Glossopharyngeal and Maxillary Nerve Blocks in Adenotonsillectomy

For the procedure, anesthesiologist will turn patient face carefully toward the clinician, and a linear ultrasound probe will be placed in the neck to check the surrounding target structures: the sternocleidomastoid muscle, the common carotid artery, and the internal jugular vein. After the sternocleidomastoid muscle has been identified, a linear ultrasound probe will be placed parallel to sternocleidomastoid muscle fiber direction just caudal to the mandibular ramus. The stylohyoid muscle is easily visualized by tiling the linear ultrasound probe toward the mandibular ramus. In this area, the stylohyoid muscle is positioned under the sternocleidomastoid muscle, and both can be observed under ultrasound guidance. A 25-gauge, 25-mm needle will be inserted deeply under the stylohyoid muscle through the sternocleidomastoid muscle via an out-of-plane approach. An ultrasound-guided nerve block will be performed with 3 mL of 0.25% bupivacaine after the absence of blood backflow is confirmed.

Curvilinear ultrasound probe will be placed in infra-zygomatic area, over maxilla, angled 45° cephalad. This probe position allows visualization of pterygopalatine fossa, limited anteriorly by maxilla and posteriorly by greater wing of sphenoid. A 22- gauge, 5-cm needle will be inserted perpendicularly to the skin following aseptic preparation of the skin at the frontozygomatic angle formed by posterior orbital rim and zygomatic. Once contact was made with the greater wing of sphenoid, needle will be redirected caudally and medially, and advances through the pterygomaxillary fissure into pterygomaxillary fossa. needle will be advanced using an out-of-plane approach, and needle tip can usually be identified during movements. Needle placement will be verified by real-time ultrasound guidance and negative aspiration before administration of 3-4 ml of 0.25 % bupivacaine. The same procedure will be then repeated on the contralateral side.

ultrasound-guided maxillary nerve (UGMN) and ultrasound-guided glossopharyngeal nerve block (UGSGNB) using normal saline as placebo effect