Lumbar disc herniation (LDH) is an increasingly common spine disorder . In patients treated surgically, inhalation anesthesia and the use of opioids for analgesic purposes are generally the chosen anesthetic methods. Surgical techniques such as discectomy, microdiscectomy, and stabilization (REF) are used to treat LDH. Although discectomy is considered the primary option in the treatment of LDH, less invasive techniques such as microdiscectomy have been applied in recent years . However, despite the use of less invasive techniques, patients experience pain after surgery . Clinicians want to avoid complications such as thromboembolism and hemodynamic deterioration that may occur due to postoperative pain, and to apply effective pain treatment for patient comfort and rapid discharge from the hospital. It has also been stated that inadequate postoperative pain treatment may increase the risk of developing chronic pain. Therefore, the use of opioids for analgesic purposes in the intraoperative and postoperative periods is quite common. However, opioid use may cause side effects that negatively affect postoperative recovery and may delay discharge. Some of these situations include delayed recovery from anesthesia, failure to perform early postoperative neurological examination due to delayed recovery, postoperative nausea and vomiting (PONV), pruritus, urinary retention, respiratory depression, gastrointestinal dysfunction, and addiction. Another important issue is the difficulty of applying effective treatment to patients, the side effects that develop due to the applied treatments, and the increase in healthcare costs, which are important problems. Therefore, it is also very important to take a cost-effective approach while trying to treat patients at the highest level. The applied anesthesia and analgesia methods can also significantly affect the cost of surgical treatments. In particular, inhalation anesthetics used in patients receiving general anesthesia and opioids used for intraoperative and postoperative analgesia constitute a significant portion of the anesthesia cost. Therefore, strategies that will provide cost savings by reducing the use of both inhalation anesthetics and opioids are emphasized. In this context, nerve blocks or fascial plane blocks applied with local anesthetics come to the fore. With the widespread use of ultrasonography in regional anesthesia practice, regional plane blocks have also become widespread in parallel with this development and have begun to take more place in the literature. Erector spinae plane block (ESPB) is also among these blocks that are increasingly gaining ground in the literature. ESPB is a technique defined for both acute and chronic pain. ESPB is performed by administering local anesthetic (LA) to the fascial plane between the transverse process of the vertebra and the overlying erector spinae muscle. When literature data are examined, ESPB can be applied from the thoracic or lumbar levels in LDH surgery, before and after preoperative anesthesia induction, intraoperatively, at the end of surgery, before extubation or in the postoperative period. ESPB can be applied with the patient in the prone position, sitting or lateral decubitus position. In studies conducted on patients undergoing laparoscopic cholecystectomy, it was found that ESPB reduced the amount of intraoperative inhalation anesthetic and opioid consumption. In another study examining the effect of ESPB on lumbar spine surgeries, it was found that ESPB reduced the use of intraoperative fentanyl and isoflurane and significantly shortened the recovery time. In addition, ESPB is thought to provide more effective analgesia in postoperative pain management and reduce opioid consumption and opioid-related side effects after lumbar spine surgeries. According to the results of published studies, it has been stated that ESPB is more effective for postoperative analgesia in patients undergoing lumbar surgery, significantly reduces pain scores at rest (static) and during activity (dynamic), provides a significant decrease in 24-hour opioid consumption, prolongs the first analgesic requirement period and is associated with fewer side effects. Another important issue is to keep intraoperative hemodynamics stable within normal limits in patients under general anesthesia. Hemodynamic stability is very important to ensure that the amount of bleeding from the surgical site is kept at a minimum level, especially during LDH surgeries. It has been stated that the combined application of regional anesthesia and general anesthesia in spinal surgery provides better pain control as well as better hemodynamic stability. This study aimed to compare the effects of preoperative and intraoperative ESPB on opioid consumption, anesthetic drug consumption, and hemodynamics in LDH surgeries.