Depth of cervical plexus block and phrenic nerve blockade: a randomized trial

Abstract

Background and objectivesCervical plexus blocks are commonly used to facilitate carotid endarterectomy (CEA) in the awake patient. These blocks can be divided into superficial, intermediate, and deep blocks by their relation to the fasciae of the neck. We hypothesized that the depth of block would have a significant impact on phrenic nerve blockade and consequently hemi-diaphragmatic motion.MethodsWe enrolled 45 patients in an observer blinded randomized controlled trial, scheduled for elective, awake CEA. Patients received either deep, intermediate, or superficial cervical plexus blocks, using 20 mL of 0.5% ropivacaine mixed with an MRI contrast agent. Before and after placement of the block, transabdominal ultrasound measurements of diaphragmatic movement were performed. Patients underwent MRI of the neck to evaluate spread of the injectate, as well as lung function measurements. The primary outcome was ipsilateral difference of hemi-diaphragmatic motion during forced inspiration between study groups.ResultsPostoperatively, forced inspiration movement of the ipsilateral diaphragm (4.34±1.06, 3.86±1.24, 2.04±1.20 (mean in cm±SD for superficial, intermediate and deep, respectively)) was statistically different between block groups (p<0.001). Differences were also seen during normal inspiration. Lung function, oxygen saturation, complication rates, and patient satisfaction did not differ. MRI studies indicated pronounced permeation across the superficial fascia, but nevertheless easily distinguishable spread of injectate within the targeted compartments.ConclusionsWe studied the characteristics and side effects of cervical plexus blocks by depth of injection. Diaphragmatic dysfunction was most pronounced in the deep cervical plexus block group.Trial registration numberEudraCT 2017-001300-30.

Intermediate Cervical Plexus Block for Refractory Bilateral Facial Pain From a Whiplash Injury in 3 Patients: A Case Report

“…13 In our experience, we have not had reports of dyspnea suggesting diaphragmatic palsy after bilateral blocks in concordance with recent evidence. 13,15…”

“…12,13 There is evidence that local anesthetic deposited in the posterior cervical space diffuses through the porous prevertebral fascia, thereby targeting the deep cervical plexus. 13,14 Thus, a single ultrasound-guided injection can target multiple nerves that innervate the muscles and joints of the neck, which may be responsible for the variety of symptoms following whiplash. It is possible that the drugs may also target the cervical sympathetic chain that may account for some of the benefits.…”

“…6 It has an improved safety profile when compared to deep cervical plexus block. 12,13 There is evidence that local anesthetic deposited in the posterior cervical space diffuses through the porous prevertebral fascia, thereby targeting the deep cervical plexus. 13,14 Thus, a single ultrasound-guided injection can target multiple nerves that innervate the muscles and joints of the neck, which may be responsible for the variety of symptoms following whiplash.…”

Effects of Unilateral Intermediate Cervical Plexus Block on the Diaphragmatic Function in Patients Undergoing Unilateral Thyroidectomy: A Randomized Controlled Study

“… 14 However, Kim et al and Opperer et al argued that ICPB did not lead to diaphragmatic dysfunction in their studies. 10 , 11 The contradictory results between these studies may be caused by the different diagnostic criteria of diaphragmatic dysfunction. Both Kim HY and Opperer M defined diaphragmatic dysfunction depending on the difference of diaphragm movement compared with baseline level.…”

Depth of cervical plexus block and diaphragmatic dysfunction

“…We read with intense interest the recently published article by Opperer et al 1 on the comparison of the superficial, intermediate and deep cervical plexus blocks (CPB) in the provision of the hemidiaphragmatic motion and phrenic nerve blockade. We highly appreciate the efforts of the authors in conducting this outstanding study.…”