The SAPB was performed in the operative room (OR) after anesthesia induction using the same ultrasound machine (SonoSite) and linear ultrasound transducer 8- 12 Hz. The patient was positioned in a lateral position with the operative side up and arm flexed forward; then, a linear ultrasound transducer was placed in a sagittal plane over the mid-clavicular line of the thoracic cage. Then, moving inferior-lateral direction till the fifth rib was identified in the mid-axillary line. The following structures were recognized: the rib, pleura, teres major muscle (superior), latissimus dorsi muscle (superficial and posterior), and serratus muscles muscle (deep and inferior). Under complete sterile conditions, a 22-gauge echogenic needle was introduced in-plane with respect to the ultrasound probe targeting the plane deep to the serratus anterior muscle. Then, 0.4 ml/kg of 0.25% bupivacaine was injected with continuous ultrasound guidance.

Patients in Group ESPB receive US erector spinae plane block by injecting 0.4ml/kg (bupivacaine 0.25%). Under strict aseptic precautions, The T3 spinous process is located by palpating and counting down from the C7 spinous process. A high-frequency 12 MHz linear ultrasound transducer is placed in a longitudinal orientation 3 cm lateral to the T3 spinous process corresponding to the T2 transverse process. Three muscles; trapezius (uppermost), rhomboids major (middle), and erector spinae (lowermost) will be identified superior to the hyperechoic transverse process.Using an in-plane approach a 22 G needle is inserted in caudal-cephalad direction until the tip is deep to erector spinae muscle. Correct needle tip location is confirmed by injecting 3 mL of normal saline and visualizing the linear LA spread (i.e., hydrodissection) in the fascial plane between the erector spinae muscle and the transverse process. Then, bupivacaine is injected, and visualizing the fascial plane.

Serratus anterior plane block

amount of fentanyl in mic consumed in the 24 hours postoperatively

total dose of fentanyl given during the surgical procedure

FLACC score ( Face Leg Activity Cry Consolability ) it is pediatric observational 10-point scale "Face, Leg, Activity, Cry, Consolability (FLACC) pain score.

each point is given score between 0 and 2. the maximum score is 10 the lowest is 0