# stellate ganglion block | Symptoms, Causes, Tests and Treatment | OSANG > A stellate ganglion block is a procedure that temporarily blocks sympathetic nerve activity by injecting a local anesthetic into the sympathetic ganglion at the front of… - Official page: https://osns.co.kr/en/encyclopedia/stellate-ganglion-block - Organization: OSANG Neurosurgery ## Page content Neuromodulation ## stellate ganglion block Stellate Ganglion Block Stellate ganglion block (SGB) is a neuromodulation procedure that temporarily blocks sympathetic nerve transmission to the head, neck, and upper extremities by injecting local anesthetic into the stellate ganglion located in the lower neck (C7~T1). ## At a glance A stellate ganglion block is a procedure that temporarily blocks sympathetic nerve activity by injecting a local anesthetic into the sympathetic ganglion at the front of the neck. When the sympathetic nerves to the head, face, neck, and arms are blocked, blood flow to those areas increases and pain signal transmission is inhibited. It is applied to complex regional pain syndrome (CRPS), autonomic dysfunction, headache, upper extremity blood flow disorder, and post-traumatic stress disorder (PTSD). It is performed under ultrasound guidance, the procedure takes about 10 to 15 minutes, and can be performed on the same day in an outpatient setting. After the procedure, temporary drooping of the eyelids and narrowing of the pupil (Horner syndrome) appear, indicating that the block has been successfully achieved. - 01Definition and Overview - 02anatomy - 03Indications - 04Treatment method - 05Mechanism of Action - 06Effect and evidence - 07Side effects and precautions - 08Post-procedure care ## Definition and Overview Stellate ganglion block (SGB) is a neuromodulation procedure that temporarily blocks sympathetic nerve transmission to the head, face, neck, and upper extremities by injecting a local anesthetic into the stellate ganglion, which is the cervical sympathetic ganglion. The history of stellate ganglion block goes back to the 1920s. Since Leriche and Fontaine applied cervical sympathetic nerve blockade to treat upper extremity blood flow disorders in 1934, it has been widely used in the field of pain treatment. Since then, the scope of adaptation has expanded to include complex regional pain syndrome (CRPS), headaches, facial flushing, and hyperhidrosis, and since the 2000s, it has been receiving new attention as its treatment effect for post-traumatic stress disorder (PTSD) has been reported. With the development of ultrasound guidance technology, the accuracy and safety of the procedure have been greatly improved. Compared to the existing blind technique, ultrasound-guided procedures significantly lowered the rate of complications such as vascular puncture. ## anatomy The stellate ganglion is a star-shaped ganglion formed by the fusion of the inferior cervical ganglion and the first thoracic ganglion. In about 80% of the population, these two ganglia are fused, and in the remaining 20%, they exist separately. The stellate ganglion is located in front of the vertebral body, between the front of the transverse process of the C7 vertebra and the neck of the first rib. It lies on the longus colli muscle, and is adjacent to the subclavian artery and vertebral artery anteriorly. Because of this anatomical relationship, precise image guidance is essential to prevent blood vessel damage during the procedure. Postganglionic sympathetic fibers from the stellate ganglion are distributed to the following areas: - Head and face: dilator pupillae muscle, Müller muscle, facial blood vessels, sweat glands - Cervical: thyroid, carotid artery, pharynx, larynx - Upper extremities: blood vessels and sweat glands in the arms and hands - Heart: Part of the sympathetic nerve fibers involved in heart rate and conduction For this reason, when the stellate ganglion is blocked, signs of widespread sympathetic nerve blockade appear, such as increased blood flow to the ipsilateral face and upper extremities, decreased sweating, and constricted pupils. ## Indications Stellate ganglion blockade is applied to a variety of diseases involving hyperactivity of the sympathetic nerves. ### pain disease - Complex regional pain syndrome (CRPS): This is the most common indication for SGB. When SGB was performed in CRPS type I patients, pain reduction and functional improvement were reported in approximately 70-80% of patients. The treatment response rate is high when administered early. - Postherpetic neuralgia: Studies have shown that early SGB treatment for acute stage shingles can reduce the progression to postherpetic neuralgia. - Phantom limb pain: Applies to phantom limb pain that occurs after upper limb amputation. - Trigeminal neuralgia and facial pain: Used as an adjunctive treatment for facial neuralgia that does not respond to drug treatment. ### autonomic dysfunction - It is applied to symptoms such as palpitations, abnormal sweating, anxiety, and insomnia caused by sympathetic nerve overactivity. - Relieves sympathetic hyperactivity by resetting autonomic balance. ### headaches and migraines - Cluster headache: Used for the acute treatment of cluster headaches involving sympathetic dysregulation. - Cervicogenic headache: Applies to headaches involving hyperactivity of the cervical sympathetic nerves. ### blood flow disorders - Raynaud phenomenon: SGB is effective in improving blood flow in a disease in which fingers turn pale and pain occurs due to constriction of blood vessels in the upper limbs due to sympathetic nerve overactivity. - Upper extremity thromboembolism: Used as adjunctive treatment for acute upper extremity blood flow disorders. ### Post Traumatic Stress Disorder (PTSD) In a study by Lipov et al., it was reported that the PTSD symptom scale (PCL, PTSD Checklist) score decreased by more than 20 points on average after SGB was implemented, and this effect lasted for several months. In a double-blind cross-controlled study conducted by Hanling et al. in 2016, the SGB group showed significant improvement in PTSD symptoms compared to the placebo group. This effect is presumed to be due to a mechanism in which sympathetic nerve blockade suppresses hyperactivity of the amygdala and reduces norepinephrine secretion. ### Other - Hot flashes: Effectiveness has been reported for hot flashes following menopause or breast cancer treatment. - Hyperhidrosis: Applies to excessive sweating of the upper extremities and face. - Acute hearing loss: There are cases where it has been used as an adjuvant treatment to improve blood flow to the inner ear. ## Treatment method Currently, the standard for stellate ganglion block is performed under ultrasound guidance. ### Preparation before procedure - The patient is in the supine position and slightly extends the neck. - The skin at the treatment area is disinfected and an ultrasound probe is placed on the neck. - On ultrasound images, major structures such as the C6 or C7 transverse process, longus colli muscle, carotid artery, internal jugular vein, and thyroid gland are identified. ### Procedure 1. Using ultrasound, the anatomical structure and blood vessels around the stellate ganglion are checked in real time. 2. A small amount of local anesthetic is applied to the skin. 3. A 25-27 gauge needle is introduced under ultrasound guidance into the surface of the longus colli muscle and the subfascial space where the stellate ganglion is located. 4. An aspiration test confirms that it has not entered the blood vessel. 5. Slowly inject 5 to 10 mL of 0.25% bupivacaine or 1% lidocaine. 6. Ultrasound imaging confirms the spread of the drug around the stellate ganglion. The total procedure time is approximately 10 to 15 minutes, and patients are observed for 30 minutes to 1 hour after the procedure before returning home. ### Advantages of Ultrasound Guidance Ultrasound-guided procedures have several advantages over the landmark-based technique used before the 1990s. Since the position of the needle tip can be confirmed in real time, the risk of complications such as vascular puncture, esophageal damage, and pneumothorax is significantly reduced. According to a study by Nader et al., the volume of local anesthetic required for ultrasound-guided SGB was half that of the conventional method (5 mL vs. 10~20mL), lowering the risk of systemic toxicity. ## Mechanism of Action The therapeutic effect of stellate ganglion blockade is expressed through multi-layered mechanisms. ### Blockade of sympathetic nerves and increased blood flow When a local anesthetic blocks the cell bodies of sympathetic nerves in the stellate ganglion and the sodium channels of nerve fibers, vasoconstrictor signals in the area controlled by the nerve are suppressed. As a result, blood vessels in the head, face, and upper extremities dilate and blood flow increases. This effect serves as the basis for the treatment of Raynaud's phenomenon or upper extremity blood flow disorders. ### pain inhibition pathway Abnormal coupling between sympathetic and sensory nerves is a key mechanism of sympathetically maintained pain. SGB blocks this abnormal connection, breaking the vicious cycle of pain mediated by the sympathetic nerves. This is the main reason why SGB is effective in CRPS. ### Autonomic nerve reset effect Although the pharmacological blocking effect of SGB lasts only a few hours, improvement in clinical symptoms often lasts for several days to several weeks. This is explained because the overactive state of the sympathetic nervous system goes through a kind of 'reset' and returns to the normal sympathetic-parasympathetic balance. Lipov et al. proposed this as the “sympathetic reboot” hypothesis. ### central nervous system effects Recent studies have reported that SGB affects not only the peripheral sympathetic nervous system but also the central nervous system. It was confirmed that amygdala hyperactivity decreased and brain norepinephrine concentration decreased after SGB was implemented. This explains the mechanism by which SGB is effective in PTSD and suggests that peripheral sympathetic nerve blockade also has a bottom-up modulation effect on central autonomic nervous system regulation. ## Effect and evidence ### Complex Regional Pain Syndrome (CRPS) CRPS is the best-established indication for SGB. In a study by Ackerman and Zhang, when a series of SGBs were performed on patients with CRPS type I, significant pain reduction (VAS reduction of more than 50%) was observed in approximately 72% of patients. The response rate was higher in the early treatment group where SGB was performed within 6 months of onset. Lipov et al. (2009) reported that the PTSD symptom scale score decreased by an average of 21 points (PCL-M standard) after SGB was implemented, and that the effect lasted for more than 6 months in some patients. Lynch et al. (2016) confirmed significant improvement across PTSD symptom clusters (re-experiencing, hyperarousal, and avoidance) after implementing SGB in a study targeting 166 active-duty soldiers. Hanling et al. (2016), in a double-blind randomized controlled trial, the SGB group showed a significant decrease in CAPS (Clinician-Administered PTSD Scale) score compared to the placebo group. ### Effect onset and continuation The sympathetic nerve blocking effect of SGB appears within minutes immediately after the procedure and is confirmed by the development of Horner syndrome. The pharmacological blockade time is 2 to 4 hours for lidocaine and 6 to 12 hours for bupivacaine, depending on the drug used. However, improvement in clinical symptoms is observed to persist for several days to several weeks even after the drug's effect is lost, and it has been reported that the duration of the effect gradually extends with repeated treatments. ## Side effects and precautions ### Normal response (signs of sympathetic blockade) The following signs on the surgical side after performing SGB are normal reactions indicating successful blockade. - Horner syndrome: Mydriasis (miosis), drooping of the eyelids (ptosis), and enophthalmos (invaginations) appear on the ipsilateral side. It is observed in approximately 90-95% of patients who undergo SGB, and disappears spontaneously with the loss of drug effect. - Conjunctival hyperemia: Congestion occurs due to dilatation of blood vessels in the eye on the treated side. - Nasal congestion: Due to vasodilatation of the ipsilateral nasal mucosa. - Facial anhidrosis: No sweating on the face on the side of the treatment. - Increased upper extremity temperature: The skin temperature of the hand on the side of the treatment increases by 1 to 3 degrees. ### temporary side effects - Voice changes (hoarseness): If local anesthetic spreads to the recurrent laryngeal nerve, your voice may temporarily change. Most people recover within a few hours. - Foreign body sensation and difficulty swallowing: If the anesthetic spreads to the nerves around the pharynx, a foreign body sensation may be felt in the throat or swallowing may be uncomfortable. - Paresthesia in the upper extremities: If some of the anesthetic spreads to the brachial plexus, numbness or weakness in the arm may appear temporarily. ### rare complications - Vascular damage: Puncture of adjacent blood vessels such as the carotid artery, internal jugular vein, and vertebral artery may occur. When performed under ultrasound guidance, the incidence of vascular puncture is reduced to less than 1%. - Pneumothorax: This can occur when the needle enters the pleura, but is extremely rare with ultrasound guidance. - Epidural or subarachnoid injection: This can occur when the needle enters excessively inside. This can be prevented by checking the position of the needle in real time using ultrasound. - Local anesthetic systemic toxicity: Occurs upon intravascular injection and is prevented by aspiration testing and appropriate dosage. ### Contraindications - Treatment site infection - On anticoagulants (increased risk of bleeding) - Recent myocardial infarction - Simultaneous treatment on both sides (if both sides are blocked simultaneously, there is a risk of breathing difficulties due to bilateral recurrent laryngeal nerve paralysis) - Glaucoma (changes in intraocular pressure due to narrowing of the pupil) ## Post-procedure care Immediately after the procedure, vital signs are observed at rest for 30 minutes to 1 hour. The success of the blockade is determined by confirming the occurrence of Horner syndrome. Recommendations on the day of the procedure are as follows: - Be careful not to eat or drink for 2 to 3 hours after the procedure (possibility of reduced sensation in the pharynx). - Avoid strenuous exercise and heavy lifting. - Avoid drinking alcohol. - Do not drive until symptoms in the eye treated have fully recovered. - Bruising or swelling may appear at the treatment site and usually disappears within 2 to 3 days. From the next day, you can return to your daily activities without any restrictions. The effect of the treatment and the presence of any abnormal symptoms are recorded and used to adjust the treatment plan during the next treatment. The interval between repeat treatments is determined depending on the disease and response to treatment, and is generally performed at intervals of 1 to 2 times a week. After repeating the treatment 3 to 6 times, the treatment response is comprehensively evaluated to determine whether additional treatment is necessary. ## Frequently asked questions ### Q01What kind of procedure is stellate ganglion block? This is a procedure that temporarily blocks the activity of the sympathetic nerves by injecting a local anesthetic into the sympathetic nerve mass called the stellate ganglion located in the front of the neck. It is used to relieve various symptoms caused by excessive stimulation of the sympathetic nervous system. It is a relatively simple procedure that requires one injection, and can be performed on the same day as an outpatient. ### Q02Does it hurt a lot during the procedure? Because local anesthesia is applied to the treatment area first, you will not feel any severe pain. When the drug is injected, there may be a slight feeling of pressure or stiffness around the neck, but this is easily tolerated by most patients. It is performed safely because the needle position is checked in real time using ultrasound. ### Q03How quickly do the effects of the treatment appear? Immediately after the procedure, you will notice slight drooping of the eyelid on the treated side, bloodshot eyes, and warm hands. These changes are a sign that the sympathetic nerve blockade has been successfully achieved. Some people feel improvement in pain or autonomic symptoms from the day of the procedure, while others gradually improve after repeated procedures. ### Q04How long do the effects last? The pharmacological blocking effect of local anesthetics lasts from several hours to a day. However, as the hyperactivity of the sympathetic nervous system is reset, symptom improvement often continues for several days to several weeks even after the anesthetic effect wears off. It is observed that the duration of effect gradually increases with repeated treatments. We adjust the treatment interval and number of treatments depending on the patient’s condition. ### Q05How many treatments should I have? It varies depending on the disease and symptoms. In some cases, 1 to 2 times is sufficient for acute pain or blood flow disorders, and for chronic autonomic dysfunction or CRPS, it is common to repeat the procedure 3 to 6 times at intervals of 1 to 2 times a week. We will check the response to the treatment and develop a treatment plan tailored to the patient. ### Q06Are there any side effects or risks? After the procedure, drooping eyelids, narrowing of the pupil, and nasal congestion on the treated side may appear temporarily. This is a normal reaction to blocking the sympathetic nerve and will naturally recover within a few hours. Your voice may be temporarily hoarse or you may feel a foreign body sensation, but it will return on its own. When performed under ultrasound guidance, the risk of serious complications such as vascular damage or pneumothorax is very low. Although it is a safe procedure, we provide thorough explanation before the procedure. ### Q07Is it possible to return to daily life immediately after the procedure? On the day of the procedure, you can rest for 30 minutes to 1 hour before returning home. Avoid strenuous exercise or lifting heavy objects that day, and refrain from drinking alcohol. From the next day, there are no special restrictions on daily activities. It is safe to drive after symptoms in the treated eye have completely recovered. ## Related articles - Transcranial magnetic stimulation - Transcranial Direct Current Stimulation - Transcutaneous vagus nerve stimulation - Radiofrequency nerve block This article provides general medical information and does not replace an individual diagnosis or treatment plan. 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