Patient Selection

This block can be performed easily in a supine patient; thus, almost any patient is a candidate. Bilateral deep cervical plexus block should be avoided because the phrenic nerve may be partially blocked with this technique. Examples of procedures that are suitable for this technique are carotid endarterectomy, lymph node biopsy, and plastic surgical procedures.

Pharmacologic Choice

Most procedures carried out with cervical plexus block do not demand significant motor relaxation. Thus, lower concentrations of local anesthetics, such as 0.75% to 1% lidocaine or mepivacaine, 0.25% bupivacaine, or 0.2% ropivacaine, are appropriate with these techniques.

Anatomy

Cervical plexus block can be divided into superficial and deep techniques. The cutaneous innervation of the cervical nerves is schematically illustrated in Figure 25-1. The cervical nerves have both dorsal and ventral rami, and those illustrated in Figure 25-2 represent the ventral rami of C1-C4. In addition, there are both sensory and motor branches from the dorsal rami of C1-C4 that are not shown. Before regrouping to form the cervical plexus, the cervical nerves exit from the cervical vertebrae through a gutter in the transverse process in an anterocaudolateral direction, immediately posterior to the vertebral artery.

Figure 25-1. Cervical plexus: anatomy and cutaneous innervation.

Figure 25-2. Cervical plexus: functional anatomy of the ventral rami of C1-C4.

To simplify understanding the cervical plexus, it can be divided into (1) cutaneous branches of the plexus, (2) the ansa cervicalis complex, (3) the phrenic nerve, (4) contributions to the accessory nerve, and (5) direct muscular branches (see Fig. 25-2). The cutaneous branches of the plexus are the lesser occipital, greater auricular, transverse cervical, and supraclavicular nerves (see Fig. 25-1