Extracorporeal shock wave therapy (ESWT) is a non-invasive treatment that
involves delivery of an acoustic shock wave to a specific area of the body.
The objective of this treatment is to reduce pain and stimulate healing of the
affected area. The acoustic waves travel through fluid and soft tissue, and
their effects occur at sites where there is a change in impedance, such as the
bone/soft-tissue interface.

ESWT has become a proposed treatment option for specific musculoskeletal
conditions. These conditions include, but are not limited to, calcific
tendinopathy of the shoulder, elbow tendinopathy (lateral/medial
epicondylitis), carpal tunnel syndrome (CTS), greater trochanteric pain
syndrome (GTPS), fractures and delayed unions/nonunions, osteonecrosis of the
femoral head (ONFH), and patellar tendinopathy (PT).

The mechanism by which ESWT achieves a therapeutic intervention in
musculoskeletal conditions is not completely known. Numerous hypotheses have
been proposed:

  * ESWT may disrupt fibrous tissue allowing for the subsequent promotion of revascularization and healing of tissue.
  * Direct and indirect effects of the shock waves may damage cell membranes; reducing the ability of nociceptors to transmit pain signals11 and/or promote healing.
  * Shock waves break up calcium deposits, loosen structures, and promote resorption of calcium; thereby decreasing pain and improving function. 

This A/B MAC considers ESWT (high energy) not reasonable and necessary for the
treatment of musculoskeletal conditions and therefore not covered.

**Calcific tendinopathy of the shoulder:**

Daecke, et al. (2002) conducted a study to evaluate the long-term effects and
any complications of ESWT for calcific tendinitis (CT) of the shoulder.9 The
4-year outcome was determined in a prospective study of 115 patients who
presented with painful CT for >12 months and conservative treatment
(physiotherapy and subacromial steroid injections) for at least 6 months
without effect. For this study, the CT patients had persistent shoulder pain
associated with calcareous deposits in the supraspinatus or infraspinatus
tendon. Patients were treated with high-energy ESWT by 2 different protocols.
One day prior to ESWT, each patient underwent an anteroposterior x-ray in
internal and external rotation of the shoulder and a functional examination of
the shoulder was performed and documented with use of the Constant-Murley (CM)
score. One session (group A, n = 56) or 2 sessions (group B, n = 59) of high-
energy shockwave therapy were administered to each patient. The shockwave
intensity was increased, within the first 300 impulses, from low energy up to
an energy flux density (EFD) of 0.3 mJ/mm2. Outcome was determined by
functional examination, x-rays of the shoulder, and the patients' own
assessments at 3 months, 6 months, and 4 years post-therapy. Results at
6-months showed that the level of success achieved in pain relief and CM score
was energy-dependent and that there were significant differences in radiologic
changes between the groups. Four years following ESWT, 20% of the entire
patient population had undergone surgery on the involved shoulder. The effects
of ESWT not followed by any other therapy within the first 6 months were
evaluated in 59% (n = 68) of the original 115 patients. Frequency of
subjective success (increase in pain relief) was seen in 78% of patients in
group A and 87% in group B. The CM score increased from a mean of 45 pre-
treatment to 88 in group A and 85 in group B post-treatment. Radiologic
changes were found in 93% of patients in each group. The authors concluded
that the failure rate after ESWT was high, but the treatment was successful
for 70% of the patients in this study and no long-term complications were
seen.

Ioppolo, et al. (2012) noted that limited evidence was available for the
useful range of ESWT doses in the treatment of supraspinatus calcifying
tendinitis (SCT). The authors published a single-blind randomized clinical
trial to compare 2 different ranges of EFD in treatment of SCT with ESWT.12
Forty-six patients with SCT were randomized to 2 groups that received
different therapeutic energy doses of ESWT: (1) group A (n=23) received ESWT
at an energy level of 0.20 mJ/mm2, and (2) group B (n=23) received ESWT at an
energy level of 0.10 mJ/mm2. Both groups received 2,400 pulses once a week for
4 weeks. The change in mean CM score from baseline to 3 and 6 months was the
primary endpoint. The change in the mean visual analog scale (VAS) scores from
baseline to 3- and 6-months post-treatment and radiographic change in size of
calcium deposits were evaluated as secondary endpoints. At 12 months, pain
relief was assessed using a numeric rating scale. Results showed that
significant clinical improvement based on mean CM scores was observed after 6
months in group A (sample mean=79.43, SD=10.33) compared with group B (sample
mean=57.91, SD=6.53). Also, after 6 months, a significant decrease in VAS
scores was found in group A (sample mean=2.09, SD=1.54) compared with group B
(sample mean=5.36, SD=0.78). The disappearance of calcific deposits was
similar in both groups. The authors concluded that for treatment of SCT, an
energy level of 0.20 mJ/mm2 for ESWT appears to be more efficacious than an
energy level of 0.10 mJ/mm2 regarding pain relief and functional improvement.
However, the results are limited secondary to small sample size and lack of a
control group.

A prospective randomized trial of calcifying tendinitis of the rotator cuff by
Albert, et al. (2007) compared the efficacy of dual treatment sessions
delivering 2500 extracorporeal shock waves at either high- or low-energy.1
Patients were eligible for the study if they had > 3 months history of
calcifying tendinitis of the rotator cuff, with calcification measuring 10 mm
or more in maximum dimension. The change in the CM score was the primary
outcome measure. Eighty patients were enrolled in the study (40 in each
group). Patients were re-evaluated at a mean of 110 (41 to 255) days post-
treatment when the increase in CM score was significantly greater (t-test, p =
0.026) in the high-energy treatment group than in the low-energy group. In the
high-energy group, the improvement from baseline was significant with a mean
gain of 12.5 (-20.7 to 47.5) points (p<0.0001). In the low-energy group, the
improvement was not significant. Total or subtotal resorption of the
calcification took place in 6 patients (15%) in the high-energy group and 2
patients (5%) in the low-energy group. The investigators concluded that high-
energy shock-wave therapy significantly improves symptoms in refractory
calcifying tendinitis of the shoulder after 3 months of follow-up; however,
the calcific deposit remains unchanged in size in most patients.

Verstraelen, et al. (2014) noted that ESWT was a possible alternative to
surgery after failure of conservative treatment for calcifying tendinitis of
the shoulder. The authors performed a systematic review and meta-analysis of
randomized trials to compare the CM score and amount of resorption of
calcifications in patients treated with high-energy ESWT vs. those treated
with low-energy ESWT at 3 and 6 months.21 Medline (through PubMed), EMBASE
(through OVID), Cinahl (through EBSCO), Web of Science, and the Cochrane
Central Register of Controlled Trials (CENTRAL), were systematically searched.
Included studies consisted of randomized controlled trials (RCTs) that
compared high-energy ESWT (>0.28 mJ/mm2) with low-energy ESWT (<0.08 mJ/mm2).
The primary outcome measure, the CM score, was determined by comparing mean
functional outcome scores between the groups. Secondary outcomes were
determined using odds ratios, when appropriate data were pooled. Five RCTs
(359 participants) were included. All 5 RCTs, showed greater improvement in
functional outcome (CM score) for patients treated with high-energy ESWT vs.
treatment with low-energy ESWT at 3 and 6 months. The 3-month mean difference
was 9.88 (95% CI, 9.04-10.72, p<0.001; 6-month data could not be pooled).
Also, high-energy ESWT more often resulted in complete resorption of the
calcium deposits at 3 months. The corresponding odds ratio was 3.40 (95% CI,
1.35-8.58) and p = 0.009 (6-month data could not be pooled). High-energy shock
wave therapy appears to be more likely to result in improved CM score and
resorption of the calcium deposits compared with low-energy therapy.

Bannuru, et al. (2014) conducted a systematic review using CENTRAL, EMBASE,
Web of Science, and Google Scholar (n=28 RCTs/1307 subjects) to assess the
efficacy of ESWT in patients with CT (n=1134) and non-CT (n=173).4 Outcome
measures included pain (VAS), functional assessment (CM score), and resolution
of calcium deposits, which was evaluated only in CT trials. Of the 28 RCTs, 20
compared different ESWT energy levels to placebo and 8 compared ESWT to other
treatments. The quality of trials was reported as variable and generally low.
Trials included multiple sources of bias and heterogeneity, including
different ESWT regimens and ESWT devices. The heterogeneity of the included
trials and general paucity of similar trials resulted in the inability of the
authors to perform a meta-analysis of these studies. Results show that high-
energy ESWT (EFD 0.28 mJ/mm2) was efficacious for treatment of CT of the
shoulder regarding reducing pain, improving function, and inducing resorption
of calcifications. Lower-energy ESWT (EFD <0.28 mJ/mm2) was not as effective
as high-energy ESWT; however, it did improve shoulder function in patients
with CT. Results for pain and reduction in calcification were inconclusive
with low-energy ESWT. Irrespective of energy dose, ESWT did not appear to be
efficacious in treating non-CT. Adverse effects of ESWT included localized
swelling, redness, or small hematomas and were reported to be dose dependent.
The authors concluded that high-energy ESWT appears effective for improving
pain and shoulder function in chronic calcific shoulder tendinitis and can
result in complete resolution of calcifications. However, larger RCTs as well
as standardization of energy levels and treatment protocol were needed to
further define the role of ESWT for treating CT of the shoulder.

Peters, et al. (2004) investigated clinical (pain, mobility) and radiological
(resolution of calcium deposits) efficacy of different energy levels of ESWT
in CT of the shoulder.17 The study included 90 subjects with radiographically
verified CT of 1 shoulder, mean age 52+/-6 years (range 29-65 years;
females:males=55:35). All subjects had symptoms for at least 6 months,
substantial restriction of shoulder mobility, and pain that required taking
anti-inflammatory drugs. Calcium deposits were type I or type II and ranged
from 1 cm to 3 cm in diameter. Subjects were divided into 3 groups to receive
different energy levels of ESWT (E1=0.15 mJ/mm2, E2=0.44 mJ/mm2) or sham
treatment. The number of pulses per session (n=1,500) was kept constant in
groups E1 and E2. Anesthesia was not used in any of the protocols. In all
groups, patients in each group received treatments at intervals of 6 weeks
until symptoms had resolved, until 5 treatments had been applied, or until
patients dropped out of the program. Group E1 (n=30) had significantly
(t=7.77; p<0.001) less pain during ESWT (mean: 6.91.6, 10-point scale) than
patients treated with the higher energy level E2 (mean: 9.61.0) as well as
significantly (p<0.001) more treatments (mean: 4.10.8) than patients
receiving the higher-energy protocol E2 (mean: 1.20.4). At 6-month follow-up,
group E1 had residual calcification and recurrence of pain (87%). Subjects in
group E2 (n=31) had no residual calcification or recurrence of pain. Sham
treatment (n=29) had no effect. Adverse effects included a small number of
hematomas (2 in E1, 6 in E2). ESWT in CT of the shoulder appears to be
effective. It did not seem to have significant side effects at an energy level
of E=0.44 mJ/mm2.

A meta-analysis performed by Louwerens, et al. (2014) assessed the short to
midterm efficacy of minimally invasive treatments in the management of
calcifying tendinopathy of the shoulder cuff.16 A systematic literature search
identified 20 studies (1544 participants). The primary end points were
identified as function, pain, and total resorption rates. Grades of
Recommendation, Assessment, Development, and Evaluation (GRADE) was used to
assess the quality of evidence. Common methodological flaws were related to
randomization. Studies showed there is moderate-quality GRADE evidence that
high-energy ESWT has a significant effect on pain relief and functional status
compared with other interventions.

Arirachakaran, et al. (2017) conducted a systematic review and meta-regression
to compare clinical outcomes between treatments for CT, which included ESWT,
ultrasound-guided percutaneous lavage (UGPL or barbotage), subacromial
corticosteroid injection (SAI), and combined treatment.3 RCTs were identified
using PubMed and Scopus search engines, and 7 of 920 studies identified were
eligible. Outcomes of interest were CM score, pain VAS, size of calcium
deposit, and adverse effect. Results showed that ESWT significantly improved
CM score and VAS when compared to placebo. Barbotage plus ESWT significantly
improved CM score, VAS and decreased size of calcium deposit when compared to
ESWT alone. Barbotage plus SAI significantly improved CM score and decreased
size of calcium deposit when compared to SAI. No difference in adverse effects
were found in all treatment groups. Multiple active treatment comparisons
indicated that barbotage plus SAI significantly improved VAS and size of
calcium deposit when compared to other groups, while barbotage plus SAI
improved CM score when compared to other groups; however, there was no
statistically significant difference. The network meta-analysis proposed that
combined ultrasound (US)-guided needling and SAI significantly decreased
shoulder pain VAS, improved CM score, and decreased the size of calcium
deposits, while also lowering risks of adverse event when compared to
barbotage plus ESWT or ESWT plus SAI. The authors concluded that the evidence
suggests that UGPL is the treatment of choice for nonsurgical options of
treatment in CT of the shoulder.

Another systematic review by Surace, et al. (2020) with broader inclusion
criteria reported trends toward improvement in rotator cuff disease with ESWT
but emphasized that all trials were susceptible to bias.18 The authors
concluded that based upon the currently available low- to moderate-certainty
evidence, there were very few clinically important benefits of ESWT, and
uncertainty surrounding its safety. They highlighted that wide clinical
diversity and varying treatment protocols suggests that there is uncertainty
regarding whether some trials tested subtherapeutic doses, which could
possibly underestimate any potential benefits. The authors recommended that a
standard dose and treatment protocol be decided upon before further research
is conducted. Development of a core set of outcomes for trials of rotator cuff
disease and other shoulder disorders would help to facilitate the ability to
synthesize the evidence.

**Elbow tendinopathy:**

Several treatments have been proposed to treat epicondylitis. Dingemanse, et
al. (2014) conducted an evidence-based overview of the effectiveness of
electrophysical modality treatments, including US, laser, electrotherapy,
ESWT, transcutaneous electrical nerve stimulation (TENS) and pulsed
electromagnetic field therapy, for both medial and lateral epicondylitis
(LE).10

METHODS Searches were performed in PubMed, EMBASE, CINAHL and Pedro to
identify RCTs and systematic reviews. Two reviews and 20 RCTs evaluated the
different electrophysical regimens for treatment of LE. Results demonstrated
moderate evidence for the effectiveness of US vs. placebo on mid-term follow-
up. US plus friction massage showed moderate evidence of effectiveness vs.
laser therapy on short-term follow-up. Laser therapy showed moderate evidence
of effectiveness vs. plyometric exercises on short-term follow-up. For all
other modalities, including ESWT, studies showed only limited/conflicting
evidence for effectiveness.

Buchbinder, et al. (2006) performed a systematic review of RCTs to determine
the efficacy and safety of ESWT for treatment of lateral elbow pain.5 Nine
placebo-controlled trials (n=1006) and 1 trial of ESWT vs. steroid injection
(n=93) were included. The 9 placebo-controlled trials reported conflicting
results. When available data were pooled, no significant benefit of ESWT over
placebo could be found; weighted mean difference for improvement in pain (on a
100-point scale) from baseline to 4-6 weeks (pooled analysis of 3 trials,
n=446) was -9.42 (95% CI -20.70 to 1.86). Two pooled results favored ESWT;
relative risk of treatment success (at least 50% improvement in pain with
resisted wrist extension at 12 weeks) in comparison to placebo (pooled
analysis of 2 trials, 192 participants) was 2.2 (95% CI 1.55 to 3.12).
However, this result was not supported by 4 other trials that were unable to
be pooled. Steroid injection was determined to be more effective than ESWT at
3 months after the end of treatment assessed by a reduction of pain of 50%
from baseline [21/25 (84%) vs. 29/48 (60%); p<0.05]. The authors concluded
that ESWT provides negligible benefit in terms of pain and function in lateral
elbow pain.

Vulpiani, et al. (2015) conducted a single-blinded RCT (n=80) comparing the
effectiveness of ESWT (n=40) to cryoultrasound (n=40) in patients with chronic
lateral epicondylitis over a 12-month period.22 Inclusion criteria were adults
18 to 75 years old, diagnosis of chronic lateral epicondylitis within at least
3 months, intensity of pain  5 on the VAS, and failure of previous
conservative treatments. The primary outcome measure was a difference of 2
points in pain recorded on the VAS during the Cozen test for the ESWT group
vs. the cryoultrasound group. The secondary outcome measure was the number of
patients who achieved at least 50% satisfactory results, considered as the sum
of excellent and good scores in the Roles and Maudsley score, at 3, 6 and 12
months of follow-up. Results showed that significant differences between
groups for the VAS score were noted at 6 months (p<0.001) and 12 months
(p<0.001) in favor of ESWT group. The satisfaction rate required at 50% was
only achieved in the ESWT group in the follow-up at 6 (62.5%; p<0.003) and 12
(70.0%; p<0.001) months. Pain at the tolerability limit was reported by all of
those treated with ESWT. The authors concluded that ESWT has better clinical
therapeutic results at 6- and 12-month follow-up compared to cryoultrasound.
However, limitations acknowledged for this study include the lack of a placebo
group to demonstrate the natural course of the condition and absence of hand
grip strength and finger pinch analysis. Additional investigation is needed
for confirmation of the study results.

Yan, et al. (2019) conducted a meta-analysis (n=5 RCTs/233 patients) comparing
the efficacy of ESWT and US in relieving pain and restoring the functions of
tennis elbow following tendinopathy.23 The results showed a significantly
lower VAS score of pain in the ESWT group at 1, 3, and 6 months (p=0.0001;
p<0.00001; p<0.0001, respectively) compared to US. Additionally, the grip
strength was significantly higher 3 months after ESWT (p<0.00001) than in the
US group. No statistically significant difference was found in the scores of
the elbow function after 3 months (p=0.13); however, the subjective scores of
elbow functions were improved in the ESWT group (p=0.0008) compared to the US
group. The authors concluded that ESWT offers more effective therapy for
lateral epicondylitis than ultrasound therapy (UST). However, limitations of
this study included small patient population, side effects of ESWT and US were
not evaluated during follow-up, and the high heterogeneity among the results
weakens. Longer studies are warranted to evaluate the efficacy of ESWT and US
on tennis elbow function and to evaluate the optimal therapeutic setting of
ESWT.

**Carpal tunnel syndrome:**

Kim, et al. (2019) conducted a systematic review and meta-analysis (n=6
RCTs/281 subjects) evaluating whether ESWT can improve symptoms, functional
outcomes, and electrophysiologic parameters in CTS.13 RCTs were eligible for
inclusion if there was at least 3 months of follow-up that described the
effect of ESWT on CTS. Follow-up ranged from 12-24 weeks. ESWT showed
significant overall effect size compared to the control (pooled standardized
mean difference (SMD) = 1.447; 95% CI, 0.439-2.456; p=0.005). Symptoms,
functional outcomes, and electrophysiologic parameters all improved with ESWT.
However, no obvious difference between the efficacy of ESWT and local
corticosteroid injection was found (pooled SMD = 0.418; 95% CI, -0.131-0.968;
p=0.135). The authors concluded that ESWT appears to improve symptoms,
functional outcomes, and electrophysiologic parameters in CTS; however, data
on the long-term effects of ESWT are lacking and further research is needed to
confirm the long-term effects and the optimal ESWT protocol for CTS.
Limitations were noted to be small sample size and the patient population was
limited to those with mild to moderate CTS. No studies aimed to investigate
the effect of ESWT on severe CTS.

**Other musculoskeletal conditions:**

A RCT conducted by Carlisi, et al (2019) investigated whether ESWT is an
efficacious in the treatment of GTPS.7 Patients (n=50) were randomized into
the ESWT study group (n=26) or an UST control group (n=24). Patients in the
ESWT group were treated with focused ESWT once weekly for 3 consecutive weeks.
Patients in the control group were treated with UST daily for 10 consecutive
days. The patients enrolled in the study met the following criteria:
unilateral hip pain persisting for 6 weeks or longer; physical examination
showed pain to palpation in the greater trochanteric area and pain with
resisted hip abduction; gluteal tendinopathy, in the absence of full thickness
tears; no corticosteroid injections or other conservative therapies (except
pharmacological pain treatments), since the onset of the current pain episode;
ESWT was not contraindicated; absence of clinical signs of lumbar
radiculopathy on physical examination; no hip or knee osteoarthritis, no
previous fractures or surgery in the affected limb, and no rheumatologic
diseases. Outcomes measured hip pain and lower limb function using a numeric
rating scale (p-NRS) and the Lower Extremity Functional Scale (LEFS scale),
respectively. Patients were followed up at 2 months after the first treatment
session and again 6 months later. Results showed a significant pain reduction
over time for the study group and the control group, the ESWT proving to be
significantly more effective than UST at the 2-month follow-up (2.08 vs. 3.36;
p < 0.05) and at the 6 month follow-up (0.79 vs. 2.03; p < 0.05). A marked
improvement of the LEFS total score was observed in both groups. Results
showed no statistical differences between groups. The authors concluded that
ESWT is effective in reducing pain in the short and mid-term; however, it does
not appear to be superior to UST. Limitations were noted to include small
patient population, short term follow-up, and unblinding of the patients.

Zelle, et al. (2010) performed a systematic review (n=11 studies/924 patients)
for the use of ESWT in the treatment of fractures and delayed
unions/nonunions.24 Eleven relevant studies met inclusion criteria (10 case
series and 1 RCT). The overall union rate in patients with delayed
union/nonunion was 76% (95% CI; 73%-79%) and ranged from 41% to 85%.
Limitations included the paucity of higher-level evidence and comparative
data. The authors concluded the ESWT seems to stimulate the healing process in
delayed unions/nonunions; however, future studies need to investigate how ESWT
compares with other treatment approaches and if different anatomic fracture
locations may demonstrate different success rates. Also, the optimal treatment
dose needs to be identified in further investigations. The authors also noted
that the natural history of these lesions remains unclear, and it may be
assumed that some delayed unions may have healed using other non-operative
therapies.

Cacchio, et al. (2009) performed a double-blind RCT (n=126) comparing ESWT to
surgery for the treatment of long bone nonunions.6 Patients were randomized
either ESWT (Groups 1 and 2) or surgical treatment (Group 3). The patients in
the ESWT groups received 4 treatments with 4000 impulses of shock waves with
an EFD of 0.40 mJ/mm2 (Group 1) or 0.70 mJ/mm2 (Group 2). Radiographic results
(the primary outcome) and clinical results (the secondary outcomes) were
determined before and 3, 6, 12, and 24 months post-treatment. At 24 months,
there were no significant differences found in clinical outcomes.

Alves, et al. (2009) conducted a systematic review (n=5 studies) of the
evidence examining the use of ESWT for treatment of ONFH.2 Of the 5 studies, 2
were RCTs, 1 open label study, 1 comparative prospective study, and 1 was a
case report. The review showed that there are no controlled and double-blind
studies regarding the efficacy of ESWT in the treatment of ONFH. The
noncontrolled studies appeared to demonstrate some favorable result, but the
authors did note the lack of well-designed studies.

Chen, et al. (2009) investigated patient (n=17) functional outcomes of total
hip arthroplasty (THA) for late ONFH in 1 hip and ESWT for early stages of
ONFH in the opposite hip.8 Results showed that both THA and ESWT had
significant improvements in pain score and Harris hip score (P<0.001).
However, ESWT did appear to offer a significant difference in the magnitudes
of improvement when compared to THA (P<0.001). Subjectively, patients rated
ESWT better than THA in 13 cases (76.5%), ESWT comparable to THA in 4 cases
(23.5%), and no patients rated THA better than ESWT. The authors concluded
that short-term functional outcomes of hips treated with ESWT for early hip
necrosis seem to be more favorable when compared to THA for late hip necrosis
in patients with bilateral hip disease. It should be noted that before
surgery, the THA side showed more pain and less function than the ESWT side
(P<0.001). Limitations of the study included a small number of cases, short
follow-up, non-blinded patient selection, and potential bias in clinical
assessment given anticipation of more pain and disability in the THA side
prior to surgery. Longer-term results are needed to validate the efficacy
findings in this study.

ESWT has been proposed for other conditions, including PT. Thijs, et al.
(2017) performed a RCT to evaluate the efficacy of a combined treatment of
ESWT and eccentric training compared with sham-shockwave therapy (placebo) and
eccentric training in patients with PT after 24 weeks.20 The authors found no
significant differences for the primary and secondary outcome measures.
Additional studies14,15,19 show low to moderate evidence for use of ESWT in
the treatment of PT. These studies are also limited with small sample sizes
and heterogeneity secondary to varying study designs and application
protocols.

The available evidence suggests that further research is needed to establish
the efficacy and safety of high energy ESWT in the treatment of
musculoskeletal conditions. The uncertainty associated with this intervention
is highlighted by the wide clinical diversity and varying treatment doses and
protocols as evidenced in the current literature.