Spinal surgery in the thoracolumbar region is one of the most common surgeries for back and leg pain. In the perioperative period of spinal surgery, in the treatment of acute and chronic pain, in the scope of multimodal analgesics, regional anesthesia techniques can be used, except for systemic analgesics. The thoracolumbar interfascial plane (TLIP) block is one of these techniques.

TLIP block was first described in 2015. With ultrasound guidance a local anesthetic injection is performed into the thoracolumbar fascia between the multifidus and longissimus muscles. TLF is a generational structure consisting of several aponeurotic and fascial layers separating the paraspinal muscles from the muscles of the posterior abdominal wall. It extends between the 12^th rib and the crista iliaca. It is a complex myofascial and aponeurotic structure that surrounds the body, which allows the lumbar vertebral to stabilize on the sacrum. Each spinal nerve that emerges from the foramen intervertebral is divided into two branches, the ramus anterior and the ramus posterior. The anterior branches of the spinal nerves are the extremities, which are the anterior and outer parts of the trunk. The autochthons back muscles are innervates by posterior branches. The modification of the TLIP block with a lateral approach is also described.

Thoracolumbar interfascial plane (TLIP) block is an effective method for postoperative analgesia after lumbar spinal surgery in multimodal analgesia concept and ERAS applications. The TLP block significantly reduces postoperative opioid consumption.