Efficacy of Adding Dexmedetomidine in Ultrasound-guided Intermediate Cervical Plexus Block for Thyroidectomy Surgery

The cervical plexus block (CPB) is one such block used to provide effective anesthesia and analgesia for surgery in the head and neck region. The cervical fascia was first described as a very strong and resisting structure, consisting of two layers, superficial and deep. But more recently classified the cervical fascia as superficial/subcutaneous and deep. The deep cervical fascia is further divided into three layers: (a) the superficial layer, which was also called the investing fascia but is now referred to as the masticator fascia, submandibular fascia or sternocleidomastoid (SCM)-trapezius fascia, (b) the middle layer, which is suggested as to be named as strap muscle fascia or visceral fascia; and (c) the deep layer or the 'prevertebral fascia'. Intermediate cervical plexus block (CPB) has been found to be very effective in procedures of neck such as thyroid surgeries and carotid endarterectomy. The duration of analgesia following the nerve blocks is a matter of concern as most of the blocks last for only a few hours. Interestingly, resurgence of the use of α2-agonists in combination with local anesthetics has dramatically improved the duration of action of these blocks. Dexmedetomidine is a potent α2 agonist and is now emerging as an adjuvant to regional anesthesia and analgesia. Little evidence is available supporting the usefulness of dexmedetomidine in bilateral intermediate CPB. Therefore, the current study will be conducted to compare the duration and effectiveness of post-thyroidectomy analgesia of bilateral intermediate CPB using 20 ml bupivacaine 0.25% (Group A) or 20 ml of bupivacaine 0.25% with 1 μg/kg dexmedetomidine (Group B).