Stellate Ganglion Block
Author: Yasuyuki Shibata M.D.
Aichi Medical University
School of Medicine
Department of Anesthesiology
The cervical sympathetic nerve trunk ascends directly as far as the base of the skull. Along its course, it forms three cervical ganglia- the superior, middle, and inferior cervical ganglia. The inferior cervical ganglion located at the C7/C8 level fuses with the 1st thoracic ganglion to form the cervicothoracic ganglion (the stellate ganglion). These cervical ganglia produce gray communicating branches to the C1-8, and T1 nerve roots. The superior cervical ganglion also communicates with the internal carotid nerve, external carotid nerve, and superior cervical cardiac nerve.
The fascias of the neck are important structures that influence the extent of local anesthetic spread and complications that may occur following stellate ganglion block (SGB). The fascias of the neck are divided into 3 groups - the superficial cervical fascia, middle cervical fascia, and deep cervical fascia (figure below).
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The deep cervical fascia envelops the muscle group that encircles the cervical spine. The deep cervical fascia is also called the prevertebral fascia because it envelops the prevertebral muscles (longus colli and longus capiti muscles) that attach to the cervical vertebral bodies and transverse processes. The prevertebral fascia is divided into 2 layers - the narrowly defined prevertebral fascia and the pterygoid fascia. The cervical sympathetic nerve trunk ascends through the prevertebral layer (figure above and below). The gray communicating branches of the cervical sympathetic nerve trunk penetrate the longus colli muscle anteriorly before they reach the cervical nerves.
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Laterally from the transverse processes of the cervical vertebrae, the brachial plexus is located between the anterior and middle scalene muscles. The trachea, esophagus, thyroid gland, and carotid sheath are located between the prevertebral fascia and the middle cervical fascia. At the C6 level, the recurrent laryngeal nerve ascends in a path surrounded by the thyroid, esophagus, and trachea.
- The patient is placed in the supine position with the neck slightly hyperextended, and the mouth opened gently. In the case of a right-handed practitioner and an SGB on the right side, the practitioner stands on the right side of the patient so as to face the patient.
- For an SGB on the left side, the practitioner is located at the top end of the patient’s head.
- After skin and transducer preparation, a 11-mm broadband tightly curved array transducer is pressed between the trachea and the common carotid artery to retract the common carotid artery laterally from the transverse process of C6 (figure below).
- Optimize machine imaging capability. Select appropriate depth of field (usually within 3 cm), focus range (usually within 2 cm) and gain.
- Obtain a transverse view of the neck at the level of C6. Identify the carotid artery (CA), the internal juggler vein, the thyroid gland (TH), the trachea, the esophagus (ES, usually visible on the left side), the longus colli muscle (LC) covered with the prevertebral fascia (PF), the root of C6, (C6) and the transverse process of C6 (TP) (figure below).
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Arrows = local anesthetic spread
CA = carotid artery
C6 = C6 nerve root
ES = esophagus
LA = local anesthetic
LC = longus colli muscle
PF = prevertebral fascia
TH = thyroid gland
TP = transverse process of C6 |
The cervical sympathetic nerve trunk is within the prevertebral fascia. However it is impossible to distinguish the sympathetic nerve trunk from the prevertebral fascia. In some patients, the middle cervical ganglion is clearly visualized within the prevertebral fascia.
In ultrasound-guided SGB, the needle is not directed toward the stellate ganglion; rather the cervical sympathetic nerve trunk and its gray communicating branches at the C6 level are blocked. The cervical sympathetic nerve trunk ascends through the prevertebral fascia and its gray communicating branches penetrate the longus colli muscle from the anterior direction and communicates with the cervical nerve roots which proceed to the neck and upper limb. For that reason, it is possible to perform an C6-SGB by penetrateing the prevertebral fascia with needle and injecting local into the compartment of the longus colli muscle.
In Plane Approach
- A 25-gauge, 1-inch long-bevel needle is used for SGB.
- A fine extension tube is connected between the needle and the syringe.
- Insert the needle between the transducer and the trachea using an in-plane approach.
- Advance the needle while avoiding the thyroid gland
- Penetrate the prevertebral fascia and stop when the tip of needle reaches the inside the longus colli muscle. There is no need for the tip of needle to contact the transverse process of C6.
- Confirm negative aspiration for blood.
- Inject 0.5 mL of local anesthetic and check if the injectate has reached the longus colli muscle deep to the prevertebral fascia.
- If the spread is above the prevertebral fascia, advance the needle further.
- Once inside the longus colli muscle, inject a total of 5-8 mL of local anesthetic.
Caution
- Pay particular attention to the location of the vertebral artery and the supeior and inferior thyroid arteries. Use Color Doppler to visualize these vascular structures.
- The vertebral artery doesn’t always enter the C6 transverse foramen. It may bypass the C6 transverse foramen and enter the neural foramen at a higher cervical level.
- The superior thyroid artery is usually visualized on the lateral edge of the thyroid gland at the C6 level.
- The inferior thyroid artery ascends directly upwards and cuts across the anterior surface of the longus colli muscle.
- These arteries are located in the path of the needle in some patients.
Observe the extent of local anesthetic spread inside the longus colli muscle and bulging of the prevertebral fascia (figure below). Also scan cephalad and caudad to assess local anesthetic spread in the sagittal plane.
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Arrows = local anesthetic spread
CA = carotid artery
C6 = C6 nerve root
ES = esophagus
LA = local anesthetic
LC = longus colli muscle
PF = prevertebral fascia
TH = thyroid gland
TP = transverse process of C6 |