Lumbar microdiscectomy is a commonly used surgical procedure for treating herniated discs. Effective postoperative analgesia is crucial for early mobilization and functional recovery. Uncontrolled postoperative pain can delay recovery, increase the risk of opioid dependence, and lead to respiratory complications.

Although opioid analgesics effectively reduce pain, they can cause side effects such as nausea, vomiting, respiratory depression, and dependency. Therefore, non-opioid analgesic methods are preferred for patient safety and comfort. Recently, regional anesthesia techniques such as the Thoracolumbar Interfascial Plane (TLIP) block and the Quadro Iliac Plane Block have been introduced for postoperative pain management in lumbar surgeries. However, there are not enough studies comparing the superiority of these two methods.

Study Objective: The primary aim of this study is to evaluate the effects of ultrasound-guided TLIP and Quadro Iliac Plane Blocks on postoperative opioid consumption after lumbar microsurgery. The secondary aim is to compare opioid-related side effects (such as nausea, vomiting, respiratory depression, etc.) and postoperative NRS pain scores between the groups.

Lumbar microdiscectomy is a widely performed surgical procedure for the treatment of lumbar disc herniation. Ensuring optimal analgesia during the postoperative period is crucial for promoting functional recovery and early mobilization. Inadequate control of postoperative pain may delay the healing process, increase the risk of opioid dependence, and lead to respiratory complications.

Although opioid analgesics are effective in alleviating pain during the postoperative period, they can cause adverse effects such as nausea, vomiting, respiratory depression, and an increased risk of dependence. Therefore, the implementation of non-opioid analgesic strategies is essential for maintaining patient safety and comfort. In recent years, regional anesthesia techniques, including the Thoracolumbar Interfascial Plane block and the Quadro Iliac Plane Block, have been utilized for postoperative pain management in lumbar surgeries. However, there is insufficient evidence directly comparing the effectiveness of these two methods.

Purpose of the Study: The primary objective of this study is to evaluate the impact of ultrasound-guided Thoracolumbar Interfascial Plane and Quadro Iliac Plane Blocks on postoperative opioid consumption following lumbar microsurgery. Additionally, the secondary objective is to compare the incidence of opioid-related side effects (such as nausea, vomiting, and respiratory depression) and patients' postoperative pain scores, measured using the Numeric Rating Scale, between the two groups.

Inclusion Criteria:

• Patients aged 18 to 80 years
• American Society of Anesthesiologists (ASA) physical status I to III
• scheduled for lumbar microdiscectomy surgery

Exclusion Criteria:

• Known allergy to local anesthetics
• Any other significant drug allergies related to the study interventions
• Pregnancy
• Pre-existing psychiatric or neurological disorders
• Inability to provide informed consent

only IPD used in the results publication