Analgesic efficacy of ultrasound guided versus landmark-based bilateral superficial cervical plexus block for thyroid surgery

Background
The use of bilateral superficial cervical plexus block (BSCPB) to provide analgesia for thyroid operations remains debatable. This study was done to assess the analgesic efficacy and safety of ultrasound (US) guided or landmark-based BSCPB, performed under general anesthesia, compared to systemic narcotics in thyroid surgery.
Patients and methods
A total of 69 patients ASA I and II scheduled for thyroid surgery were randomly assigned into three groups (23 patients each): Group (US) received US guided BSCPB. Group (LM) received landmark-based BSCPB. In both groups, the block was performed under general anesthesia and before surgery using 0.5% bupivacaine 12 ml on each side. Group (C) who didn’t receive any block. We measured intra-operative hemodynamics and fentanyl requirements. We also measured postoperative analgesia within 24 h of surgery as regard: pethidine consumption, visual analogue scale (VAS) pain scores and time to first rescue analgesic demand. Postoperative nausea and vomiting (PONV) and other adverse events were noted as well.
Results
There was a significant reduction in systolic blood pressure (SBP) and heart rate (HR) in groups US and LM compared with group C. Intra-operative fentanyl requirements were significantly increased in group C compared to groups US and LM. Time to first analgesic request was significantly longer in groups US and LM than in group C. Postoperative pethidine consumption and VAS scores, measured during the first postoperative day, were significantly higher in group C than groups US and LM. No significant difference was noted between the three groups regarding PONV. No other adverse events were recorded. No significant differences were noted between groups US and LM.
Conclusion
BSCPB (US guided or landmark-based), performed under general anesthesia, effectively decreased peri-operative analgesic requirements in thyroid operations. However, there was no significant difference in analgesic efficacy or safety between US guided and landmark based BSCPB.