Erector Spinae Plane Block vs Quadro-Iliac Plane Block After Lumbar Instrumentation Surgery

An ultrasound-guided Erector Spinae Plane Block will be performed at the end of surgery, before extubation, with the patient in the prone position under standard sterilization conditions. The ultrasound probe will be placed in the parasagittal plane at the level corresponding to the surgical site to visualize the transverse process and erector spinae muscle. Following confirmation of correct needle placement with 2 mL of normal saline, 20 mL of 0.25% bupivacaine will be injected into the fascial plane deep to the erector spinae muscle. The block will be performed bilaterally, with a total volume of 40 mL, as part of a standardized multimodal postoperative analgesia protocol.

An ultrasound-guided Quadro-Iliac Plane Block will be performed at the end of surgery, before extubation, with the patient in the prone position under standard sterilization conditions. A convex ultrasound probe will be placed at the level where the quadratus lumborum muscle attaches to the iliac crest to visualize the erector spinae muscle and the underlying quadratus lumborum muscle. The block location will be confirmed with the injection of 2 mL of isotonic solution, followed by the injection of 20 mL of 0.25% bupivacaine. The spread of the local anesthetic between the erector spinae muscle and quadratus lumborum muscle will be observed under ultrasound guidance. The block will be performed bilaterally, with a total volume of 40 mL, as part of a standardized multimodal postoperative analgesia protocol.