Cervical Sympathetic Chain and Superior Cervical Ganglion Block

Tumber, Paul; Jankovic, Danilo

doi:10.1007/978-3-030-88727-8_12

Paul Tumber³ &
Danilo Jankovic⁴

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1 Citations

Abstract

A range of indications and case reports highlight the potential benefits of a stellate ganglion block (SGB), although the effects may only be short-lived and may require repeat injections. Concurrent with the advent of ultrasound guidance technology, the SGB has become a sympatholytic procedure that can now be safely performed without the need for fluoroscopy or blind palpation techniques. In addition to the risk of potential complications with traditional approaches for SGB, precision in the deposition of the injectate and adequacy of its spread to the first and second thoracic vertebral levels are key considerations for ensuring efficacy.

The SCG is the largest of the three cervical sympathetic ganglia. The SCG block indications are mostly identical to those for the stellate ganglion block. However, due to its marked cerebro-facial effects, the superior cervical ganglion block (SCGB) is particularly suitable in situations where pain or dysfunction involves the head and face, and it may be an option in depressive conditions. The description of how to block the SCG using ultrasonography was first reported in 2013, utilizing a cadaveric model to confirm the approach’s accuracy.

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Ultrasound-Guided Cervical Sympathetic Block

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General Considerations: Stellate Ganglion Block

Concurrent with the advent of ultrasound guidance technology, the stellate ganglion block (SGB) has become a sympatholytic procedure that can now be safely performed without the need for fluoroscopy or blind palpation techniques. The initial description of using ultrasound to directly visualize the spread of local anesthesia in the neck for an SGB was by Kapral and colleagues in 1995, and this was refined and validated by Gofeld and colleagues in 2009. The volume required to perform an SGB has been reduced from 10–15 cc to 4–5 cc, and with the refinement offered by a proper ultrasound technique, there has been an associated reduction in undesirable complications such as life-threatening hematoma.

Indications

The cervical sympathetic nervous system is involved with a myriad of structures, including viscera, sweat glands, and blood vessels, and the innervation extends to the eyes, face, brain, head and neck, heart, and upper extremity (Fig.12.1). Therefore, there is a corresponding range of indications and case reports highlighting the potential benefits of a SGB, although the effects may only be short-lived and may require repeat injections.

Painful medical conditions involving the head, neck, or upper extremity

Sympathetically mediated pain/complex regional pain syndromes.
Acute herpes zoster or post-herpetic neuralgia.
Phantom limb pain.
Headache (e.g., cluster, migraine, atypical facial pain).
Intractable angina pectoris.
Joint stiffness.
Post-stroke pain (contralateral block).

Non-painful medical conditions

Raynaud’s.
Hyperhidrosis.
Lymphedema after breast amputation.
Traumatic cerebral edema.
Post-traumatic stress disorder.
Vascular conditions (obliterative vascular disease, cerebral vasospasm).
Cardiac conditions (refractory ventricular arrhythmias).
Postmenopausal flushing.
Ménierè’s disease, sudden sensorineural hearing loss, and tinnitus.
Positive effect on the immune system.

Contraindications

Anticoagulation treatment, contralateral paresis of the phrenic nerve or recurrent laryngeal nerve, glaucoma, severe emphysema, and simultaneous bilateral block.

Functional Anatomy

Sympathetic nerve cell bodies exist in the first few thoracic segments and send preganglionic sympathetic nerve fibers that ascend through the paravertebral cervical sympathetic chain. These nerve fibers synapse in the superior, middle, and inferior cervical ganglions. In approximately 80% of the population, there is a fusion of the inferior cervical ganglion with the first thoracic ganglion, and this structure is termed the cervicothoracic ganglion but is more commonly known as the stellate ganglion. The size and development of the STG are subject to considerable variation. Average sizes of between 25 mm (15–50 mm) × 3–10 mm × 5 mm have been reported. This average corresponds to the superior cervical ganglion size and is much more voluminous than the middle cervical ganglion. Some authors have only been able to identify it in 38% of individuals studied (Fig. 12.2). The stellate ganglion is situated in the region of the lower part of C7 extending to the T1 transverse process. The STG is deep to the prevertebral fascia, is often just anterior or superior to the neck of the first rib, and is closely located medial or posterior to the vertebral artery in proximity to the dome of the pleura (Fig. 12.3). Some practitioners attempted to block the STG at the C7-T1 region, but several serious complications are possible at this level, and thus it has considered safer to block the cervical sympathetic ganglia and chain at the C6 level instead. The middle cervical ganglion is variable in location and size, although it is the smallest of the three cervical sympathetic ganglia and is likely blocked at the C6 level although this has not been rigorously studied. Performance of a STB at the C6 level relies on a planar spread of the local anesthesia between the prevertebral fascia layer and the surface of the longus colli muscle in order to block the stellate ganglion (Figs. 12.4, 12.5, and 12.6). It is also judicious to choose C6 as the level for the injection as the vertebral artery becomes protected from potential needle injury as it dives into the bony foramen transversarium in at least 90% of subjects (Fig. 12.7).

Effects of the Block: Characteristic Unilateral Symptoms

Block of the STG can denervate sympathetic supply to the head, neck, and upper extremity. A successful block is demonstrated most commonly by an ipsilateral Horner’s syndrome (Fig. 12.8) and an increased skin temperature of at least 1° Celsius. Other techniques to confirm a successful block include the observation of an abolished skin resistance response and increased skin blood flow. It is possible to completely block the STG in some individuals, but there may still be sympathetic innervation maintained to the upper extremity. Such a situation may occur if there is anomalous sympathetic innervation via gray rami communicantes from the second thoracic sympathetic ganglia that pass directly to the upper limb via a second thoracic nerve that joins the first thoracic spinal nerve and ultimately onto the brachial plexus. These anomalous pathways are known as the Kuntz nerves and maybe a reason for a partial or failed effect of an STGB on the upper extremity.

Procedure for Ultrasound-Guided Stellate Ganglion Block

Preparation and Patient Positioning

The patient should be fasted as per standard anesthesia guidelines and have standard monitors applied, including an automated blood pressure cuff, electrocardiogram, and continuous pulse oximeter. Intravenous access should be established in order to treat any potential complication. Light sedation may be necessary to help the patient relax their neck muscles and shoulder, and a slight head up or reverse Trendelenburg position may help to reduce venous congestion and reduce the size of the internal jugular vein. The patient can be placed supine or turned slightly away from the side to be blocked with a wedge. The head is turned to the opposite side to help increase the distance from the carotid artery to the C6 anterior tubercle, and this can be adjusted to find the optimal position under real-time ultrasound scanning.

Scanning Technique and Sonoanatomy

A high-frequency linear ultrasound probe of 6–13 MHz is utilized (Fig. 12.9a, b). Transverse scanning can begin just above the clavicle to identify the carotid artery initially. Then deep and lateral to this can be visualized the pulsatile vertebral artery and C7 nerve root, lateral to which is the C7 posterior tubercle. The vertebral artery can then be tracked cephalad as the transducer maintains a transverse orientation, and it will disappear as it enters the C6 transverse process in 90% of individuals, whereas in the remainder, the vertebral artery will enter the bony canal at C5. The level of C6 is confirmed by the presence of a prominent anterior tubercle and a smaller posterior one, whereas at C5 the two tubercles are similar in size. At the C6 level, the longus colli muscle can be seen deep to the carotid artery and carotid sheath (which also contains the vagus nerve and internal jugular vein). Superficial and lateral to the longus colli may be seen a smaller muscle which may be the longus capitis muscle. The needle tip’s target will be a plane deep to the prevertebral fascia between the longus capitis and longus colli muscles. The middle cervical ganglion or cervical sympathetic chain may be seen in some individuals immediately overlying the longus colli muscle.

Technique

Typically, the needle is directed from lateral to medial, and an in-plane approach is used to visualize the needle tip throughout the procedure. Once the target is identified, the probe should be adjusted such that the lateral end of the probe just overlies the US image of the anterior tubercle and not the corresponding foramen. This way, the needle has a direct and short path to the target from the probe’s lateral end and can bypass the neurovascular structures lateral to the C6 anterior tubercle. A 25-gauge, 1.5-inch needle often suffices although some individuals will need a 25G or 22G spinal needle (3.5 inch) to reach the target. Before needle placement, a color Doppler scan should rule out the presence of any arteries such as the transverse inferior thyroid or smaller ascending cervical arteries that may be in the path of the needle (Figs. 12.10 and 12.11). Occasionally, a more medial out-of-plane approach may be necessary and care should be taken to visualize the needle tip as best possible as it may traverse vessels and the thyroid gland itself. In all cases, hydrodissection with small amounts of normal saline should be employed before any local anesthesia injection. Once the needle is in position, negative aspiration is confirmed.

A test dose of 0.5 mL of the local anesthetic may then be injected to confirm proper spread and lack of any immediate adverse response. A final volume of 4–5 mL is adequate to elicit a STGB, and bupivacaine 0.25–0.5% is often used (Fig. 12.12). An ipsilateral Horner’s syndrome should develop within a few minutes, and the patient should be observed for a minimum of 30 minutes after the procedure to ensure a lack of any undesirable adverse effects such as a recurrent laryngeal nerve palsy.

Dosage

Local anesthetic (e.g., 0.2–0.375–0.5 ropivacaine, 0.25–0.5% bupivacaine (0.25–0.5% levobupivacaine), or 1% prilocaine, 1% lidocaine, 1% mepivacaine).

“Low dose” for indications in the head region (cerebro-facial effects): 2 mL (for traditional technique: 2–3 mL)
“Medium-high dose” for indications in the shoulder and arm region: 4–5 mL (for traditional blind technique: 8–10 mL)

In acute intractable pain (e.g., postzosteric neuralgia), low dose of local anesthetic could be combined with steroids, opioids, or clonidine in mixture.

Block Series

If the clinical picture being treated does not show temporary improvement after the second block, there is no point in performing series of treatments. Otherwise, for all indications mentioned, a series of six to ten blocks can be carried out typically 5–7 days apart. In difficult cases (e.g., herpes zoster ophthalmicus), further blocks can also be carried out when there is a visible trend toward improvement.

Side Effects

Partial block of the following nerves :
- Phrenic nerve (ipsilateral phrenic nerve palsy and hemidiaphragm paralysis), main symptom: dyspnea with normal auscultation findings (Fig. 12.6).
- Vagus nerve, main symptom: tachycardia and hypertension (Fig. 12.4).
- Recurrent laryngeal nerve, main symptom: foreign body sensation in the throat and hoarseness. It should be noted here that in ca. 43% of individuals, anastomoses with the cervicothoracic ganglion are found (Figs. 12.4 and 12.5).
- Brachial plexus: a partial brachial plexus block may occur if the local anesthetic spreads into the area of the roots of C6–T1 (Fig. 12.5).
Hematoma formation (may occur in the neck but is rarely dangerous when proper ultrasound techniques are employed). Carotid puncture in a patient with atherosclerosis can lead to cerebrovascular ischemia or stroke.
Persistent coughing.
Locked-in syndrome.
Bradycardia.

Complications

Intravascular Injection

Leading to seizure, coma, and cardiovascular collapse as it is recognized that even small amounts of local anesthesia injected in arteries in the neck can lead to disastrous effects (see Chap. 5, “Local Anesthetic Systemic Toxicity”). In particular, there is a risk of injection into the vertebral artery (the diameter of which is ca. 0.3 mm larger on the left side than on the right). More rarely, there is a risk of puncturing the carotid artery, the inferior thyroid artery, or the first intercostal artery (Fig. 12.7).

Epidural or Subarachnoid Injection

(See Chap. 41, Neuraxial Blocks: Spinal and Epidural Anesthesia; Complications, p.604). There is a risk of perforating the dural membrane if the needle is inserted incorrectly toward the nerve root. Cerebrospinal fluid (CSF) pressure is very low in the cervical area and it is almost impossible to aspirate CSF. High epidural anesthesia or high spinal anesthesia is extremely rare. It can lead to bradycardia, hypotension, and possibly to respiratory arrest and loss of consciousness. The first signs are heaviness in the limbs, sweating, dyspnea, apprehension, and anxiety.

Pneumothorax (Figs. 12.3 and 12.6)

The incidence of this complication is low. If it occurs at all, it usually produces a small pneumothorax that resolves spontaneously. If there is suspicion of a pneumothorax, a chest radiograph is required after 4–6 h.

Esophageal perforation or tracheal perforation (extremely rare)
Cardiac arrest

Practical Tips

Patients should be forewarned about the expected development of a Horner’s syndrome as a sign of a successful block and the expected warmth that develops in the upper extremity if it is cold beforehand. Patients should understand beforehand the challenge posed by the STGB and that it is not unusual to have some degree of hoarseness, dysphagia, and foreign body sensation for hours after the block. When performing the US-guided block, it is easy to apply enough pressure with the transducer to occlude the internal jugular vein, so the pressure should be minimal at first to help identify this structure, and then more pressure is applied as it improves visualization of the target. It may be necessary for the needle to traverse the IJ vein and this does not normally cause a problem. In some patients, it may be helpful to angle the probe with the medial end more caudad than the lateral end of the probe as this may help improve the visualization of a clear trajectory from lateral to medial and assist in avoiding the carotid artery contents. Inject only a small amount of lidocaine to anesthetize the skin before needle placement as the lidocaine may cause undesirable numbness on the side of the neck by blocking branches of the superficial cervical plexus. If the correct subfascial plane is not easy to visualize, then one can deliberately advance the needle into the longus colli muscle. Then an injection of small 0.5 mL aliquots with slow withdrawal of the needle tip will allow visualization of the change in the spread seen from the typical intramuscular injection pattern to the anticipated planar spread pattern seen just under the prevertebral fascia (the injectate should envelope the longus colli muscle in an inverted U shape).

Literature Review

There are various case reports of STGB being therapeutic for several painful and non-painful conditions involving the upper extremity, head, neck, and heart. Typically, local anesthesia is employed, but there have been reports of using pulsed radiofrequency of the stellate ganglion. There is also a report of using long-acting liposomal bupivacaine to try and prolong the benefit from a STGB as well as placing a catheter for continuous infiltration of local anesthesia. In current practice, a stellate ganglion block is commonly performed with US guidance at the C6 level, and it blocks a length of the cervical sympathetic chain from about C4 to the first thoracic vertebral level. Ultrasound has the added benefit of being a portable technique that allows one to avoid radiation exposure. The use of US guidance allows for identifying important structures relevant to the successful blockade of the cervical sympathetic chain. It is critical to maintain real-time visualization of the needle as it advances toward the target in addition to using hydrodissection with normal saline before active drug administration. There is still a need for more research to support many of the reported indications for stellate ganglion blockade.

Traditional Approach for SGB (Paratracheal Anterior Technique)

The injection can be made at the level of C6 or C7. The transverse process of the sixth cervical vertebra is easily palpated at the level of the cricoid; the distance from the pleura is greater and there is less danger of puncturing the vertebral artery. Block at the level of C7 can extend as far as T3, with a reduced dose of local anesthetic. However, the likelihood of injuring the pleura or puncturing the vertebral artery is greater here (Fig. 12.13). For palpation of the site between the larynx and the sternocleidomastoid muscle, a cushion is placed under the shoulder blades and the head is tilted back. The index and middle fingers are moved between the trachea and sternocleidomastoid muscle to locate the pulse in the common carotid artery. This is displaced laterally together with the medial margin of the sternocleidomastoid muscle. After skin infiltration, a 22-gauge, 3–5-cm needle with injection tube (depending on patient’s anatomy) is introduced vertical to the skin at this point and advanced until bone contact is made with the transverse process (2–4 cm). After bone contact, the needle is withdrawn about 1–2 mm, and with careful aspiration at various levels, an initial test dose of 0.5–1 mL of the local anesthetic is injected (Fig. 12.14). After approximately 1 min, slow injection of the remaining dose can be injected in small portions. Two effects of the block need to be distinguished: after 1–2 min, Horner’s syndrome develops due to cerebral facial spread. This can be achieved with a low dose of the local anesthetic. Complete block, including the shoulder and arm region, requires a higher dose, and the local anesthetic needs to spread as far as T4.

Practical Tips

If there is no bone contact or paresthesias in the brachial plexus are elicited, the needle must be withdrawn and corrected medially. If the transverse process is still not reached, the needle’s direction should be carefully corrected caudally or cranially. A single test dose by no means guarantees correct positioning of the needle. The remaining dose must never be injected quickly and carelessly. It must be administered slowly in small quantities (several test doses) with constant aspiration.

Disadvantages and Limitations of Non-ultrasound-Guided Approaches

Possible consequences of non-ultrasound-guided approaches are as follows:

Potential for penetration of vascular structures and intravascular injection:

Retropharyngeal and cervicomediastinal hematomas after SGB have been reported despite negative aspiration tests, causing severe airway compromise. Possibility of other arteries of risk (e.g., the ascending cervical branch of the inferior thyroid artery, transverse cervical artery) that traverse over the C6 anterior tubercle has also been mentioned. Narouze and Siegenthaler found that the vertebral or other arteries were located in the needle path for traditional approach for SGB in over 28% of subjects, while Bhatia and colleagues reported that major vessel was observed in up to 29 and 43% of patients at the C6 and C7 levels, respectively. It was also noted that the vertebral artery was outside the foramen transversarium in 7% of subjects at the C6 level.
Potential for penetration of the esophagus, pleura, lateral lobes of the thyroid gland, and cervical nerve roots:

The recent studies have indicated that the esophagus is frequently located in the needle path of SGB performed using traditional approaches. The esophagus was located along the needle path in 37–50% and 65–74% of subjects at the C6 and C7 levels, respectively, in these studies. Pneumothorax is also a potential complication with anatomic landmark- or fluoroscopy-guided techniques, primarily if a SGB is performed at the C7 level. Finally, a needle traversing through the thyroid gland can result in a hematoma, and exiting cervical nerve roots can also be traumatized during SGB.

Conclusion

In addition to the risk of potential complications with traditional approaches for SGB, precision in the deposition of the injectate and adequacy of its spread to the first and second thoracic vertebral levels are vital considerations for ensuring efficacy. The location of CST is in the loose connective tissues of the prevertebral fascia. However, traditional approaches rely on contact with bony landmarks (transverse processes of C6 or C7) followed by the needle’s withdrawal by a few millimeters and then injection. The spread of injectate seen with these approaches has been anterior to the prevertebral fascia and in most patients’ paratracheal space, without much caudal spread In contrast a subfascial injection results in a more caudal spread, a higher rate of sympathetic block of the upper limbs, and a lower incidence of blockade of the vagus or recurrent laryngeal nerve.

General Considerations: Superior Cervical Ganglion Block

The SCG is the largest of the three cervical sympathetic ganglia. Selective block of this ganglia can be therapeutic for a variety of craniofacial conditions, and the block may now be performed with ultrasonography whereas in the past a blind intraoral or fluoroscopic/CT approach was required. Most of the evidence reported about this selective block is limited to case series or retrospective analysis. More research is needed to determine the optimal technique and volume of local anesthesia to use and understand its role versus a standard cervical sympathetic ganglion block performed at the C6 level. This does not appear to be a common block, and there are no active research trials underway according to Clinical Trials.gov.

Indications

The areas of application are partly identical to those for the stellate block, but due to its marked cerebro-facial effects, the superior cervical ganglion block (SCGB) is particularly suitable in situations where there was pain or dysfunction involving the head and face, such as:

Migraine,
Cluster headache, headaches of cervical origin,
Neuropathic pain of the head/neck region,
Cerebral vasospasm and microvascular ischemia,
Central post-stroke syndrome (contralateral block!),
Peripheral facial paralysis facial pain,
Vertigo (of vertebral origin),
Tinnitus,
Trigeminal neuralgia in the 1st and 2nd branches*,
Acute herpes zoster or post-herpetic neuralgias (otic, ophthalmic)*,
Glossopharyngeal neuralgia,
Hyperhidrosis in the head region,
Asthma, allergic coryza,
Depression (S.below)

* SCGB in combination with pterygopalatine ganglion block may be useful (Coauthors clinical experience over many years) (See. Chaps. 8 and 9)

Contraindications

(See above, SGB)

Functional Anatomy (Figs. 12.15, 12.16, 12.17, and 12.18)

The SCG is usually formed by the fusion of the upper four cervical paravertebral sympathetic ganglia and contains the preganglionic sympathetic nerve fibers that synapse with postganglionic sympathetic fibers that travel widely to the head and neck. Rami communicants connect the SCG with structures such as the carotid arteries, the pharyngeal plexus of CN IX (glossopharyngeal) and CN X (vagus) (Figs. 12.15, 12.16, and 12.17) the eye, tympanic and choroid plexus, lacrimal gland, salivary glands, thyroid and pineal gland. The widest part is often noted to be at the C2-3 level, and it often assumes a vertical fusiform shape but may also appear flattened. In cadavers, it may be an average length of 26.6 mm (14–43 mm), 7.2 mm in width and 3.4 mm in depth.

In a cadaveric study of 30 subjects, the SCG was reliably located just above the carotid artery bifurcation. The SCG lies in a plication of the deep cervical fascia, separate from the sheath that encloses the carotid artery, vagus nerve and internal jugular vein. An MRI study confirms that the SCG is usually located medial to the internal carotid sheath and superficial to the longus capitis muscle at the level of C2.

Procedure for Ultrasound-Guided Superior Cervical Ganglion Block

Siegenthaler and colleagues first described how to block the SCG using ultrasonography in 2013, utilizing a cadaveric model to confirm the accuracy of the approach. Subsequently, there has been a case report using US guidance to block the SCG by pulsed RF ablation to treat refractory migraine and another case report using local anesthesia to improve recovery from abducens nerve palsy caused by microvascular ischemia.