A Randomized Controlled Trial Examining the Effect of the Addition of the Mandibular Block to Cervical Plexus Block for Carotid Endarterectomy

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.

Local versus general anaesthesia for carotid endarterectomy

BACKGROUND

Carotid endarterectomy may significantly reduce the risk of stroke in people with recently symptomatic, severe carotid artery stenosis. However, there are significant perioperative risks that may be minimised by performing the operation under local rather than general anaesthetics. This is an update of a Cochrane Review first published in 1996, and previously updated in 2004, 2008, and 2013.

OBJECTIVES

To determine whether carotid endarterectomy under local anaesthetic: 1) reduces the risk of perioperative stroke and death compared with general anaesthetic; 2) reduces the complication rate (other than stroke) following carotid endarterectomy; and 3) is acceptable to individuals and surgeons.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, and two trials registers (to February 2021). We also reviewed reference lists of articles identified.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing the use of local anaesthetics to general anaesthetics for people having carotid endarterectomy were eligible.

DATA COLLECTION AND ANALYSIS

Three review authors independently extracted data, assessed risk of bias, and evaluated quality of evidence using the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) tool. We calculated a pooled Peto odds ratio (OR) and corresponding 95% confidence interval (CI) for the following outcomes that occurred within 30 days of surgery: stroke, death, ipsilateral stroke, stroke or death, myocardial infarction, local haemorrhage, and arteries shunted.

MAIN RESULTS

We included 16 RCTs involving 4839 participants, of which 3526 were obtained from the single largest trial (GALA). The main findings from our meta-analysis showed that, within 30 days of operation, neither incidence of stroke nor death were significantly different between local and general anaesthesia. Of these, the incidence of stroke in the local and general anaesthesia groups was 3.2% and 3.5%, respectively (Peto odds ratio (OR) 0.91, 95% confidence interval (CI) 0.66 to 1.26; P = 0.58; 13 studies, 4663 participants; low-quality evidence). The rate of ipsilateral stroke under both types of anaesthesia was 3.1% (Peto OR 1.03, 95% CI 0.71 to 1.48; P = 0.89; 2 studies, 3733 participants; low-quality evidence). The incidence of stroke or death in the local anaesthesia group was 3.5%, while stroke or death incidence was 4.1% in the general anaesthesia group (Peto OR 0.85, 95% CI 0.62 to 1.16; P = 0.31; 11 studies, 4391 participants; low-quality evidence). A lower rate of death was observed in the local anaesthetic group but evidence was of low quality (Peto OR 0.61, 95% CI 0.35 to 1.06; P = 0.08; 12 studies, 4421 participants).

AUTHORS' CONCLUSIONS

The incidence of stroke and death were not convincingly different between local and general anaesthesia for people undergoing carotid endarterectomy. The current evidence supports the choice of either approach. Further high-quality studies are still needed as the evidence is of limited reliability.

Outcomes of Carotid Endarterectomy according to the Anesthetic Method: General versus Regional Anesthesia

Background

The surgical strategies for carotid endarterectomy (CEA) vary in terms of the anesthesia method, neurological monitoring, shunt usage, and closure technique, and no gold-standard procedure has been established yet. We aimed to analyze the feasibility and benefits of CEA under regional anesthesia (RA) and CEA under general anesthesia (GA).

Methods

Between June 2012 and December 2017, 65 patients who had undergone CEA were enrolled, and their medical records were prospectively collected and retrospectively reviewed. A total of 35 patients underwent CEA under RA with cervical plexus block, whereas 30 patients underwent CEA under GA. In the RA group, a carotid shunt was selectively used for patients who exhibited negative results on the awake test. In contrast, such a shunt was used for all patients in the GA group.

Results

There were no cases of postoperative stroke, cardiovascular events, or mortality. Nerve injuries were noted in 4 patients (3 in the RA group and 1 in the GA group), but they fully recovered prior to discharge. Operative time and clamp time were shorter in the RA group than in the GA group (119.29±27.71 min vs. 161.43±20.79 min, p<0.001; 30.57±6.80 min vs. 51.77±13.38 min, p<0.001, respectively). The hospital stay was shorter in the RA group than in the GA group (14.6±5.05 days vs. 18.97±8.92 days, p=0.022). None of the patients experienced a stroke or restenosis during the 27.23±20.3-month follow-up period.

Conclusion

RA with a reliable awake test reduces shunt use and decreases the clamp and operative times of CEA, eventually resulting in a reduced length of hospital stay.

Cervical plexus block

Cervical plexus blocks (CPBs) have been used in various head and neck surgeries to provide adequate anesthesia and/or analgesia; however, the block is performed in a narrow space in the region of the neck that contains many sensitive structures, multiple fascial layers, and complicated innervation. Since the intermediate CPB was introduced in addition to superficial and deep CPBs in 2004, there has been some confusion regarding the nomenclature and definition of CPBs, particularly the intermediate CPB. Additionally, as the role of ultrasound in the head and neck region has expanded, CPBs can be performed more safely and accurately under ultrasound guidance. In this review, the authors will describe the methods, including ultrasound-guided techniques, and clinical applications of conventional deep and superficial CPBs; in addition, the authors will discuss the controversial issues regarding intermediate CPBs, including nomenclature and associated potential adverse effects that may often be neglected, focusing on the anatomy of the cervical fascial layers and cervical plexus. Finally, the authors will attempt to refine the classification of CPB methods based on the target compartments, which can be easily identified under ultrasound guidance, with consideration of the effects of each method of CPB.