The Effects of Ultrasound-guided and Anatomic landmark-based Superficial Cervical Plexus Block on Post-operative Pain Intensity in Thyroidectomy Patients: A Clinical Trial

Background and Objective: Pain is one of the most common complications after thyroidectomy. Opioid administration can overcome this complication, however, it has some side effects, including nausea and vomiting. So, the use of local anesthetic instead of opioids is a good alternative. This study was conducted to evaluate and compare the effect of ultrasound-guided superficial cervical plexus block (SCPB) versus anatomic landmark (LM)-based SCPB on post-operative severity of pain after thyroidectomy. Materials and Methods: In this clinical trial 113 patients were selected through convenience sampling method. Patients were randomly divided in to three groups: a) control, b) LM-based nerve block, and c) ultrasound-guided nerve block. Data collection was performed by demographic checklist and visual analogue scale (VAS). After general anesthesia, nerve block was performed by 15 mL of 0.25% Bupivacaine solution. Postoperative pain was measured in post anesthesia care unit (PACU) at 3, 6, 9, 12 and 24 hours. One-way analysis of variance (ANOVA), chi-square and fisher exact tests and repeated measurements were used for data analysis (SPSS V.18 software). Results: Patients of group c in comparison to other groups received lower analgesic dose during operation (p≤0.001); fewer of them needed post-operative analgesia (p≤0.001). The ultrasound-guided SCPB group had significantly lower pain severity in comparison to other groups in different time intervals (p≤0.001). Conclusion: Ultrasound-guided superficial cervical plexus block reduced the pain after thyroidectomy. However, the ultrasound-guided nerve block is a well-organized and expanding technique, but it needs more practice and training.