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What Studies Say About Shockwave Therapy
By David Zuckerman, DPM
November Issue, 2002
article from Podiatry
Today
As
podiatric physicians and surgeons, we would like to treat chronic
plantar fasciitis without the risks and complications that are inherent
to common plantar fascia releases. We have studied lower extremity
biomechanics and have been taught that with all surgical procedures,
we must understand and respect the function of the human foot and
how each surgical procedure changes its specific function and stability.
However,
studies of extracorporeal shockwave therapy (ESWT) have proven that
we can cure chronic, insertional plantar fasciitis without exposing
patients to any of the known risks (ranging from infection and nerve
entrapment to reflex sympathetic dystrophy (RSD) and calcaneal-cuboid
syndrome) associated with any type of surgical plantar fascia release.
How
Do Shockwaves Work?
So how does this noninvasive treatment work? Well, there is nothing
mystical or cryptic about a shockwave. It is nothing more than a
sonic boom. A shockwave is produced by electromagnets generating
a signal through water. The signal is directed through a lens to
direct all of the energy to a single focal point. Using an ESWT
device enables you to place the patient’s foot on that focal
point, where it receives all the directed energy to the damaged
tissue.
A shockwave has certain physical characteristics. There is a high
peak pressure (sometimes more than 100 Mpa), but the average pressure
of shockwaves is approximately 50 Mpa with a short lifecycle of
approximately 10 ns. In addition, there is, by definition, a fast
initial rise in pressure of less than 10 ns and a broad frequency
spectrum that is typically in the range of 16-20 Hz.
When
a shockwave enters tissue, it may break up and reflect the absorption
of kinetic energy by the precise body structures (bone, fat, tendon,
ligaments), which are exposed to the shockwave.(1) All techniques
of shockwave production (electrohydraulic, electromagnetic and piezoelectric)
depend on the conversion of electrical energy to mechanical energy.(1)
When
a sound wave is transmitted into tissue, there are two levels of
transmission: low energy and high energy. Low energy has an analgesic
effect by either disrupting the cell membranes partially or completely.
When high energy (any energy greater then 0.28mJ/mm2) comes in contact
with the damaged tissue, there is a direct biological interaction.
The body will react by increasing blood flow to the area, initiating
vascular neogenesis and a reparative cycle. When you apply high
energy to the insertion of a damaged plantar fascia, the reparative
healing begins. This process leads to fibroblastic production and
new healthy tissue in the area that was once avascular tissue.
What
The Early Studies Revealed
So what do the studies reveal about the effectiveness of this technology?
Scientists began testing shockwaves on animals to determine the
effects on wound healing. They were able to show that low energy
shockwaves stimulated wound healing and high energy shockwaves prolonged
wound healing.(2) Another study tested the effect of shockwaves
on non-union fractures. The results showed that shockwaves stimulated
osteoblastic activity in pseudarthrosis and could be used to heal
fractured bones.(2)
Dahmen, et. al., first used shockwaves to treat soft tissue pain
in proximity to bone. They administered a total of 4,892 shockwave
sessions to 512 patients.2 More than 30 different syndromes were
treated with 52 percent of the patients having good results, 28
percent improved and only 3 percent requiring surgery. Dahmen's
work was the beginning for ESWT for tendopathies.
Ching-Jen Wang, et. al., investigated the effectiveness of shockwaves
on painful heel spurs. The prospective clinical trial involved 66
patients, including 45 males and 21 female patients with an average
age of 47.7 years.(3)
Each
treatment with the OssaTron device (Healthtronics) consisted of
1,000 impulses of shockwaves with a 14 kv generator voltage. Twelve
patients received a second treatment and two received three treatments
each. All of the patients in this study had the standards for pre-ESWT
applied: pain for at least six months, failure to improve with at
least three conservative treatments (i.e. steroid injection, NSAIDs,
orthosis and physical therapy). Exclusion criteria included patients
with severe PVD, patients under the age of 18, those who had cardiac
pacemakers, those with systemic/local infection and those who were
pregnant.(3)
(Please
note that when talking about treatments, in order to compare treatment
protocols, you need to provide the energy applied in mJ/mm2 at the
focal site of the specific ESWT device you use. The study by Ching-Jen
Wang, et. al., used the OssaTron, but didn’t specify the amount
of energy that was used. However, at this time, the study remains
a very important study supporting ESWT effectiveness.)
The
clinical results in this study were very encouraging. At the week
12 evaluations, 80.4 percent of the patients noted complete or nearly
complete resolution of symptoms, and 17.1 percent noted partial
improvement.(3)
In my opinion, this study reached two very important conclusions.
The first conclusion is that shockwave treatment for a painful heel
spur may improve from week six to week 12. This study showed additional
shockwave sessions improved the patients’ heel spur symptoms
when the first treatment failed to show improvement.
Getting
A Handle On Studies That Offered Follow-Up Results
One of the first studies to offer one-year evaluations revealed
very positive results in using high-energy shockwave treatments
to treat painful calcaneal spurs.(4) If you include both "pain-free"
and "improved" patients with this high-energy treatment,
the study depicts 85 percent patient satisfaction one year out from
treatment.
These
researchers do not mention the type of ESWT equipment they used
but their treatment protocol is very similar to the treatment protocol
Dornier MedTech submitted to the FDA for its clinical trial.(4)
This article notes the amount of shockwave pulses (3,000 impluses
for 83 patients) and the high energy levels (.30 mJ/mm2.) This type
of reporting makes it possible for any ESWT practitioner to compare
any treatment protocol to that of his or her own.
A
group led by Lowell Scott Weil Sr., DPM, and Lowell Scott Weil Jr.,
DPM, recently treated 40 feet with high energy ESWT.(5) The average
kv used was 20.6 with an average of 2,506 pulses delivered to the
foot. All patients treated were under IV sedation and received a
post-EWST local steroid injection. The mean follow-up time was 8.4
months.
Results
of the study showed that 82 percent of the patients were satisfied
with treatment results. Researchers noted no long-term serious complications.(5)
Beginning in January 1999, I used the Orbasone Machine to treat
100 patients, using the standard treatment protocol as outlined
by the manufacturer.(6, 7) This consisted of 16 kv (0.6mJ/mm2),
applying 3,000 pulses to the insertional plantar fascia medial attachment.
All patient treatments were either administered with local anesthesia
or an administration of low energy to prepare for high-energy treatment.
A one-year follow up revealed that 83 percent of patients reported
satisfaction with this treatment protocol. I concluded ESWT was
very effective for treating chronic heel pain associated with proximal,
insertional plantar fasciitis.(6)
What
About The FDA Study On The Epos Ultra?
Earlier this year, Dornier MedTech garnered FDA approval for its
Epos Ultra device, which has already been in use for many years
in Europe and Canada. The FDA clinical trial was a multi-center,
double-blind, randomized study consisting of 150 patients.(7) Seventy-five
patients received treatment and 75 received a placebo treatment.
As
far as the criteria for inclusion in the study went, each of the
150 patients must have had plantar fasciitis for two years. Three
failed conservative treatments were the minimum. Also, it should
be noted that patients who had autoimmune diseases, diabetes, peripheral
vascular disease or had had previous heel spur surgery were excluded
from the study.(7)
The treatment protocol consisted of 3,800 shocks of high energy,
0.36mJ/mm2, at 240 pulses per minute. In order to make sure the
energy was directed at the insertion site, researchers used inline
ultrasound guidance. They administered shockwaves under direct visualization
at all times. They also used local anesthetic to ensure patients
could tolerate the procedure, and at no time needed to employ general
or IV sedation.(7)
Patients were examined at three days, six weeks, 12 weeks, six months
and one year. The FDA reporting was up to 12 weeks, which is standard.
However, a continuation of the study was followed up to one year
by the treatment centers involved in the study. Researchers used
visual analog scale (VAS) scores (0-10 with 10 being the highest
degree of pain) and the Roles & Maudsley Pain Evaluation to
determine the efficiency of ESWT at the different timeframes.(7)
An average pre-ESWT VAS was 7.7 for the baseline FDA study. Three
to five days after treatment, the VAS score was 5. Week six showed
average scoring of 4.6. Week 12 showed a 3.4 score and revealed
that over 60 percent of the patients experienced a good to excellent
result. In six months, VAS scores dropped to 2.2 and finally dropped
to a low of 0.6 at the one-year mark. This was a 92 percent reduction
in pain from the initial pre-ESWT score of 7.7.(7)
The Roles and Maudsley scoring was impressive. Ninety-four percent
of the patients treated with the Epos Ultra scored either a 1 or
a 2 out of four scoring grid. The following is the definition of
each level for scoring recorded:
- Excellent:
no pain, no restriction for movement and activity
-
Good: occasional pain, no restriction for movement and activity
-
Fair: with pain during rest and exertion or loading
-
Poor: daily activities limited by pain
(It should be noted that at 12 weeks, 56 out of the 75 people
who received a placebo treatment were offered the opportunity
to to cross over into the study to receive the ESWT.)
In
Conclusion
The FDA studies indicate, as do other studies and my own three-year
involvement with ESWT, that shockwave therapy is very effective
and safe for chronic, proximal, insertional plantar fasciitis with
or without heel spurs.
The results are excellent with no long-term complications. ESWT
has none of the problems or serious complications that result from
any type of fascial release with or without heel spur resection.
These patients don’t have to worry about the increased risks
of infection, nerve entrapment, RSD, fracture and additional biomechanically
induced pain due to the main support system of the human foot being
cut.
As
podiatric foot and ankle specialists, we are at the frontier of
this amazing technology. We can now treat the over 250,000 cases
of insertional plantar fasciitis that won’t respond to other
treatments. I hope more podiatrists reach out and understand just
how beneficial ESWT is to their patients and to their practice.
Many
podiatrists won’t offer ESWT to their patients due to the
economic cost of the procedure. However, I believe that as time
passes, more and more insurance companies will take a look at this
marvelous procedure. Don’t let non-insurance coverage stop
you from providing a non-invasive procedure to your patients. Patients
need to know about all of the treatment options, especially the
non-invasive ones, before considering surgical therapy.
Dr.
Zuckerman is the Podiatric Medical Director for Excellence Shockwave
Therapy Group, a group of over 45 podiatric physicians and surgeons
who provide ESWT in outpatient settings. A Fellow of the American
College of Foot And Ankle Surgery, Dr. Zuckerman practices in Woodbury,
NJ.
References
(1) Musculoskeletal Shockwave Therapy, Coombs, Schaden, Zhou, Greenwich
Medical Media, Ltd. 2000.
(2)
Use of Extracorporeal Shockwave in the Treatment of Pseudoarthrosis,
Tendinopathy and Other Orthopedic Diseases, Gerald Haupt, Journal
of Urology Vol 158, July 1997.
(3)
Use of Extracorporeal Shockwave in the Treatment of Pseudoarthrosis,
Tendinopathy and Other Orthopedic Diseases, Gerald Haupt, Chapter
12, Heel Spurs, author Ching-Jen Wang, Journal of Urology Vol 158,
July 1997.
(4)
Perlick L, Boxberg W, Giebel G. “Hochenergetische Stosswellenbehandlung
des schmerzhaften Fersensporns,” Unfallchirurg 1998 Dec;101(12):914-8
22. (This article is written in German.)
(5)
Weil, Jr., LS, Roukis, TS, Weil, Sr., LS, Borrelli, TS. “Extracorporeal
Shockwave Therapy for the Treatment of Chronic Plantar Fasciitis:
Indications, Protocol, Intermediate Results, and a Comparison of
Results to Fasciotomy,” Journal Of Foot And Ankle Surgery
41(3):166-172, 2002.
(6)
Zuckerman, D. Personal surveys published on web site heelspurs.com.
(7)
Dornier MedTech Physician Training Manual.1999 US Distributor. 1155
Roberts Blvd. Kennesaw, GA."
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