The principal contraindication to CEA is the patient’s general medical condition. In patients with severe asymptomatic primary atherosclerotic carotid artery stenosis or recurrent carotid artery stenosis, a more prudent decision may be medical therapy alone, especially if the patient has severe comorbidities and a limited life expectancy. A relative contraindication may be previous surgery or radiation therapy to the operative field, which may increase the risk of inadvertent cranial nerve injury. Such injuries are life altering and every bit as devastating to the patient as a major stroke. Such considerations may make an endovascular approach a better option. While not a “contraindication,” proximal common carotid or innominate artery stenoses must be corrected before carotid bifurcation surgery.

For carotid procedures we usually use superficial and/or deep cervical plexus block with intravenous sedation. We reserve general anesthesia with endotracheal intubation
for patients who cannot tolerate regional block, for example, severe back pain, claustrophobia, and benign essential tremors. All patients must have adequate intravenous access, pulse oximetry, and have an arterial line inserted for blood pressure monitoring. On occasion, when it has not been possible to place a reliable arterial line, we will use a sphygmomanometer alone for arterial blood pressure monitoring.

General anesthesia is perfectly acceptable for CEA. Indeed, the one randomized control trial investigation both techniques showed them to be equally safe. Of course, general anesthesia raises the question of how best to ensure cerebral perfusion during carotid clamping. In the past, some surgeons adopted a “no-shunt” approach. While counterintuitive to most, the one contemporary review of routine shunting with a “no-shunting” approach showed no difference in stroke rates (3.4% in the no-shunt group vs. 3.7% in the shunt group; P = 0.64). Despite this, many surgeons either shunt all patients, making neurologic monitoring redundant, or selectively shunt depending on predefined monitoring criteria. Centers differ in their preferences for monitoring devices and the expertise available to them. The commonly used monitoring techniques to determine cerebral malperfusion are changes in electroencephalography (EEG) tracings, ICA stump pressure measurements (less than 25 to 75 mm Hg stump systolic blood pressure upon CCA clamping, depending on center and surgeon), somatosensory-evoked potentials (SSEPs), near-infrared spectroscopy (NIRS), or transcranial Doppler.

Position and patient comfort is especially important when procedures are performed under regional anesthesia. A restless patient will make the surgery difficult if not impossible. The patient is placed in the supine position with their head supported by a gel head ring or doughnut. The neck is extended and the head is rotated 15 to 20 degrees away from the surgeon. This moves the mandible superiorly and facilitates access to the carotid arteries. A note of caution, avoid the temptation to rotate the neck further than this as it can lead to the plane of dissection being developed too medially as the operation progresses leading to exposure of the lateral wall of the trachea.

Excessive extension will also be counterproductive. The sternocleidomastoid muscle will become taut and internal jugular vein will rotate anterior to the carotid arteries rather than remaining in a lateral position. It is also an unpleasant position for an awake patient. We support the shoulders with rolled towels and attach adhesive tape from each side of the table to the other, across the patient’s forehead to maintain head position. We also find it useful to place the patient in a 15- to 20-degree “head-up” or reversed Trendelenburg position for two reasons: patient comfort, especially when performing procedures under regional anesthesia and to decrease venous pressure and congestion and so lessen bleeding. We prepare the skin with chlorhexidine, square off the surgical site and use, and an antimicrobial adhesive drape to secure the drapes. Always allow time (at least 3 minutes) for the chlorhexidine to dry. We always ensure that the sternoclavicular joint and the ear lobe are exposed.

Exposure of the carotid artery is identical with either method of endarterectomy. Some surgeons mark the carotid bifurcation by ultrasound prior to surgery in order to minimize the incision. We softly feel the carotid bifurcation. At its maximal pulsation we make an incision 1 cm below and extend it as needed. The incision is anterior to the sternocleidomastoid and usually midway between the mastoid and the sternoclavicular joint. The platysma is divided with electrocautery and the external jugular vein is ligated and divided. The superficial cervical fascia is divided and the sternocleidomastoid muscle is retracted posteriorly. The anterior facial vein (which can be single or multiple) arises from the anterior surface of the internal jugular vein. It is ligated and divided. Often lymph nodes are encountered at this stage and they should be freed up medially and retracted laterally to facilitate exposure of the carotid arteries.

We usually dissect the CCA first. It is important to manipulate the carotid arteries as little as possible before clamping to prevent distal embolization. The vagus nerve lies directly posterior or posterolateral to the CCA and is usually readily separated from the artery. Care must be taken when applying a clamp on the CCA not to inadvertently
crush the vagus nerve, which will result in vocal cord paralysis. The superior laryngeal nerve branch off the vagus passes posterior to and just above the carotid bifurcation and may be at risk during dissection in this area. The recurrent laryngeal nerve, on the other hand, usually lies in the tracheoesophageal groove, protecting it from injury. A nonrecurrent inferior laryngeal nerve (NRILN) occurs on the left in 0.004% of patients. It occurs on the right in 0.6% of patients. Type 1 NRILNs arise directly from the vagus and run together with the vessels of the superior thyroid pedicle are therefore at risk when dissecting medially or posteriorly to the carotid bulb. Types 2A and 2B run with the inferior thyroid artery and should not be at risk during CEA.

The ICA is medial and posterior to the ECA and deep the internal jugular vein. Usually it is located by continuing CCA exposure cephalad. However, distal exposure of the ICA must allow adequate space to clamp the artery and to perform the distal reconstruction. This usually means mobilization of the hypoglossal nerve, which is tethered in place by the sternocleidomastoid branches of the occipital artery and vein. These are divided along with the descending hypoglossal branch of the ansa cervicalis to allow the nerve to be moved cephalad. We avoid placing slings on the nerve to reduce the risk of traction injury, which results in dysarthria and dysphagia.

For even more distal exposure, the posterior belly of digastric muscle will also have to be divided. In this circumstance, the glossopharyngeal nerve is at risk and care must be taken to identify and preserve it as it runs along the superior border of the digastric in close proximity and superficial to the ICA. Isolated glossopharyngeal nerve palsy results in loss of ipsilateral gag reflex, taste in the posterior one-third of the tongue, a dry mouth from decreased salivation and poor pharyngeal elevation with speaking and swallowing. However, most swallowing problems after carotid surgery are not due to damage to the glossopharyngeal nerve, which is largely a sensory nerve only supplying motor fibers to the stylopharyngeus muscle, but rather from injury to motor fibers of the vagus nerve. These lie within a thin membrane bounded inferiorly by the hypoglossal nerve and superiorly by the glossopharyngeal nerve.

We have never had to divide the ramus of the mandible or subluxate it in elective CEA. Once distal exposure is satisfactory, one must fully dissect the carotid bifurcation and clear all carotid body fibers and connective tissue from around the ICA to free it up circumferentially. This allows for rapid proximal transection and distal division of the ICA. When performing this operation under cervical block (our usual practice), the patient will often experience some discomfort when the carotid sinus tissues are divided, so we commonly supplement the block in this area with 2 to 3 mL of 1% lidocaine. The distal extent of the plaque can be gauged by a change in the external color of the ICA from which to a blue hue. The ICA may also appear softer and more compressible beyond the end of the plaque. This is important as the greatest fear for the uninitiated, especially when performing eversion CEA is being unable to “get beyond” the plaque to clamp it and so allow for good visualization of the “endpoint” following endarterectomy.