IRCT20170826035905N1 IRCT 2017-12-27 Vice Chancellorfor Research of Tehran University of Medical Sciences Control of pain after thyroidectomy Efficacy of the Sono-guided superficial cervical plexus block on post operative pain of thyroidectomy surgery: A double blind randomized study 2018-01-21 anticipated 100 Complete https://irct.ir/trial/26997 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Used, Assignment: Parallel, Purpose: Supportive, Randomization description: Randomization will be done by 4 block size, Blinding description: double blind. N/A post thyroidectomy pain. Intervention 1: Intervention group: The intervention group included an ultrasound superficial cervical plexus block based on anatomical landmark bilaterally in the posterior region of the middle part of the sternocleidomastoid muscle with ten cc of 0.2% ropivacaine plus epinephrine 1/200.000 . Intervention 2: Control group: In the control group instead of ropivacaine as the local anesthetic; 10 cc normal saline as a placebo is used to inject. No - There is not a plan to make this available Justification or reason for not sharing IPD is we will send it privately on request