The Vertebral Artery is Unlikely to be the Sole Source of Vascular Complications Occurring during Stellate Ganglion Block

Introduction:  Stellate ganglion block (SGB) is commonly performed for upper extremity complex regional pain syndrome and other conditions. Known complications of stellate block include Horner's syndrome, hoarseness, hematoma formation, airway compromise, immediate seizure (presumably from vertebral artery injection), and death. A previous arterial anatomy study demonstrated other vessels, eg, the ascending and deep cervical arteries, reinforcing the blood supply of the spinal cord and brain stem. The potential role of these vessels in the pathogenesis of seizures or hematoma during SGB has not been studied. Methods:  The anatomical recording log from 10 cadaver dissections and photographic records of same were reviewed to ascertain the presence of the ascending or deep cervical arteries, or other branches emanating from the thyrocervical or costocervical trunk and their relationship to the medial anterior surface of the C6 and C7 transverse processes. Results:  In 4 cases, as determined by the dissection log, and in 6 cases, determined by photographic images, the ascending cervical artery or a branch from the thyrocervical trunk passed over the anterior aspect of the transverse processes of C6 or C7. Discussion:  Arterial vessels other than the vertebral artery that also supply the anterior spinal cord and brain stem pass directly anterior to the transverse processes at the most common sites of the SGB. It is anatomically possible, therefore, that accidental injection or induced spasm of these vessels and not the vertebral arteries is responsible for some cases of seizure, hematoma, or other vascular complications during SGB.