By Michelle Apuzzio, MSPT
Rehabilitation professionals cannot seem to reach a consensus about ultrasound. Some therapists consider it an integral part of most treatments. Others keep their machines stuffed in closets, collecting dust, because they do not know how to effectively use the modality.
Many myths surround the use of ultrasound. Michelle Cameron, MD, PT, OCS, has found that therapists are all over the board in terms of their perceptions. Some of the more popular, yet false, beliefs about the modality are that it pushes drugs through the skin, that it does not do anything at all, and that it should never be used over fractures or metal.
Cameron conducted research primarily on phonophoresis, the topical application of anti-inflammatory medication via ultrasound, in the early 1990s to examine whether medications allowed ultrasound to pass through them. Most didn't, including the widely used hydrocortisone cream. "Some people still use hydrocortisone cream, ignoring the fact that ultrasound doesn't go through it very well," she says.
As for the contraindication in fractures, last April the Centers for Medicare and Medicaid Services (CMS) approved ultrasound's use for nonunion fractures prior to surgical intervention. Previously, coverage was limited to those who had failed at least one surgical intervention. The decision memo indicated that the scientific literature attributed the following physiological effects to ultrasound used on nonunion fractures: increases in signaling pathways in osteoblasts, release of growth factors, enzymatic activity, calcium absorption, blood flow to the fracture site, and callus formation.
The fact that research exists to support ultrasound's abilities is a strong step toward convincing skeptical therapists that the modality has its merits. It may be tricky to find that data, however. Sara Shapiro, MPH, PT, an assistant clinical faculty member at the University of California at San Francisco, does a literature search on ultrasound before each of the continuing-education classes she teaches on the subject. The research is there, she says, but it is not always in the physical and occupational therapy publications. She often plucks articles from the biochemistry, biology, and biophysiology journals to find the latest information on ultrasound.
DIGGING DEEPER But therapists must often dig deeper than researchers' conclusions, looking for inherent study flaws, before applying the findings to practice. One article that ran in the American Physical Therapy Association's national journal drew much rebuttal from ultrasound proponents. In the study, which was conducted in Turkey, researchers concluded that ultrasound was not effective for treating shoulder injuries.
But Shapiro notes that the investigators performed ultrasound using the same duration and level of heat on all shoulders involved. While the researchers may have thought they were being consistent for the sake of the study, the design mimics an issue that Shapiro and Cameron see with some clinicians who use the same machine settings regardless of what they are trying to achieve. "In order to get the best results possible with this modality, as with any other, it does really need to be applied in a specific, guided way," says Cameron. "I think it's often discarded as being ineffective because people use the same setting for every single problem and then find it doesn't work."
Clinicians can manipulate the size of the area treated, and the frequency, duty cycle, intensity, and duration of treatment. "And every one of them matters," says Cameron. Although many therapists know they can change the settings, Cameron finds many in her continuing-education courses who do not understand the difference it would make. Frequency, she says, affects the depth of penetration; 1-MHz ultrasound penetrates deeper than 3-MHz ultrasound. Intensity settings are based on that factor, in addition to whether the therapist is using a continuous or pulsed setting.
With the machine on a duty cycle of 100%, or continuous ultrasound, the therapist can achieve deep heating of the tissues. On the pulsed setting, most commonly a 20% duty cycle, the ultrasound will provide mechanical agitation. Although ultrasound machines often allow the therapist to set various duty-cycle percentages, Cameron says that most of the data on pulsed ultrasound focus on a 20% duty cycle.
Lastly, clinicians must take into account the size of the affected area and the duration of treatment. The effective radiating area (ERA) is different for each sound head, but in her book on physical agents, Cameron states that an area twice the size of the sound head can be effectively treated in 5 to 10 minutes.
VICTIM OF NEGLECT Although it could be that some schools are providing only a cursory introduction to ultrasound, Cameron thinks part of the problem is the way therapists are encouraged to document it, especially if the note merely includes a place to "check off" whether ultrasound was performed. Instead, she argues that therapists should document it as carefully as they would exercises that the patient performs.
The actual equipment can be another issue. When Shapiro taught a continuing-education course in Baltimore, the California resident did not bring any new ultrasound machines with her. Instead, she asked the small class to bring their own equipment. All five machines were more than 35 years old and had only a 1-MHz sound head. Three of them did not work at all. "Then you ask why ultrasound doesn't work, and I'll ask you, ‘Can you drive a 1928 Ford if no one takes care of it?'" she asks.
Besides keeping equipment in good condition and making sure settings are appropriate for therapeutic goals, the other pressing issue for therapists is whether to use ultrasound at all with a particular patient. "I see ultrasound as being guided by impairment rather than by diagnosis," says Cameron.
In general, therapists may include it in a treatment program to address soft tissue inflammation, muscle spasms and trigger points, calcium deposits, and pain management. When making the decision to use ultrasound, Stephanie Leslie, MSPT, a physical therapist in the outpatient department at St Joseph Hospital in Nashua, NH, takes into account the amount and consistency of the pain and the size of the affected area. If the patient has consistent, localized pain or significant loss of function, Leslie uses ultrasound to address those issues.
In Leslie's experience, she has seen good results with ultrasound used on patients with tendinitis, bursitis, adhesive capsulitis, contusions, and trigger points and strains in the cervical and mid-scapula areas. She stresses that ultrasound is an adjunct modality to patient education, body-mechanics training, range-of-motion exercises, and strengthening. "Ultrasound is a great modality for treating symptoms of a condition, but it will not reverse or help alleviate the condition or original cause by itself," she says.
At times, that can be a difficult concept for patients to grasp. In her seminars, Shapiro hears about therapists who have trouble weaning patients from ultrasound. In her practice, she prepares patients to feel worse initially after having an ultrasound treatment, especially one at a continuous setting. She asks them to report when they started feeling better and how long it lasted. If they are unable to provide that feedback, she is likely to discontinue ultrasound treatment.
The patient's attitude also can affect how well ultrasound works. Paul Tobio, PTA, a physical therapy assistant at Harvard Vanguard Medical Associates in Boston, sees the best results with patients who are compliant with all aspects of their plan of care, including exercises and self-management of symptoms.
Patients who come in seeking ultrasound raise a red flag for many therapists, including Leslie and Tobio. Leslie avoids using ultrasound in patients with chronic pain because the treatments can be performed only a limited number of times. In addition, she prefers to focus on modalities these patients can use at home, such as ice, heat, and TENS, although plenty of patients jokingly ask if they can take ultrasound units home with them.
Convincing patients when to let go of ultrasound can be as challenging as teaching veteran therapists how to effectively incorporate ultrasound into treatment. Leslie admits that she uses it much more than when she began practicing 5 years ago as a new graduate.
For Shapiro, that is one of the most rewarding parts of her seminars. "People will come up afterward and say, ‘You know, we're not doing ultrasound right in our clinic, which is probably why we're getting such terrible results,'" she says. "And I look at them and say, ‘If you could hold that piece of information and actually take it back to your clinics and get other people to look at that, this will have been a really worthwhile seminar.'"
Michelle Apuzzio, MSPT, is a contributing writer for Rehab Management.
RESOURCES Cameron, MH. Physical Agents in Rehabilitation: From Research to Practice. 2nd ed. St Louis: WB Saunders; 2003.
Centers for Medicare and Medicaid Services, Medicare Coverage Database. Available at: http://www.cms.hhs.gov/mcd/viewdecisionmemo.asp?id=135. Accessed May 16, 2005.
Kurtais GY, Ulus Y, Bilgie A, Dincer G, van der Heijden GJ. Adding ultrasound in the management of soft tissue disorders of the shoulder: a randomized placebo-controlled trial.Phys Ther. 2004;84:336-43.
