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Extracorporeal Shock Wave Therapy |
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ESWT
Extracorporeal Shock Wave Therapy November 6, 2003
Andrea Wilson, PA
What is ESWT?
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Non-invasive acoustic wave released as pulsed energy.
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Use in orthopaedics was derived from lithotripsy for kidney stone
destruction.
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Germany first to study effects of shockwaves and it’s biological
effects in late 60’s, early 70’s. Designed lithotriptor machines. 1st
kidney stone procedure in ‘80.
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‘86 first experiments to determine effects on bones. Led to 1sr
orthopaedic device in ‘93 (Ossatron)
What is ESWT being
used for?
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Since early ‘80’s Europe has been using ESWT as an alternative to
surgery in the treatment of chronic soft-tissue problems including:
lateral epicondylitis, Achilles tendonopathy, rotator cuff calcifying
tendonopathy, plantar fasciitis and patellar tendonopathy.
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Some other areas of treatment and investigation include the
treatement of delayed union/non-unions and AVN of the femoral head.
How does ESWT work?
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An acoustic wave is generated and directed at the tissue to be
treated.
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Shockwaves travel through fluid and soft tissue, effects of the
energy produced are seen at a change in impedence. Each substance has a
different impedence. At the junction of changing impedence (I.e. at
soft tissue-bone interface) there is a build up of pressure and shear
loads.
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The result of the pressure change and shear loads results in
cavitation and cellular effects. The cellular effects include increased
cell permiability and stimulation of cytokine production which had been
found to induce neovascularization.
What does this mean?
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It is theorized that the mechanical changes induced by the
shockwaves result in:
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hyperstimulation analgesia, microdisruption of avascular or
minimally vascular tissue, to encourage revascularization and
recruitment of appropriate stem cells conductive to more normal tissue
healing.
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Benefits:
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Non-invasive procedure-avoid surgical risks and prolonged
recovery and time off from work.
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Patients are often able to return to work the next day or within
a few days.
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Few to no complications are reported.
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Minimal side effects
Indications
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Symptoms persist > 6 months
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Failed (at least three) of the following conservative treatments:
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Physical therapy, NSAIDS, appropriate orthotics/splinting,
activity modification, cortisone injection.
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Appropriate alternative diagnoses have been adequately ruled out.
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For example: Plantar fasciitis alternative dx-tarsal tunnel
syndrome, other metabolic arthropathies, SI neuropathy.
Adverse effects
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Mild/moderate pain during treatment
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Localized numbness/tingling
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Local subcutaneous hematoma, bruising, petechia
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Misdirection of focus may result in major nerve or blood vessel
damage.
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One study has reported one incidence of plantar fascia rupture in
treating plantar fasciitis*.
* Patient was documented to have had
a corticosteroid injection within 1 month prior to treatment with ESWT.
Contraindications
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OssaTron-according to the physician manual of recommended use has
no specific contraindications but has a warning concerning use in
patients with bleeding disorders or on anti-coag treatment.
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Current practice uses the following contraindications due to need
to continue investigation of effects in patient with the following
conditions:
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Patients with bleeding disorders, on anti-coagulation tx,
pregnant, have nerve damage, osteoporosis, rheumatoid arthritis, tarsal
tunnel syndrome, diabetic neuropathy, severe peripheral vascular
disease, metabolic disorders, or infection.
What does the
literature say?
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Biochemically/metabolic:
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C.J Wang et al: ‘02 in dogs, ‘03 in rabbits demonstrated
neovascularization and release of angiogenesis related markers in
treatment group was greater than control group at Achilles tendon-bone
junction. Concluded that neovascularization plays role to improve blood
supply and tissue regeneration.
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R. Wen-Wei Hsu et al: Also demonstrated effects of
neovascularization and demonstrated increased collagen synthesis and
collagen formation which when tested resulted in the new tendon tissue
demonstrating increased tensile strength and greater collagen
concentration.
Literature-biochem/metab con’t.
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F.S. Wang et al: Rat study demonstrated promotion of healing of
5mm segmental defect in bone in all specimens in treatment group
compared to control.
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Determined BMP-(bone morphogenic proteins) had a role in
signaling response in ESW treated rats.
What has been
demonstrated clinically:
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Plantar fasciitis:
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Ogden et al (F&A Int’l 4/02): Meta-analysis of published studies
determined 8 of 20 current publications fit criteria for adequate sound
studies. Of those studies success rates were as high as 88% of patients
having sufficient reduction in symptoms.
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Difficult to compare studies due to protocols varying greatly and
the machines used are not comparable in the amount of energy used.
Highlights of
Plantar Fasciitis studies:
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Ogden et al (June ‘01):
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322 patients randomized.
Treatment group received 1500 shocks (18kv). Total of 81% stated having
improvement in symptoms. (This study resulted in FDA approval for use
in treating PF with OssaTron)
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Rompe et al:
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several studies: 84 % success rate with 600 shocks, three
intervals, 88% success rate in different study where patients treated
with 1000 shocks in three weekly intervals. (Used Sonocur machine)
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Buch et al:
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Demonstrated in 110 patients at 1 year follow-up that 65% of
patients continued to have good or very good results. (This study
resulted in FDA approval for use in treating PF with Dornier Epos.)
Literature con’t.
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Chronic Calcifying rotator
cuff tendonitis
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C.J. Wang et al:
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31 shoulders treated (1000 shocks 0.18 mJ/mm) at 12 week
evaluation 23.8% had no complaints, 38.1% significant improvement, 14.3%
some improvement, 23.8% unchanged.
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Rompe et al: prospective
“quasi-randomized”
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29 surgery, 50 ESWT patients (3000 shocks 0.6 mJ/mm)
Concludedfor homogenous deposits before treatment surgery was superior,
vs inhomogenous deposits results were equivalent and would recommend
ESWT before surgery. (Sonocur)
Literature con’t.
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Speed et al:
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74 patients, double blind randomized controlled trial concluded
no added benefit in comparison to placebo for non-calcific tendonitis of
the rotator cuff. (1500 shocks at 0.12mJ/mm2, Sonocur)
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Lateral epicondylitis
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Crowther et al:
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Tested ESWT vs Cortisone injection: prospective randomized study
with 93 patients. Group 1 received one injection of 20 mg triamcinolone=84%
successful results. Group 2 received 2000 shocks in 3 weekly sessions
with 60% patients experiencing successful results.
Ending Remark
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There are numerous studies
published, of those out there, there is supporting evidence to suggest
good healing responses and reduction of symptoms in some patient
populations in the treatment of chronic tendonapathies.
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There are few head to head
studies showing that ESWT is superior to other conservative treatment
modalities, therefore it is not recommended as first line and is to be
considered “one other option” prior to surgical consideration.
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