Stellate ganglion block

The stellate ganglion block describes blockade of the cervicothoracic sympathetic chain which provides post-ganglionic sympathetic efferents to the head, neck and upper extremities. Neural blockade is typically achieved by deposition of local anesthetic between the prevertebral fascia and longus colli muscle.

Terminology

Clusters of nerve cell bodies within the cervical sympathetic chain can be anatomically subdivided into the superior, middle, intermediate and inferior cervical ganglia. The stellate ganglion refers to a fused inferior cervical and first thoracic ganglion, present in 80% of people. While anatomically inexact, it is common practice to refer to blockade of the cervical sympathetic trunk as a stellate ganglion block.

Indications

Indications for stellate ganglion blocks include:

• sympathetically mediated pain from the head, neck and upper extremities

  • reflex sympathetic dystrophy

  • herpes zoster

• vasospasm

  • Raynaud disease

  • temporal arteritis

  • Buerger disease

• hyperhidrosis

• electrical storm ⁷

  • three or more ventricular arrhythmias within 24 hours requiring defibrillation or overdrive pacing

  • a left-sided (or bilateral) stellate ganglion block is preferred in this context ⁸

Contraindications

Contraindications are current coagulopathy, recent myocardial infarction, pathologic bradycardia, and glaucoma.

Procedure

The procedure can be done by either palpating anatomical landmarks (done mainly by pain therapists) or under fluoroscopic, ultrasound or CT guidance. Using CT guidance the stellate ganglion; which comprises of lower cervical and T1 sympathetic ganglia overlying the C7 and T1 transverse process can be accurately targeted and hence a lower volume of drug needs to be delivered. Complications rates are also low as the ganglion is accurately targeted.

The choice of local anesthetic used during the procedure varies based on indication and patient factors; overall bupivacaine (0.25% or 0.5%) is the most common agent. Absolute alcohol is injected to induce permanent neurolysis. Radiofrequency ablation can also used to cause permanent neurolysis of stellate ganglion.

Ultrasound

The patient may be positioned supine or in a lateral decubitus position. Sequential palpation of the laryngeal prominence, cricothyroid membrane, and cricoid cartilage are commonly identified external landmarks. The cricoid cartilage demarcates the level of C6, which has a prominent anterior tubercle on its transverse process, also known as the Chassaignac tubercle, forming a conspicuous sonographic landmark. Performing the procedure at this level is crucial to ensure the vertebral artery will be protected in the foramen transversarium; puncture below this level risks violation of this structure ⁸.

The ultrasound transducer is then placed slightly lateral to midline in a transverse orientation attempting to visualize the anterior tubercle of C6. The esophagus and regional vasculature should be identified to plan needle trajectory; color flow Doppler is useful for the latter. The needle should be inserted in a lateral to medial orientation, directed toward the Chassaignac tubercle. Slight redirection is then necessary to traverse the prevertebral fascia, targeting the potential space it forms with its apposition to the fascia overlying the longus colli muscle, which invests the anterior aspect of the transverse process of C6. Care should be taken to ensure injectate spreads anterior to, and circumfrentially around, the longus colli, dissecting the deep cervical fascia and carotid sheath anteriorly ¹⁰.

Complications

Complications include:

• pneumothorax

• bleeding

• infection

• allergic reaction

• intravascular injection and its consequences

• phrenic nerve or recurrent laryngeal nerve palsy

• hypotension

• injury to adjacent vascular structures (particularly the vertebral artery)

• bradycardia