A comparison of superficial versus combined (superficial and deep) cervical plexus block for carotid endarterectomy: a prospective, randomized study

The Superficial Cervical Plexus Block for Postoperative Pain Therapy in Carotid Artery Surgery. A Prospective Randomised Controlled Trial

OBJECTIVES

Rapid and reliable neurological evaluation soon after carotid artery surgery is feasible with modern methods of general anesthesia, but postoperative pain therapy remains a challenge. Use of opioids can mask neurological deficits. We investigated whether superficial cervical plexus block reduced postoperative opioid consumption after carotid endarterectomy.

DESIGN

Prospective, randomised, double-blinded, placebo controlled trial.

METHODS

46 patients undergoing unilateral carotid endarterectomy under general anesthesia were randomized to either superficial cervical block with ropivacaine (n=23) or placebo (n=23). A patient controlled analgesia device (PCA) delivering morphine was provided for all patients. Subjective pain levels (visual analog scale, VAS) were recorded. The primary outcome was total morphine consumption on discharge from the recovery room. Secondary outcomes included arterial pCO2 (as an indicator of central nervous effects of morphine) and patient satisfaction.

RESULTS

No adverse effects of the superficial cervical plexus block were reported. Four patients in the placebo group were excluded because of other drug use post-operatively. Per protocol analysis compared 23 patients in ropivacaine group and 19 patients in the placebo group. The ropivacaine group had a significant reduction in morphine consumption (3.8+/-2.0 versus 12.9+/-4.0, p<0.001), lower maximal pain scores (2.6+/-2.0 versus 5.8+/-1.6, p<0.001), and paCO2 levels (39.0+/-2.6 versus 41.9+/-3.4, p=0.008) at discharge from the recovery room. Patient satisfaction (1=very good to 6=insufficient) was substantially higher in the ropivacaine group (1.7+/-0.7 versus 3.1+/-1.2, p<00.01).

CONCLUSION

The significant and clinically relevant lower morphine consumption and pain score, as well as the substantially higher patient satisfaction demonstrate that superficial cervical plexus block provides effective pain relief for patients undergoing carotid endarterectomy.

Does clonidine 50 μg improve cervical plexus block obtained with ropivacaine 150 mg for carotid endarterectomy? A randomized, double-blinded study

STUDY OBJECTIVE

To evaluate the effects of adding 50 microg clonidine to 150 mg ropivacaine for superficial cervical plexus block in patients undergoing elective carotid endarterectomy (TEA).

DESIGN

Randomized, double-blind study.

SETTING

Departments of Anesthesia and Vascular Surgery of a university hospital.

PATIENTS

40 ASA physical status II and III patients undergoing elective TEA during superficial cervical plexus block.

INTERVENTIONS

Superficial cervical plexus block was placed using 20 mL of 0.75% ropivacaine alone (Ropi group, n = 20) or with the addition of 50 microg clonidine (Ropi-Clonidine group, n = 20). If required, analgesic supplementation was given with local infiltration with 1% lidocaine and intravenous fentanyl (50-microg boluses). Nerve block profile, need for intraoperative analgesic supplementation, and time to first analgesic request were recorded.

MEASUREMENTS AND MAIN RESULTS

Median (range) onset time was 10 minutes (5-25 min) in the Ropi group and 5 minutes (5-20 min) in the Ropi-Clonidine group (P < 0.05). Intraoperative consumption of both 1% lidocaine and fentanyl was higher in patients of the Ropi group (15 mL [0-25 mL] and 250 microg [50-300 microg]) than in patients of the Ropi-Clonidine group (8 mL [0-20 mL] and 0 microg [0-150 microg]; P < 0.05 and P < 0.05, respectively). First postoperative analgesic request occurred after 17 hours (10-24 hrs) in the Ropi group and 20 hours (10-24 hrs) in the Ropi-Clonidine group (P > 0.05).

CONCLUSIONS

Adding 50 microg clonidine to 150 mg ropivacaine for superficial cervical plexus block shortened the onset time and improved the quality of surgical anesthesia in patients undergoing elective TEA.

Adjunctive pharmacologic use in carotid endarterectomy: a review

Although carotid endarterectomy (CEA) is now widely accepted as the surgical therapy for carotid stenosis, the role of and indications and evidence for many pharmacologic agents that are used adjunctively in the perioperative setting have not been conclusively established. Aspirin (acetylsalicylic acid) is the pharmaceutical agent that has been studied most extensively in conjunction with CEA; other than aspirin and dextran, the use of many agents before, during, and after CEA has not been standardized. Prospective randomized trials are still needed to demonstrate efficacy, predict outcome, and determine the optimal use of these medications in their adjunctive use during CEA to improve patient care and obtain optimal surgical outcomes.

Acute respiratory failure after deep cervical plexus block for carotid endarterectomy as a result of bilateral recurrent laryngeal nerve paralysis

We report about a case of acute respiratory distress (73-year-old female), which occurred minutes after a deep cervical plexus block (40 ml ropivacaine 0.5%) for carotid endarterectomy (CEA) and required immediate endotracheal intubation of the patient's trachea and consecutive mechanical ventilation. Subsequently, CEA was performed under general anaesthesia (TIVA) with continuous monitoring by somatosensory-evoked potentials. After a period of 14 hours, the endotracheal tube could be removed, the patient being in fair respiratory, cardiocirculatory and neurological conditions. Retrospectively, acute respiratory distress was caused by a combination of ipsilateral plexus blockade-induced and pre-existing asymptomatic contralateral recurrent laryngeal nerve (RLN) paralysis confirmed by a postoperative ENT-check and related to previous thyroid surgery more than 50 years ago. RLN paralysis, often being asymptomatic, represents a typical complication of thyroid and other neck surgery with reported incidences of 0.5-3%. Therefore, a thorough preoperative airway check is advisable in all patients scheduled for a cervical plexus block. Particularly in cases with a history of respiratory disorders or previous neck surgery a vocal cord examination is recommended, and the use of a superficial cervical plexus block may lower the risk of respiratory complications. This may prevent a possibly life-threatening coincidence of ipsilateral plexus blockade-induced and pre-existing asymptomatic contralateral RLN paralysis.

Superficial vs combined cervical plexus block for carotid endarterectomy: a prospective, randomized study

BACKGROUND

The present study compares combined and superficial cervical plexus block in patients submitted to carotid endarterectomy (CEA) in terms of anesthetic efficacy, satisfaction of the patient and surgeon, complications resulting from the type of anesthesia, and final outcome.

METHODS

A total of 125 patients submitted to elective CEA were randomized into 2 groups: the first group was submitted to superficial cervical block and the second group to combined (superficial plus deep) cervical block.

RESULTS

No significant difference in anesthetic quality was observed between the 2 types of blocks. Complications related to the anesthetic method were observed in only 1 (1.6%) patient of the superficial block group and in 5 (7.4%) patients of the combined block group (P > .05). Anesthetic supplementation by the surgeon was necessary in 50 (81.96%) patients, with no significant difference between the 2 groups. The surgical conditions were closely similar in the 2 groups, showing no significant difference. The final morbidity and mortality in the present series was 1.6%.

CONCLUSIONS

Superficial cervical anesthetic block shows the same efficacy as combined block, with the surgical conditions being closely similar. The incidence of complications related to the anesthetic technique is higher for combined block. The type of block does not influence the final outcome of the patients.

Intraoperative management: carotid endarterectomies

The management of anesthesia for patients undergoing carotid endarterectomy is challenging and dynamic. Effective management and good outcome requires the anesthesiologist's understanding of cerebral physiology, knowledge of neck anatomy, and understanding of the rapid pathophysiologic changes that occur during carotid artery manipulations. The anesthesiologist must be flexible in the management of patients, who frequently have underlying multiorgan pathology and cardiovascular compromise. Good communication between the anesthetic and surgical teams is needed to avoid irreversible debilitating consequences for the patient.

Superficial Cervical Plexus Block for Vocal Cord Surgery in an Awake Pediatric Patient

Medialization thyroplasty is a surgical procedure that decreases the incidence of dysphonia and dysphagia in patients who have vocal cord paralysis. We report a case of a pediatric patient who underwent this procedure with minimal sedation and bilateral superficial cervical plexus blockade. The use of a regional technique provided analgesia while allowing the patient to phonate at the request of the surgeon.

IMPLICATIONS

Medialization thyroplasty is a surgical procedure that decreases the incidence of dysphagia and dysphonia in patients with vocal cord paralysis. This procedure is best performed in a patient who maintains the ability to phonate. We report a case of medialization thyroplasty in a pediatric patient after bilateral superficial cervical plexus blocks with minimal sedation.

Spread of injectate with superficial cervical plexus block in humans: an anatomical study

BACKGROUND

This study was undertaken to investigate why the superficial cervical plexus block for carotid endarterectomy is so effective. Initial consideration would suggest that a superficial injection would be unlikely to block all terminal fibres of relevant nerves. One possibility is that the local anaesthetic crosses the deep cervical fascia and blocks the cervical nerves at their roots.

METHODS

Superficial cervical plexus blocks (injections just below the investing fascia) were performed using methylene blue (30 ml) in four cadavers. In one additional control cadaver, a deep cervical plexus injection was performed. In a second control cadaver, a subcutaneous injection (superficial to investing fascia) was performed at the posterior border of the sternomastoid muscle.

RESULTS

Anatomical dissection showed that with superficial block there was spread of the dye to structures beneath the deep cervical fascia. In the first control, dye remained in the deep cervical space. In the second control, dye remained subcutaneous.

CONCLUSIONS

The superficial cervical space communicates with the deep cervical space and this may explain the efficacy of the superficial block. The method of communication remains unknown. Our findings also indicate that the suitable site of injection for the superficial cervical plexus block is below the investing fascia of the neck, and not just subcutaneous.