NATIONAL HARBOR, MD — While promising preliminary research has shown some benefits of stellate ganglion block (SGB) for post-traumatic stress disorder (PTSD), a new randomized controlled trial shows the treatment is not superior to sham injection.
An increasing number of case reports showing benefits from SGB for PTSD for several months after treatment has generated much buzz in the popular press, and the treatment has recently been featured on various TV programs.
One of the largest studies of the treatment to date was a case series involving 166 patients at Walter Reed National Military Medical Center, in which 70% of military service members with PTSD reported significant improvement of their PTSD symptoms, with benefits persisting beyond 3 and 6 months after the procedure.
Robert N. McLay, MD, PhD, lead author of the new study, said such improvements were seen even in a small case series of patients with PTSD at his center, prompting the placebo-controlled study.
"We were hoping for a benefit," Dr McLay, of the Naval Medical Center, in San Diego, California, told Medscape Medical News.
"We tried this out informally in our clinic and did see some benefit in about half of patients, but in this more formal study we were not able to reproduce those results."
For the new study, presented here at the American Academy of Pain Medicine (AAPM) 31st Annual Meeting, Dr McLay and his colleagues recruited 42 military service members with PTSD. The participants were randomly assigned in a double-blind fashion to treatment with SGB (n = 27), involving an injection of 7 mL of 0.5% ropivacaine, or a sham saline injection (n = 15).
Using ultrasound guidance over the C5 or C6 vertebrae, the SGB was made in the right C6 vertebra. The block's efficacy was confirmed by the presence of Horner's sign and a temperature drop in the right upper extremity.
In follow-up assessments of measures on the clinician-administered PTSD Scale (CAPS) at 1 week and 1 month after the procedure, significant improvements were made in both groups (P < .01). However, there were no significant differences between the treatment and sham groups.
Following the 1-month assessment, 19 patients in the treatment group received a second SGB injection, and 14 control patients in the sham control group crossed over and received one injection.
A repeated assessment again showed a significant improvement in both groups at a 1-month follow-up compared with pretreatment CAPS scores (P < .05). Again, however, there were no significant differences between the groups.
Among the patients who received two SGB injections and in the sham crossover patients, there a trend toward statistical significance in the change in CAPS scores was seen between the first and second injection (P < .05). However, because the second injection was not blinded, the findings cannot be considered definitive, Dr McLay said.
The suspected mechanism in treating PTSD has been the effect of SGB in blocking the sympathetic outflow, Dr McLay explained. "The stellate ganglion is a major fight-or-flight outflow and it's the highest, the closest, to the brain that we can access, so that has been the theory."
He noted that while treatments such as cognitive-behavioral therapy and exposure therapy have been shown to be very effective in the treatment of PTSD, the nature of the disorder itself can impede commitment.
"There are good treatments for PTSD, but they are very slow and arduous and people have to have a big commitment to it, and that's a hard thing to do in a condition where avoidance is part of the symptoms," Dr McLay said.
"People don't like to leave their homes, much less go to a therapy appointment twice a week to talk about the thing they least want to talk about in the world," he said.
"If we could be able to tell patients to come into the office just once and get an SGB injection and hour later they'll be better, we could reach a heck of a lot more people, if it truly worked."
The findings underscore the importance of vetting all treatments, particularly those that seem most promising, said Daniella David, MD, a professor of psychiatry at the University of Miami and chief of psychiatry and PTSD at the Veterans Affairs Medical Center in Miami, Florida.
"There are many treatments that have been tried for chronic PTSD in combat vets, due to the severity and chronicity of the disease," she told Medscape Medical News.
"It's crucial to conduct randomized controlled trials, as that's the only way to scientifically assess the effectiveness of a treatment intervention."
Despite the buzz about a role for SGB in PTSD treatment, the results don't bode well for the treatment's potential, she added.
"I have read about the stellate ganglion block and considered it an unlikely-to-succeed treatment intervention for PTSD. I think this study shows it to be ineffective and I don't believe it's worth pursuing."
The study received support from the US Navy Bureau of Medicine and Surgery. Dr McLay and Dr David have disclosed no relevant financial relationships.
American Academy of Pain Medicine (AAPM) 31st Annual Meeting. Abstract 126. Presented March 20, 2015.
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Cite this: Stellate Ganglion Block No Better Than Placebo for PTSD - Medscape - Mar 26, 2015.