The Stellate Ganglion Block (SGB) is a minimally invasive medical procedure that has gained attention as a potential treatment for Post-Traumatic Stress Disorder (PTSD). Although traditionally used for pain conditions, the procedure involves injecting a local anesthetic near a cluster of nerves in the neck. This application for PTSD is considered off-label, but it aims to chemically interrupt a dysfunctional biological circuit. The goal of SGB is to temporarily quiet the overactive “fight or flight” response, allowing the nervous system to reset itself.
The Stellate Ganglion and Sympathetic Overdrive
The mechanism of SGB centers on the stellate ganglion, a collection of sympathetic nerve cell bodies located in the lower neck, typically near the C6 and C7 vertebrae. This ganglion is a component of the Sympathetic Nervous System (SNS), which activates the body’s defensive responses. The SNS controls involuntary functions like heart rate, blood pressure, and pupil dilation, preparing the body to confront a perceived threat.
In chronic PTSD, the sympathetic nervous system often becomes stuck in a state of continuous hyperactivity, commonly referred to as sympathetic overdrive or hyperarousal. This constant state of alert leads to persistent PTSD symptoms, such as hypervigilance, exaggerated startle response, and sleep disturbances. The stellate ganglion acts as a two-way conduit connecting the brain’s emotional centers, like the amygdala, to the peripheral nervous system.
By injecting a long-acting local anesthetic near the ganglion, the SGB temporarily interrupts the transmission of nerve impulses through this pathway. This short-term chemical blockade suppresses the excessive signaling that perpetuates the hyperarousal state. This interruption allows the brain’s circuits that control the “fight or flight” response to return to a more balanced state. One proposed theory suggests the block reduces levels of nerve growth factor, decreasing brain norepinephrine levels elevated in chronic stress.
Performing the Block: Procedure Details
The SGB procedure is performed in an outpatient setting, often by an anesthesiologist or interventional pain specialist. Historically, this procedure was guided by fluoroscopy (X-ray), but contemporary practice often utilizes ultrasound guidance, which allows for real-time visualization of the needle tip, surrounding blood vessels, and nerves.
The injection site is typically targeted near the C6 or C7 vertebral level in the neck, where the stellate ganglion is located. A small volume of local anesthetic, such as Ropivacaine or Bupivacaine, is injected near the nerve cluster. The entire process, from preparation to the injection itself, usually takes less than 15 to 30 minutes.
Following the injection, the patient is observed for a short period to monitor for immediate effects or complications. A successful block is often confirmed by the temporary onset of Horner’s syndrome on the same side of the injection. This expected, temporary effect includes a droopy eyelid, a constricted pupil, and nasal congestion, indicating the anesthetic has effectively spread.
Clinical Efficacy and Duration of Relief
The efficacy of SGB for PTSD has been addressed through a growing body of clinical research, though its use remains investigational for this condition. Early case series reported high rates of rapid clinical improvement, with estimates suggesting 70% to 83% of treated patients experienced significant positive outcomes. More recent randomized controlled trials have provided stronger evidence, demonstrating that SGB is effective in reducing the severity of PTSD symptoms.
Symptom relief often begins almost immediately or within hours of the procedure, which is an advantage over pharmacotherapy that can take weeks to become fully effective. The types of symptoms that commonly improve are those directly related to sympathetic overactivity. Many patients report a rapid decrease in their overall anxiety levels.
The duration of the therapeutic effect can vary significantly among individuals. While the local anesthetic wears off within hours, the sustained relief from PTSD symptoms can last for weeks to many months. If symptoms begin to return, some patients may require a second injection to achieve a more lasting effect. The long-term benefit is thought to be a result of the nervous system maintaining the “reset” state achieved during the period of chemical blockade.
Patient Suitability and Safety Profile
SGB is primarily considered for individuals who have not found adequate relief from conventional first-line treatments, such as trauma-focused psychotherapy and pharmacotherapy. Patients with treatment-refractory symptoms are typically the most appropriate candidates for this procedure. It is often recommended as an adjunctive therapy to supplement ongoing talk therapy or medication.
The procedure is generally considered safe, but like any injection, it carries risks. Expected and temporary side effects are common, including hoarseness due to the proximity of the recurrent laryngeal nerve, a feeling of a lump in the throat, and Horner’s syndrome. These effects typically resolve completely within four to six hours as the local anesthetic wears off.
Serious complications are rare but can include infection at the injection site, bleeding, or the inadvertent puncture of nearby structures. These structures include the esophagus, the thyroid gland, or major blood vessels, which could lead to nerve damage or vascular complications. A thorough medical evaluation and the use of precise image guidance minimize these potential serious risks.