American Society of Regional Anesthesia and Pain Medicine May 2017 - 11

laryngeal nerve blocks, inadvertent intrathecal and epidural
injections, as well as hematoma-induced respiratory insufficiency
and local anesthetic systemic toxicity.
The stellate ganglion is a structure in the sympathetic chain
commonly found at the level of the 7th cervical vertebra. In 80%
of cases, it is a single ganglion formed by fusion of the inferior
cervical sympathetic ganglion and the first thoracic sympathetic
ganglion; in the remainder of individuals, it is two ganglia in close
proximity. By the 1930s, clinicians recognized that injecting local
anesthetic into the stellate ganglion, known as a stellate ganglion
block, inhibited both efferent sympathetic fibers and visceral pain
fibers to the upper extremity and face.6 SGB is now commonly used
for the treatment of hypersympathetic activity influencing the upper
extremity, such as Raynaud's phenomenon, or in sympathetically
mediated pain as may be present in complex regional pain
syndrome.

in 2010 was a turning point in the study of SGBs for PTSD, as
it was the first study to use standard outcome measures and to
collect data prospectively. Randomized controlled trials and largescale registry data were clearly absent despite widespread clinical
use of the procedure.
The first randomized, blinded, sham-controlled study to evaluate
the efficacy of SGB on PTSD symptoms in a military population was
published in Regional Anesthesia and Pain Medicine in 2016.15 In
addition to patient-reported symptom severity scores, such as the
PTSD Checklist (PCL), this study was the first to require a diagnosis
of PTSD by a psychiatrist and used the Clinician-Administered PTSD
Scale (CAPS).
Although previous case series have suggested SGBs offer an
effective intervention for PTSD, this study did not demonstrate
any appreciable difference
between SGB and sham
treatment. The results
indicated that observed
PTSD symptoms (CAPS)
improved in participants in
both the active and sham
groups. This was also true
for self-reported scores
for depression (Patient Health Questionnaire), and anxiety (Beck
Anxiety Inventory), but not for self-reported PTSD scores (PCL) or
pain (visual analogue scale). The overall magnitude of improvement
was modest, less than previously reported in case series.
Moreover, improvement with the SGB was not superior to the sham
intervention.

"Current evidence-based PTSD
therapies are not without challenges
and have limited reach and impact."

In 1947, Karnosh and Gardner7
reported a series of cases in
which SGBs were used to treat
depression. The technique,
however, largely was forgotten
as a psychiatric treatment
until recent cases and popular
press reports of SGBs being used to treat PTSD, alcoholism, and
menopause.8-14 The mechanism of action of an SGB's ability to
mitigate symptoms in patients with PTSD is unknown. Proposed
mechanisms for the SGB's benefit in patients with a psychiatric
condition include downregulation of norepinephrine and/or nerve
growth factor. A second theory notes that the SGB procedure should
be performed on the right side for patients with PTSD. This proposal
is likely because initial case series happened to be performed
in patients with right upper extremity pain conditions and PTSD.
Correlation with current functional MRI studies has not provided a
convincing model to date.
Despite the limited understanding of the mechanism of action of
right-sided SGBs to mitigate PTSD symptoms, coupled with the
possibility of rare, but catastrophic risks, the appeal for a rapidly
acting treatment modality with long duration of action is highly
desirable in light of the rising tide of PTSD. Equal to that appeal is
the need for further research on the topic to ensure efficacy and
safety of SGBs for PTSD.
Table 1 summarizes the entire body of published work on SGBs and
PTSD at the time the Naval Medical Center San Diego initiated the
first randomized controlled trial on this topic.15 Previous published
work was entirely composed of case series, totaling 27 patients.
Each of these case series had significant methodologic flaws, the
most notable being inconsistent follow-up. However, it should be
pointed out that a study by Mulvaney et al11 on military populations

The results of this randomized controlled trial differed significantly
from a larger retrospective study previously published in the
journal Military Medicine in 2014 by Mulvaney et al.16 Mulvaney
and colleagues16 observed the response that active duty military
patients suffering from combat-related PTSD symptoms had to
treatment with SGBs. The authors used a well-validated PTSD
symptom severity scale (PCL-Military [PCL-M]) and considered
a 10-point change as indicative of a clinically significant
improvement. The PCL-M was collected at baseline, 1 week, and
each month after treatment up to 6 months. If patients had an initial
response and PCL scores after 3 months returned to or were near
baseline, they were offered another SGB. In this nonrandomized
data set, most patients responded within the first week (79%).
This phenomenal response rate seemed to persist at each data
collection point (82% at 1-2 months, 74% at 3-6 months). Not only
was the response rate significant, but the degree of the response
was remarkable with a 22-point average reduction observed.
It is interesting to consider why the results from this study differed
so significantly from the randomized trial performed in a similar

American Society of Regional Anesthesia and Pain Medicine
2017

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Table of Contents for the Digital Edition of American Society of Regional Anesthesia and Pain Medicine May 2017