Recently, I read a research report by Hong, Chen, Pon, and Yu.[l] They reported the results of their study of the effects of four therapeutic modalities commonly used by physical therapists and other practitioners who treat myofascial trigger points. The modalities they tested included stretch and spray, moist heat, ultrasound, and deep pressure soft tissue massage. The results are somewhat problematic for me because they are highly inconsistent with my clinical experiences.

These investigators compared the relative effectiveness of the four modalities. It is the outcome of this comparison that I was puzzled over. The investigators wrote that all four modalities were effective in the treatment of myofascial pain syndromes. They induced an immediate increase of pain threshold of active myofascial trigger points. They reported that deep pressure massage therapy was more effective than the other modalities in reducing the tenderness of active trigger points immediately after therapy. They also reported, "The stretch therapies [including spray and stretch and deep pressure massage] are more effective than thermotherapy [hydrocollator and ultrasound] in obtaining an immediate increase in pain threshold for myofascial pain treatment."[1,p.50]

I’ve treated patients’ trigger points for over 10 years, and I’ve used extensively each of the four modalities tested in the Hong, et al. study. For some five years, I wasn’t certain whether one modality worked better than the others. I worked diligently to master the use of each, and neither seemed to consistently work better than another.

In 1990, however, I attended a workshop taught by Dr. John C. Lowe.[2] That weekend, Dr. Lowe demonstrated the use of ultrasound to treat trigger points. According to the principles of ultrasound treatment he taught, my results with ultrasound were relatively ineffective for several reasons. I’d: (1) used pulsed rather than continuous mode, (2) moved the transducer at too fast a rate over the trigger point, and (3) failed to place the patient so that the muscle containing the trigger point was stretched somewhat during the ultrasound application.

At the workshop, I had some doubts about the wisdom of his advice. But when I used it back at my office, I found that what he had confidently asserted—that in 99% of cases, when applied properly, continuous ultrasound can stop an active trigger point from referring within 4.5 minutes—was precisely correct. My results dramatically improved, and as I’ve continued to refine my ultrasound technique, I've come to agree completely with Dr. Lowe: that continuous ultrasound is the most potent procedure available for stopping pain and other symptoms mediated by trigger points.

Of course, ultrasound is not a sole treatment for trigger points. I stretch the muscle as I apply ultrasound. After the ultrasound, I apply some soft tissue manipulation (a combination of ischemic compression and stripping massage). Next I apply moist heat, and then I have the patient actively stretch the muscle. Certainly these additional therapeutic procedures contribute to the treatment outcome, but without the ultrasound application, the sequence of other procedures is far less effective. I know this because the detailed progress notes I’ve kept on patients over the years I’ve treated for trigger points has allowed me to compare the results of the different protocols I’ve used. It is these learning experiences that make the results of Hong, et al. a little off base to me. When I read the study, I was actually startled at the results. I carefully read the paper, especially the parts describing how ultrasound was applied. The study was well done, and my assumption was that ultrasound must have been applied correctly. When I closely considered the technique used in the study, the conclusion I came to was that deep soft tissue massage seemed to be more effective because the ultrasound transducer (head) was moved too rapidly. The investigators pointed out that the ultrasound head was moved 3 to 5 cm (1.18 to 1.97 inches) per second.

I'll contrast Lowe’s technique with that used in the Hong et al. study. This will serve to emphasize the critical differences—and similarities—in technique. Hong and colleagues wrote: "The ultrasound deep heat therapy was applied to the upper trapezius area of approximately 40-50 cm2 with the [trigger point] at the central portion. The ultrasound dosage was set at 1.2-1.5 watt/cm² for 5 minutes, as is usually recommended for soft tissue therapy to a small body part. The speed of the circular movement of the ultrasound applicator was constant and slow, at a rate of approximately 3-5 cm per second evenly applied on the treatment area, so that the patient always felt warm during therapy."[1,p.44]

When I studied the report of Hong et al., I found several consistencies with the technique I’ve found highly effective. First, the dosage of ultrasound is within the range I’ve typically found effective, 1.2 to 1.5 watts/cm². In addition, five minutes wasn’t far off the average of four and one half minutes Dr. Lowe has reported.[3] But the tissue area included in the five minute treatment (40 to 50 cm2 or 15.75 to 19.69 inches squared) is far too wide to be highly effective. One change I made in my ultrasound technique at Dr. Lowe’s recommendation was to concentrate the ultrasound application to roughly the 2 square inch area of skin overlying the trigger point. This allows maximum concentration of the ultrasound energy into the taut band containing the trigger point. Cover a wider area, and too little ultrasound energy may reach the taut band and trigger point to have a strong therapeutic effect. This particular difference may be the critical ingredient in the significant result I've found.

Other differences advocated by Lowe are: slight stretch of muscle being treated, deep pressure applied through the sound head, and maximum heat permitted through slow movement of the sound head. Dr. Lowe states that he arrived at his method through meticulous record keeping as to how patients responded to various ultrasound applications. He quotes Jaskoviak and Schafer[4,p.209] as stating, ". . . dosage levels, while limited, are made strictly on an empirical basis." In line with his, Dr. Lowe states[5] that his technique isn’t based on unblinded studies, but on a sincere effort, with the benefit of algometry, to assess the trigger point desensitizing effects of various modalities.

I would like very much to see a controlled examination of the effects of continuous ultrasound used according to the method taught by Dr. Lowe. My prediction is that ultrasound should have a better showing than it did in the Hong et al. study.

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