61 Stellate Ganglion Block (Cervicothoracic Sympathetic Ganglion Block)
Stellate ganglion blocks can be performed to treat sympathetically maintained pain (reflex sympathetic dystrophy, causalgia, complex regional pain syndrome type I). The stellate ganglion is the fusion of the inferior cervical and first thoracic sympathetic ganglia. Almost all of the sympathetic innervation of the head, neck, and upper extremity travels via pathways through the stellate ganglion. The stellate ganglion is approximately 0.5 to 2.5 cm in size.1 Despite its name, the stellate ganglion is fusiform, triangular, or globular in shape on magnetic resonance scans.2 Stellate ganglion block is used to diagnose and treat chronic pain syndromes of the upper extremity and head and neck.
At the level of the first thoracic vertebral level, the stellate ganglion lies lateral and posterior to the lateral edge of the longus colli muscle. As the cervical sympathetic chain travels cephalad, it comes to lie anterior to the longus colli muscle.3,4 This muscle lies over the anterior surface of the cervical transverse processes.
Anatomic Structures to Be Identified for Stellate Ganglion Block
Inferior Thyroid Artery
The inferior thyroid artery has a tortuous course (hence its alternate name, the “serpentine” artery).5 This artery travels over the surface of the longus colli muscle from lateral to medial.
Phrenic Nerve
The phrenic nerve crosses over the anterior surface of the anterior scalene muscle from lateral to medial. On ultrasound scans the phrenic nerve appears as a small (<1 mm in diameter) monofascicular structure.6 The phrenic nerve lies adjacent to the C5 ventral ramus at the level of the cricoid cartilage (C6). Performing stellate block caudal to this level helps avoid the phrenic nerve within the lateral to medial needle path. Similarly, the superficial cervical artery (transverse cervical artery) that also lies over the anterior scalene muscle can be avoided in this fashion.
