Stellate Ganglion Block (SGB) Frequently Asked Questions

What are the risks of an SGB?

The overall risks of having a significant adverse event are very small (much less than 1 in 1000) when done by a skilled provider with ultrasound guidance. There is a very small risk of a seizure from inadvertently injecting the local anesthetic into a blood vessel. There is also a very small risk of forming a dangerous hematoma (collection of blood from a bleeding vessel). This risk is very small in people not taking blood thinning medications. SGB should not be done in people currently on blood thinning medications. About 20 percent of the time after a block, patients get a hoarse voice or feel like there is something in the back of their throat. This occurs when the anesthetic spreads to another nerve near the larynx. This is not a mistake or dangerous, it just happens sometimes. The hoarse voice or feeling in your throat, if it occurs, will wear off in 3-6 hours.

Why does Dr. Mulvaney perform the SBG only at the C6 level (sixth cervical vertebral level)?

The main reason is that there are NO published studies to support doing any other vertebral level, while there are over 18 peer-reviewed medial publications showing efficacy and safety when the SGB is done at the C6 level. Doing higher cervical levels introduces more risk without any published potential benefit.

Why is an ultrasound-guided SGB is more effective?

Ultrasound allows the needle to be safely guided around the nerves and blood vessels in the neck as it is placed next to the Stellate Ganglion. Under x-ray (fluoroscopic) guidance only bones are visible, and nerves are not visible at all, therefore position of the nerves can only be approximated. Using ultrasound guidance to safely perform an SGB takes special training and considerable skill which many pain medicine trained physicians do not have. Although during my fellowship in anesthesia/pain medicine at Walter Reed National Military Medical Center I learned to do SGBs with fluoroscopic-guidance, I rejected this method as being too painful for the patient, less efficacious and unnecessarily risky as it exposes patients to ionizing radiation of the xray, compared to ultrasound. Doesn’t it make sense that you should be able to actually see your target as well as avoiding major blood vessels and nerves?

How does Dr. Mulvaney evaluate if the SGB performed was successfully done?

I was the first person to publish a grading scale to evaluate and measure Horner’s syndrome which happens after a successful SGB. Horner’s syndrome is a series of temporary changes that happens on the side of the body that was blocked only once the “fight-or-flight” nervous system has been successfully turned off. Some of the changes are easily visible and includes ptosis (the eyelid will droop), miosis (the pupil will get smaller) and scleral icterus (the white part of the eye become red). I have another person grade and assign the resulting Horner’s syndrome a score to reduce bias. Although this is uncommon, if for some reason the Horner’s score is not adequate by 5 minutes after the SGB, I will then repeat the procedure on the same side to ENSURE you get the benefit of the SGB. This is a photo of a strong Horner’s syndrome.


What should I do if the initial SGB provided on the right side C6 does not provide the results that I had hoped for?

Although SGB has been demonstrated in the medical literature to provide durable relief of anxiety symptoms associated with PTSD, no therapy is 100% effective. A patient may have other medical conditions affecting their anxiety symptoms which may not respond to treatment with SGB. However, if they are a good candidate for this therapy, (PTSD diagnosis with an elevated PCL-5 score) and they fail to respond to a right-sided SGB, then the patient should consider a left-sided SGB. This must be done at least one day later for safety reasons. (Never have a block on both sides of the neck within a 24-hour period; in theory this could block an airway). Although the exact figure is not known at this time, about 1-5% of patients will not respond to a right-sided SGB but will respond profoundly to a left-sided SGB. Also, new unpublished data suggests that some people, perhaps as high as 20% of people, even if they partially respond to a right sided SGB, may have a more profound response to a left-sided SGB. This appears to be the case because some people have anatomic differences in how their “fight or flight” system is wired. If they fail to respond to a properly performed SGB with a good resulting Horner’s on the right and left side, then SGB is not an effective therapy for this patient and further SGBs should not be attempted.

What is the percentage of success?

We carefully screen our potential patients to select those that have the best chance of having success with the SGB. In a properly selected patient, we have a better than 85% success rate (defined by significant improvements in the PCL-5 score).

How many treatments does it usually take?

Many people are successfully treated with a single SGB and do not need another SGB. Some people may be exposed to conditions that “re-trigger” their PTSD symptoms and need another treatment in the future. It can be safely repeated if it was helpful the first time. Doing your follow up PCL-5 at one week and one month after your SGB is very important so we can document whether this was a good therapy for you in case you need an SGB again in the future.

How many of these blocks has Dr. Mulvaney done?

Over a 10-year period, Dr. Mulvaney has safely completed over 1000 ultrasound-guided SGBs and is one of the most experienced physicians in the world at this technique. He has taught hundreds of physicians neck sonographic anatomy and SGB technique. As a fellowship-trained and board-certified interventional pain physician, he is also proficient in fluoroscopically (x-ray) guided SGBs, but he strongly feels that the fluoroscope method is more painful, less accurate and unnecessarily exposes patients to ionizing radiation.

Do I need to be sedated?

No. Sedation actually significantly increases the risk of this procedure. I have done over 1000 SGBs and have never had to use sedation on a patient. This procedure is NOT painful. Most patients describe it as a 1/10 for pain. The environment in my clinic is calm, and I will talk you through everything. Even people who don’t like needles do very well during the procedure.

Are you treated in the same appointment as the screening?

Everyone is screened prior to being scheduled. No additional appointment is needed for screening.

Can I drive after the procedure?

The accepted medical practice is that you cannot drive for at least 4 hours after this procedure. Please plan to have a driver with you or use a driving service like Uber.

How does SGB work to help PTSD symptoms?

The Stellate Ganglion is part of the cervical sympathetic chain, a key part of the sympathetic nervous system, which is the “fight or flight” nervous system. In PTSD and some other anxiety conditions, the “fight or flight” nervous system gets stuck in the “ON” position. By precisely placing long-acting local anesthetic (ropivacaine) around the stellate ganglion, the unproductive and chronic “fight or flight” response is turned off for several hours. I and other researchers believe this allows neurotransmitters in the brain to “reset” back to a non-anxiety state. What we do know and can measure is this “resetting” results in long-term relief of anxiety symptoms.

Where is the closest airport?

Our office is located at 116 Defense Hwy Suite 203, Annapolis, Maryland 21401. Baltimore Washington International Airport (BWI) is the closest airport and is 25 minutes to the North. Reagan International airport is 50 minutes away, and involves traveling on the 495 Beltway, which may have heavy rush hour traffic. Dulles International Airport is approx 1.5 hours away and also subject to heavy traffic. Please click the below button to view the Annapolis travel guide to help plan for your visit.

For what symptoms do you use the SGB procedure to treat?

In my clinical practice and research, I have mostly used and published on using SGB to treat the anxiety symptoms associated with PTSD. I have also used it successfully to treat other anxiety conditions, vasomotor symptoms associated with menopausal hot flashes, as well as for helping reduce symptoms during treatment for opioid addiction.

What does SGB NOT treat?

SGB is not a treatment for Depression, Bipolar disorder, Schizophrenia or any variants of Schizophrenia, Personality Disorders or Seizure disorders. Traumatic Brain Injury (TBI) and PTSD symptoms can overlap. SGB may be helpful for treatment of TBI symptoms but this has not been proven. It can help the PTSD symptoms that may also be present.