Ultrasound-guided carotid sheath block for carotid endarterectomy: a case series of the spread of injectate

Abstract

Introduction: We aimed to show the spread of local anesthetic following an ultrasound-guided, double-injection technique of a carotid sheath block before carotid endarterectomy.

Methods: The study included 15 patients scheduled for elective carotid endarterectomy. The carotid sheath block was performed after ultrasound-guided localization of the carotid bifurcation (level C4-C6) at the posterior border of the sternocleidomastoid muscle. A mix of 7.5 mL ropivacaine 0.75%, 7.5 mL prilocaine1% and 3 mL iopromidum was injected at the base of the carotid bifurcation. An additional 15 mL of the mixture was administered subcutaneously at the surgical incision line. Thirty minutes after the block, a computed tomography scan of the head, neck region and upper thorax was performed to reconstruct a 3-D distribution of the injectate.

Results: All patients achieved C2-C4 dermatomal sensory blockade. None required conversion to general anesthesia. The injectate spread ranged from the vertebral body of C1 to the vertebral body of T3. The mean volume of distribution was 97±13 mL, the craniocaudal spread 138±19 mm, dorsoventral 57±8 mm and coronal 53±8 mm. The mean carotid artery circumference contact was 252°±77, with four patients (27%) presenting with a ring formation (360°) around the carotid artery.

Conclusions: Ultrasound-guided carotid sheath block provided an extensive spread of local anesthetic. A complete ring formation of local anesthetic around the artery does not seem necessary for a successful anesthesia. The resulting nerve blockade thus appears sufficient for surgery, with minor risks compared to blind methods.

Keywords: carotid endarterectomy; carotid sheath block; cervical plexus block; spread of local anesthetic; three-dimensional reconstruction; ultrasonic controlled.

Conflict of interest statement

Disclosures None declared.

Figures

Figure 1

Anatomical landmarks for performing ultrasound-guided carotid sheath block: the line connecting the angle of mandible, A), and the jugular notch of the manubrium sterni, B). Two subcutaneous local anesthetic skin-injections: on the level of C5/C6 at the horizontal projection of the cricoid cartilage for the subcutaneous local anesthesia wall for the surgical incision line and the drainage tube area, C), and the puncture site of the peripheral nerve block needle, D).

Figure 2

Spread of the local anesthetic (yellow lines). CA=carotid artery; d=dorsal; l=lateral; m=medial; v=ventral.

Figure 3

Axial native CT image of the right-sided contrast media/anesthetic injection at the submandibular level of the neck. No ring-like union of the contrast media around the carotid artery (red arrow) was achieved in this case. The yellow arrow shows to the skin-incisional infiltration. CT = computed tomography.

Figure 4

Three-dimensional image of the right-sided contrast media/anesthetic injection from the left oblique anterior angle. The yellow arrow indicated the contrast media distribution of the skin-incisional infiltration and the red arrow indicated the distribution of the carotid sheath block.

Table 1

Demographic and surgical data. BMI = body mass index; f = female; m = male; SD = standard deviation.

Table 2

Spread of radiological contrast agent. CVB=cervical vertebral body; TVB=thoracic vertebral body; SD= standard deviation.