U/S-guided Continuous Quadratus Lumborum Block III in Percutaneous Nephrolithotomy

Continuous infusion of Bupivacaine 0.125 % at a rate of 0.1 ml/kg/hr (not exceeding 12 ml/hour), infused through a catheter inserted in the plane between quadratus lumborum \& psoas major muscles with ultrasound guidance.

Single injection of a mixture solution of 20 ml Bupivacaine 0.5% + 10 ml Lidocaine 2%, injected through a needle inserted at the posterior aspect of the quadratus lumborum muscle between it and erector spinae muscle with ultrasound guidance.

Intra-venous Morphine \[0.1 mg/kg\] as rescue analgesic shots when the Visual Analogue Score (VAS) for pain exceeds 4.