Stellate ganglion block is an innovate procedure that can be used in the management of a variety of chronic pain conditions including CRPS, phantom pain, facial pain and postherpetic neuralgia. More recently it has been used in the management of post-traumatic stress disorder and hot flushes. Because the stellate ganglion is connected to brain regions thought to be abnormally activated in PTSD, such as the amygdala, SGB has been explored as a potential alternative treatment option for PTSD. Studies that have examined brain imaging before and after PTSD treatment provide potential evidence of this biological rationale for the effect of SGB on PTSD.
Ultrasound technique has added a new dimension to this procedure, making it very safe and accurate. 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 the position of the stellate ganglion can only be approximated.
It is important to note that in some cases injection treatment may not provide the desired results or the pain relief may not be sustained.
At Pain Spa Dr Krishna is very experienced in interventional treatments. Dr. Krishna always performs stellate ganglion block under ultrasound guidance, for greater accuracy and improved safety. Ultrasound provides the added advantage of visualizing the surrounding structures including muscles, nerves and blood vessels.
The stellate ganglion is part of the sympathetic nervous system that is located in your neck, on either side of your voice box. A stellate ganglion block is an injection of local anaesthetic around these nerves. We perform this injection under real-time ultrasound guidance. The sympathetic nervous system controls the “fight or flight” response and blocking this with local anaesthetic tends to dampen this system.
The Stellate Ganglion is part of the cervical sympathetic chain, which controls the “fight or flight” response. The specific mechanism of action by which SGB may mitigate PTSD symptoms remains incompletely understood. One of the proposed mechanisms is that the application of local anaesthetic to the stellate ganglion leads to a reduction in nerve growth factor and a resulting decrease in sympathetic nerve sprouting and brain norepinephrine levels.
In PTSD and some other anxiety conditions, the “fight or flight” nervous system remains permanently ‘ON’. By precisely placing long-acting local anaesthetic around the stellate ganglion, the unproductive and chronic “fight or flight” response is turned off for several hours. This allows neurotransmitters in the brain to “reset” back to a non-anxiety state. This “resetting” results in long-term relief of anxiety symptoms. The SGB may improve daily activities, sleep, relationships, mood, employment and more.
In this trial of active-duty service members with PTSD symptoms (at a clinical threshold and subthreshold), 2 SGB treatments 2 weeks apart were effective in reducing CAPS-5 total symptom severity scores over 8 weeks. The mild-moderate baseline level of PTSD symptom severity and short follow-up time limit the generalizability of these findings, but the study suggests that SGB merits further trials as a PTSD treatment adjunct.
Uncontrolled case series of predominantly males in their early forties who were active-duty military with combat-related PTSD (N=202) have found high rates of clinically meaningful improvement with SGB (70% to 75%), including in those with extreme PTSD. Case series can be valuable in providing an initial indication of promise. However, their lack of a control group is a major drawback that prevents drawing conclusions regarding treatment effects. For example, it is quite common to see very encouraging results in a few case series, followed by smaller benefits or contradictory findings in subsequent RCTs.
In a military population with multiple combat deployments, over 70% of the patients treated had a clinically significant improvement in their PCL score which persisted beyond 3 to 6 months postprocedure. Conclusion was that the selective blockade of the right cervical sympathetic chain at the C6 level is a safe and minimally invasive procedure that may provide durable relief from anxiety symptoms associated with PTSD.
Please note that though some of the recent studies have been promising, further large randomized control trials are needed to better understand the procedure and its lasting effects. At this stage, SGB should, at best, be considered an adjunct treatment for PTSD. The mainstay of treatment continues to be psychotherapy and antidepressants.
Ultrasound imaging (sonography) uses high-frequency sound waves to view inside the body. Ultrasound shows all the surrounding soft tissue structures including muscles, tendons, ligaments, and nerves, whereas x-rays show only the bones. Because ultrasound images are captured in real-time, they can also show the movement of the body’s internal organs as well as blood flowing through the blood vessels. Unlike X-ray imaging, there is no ionizing radiation exposure associated with ultrasound imaging. Under ultrasound guidance, the needle tip can be visualized real-time whilst being advanced close to the stellate ganglion. This is not possible under x-ray guidance.
Using ultrasound guidance to safely perform an SGB takes special training and considerable skill which many doctors do not have. Dr. Krishna is an expert in performing ultrasound-guided procedures and has successfully performed several SGBs using this technology.
There are several studies showing the efficacy and safety of SGB when it is performed at the C6 level. There are no studies to support injection at C3 level in humans, though there is some evidence from rat models supporting injection at the superior cervical sympathetic ganglion.
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 (a block on both sides of the neck within a 24-hour period 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.
We recommend only one treatment to start with. Many patients will respond successfully to a single SGB, though the duration of improvement is unknown. Some patients 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. Completing your follow up PCL-5 at one week and one month after your SGB will help us determine if SGB was an effective therapy.
Please note that in a recently published study in JAMA psych (Nov 2019) two injections were performed at two weeks interval. Hence we are open to discussion regarding a 2nd injection if the first injection does not work.
The cervical ganglia are identified as the superior, middle, intermediate, and inferior cervical sympathetic ganglia. In 80% of the population, the inferior cervical ganglia and the first thoracic ganglia fuse together to form the stellate ganglia. The inferior cervical ganglia when present as distinct structures are located on the transverse process of C7 vertebra. The first thoracic ganglia lie in the front of the neck of the first rib. When they are fused together, they form the stellate ganglia.
The stellate ganglion is oval in shape and measures 2.5 cm long, 1 cm wide and .5 cm thick and is usually located behind the subclavian artery in the front of the first rib.
All the sympathetic nerves that supply the head and neck and most of those that supply the upper extremity traverse through the stellate ganglion. Thus, stellate ganglion block produces a more complete sympathetic denervation to the head and neck structures.
Stellate ganglion block has been advocated for diagnostic, therapeutic and prognostic purposes for a variety of conditions, including:
Multiple approaches have been used to localize the stellate ganglia. These include blind technique, plain fluoroscopic guidance and use of ultrasound. Traditionally these blocks have been performed either by using surface landmarks or by using a fluoroscopy-guided technique. Computerized tomography (CT) and magnetic resonance imaging (MRI) approaches have been described, these techniques are not practical in daily clinical practice. Recently, however, there has been a growing interest in using an ultrasound-guided technique because of the many advantages that this technique might offer.
Ultrasound-guided SGB can improve the safety of the procedure by direct visualization of the related anatomical structures and, accordingly, the risk of vascular and soft tissue injury may be minimized. In addition, ultrasound guidance will allow direct monitoring of the spread of the injectate and hence may minimize complications such as recurrent laryngeal nerve (RLN) palsy and intrathecal, epidural or intravascular spread.
The procedure is usually done on an outpatient basis. Stellate ganglion block injection is performed under ultrasound guidance to ensure accuracy of needle placement. Patients need to be aware that the outcome of the procedure is variable and they may not receive the desired benefits. Similarly, they must be aware of the transient nature of the therapeutic benefits and that there may need repeat injections.
For pain procedures generally, a mixture of local anaesthetic and steroid is injected. However, for PTSD treatment only local anaesthetic is injected around the stellate ganglion. The local anaesthetic agent leads to a reduction in nerve growth factor and subsequently a decrease in sympathetic nerve sprouting and brain norepinephrine levels.
Complications are rare, particularly if the injections are performed using a precise needle-positioning technique. Possible complications include bruising, infection, hematoma, nerve injury and reaction to the injectate. Infection can be avoided with appropriate aseptic precautions. Severe allergic reactions to local anaesthetics are uncommon. These local reactions last for 24 to 48 hours and are relieved by the application of ice packs. Post-procedural flare-up of symptoms may occasionally occur and tend to settle with time.
It is important to know that stellate ganglion block can be associated with a number of serious complications as the stellate ganglion is located in close proximity to various vital structures. These complications include: