Frederick P.Whiddon College of Medicine, University of South Alabama, Mobile, AL 36688, USAUnited States
Department of Emergency Medicine, University of South Alabama, 307 N University Blvd, Mobile, AL 36688, USAUnited States
University of South Alabama Health University Hospital, Mobile, AL 36617, USAUnited States
Also available as PDF (figures and tables appear in the PDF).
Objectives Earlier literature provided evidence of neck pain relief via cervical trigger point injections with anesthetic agents. However, recent evidence suggests that intramuscular or paraspinal cervical injections with local anesthetic may provide relief for various types of headaches and orofacial pain as well. The primary purpose of this systematic review was to determine whether a cohort of retrospective case studies and randomized controlled trials using paraspinal cervical or intramuscular anesthetic injections were associated with a decrease in headache and orofacial pain. Methods A systematic review of the literature was performed to observe the association between headache or orofacial pain relief and paraspinal cervical injections with various pain-relieving agents. Literature searches using the key terms “headaches”, “paraspinous cervical injections”, “neck/intramuscular injections” and “orofacial pain” were performed in PubMed, Google Scholar, and Scopus. We implemented the preferred reporting items for systematic reviews and meta-analyses (PRISMA) format for the systematic review. Results Initially, four hundred forty articles were located during the systematic review. Five total articles were selected for review and 435 were excluded because they did not meet search criteria. Another two relevant articles were found during manual searches within references of the systematic review. The seven studies included were retrospective case studies involving patients with headaches or orofacial pain who received paraspinal cervical or other intramuscular injections. A total of 841 patients’ data were tallied from the 7 articles and 683 of those patients received anesthetic injections. Significant pain relief due to intramuscular or paraspinal cervical injections was observed in 83.7% of the patients. Conclusion Our systematic review of association between headache or orofacial pain relief and paraspinal cervical injections with various pain-relieving agents demonstrated a frequency of headache and orofacial pain relief of 83.7%. Such a large percentage compared to a robust placebo study provides promising evidence that this treatment may have a therapeutic role in the management of headache and orofacial pain. Despite limitations faced in performing our systematic review, it seems quite clear that pain relief for these headache patients can be attributed to intramuscular anesthetic or dry needling injections. While larger prospective studies should be performed regarding specific location and anesthetic, our systematic review provides additional evidence that anesthetic intramuscular and dry needling injections provide pain relief intension-type headaches (TTH), migraine headaches, cervicogenic headache pain, and orofacial pain.
Keywords: Headache; Cervical injections; Orofacial pain; Dry needling; Saline injections; Paraspinous injections
A systematic review of the literature was performed to observe
paraspinal cervical injections with various pain-relieving agents. Literature searches using the key terms “headaches”, “paraspinous
cervical injections”, “neck/intramuscular injections” and “orofacial pain”
implemented the preferred reporting items for systematic reviews and meta-analyses (PRISMA) format for the systematic review.
Initially, four hundred forty articles were located during the systematic review. Five total articles were selected for review and 435
were excluded because they did not meet search criteria. Another
references of the systematic review. The seven studies included were retrospective case studies involving patients with headaches
or orofacial pain who received paraspinal cervical or other intramuscular injections. A total of 841 patients’ data were tallied from
the 7 articles and 683 of those patients received anesthetic injections. Significant pain relief due to intramuscular or paraspinal
cervical injections was observed in 83.7% of the patients.
Our systematic review of association between headache or orofacial pain relief and paraspinal cervical injections with various
pain-relieving agents demonstrated a frequency of headache and orofacial pain relief of 83.7%. Such a large percentage compared
to a robust placebo study provides promising evidence that this treatment may have a therapeutic role in the management of
headache and orofacial pain. Despite limitations faced in performing our systematic review, it seems quite clear that pain relief for
these headache patients can be attributed to intramuscular anesthetic or dry needling injections. While larger prospective studies
should be performed regarding specific location and anesthetic, our systematic review provides additional evidence that anesthetic
intramuscular and dry needling injections provide pain relief intension-type headaches (TTH), migraine headaches, cervicogenic
headache pain, and orofacial pain.
Headache; Cervical injections; Orofacial pain; Dry needling; Saline injections; Paraspinous injections.
Copyright 2023 by Butler D. This is an open-access article distributed under Creative Commons Attribution 4.0 International License (CC-BY 4.0) the association between headache or orofacial pain relief and
were performed in PubMed, Google Scholar, and Scopus. We
two relevant articles were found during manual searches within
eadaches are one of the most common patient complaints
in medicine and on their basis of origin and character oc-
H
cur in a variety of categories. The International Classification of
Headache Disorders (IDCH) has 14 different classes of headaches,
with 4 being categorized as primary conditions and 10 falling under
secondary headaches.1 Specifically, a high prevalence of migraine,
cervicogenic, and tension-type headaches (TTH) have been attrib-
uted to tightening of specific myofascial areas known as trigger
2,3 points.2,3 Due to their high prevalence and clinical importance, it
is important to determine effective and efficient therapeutic inter-
ventions to reduce trigger point associated headaches. In recent
years, clinical trials and case studies have suggested paraspinal and
intramuscular injection with a variety of anesthetics may reduce
2,4
a spectrum of headache pains.2,4 However, no extensive system-
atic review has been performed to compare the various myofascial
injection procedures and medications used as treatment for the
varying headache classes and myofascial disorders of the head. We
performed a systematic review of the literature to determine the
frequency of reported pain relief after pericranial intramuscular or
paraspinal cervical injections, and to decipher if the specific pro-
cedure performed (i.e., dry needle, saline or anesthetic injection),
and specific anesthetic drugs used for treatment demonstrated any
difference in effectiveness.
Literature searches using the key terms “headaches”, “paraspinous/
cervical injections”, “neck/intramuscular injections”, “myofascial injections”,
“pericranial injections”, “trigger point injections”, “lidocaine”, “bupivacaine”,
“myofascial pain syndrome”, “anesthetic injections” and “oral/facial pain”
were performed in PubMed, Google Scholar, and Scopus. We
implemented the preferred reporting items for systematic reviews
and meta-analyses (PRISMA) format for the systematic review. We
screened articles for final review using the Rayyan Systematic Re-
view Software. In addition, we also reviewed any relating articles
within the references of those we included to maximize search
efforts (Figure 1).
Inclusion criteria were English language case series of patients over
18-years of age presenting to the clinic with a primary headache or
myofascial orofacial pain who were administered local anesthetic
paraspinal, intramuscular, pericranial, or myofascial injections for
treatment. Exclusion criteria were studies that included pediatrics,
administered nerve blocks, intravenous (IV)/catheter anesthetics,
or any other form of administration besides injections for treat-
ment of headache or orofacial pain. In addition, articles were ex-
cluded if the drug used was not local anesthesia (e.g., monoclonal
antibody), if other therapy was used in addition to injection, or
if the population was suffering from pain besides headache. The
articles were reviewed independently by one junior author and two
senior authors.
The systematic review originally located four hundred forty articles
based on our search terms. Sixteen articles were selected for
review of which eleven were excluded due to a variety of reasons
including patient age, injection site, and medication administered.
Two additional articles were found in a manual review of paper
references. A total of 7 articles matched our search criteria for the
systematic review.
The articles located in the review were retrospective cohort or pro-
spective case control studies that compared self-reported pain re-
lief with a variety of anesthetic injections in patients with migraine,
TTH, or generalized cervicogenic headache pain.4-10 A total of 841
patients with headache pain were reported in the 7 studies with
683 receiving anesthetic injections. Other patients either received
dry needling therapy or saline injections in the same trigger point
4-10
locations.4-10
Results of the studies reporting pain relief in the included
headache patients are shown in Table 1. Overall, 61.3% (419/683)
of patients who received a trigger point or cervical intramuscu-
lar injection of lidocaine, bupivacaine, or ropivacaine noticed full
4-10
pain relief shortly after injection.4-10 In addition, another 22.4%
of patients experienced partial relief with anesthetic injections in
the same location; thus, 83.7% of patients who received anesthetic
injections for TTH, migraine, or cervicogenic headaches reported
relief shortly after treatment. In comparison, only 37% of patients
with the exact same symptoms who received saline injections in the
same intramuscular locations saw relief after treatment, showing
significantly less pain relief than those who received anesthetics
(p=0.0061). Additionally, 93% of the 44 patients who received dry
needling in the studies for similar symptoms saw relief. There was
no association between the number of injection points and relief
reports for patients. While lidocaine was the most common choice
of anesthetic in our included studies (4 of 7 studies), ropivacaine
and bupivacaine were used in the larger studies with the greatest
numbers of patients (85%). Nevertheless, reported pain relief was
similar and there were no statistically significant differences be-
tween anesthetic type and pain relief when calculated with analysis
of variance (ANOVA) analysis (p=0.129).
The goal of our systematic review was to determine the frequency
of reported TTH, migraine, and cervicogenic headache relief af-
ter administration of intramuscular cervical or myofascial trigger
point anesthetic injections. In the study by de Craen et al11 the re-
ported placebo effect of injections on migraine relief was 32.4%.
In our systematic review complete or partial headache and orofacial pain relief was 83.7% for those receiving anesthetic injections.
Additionally, the comparison between placebo groups receiving
saline trigger point injections with those receiving anesthetic injec-
tions also reveals the effectiveness of such methods in reported
relief of headache patients.
Even though lidocaine was used most often, there did not
seem to be a distinguishable difference in effectiveness between
anesthetic type. This result, combined with the lower relief report-
ed with placebo saline trials, suggests that such intramuscular injec-
tions with anesthetics provide relief due to their common effect
5,12 in sodium channels of neurons to prevent depolarization.5,12 In all
studies, no other form of pain relief was administered during trial
which appears to further strengthen evidence of an association be-
tween anesthetic intramuscular injections and headache relief. The
specific mechanism regarding bupivacaine in headache relief is yet
to be determined, but evidence suggests an antinociceptive effect
on the trigeminocervical complex may be part of the pathway in
13-15
addition to reduction of the second order neuron cell activity.
Both the cervical and trigeminal afferents are known to converge
at the brainstem, and the periaqueductal gray (PAG), nucleus raphe 4-10
magnus, and the rostroventral medulla also synapse the trigemino-
cervical complex, providing a strong antinociceptive effect. This
16-19
complex may serve as the drug target. However, further investi-
gations are needed to to determine the exact mechanism of action
in such pain relief.
The most prevalent limitation in the studies found in our systemat-
ic review was the lack of follow-up after the trial to determine how
long anesthetic treatment was truly effective. In addition, these
were retrospective studies and relied upon patient reporting which
can be subjective and vulnerable to variability as it is challenging
to create a standard basis of relief. Most studies reported using
lidocaine as the anesthetic of choice, while the largest retrospective
studies used bupivacaine. This did not provide as wide a variety
of differences between anesthetics and relief as we had hoped to
compare initially in our review.
The retrospective reviews included in this systematic re-
view did not all report a placebo group. Thus, an effective placebo
effect could not be reported in our study. However, a 22 trial meta-
analysis regarding placebo effect in headache treatment published
in 2000 showed that after two-hours 25.7% of the oral placebo
patients self-reported no or mild headache severity compared to
32.4% of those receiving subcutaneous placebo.
Lastly, there was also some variability between studies re-
garding injection point sites. While all studies either implemented
pericranial trigger point or paraspinous cervical intramuscular in-
jections, the number of injections and exact location changed de-
pending on the study and headache location. This study assumes
that regardless of the muscle groups injected on the head or neck
the pain relief mechanism is the same, and it is likely that the same
central nervous system pain relief mechanisms are occurring in
both pericranial and paraspinous muscular injections.
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e e e e
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et he 01e ii tR 0 il 16 0 7 4 0
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714 74 411 801 85
ş h c t a e k ek k a 01 n e í a c t c g 4 8 9 5 d â e cr v ill l a l ill l l n a u n a i e a b a e a r a o t a t t a t
M e S e M e K e H
Despite such limitations, our systematic review demonstrated a re-
ported frequency of headache and orofacial pain relief of 83.7%.
Such a large percentage compared to a robust placebo study pro-
vides promising evidence that this treatment may have a therapeu-
tic role in the management of headache pain. While more studies
should be performed regarding specific location and anesthetic,
our systematic review provides additional evidence that anesthetic
intramuscular and dry needling injections provide pain relief in
TTH, migraines, cervicogenic headache pain, and orofacial pain.
The authors declare that they have no conflicts of interest.