Comparing Postoperative Analgesic Techniques for Umbilical Hernia Repair: A Randomized Trial of Ultrasound Guided Caudal, Erector Spinae, and External Oblique Interfascial Plane Blocks

The correct location of the needle tip in the fascial plane deep to the erector spinae muscle will be confirmed by injecting 0.5-1 ml of saline and observing the fluid lifting the erector spinae muscle off the transverse process while avoiding muscle distension (hydro dissection)

"The needle will be advanced at a 20-degree angle with needle tip and length visualization. A pop can be appreciated as the needle passes through the sacrococcygeal ligament.~Once the needle will be confirmed to be in the caudal space on the screen, carefully aspirate to confirm absence of CSF or blood."

the needle will be advanced until the tip lay in the plane between the external oblique muscle and intercostal muscles between the sixth and seventh ribs