Five-Minute Injection May Offer an Effective Option for PTSD

Pauline Anderson

November 07, 2019

A quick injection that blocks the stellate ganglion relieves symptoms of posttraumatic stress disorder (PTSD) and may represent a new and urgently needed treatment option.

Results of a randomized, sham-controlled trial in active-duty military members showed that stellate ganglion block (SGB) relieved distress, anxiety, and depression in this cohort.

Interestingly, those with the most severe PTSD achieved the greatest benefit.

Kristine Rae Olmsted, MSPH

"SGB can represent a new treatment option for PTSD but should be used as much as possible in concert with psychotherapy," principal investigator Kristine L. Rae Olmsted, MSPH, a research epidemiologist at Research Triangle Institute, Durham, North Carolina, told Medscape Medical News.

The study was published online November 6 in JAMA Psychiatry.

Five-Minute Procedure

Research suggests that extreme trauma may stimulate the sympathetic nervous system. The stellate ganglion, a collection of nerves located at the base of the neck, is part of that nervous system and is "sort of a weigh station for the fight or flight" reaction, said Rae Olmsted.

The SGB procedure involves injecting a short-acting local anesthetic in and around the stellate ganglion to temporarily block its function. The procedure is "very quick," taking only about 5 minutes, said Rae Olmsted.

It's unclear how SGB works with respect to PTSD, but some experts believe it "reboots" the sympathetic nervous system to its pretrauma state, perhaps by providing feedback to the amygdala, which is closely aligned with emotional processing.

The procedure isn't new; it has been used to treat pain conditions since the 1940s. Several case studies showed promising results in patients with PTSD, although in one clinical trial, the results were negative.

The new study included 113 active-duty military personnel (100 men and 13 women; mean age, 37.3 years) at three sites. Participants were required to have been diagnosed with PTSD and to have been stable through the use of psychotropic medication for a period of at least 3 months. Patients were excluded from the study if they had a history of moderate or severe traumatic brain injury.

Patients were randomly assigned to receive two right-sided SGB treatments or sham procedures 2 weeks apart. None of the participants had a patient-physician relationship with the clinician who administered the treatment.

Those in the active-SGB group were injected with 7 to 10 mL of ropivacaine 0.5% around and into the ganglion at the level of the C6 anterior tubercle. The sham-treatment group received 1 to 2 mL of preservative-free normal saline injected into deep musculature anterolateral to the anterior tubercle of C6.

Participants were blinded with respect to which procedure they received; drapes were used to limit their field of vision. Although clinicians could not be blinded, their interactions with participants were scripted.

Of the total, 108 individuals (95.6%) remained in the study through the 8-week follow-up.

The study's primary outcome was change in overall total symptom severity scores on the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5). Scores on that scale range from 0 to 80 points, with higher scores indicating greater PTSD symptom severity. A 10-point change in the CAPS score was considered clinically meaningful.

The analysis showed that at 8 weeks, the SGB group benefited more than the sham-treatment participants. The mean symptom change after adjustment for study site and baseline CAPS-5 score was –12.6 points for SGB group compared with –6.1 points for the sham-treatment group, which represented a significant difference.

The treatment appeared to work better for those with more severe PTSD symptoms. For each 1-point increase in initial CAPS-5 score, there was an estimated additional 0.2-point reduction at 8 weeks.

Unclear Mechanism

The reasons for this are unclear, but other studies have reported similar findings, said Rae Olmsted. She speculated that patients with more severe symptoms may have "more opportunity to get better."

Secondary outcomes included scores for a number of symptoms highly correlated with PTSD, including depression, distress, anxiety, pain, physical functioning, and mental functioning. For all these outcomes, those receiving SGB had significantly improved scores on relevant scales compared with those receiving the sham procedure.

Six adverse events were reported, including coughing as well as pain and redness at the injection site. None of these were serious.

The new results contrast with those of the first pilot, randomized clinical trial of SGB for combat-associated PTSD. That study did not find a significant difference between the SGB group and the saline-injection control group.

The authors note the following differences between that study and the current one: the previous was smaller; it included a single site; it used only one SGB instead of two; it utilized less ropivacaine; and exclusion criteria were less rigorous.

The potential for participants to recognize signs of Horner syndrome is a limitation of the study. Horner syndrome, a possible side effect of the SGB procedure, is characterized by "a droopy eye, constricted pupil, and red eye on right-hand side," said Rae Olmsted.

"This was a concern, but one we couldn't control for. We had our clinicians and clinical staff tell everybody, regardless of treatment group, that it was potential outcome," she said.

The fact that the study population was highly specified might limit clinical generalizability, say the authors. Also, the overall severity level of PTSD symptoms in the sample was low to moderate, which might limit generalizability with respect to patients routinely seen in outpatient practice.

"However, we view inclusion of active-duty service members with subthreshold signs as a strength, given emerging evidence suggesting PTSD symptoms may be best seen as a continuum," the authors write.

The investigators are planning a large-scale, multisite cohort study that will follow PTSD patients for a year after they receive SGB. The researchers will assess factors such as symptom trajectory, the degree to which patients improve over time, and how long they remain better.

Questions Remain

Commenting on the findings for Medscape Medical News, Gary H. Wynn, MD, Col, MC, Uniformed Services University of the Health Sciences, and senior scientist, Center for the Study of Traumatic Stress, Bethesda Maryland, said the study was "well done."

These positive findings suggest that "SGB should be in the tool box for PTSD, but we're just not sure how best to use the tool yet," said Wynn.

"We have to figure out if we should we use it early in the process of treatment or later on in the process of treatment, in combination with psychotherapies or in combination with other medicines. Do you start off with this and wait until patients get some symptom relief and then initiate medicines?" he said.

Although questions still need to be answered about the treatment, Wynn said, "It's very clear from this study that there is some validity to its use."

He's concerned that people will interpret these positive results to mean that SGB is "curative," when "the truth is, this is a modest result."

He also pointed out that the procedure must be performed by an anesthesiologist who is very familiar with SGB. "So there are some limitations to the construct of this that suggest we're not going to roll this out to all 400,000 Veterans Affairs beneficiaries who have a diagnosis of PTSD."

Also commenting, retired military psychiatrist Elspeth Cameron Ritchie, MD, chief of psychiatry at Medstar Washington Hospital Center, Washington, DC, who has expertise in PTSD among combat veterans, said she's "really excited" by the findings.

This is the first study to show that the procedure works on a wide scale, said Ritchie, and that's "incredibly significant."

However, she pointed out that the treatment isn't effective for everyone. "One of the challenges is to determine who it works for," she said.

Ritchie agreed that study participants who developed Horner syndrome likely suspected that they had been given the active treatment. But she noted the difficulty of conducting a sham study that involves injecting an agent into the participants.

"No study is perfect, and the fact that they got as many people as they did into this one and that they showed a significant difference on the standardized measure is very exciting."

Ritchie said she and her colleagues "would love" to see this type of study carried out in a Veterans Administration setting in which there is a "very large population of potential subjects" with chronic conditions.

Rae Olmsted reports having a cooperative agreement for the funding of this study with the US Army during the conduct of the study. Wynn and Ritchie report no relevant financial relationships.

JAMA Psychiatry. Published online November 6, 2019. Abstract

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