**Initial Trigger Point Injection (TPI)**  
Trigger point injections will be considered medically reasonable and necessary
to treat myofascial pain caused by trigger points when all the following
requirements are met:

  1. There is a focal area of pain in the skeletal muscle.
  2. There is clinical evidence of a trigger point defined as pain in a skeletal muscle that is associated with a at least 2 of the following: a hyperirritable spot and/or taut band identified by palpation and possible referred pain is present **AND**
  3. The physical examination identifies a focal hypersensitive bundle or nodule of muscle fiber harder than normal consistency with or without a local twitch response and referred pain **AND**
  4. Non-invasive conservative therapy is not successful as first line treatment **OR** movement of a joint or limb is limited or blocked **OR** the TPI is necessary for diagnostic confirmation.

**Subsequent TPI**

Repeat Trigger point injections will be considered medically reasonable and
necessary to treat myofascial pain syndrome when all the following
requirements are met:

  1. There is a positive response defined as providing a minimum of 50% relief of primary (index) pain after the TPI measured by the SAME pain scale* at baseline and post-injection **AND**
  2. Consistent pain relief from previous TPI lasting at least 6 weeks (Manchikanti et al. 2001) **AND**
  3. The pain has reoccurred and is causing functional limitations measured by functional scale obtained at baseline and after TPI which demonstrates at least 50% improvement from the previous TPI.

*Note: The scales used to measure pain and/or disability must be documented in the medical record. Acceptable scales include but are not limited to: verbal rating scales, Numerical Rating Scale (NRS) and Visual Analog Scale (VAS) for pain assessment, and Pain Disability Assessment Scale (PDAS), Oswestry Disability Index (ODI), Oswestry Low Back Pain Disability Questionnaire (OSW), Quebec Back Pain Disability Scale (QUE), Roland Morris Pain Scale, Back Pain Functional Scale (BPFS), and the PROMIS profile domains to assess function.

Limitations: No more than three (3) TPI sessions will be reimbursed per
rolling 12 months.

**Requirements:**

  1. Patient should be part of an ongoing conservative treatment program, and documentation to support the patient is actively participating in a rehabilitation program, home exercise program or functional restoration program.
  2. There should be at least 6 weeks duration before TPI is repeated in the same location.
  3. Trigger point primary index pain must be measured prior to the injection at the beginning of the session.
  4. The post procedure pain level must be measured after the TPI at the conclusion of the session using the same scale* utilized at baseline.
  5. When documenting the percentage of pain relief from the primary (index) pain compared to the post-injection pain levels, it is insufficient to report only a percentage of pain relief and/or a nonspecific statement of the duration of pain relief. The documentation should include a specific assessment of the duration of relief being consistent or inconsistent with the agent used for the injection and the specific dates the measurements were obtained using the SAME pain scale* used at baseline.
  6. When documenting the ability to perform previously painful movements and activities of daily living (ADLs) it is insufficient to provide a vague or nonspecific statement regarding the improvement of previously painful movements and activities of daily living (ADLs). The documentation should include a functional assessment to show clinically meaningful improvement with painful movements and ADLs, if this metric is used to justify the efficacy of the TPI procedure. Providers should use established and measurable goals and objective scales to assess functionality and ADLs measures.

**Limitations:**

  1. A TPI involves the use of a local anesthetic and does not include injections of biologics (e.g., platelet rich plasma, stem cells, amniotic fluid, etc.) and/or any other injectates.
  2. It is not considered medically reasonable and necessary to perform TPIs into multiple muscle groups in different anatomical regions during the same session.
  3. It is not considered medically reasonable and necessary to perform multiple blocks (ESI, sympathetic blocks, facet blocks etc.) during the same session as TPIs injections.
  4. Trigger points injections for treatment of headache, neck pain or low back pain in absence of actual trigger points, diffuse muscle pain, chronic pain syndrome, lumbosacral canal stenosis, fibromyalgia, non-malignant musculoskeletal pain, complex regional pain syndrome, sexual dysfunction/ pelvic pain, whiplash, neuropathic pain, and hemiplegic shoulder pain are considered investigational and therefore are not considered medically reasonable and necessary.
  5. Use of fluoroscopy or MRI guidance for performance of TPIs is not considered reasonable and necessary.
  6. The use of ultrasound guidance for the performance of TPIs is considered investigational.
  7. Trigger point injections used on a routine basis, e.g., on a regular periodic and continuous basis, for patients with chronic non-malignant pain syndromes are not considered medically necessary.

**Provider Qualifications:**

The Medicare Program Integrity Manual states services will be considered
medically reasonable and necessary only if performed by appropriately trained
providers.

Patient safety and quality of care mandate that healthcare professionals who
perform TPI injections/procedures for chronic pain (not surgical anesthesia)
are appropriately trained and/or credentialed by a formal residency/fellowship
program and/or are certified by either an accredited and nationally recognized
organization or by a post-graduate training course accredited by an
established national accrediting body or accredited professional training
program whose core curriculum includes the performance and management of the
procedures addressed in this policy. Credentialing or privileges are required
for procedures performed in inpatient and outpatient settings.2

All aspects of care must be within the provider's medical licensure and scope
of practice. Reimbursement for procedures utilizing imaging techniques may be
made to providers who meet training requirements for the procedures in this
policy only if their respective state allows such in their practice act and
formally licenses or certifies the practitioner to use and interpret these
imaging modalities (ionizing radiation and associated contrast material,
magnetic resonance imaging, ultrasound). At a minimum, training must cover and
develop an understanding of anatomy and drug pharmacodynamics and kinetics as
well as proficiency in diagnosis and management of disease, the technical
performance of the procedure, and utilization of the required associated
imaging modalities.

Definitions

**Anatomical Region** - An area of the body defined by structures which are
palpable or visible. Typically described as cervical region, lumbar region,
scapular region, thoracic region, cephalic region, facial region, etc.

**Dry needling** \- a technique that involves the insertion of solid filament
needles into the skin and underlying tissue to disrupt pain sensory pathways
and relax contracted fibers.

**Fibromyalgia** - a chronic pain syndrome which presents with tender points,
somatic symptoms and widespread musculoskeletal pain associated with the
development of peripheral and central sensitization.

**GRADE** - A system developed by the GRADE Working Group to address the
shortcomings of present grading systems in healthcare. The GRADE system uses a
common, sensible, and transparent approach to grading the quality of evidence.
The results of applying the GRADE system to clinical trial data are displayed
in a table known as a GRADE profile.

**Muscle group** \- a group of muscles that are contiguous and that share a
common function, e.g., flexion, stabilization or extension of a joint. Muscles
that are widely separated anatomically and have different functions may be
considered to be separate muscle groups.

**Myofascial pain syndrome** - a chronic pain syndrome characterized by
trigger points associated with the development of peripheral and central
sensitization.

**Nerve block** \- an invasive procedure where medication is injected directly
into or around a nerve. Rigdon issue with injection into the nerve

**Session** - A time period, which includes all procedures (i.e., medial
branch blocks (MBB), intraarticular injections (IA), facet cyst ruptures, and
RFA ablations) performed during one day.

**Tender Point** \- areas of tenderness occurring in muscles, muscle-tendon
junction, bursa or fat pad.3

**Tendon sheath injection** - an invasive procedure where medication is
injected into a tendon sheath.

**Trigger point** \- pain in a skeletal muscle that is associated with a at
least two of the following: a hyperirritable spot, taut band and referred
pain.3,4

**Trigger point injection** \- an invasive procedure where medication is
injected directly into a trigger point.5

**Background**

Trigger points are discrete, focal hyperirritable spots located in a taut band
of skeletal muscle. They are characterized by pain with palpation and can also
produce referred pain described as tenderness, motor dysfunction and autonomic
phenomena.4,5 Trigger points are usually (but not always) accompanied by other
hypertonic muscle groups. On physical exam palpation of the hypersensitive
bundle or nodule of muscle fiber is harder than normal consistency. In
addition to elicitation of pain with palpation there is often an associated
local twitch response.5

Trigger point injections involve the insertion of a needle into muscle bands,
muscle knots and trigger points with an intramuscular injection which is
typically local anesthetic.5 Dry needling is a similar technique performed
without the intramuscular injectant and will not be considered in this local
coverage determination (LCD).

A 2017 International Consensus sought to create a diagnostic criterion for the
diagnosis of trigger points.4 Prior to this consensus 19 different criteria
were found in the literature resulting in a call for a standardized
definition. Using a Delphi survey experts endorsed that 2 palpatory findings
and 1 symptom were central criteria for trigger point diagnosis by more than
70% of the experts which included a taut band (N=56, 93%), a hypersensitive
spot (N=46, 76.5%), and referred pain (N=43, 71.5%). The experts agreed that
referred pain could include pain spreading to a different region, deep or dull
pain, as well as some tingling or burning sensation within the region.4

A Multi-jurisdictional contract advisory committee meeting of subject matter
experts (SMEs) was convened on 4/27/23 regarding trigger point injections. The
transcript and audio are available on each MACs website. The panel consisted
of experts in anesthesiology, physical medicine and rehabilitation,
musculoskeletal radiology, rheumatology, certified nurse anesthetist, and a
physical therapist with representation throughout the country and included
representation from major pain societies. The panel will be referred to as
SMEs, and their input incorporated through the review to correlate the
evidence with expert input.

A SME summarized the following: "The nonspecific diagnosis (note, for example
the difficulty in distinguishing a "tender point" and "trigger point") and
variability of clinical measurement make research for TPI inconsistent. The
efficacy of TPI is not clear for the population as a whole, but there is
benefit in specific patients. Likely, a reasonable approach is to approve TPI
for limited, short courses in which clinicians are asked to provide
documentation of benefit prior to continued therapy. It is a low-cost
therapeutic approach with a high safety index and seems reasonable with
adequate documentation."

**Conservative Management**

The SME representing the American Physical Therapy Association explains there
is moderate to high quality evidence for physical therapy depending on the
condition or diagnosis and they acknowledge in some cases TPIs aid in
achieving patient goals. Evidence to support early and direct access to
physical therapy (PT) as first course of care is available for low back pain,
neck pain and osteoarthritis.

PT literature supports the concept that early PT can avoid need for
injection.5

**Trigger Point Injections**

Trigger point injections are administered directly into the taut muscle band.
The mechanism of how trigger points work is not clear however it is postulated
that the physical act of placing the needle into the muscle triggers an
inflammatory response and that improvement can be made regardless of the
injectate just from the physical response to the needle.

Injectants including sterile saline, local anesthetics (LA), and a variety of
other agents have been investigated.

SMEs report there is little evidence to support corticosteroids alone or in
addition to LA improve outcomes. Another SME shared that use of steroids is
not uncommon in rheumatology practice for TPI. Concerns for side effects
associated with corticosteroids including hyperglycemia, weight gain, effect
on bone mineral density if long term and hypertension were discussed.

The literature reports that the duration of effect after a trigger point
injection is variable. The literature has wide variability in protocols
ranging from repeating injections weekly to up to 3-4 months. The SMEs agree
that most often injections are not being administering more frequently than
every 3 months.

**Image Guidance**

There are no standard criteria regarding imaging for trigger point injections.
Trigger points are commonly identified by manual palpation of the trigger
point and elicitation of the local twitch response both of which and are
performed without imaging. In cases of deep muscles that are not palpable some
investigators report a benefit to ultrasound to visualize the twitch response
and ensure the injection has been localized to the trigger point. Evidence to
support this role is limited to case reports6,7, case studies8,9 and 1
exploratory study.10 Subject matter experts felt that there are individualized
cases where ultrasound may provide benefit.

A descriptive (exploratory) study was conducted to describe the ultrasound
characteristics of myofascial trigger points and adjacent soft tissue. The
study included physical exam findings, pressure algometry, and 3 types of
ultrasound imaging including grayscale, vibration sonoelastography and
Doppler. Ultrasounds were performed by a team blinded to the physical
findings. They concluded that the myofascial trigger points appeared as focal,
hypoechoic regions on 2D ultrasound (grayscale), had higher tissue image score
compared to normal myofascial tissue and retrograde flow in diastole
indicating a higher resistive vascular bed. The authors concluded that
ultrasound imaging techniques can be used to distinguish myofascial tissue
containing trigger points from normal myofascial tissue and enable
visualization and some characterization of the trigger points and adjacent
soft tissue.10 Limitations of this study include small sample size, lack of
standardization of scan technique and the lack of a control group. Additional
studies further define ultrasound findings in the presence of trigger
points.11

A 2019 study compared ultrasound guided TPI (n=21) to blind injection
technique (n=20) using shear wave elastography for measurement of stiffness at
trigger point site for trapezius myofascial pain syndrome. The authors
reported a statistically significant difference in Visual Analog Score, Neck
Disability Index and Shoulder Pain and Disability Index scores at 4 weeks from
baseline between the 2 groups (p = 0.003, 0.012, and 0.018, respectively). The
authors concluded that the ultrasound guided TPI are more effective than the
blind injections.12 Limitations include small sample size, lack of control
group or standardization of ultrasound technique or findings.

A 2008 paper is a descriptive report introducing the technique of ultrasound
for guidance of TPIs. In this report the authors emphasize that correct needle
placement into the trigger point is vital to prevent complications and improve
efficacy of the procedure. This can be challenging in obese patients and
misguided or misplaced injection is a risk for pneumothorax. The authors go on
to explain that ultrasound guidance could help to avoid potential
complications and may increase efficacy however this was not investigated in
this report or subsequent reports, so this hypothesis has not been
confirmed.13

SMEs felt there is benefit of image guidance in areas at high risk for
pneumothorax, a reported complication of TPI and injections in the thoracic
zone should be done with image guidance to improve safety. Also, in highly
vascular areas and deep tissue to ensure proper location.

**Myofascial Pain Syndrome (MPS)**

SME representing the Coalition of State Rheumatology Organizations state that
rheumatologists diagnose and manage a wide array of musculoskeletal conditions
including MPS, which is essentially "knots" in the muscles that do not
release. They comment that despite lack of external validity myofascial pain
syndrome caused by trigger points is an accepted condition.14 They explain TPI
with local anesthetic (LA) and sometimes corticosteroid to reduce inflammation
is an effective tool.

A 2023 review of the literature concludes that while randomized trials have
found statistically significant improvement related to TPI, the studies are
limited by the low number of participants, lack of blinding, potential for
placebo effect, and lack of post treatment follow up. The studies are
inconclusive regarding a single pharmacological agent proving superiority to
another. Evidence rating B is inconsistent or limited quality patient-
orientated evidence. The following received an evidence score of B: placebo
effect may be the underlying source of pain of relief from TPI. Massage and
physical therapy should be considered first line less invasive treatment for
TPI and routine use of trigger point injections is not supported in clinical
trials. The authors advocate for reserving trigger point injections for
myofascial pain that is refractory to other measures and management as part of
a comprehensive, multimodal and team-based approach to patients with
myofascial pain.15

A 2019 systematic review and meta-analysis was conducted to compare the
effectiveness of local anesthetics and botulinum toxin-A (BTX-A) in patients
with myofascial pain by: (1) assessing the effects of local anesthetics and
BTX-A on reported pain over several follow-up periods; (2) assessing the
effects of single and multiple injection sessions of each injectate type on
changes in reported pain; and (3) to determine whether reported pain differs
based on the region of injection for each type of injectate. A comprehensive
literature search was performed utilizing EMBASE, Cochrane CENTRAL, and
Medline, which produced 33 studies that were included for analysis. A total of
18 articles assessed the effect of local anesthetic trigger point injections
and 16 assessed the effect of BTX-A injections on reported pain. The search
included RCTs, control trials, and randomized trials. The visual analog scale
(VAS) and the Neck Pain and Disability Scale (NPAD) were utilized in this
study. A small effect size in pain reduction for trigger point injections was
reported as pain intensity at 1 to 2, 3 to 4, 7 to 8, 16, 18, and 24 weeks
follow-up. The effect size for trigger point injections was significant only
at the 3 to 4 weeks follow-up period (P=0.02). High heterogeneity was reported
among studies assessing the effect of local anesthetic injections, I2 =92%
(27 =82.67, P< 0.001). No serious adverse events were reported. This study
was limited by high study heterogeneity especially among local anesthetic
injection studies, response bias, variations in quantity and type of local
anesthetic used across studies and inclusion of various study designs with
various adjunct treatments given to participants.16

A 2019 systematic review and meta-analysis was performed to evaluate the
effectiveness of LA trigger point injections in adults with MPS in the head,
neck, and shoulder regions as compared to dry needling, placebo, and other
interventions. In total, 15 RCTs were included which was comprised of 884
adult patients. The local anesthetic group showed a significant improvement in
VAS pain scale (1.585 units) at 1 to 4 weeks follow up as compared to the dry
needling group (95% confidence interval -2.926 to -0.245; P = 0.020). However,
when only double-blinded studies were considered, the local anesthetic
resulted in an improvement of 1.478 VAS units (95% CI = -4.458 to 1.502) which
was not statistically significant (P = 0.331). Significant improvements in
pain of 0.767 units was reported in the local anesthetic group at 2 to 8 weeks
as compared to the placebo group (95% confidence interval -1.324 to -0.210; P
= 0.007). Limitations in this study include heterogeneity, high risk of bias
and a modest sample size. Most of the studies did not control for the use of
concurrent therapies, compliance with treatment prescribed and had high risk
of bias. Authors acknowledge the need for well-designed studies in the
future.17

A 2016 RCT was conducted to determine whether LA into trigger points combined
with a PT program would be more effective than each separate treatment alone
in improving pain, function, and quality of life in a group of patients with
MPS of the shoulder girdle and cervical region. Three groups comprised of 127
patients with shoulder girdle MPS for more than 6 weeks and pain greater than
40 mm on the visual analog scale (VAS) were assigned. The 3 intervention
groups were: PT, LI, or the combination of both (PT + LI). The final sample
was comprised of 135 patients resulting in 45 patients randomly allocated to
each of the 3 groups. No significant intergroup differences were reported in
VAS at 1 month PT + LI, 40.8 [25.3] vs. PT, 37.8 [21.9], p = 0.560 and vs. LI,
44.2 [24.9], p = 0.545. Secondary outcomes resulted in no differences between
groups except the PT and PT + LI groups had higher right upper limb hand-back
maneuver scores as compared to the LI alone group at both 1 and 3 months (p
=0.013 and p = 0.016 respectively). Limitations include short term follow up,
small sample size, and variation in intervention application.18

A 2015 prospective study was performed to investigate the efficacy of
lidocaine injection in the intramuscular innervation zone (IZ) for the
treatment of chronic neck pain caused by myofascial trigger points (MTrPs) in
the trapezius muscle. A total of 120 patients with myofascial pain syndrome
(MPS) of the trapezius muscle were randomly divided in 1 of 5 groups. The
first group (n=24) received saline (0.9% NaCl) injections at the MTrPs. The
second group (n=24) received 0.5% lidocaine injections at the MTrPs. The third
group (n=24) received saline (0.9% NaCl) injections at the mid-upper
trapezius. The fourth group (n=24) received 0.5% lidocaine injections at 2
separate points of the lower trapezius. Lidocaine injection treatments in the
intramuscular innervation zone yielded a significant reduction in the degree
and frequency of neck pain at 6 months as compared to the MTrp injection
group. Reductions were especially prevalent in the combined lidocaine
injection treatments in the IZ mid-upper trapezius, and the lower trapezius
are more effective (all P <0.05). Limitations include small sample size, study
design and short term follow up.19

A 2021 retrospective study was performed to evaluate and compare the
effectiveness of LA, botulinum toxin (BTX), and platelet-rich plasma (PRP)
injections for the treatment of myofascial TrPs in the masseter muscle.
Between 2016 and 2019 patients were included if they were treated with
myofascial TPIs in masseter muscle. Patients were divided into 1 of 3 groups:
Group 1 (LA injection), Group 2 (BTX injection), Group 3 (PRP injection). The
primary outcome was average pain at rest, while chewing and pressure pain
intensity (PPI), Jaw Functional Limitation Scale (JFLS) value. Secondary
outcomes included the quality-of-life (measured using Oral Health Impact
Profile-14 (OHIP-14)). Outcomes were assessed at diagnosis, and 1-, 3-, and
6-months post-treatment. A total of 82 patients were enrolled (Group 1 (n=27),
Group 2 (n=26), and Group 3 (n=29)). Improvements in all parameters were seen
in Group 1 and Group 2 as compared to Group 3 at 3 months follow up.
Significant results were seen in Group 2 as compared to Group 1 at 3 months
follow up in VAS pain, JFLS, and OHIP-14 (P = .009; P = .004; P = .002).
Significant improvements were seen in Group 2 in VAS pain, JFLS, and OHIP-14
(P = .008; P < .001; P < .01) at 6 month follow up. Limitations include lack
of control group, comorbidities were not considered, small sample size and
short follow up. Authors conclude that all procedures showed improvement in
symptoms of TrPs in the masseter muscle at 1 and 3 month follow up but note
that BTX injections resulted in superior results at 3 months follow up and
remained effective until 6 month follow up.20

**Headache**

Injection of botulism toxin for headache is not included as it is out of the
scope of this policy.

A 2022 systematic review aimed to evaluate percutaneous interventional
treatments for prevention of migraines. Both qualitative and quantitative
analysis methods were utilized. An expert panel was formed and evidence-based
recommendations for the preventative and interventional treatment of migraines
was developed. Clinical outcomes considered included headache days, acute
medication use, and functional impairment. A total of 16 randomized controlled
trials were included in qualitative synthesis and 2 articles were excluded
from quantitative synthesis because of inadequate outcomes reporting. With
regard to trigger point injections, the committee researched the following
clinical question, "Are TPIs with LA more effective than saline injections in
reducing headache days per month, acute medication use per month, and
impairment as defined by patient reported outcomes?" The committee found
insufficient evidence to assess trigger point injections in migraine
prevention. Support for the Migraine Prevention Project of the American
Academy of Pain Medicine Foundation (AAPMF) was received as unrestricted
grants from Amgen Inc., Lilly USA, LLC, Supernus Pharma, and Teva
Pharmaceuticals.21

A 2015 RCT comprised of 70 patients was conducted to examine the effect of
blocking trigger points in the temporal muscles of patients with masticatory
myofascial pain syndrome, fibromyalgia and headache. Patients with 1 trigger
point were randomly divided into 3 groups: injection with saline (n=26) or
anesthetic (n=21) and non-injected (control) (n=23). Ultimately, after lost to
follow up and exclusions, the patients analyzed for the 3 groups were:
injection with saline (n=14) or anesthetic (n=17) and non-injected (control)
(n=16). Both saline and anesthetic treatments significantly reduced the
intensity of facial pain, (p = 0.004 and p < 0.001) and showed a decrease in
headache frequency which were statistically significantly different (p = 0.037
and p = 0.002) and yielded effective results regarding headache intensity,
differing from the control group (p = 0.008 and p = 0.001). Limitations
included small sample size, short duration of follow up, and lost to follow
up. Authors conclude decreased facial pain and frequency and intensity of
headache resulted in treatment with trigger point injection treatments. Local
anesthetic and saline were effective whereas the control group was not
statistically significant.22

A 2013 randomized double-blind controlled study aimed to assess the efficacy,
safety, and tolerability of local lidocaine injections in the prophylaxis of
chronic tension-type headache (TTH). A total of 48 patients referred to
neurology clinics and diagnosed as chronic TTH were randomized into 1 of 2
groups: the 0.5% lidocaine injection (n=24) or 0.9 NaCl saline injection
(n=24) group. The inclusion criteria were headache for 15 days or more in a
month, between 18 and 65 years of age, chronic TTH with a history of at least
6 months since the beginning, and not responding to optimal doses of
antidepressants for at least 3 months. Evaluations and injections were
performed by separate physicians and the evaluator was blind to the treatment
group. There was no statistically significant difference between mean age and
distribution of male and female participants between groups (p = 0.937 and p =
1.000, respectively). When compared to the pretreatment values, the lidocaine
group demonstrated a statistically significant decrease in posttreatment after
the first month in number of painful days, number of analgesics tablets used,
VAS and Hamilton depression and anxiety scores (p<0.001). When comparing in
the placebo group, favorable therapeutic response rates were observed the
first month following treatment when considering the number of painful days
and number of analgesics used, VAS scores, and Hamilton depression and anxiety
scores (p < 0.001). No serious adverse events were reported. Authors conclude
lidocaine injection may be an effective treatment in patients with chronic TTH
that did not respond sufficiently to analgesics and antidepressants. This
study was limited by small sample size and short-term follow up.23

A 2011 retrospective review comprised of 147 consecutive patients aimed to
determine if a wider spectrum of cervically mediated symptoms exist, and to
investigate a potential role of greater occipital nerve blocks (GON) and
trigger point injections (TPI) in these patients. Chief complaints included:
dizziness (93%), tinnitus (4%), headache (3%), and ear discomfort (0.7%) while
general symptoms included: dizziness (97%), headache (88%), neck pain (63%),
tinnitus (23%), and ear discomfort (22%). A combination of betamethasone
sodium phosphate 6mg as 1mL and 0.25% bupivacaine hydrochloride as 2mL in a
syringe made the GON and TPI treatment. Results after GON/TPI treatments:
"neck range of motion (71%), headache (57%), neck pain (52%), ear discomfort
(47%), dizziness (46%), and tinnitus (30%). Dizziness responders had neck
position asymmetries (84%), reproducible dizziness by cervical and
suboccipital musculature vibration (75%), and pre-injection posterior vertex
sensory changes (60%)." Limitations included small sample size, study design,
and recall bias. Authors concluded a wider array of cervically mediated
symptoms may influence the "trigeminocervical and vestibular circuitry through
cervical afferent neuromodulation."24

A 2010 systematic review was conducted. PubMed was systematically searched for
literature addressing peripheral nerve blocks (PNBs) and trigger point
injections (TPIs) treatments for headaches. Authors report a paucity of data
on the efficacy of TPIs for headache disorders. Authors note the lack of
standardization of injection schedule for TPIs. Limitations include lack of
classifying headaches according to standardized criteria. A considerable
number of patients did not meet the current International Headache Society
criteria for CDH.25

A 2009 RCT comprised of 45 patients was conducted to compare the use of 2
different substances for trigger point injectate to dry-needling to alleviate
headache. Assessed outcomes included levels of pain intensity, frequency and
duration, local post-injection sensitivity, obtainment time and duration of
relief and the need to use analgesics to control headaches. A random draw
method was utilized to divide the patients into 3 groups: Group 1 (dry
needling), Group 2 (lidocaine at 0.25%), and Group 3 (botulinum toxin 25 or
50U). Outcome measures were obtained by employing the Symptom Severity Index
(SSI), Palpation of the trigger point and reproduction of the chief complaint
(headache), Pain diary, and Pain questionnaire. With the exception of rescue
medication and local post injection sensitivity, all treatment groups yielded
promising results (p0.05). Limitations include small sample size, short
follow up and recall bias. Authors conclude lidocaine may be considered as the
substance of choice while, for refractory cases, botulinum toxin may be the
best choice.26

**Anterior Cutaneous Nerve Entrapment**

A 2016 systematic review was conducted to outline the current available
literature concerning the treatment of patients diagnosed with Abdominal
Cutaneous Nerve Entrapment Syndrome (ACNES). A total of 7 studies were
included for analysis and were comprised of 381 patients that were undergoing
treatments using trigger point injections (TPI) or anterior neurectomy as a
standalone procedure, and TPI followed by anterior neurectomy refractory
ACNES. One study was a RCT27, 4 retrospective reviews and 2 case series.
Authors defined short-term success as "a >50% pain reduction using pain
intensity numerical rating scale and/or a minimal 2-point reduction using VNRS
at 1 to 3 months follow-up and long-term success was defined as "pain
intensity numerical rating scale scores <50% of preoperative pain levels or if
the present VNRS was at least 2 points lower". Short term success was found in
70% of patients, while long term success was reported in 61% of patients.
Following TPI treatment, a positive response was seen in 86% of patients and
73% still showed a positive response at a mean follow up of 32 months.
Successful treatment was reported in 50% of patients in 2 other studies. The
trial utilizing anterior neurectomy resulted in a successful pain response 73%
in the treatment group versus 18% in the sham group. Two cohort studies
yielded 69% patients satisfied at 18 months and 61% patients satisfied at 32
months follow up in the neurectomy groups.28 Limitations include small sample
size, varying study designs including retrospective, risk of selection bias, 3
studies from the same group, and different reporting methods for outcomes.

A 2013 RCT was conducted with the intent to clarify the role of local
anesthetic injection in diagnosing ACNES. The hypothesis was lidocaine
injection would yield a greater decrease in pain than that after saline
injection. A total of 48 patients with suspected ACNES were randomized to
receive 10ml 1% lidocaine (n=24) or saline injection (n=24). Injections were
made into the point of maximal abdominal wall pain just beneath the anterior
fascia of the rectus abdominis muscle. A visual analogue scale (VAS) and
verbal rating scale (VRS) were utilized just before the injection and 15-20
mins following injection. A successful response was defined as >50% reduction
of pain on the VAS and/or a reduction of 2 points on the VRS. Successful
responses occurred in 4 patients in the saline group compared to 13 patients
in the lidocaine group (P =0*007). No severe adverse events occurred. Authors
concluded entrapped branches of intercostal nerves may contribute to chronic
abdominal pain. A reduction of pain was seen in patients following local
infiltration which authors state was based on anesthetic mechanism rather than
mechanical effect or placebo effect. Limitations include small sample size, a
blinded experienced investigator was able to predict the type of injected
agent correctly in the majority (three-quarters) of patients.27

A 2012 RCT reported on 48 adult suspected ACNES who received in injection with
LA (n=24) or saline (n=24) into the point of maximum abdominal wall pain just
beneath the anterior fascia of the rectus abdominal muscle. Pain was measured
with the before and after injection and 50% reduction was considered
successful response which was significantly higher in the group receiving
lidocaine (13 of 24 versus 4 of 24 in saline group; P = 0*007). The authors
conclude that pain reduction after lidocaine infiltration may play a
diagnostic role for ACNES.27

A 2011 cohort study of 139 consecutive patients with chronic abdominal pain
suggestive of ACNES were assessed to evaluate the efficacy of a diagnostic
workup protocol and treatment regimen. This study was performed between
January 2003 and August 2008 in the Maxima Medical Center, Veldhoven, The
Netherlands. A visual analog reduction of at least 50% was seen in 81% (n=94)
after the first injection. After injection therapy alone, 33% (n=44) remained
pain-free permanently while 71% (n=49) of the neurectomy patients was
considered successful. Authors report a long-term efficacy was achieved in 71%
with a satisfying visual rating scale of 1-2 results, however the median
follow up was 18 months (range, 1-64 months). Attenuated levels of pain
(visual rating scale 3) were reported in 9%. Authors conclude consecutive
local TPIs is effective in 1/3 ACNES patients. Authors report surgical
neurectomy is effective in 2/3 of refractory patients. This paper provides
support for use of a single diagnostic TPI for diagnosis of ACNES.29
Limitations include recall bias, referral bias, small sample size, short
follow up, and study design.

**Low Back Pain**

A 2008 systematic review of randomized control trials to assess if injection
therapy is more effective than placebo or other treatments for patients with
subacute or chronic low back pain. This study was an update of a previous
systematic review and included searches of the Cochrane Central Register of
Controlled Trials, MEDLINE, and EMBASE databases. The search included RCTs
with effects of injection therapy involving epidural, facet, or local sites
for subacute or chronic low back pain publications up to March 2007. A total
of 18 trials (n=1179) were included. Ten of 18 studies were rated as high
quality. Due to the heterogeneity among studies, statistical pooling was not
performed. A variety of drugs were studied including local anesthetics,
corticosteroids, and a variety of other drugs. The studies were subdivided by
injection site, pharmaceutical agent and comparison of treatment. Authors
concluded that there was no strong evidence either for or against the use of
injection therapy of any type. They go further to state more research is
needed to identify a subgroup of patients that some type of injection would
benefit. Limitations included high heterogeneity among included studies,
variations in injections sites, and different drugs were utilized.30

A 2014 guideline update was published by AANS/CNS Joint Guidelines Committee
focusing on injection therapies, low-back pain and lumbar fusion based on
evidence. Lumbar TPIs (Grade B) "performed as dry needling, with anesthetics
alone or with steroids, are not recommended in patients with chronic low-back
pain without radiculopathy from degenerative disease of the lumbar spine
because a long-lasting benefit has not been demonstrated (Level II evidence)."
Authors state "there is insufficient evidence to support or refute the use of
trigger point injections for chronic lower back pain without radiculopathy."31

A 2011 randomized trial was performed to compare the effects of trigger point
(TRP) mesotherapy and acupuncture (ACP) mesotherapy in the treatment of
patients with chronic low back pain. A total of 62 subjects were recruited
between July 2006 and May 2008 at outpatients Physical Medicine and
Rehabilitation Clinic at the University of Rome. Patients were randomized to
receive 4 week treatments with either trigger point mesotherapy (n = 29) or
acupoints mesotherapy (n = 33). Outcomes were measured utilizing the visual
analogic scale (VAS), McGill Pain Questionnaire Short Form (SFMPQ), Roland
Morris Disability Questionnaire (RMQ) and Oswestry Low Back Pain Disability
Questionnaire (ODQ). Mean values at baseline were performed and a comparative
analysis was completed at the end of the treatment (after 4 weeks) and follow-
up (12 weeks from the last treatment). A statistically significant difference
was seen for ACP over TRP in SF-MPQ measures over time (p = .035). Patients
reported slight neck pain (15%) in the ACP group between the first and second
sessions. Authors conclude their results "suggest that the response to ACP
mesotherapy may be greater than the response to TRP mesotherapy in the short
term follow-up (12 weeks after the end of last treatment) and show that the
stimulation site is important." Authors go on to acknowledge that more studies
with robust design are needed to evaluate the efficacy and safety of
mesotherapy and especially as it pertains to musculoskeletal pain management.
Limitations include small sample size, short follow up, response bias, and
sample bias.32

A 2019 randomized study comparing intravenously administered non-steroidal
anti-inflammatory drug (NSAID) and TPI in the treatment of low back pain (LBP)
patients admitted to the emergency department due to pain caused by trigger
points. Patients were randomized into the NSAID (group 1, n=32) or TPI (group
2, n=22). The TPI group showed a significant decrease in pain scores. A mean
VAS decreased by 0.41  1.30 in the TPI group and by 2.59  2.37 in the NSAID
group (p < 0.001) after the 60 min follow up period. Authors conclude results
showed TPI was superior to intravenous NSAIDs in the treatment of LBP.
Limitations include small sample size, study method, and short follow up of
only 60 mins.33

A 2014 prospective study was performed to determine the prevalence of active
trigger points accompanying lumbosacral radiculopathy and to evaluate the
effect of trigger point injection on patient's pain scores and straight leg
raise (SLR). A total of 98 patients were enrolled. All patients were referred
to an orthopedic clinic for lumbosacral radiculopathy. Baseline examination
included history and physical, labs, radiology services, and pain severity.
VAS and SLR were utilized. A positive SLR was defined as patients feel pain
during 0 to 70 degrees of leg raising. A negative SLR was defined as no pain
was experienced during leg raising. Disc disease was confirmed by MRI and
lumbosacral x-ray. An oral dose of Diclofenac Na (25mg) was given 4 times a
day to each patient The presence of trigger points and degree of pain was
evaluated after a week. Patients who did not have trigger point pain were
excluded from the study and patients who did were divided into 2 groups, TP
(n=32, TP injections, 1ml lidocaine 2%) and N (n=32, former conservative
therapy). "Pain scores (Mean  SD) in TP group was 7.12  1.13 and in N group
was 6.7  1.16, P = 0.196. Following the treatment, pain scores were 2.4  1.5
in TP group and 4.06  1.76 in N group P = 0.008. SLR test became negative in
all patients in TP group but only in 6 (19%) patients in N group, P = 0.001."
Authors conclude that trigger point injection can significantly improve
recovery in patients with chronic lumbosacral radiculopathy.34

A 2022 RCT compared effectiveness of gluteal trigger point injections to
epidural steroid injection for lumbosacral canal stenosis in 44 patients. Pain
was measured at baseline, 2 weeks and 8 weeks and the authors report both
groups had a decrease in pain however the trigger point group had more
sustained relief than the epidural group at weeks 2, 4 and 8. (p<0.001
p=0.008, and p<0.001, respectively).35 Limitations include lack of blinding,
lack of control, short term follow up and small sample size.

Up To Date addresses trigger points in "Subacute and chronic low back pain
nonsurgical interventional treatment".36 They stated a systematic review30
found no clear difference between local or trigger point injections with local
anesthetic, with or without corticosteroids, and control interventions such as
saline, dry needling or ethyl chloride plus acupressure, for short short-term
pain relief in 3. trials of patients with sub-acute or chronic low back pain.
The trials were criticized for methodological shortcomings and high level of
heterogeneity and did not support widespread use. The author state TPI may be
beneficial in patients with tender points associated with myofascial pain
syndrome.

**Whiplash**

A 2013 systematic review did not find benefit of botulinum toxin-A compared to
saline for management of whiplash or other injectants reviewed including LA,
steroids and saline.37

A 2009 controlled case series reports on 17 patients with chronic neck pain
following whiplash who received TPI with anesthetic in the upper trapezius and
compared it to 10 controls who received anesthetic injection into the thigh.
The authors reported immediate improvement in cervical range of motion and
pain following an average of 3.8 injections into the identified trigger points
with an increased range of motion ranging from 27-49%.38 Limitations include
lack of blinding, small sample size, variable in number of injections/dosing
and short-term follow-up.

**Neck Pain**

Literature search did not find any articles that addressed the role of trigger
point injections for non-radicular neck pain. Myofascial pain syndrome in the
neck is addressed above.

A systematic review was conducted, and strength of evidence measured with
**Grading of Recommendations Assessment, Development and Evaluation** (GRADE)
methodology. GRADE analysis for intramuscular lidocaine with stretch for
chronic myofascial pain was rated Very Low, for chronic non-specific
mechanical neck pain vs. dry needling was rated Low, and steroid injection
(with or without LA) for chronic neck pain with radiculopathy and radiation
was rated Low.37

**Fibromyalgia**

Prior to 2010 tender points were part of the diagnostic criteria for
fibromyalgia. SMEs discussed the differences between tender points and trigger
points. The main difference is the presences of a taut band and referral
pattern associated with trigger point and absent in tender point. It is
possible for both to occur in the same patient. Most papers in literature
search were case reports or review articles.

A 2014 RCT included 60 female subjects divided into three groups. One group
received lidocaine only, saline only lidocaine and saline injections into the
trapezius and gluteal muscles. The authors reported a decrease in hyperalgesia
more after lidocaine than saline (p=.004), but both lead to improvements.39
Limitations of this study included insufficient sample size to draw
conclusions and lack of placebo control group.

A prospective study evaluated patients with myofascial pain syndrome caused by
active trigger points with (n=9) and without fibromyalgia (n=9) who received
TPI into upper trapezium muscle. Pain intensity, threshold and range of motion
was measured before, immediately after and 2 weeks after TPI reported.
Significant improvement in range of motion in both groups after TPI was
reported.40 Sample size was too small for reliable conclusion.

A 2004 systematic review focused on optimal management of fibromyalgia
syndrome included trigger point injections as a treatment option. At the time
of this review there were no RCT and a few uncontrolled articles for TPI for
fibromyalgia. The authors conclude no evidence for trigger point injections in
this review.41

**Non-Malignant Musculoskeletal Pain**

A 2009 systematic review of 15 studies was conducted to assess the evidence on
the efficacy and safety of using trigger point injection (TPI) to treat
patients with chronic non-malignant musculoskeletal pain that had persisted
for at least 3 months. Ten trials assessed TPI in patients with head, neck,
shoulder, and/or back pain. The authors report that these studies were limited
by small sample size, high heterogeneity, and reporting bias. the authors
conclude "no clear evidence of either benefit or ineffectiveness". They state
that the procedure is safe when performed by appropriately trained providers
and can aid in symptom relief regardless of injectant used and maybe a useful
adjunctive therapy.42

**Complex Regional Pain Syndrome**

Complex regional pain syndrome is a condition characterized by pain that is
disproportionate to the extent and duration of the primary injury and extends
beyond the specific peripheral nerve involved. Literature on the role of TPI
in management of complex regional pain syndrome is limited to case reports,
case series, and reports with very small sample sizes.

**Sexual Dysfunction/Pelvic Pain**

The role of TPI for sexual dysfunction and pelvic pain is limited to case
reports and small pilot studies. A 2014 pilot study reported on 29 women (17
with PT and 12 with TPI) with pelvic floor dysfunction. Both groups reported
reduction in vaginal pain from baseline.43 Limitations include small sample
size, variation in treatment duration, number of interventions, and lack of
controls.  
  
A 2022 retrospective longitudinal study reported on 186 women with chronic
pelvic pain treated with ultrasound guided peripheral nerve blocks and trigger
point injections to pelvic floor muscles in conjunction with pelvic floor
physical therapy once weekly for 6 weeks. Pain was measured using visual
analog scale and functional pelvic pain scale. They report statistically
significant improvement in pain after treatment.44 Limitations include no
comparison to PT alone which is known to provide benefit in chronic pelvic
pain, short term follow up and retrospective study design.

**Hemiplegic Shoulder Pain**

A 2012 RCT of 24 patients with hemiplegic shoulder pain randomized 12 patients
to standard therapy and 12 received segmental neuromyotherapy. This involved
injection of local anesthetic into the taut band and trigger points using a
needle which is same technique as trigger point injections. The authors report
improvement in pain scores before and after the injections in the treatment
group.45 The study is limited by lack of blinding, small sample size and short
term follow up.

A 2021 systematic review and meta-analysis included 1 randomized control
trial.45 While meta-analysis was conducted since there was only 1 trial with 9
patients that addressed this population that result is inconclusive.

**Neuropathic Pain**

A 2019 prospective study evaluated the effect of a piriformis trigger point
injection on neuropathic pain in 30 patients with piriformis syndrome. All
patients received a trigger point injection under ultrasound guidance into the
piriformis muscle with local anesthetic and steroid. Pain assessments before
and after the injection reported statistically significant improvement
(p<0.001) for all scores at 1 week and 1 month compared to baseline values
with the greatest improvement at the first week post injection. The authors
conclude that the pyriformis injection is effective for both somatic and
neuropathic pain in pyriformis syndrome patients.46 The study is limited by
lack of randomization and control, and small sample size.

**Societal Guidance**

  * A 2010 guideline by the American Society of Anesthesiologists produced practice guidelines for chronic pain management. Authors concluded the literature is "insufficient to evaluate the efficacy of trigger point injections (i.e., compared with sham trigger point injection) as a technique for providing pain relief for patients with chronic pain (Category D evidence)". Studies with observational findings suggest that trigger point injections may provide relief for patients with myofascial pain for assessment periods ranging from 1 to 4 months (Category B2 evidence). Consultants, ASA members, and ASRA members agree that trigger point injections should be used for patients with myofascial pain. Recommendations for trigger point injections. Authors go further to state trigger point injections may be considered for treatment of patients with myofascial pain as part of a multimodal approach to pain management.47,48
  * American Association of Neurological Surgeons (AANS)/Congress of Neurological Surgeons guidelines state there is insufficient evidence to support or refute the use of trigger point injections for chronic lower back pain without radiculopathy because long-lasting benefit has not been established (Level II evidence).31
  * American College of Occupational And environmental Medicine (ACOEM)17 review concludes trigger and/or tender point injections are Not Recommended with Moderate Confidence for treatment of acute back pain. Trigger and/or tender point injections may be Recommended (C) Low Confidence as a reasonable second or tertiary option for the treatment of subacute or chronic low back pain that is not resolving with conservative measures. They state that the injectant should contain topical anesthetic or dry needle laying without an injection repeat injection should be based on improvements. They should be in conjunction with an active program and recommend 3 to 4 weeks between injections. They state if a first set of injections is not satisfactory a second set is reasonable but if improvement after that point is not achieved further injections is not recommended. The use of glucocorticosteroids is Not Recommended (C) Moderate Confidence for use in TPI.
  * North American Spine Society50

Interventional Question 13. In patients with low back pain, do trigger point
injections decrease the duration of pain, decrease the intensity of pain,
increase the functional outcomes of treatment and improve the return-to-work
rate?

There is insufficient evidence to make a recommendation for or against the use
of trigger point injections in the treatment of low back pain. The type of
injectate does not influence outcomes.  
Grade of Recommendation: I

  * American Society of Interventional Pain Physicians (ASIPP) Practice Guideline, Interventional Techniques in the Management of Chronic Pain, Part 2.0 they review 7 RCTs and conclude Level III-IV strength of evidence in addition to "overwhelming support from respected authorities".1 The paper also highlights the challenges in diagnosis of trigger points and if the pain is from other sources. The authors divide the injections into diagnostic/stabilization phase and therapeutic phase. In the diagnostic phase they state injections should be at least 1 week apart and not exceed 4 in 1 year. In therapeutic phase injections should be at least 2 months apart with >50% improvement lasting at least 6 weeks and not exceed 6 in a year.

Trigger point injections have been described as an overall safe and effective
modality for the treatment of pain associated with myofascial trigger points.
There is moderate evidence to support a role of trigger point injections for
myofascial pain related to the presence of a trigger point. Nonetheless, there
are no high quality randomized controlled trials or large observational
studies to support this and most studies that have investigated TPI are not
blinded, lack controls, standardized patient selection and assessment of
improvement, small sample sizes and lack of long-term follow-up.

Evidence suggests that early conservative measures, such as physical therapy,
may prevent the need for injections. Therefore, TPI are covered for refractory
pain associated with trigger points that do not respond to conservative
therapy or in patients with significant limitations in mobility that can be
improved by the trigger point while undergoing conservative treatment.
Additionally, a single diagnostic trigger point can play a role in diagnosis
for myofascial pain an ACNEs. There is evidence to support a role for
treatment of headache if associated with the presences of a trigger point. The
frequency of trigger point injections is not well established in the
literature, but most experts agree that the benefit should last at least 4
weeks and typically several months. There is a paucity of evidence on long
term use of TPI and most literature is limited to 2 to 8 weeks. Use of TPI
beyond six months is not supported in current literature.

The use of TPI for other conditions including non-specific low back pain
(LBP), complex regional pain syndrome, widespread diffuse pain, chronic pain
syndrome, fibromyalgia, pelvic floor myalgia, hemiplegic shoulder pain,
lumbosacral canal stenosis, whiplash, non-malignant musculoskeletal pain, and
neuropathic pain is not supported by evidence and therefore considered
investigational.

There are some emerging studies that help define the ultrasound
characteristics associated with trigger points and also explore a role of
ultrasound guidance for TPIs. However, there is not a clear standard for
characterization of the trigger points and adjacent soft tissue by ultrasound.
There is a paucity of evidence that ultrasound improve effectiveness of TPIs
and a lack of evidence that it improves safety, therefore its use is
considered investigational.