Cervical plexus block enhanced pain control for unilateral thermal ablation of thyroid nodules

Despite being minimally invasive, thermal ablation (TA) of thyroid nodules may still cause significant pain during and shortly afterwards. Conventional analgesia relies on perithyroidal local anesthesia (PLA) with or without sedation. The use of cervical plexus block (CPB) has been extensively studied in thyroidectomy, but never studied in TA of the thyroid gland. This study examined whether adding ultrasound-guided CPB to PLA and sedation could further reduce post-operative pain in unilateral TA of thyroid nodules.

Consecutive patients aged ≥18 years undergoing unilateral radiofrequency ablation (RFA) or microwave ablation (MWA) of thyroid nodules were reviewed. Group I patients did not receive CPB, and Group II patients received CPB by bupivacaine injection between the sternocleidomastoid muscle (SCM) and prevertebral fascia on the treatment side. Pain was charted immediately and 4 hours after ablation using a numeric rating scale (NRS) of 0-10. The Quality-of-Recovery-9 (QoR9) questionnaire was completed.

Over an 18-month period, 100 patients underwent unilateral thyroid ablation (Group I, n=50; Group II, n=50). Comparable baseline patient demographics, nodule characteristics, ablation parameters were noted (P>0.05). Significantly lower immediate NRS {1 [0-3] vs. 4 [1.3-6], P<0.001}, 4-hour NRS {1 [0-3] vs. 2 [0-4], P=0.04}, and more zero immediate NRS (44% vs. 14%, P=0.001) was observed in Group II. Total QoR9 scores were comparable {16 [12-17] vs. 15 [12-17], P=0.72}. No adverse events occurred. All patients were discharged within the same day.

Adding ultrasound-guided CPB further enhanced pain control following unilateral TA of thyroid nodules, without compromising quality of recovery or same-day discharge.