Download Shock wave therapy offers alternative to surgery

BioMechanics
June 2001
Pain Management
Shock wave therapy offers alternative to surgery
By Kate Madden Yee
Sidebar: White Sox go to bat for ESWT
Of the roughly two million cases of heel pain reported in the U.S. each year, most respond well to
conservative treatments such as rest, shoe modification, anti-inflammatory medications, custom or overthe-counter orthotic devices, and physical therapy. For the 10% to 20% of people who don’t find relief
through these options, however, surgery can begin to seem inevitable. Yet surgery doesn’t promise
complete relief, and can even create more problems, adding long recovery times and the risk of
complications to a patient’s list of worries.
“Heel pain can be treated conservatively most of the time,” said Lowell Scott Weil Jr., DPM, of the Weil
Foot and Ankle Institute in Des Plaines, IL. “But some people don’t get better, and there’s no rhyme or
reason why. That’s when surgery becomes an option.”
But a treatment called extracorporeal shock wave therapy is emerging as a noninvasive, outpatient
alternative to surgery that allows some patients to get back on their feet within days or weeks, rather than
months. Some practitioners believe ESWT’s success rate is equal to that of surgery, without the exposure
to complications.
ESWT sends pulses of acoustic waves into bone or soft tissue, in effect reinjuring the area on a cellular
level and breaking up scarring that has penetrated tendons and ligaments. The controlled reinjuring of
tissue allows the body to regenerate blood vessels and bone cells. Depending on its energy level, ESWT
procedure takes between 15 and 45 minutes as the device delivers 1500 to 4000 acoustic pulses at a rate
of approximately two per second. ESWT advocates believe the therapy is effective in reducing chronic
musculoskeletal pain for at least three reasons: The shock waves stimulate a metabolic reaction in the
affected tissue, causing stress fibers to develop and/or change in their permeability; they generate
cavitation bubbles that break down calcific deposits; and they induce an analgesic effect by stimulating the
brain’s gate-control mechanism, which blocks pain messages. In many cases, patients feel no pain after a
treatment, and are able to resume normal physical activities within days.
The therapy is related to lithotripsy, a technology developed in Europe in the 1980s for treatment of
kidney stones. Researchers found that lithotripsy initiated a natural healing process to break up the
stones, and began to explore the use of a similar technology for orthopedic problems. In the U.S.,
although lithotripsy is commonly used to treat kidney stones, the only orthopedic application for ESWT
approved by the Food and Drug Administration is plantar fasciitis, although clinical trials for other
applications are being conducted. Since the procedure was developed, it has been used outside the U.S. to
treat such conditions as tennis elbow; nonunion fractures; avascular necrosis of bone; and shoulder,
patellar, and Achilles tendinitis.
Many companies in the U.S. and Europe are developing ESWT devices of varying technology and energy
levels, including Dornier Medical Systems, Norland Medical Systems, OrthoWave, Siemens, and Storz. In
the U.S., only HealthTronics’ OssaTron Orthotripter has received marketing clearance from the FDA,
according to the agency. OssaTron was cleared in October for performing ESWT in patients with chronic
proximal plantar fasciitis that hasn’t responded to conservative treatment.
Norland’s Orbasone, which some practitioners use for ESWT, was initially designated as a therapeutic
massage class I device by the FDA. In October, the FDA sent Norland a letter warning letter that the
company had been marketing Orbasone for applications not covered by the class I designation, specifically
treatment of soft tissue pain. The agency demanded that the company pursue appropriate clearance for
use of the device for ESWT. Norland was unavailable for comment on Orbasone’s FDA status.
“We received a submission (from Norland) that asked for our determination whether Orbasone was a
therapeutic massager, and initially we agreed,” said Wally Pellerite, assistant to the director of the FDA’s
Office of Compliance. “But on closer scrutiny, it was determined that it was not a therapeutic massager,
but a shock wave device. Norland has indicated that they stopped distribution of those devices, and that
they will proceed with obtaining other clearances that are necessary.”
Three Technologies
Three main types of extracorporeal shock wave technology are currently in use around the world:
electrohydraulic, electromagnetic, and piezoelectric. Electrohydraulic technology is associated with highenergy ESWT, and is the only type cleared in the U.S. Electrohydraulic devices fire spark plugs inside a
water-filled bellows that is placed against the patient’s body. Energy generated by the spark plugs hits a
metal ellipsoid, which focuses the waves toward the far end of the bellows, through which they are
emitted into the area being treated. OssaTron, Orbasone, and OrthoWave all employ this technology.
Electromagnetic and piezoelectric machines are associated with low-energy ESWT, which means they can
be used without anesthesia, although practitioners can choose to use low-energy machines at higher
energy levels. Electromagnetic devices use loudspeaker-like coils to create the pressure wave, while
piezoelectric units use crystals to create the wave. Examples of electromagnetic ESWT devices are
Siemens’ Sonocur and Dornier’s EPOS Ultra; an example of piezoelectric technology is German company
Richard Wolf’s Piezoson 300.
Companies measure ESWT device energy levels differently: Some use megaPascals (mPa), others use
kiloVolts (kV). Norland’s Orbasone has an energy level range of 64 mPA to 89 mPA; HealthTronics’
OssaTron has a range of 18 kV to 26 kV. This energy range can be manipulated by practitioners,
depending on their clinical judgment regarding the condition being treated and the type of device they’re
using. A plantar fasciitis treatment might be conducted at the lower end of the range, while a treatment
for a nonunion fracture might be conducted at the higher end.
When a patient undergoes high-energy extracorporeal shock wave therapy for plantar fasciitis, he or she is
either put under intravenous sedation or the painful area is anesthetized locally. The ESWT unit head,
which contains the spark plug, the electromagnetic coil, or the piezoelectric crystals, is placed against the
patient’s heel. The practitioner focuses the head in a particular area of the pathology, using an energy
level he or she has determined is appropriate to the pathology. Some companies that have developed lowenergy ESWT devices use ultrasound to help practitioners determine where to direct the shock wave, while
companies with high-energy devices, which tend to have larger focal areas, do not, and doctors palpate
the patient’s foot themselves.
Practitioners and device manufacturers disagree on the question of whether high- or low-energy ESWT is
better for patients. High-energy advocates believe that the procedure is more effective with higher
pressure, and emphasize the fact that the therapy is usually accomplished in a single treatment, which is
attractive to patients. According to low-energy ESWT advocates, these treatments are less expensive than
a single procedure with a high-energy device, do not cause as much post-treatment pain and swelling as
high-energy treatments may, and do not require anesthesia. Companies like HealthTronics and Norland
have chosen to focus on developing high-energy electrohydraulic units, while companies like Dornier have
chosen low-energy electromagnetic devices.
Siemens has been developing its low-energy ESWT device, Sonocur, for use treating tennis elbow. Clinical
trials for Sonocur began in early 1999 at Peachtree Orthopedic Clinic in Atlanta, Miller Orthopedic Clinic in
Charlotte, NC, and Commonwealth Orthopedic and Rehabilitation Clinic in Arlington, VA. The trial includes
114 participants among the three sites. Sonocur is currently marketed in Europe and Canada for the
treatment of other chronic pain disorders. Similar in size to an ultrasound unit, Sonocur has a suspension
arm that transmits the shock waves. The waves are generated through a coupling bellow and the shock
wave source, which emits four acoustic pulses per second. Since Sonocur is used at the lower end of the
energy spectrum, patients do not require anesthesia, although they undergo three procedures in three
weeks for their treatment.
Effective Treatment
Whether a physician uses a high- or low-energy ESWT device, clinical trials seem to support ESWT’s
effectiveness. HealthTronics’ studies for OssaTron included 350 people who had had symptoms of
moderate to severe pain in the affected heel for at least six months prior to study enrollment and whose
condition had failed to respond to at least three attempts at treating the pain with conservative options.
Subjects were followed at four weeks, eight weeks, and 12 weeks post-treatment, and an initial
success/fail status was assigned based on findings at the 12-week mark. Of the total study cohort, 130
people were assigned to the active treatment group.
The study found that at the 12-week postprocedure mark, investigator assessment pain scores of active
ESWT treatment participants improved from a mean baseline Visual Analog Scale score of 7.68 to 3.13 at
12 weeks, while the median 12-week VAS score was 1.9. Active participants’ self-assessment pain scores
improved from a mean baseline VAS score of 8.02 to 3.48 at 12 weeks, and the median 12-week VAS
score was 2.6.
According to clinical data collected by the Weil Foot and Ankle Institute, which has performed more than
130 ESWT procedures since February 2000, up to 82% of the institute’s patients experience a reduction in
pain scores of at least five points on a scale of zero to 10, with 10 being the most severe pain.
“Almost all patients find noticeable improvement of previous pain in two to three days,” Weil said.
“Although it can take two to three months to appreciate the full benefits of the therapy.”
Despite the large number of chronic musculoskeletal pain sufferers around the world, extracorporeal shock
wave therapy’s biggest barrier is the fact that it is still under investigation in the U.S. for applications
besides plantar fasciitis, and that the procedure is not covered by most insurance policies. This means
patients often pay out-of-pocket for the technology, and a high-energy procedure can cost between $4000
and $5000. ESWT devices can cost $200,000 to $500,000, although not all companies actually sell their
units: HealthTronics installs OssaTron at clinical sites and bills third-party payers-whether insurance
companies or patients-so physicians don’t buy the device themselves. HealthTronics has about 25
OssaTron units installed across the U.S.
As the therapy’s clinical effectiveness continues to be proven, practitioners expect patients to request
ESWT sooner rather than later, making the treatment a solid alternative to surgery, according to Weil.
“ESWT isn’t a cure-all,” Weil said. “But it can be an effective tool. Perhaps in the future, it will be used
earlier in treatment protocols because it’s noninvasive and it has a low complication rate.”
Kate Madden Yee is a freelance writer based in San Francisco.
Sidebar
White Sox go to bat for ESWT
ESWT’s quick recovery time can get professional athletes back in their game more quickly than if they
undergo surgery. Lowell Scott Weil Jr., DPM, is the team podiatrist for the Chicago White Sox and has
used ESWT on players. Last year, he performed the treatment on designated hitter Frank Thomas, who
had injured his posterior tibial tendon in the first week of the season.
“He had the ESWT procedure on a Sunday night, and hit a home run the following Tuesday,” Weil said.
The treatment relieved the pain Thomas had been feeling, according to team trainer Herman Schneider,
ATC, who had a low-energy ESWT device installed at Comiskey Park.
“He was playing anyway, but the treatment made the discomfort subside much more quickly,” he said.
“We’ve used it quite a bit, for (any injury) that has had chronic inflammation brewing. Hamstrings, backs,
knees, ankles. Stuff that lingers, that you can’t seem to get rid of.”
Schneider said players have become accustomed to the procedure, especially since it can mean the
difference between playing and not playing during the season.
“Initially the guys were shocked because the machine’s very loud, but after a while, they got used to it,”
Schneider said. “One guy fell asleep during the treatment. He eventually needed surgery anyway, but
(ESWT) kept him going through the end of the season.”
Frank Thomas, designated hitter for the Chicago White Sox.
© 2001 CMP Media, LLC
6/1/01, Issue # 806, page 75.
© 2001 CMP Media, LLC, a United Business Media company