A nearly century-old anesthesia technique is showing promise as treatment for post-traumatic stress disorder, relieving symptoms in 70 percent of combat veterans who received it once or more, according to a new review.

The therapy, stellate ganglion block, or SGB, quelled symptoms of PTSD, such as sleep disturbances, anxiety and depression, as measured by a checklist in nearly 100 service members suffering from combat-related stress within a week of treatment, according to the report published in October.

SGB involves injecting an anesthetic into a bundle of nerves — the stellate ganglion — that sits near the base of the neck.

In some cases, the shot, given under general anesthesia and guided to the exact spot by a physician using an ultrasound, gave instantaneous relief to patients with chronic PTSD symptoms, according to the review of cases published in the journal Military Medicine.

"Among patients with one-week followup (after injection), 78.6 percent of responders had an average reduction of their PTSD checklist score" of 22 points, the study noted.

First developed to address shoulder, neck and face pain caused by the Herpes Zoster (shingles) virus and complex regional pain syndrome, SGB has been used to treat PTSD since 2008, initially tested by Dr. Eugene Lipov, a Chicago-area pain management specialist.

Lipov, who uses the nerve block to treat patients for facial and neck pain, knew SGB relieves menopause-related hot flashes and theorized that because it seems to "reboot" the body's temperature-regulating mechanism, it might reset a PTSD patient's overreaction to stimulus — their "fight or flight" response — by interrupting connections between the sympathetic nervous system and central nervous system.

"This was not something I just stumbled on. As a pain management specialist, I knew SGB relieved problems related to the sympathetic nerve system and thought it could work to relieve the hyperarousal characteristic of PTSD," Lipov said.

SGB has been studied by physicians at Naval Medical Center San Diego as a potential PTSD treatment and was found to improve symptoms in patients who had not benefited from the standard therapy of medication and psychological therapy.

But the procedure is not widely accepted as a potential therapy for PTSD.

One issue, Lipov said, is that PTSD remains a largely unexplained condition. It's characterized as a psychiatric disorder, but ongoing research points to a close relation to concussion or head injury or other physiological change in the brain that may contribute to PTSD development.

Physicians are reluctant to embrace SGB because they don't understand why a physical treatment could relieve what is categorized as a mental health disorder.

Also, Lipov and other advocates say, since the mechanism for how it works is not well understood — and since no advanced clinical trials have been done to determine its effectiveness — many providers shy away from it.

"We hear often that no one understands the mechanism for how it works, so they won't try it. But we don't really know the mechanisms for most medical procedures," San Diego-based consultant Dr. Maryam Navaie said. "Pharmacotherapy and psychotherapy are only moderately helpful, at best. We need more effective treatment options."

An SGB treatment lasts less than an hour for patients, who in most cases are sedated. According to Navy researcher Capt. Anita Hickey, the complication rate is rare, 1.7 per 1,000 procedures.

Aviation Structural Mechanic 1st Class Christopher Carlson retired from the Navy in 2010 after multiple deployments, including two tours In Iraq, and was diagnosed with PTSD after "having all sorts of nightmares, drinking, being depressed" and becoming paranoid, "shutting all the blinds in the house," he said.

He sought treatment at the Veterans Affairs Department but was not comfortable in group therapy, and the medications he was given did not seem to be effective.

After he learned about SGB from an acquaintance, he called Lipov.

"I woke up and I couldn't believe it. I felt so much better. The euphoria lasted for a while," he said.

Eventually some of his symptoms returned, so he received a second treatment and has felt better ever since.

"It's hard to put in words how much it's done for me. If I hadn't gotten this treatment, I would be either drunk right now or dead," he said.

To date, Lipov has treated 40 military or veteran patients with PTSD, he said, largely financing the $1,000 cost per treatment through donations or out of his own pocket.

The patients have paid for little besides a hotel room in Chicago for appointments, he said.

According to a new VA study of 60,000 post-9/11 veterans, 13.5 percent screened positive for PTSD.

Another VA-funded study, the National Vietnam Veterans Longitudinal Study, estimated the prevalence of PTSD in combat Vietnam veterans at slightly more than 11 percent, even 40 years after the war.

Currently accepted treatments for PTSD at VA include medications, including two drugs approved by the FDA for PTSD — Paxil and Zoloft — and prolonged exposure therapy and cognitive processing therapy.

But studies show these treatments are effective in fewer than half of patients with combat-related PTSD.

Retired Army Col. Elspeth Ritchie, a psychiatrist with the Washington, D.C., Behavioral Health Department, says more research is needed on alternative therapies to improve outcomes for troops with war-related psychiatric conditions.

"I'm a big proponent of alternative therapies as a bridging therapy, therapies like acupuncture, stellate ganglion block, yoga, dog therapy. We don't know why but we need to support research to determine whether they can work on individuals."

Another Lipov patient — a former Marine counterintelligence staff sergeant who served from 1997 to 2004 — said he spent years bouncing among counselors, trying different medications to see if anything would help.

A neighbor told him about stellate ganglion block, so he spent about a year researching it.

"One of the hardest things about PTS is you keep thinking you are going to beat it on your own, so you drag your feet. But eventually, I needed to do something," he said.

The former Marine received his first shot in October.

"I went out that night in Chicago and felt at ease, and that night, I slept better than I had in 10 years. Now I can concentrate. I definitely recommend it," said the former Marine, now a narcotics investigator for a local law enforcement agency in Tennessee.

VA has studied SGB as a potential treatment; in October, researchers from the Long Beach Veterans Affairs Healthcare System, California, published the results of their treatment of 12 troops.

The group found that SGB was greatly effective in helping the 12 patients, with five feeling better afterward and four described as "miracle cures," meaning they felt completely normal immediately after the treatment.

While some of the effects waned for a few of the veterans a month after treatment, they were eligible for additional SGB treatments.

"We now use this as a special tool to help patients for whom nothing else works," Dr, Michael Alkire told Medscape Medical News on Oct. 13.