Anatomy of cervical sympathetic chain. (Reprint with permission from Philip Peng Educational Series)
Painful medication conditions:
Sympathetically mediated pain of the upper extremity, head, or neck
Acute herpes zoster or postherpetic neuralgia of the head, neck, or upper thorax
Phantom limb pain
Cluster headache or atypical vascular headache
Intractable angina pectoris
Non-painful medication conditions:
Obliterative vascular disease
Refractory ventricular arrhythmia
Post-traumatic stress disorders
Anticoagulated patient or coagulopathy
Preexisting contralateral phrenic nerve palsy
Recent myocardial infarction
Cardiac conduction block
Only unilateral blocks should be performed to avoid bilateral recurrent laryngeal nerve block and resulting stridor.
Position: Semi-lateral decubitus position, with the neck turned contralateral
Probe: Linear 6–13 MHz
Scan 1: Place the probe at the C6 level (Figs. 3.3 and 3.4). Identify the key landmarks, including the longus colli muscle (LC), longus capitis muscle (LCa), prevertebral fascia (arrows), cervical nerve root (N), carotid artery (C), and internal jugular vein (∗∗). At this level, the transverse process has a prominent anterior tubercle (AT).
Scan 2: To confirm the level, scan the probe caudally to the C7 level. The transverse process is the key landmark to identify at this level (Fig. 3.5). At this level, the transverse process has a prominent posterior tubercle and vestigial anterior tubercle. Use color Doppler to identify the vertebral artery.
Note that at the C6 level, the vertebral artery most commonly enters the foramen transversarium. In up to 10% of patients, the vertebral artery travels outside the foramen transversarium at the C6 or even C5 level. The figure showed the presence of vertebral artery anterior to the anterior tubercle at C5 level (Fig. 3.6).
Scan 3: At the C6 level, perform a pre-scan with and without color Doppler (Fig. 3.7). Identifying aberrant vessels and structures such as the esophagus will help plan for the safest approach, which may change in location on swallowing (Fig. 3.7). The location of the esophagus and the vessel may discourage a practitioner from performing a medial or lateral approach (see procedure below).