Historical Evolution The stellate ganglion block (SGB) is a minimally invasive treatment commonly used in pain clinics, which involves injecting local anesthetic into the loose connective tissue containing the stellate ganglion to achieve a reversible block of the cervical sympathetic trunk, cervical sympathetic ganglion with the preganglionic and postganglionic nerves and their innervated range. The method was originally discovered by accident when Liverpool and Alexander, while ligating the vertebral artery in 1883 to treat cancer, accidentally injured the sympathetic nerve, but obtained unexpected therapeutic results. For many years thereafter it was treated by surgical severance of the cervical sympathetic nerve, and in 1920 minimally invasive percutaneous stellate ganglion block therapy was introduced. The SGB is now a widely used clinical treatment, not only for painful disorders of the head, neck, chest and upper extremities in the area it innervates, but also for cardiovascular, cerebrovascular and vegetative nervous system disorders throughout the body. Anatomical localization The cervical sympathetic ganglia are located posterior to the vascular sheaths of the neck and anterior to the transverse processes of the cervical spine, and generally have three sympathetic ganglia on each side called the superior cervical ganglion, the middle cervical ganglion, and the inferior cervical ganglion. The inferior cervical ganglion, also known as the stellate ganglion or cervicothoracic ganglion, is irregularly shaped, larger than the middle cervical ganglion, and located anteriorly between the base of the C7 transverse process and the neck of the first rib, posterior to the vertebral artery, and medial to the oblique muscle group, with the pulmonary apex below it. The stellate ganglion is oval in shape measuring approximately 2 cm in length and 1 cm in width. the inferior border of the stellate ganglion is located posterior to the pleura and is surrounded by loose foveal and adipose tissue. In addition, the stellate ganglion also emanates gray traffic branches, connecting the seventh and eighth cervical nerves and the first thoracic nerve, and branches around the subclavian artery and its branches forming a plexus that follows it to the first segment of the axillary artery. Other branches of this node form a vertebral artery plexus around the vertebral artery, respectively, and travel up the vertebral artery. It enters the cranial cavity, surrounds the vertebral artery and the basilar artery, and reaches the posterior cerebral artery, where it joins the plexus that originates from the internal carotid artery. The subcardiac nerve from the stellate ganglion descends along the posterior aspect of the subclavian artery, anterior to the trachea, and joins the cardiac plexus to participate in the activity of the heart. Rationale for the action The action of the stellate ganglion block involves the autonomic, endocrine and immune systems and has a regulatory effect on the function of these systems. This block helps to maintain the stability of the body’s internal environment and allows the correction of many autonomic disorders. By blocking the stellate ganglion, the excessive tension and hyperfunction of the stellate ganglion are relieved, causing vasodilatation of the head, neck, upper limbs and heart, significantly improving the blood flow to the heart and brain, enhancing the anti-disease function and anti-inflammatory effect of the body, regulating the endocrine system and stabilizing the systemic autonomic nervous system. Therapeutic effects 1. Inhibition of pain When patients have pain symptoms, sympathetic excitation can cause sensitivity and excitation of primary sensory neurons, and the level of norepinephrine (NE), which reflects sympathetic activity, rises in plasma. After sympathetic ganglion block, the function of its preganglionic and postganglionic fibers is inhibited, which can block the cremaster reflex pathway, reduce the release of substance P and plasma catecholamines in the cremaster, decrease sympathetic excitability, inhibit vasoconstriction, glandular secretion and myotonia in its distribution area, improve local tissue ischemia, hypoxia and metabolic abnormalities, and increase local blood circulation to carry away the pain-inducing inflammatory mediators, thus The vicious cycle of “pain – sympathetic motor nerve excitation – local ischemia and hypoxia – pain” can be interrupted. The important innervation of the heart mainly comes from the stellate ganglion, but there is an asymmetry in this innervation, the left and right side of the stellate ganglion block has different effects on the sinus node, cardiac conduction and myocardial inactivity, and even shows the opposite effect. The right sympathetic ganglion block has a more pronounced effect on heart rate than the left, but there is disagreement about the cardiovascular modulatory effects of unilateral blockade. Kim et al. found that a left stellate ganglion block increased cardiac vagal tone in patients with head and neck pain, whereas a right block did not. Stellate ganglion blocks dilate blood vessels and increase hemodynamic stability. Early experiments have demonstrated that blocking the stellate ganglion produces vasodilating and hemodynamic effects similar to those of prostaglandin E (PGE1) infusion. Stellate ganglion blockade can regulate the function of cerebrovascular motor nerves, release vasospasm, increase cerebral blood flow velocity to improve neurological function, and significantly increase cerebral blood flow. Therefore, stellate ganglion block has a better therapeutic effect on cerebrovascular accidents and other brain diseases. 3, the effect on the endocrine system and stress response When the body is stimulated by ischemia and other stimuli can produce stress response, stress through the cerebral cortex, the limbic system of the brain to stimulate the hypothalamus autonomic nerves, through the sympathetic nervous system excitation conduction can lead to a series of pathological processes occurring in the body. Stellate ganglion block increases blood flow to the hypothalamus and can play a role in maintaining pituitary hormone homeostasis, corresponding to the sympathetic-induced response. By affecting the endocrine system of the hypothalamus and regulating different stress hormones, stellate ganglion blocks can reduce the adverse pituitary-adrenocortical stress response. Clinical application of stellate ganglion block There are various approaches to stellate ganglion block, mainly anterolateral approach, high lateral approach and auxiliary guided puncture method, among which anterolateral approach is most commonly used. The sign of successful block is the appearance of Horner’s syndrome on the injection side, which is characterized by pupillary constriction, eyelid ptosis, ophthalmoplegia, nasal congestion, conjunctival congestion, slight redness of the face, and absence of sweating. 1. Anterolateral approach (1) Paratracheal approach: The patient lies supine with a pillow under the shoulder. The operator is located on the left side and uses the index and middle fingers of the left hand to push the common carotid artery and sternocleidomastoid muscle to the lateral side. In the paratracheal and sternocleidomastoid muscle anterior edge of the sternoclavicular joint above about two transverse fingers (cricoid cartilage plane equivalent to C6 transverse process) with a 6.5-gauge needle and skin vertical needle, general patients with the tip of the index finger can touch the C7 transverse process, guide the needle, about 2-3 cm puncture, can touch the bone, indicating that the tip of the needle has reached the anterolateral side of the C7 transverse process, retreat the needle a little, back aspiration without blood, gas, brain crest fluid can be injected. It should be noted that there is no foreign sensation when puncturing the stellate ganglion, so it is not necessary to look for foreign sensation. This method was used more often in the early stage, but because the C7 transverse process is not easily accessible and close to the pleural apex, the probability of pneumothorax is higher and the vertebral artery is easily damaged, so it is less used now. (2) Modified paratracheal approach: the patient is placed in a supine position with a thin pillow on the head, and the operator’s index finger (in the case of left-sided block) or middle finger (in the case of right-sided block) is placed at two transverse (index and middle) fingers on the affected sternoclavicular joint, and the left middle finger or left index finger (the tips of the index and middle fingers are at the same level) is placed about 1 cm away from the left index finger or left middle finger, and the sternocleidomastoid muscle and its deep jugular arteriovenous sheath are pushed outward to separate from the trachea. When the tail of the needle is at the same level as the skin surface in front of the trachea (about 1.5-2.5 cm), there is no need to touch the keratin, and the drug can be injected without blood, gas, or brain crest fluid in the retraction. In recent years, it has been proposed that puncture at C6 and C7 sites has similar blocking effects on the stellate ganglion, and the former has significantly fewer complications than the latter. 2. High lateral entry puncture method The patient lies supine with the head turned to the opposite side and the skin is routinely disinfected. The operator is located on the left side, and the puncture point is the junction between the posterior border of the sternocleidomastoid muscle and the external jugular vein, which corresponds to the level of the cricoid cartilage or C6 transverse process. The puncture needle is entered vertically with the skin, so that the needle touches the C6 transverse process, then the needle is withdrawn a little, and the tail of the needle is then tilted at 45° to the head end, and the tip of the needle passes in the anterior side of the C6 transverse process, and the super advances about 1 cm in the direction of the C7 transverse process, and the back aspiration is free of blood and cerebral crest fluid can be injected. 3, auxiliary guidance puncture method The stellate ganglion is located in the vertebral artery triangle, in front between the base of the C7 transverse process and the neck of the first rib, surrounded by many important structures such as trachea, carotid artery, jugular vein, vertebral artery, recurrent laryngeal nerve, pleural cavity and other adjacent organs. The traditional blind puncture is difficult to locate, has low accuracy, and is prone to damage the cervical vessels and nerves, so the operation is risky. At present, the use of ultrasound for stellate ganglion block is becoming more and more common. Ultrasound has the advantages of easy portability, simple and easy operation, no radiological damage, etc. Moreover, compared with the traditional blind invasive operation, it has the advantages of correct selection of puncture point, shortening puncture time, precise control of needle depth, improving the success rate of puncture, avoiding blind puncture damage to adjacent important organs, especially for obese, short neck, pediatric, edema, hypotension It is especially superior to blind puncture for patients with obesity, short neck, pediatric patients, edema, hypotension, and deformities, which are more difficult to puncture. The application of ultrasound for ganglion block can both improve the success rate and reduce complications, and has a good prospect of application. Indications 1. Systemic diseases: phytodysfunction, primary hypertension/hypotension, hyper/hypoparathyroidism, anorexia, hyperphagia, postural blood pressure abnormalities, insomnia, generalized hyperhidrosis, vertigo, generalized leukodystrophy, skin itching, seborrheic dermatitis, post-stroke pain, multiple sclerosis, myasthenia gravis, herpes zoster, herpes simplex, infectious mononucleosis Chronic fatigue syndrome, reflex sympathetic dystrophy, phantom limb pain, amputation pain, diabetes mellitus. 2.Head disorders: demodicosis, headache (including migraine, tension headache, cluster headache, temporal arteritis headache), cerebral thrombosis, cerebral vascular spasm, cerebral infarction, etc. 3.Facial disorders: peripheral facial nerve palsy, atypical facial pain, masticatory muscle syndrome, mandibular joint syndrome. 4.Ocular diseases: retinal vascular occlusion, retinitis pigmentosa, uveitis, optic neuritis, cystoid macular swelling, corneal ulcer, cataract, pupillary strain, mosquito flying, visual fatigue, refractive abnormalities. 5.Ear, nose and throat diseases: chronic paranasal sinusitis, acute paranasal sinusitis, allergic rhinitis, sudden hard of hearing, exudative otitis media, Meniere’s disease, benign episodic vertigo, nasal congestion, tonsillitis, tinnitus, pharyngeal sensory abnormalities, olfactory disorders. 6, oral disorders: post-extraction pain, tongue pain, endostomatitis, tongue inflammation, labyrinthitis, intraoral mucosal dryness. 7, neck and shoulder and upper limb disorders: upper limb blood circulation disorders (such as Raynaud’s disease, Raynaud’s syndrome, acute arterial occlusive disease, neck-shoulder-arm syndrome, traumatic neck syndrome, thoracic outlet syndrome, shoulder periarthritis, post-operative swelling, post-mastectomy syndrome) tennis elbow, tenosynovitis, cervical spondylosis, arthritis, palmar hyperhidrosis, frostbite, frostbite, periarthritis, longitudinal nail fracture, axillary odor. 8, circulatory system diseases: myocardial infarction, angina pectoris, sinus tachycardia, cardiac neurosis. 9.Whistling system diseases: chronic bronchitis, pulmonary embolism, pulmonary edema, hyperventilation syndrome, bronchial asthma. 9.Whistling system diseases: chronic bronchitis, pulmonary embolism, pulmonary edema, hyperventilation syndrome, bronchial asthma. 11.Obstetrical and gynecological diseases: menstrual abnormalities, premenstrual tension, menstrual difficulties, menopausal syndrome, post-hysterectomy phytonadic disorder, female infertility. 12, urological disorders: neurogenic frequency, nocturia, urinary incontinence, pyelonephritis, IgA nephropathy, wandering kidney, prostatitis, male infertility. 13.Lumbar and lower limb disorders: lumbar pain, knee pain, tinea pedis, extremity red pain, corns, frostbite and frostbite.