4
Department of Veterans Affairs
Health Services Research & Development Service
Evidence-based Synthesis Program
Evidence Brief: Effectiveness of
Stellate Ganglion Block for
Treatment of Posttraumatic
Stress Disorder (PTSD)
February 2017
Prepared for:
Department of Veterans Affairs
Veterans Health Administration
Quality Enhancement Research Initiative
Health Services Research & Development Service
Washington, DC 20420
Prepared by:
Evidence-based Synthesis Program (ESP)
Coordinating Center
Portland VA Health Care System
Portland, OR
Mark Helfand, MD, MPH, MS, Director
Investigators:
Kim Peterson, MS
Donald Bourne, BS
Johanna Anderson, MPH
Katherine Mackey, MD
Mark Helfand, MD, MS, MPH
Evidence Brief: Stellate Ganglion Block for PTSD Evidence-based Synthesis Program
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PREFACE
The VA Evidence-based Synthesis Program (ESP) was established in 2007 to provide timely and
accurate syntheses of targeted healthcare topics of particular importance to clinicians, managers, and
policymakers as they work to improve the health and healthcare of Veterans. QUERI provides funding
for four ESP Centers, and each Center has an active University affiliation. Center Directors are
recognized leaders in the field of evidence synthesis with close ties to the AHRQ Evidence-based
Practice Centers. The ESP is governed by a Steering Committee comprised of participants from VHA
Policy, Program, and Operations Offices, VISN leadership, field-based investigators, and others as
designated appropriate by QUERI/HSR&D.
The ESP Centers generate evidence syntheses on important clinical practice topics. These reports help:
· Develop clinical policies informed by evidence;
· Implement effective services to improve patient outcomes and to support VA clinical practice
guidelines and performance measures; and
· Set the direction for future research to address gaps in clinical knowledge.
The ESP disseminates these reports throughout VA and in the published literature; some evidence
syntheses have informed the clinical guidelines of large professional organizations.
The ESP Coordinating Center (ESP CC), located in Portland, Oregon, was created in 2009 to expand the
capacity of QUERI/HSR&D and is charged with oversight of national ESP program operations, program
development and evaluation, and dissemination efforts. The ESP CC establishes standard operating
procedures for the production of evidence synthesis reports; facilitates a national topic nomination,
prioritization, and selection process; manages the research portfolio of each Center; facilitates editorial
review processes; ensures methodological consistency and quality of products; produces “rapid response
evidence briefs” at the request of VHA senior leadership; collaborates with HSR&D Center for
Information Dissemination and Education Resources (CIDER) to develop a national dissemination
strategy for all ESP products; and interfaces with stakeholders to effectively engage the program.
Comments on this evidence report are welcome and can be sent to Nicole Floyd, ESP CC Program
Manager, at Nicole.Floyd@va.gov.
Recommended citation: Peterson K, Bourne D, Anderson J, Mackey K, Helfand M. Evidence Brief:
Effectiveness of Stellate Ganglion Block for Treatment of Posttraumatic Stress Disorder. VA ESP
Project #09-199; 2017.
This report is based on research conducted by the Evidence-based Synthesis Program (ESP) Coordinating
Center located at the Portland VA Health Care System, Portland, OR, funded by the Department of Veterans
Affairs, Veterans Health Administration, Office of Research and Development, Quality Enhancement Research
Initiative. The findings and conclusions in this document are those of the author(s) who are responsible for its
contents; the findings and conclusions do not necessarily represent the views of the Department of Veterans
Affairs or the United States government. Therefore, no statement in this article should be construed as an official
position of the Department of Veterans Affairs. No investigators have any affiliations or financial involvement (eg,
employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received
or pending, or royalties) that conflict with material presented in the report.
Evidence Brief: Stellate Ganglion Block for PTSD Evidence-based Synthesis Program
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TABLE OF CONTENTS
Introduction ..................................................................................................................................... 3
Purpose ......................................................................................................................................... 3
Background .................................................................................................................................. 3
Methods........................................................................................................................................... 6
Results ............................................................................................................................................. 8
Literature Flow............................................................................................................................. 8
To What Extent Does SGB Provide Clinically Relevant Benefits for PTSD? ............................ 8
What are SGBs Potential Harms? .............................................................................................. 10
Who is Most Likely to Benefit? ................................................................................................. 11
Summary and Discussion .............................................................................................................. 11
Limitations ................................................................................................................................. 11
Clinical and Research Implications ........................................................................................... 12
Conclusions ................................................................................................................................... 14
References ..................................................................................................................................... 15
FIGURES AND TABLES
Figure 1: Literature Flowchart ........................................................................................................ 8
Table 1. Mean Change from Baseline for SGB versus Sham ....................................................... 10
Evidence Brief: Stellate Ganglion Block for PTSD Evidence-based Synthesis Program
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Background
The ESP Coordinating
Center (ESP CC) is
responding to a request
from Office of
Community
Engagement’s (OCE)
Center for
Compassionate
Innovation (CCI) for an
evidence brief on the
effectiveness of stellate
ganglion block (SGB)
for treatment of
posttraumatic stress
disorder (PTSD).
Findings from this
evidence brief will be
used to inform Subject
Matter Experts’
consideration of clinical
use and research and
program prioritization of
SGB for PTSD in the
VA.
Methods
To identify studies, we
searched MEDLINE®,
CINAHL, and more,
through December 2016.
We used prespecified
criteria for study
selection, data
abstraction, and rating
internal validity, and
strength of the evidence.
See our PROSPERO
protocol for our full
methods.
EXECUTIVE SUMMARY
Posttraumatic stress disorder (PTSD) is the third most common
psychiatric diagnosis among Veterans seen in the Veterans Health
Administration (VHA). PTSD can be debilitating, leading to a decline
in quality of life (QoL) and causing significant medical, mental health,
interpersonal, and social impairment. First-line treatments for PTSD
include psychotherapy, pharmacotherapy, or their combination;
however, several challenges have been identified in their effectiveness
and reach. Stellate ganglion block (SGB), also called cervical
sympathetic block, has been promoted as an adjuvant in individuals
with PTSD who have not fully responded to conventional therapies.
One proposed mechanism of action is that SGB might inhibit
connections between the peripheral sympathetic nerve system and
regions of the cerebral cortex thought to be abnormally activated in
PTSD. Some proposed benefits of SGB for PTSD include (1) it may
destigmatize treatment by offering a biologic approach to PTSD
management, (2) it may offer a fast-acting treatment alternative with
improvements reported within minutes to days of the procedure, and
(3) it may increase compliance as it does not require continuous daily
or weekly administration.
Our objectives were (1) to determine to what extent SGB provides
clinically relevant benefits for patients with PTSD, (2) to determine
SGB’s potential harms, and (3) to identify Veterans who are most
likely to benefit from SGB.
In uncontrolled, unblinded, retrospective case series, SGB for PTSD
had high rates of rapid clinical improvement in PTSD symptoms (70%
to 75%). However, findings from the first randomized trial (RCT) of
SGB for PTSD were inconclusive, neither confirming nor refuting
findings from case series. In the RCT, the range of mean percent PTSD
improvement after one round of SGB was 5.4% to 14.7%, and was
12.1% to 21.2% after the second round, which was no better than an
injection of saline. However, certain population characteristics and
intervention and comparator techniques used in the RCT were
suboptimal for determining efficacy and it was too small to estimate rates of serious
complications. The majority of study participants were active-duty military personnel with
unknown psychological and medical comorbidities and previous conventional therapy trials.
The pattern of very encouraging results in a few case series, followed by a negative RCT, is quite
common. The pattern suggests that, while it is possible that some patients benefit, the response
rates seen in case series will not hold up in actual practice. Substantial uncertainty remains about
the potential harms of SGB as well. The RCT, as well as RCTs of SGB for complex regional
pain syndrome (CRPS), were inadequately powered to support or refute findings from the
frequently cited, but methodologically weak, 1992 German questionnaire survey of 45,000 SGBs
that found 1.7 instances of severe complications per every 1000 individuals.
Evidence Brief: Stellate Ganglion Block for PTSD Evidence-based Synthesis Program
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Evidence was also insufficient to determine which Veterans are most likely to benefit from SGB
for PTSD. Clinical factors that could be used to select patients include failure to respond to, or
high risk of noncompliance with, conventional therapies, low risk of bleeding and other
complications, patient preference, and availability of SGB.
To determine whether some patients benefit, and which Veterans are most likely to benefit, new
RCTs designed to correct the deficiencies of the first trial should be conducted. These trials, as
well as a registry that adheres to methodological standards, should also be designed to ascertain
the frequency and severity of side effects. If further investigation of SGB for PTSD is prioritized
in VA, it should include a clear plan to address the following identified important limitations that
are also characteristic of research on conventional treatments for PTSD as a whole: (1)
adequately powering studies to measure clinically relevant benefits and harms; (2) improved
documentation of predominant PTSD symptom types, index trauma types, and comorbidities; (3)
improved documentation of prior and concomitant PTSD treatments; and (4) use of longer
follow-up periods to determine sustainability. We did not investigate whether SGB should be a
higher priority than other innovative treatments for PTSD, such as ketamine, MDMA (±3,4-
Methylenedioxymethamphetamine)-assisted psychotherapy, and cranial electrical stimulation, or
comparative costs.
Evidence Brief: Stellate Ganglion Block for PTSD Evidence-based Synthesis Program
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EVIDENCE BRIEF
INTRODUCTION
PURPOSE
The ESP Coordinating Center (ESP CC) is responding to a request from Office of Community
Engagement’s (OCE) Center for Compassionate Innovation (CCI) for an evidence brief on the
effectiveness of stellate ganglion block (SGB) for treatment of posttraumatic stress disorder
(PTSD). Findings from this evidence brief will be used to inform Subject Matter Experts’
consideration of clinical use and research and program prioritization for SGB for PTSD in VA.
BACKGROUND
Posttraumatic Stress Disorder (PTSD) and Its Impact
Posttraumatic stress disorder (PTSD) is a trauma- and stress-related disorder than can develop
following exposure to a traumatic event. PTSD can affect survivors not only of combat
experience, but any life-threatening event or traumatic emotional experience. According to the
Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (DSM-5), PTSD is defined
by 4 clusters of symptoms: (1) intrusive re-experiencing of a traumatic event, (2) avoidance of
trauma-related stimuli, (3) negative changes in mood and cognition, and (4) persistent
physiological arousal and reactivity. Diagnosis of PTSD requires that the symptoms significantly
impair functioning and last for at least one month.
1
PTSD is the third most common psychiatric diagnosis among Veterans seen in the Veterans
Health Administration (VHA).
2
The latest reports on VHA healthcare utilization by Operation
Enduring Freedom/ Operation Iraqi Freedom/ Operation New Dawn (OEF/OIF/OND) Veterans
shows that 378,993 Veterans have been diagnosed with PTSD at some point between FY 2002
and FY 2015.
3
The lifetime prevalence of PTSD in Veterans (12-30%)
4-9
has consistently been
found to be greater than that observed in the general population (7%).
10,11
According to research
summarized by the Department of Veterans Affairs National Center for PTSD (NCPTSD),
experts estimate that up to 20% of Operation Enduring Freedom and Operation Iraqi Freedom
(OEF/OIF) Veterans,
4-6
up to 12% of Gulf War Veterans,
7
and up to 30% of Vietnam War
Veterans
8,9
have experienced PTSD. Consequently, the need for PTSD treatment may increase
within the Veteran population in the coming years.
12
PTSD can be debilitating and lead to a decline in quality of life (QoL).
13
Mental health
impairments can include increased risk of suicide, depression, other mood/anxiety disorders,
eating disorders, and substance use disorders.
14-19
PTSD has also been linked to increased rate of
aging and early mortality.
20
Interpersonal and social impairments can include strained marital
and family relations, parenting difficulties, and difficulty finding and maintaining
employment.
21-26
As a result, overall healthcare service needs are high among people with
PTSD.
27
Congressional Budget Office data from fiscal years 2004 through 2009 indicate that,
compared to Veterans without PTSD, those with PTSD were more likely to use VHA healthcare
services in general regardless of their relationship to a PTSD diagnosis.
27
In 2015, the RAND
Center for Military Health Policy Research reported that for OEF/OIF Veterans with PTSD, the
Evidence Brief: Stellate Ganglion Block for PTSD Evidence-based Synthesis Program
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estimated 2-year costs to society from healthcare needs and lost productivitywere
substantial.
6
Challenges of Conventional Treatments
Commonly recommended first-line treatments for PTSD include psychotherapy,
pharmacotherapy, or their combination.
28-33
Examples of psychotherapy modalities used for
PTSD include: Exposure-based therapies (ET), Cognitive-based therapies (CPT), Stress
Inoculation Training (SIT), and Eye Movement Desensitization and Reprocessing (EMDR).
28
These psychotherapies include 5 core components: (1) narration, (2) cognitive restructuring, (3)
in vivo exposure, (4) stress inoculation skills (eg, relaxation), and (5) psychoeducation.
34
Pharmacotherapy for PTSD typically consists of antidepressants, such as selective serotonin
reuptake inhibitors (SSRIs) and serotonin norepinephrine reuptake inhibitors (SNRIs). If
unsuccessful, treatment may expand to mood stabilizers, anticonvulsants, antipsychotics, or other
agents.
However, several challenges have been identified in the effectiveness and reach of common
psychological and pharmacological treatments for PTSD.
34
The overall success of current PTSD
treatments is low and variable, with rates of remission generally ranging from 30% to 40%.
35,36
Whether treatment success differs based on particular clinical characteristics is largely
unknown.
35
According to surveys of Veterans with PTSD, barriers to seeking and accessing
treatment include concerns about treatment, emotional readiness for treatment, stigma, and
logistical difficulties.
37,38
Contributors to poor compliance with common psychological and
pharmacological treatments may include the many weeks to months required, potential side
effects, and co-morbidities.
39
Due to these limitations, there is a great need for innovative
approaches to further improving the health and well-being of people with PTSD.
What is Stellate Ganglion Block (SGB)?
The stellate ganglion, part of the sympathetic nervous system, is a cluster of nerve cell bodies
located between the C6 and C7 vertebrae. Injection of local anesthetic to the stellate ganglion, a
procedure known as stellate ganglion block (SGB), inhibits sympathetic nerve impulses to the
head, neck, and upper extremities. SGB is an outpatient procedure, performed by
anesthesiologists or interventional pain management physicians, that has been used to treat
various disorders including complex regional pain syndrome, hot flashes, migraines, facial pain,
and upper extremity pain.
Because the stellate ganglion is connected to brain regions thought to be abnormally activated in
PTSD, such as the amygdala, SGB has been explored as a potential alternative treatment option
for PTSD.
40
Studies that have examined brain imaging before and after PTSD treatment provide
potential evidence of this biological rationale for the effect of SGB on PTSD. A 2015 study
comparing fluorodeoxyglucose (FDG) PET brain scans of 5 Veterans with combat-related PTSD
one week before and after undergoing right-sided SGB found that the right amygdala and
hippocampal areas were relatively overactive when PSTD symptoms were more prominent.
41
A
2016 longitudinal study comparing functional MRIs and symptom scores of 72 Veterans with
and without PTSD during which PTSD patients received trauma-focused therapy suggested that
higher baseline dorsal anterior cingulate cortex (dACC), insula, and amygdala activation may
predict poor response to PTSD treatment.
42
Evidence Brief: Stellate Ganglion Block for PTSD Evidence-based Synthesis Program
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SGB has also been associated with biologic markers of sedation. A 2014 study on the effects of
SGB in rats found that SGB was associated with decreased EEG activity, suggesting a sedative
effect.
43
Similarly, a 2015 study of healthy adult volunteers found that SGB was associated with
a sedative effect compared to sham as measured by the bispectral index system (based on EEG)
and Observer’s Assessment of Alertness/Sedation scores.
44
The specific mechanism of action by which SGB may mitigate PTSD symptoms remains
incompletely understood. SGB results in peripheral vasodilation, but the mechanism by which
SGB impacts symptoms of PTSD is likely more complex. A proposed explanation for the
prolonged effectiveness of SGB on PTSD, as well as symptoms of hot flashes and complex
regional pain syndrome, is that application of local anesthetic to the stellate ganglion leads to a
reduction in nerve growth factor and a resulting decrease in sympathetic nerve sprouting and
brain norepinephrine levels.
45
Ropivacaine or bupivacaine, 7 cc of 0.5% solution, are the most common anesthetic types and
dosages used in SGB.
39
To avoid potential serious adverse effects of inaccurate needle placement
to the anatomy surrounding the stellate ganglion, use of image-guidance techniques such as
ultrasound, fluoroscopy, or computed tomography are recommended to help visualize the
injection area. SGB performance also requires the availability of continuous vital sign
monitoring technology and resuscitative equipment and personnel to monitor and respond to
changes in respiration and circulation that may occur as a result of unintentional intravascular
injections. Identification of a successful SGB is made by diagnosing temporary Horner’s
syndrome occurring within 15 minutes of the procedure – a constricted pupil, weak and droopy
eyelid, decreased sweating, and potential inset eyeball – which is recommended to be
quantitatively graded by a third-party medical professional.
46
Regulation, Guidance, and Advocacy for SGB
Ropivacaine and bupivacaine are FDA-approved for production of local or regional anesthesia
for surgery and acute pain management, including in the head and neck area. Injection of these
drugs into the stellate ganglion for PTSD is considered an “off-label” use for a different disease
than described in the drug label, which is legal and unregulated. PTSD treatment guidelines from
the VA/DoD and other professional societies do not reference SGB,
28,29,33
but in 2015,
Lieutenant Colonel Sean W. Mulvaney, MD and colleagues published clinical guidelines in the
Journal of Special Operations Medicine.
46
The main source of public advocacy for SGB for
PTSD comes from pain management anesthesiologist, Eugene Lipov, MD, who founded the
Global Post-Traumatic Stress Injury Foundation (GPTSIF) to facilitate access to innovative
biological treatment for PTSD,
47
and who has made numerous network television appearances
and authored numerous articles about SGB for PTSD.
48-52
Advocates such as Drs. Lipov and
Mulvaney have promoted SGB for PTSD primarily based on the notably high rates of clinically
meaningful improvement (70% to 75%) in uncontrolled case series of predominantly males in
their early forties who were active-duty military with combat-related PTSD.
39,53,54
Advocates
commonly describe SGB as safe, with the most frequently cited supporting evidence coming
from a questionnaire survey with a 51% response rate that included responses from 39 West
German departments of anesthesiology, representing approximately 45,000 SGBs, that reported
low rates (1.7 per 1000) of severe complications such as convulsions.
55
Evidence Brief: Stellate Ganglion Block for PTSD Evidence-based Synthesis Program
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What Are Possible Roles for SGB for PTSD?
SGB for PTSD has typically been promoted as an adjuvant in individuals who have not fully
responded to conventional therapies.
53
Some proposed benefits of SGB for PTSD include (1) it
may destigmatize treatment by offering a biologic approach to PTSD management,
39
(2) it may
offer a faster-acting treatment alternative with improvements reported within 30 minutes to days
of the procedure,
39
and (3) it increases compliance as it does not require continuous daily or
weekly administration.
53
Objectives of this Evidence Review
Our objectives were (1) to determine to what extent SGB provides clinically relevant benefits for
patients with PTSD, (2) to determine SGBs potential harms, and (3) to identify patients who are
most likely to benefit from SGB.
METHODS
The ESP included studies that met the following criteria:
· Population: Adults with posttraumatic stress disorder (PTSD)
· Intervention: Stellate ganglion block (SGB)
· Comparator: Any
· Outcomes:
o Clinical health outcomes: Remission and % of patients achieving minimally
important difference in PTSD symptom scores (% responding). Although no
definitive guidance has been established for prioritization of instruments and
thresholds to use to best measure clinically significant improvement in PTSD
symptoms, we used these as our general guideposts: ≥ 15-point reduction on
the Clinically-Administered PTSD Scale (CAPS),
56
a ≥ 10-point reduction on
the PTSD Checklist (PCL)
57
and a ≥ 30% reduction in general
58
o Intermediate benefits: Change in symptom scale scores for PTSD, depression,
functional status, quality of life
· Harms: Complications including arrhythmia; hypotension; hematoma due to injury to
adjacent vascular structures; thoracic duct injury; injection of local anesthetic into the
intravascular, intrathecal, epidural space, or brachial plexus; direct spread of local
anesthetic to the recurrent laryngeal or phrenic nerves; soft tissue infection; osteitis;
and meningitis
· Timing: Any study follow-up durations
· Setting: Any
· Study design: Systematic reviews, randomized controlled trials, or concurrently
controlled cohort studies. Case series will be briefly discussed to provide frequently
cited context, but will not be formally evaluated due to their inherent weaknesses
59,60
Evidence Brief: Stellate Ganglion Block for PTSD Evidence-based Synthesis Program
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To identify articles relevant to the key questions, we searched MEDLINE®, the Cochrane
Central Register of Controlled Trials, the Cochrane Database of Systematic Reviews, CINAHL,
PsychINFO, and PILOTS on 12/30/2016 and updated on 2/7/2017, using terms for stellate
ganglion block and PTSD. (See Appendix A in the supplemental materials for complete search
strategies.) We limited the search to articles involving human subjects available in the English
language. We sought additional citations through hand-searching reference lists, relevant
journals, and consultation with content experts. Study selection was based on the eligibility
criteria described above. We searched numerous other sources to identify unpublished and less-
accessible forms of data (Appendix A in supplemental materials). Titles, abstracts, and full-text
articles were reviewed by one investigator and checked by another. All disagreements were
resolved by consensus.
Four reviewers (KP, DB, JA, KM) independently assessed the internal validity of the randomized
controlled trial using criteria established by the Drug Effectiveness Review Project.
61
This
approach involves assigning ratings of good, fair, or poor quality to reflect the adequacy of
methods for randomization, allocation concealment, blinding, outcome measurement and
analysis, and acceptability of levels of adherence and attrition. One reviewer abstracted data
from the randomized controlled trial on its design, patient characteristics, and results for each
included outcome and these were then checked by another. All disagreements were resolved by
consensus.
We graded the strength of the evidence based on the AHRQ Methods Guide for Comparative
Effectiveness Reviews.
62
This approach incorporates 4 key domains: risk of bias (includes study
design and aggregate quality), consistency, directness, and precision of the evidence. It also
considers other optional domains that may be relevant for some scenarios, such as a dose-
response association, plausible confounding that would decrease the observed effect, strength of
association (magnitude of effect), and publication bias. Strength of evidence is graded for each
key outcome measure and ratings range from high to insufficient, reflecting our confidence that
the evidence reflects the true effect. Strength of evidence grades were first completed by one
reviewer and checked by another and all disagreements were resolved using consensus.
A draft version of this report was reviewed by 3 technical experts and clinical leadership. Their
comments and our responses are presented in the supplemental materials.
The complete description of our full methods can be found on the PROSPERO international
prospective register of systematic reviews (http://www.crd.york.ac.uk/PROSPERO/; registration
number CRD42016053908).
Evidence Brief: Stellate Ganglion Block for PTSD Evidence-based Synthesis Program
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RESULTS
LITERATURE FLOW
Searches resulted in 174 potentially relevant articles after removal of duplicates (Figure 1). Of
these, we identified one study with a concurrent comparison group, which was an RCT.
63
Detailed reasons for exclusion are provided in Appendix B of the supplemental materials.
Figure 1: Literature Flowchart
TO WHAT EXTENT DOES SGB PROVIDE CLINICALLY RELEVANT
BENEFITS FOR PTSD?
Case Series
Uncontrolled case series of predominantly males in their early forties who were active-duty
military with combat-related PTSD (N=202) have found high rates of clinically meaningful
improvement with SGB (70% to 75%),
39,64,65
including in those with extreme PTSD.
65
Case
series can be valuable in providing an initial indication of promise. However, their lack of a
control group is a major drawback that prevents drawing conclusions regarding treatment
effect.
60
For example, it is quite common to see very encouraging results in a few case series,
followed by smaller benefits or contradictory findings in subsequent RCTs.
66
10 records identified through
reference lists and hand searching
155 titles and abstracts excluded
19 full-text articles assessed for eligibility
18 full-text articles excluded
(See supplementary materials for
exclude reasons)
1 comparative study included in synthesis
249 records identified through database
searching (Date: 12/2016)
89 records from Medline
27 records from CINAHL
13 records from Cochrane
22 records from PsychINFO
98 records from PILOTS
174 titles/abstracts screened for eligibility after removal of duplicates
Evidence Brief: Stellate Ganglion Block for PTSD Evidence-based Synthesis Program
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Randomized Trials
To date there is only one published randomized trial on SGB for PTSD.
63
This study compared
ultrasound-guided SGB with 5 cc of 0.5% ropivacaine to an inactive sham procedure with
normal saline, in 42 primarily limited-duty male military participants with both combat and
noncombat PTSD.
63
SGB was administered on the right side of the neck, generally at the C6
level. The main finding of this RCT was that at one week and one month after the first round of
treatment, the magnitude of mean reduction in PTSD symptoms for SGB and sham neither met
the proposed criteria for clinical relevance nor were different between groups, regardless of
whether they were measured based on the Clinically-Administered PTSD Scale (CAPS) or the
PTSD Checklist (PCL) (Table 1). In the subset of patients who received a second round of SGB
or sham, the SBG group reached a clinically significant reduction after one week based on the
CAPS, but not the PCL, but again there were no significant differences between SGB and sham.
Because these findings come from a single study with imprecise findings, moderate
methodological limitations, and did not directly focus on clinically relevant outcomes or use the
most common administration techniques, they provide an insufficient basis upon which to draw
conclusions about SGB for treatment of PTSD in Veterans. Although this study did well in using
blinded outcome assessors, we rated the methodological quality of this trial as fair because there
were more active-duty participants in the SGB group (96% vs 73%), attrition was high overall
(57%) primarily due to “lost to follow-up at 3 month post treatment or completed outside of 3
month post treatment window” – and was higher in the SGB group (67% vs 40%), and the study
did not report on or account for potential between-group differences in concurrent PTSD
treatments. Although no definitive guidance has been established for prioritization of instruments
and thresholds to use to best measure clinically significant improvement in PTSD symptoms, this
trial did not report on the key outcomes that have been suggested as general guideposts: ≥ 10- to
15-point reduction on the CAPS,
56
a ≥ 10-point reduction on the PCL,
57
and/or a ≥ 30%
reduction in general.
58
Although in previous case series the most commonly used anesthetic type
and dosage used have been 7 cc of ropivacaine, or bupivacaine 0.5% solution, this trial used 5 cc
ropivacaine, a 28%-lower dose, and provided no rationale for doing so. Also, it is unclear
whether the ropivacaine injection actually reached the stellate ganglion in all patients. Although
the stellate ganglion is typically located at C6 to C7, the level of target needle placement was C5
to C6 in this study. Although the study author confirmed that the injection was “typically” at C6,
some could have been at C5 and missed the stellate ganglion. Other commonly criticized
limitations of this trial that may have altered SGB effects include that (1) it used an inappropriate
population who were in the process of disability evaluation and may have had secondary
financial incentives to resist treatment,
63,67
and (2) the use of saline instead of an active control
that mimicked the side effects of SGB was potentially inadequate and may have reduced the
effectiveness of the blinding, as patients may have been able to easily tell if they received SGB
or sham based on the occurrence of the Horner’s syndrome eye droop. Effectiveness of the
blinding was not formally assessed.
Evidence Brief: Stellate Ganglion Block for PTSD Evidence-based Synthesis Program
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Table 1. Mean Change from Baseline for SGB versus Sham in the RCT
First Round
Second Round
One week
One month
One week
One month
Scale
SGB
Sham
SGB
Sham
SGB
Sham
SGB
Sham
CAPS
-12.7
N=27
-11.3
N=15
-6.6
N=27
-8.8
N=14
-17.8
N=18
-9
N=12
-7.8
N=14
-4.3
N=12
PCL
-3.6
N=26
-4.1
N=15
-2.0
N=27
-2.4
N=13
-7.9
N=17
-4.6
N=12
-6.5
N=12
-6.3
N=12
Abbreviations: CAPS = Clinically-Administered PTSD Scale; PCL = PTSD Checklist; SGB = Stellate Ganglion
Block
WHAT ARE SGB’S POTENTIAL HARMS?
Substantial uncertainty remains about the potential serious harms of SGB due to a lack of
adequately powered studies using clearly reliable and valid assessment methods. Although the
frequently cited 1992 West German questionnaire survey of approximately 45,000 SGBs from
39 anesthesiology departments appears to provide the most precise estimates of serious
complications, it has important methodological weaknesses that seriously limit our confidence in
its findings. At 1.7 per 1000, rates of severe complications, such as convulsions, were reportedly
low in this questionnaire survey.
55
However, we have no information about what methods were
used to collect and analyze these data, such as the rating criteria used, how they were
implemented, what the time period was between the procedure and outcome assessment, what
data monitoring standards were used to reduce error, the level of which and how missing data
were handled, and how consistent these factors were across departments. Without this
information, we cannot be sure of the reliability and validity of these data. Compared to the
“blind” technique used in the West German SGBs from the survey, we agree that the modern
standard of using image-guidance techniques has the potential to increase needle placement
accuracy and result in lower severe complications than reported in this survey. However, we
have no way of knowing how much or in what direction the potential limitations in the outcome
assessment methods may affect the reported rates.
Although RCTs of SGB for PTSD,
63
and CPRS,
68
and case series of SGB for PTSD,
39,54,69
may
have used stronger assessment methods, their findings are limited by imprecision and do not
importantly improve our knowledge about the risk of serious complications. In the RCT and case
series of SGB for PTSD,
63
there were no instances of serious complication such as arrhythmia,
hypotension, hematoma due to injury to adjacent vascular structures, thoracic duct injury,
injection of local anesthetic into the intravascular, intrathecal, or epidural space or brachial
plexus, direct spread of local anesthetic to the recurrent laryngeal or phrenic nerves, soft tissue
infection, osteitis, or meningitis. In the RCT,
63
after one month post-injection, 28 mild adverse
events were recorded, resulting in a potential complication rate of 33%. An IRB-designated
scientific reviewer categorized the adverse events as “Unrelated,” “Remote,” “Possible,” or
“Related.” Ten of the events were classified as “Related” or “Possible,” for a complication rate
of 12%. There was no significant difference in the rate of complications between the SGB and
sham injection groups. Complications included increased injection site pain, which could
potentially have been reduced by using a smaller needle such as in prior studies (20 gauge in
RCT vs 22-25 gauge in case series). The most notable event was prolonged eye drooping, which
was observed in one patient and resolved after 4 days.
Evidence Brief: Stellate Ganglion Block for PTSD Evidence-based Synthesis Program
11
Because of the limited data on harms for SGB in PTSD, we looked to the larger literature on its
use for CRPS. A 2016 Cochrane review on sympathetic blockades for CRPS identified 3 studies
that provided specific data regarding adverse effects of SGB for CRPS (N=115).
68
Adverse event
rates ranged from 0% to 14.3% and included significant nausea and emesis, paresthesia during
needle positioning, pain at the injection site, varying rates of drowsiness, dizziness, or hoarseness
based on the anesthetic used, increased pain, headache, dysphagia, hematoma, dyspnea,
shivering, cold feeling, face swelling, mouth numbness, and blurred vision. The most prevalent
complaint was pain at the injection site. Due to the small size of the included studies, Cochrane
review authors could not draw conclusions regarding the safety of sympathetic blockades.
WHO IS MOST LIKELY TO BENEFIT?
There is insufficient information to determine which Veterans, if any, are most likely to benefit
from SGB for PTSD. We found no studies that compared outcomes between subgroups of
patients with different demographics, predominant PTSD symptom clusters, or comorbidities.
Findings from a case series of 30 active-duty military service members with combat-related
PTSD suggest that people with predominantly hyperarousal and avoidance types of symptoms
may be more likely to benefit from SGB.
70
Evidence for this effect is very weak as it is based on
inference from evaluation of which symptoms are most impacted after SGB, rather than from
direct comparison of response rates between people with different levels of these symptoms at
baseline.
SUMMARY AND DISCUSSION
Emergence of an intervention’s first randomized trial is always a highly anticipated event. For
SGB, however, findings from its first randomized trial for PTSD proved to be disappointing. In
uncontrolled, unblinded, retrospective case series, SGB for PTSD had high rates of rapid clinical
improvement in PTSD symptoms (70% to 75%). In the RCT, the range of mean percent PTSD
improvement after one round of SGB was 5.4% to 14.7%, and was 12.1% to 21.2% after the
second round, which was no better than an injection of saline. The RCT was too small to
estimate complication rates and did not report the number of patients in each group, if any, who
responded to treatment. Instead it reported group averages. What do we make of this? It is not
surprising that SGB’s benefits were less impressive in the RCT than in the case series, as
empirical evaluation has shown that, on average, benefits are generally larger in observational
studies.
66
However, what was surprising is that by using a somewhat lower than usual dose of
ropivacaine (5 cc versus 7 cc) and a population that may have been motivated to resist treatment,
design features may have limited the RCT’s chances of generating meaningful data on efficacy.
71
Substantial uncertainty remains about the potential harms of SGB as well, as the RCT and
previous case series in PTSD, as well as RCTs for CRPS,
68
were inadequately powered to
support or refute findings from the 1992 German questionnaire survey of 45,000 SGBs. We
agree with the conclusions of previous reviews that further research is needed to more precisely
determine the balance of benefits and harms of SGB for PTSD.
39,52,72
LIMITATIONS
Overall, a key limitation of the evidence on SGB is that it is based primarily on uncontrolled,
unblinded studies. Also key is that evidence on SGB for PTSD has unclear applicability to
Veterans. Although most studies have been conducted in military populations, the majority were
Evidence Brief: Stellate Ganglion Block for PTSD Evidence-based Synthesis Program
12
active-duty military members. In the largest case series (N = 166), a majority of participants
continued exposure to combat after treatment.
54
The majority of study participants were male, as
in VA, but mean age was late thirties to early forties and prevalence of depression, anxiety, pain,
and other medical comorbidities was unclear.
The limitations of the evidence base for SGB for PTSD are similar to those for other PTSD
treatments.
35
First, SGB studies have generally been underpowered to adequately measure the
most clinically important outcomes of remission, response, and serious adverse events. Second,
although SGB has been recommended for use as an adjuvant for other therapies,
53
evidence is
insufficient to support recommendations about specifically when to initiate SGB in the order of
recommended conventional pharmacotherapies and psychotherapies. How much failed
conventional therapy is “enough” before trying SGB? Although likely many study participants
had already failed “gold standard” therapy and their lack of success suggests the need for an
innovative approach, the studies’ lack of specific criteria for establishing “failure” of
conventional therapy, and/or dose and duration and order of conventional therapies makes it
difficult for readers to compare their patient with those in the studies. For example, in the largest
case series of N = 166, only 3% of patients were taking psychotropic medication before SGB and
there was no information about dose and duration and no information about any psychotherapy.
54
In the RCT, the only information about other mental health treatments was that 9.5% participated
since deployment, 26% during deployment, and 69% after deployment, but no details were
provided about type or duration.
63
Third, there was insufficient information to determine
applicability to and which Veterans, if any, are most likely to benefit from SGB for PTSD, due to
inadequate documentation of predominant PTSD symptom types, index trauma types,
comorbidities, optimization of prior dose, and duration of prior treatments. Fourth, evidence is
insufficient to fully assess the clinical relevance of the benefits of SGB for PTSD. Although the
studies consistently used the recommended tools – the CAPS and the PCL – none assessed
remission (loss of PTSD diagnosis). Although the largest case series measured proportion of
patients who were “responders” using the recommended PCL criteria of a ≥ 10-point reduction,
the RCT did not measure the proportion of patients meeting any clinically relevant threshold.
Finally, we could not assess long-term sustainability of response as follow-up was generally
limited to 3 months post-SGB.
Publication bias is the primary potential limitation of our review process. We attempted to
minimize the risk of publication bias by specifically searching for unpublished studies, and we
did not find any negative case series or previously unreported outcomes. Nonetheless, we may
have missed such data.
CLINICAL AND RESEARCH IMPLICATIONS
SGB for PTSD has been recommended for use as an adjuvant in individuals who have not fully
responded to conventional therapies.
53
Other practical considerations that may guide treatment
decisions include access to, contraindications for, and patient preference for SGB. Access to
SGB may require efforts to increase psychiatrists’ education about SGB and promote
development of partnerships between psychiatry and anesthesiology and pain management
specialists.
39
Contraindications for SGB may include a history of an anesthetic allergy, and
because of the potential risks of ocular, cardiac, and circulatory adverse events, SGB should be
avoided in individuals with coagulopathy, a recent cardiac infarction, a severe conduction block,
or glaucoma.
73
Finally, although those who have undergone SGB have found it highly
Evidence Brief: Stellate Ganglion Block for PTSD Evidence-based Synthesis Program
13
acceptable,
69
the invasive nature of SGB may be a barrier for some candidates to try it in the first
place.
SGB for PTSD is currently supported only by evidence from uncontrolled, unblinded case series
which was neither confirmed nor refuted by a single RCT with imprecise findings, moderate
methodological limitations, and which did not directly focus on clinically relevant outcomes. In
currently used evidence grading systems,
62
such evidence is considered “insufficient” for
estimating an effect. More rigorous studies are needed to more precisely determine the balance
of benefits and harms of SGB for the treatment of PTSD. Both randomized trials and
observational studies can contribute to our knowledge of SGB for PTSD. RTI International is
conducting a U.S. Army-funded randomized trial that will compare SGB to placebo in a planned
enrollment of 204 active-duty military personnel with PTSD (US Army Medical Research
Acquisition Activity, grant number W81XWH-15-2-0015).
74
This trial will help answer the
overarching question of whether SGB is effective, but follow-up is only 8 weeks and it is not
expected to address all of the gaps in the existing evidence.
We agree with Dr. Lipov
53
that the VA could be an ideal setting to perform further practice-
based research on SGB for PTSD to evaluate remission, response, and serious complication
rates, with follow-up longer than 8 weeks. An observational design could be appropriate, but it
should be incorporate precautions against bias that were lacking in prior studies. In particular,
1) Rigorous standards for registry studies should be followed (see below);
2) Assessment of preferences as part of the research protocol;
3) Inclusion of Veterans with PTSD who are offered (and either do or do not undergo)
conventional treatments, followed prior to and after consideration of SGB; and
4) Outcome assessment and data analysis should be conducted by research or quality
improvement personnel who do not have strong prior views of the effectiveness of
SGB.
In addition, future VA research on SBG should include a clear plan to address shortcomings of
previous research through use of the following rigorous standards for registry studies: (1)
sufficient sample size to assess the clinically relevant benefits and harms; (2) improved
documentation of predominant PTSD symptom types, index trauma types, and comorbidities; (3)
improved documentation of prior and concomitant PTSD treatments; and (4) longer follow-up
periods.
A controlled observational study designed in this way could provide better justification for
conducting another RCT to strengthen our certainty about the benefits. If a future RCT is
undertaken, we also suggest considering adding functional magnetic resonance imaging (fMRI)
assessment both to improve our understanding of SGB’s neural mechanisms and to help clarify
the impact of inadequate blinding. Differences in fMRI results between SGB and control group
participants could help refute an argument that clinical differences were due to knowing whether
or not they got SGB.
We did not investigate whether SGB should be a higher priority than other innovative treatments
for PTSD. Examples of other potentially rapid and innovative treatments include ketamine,
Evidence Brief: Stellate Ganglion Block for PTSD Evidence-based Synthesis Program
14
MDMA (±3,4-Methylenedioxymethamphetamine)-assisted psychotherapy, and cranial electrical
stimulation. Each has their own unique set of potential harms, such as addiction and
neurotoxicity, which would have to be considered in relation to SGB’s net benefits. Cost of these
innovative treatments compared to conventional psychotherapy and pharmacotherapies should
also be assessed in the prioritization process. SGB costs have been estimated to be lower than
conventional PTSD therapies ($2,000 for two SGB injections vs a range of $6,000 to $30,000).
75
However, we have not formally evaluated comparative costs or how these estimates apply to the
current VA environment.
For additional related evidence review work, we recommend that a review of the state of the
science of PTSD outcome assessment methods, such as has been done in the field of chronic pain
outcome assessment,
76
could be useful in informing the direction of future research for PTSD as
a whole.
CONCLUSIONS
Findings from the first RCT of SGB for PTSD were inconclusive, neither confirming nor
refuting findings of rapid and high rates of clinically relevant improvement and low risk of
serious adverse events from unblinded, uncontrolled case series. It is appropriate to listen to
criticism of the RCT, envision a better study of SGB for PTSD, and investigate whether SGB
should be a higher priority than other innovative treatments for PTSD.
Evidence Brief: Stellate Ganglion Block for PTSD Evidence-based Synthesis Program
15
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