Cervical plexus and greater occipital nerve blocks: controversies and technique update

Systematic Review and Meta-Analysis of Randomized Controlled Trials for Scalp Block in Craniotomy

BACKGROUND

Scalp block is regional anesthetic injection along nerves innervating the cranium. Scalp blocks for craniotomy may decrease postoperative pain and opioid consumption. Benefits may extend beyond the anesthetic period.

OBJECTIVE

To analyze evidence for scalp block on postoperative pain and opioid use.

METHODS

This systematic review and meta-analysis, Prospective Register of Systematic Reviews registration (CRD42022308048), included Ovid Medical Literature Analysis and Retrieval System Online, Embase, and Cochrane Central Register of Controlled Trials inception through February 9, 2022. Only randomized controlled trials were included. We excluded studies not reporting either main outcome. Duplicate reviewers performed study selection, risk of bias assessment, data extraction, and evidence certainty Grading of Recommendations Assessment, Development, and Evaluation appraisal. Main outcomes were postoperative pain by visual analog scale within 72 hours and opioid consumption as morphine milligram equivalent (MME) within 48 hours.

RESULTS

Screening filtered 955 studies to 23 trials containing 1532 patients. Risk of bias was overall low. Scalp block reduced postoperative pain at 2 through 72 hours, visual analog scale mean differences of 0.79 to 1.40. Opioid requirements were reduced at 24 hours by 16.52 MME and 48 hours by 15.63 MME.

CONCLUSION

Scalp block reduces postoperative pain at 2 through 48 hours and may reduce pain at 72 hours. Scalp block likely reduces opioid consumption within 24 hours and may reduce opioid consumption to 48 hours. The clinical utility of these differences should be interpreted within the context of modest absolute reductions, overall care optimization, and patient populations. This is the first level 1A evidence to evaluate scalp block efficacy in craniotomy.

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

Background and objectives

Cervical 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.

Methods

We 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.

Results

Postoperatively, 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.

Conclusions

We 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 number

EudraCT 2017-001300-30.

Anastomoses (Superficial Cervical Ansa) Between the Cervical Plexus and Peripheral Facial Nerve Branches: Implications for Regional Anesthesia in Carotid Endarterectomies - Anatomical Study

Purpose

Sensory innervation in the carotid triangle involves the cervical plexus, cranial nerves, and the sympathetic trunk. This innervation also applies to skin incision, including various anatomical structures with potentially different innervation, such as the skin (dermatomes), the platysma (myotomes), and the superficial layer of the cervical fascia (fasciotomes), as well as retromandibular retractor insertion (co-innervation: V, VII). The aim of this anatomical study was to develop an injection technique for carotid endarterectomies to additionally block anastomoses between the transverse cervical nerve (TCN), the cervical branch VII (CB VII), and the marginal mandibular branch VII (MMB VII). These anastomoses are also termed superficial cervical ansa (SCA).

Materials and Methods

Preparations (n=16) were performed on unembalmed donor cadavers (n=8). Subplatysmal injections (each using 5 mL of Alcian blue) were performed cranially within the carotid triangle between the anterior margin of the sternocleidomastoid muscle and the submandibular gland.

Results

Anastomoses between the TCN, CB VII, and MMB VII were stained in all preparations (n=16).

Conclusion

This anatomical study presents an ultrasound-guided subplatysmal SCA block to optimize, in addition to a cervical plexus block, the quality of anesthesia for carotid endarterectomies.

Reliability and Quality of YouTube Videos on Ultrasound-Guided Brachial Plexus Block: A Programmatical Review

BACKGROUND

Ultrasound-guided regional anesthesia has gained popularity over the last decade. This study aimed to assess whether YouTube videos sufficiently serve as an adjunctive tool for learning how to perform an ultrasound-guided brachial plexus block (BPB).

METHODS

All YouTube videos were classified, based on their sources, as either academic, manufacturer, educational, or individual videos. The metrics, accuracy, utility, reliability (using the Journal of American Medical Association Score benchmark criteria (JAMAS)), and educational quality (using the Global Quality Score (GQS) and Brachial Plexus Block Specific Quality Score (BSQS)) were validated.

RESULTS

Here, 175 videos were included. Academic (1.19 ± 0.62, mean ± standard deviation), manufacturer (1.17 ± 0.71), and educational videos (1.15 ± 0.76) had better JAMAS accuracy and reliability than individual videos (0.26 ± 0.67) (p < 0.001). Manufacturer (11.22 ± 1.63) and educational videos (10.33 ± 3.34) had a higher BSQS than individual videos (7.32 ± 4.20) (p < 0.001). All sources weakly addressed the equipment preparation and post-procedure questions after BSQS analysis.

CONCLUSIONS

The reliability and quality of ultrasound-guided BPB videos differ depending on their source. As YouTube is a useful educational platform for learners and teachers, global societies of regional anesthesiologists should set a standard for videos.

Reduced Pain and Opioid Use in the Early Postoperative Period in Patients Undergoing a Frontotemporal Craniotomy under Regional vs General Anesthesia

INTRODUCTION

This study compares the postsurgical course of frontotemporal craniotomies conducted "awake" under regional anesthesia (RA) versus "asleep" under general anesthesia (GA) to investigate postoperative recovery, pain, opioid use, and anesthesia-related side effects.

METHODS

We retrospectively reviewed craniotomies for supratentorial, intra-axial tumors with frontotemporal exposure. Chronic opioid use and emergent cases were excluded. Primary outcomes included pain scores on a 0-10 numerical rating scale, opioid use as oral morphine milligram equivalence, first time to opioid use, nausea, and sedation on the Richmond Agitation and Sedation Scale (RASS). Secondary outcomes included postoperative seizures, Karnofsky Performance Scale (KPS) status, and hospital length of stay (LOS).

RESULTS

A total of 91 patients met inclusion criteria: 56 underwent a craniotomy under RA versus 35 under GA. Demographics and operative characteristics were similar between cohorts. A significant reduction in both postoperative pain and opioid use was observed among RA versus GA (first postoperative pain score 2 vs. 5, P < 0.01; postoperative day [POD] 0 median pain score 2.5 vs. 4, P < 0.01; POD 0 mean opioid in mg 14.49 vs. 24.43, P < 0.01). The time until patients requested opioids for pain after surgery was prolonged for RA versus GA [mean 7.23 vs. 3.42 hours, P < 0.01). Somnolence (RASS < 0) on POD 0 was significantly reduced among RA versus GA, with 23% versus 43%. Both cohorts had equivocal postsurgical outcomes such as seizures, KPS, and hospital LOS.

CONCLUSIONS

Frontotemporal craniotomy under RA during awake craniotomies provides better pain control, a reduction in opioid use, and less somnolence in the early postoperative period.