patients will undergo a thoracoscopic surgery under general anesthesia with double-lumen bronchial intubation without any special treatment.

patients will receive US-guided iSLN block bilaterally with 2 ml of ( 0.5 ml of 2%lidocaine and 1,5 ml of 0.5% bupivacaine) on either side immediate after the operation concomitant with GA in order to undergo thoracoscopic surgery

A linear 4- to 12-MHz ultrasound probe will be placed in the oblique parasagittal plane to obtain an image of the hyoid bone and the thyroid cartilage. The probe will be kept parasagitally, and the following structures will be identified anteriorly to posteriorly: omohyoid muscle, sternohyoid muscle, thyrohyoid muscle, thyrohyoid membrane, superior laryngeal artery, and pre-epiglottis space.

After identifying the local anatomic structure, a needle will be inserted out-plane from anterior to posterior. The muscles above the thyrohyoid membrane will be penetrated and hydrodissected; local anesthetic will be injected into the superior laryngeal nerve space. The superior laryngeal nerve space will be located between the hyoid bone (cephalad) and the thyroid cartilage (caudal) and delimited between the thyrohyoid muscle, anteriorly, and the thyrohyoid membrane and the pre-epiglottis space, posteriorly

an established scoring system feom 0 to 4