The aim of the present study is to evaluate and compare the analgesic efficiency of the difference concentration between 0.125% and 0.25% bupivacaine provided by ultrasound guided posterior quadratus lumborum block undergoing LPEC in children

Fifty participants both male and female aged from 1 to 6 years old, AGED FROM 1 TO 6 YEARS OLD, ASA class I to II undergoing elective Laparoscopic percutaneous extraperitoneal closure for pediatric inguinal hernia and hydrocele will be randomly divided into two equal groups of twenty five by using computer generated random table.

All received premedication in the form of midazolam 0.1 mcg/kg IV. Perioperative monitoring included continuous ECG, NIBP and pulse oximetry. Baseline reading of these were recorded. General anesthesia will be inducted using thiopental 5 mg/kg then atracurium 0.5 mg/kg to facilitate endotracheal tube intubation and fentanyl 1 mcg/kg. Anesthesia will be maintained using 2% isoflurane with oxygen to air 40:60.

Posterior quadratus lumborum block (The technique which local anesthetic agent is injected at middle thoracolumbar fascia between erector spina muscle and quadratus lumborum muscle) provided by GE, LOGIQe VERSION (12L-RS, LINEAR ARRAY) ultrasound guided and using stimuplex needle 22G-2 inches on both sides under sterile technique in lateral position will be performed in all patients immediately after induction and before starting surgery. patients will be allocated randomly into two equal groups, twenty five in each as the following GROUP 1 will receive 0.25% bupivacaine 0.4 ml/kg. per each side. GROUP 2 will receive 0.125% bupivacaine 0.4 ml/kg. per each side. The patients and parents along with independent anesthesiologist and attending nurses were not aware of group allocation.

The surgical intervention was started not less than 10 minutes after block. Pneumoperitonium pressure was limited not exceed 10 mmHg. After completion of surgery, anesthesia was discontinued and muscle relaxant was reversed as usual. After extubation, the patients will be transfer to PACU.

Postoperative pain will be assessed by attending nurses, using CHEOPs SCORE. Acetaminophen 10 mg/kg. orally will be given as rescue analgesia for patient with CHEOPs SCORE more than 6. Parameters will be assessed

Intraoperative measurements:

1. Hemodynamic parameters: HR and MAP were recorded before, immediately and every 5 minutes after induction of anesthesia until the end of the operation.
2. Analgesic requirement: All through the procedure (By measure analgesic need intraoperative in the form of fentanyl 0.5 mcg/kg) In case of increase in intraoperative MAP or HR of more than 20% from baseline.
3. Incidence of complications: In the form of hypotension, hematoma, intraabdominal organ injury LAST.

Postoperative measurements:

1. Quality of analgesia: Assessed immediately postoperatively every 30 minutes in the PACU and then at 4, 8, 12 hours at ward using CHEOPs SCORE and 24 hours postoperatively using PARENT'S POSTOPERATIVE PAIN MEASUREMENT(PPPM).
2. Incidence of complications: In the form assessment of intensity of motor block by using MODIFIED BROMAGE SCORE, vomiting and hemodynamic instability.
3. Others: In the form of parent's satisfaction of analgesia and length of hospital stay.

Inclusion Criteria:

• Children scheduled for laparoscopic percutaneous extraperitoneal closure(LPEC) for pediatric inguinal hernia and hydrocele
• ASA I-II physical status patients
• Complete inform consent for intervention

Exclusion Criteria:

• Contraindication for regional anesthesia
• Sensitive to local anesthetic agent, opioid or acetaminophen
• Previous history of abdominal surgery
• History of neuromuscular disease
• G6PD deficiency