Regional anaesthesia for carotid endarterectomy
2014; Elsevier BV; Volume: 114; Issue: 3 Linguagem: Inglês
10.1093/bja/aeu304
ISSN1471-6771
AutoresMark D. Stoneham, D. Stamou, Justin Mason,
Tópico(s)Intracranial Aneurysms: Treatment and Complications
ResumoSummaryRegional anaesthesia is a popular choice for patients undergoing carotid endarterectomy (CEA). Neurological function is easily assessed during carotid cross-clamping; haemodynamic control is predictable; and hospital stay is consistently shorter compared with general anaesthesia (GA). Despite these purported benefits, mortality and stroke rates associated with CEA remain around 5% for both regional anaesthesia and GA. Regional anaesthetic techniques for CEA have improved with improved methods of location of peripheral nerves including nerve stimulators and ultrasound together with a modification in the classification of cervical plexus blocks. There have also been improvements in local anaesthetic, sedative, and arterial pressure-controlling drugs in patients undergoing CEA, together with advances in the management of patients who develop neurological deficit after carotid cross-clamping. In the UK, published national guidelines now require the time between the patient's presenting neurological event and definitive treatment to 1 week or less. This has implications for the ability of vascular centres to provide specialized vascular anaesthetists familiar with regional anaesthetic techniques for CEA. Providing effective regional anaesthesia for CEA is an important component in the armamentarium of techniques for the vascular anaesthetist in 2014. Regional anaesthesia is a popular choice for patients undergoing carotid endarterectomy (CEA). Neurological function is easily assessed during carotid cross-clamping; haemodynamic control is predictable; and hospital stay is consistently shorter compared with general anaesthesia (GA). Despite these purported benefits, mortality and stroke rates associated with CEA remain around 5% for both regional anaesthesia and GA. Regional anaesthetic techniques for CEA have improved with improved methods of location of peripheral nerves including nerve stimulators and ultrasound together with a modification in the classification of cervical plexus blocks. There have also been improvements in local anaesthetic, sedative, and arterial pressure-controlling drugs in patients undergoing CEA, together with advances in the management of patients who develop neurological deficit after carotid cross-clamping. In the UK, published national guidelines now require the time between the patient's presenting neurological event and definitive treatment to 1 week or less. This has implications for the ability of vascular centres to provide specialized vascular anaesthetists familiar with regional anaesthetic techniques for CEA. Providing effective regional anaesthesia for CEA is an important component in the armamentarium of techniques for the vascular anaesthetist in 2014. Editor's key points•The authors review the use of regional anaesthesia in carotid endarterectomy.•They note the reduced hospital stay, but the similar rate of stroke, compared with general anaesthesia.•Methods of achieving regional anaesthesia are detailed, and the authors note the improvements in the equipment available. •The authors review the use of regional anaesthesia in carotid endarterectomy.•They note the reduced hospital stay, but the similar rate of stroke, compared with general anaesthesia.•Methods of achieving regional anaesthesia are detailed, and the authors note the improvements in the equipment available. Regional anaesthesia for carotid endarterectomy (CEA) became commonplace in the UK in the 1990s, but significant changes in anaesthetic techniques have taken place since the last major review was published.1Stoneham MD Knighton JD Regional anaesthesia for carotid endarterectomy.Br J Anaesth. 1999; 82: 910-919Abstract Full Text PDF PubMed Scopus (83) Google Scholar Regional anaesthetic techniques have evolved—in particular, the use of nerve stimulators and ultrasound to detect peripheral nerves. This review will focus on the whole process of regional anaesthesia for CEA, including: preoperative assessment and preparation, regional anaesthetic techniques, the choice of sedative and local anaesthetic (LA) drugs, the available evidence comparing regional and general anaesthetic (GA) techniques, perioperative arterial pressure management, and the treatment options for patients developing neurological deficits after carotid cross-clamping. We searched the electronic databases; PubMed and National Library of Medicine from 1999 to 2013 using the phrases 'carotid endarterectomy', together with: 'epidemiology', 'pathophysiology', 'superficial cervical plexus block', 'deep cervical plexus block', 'intermediate cervical plexus block', 'single injection', 'multiple injection', 'monitoring', 'sedation', 'propofol', 'remifentanil', 'clonidine', 'dexmedetomidine', 'analgesia', 'cross-clamping', 'blood pressure management', 'complications', 'hyperperfusion syndrome', 'cranial nerve injuries', 'stroke', 'shunting', and 'ultrasound guided regional anaesthesia'. We looked for articles, reviews, and case reports that described new techniques or developments in regional anaesthesia. We also searched the reference list of relevant articles for further references. For this article, we did not consider animal studies. Preoperative hypertension is a risk factor for postoperative stroke and death,2Bond R Narayan SK Rothwell PM Warlow CP Group ECSTC Clinical and radiographic risk factors for operative stroke and death in the European carotid surgery trial.Eur J Vasc Endovasc Surg. 2002; 23: 108-116Abstract Full Text PDF PubMed Scopus (93) Google Scholar so patients with uncontrolled hypertension require close attention to perioperative arterial pressure control. Specific figures for preoperative arterial pressure targets have not been defined from controlled trials, but a sensible target is that systolic and diastolic arterial pressures are ≤180 and ≤100 mm Hg, respectively.3Stoneham MD Thompson JP Arterial pressure management and carotid endarterectomy.Br J Anaesth. 2009; 102: 442-452Abstract Full Text Full Text PDF PubMed Scopus (89) Google Scholar The 2012 National Guidelines for Stroke recommend that carotid intervention for recently symptomatic severe carotid stenosis should be regarded as an emergency procedure in patients who are neurologically stable, and should ideally be performed within 48 h of a transient ischaemic attack or minor stroke and definitely within 1 week,4Intercollegiate Stroke Working Party National Clinical Guidelines for Stroke. London.Available from https://www.rcplondon.ac.uk/resources/stroke-guidelinesDate: 2012Google Scholar as the benefits of carotid surgery decrease rapidly after this. Implementation of these recommendations means that there is less time for preoperative patient preparation, including arterial pressure control, which could predispose to arterial pressure lability. An estimation of the patient's 'normal' arterial pressure should be obtained from several sources including the clinic visit, the preoperative assessment clinic, and the anaesthetic room—this is the minimum arterial pressure accepted during the period of carotid cross-clamping.3Stoneham MD Thompson JP Arterial pressure management and carotid endarterectomy.Br J Anaesth. 2009; 102: 442-452Abstract Full Text Full Text PDF PubMed Scopus (89) Google Scholar Arterial pressure should be measured in both arms using the correct techniques described by the British Hypertension Society.5British Hypertension Society Hypertension: clinical management of primary hypertension in adults.Available from http://www.bhsoc.org/latest-guidelines/sub-page-11/Date: 2011Google Scholar The patient's neurological status should be assessed before operation, and neurological deficit(s) documented, as differences detected in the postoperative period potentially require surgical re-exploration.6Hans SS Results of carotid re-exploration for post-carotid endarterectomy thrombosis.J Cardiovasc Surg (Torino). 2007; 48: 587-591PubMed Google Scholar It is worthwhile noting the patient's presenting neurological complaint, for example, amaurosis fugax, dysphasia, etc. If the patient develops a neurological deficit when the carotid cross-clamp is applied, they commonly present with the same symptoms that they first presented with (M.D.S., unpublished observations). Anti-hypertensive medications should usually be continued except for angiotensin-converting enzyme inhibitors and angiotensin II receptor antagonists,7Comfere T Sprung J Kumar MM et al.Angiotensin system inhibitors in a general surgical population.Anesth Analg. 2005; 100: 636-644Crossref PubMed Scopus (183) Google Scholar but reductions in arterial pressure should be avoided in patients with neurological symptoms.3Stoneham MD Thompson JP Arterial pressure management and carotid endarterectomy.Br J Anaesth. 2009; 102: 442-452Abstract Full Text Full Text PDF PubMed Scopus (89) Google Scholar β-Blockers protect against perioperative cardiac complications in patients with a history of myocardial ischaemia,8Flynn BC Vernick WJ Ellis JE β-Blockade in the perioperative management of the patient with cardiac disease undergoing non-cardiac surgery.Br J Anaesth. 2011; 107: i3-15Abstract Full Text Full Text PDF PubMed Scopus (24) Google Scholar but this is offset by an increased risk of stroke in higher dose regimes9Devereaux PJ Yang H Yusuf S et al.Effects of extended-release metoprolol succinate in patients undergoing non-cardiac surgery (POISE trial): a randomised controlled trial.Lancet. 2008; 371: 1839-1847Abstract Full Text Full Text PDF PubMed Scopus (1713) Google Scholar and in patients who become acutely anaemic (although acute anaemia is rare in patients undergoing CEA).10Beattie WS Wijeysundera DN Karkouti K et al.Acute surgical anemia influences the cardioprotective effects of beta-blockade: a single-center, propensity-matched cohort study.Anesthesiology. 2010; 112: 25-33Crossref PubMed Scopus (93) Google Scholar The American College of Cardiology recommendations for perioperative β-block include continuation if already taking but not to start unless specifically indicated.11Fleischmann KE Beckman JA Buller CE et al.2009 ACCF/AHA focused update on perioperative beta blockade.J Am Coll Cardiol. 2009; 54: 2102-2128Crossref PubMed Scopus (109) Google Scholar Metoprolol is associated with increased risk of stroke in patients undergoing non-cardiac surgery compared with other selective drugs such as atenolol or esmolol and should probably be avoided.12Mashour GA Sharifpour M Freundlich RE et al.Perioperative metoprolol and risk of stroke after noncardiac surgery.Anesthesiology. 2013; 119: 1340-1346Crossref PubMed Scopus (55) Google Scholar Statins should be continued as there is evidence of up to a 3% reduction in the incidence of stroke after CEA.13Durham CA Ehlert BA Agle SC et al.Role of statin therapy and angiotensin blockade in patients with asymptomatic moderate carotid artery stenosis.Ann Vasc Surg. 2012; 26: 344-352Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar Antiplatelet therapy has a theoretical, therapeutic benefit both at the thrombogenic endarterectomy site and in the coronary circulation in high-risk vascular patients. Aspirin is recommended for all vascular patients in the perioperative period,13Durham CA Ehlert BA Agle SC et al.Role of statin therapy and angiotensin blockade in patients with asymptomatic moderate carotid artery stenosis.Ann Vasc Surg. 2012; 26: 344-352Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar but the situation regarding clopidogrel is less clear. There is certainly evidence in patients undergoing CEA of the benefits of dual antiplatelet therapy (aspirin combined with low-dose clopidogrel) to reduce the rate of micro-embolization after operation,14Payne DA Twigg MW Hayes PD Naylor AR Antiplatelet agents and risk factors for bleeding postcarotid endarterectomy.Ann Vasc Surg. 2010; 24: 900-907Abstract Full Text Full Text PDF PubMed Scopus (25) Google Scholar and a Cochrane review of randomized trials found significant protection against stroke in patients receiving clopidogrel.15Engelter S Lyrer P Antiplatelet therapy for preventing stroke and other vascular events after carotid endarterectomy.Stroke. 2004; 35: 1227-1228Crossref PubMed Scopus (18) Google Scholar Neither the incidence of clinically important neck haematoma14Payne DA Twigg MW Hayes PD Naylor AR Antiplatelet agents and risk factors for bleeding postcarotid endarterectomy.Ann Vasc Surg. 2010; 24: 900-907Abstract Full Text Full Text PDF PubMed Scopus (25) Google Scholar, 16Stoner MC Defreitas DJ Process of care for carotid endarterectomy: perioperative medical management.J Vasc Surg. 2010; 52: 223-231Abstract Full Text Full Text PDF PubMed Scopus (25) Google Scholar nor the morbidity rate from haemorrhagic complications increases in patients undergoing CEA taking clopidogrel with or without aspirin.17Wait SD Abla AA Killory BD Starke RM Spetzler RF Nakaji P Safety of carotid endarterectomy while on clopidogrel (Plavix). Clinical article.J Neurosurg. 2010; 113: 908-912Crossref PubMed Scopus (16) Google Scholar Surgery may take longer;18Chechik O Goldstein Y Behrbalk E Kaufman E Rabinovich Y Blood loss and complications following carotid endarterectomy in patients treated with clopidogrel.Vascular. 2012; 20: 193-197Crossref PubMed Scopus (20) Google Scholar however, careful consideration should be given to the risks and benefits of performing regional anaesthesia in these patients.19Hall R Mazer CD Antiplatelet drugs: a review of their pharmacology and management in the perioperative period.Anesth Analg. 2011; 112: 292-318Crossref PubMed Scopus (160) Google Scholar There is no evidence available in the literature on the safety of performing CEA under GA or regional anaesthesia techniques in patients receiving newer, faster onset and offset antiplatelet drugs such as ticagrelor or prasugrel or any other of the newer oral anticoagulants.20Benzon HT Avram MJ Green D Bonow RO New oral anticoagulants and regional anaesthesia.Br J Anaesth. 2013; 111: i96-113Abstract Full Text Full Text PDF PubMed Scopus (67) Google Scholar The cervical plexus is formed by the ventral rami of the first four cervical nerves (C1–4). The nerves pass laterally along the corresponding transverse process immediately posterior to the vertebral artery and vein. The deep branches are entirely motor and supply the neck muscles. The superficial branches are sensory and supply the skin and subcutaneous tissues of the neck and posterior aspect of the head. It is possible for the anaesthetist or the surgeon to anaesthetize the tissues layer by layer using large volumes of dilute LA along the line of incision, and thereafter at each dissection plane and finally into the carotid sheath. This represents the simplest and, by default, rescue technique for a less than adequate block or when procedures are to be done by anaesthetists less familiar with nerve blocks. However, most clinicians choose to utilize a formal regional anaesthetic technique. Cervical epidural anaesthesia can provide suitable conditions for carotid surgery.21Michalek P David I Adamec M Janousek L Cervical epidural anesthesia for combined neck and upper extremity procedure: a pilot study.Anesth Analg. 2004; 99: 1833-1836Crossref PubMed Scopus (26) Google Scholar An epidural catheter is sited at C6–7 and a dilute anaesthetic solution such as bupivacaine 0.25% injected. However, bilateral cervical and upper thoracic nerve roots are affected resulting in significant side-effects, including hypotension, bradycardia, and respiratory impairment. Other complications include conversion to GA, dural tap, epidural haematoma, and direct spinal cord damage. Although epidural anaesthesia is used infrequently in the UK, it may be useful for more extensive procedures, for example, carotid cross-overs and combined carotid–subclavian reconstructions.21Michalek P David I Adamec M Janousek L Cervical epidural anesthesia for combined neck and upper extremity procedure: a pilot study.Anesth Analg. 2004; 99: 1833-1836Crossref PubMed Scopus (26) Google Scholar An epidural catheter may be 'topped up' for prolonged procedures, although this has also been described with deep cervical block.22Jones HG Stoneham MD Continuous cervical plexus block for carotid body tumour excision in a patient with Eisenmenger's syndrome.Anaesthesia. 2006; 61: 1214-1218Crossref PubMed Scopus (11) Google Scholar Single injection posterior cervical paravertebral block at the C4 level using a nerve stimulator is another technique of blocking C2–4 dermatomes, which may reduce the risk of accidental vascular injury or injection.23Boezaart AP Nosovitch MA Carotid endarterectomy using single injection posterior cervical paravertebral block.Anesth Analg. 2005; 101: 1885-1886Crossref PubMed Google Scholar The technique for this block has been described previously.1Stoneham MD Knighton JD Regional anaesthesia for carotid endarterectomy.Br J Anaesth. 1999; 82: 910-919Abstract Full Text PDF PubMed Scopus (83) Google Scholar, 24de Sousa AA Filho MA Faglione W Carvalho GT Superficial vs combined cervical plexus block for carotid endarterectomy: a prospective, randomized study.Surg Neurol. 2005; 63: S22-S25Abstract Full Text Full Text PDF PubMed Scopus (41) Google Scholar Superficial block is performed superficial to the investing layer of deep cervical fascia.25Telford RJ Stoneham MD Correct nomenclature of superficial cervical plexus blocks.Br J Anaesth. 2004; 92 (author reply 775–6): 775Abstract Full Text Full Text PDF PubMed Scopus (29) Google Scholar Large volumes, for example, 20–30 ml of LA agents, are typically used. An oft-cited disadvantage of superficial compared with deep block is said to be that it does not provide neck muscle relaxation,26Masters RD Castresana EJ Castresana MR Superficial and deep cervical plexus block: technical considerations.AANA J. 1995; 63: 235-243PubMed Google Scholar although this has not been shown to be important clinically. This block is performed as a single (C3 or C4–5)27Merle JC Mazoit JX Desgranges P et al.A comparison of two techniques for cervical plexus blockade: evaluation of efficacy and systemic toxicity.Anesth Analg. 1999; 89: 1366-1370PubMed Google Scholar or multiple injection technique (C2, C3, C4).28Gratz I Deal E Larijani GE Domsky R Goldberg ME The number of injections does not influence absorption of bupivacaine after cervical plexus block for carotid endarterectomy.J Clin Anesth. 2005; 17: 263-266Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar With the patient supine and the head turned towards the opposite side and slightly up, the cervical transverse processes are palpated behind sternocleidomastoid. After skin disinfection and intradermal infiltration with lidocaine, a 50 mm, 25 G block needle is introduced aiming slightly caudally and posteriorly until the cervical transverse process is encountered, usually 1–2 cm under the skin. Single-injection blocks cause less pain during the block,27Merle JC Mazoit JX Desgranges P et al.A comparison of two techniques for cervical plexus blockade: evaluation of efficacy and systemic toxicity.Anesth Analg. 1999; 89: 1366-1370PubMed Google Scholar although the number of injections does not appear to affect overall block efficacy. Single injections may be associated with less systemic absorption of LA.27Merle JC Mazoit JX Desgranges P et al.A comparison of two techniques for cervical plexus blockade: evaluation of efficacy and systemic toxicity.Anesth Analg. 1999; 89: 1366-1370PubMed Google Scholar The deep block has been implicated with a higher risk of accidental involvement of deep structures, such as the carotid and vertebral arteries, the phrenic nerve, dura mater, and the sympathetic trunk.24de Sousa AA Filho MA Faglione W Carvalho GT Superficial vs combined cervical plexus block for carotid endarterectomy: a prospective, randomized study.Surg Neurol. 2005; 63: S22-S25Abstract Full Text Full Text PDF PubMed Scopus (41) Google Scholar Continuous deep block has been described and may be considered in high-risk cases in which the procedure may be prolonged. An 18 G Tuohy needle is directed towards the C3 transverse cervical process using 1 mA current. Once paraesthesia is encountered in the anterior region of the neck, a 20 G catheter is inserted and secured at 4 cm depth (catheter tip to skin distance).22Jones HG Stoneham MD Continuous cervical plexus block for carotid body tumour excision in a patient with Eisenmenger's syndrome.Anaesthesia. 2006; 61: 1214-1218Crossref PubMed Scopus (11) Google Scholar Intermediate cervical plexus block refers to an injection of LA in the space between the superficial and deep cervical fascia25Telford RJ Stoneham MD Correct nomenclature of superficial cervical plexus blocks.Br J Anaesth. 2004; 92 (author reply 775–6): 775Abstract Full Text Full Text PDF PubMed Scopus (29) Google Scholar (although the existence of the deep fascia has been disputed).29Pandit JJ Dorje P Satya-Krishna R Investing layer of the cervical fascia of the neck may not exist.Anesthesiology. 2006; 104: 1344Crossref PubMed Scopus (9) Google Scholar Intermediate block should theoretically reduce complications of deep block such as intrathecal or intra-arterial injection, although there is no evidence supporting this. The technique is straightforward. A needle is inserted perpendicularly to the skin midpoint and posteriorly to the sternocleidomastoid to a depth of 15 mm, just below the superficial cervical fascia. This depth guide may not be valid in obese patients.30Barone M Diemunsch P Baldassarre E et al.Carotid endarterectomy with intermediate cervical plexus block.Tex Heart Inst J. 2010; 37: 297-300PubMed Google Scholar There may be a perception of 'loss of resistance'. The efficacy of superficial (subcutaneous) and intermediate cervical blocks appears similar.31Ramachandran SK Picton P Shanks A Dorje P Pandit JJ Comparison of intermediate vs subcutaneous cervical plexus block for carotid endarterectomy.Br J Anaesth. 2011; 107: 157-163Abstract Full Text Full Text PDF PubMed Scopus (39) Google Scholar Combined superficial and deep cervical plexus block is commonly practiced and consists of a deep injection plus superficial or intermediate block.32Pandit JJ Bree S Dillon P Elcock D McLaren ID Crider B A comparison of superficial versus combined (superficial and deep) cervical plexus block for carotid endarterectomy: a prospective, randomized study.Anesth Analg. 2000; 91: 781-786Crossref PubMed Scopus (89) Google Scholar Superficial and combined blocks appear to be equally efficacious.24de Sousa AA Filho MA Faglione W Carvalho GT Superficial vs combined cervical plexus block for carotid endarterectomy: a prospective, randomized study.Surg Neurol. 2005; 63: S22-S25Abstract Full Text Full Text PDF PubMed Scopus (41) Google Scholar, 32Pandit JJ Bree S Dillon P Elcock D McLaren ID Crider B A comparison of superficial versus combined (superficial and deep) cervical plexus block for carotid endarterectomy: a prospective, randomized study.Anesth Analg. 2000; 91: 781-786Crossref PubMed Scopus (89) Google Scholar Nerve stimulators may be used to identify the deep cervical plexus. A short-bevelled, 50 mm block needle connected to a nerve stimulator is inserted perpendicular to the skin consecutively at C2, C3, and C4. A current of 0.5 mA may elicit neck muscle contractions; ipsilateral head twitch;28Gratz I Deal E Larijani GE Domsky R Goldberg ME The number of injections does not influence absorption of bupivacaine after cervical plexus block for carotid endarterectomy.J Clin Anesth. 2005; 17: 263-266Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar elevation and internal rotation of the scapula;27Merle JC Mazoit JX Desgranges P et al.A comparison of two techniques for cervical plexus blockade: evaluation of efficacy and systemic toxicity.Anesth Analg. 1999; 89: 1366-1370PubMed Google Scholar paraesthesia over the upper arm, shoulder,33Mehta Y Juneja R Regional analgesia for carotid artery endarterectomy by Winnie's single-injection technique using a nerve detector.J Cardiothorac Vasc Anesth. 1992; 6: 772-773Abstract Full Text PDF PubMed Scopus (19) Google Scholar neck; or paraesthesia radiating up to the ear. By identifying diaphragmatic muscle response, a nerve stimulator may avoid administration of the LA directly onto the phrenic nerve, thereby avoiding phrenic nerve palsy.34Zeiden A Hayek F Nerve stimulator-guided cervical plexus block for carotid endarterectomy.Anaesthesia. 2007; 62: 299-300Crossref Scopus (4) Google Scholar Additional nerve blocks have also been described to supplement cervical plexus block. Submandibular and referred dental pain commonly occur, which may not respond to administration of supplemental LA.35Madi-Jebara S Yazigi A Haddad F Hayek G Severe dental pain during carotid endarterectomy under cervical plexus block.J Cardiothorac Vasc Anesth. 2001; 15: 356-357Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar This pain may be ameliorated by anaesthetizing the mandibular division of the trigeminal nerve via the intraoral approach.36Bourke DL Thomas P Mandibular nerve block in addition to cervical plexus block for carotid endarterectomy.Anesth Analg. 1998; 87: 1034-1036PubMed Google Scholar This may be useful in patients with short necks, where there is a high carotid bifurcation or where the atheromatous plaque extends cranially in the internal carotid artery.37Krovvidi H Thomas W Danks J Supplementary intraoral inferior alveolar block improves the quality of regional anesthesia during carotid endarterectomy: experience with 100 cases.J Clin Anesth. 2008; 20: 406Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar Ultrasound can demonstrate the cutaneous branches of the superficial cervical plexus and their relation to the surrounding anatomy. The advantages over the landmark technique are the ability to visualize the spread of LA in the correct plane and to avoid inadvertent damage to, or accidental puncture of, neighbouring structures. However, ultrasound guidance has not been shown to improve the success of superficial cervical plexus blocks.38Tran dQ Dugani S Finlayson RJ A randomized comparison between ultrasound-guided and landmark-based superficial cervical plexus block.Reg Anesth Pain Med. 2010; 35: 539-543Crossref PubMed Scopus (43) Google Scholar The superficial cervical plexus lies laterally to the posterior border of the sternocleidomastoid muscle. It can be visualized as a linear streak of hypoechoic nodules, which have a honeycomb appearance, below the prevertebral fascia and immediately above the interscalene groove (Fig. 1). Using aseptic technique, a high-resolution linear transducer is placed transversely over the midpoint of the sternocleidomastoid muscle (usually at the level of the cricoid cartilage, where the external jugular vein crosses sternocleidomastoid). With an in-plane or out-of-plane technique, a 50 mm nerve block needle is advanced adjacent to the superficial cervical plexus in the plane deep to sternocleidomastoid, underneath the prevertebral fascia and immediately above the interscalene groove (Fig. 2). After negative aspiration, 10–15 ml of LA is placed in this fascial plane while visualizing the spread of the LA with ultrasound. High concentrations of LA agent are not required since the superficial cervical plexus comprises purely sensory nerves.39Narouze S Sonoanatomy of the cervical spinal nerve roots: implications for brachial plexus block.Reg Anesth Pain Med. 2009; 34: 616Crossref PubMed Scopus (9) Google Scholar The transverse processes are easily visualized subcutaneously with ultrasound. The vertebral artery makes a prominent loop between C1 and C2, which may be visualized and is an accurate landmark for the transverse process of C2. The C2 spinal nerve lies inferior and posteriorly to the vertebral artery at this level. The vertebral artery is most susceptible to inadvertent puncture at this point but avoided by visualization with ultrasound. The C3 and C4 spinal nerves exit in the gutters of the transverse processes and posterior to the vertebral artery. Vertebral artery injection with the needle positioned over the C3 and C4 transverse processes is virtually impossible. The neck is scanned from the mastoid process to Chassaignac's tubercle allowing identification of the relevant anatomy. The transverse processes appear as a hyperechoic formation with posterior acoustic dropout on ultrasound, which is lost when the probe is moved further caudally. With strict asepsis under ultrasound guidance, a 50 mm nerve block needle is advanced until contact is made with the transverse process (Fig. 3). After negative aspiration, 5 ml of LA is injected, which may be repeated at each level.40Sandeman DJ Griffiths MJ Lennox AF Ultrasound guided deep cervical plexus block.Anaesth Intensive Care. 2006; 34: 240-244Crossref PubMed Google Scholar Fifteen to 20 ml of ropivacaine is deposited, with ultrasound guidance, in the fascial band between the sternocleidomastoid and levator scapulae muscle.41Perisanidis C Saranteas T Kostopanagiotou G Ultrasound-guided combined intermediate and deep cervical plexus nerve block for regional anaesthesia in oral and maxillofacial surgery.Dentomaxillofac Radiol. 2013; 42: 29945724Crossref PubMed Scopus (13) Google Scholar This is effective when combined with a perivascular carotid sheath block using 3–5 ml 0.5% ropivacaine and requires little LA supplementation during carotid surgery.42Rössel T Kersting S Heller AR Koch T Combination of high-resolution ultrasound-guided perivascular regional anesthesia of the internal carotid artery and intermediate cervical plexus block for carotid surgery.Ultrasound Med Biol. 2013; 39: 981-986Abstract Full Text Full Text PDF PubMed Scopus (29) Google Scholar Most LA agents have been used for cervical plexus block. Ropivacaine and
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