Quadratus Lumborum Block Using Loss-of-resistance Versus Ultrasound-guided Technique

ِA blunted 22-G, 11 mm, short-bevel facet needle will be introduced in the paravertebral line at the level of L3 or L4, in 30-45 degree to the skin directing it laterally. Once the skin barrier is breached, the needle will be withdrawn back so that the tip lies just under the skin. The needle will be advanced through the posterior thoracolumbar fascia and a first fast "pop" sensation will be felt when the needle pierced it. With further advancement of the needle, a second deep pop will be felt after it pierces the middle thoracolumbar fascia. At this point, the needle will be in the plane of the quadratus lumborum block type II. After careful aspiration, the 30 mLs of local anaesthetic will be injected. The needle will be visualized by the ultrasound by another physician to ensure safety.

A broadband (5-8 MHz) convex transducer will be placed transversely in the abdominal flank above the iliac crest to identify the external oblique, internal oblique, transversus abdominis muscles and aponeurosis. Then the external oblique muscle will be followed posteriorly until its posterior border is visualized (hook sign), and the posterior aspect of the Quadratus lumborum muscle is confirmed. A 22-G, 11-mm, short-bevel facet needle will be advanced under direct ultrasound visualization in-plane from anterolateral to postero-medial. Then the 30 ml of local anesthetic (bupivacaine 0.25 %) will be injected into the lumbar inter-facial triangle (LIFT) behind the quadratus lumborum muscle using hydro-dissection.