as that for with patients who don't have FM . The main difference is that many FM patients have a lower tolerance for ultrasound intensity. With some FM patients, the intensity of the ultrasound must be reduced below the intensity that most other patients find comfortable. FM patients may have to be treated with very low ultrasound intensity, perhaps fewer than 0.1 watts/cm2. Similarly, muscle stripping usually has to be done very gently, with the amount of manual pressure properly adjusted according to constant feedback from the patient.⁴

Ultrasound is especially effective because of its multiple effects in soft tissues. No other modalities appears to have this set of tissue effects.³ The effects include the following. First, ultrasound energy is converted into heat at tissue surface boundaries due to waves meeting intra and intercellular resistance. This property is unique to ultrasound. The greatest effects of treatment occur where two unlike structures interface. Second, the fine vibrations from the ultrasound exert a micromassage effect on the treated tissues. Ultrasound can also alter the structure of scar tissue by breaking down the collagen fibrils with specific action on interstitial cement and by disengaging collagen cross bindings. Third, ultrasound has several chemical effects in tissues. For example, ultrasound stimulates streaming of calcium ions from cells, increases gaseous exchange and oxidation, and liquefies some cellular gels. Forth, ultrasound waves can induce the absorption of exudates and precipitates and can decrease edema. Fifth, ultrasound can inhibit impulse conduction in type C nerve fibers. Sixth, ultrasound waves may also cause microdestruction of tissue deposits such as calcified hematomas and osseous proliferations. Last, but very importantly, ultrasound waves may trigger enkephalin production, producing a mild sedative effect.²

Administering ultrasound in the continuous setting is preferable that in the pulsed setting. The effects of ultrasound listed above are induced only minimally by pulsed ultrasound. To get a therapeutic effect with pulsed ultrasound (except with edema) requires a prolonged treatment time.

The treatment protocol for myofascial trigger points includes positioning the patient comfortably so there is a slight passive stretch of the muscle to be treated. Some FM patients are uncomfortable maintaining the same body position for long during treatment. These patients should be permitted to reposition themselves whenever necessary so that they remain as comfortable as possible. However, the position the patient assumes should permit the muscle being treated to be relaxed, in a slight degree of stretch, and accessible to the ultrasound. The temperature of the room should be warm enough to prevent chilling of the tissue being treated.

During treatment with continuous ultrasound, the ultrasound transducer (head) should be moved continually to prevent excess heat from accumulation on the face of the ultrasound head and in the skin. However, the ultrasound head must be moved slowly during treatment, about 1.25-to-2.5 cm/second. The maximum depth of penetration of the sound waves is approximately 5 centimeters. When treating trigger points, the usual intensity setting is 1.0-to-1.5 watts/cm2. Contraindications are the same as for any other heat-producing modality.²

The size of the area to be treated is approximately 5 cm2 in diameter. ⁷ Attempting to treat too large an area will diminish the effectiveness of the treatment. Confining the ultrasound treatment to a small enough area allows the energy to be concentrated enough to reach the taut band and trigger point and have a strong therapeutic effect.⁶ The clinician should apply ultrasound to the trigger point for 4-to-5 minutes using a circular motion with the ultrasound head. The head should be moved at a speed of 1.25-to-2.5 cm/second. The intensity should always be adjusted to patient comfort. A warm, soothing effect for the patient is optimal.⁵ By the time the patient feels the soothing effect, the trigger point is usually desensitized. If the trigger point was referring pain before treatment, the referral has ceased. If the point was only locally painful, this too has usually ceased. However, the taut band will remain tender to pressure for a time. Feedback from the patient is essential for proper treatment. If the patient perceives excessive heat, the ultrasound intensity is too high and must be decreased.

Also, sound waves that are too intense for the individual patient can activate nociceptive mechanoreceptors in the taut band that houses the trigger point. This will cause pain referral from the trigger point. Again, the intensity should be decreased. Mild pressure may be applied with the sound head to obtain a muscle stripping effect. If the stripping action is painful to the patient, the clinician should decrease the amount of pressure or discontinue the stripping action.

Next, the clinician should apply moist heat for 5-to-8 minutes. The heat increases circulation by reducing sympathetic vasoconstrictive impulses to the taut muscle band that contains the trigger point. The heat also reduces alpha motor signals to the muscle, further decreasing the tone of muscle fibers around and in the trigger point region. After the use of heat, the clinician should passively stretch the muscle being treated. The stretching elongates the muscle fibers of the taut band, disengaging the actin and myosin fibers, and permitting normal circulation to resume.⁷

Finally, the patient's spine should be gently adjusted. Any force applied during the adjustment should be calibrated to the FM patient's lower tolerance. Adjusting fixated spinal joints usually relaxes the patient and provides a sense of well being. However, adjusting spinal joints that are segmentally related to the muscle containing the trigger point can be especially effective. Adjusting segmentally-related spinal joints reduces motor activity in the involved muscle and decreases its sympathetic innervation.⁸

The patient should be instructed in home care consisting of the use of moist heat and gentle stretching of the involved muscles. For some patients, home treatment is more effective after the intake of a mild analgesic.⁷