Caudal Block Versus Quadratus Lumborum Plane Block in Lumbar Surgery

In the prone position , linear transducer will be first positioned transversely on the middle line. The two sacral cornua appear as two hyperechoic structures ,two hyperechoic band structures are present between the two sacral cornua. The superficial is the sacrococcygeal ligament (SCL) and the deep is the dorsal surface of the sacrum. The sacral hiatus is a hypoechoic area between two band-like hyperechoic structures. In longitudinal view, the block needle will be inserted using the in plane technique .The block needle can be visualized in real time piercing the SCL entering the hiatus but cannot be visualized beyond the apex of the hiatus. It is therefore proposed to limit the extension of the needle tip beyond the tip of the sacral hiatus to 5 mm to avoid perforating the dura mater. After the needle is inserted in the caudal canal, 20 ml of 0.25% bupivacaine will be injected.

The patient is placed in the prone position , under aseptic conditions with the sterile convex probe is placed in a transverse view at the triangle of the QL muscle and the middle thoracolumbar fascia. The projected needle path is advanced in-plane until the needle tip is visualized between the middle thoracolumbar fascia and the QL muscle . After confirming the location of the needle with 2-3 ml of saline and then aspiration, 20 ml of 0.25% bupivacaine is injected in this plane with confirmation by visualizing hydro dissection . the procedure is applied to the opposite side using the same dose to achieve bilateral block.