mTLIP vs QIPB for Postoperative Analgesia in Lumbar Microdiscectomy Surgery

This is a fascial plane block in which a local anesthetic is injected into the interfascial plane between the longissimus and iliocostalis muscles. Participants in this group will undergo bilateral modified thoracolumbar interfascial plane blocks (mTLIP) under ultrasound guidance prior to surgery. Under sterile conditions, with the patient in the prone position, the ultrasound probe will be placed in the parasagittal plane at the midpoint of the surgical incision, taking into account the lumbar levels to be operated on. The paraspinal muscles will be identified, and using an in-plane technique, the needle will be advanced into the interfascial plane between the longissimus and iliocostalis muscles. Correct needle placement will be confirmed with saline solution. A total of 40 mL of 0.25% bupivacaine and 5 µg/mL (1:200,000) adrenaline-containing local anesthetic solution (20 mL for each side) will be used for the block procedures.

This is a fascial plane block is a procedure in which local anesthetic is injected at the point where the quadratus lumborum muscle attaches to the iliac crest, allowing it to spread between the erector spinae and quadratus lumborum muscles. Participants in the QIPB Group will undergo bilateral quadrioliac plane blocks (QIPB) under ultrasound guidance prior to surgery. Under sterile conditions, with the patient in the prone position, a convex ultrasound probe will be placed at the point where the quadratus lumborum muscle attaches to the iliac crest to identify the erector spinae and quadratus lumborum muscles. After confirming the needle placement with saline, a local anesthetic solution containing 0.25% bupivacaine and 5 µg/mL (1:200,000) adrenaline will be administered, total 40 mL (20 mL for each side). The spread of the local anesthetic solution between the erector spinae and quadratus lumborum muscles will be visualized