Local Distribution of a Low Dose of Anesthetic for Cervical Plexus Block in Carotid Endarterectomy

Abstract

Cervical plexus block (CPB) for carotid endarterectomy is typically performed with a large amount of anesthetic solution (20–40 ml). Our aim was to demonstrate the local distribution of a low dose of anesthetic solution for CPB. Ten patients (aged 66–79 years) underwent CPB with a single injection technique using 8 ml of ropivacaine 0.75% mixed with 1 ml of iodinated non-ionic contrast agent. Digital fluoroscopy and computed tomography (CT) were performed to define the anesthetic distribution before carotid endarterectomy. Effectiveness of the block was evaluated during and after surgery. The cranial-caudal extent of the anesthetic solution in the paravertebral space was demonstrated by both digital fluoroscopy and CT: C2–C4 (n=1), C2–C5 (n=1), C2–C6 (n=1), C2–C7 (n=5), and C3–C7 (n=2). In addition, CT showed an anterior-posterior spreading of 2–3 cm in diameter in five patients and of more than 3 cm in five patients. All patients had a sufficient deep and superficial CPB; superior cervical ganglion block was obtained in three patients, with a prevalent anterior spreading of the anesthetic in two of them. Out of the seven patients without superior cervical ganglion block, none had a prevalent anterior spreading and two had mild pain during artery dissection. We observed phrenic nerve block in ten, brachial plexus block in eight, and laryngeal block in one patient, other side effects in none. Digital fluoroscopy and CT demonstrate the anesthetic distribution in neck spaces. A dose of anesthetic low as 8 ml of ropivacaine 0.75%, seems to be sufficient to obtain CPB for carotid endarterectomy.