Patients who will undergo herniated disc surgery have serious pain after surgery. In order to minimise this pain and to ensure that they recover more quickly and use less morphine-derived painkillers, we aim to apply two types of painkiller injections before surgery. For this purpose, it is planned to apply painkiller injections on both sides of the level of the herniated disc with sedation before the operation. Afterwards, herniated disc surgery will be performed under general anaesthesia.

Modified thoracolumbar plane block (mTLIP): under ultrasound-guided, the lateral compartment of the longissimus muscle and iliocostal muscle muscles are imagined and the block needle is placed in the interfascial plane of these two muscles and local anesthesic solution is appliced.

• 20 ml of 0.25% bupivacaine will be used on each side (total of 40 ml of 0.25% bupivacaine will be used)
• to be administered only approximately 20-30 minutes before the onset of anaesthesia.
• only once in the preoperative block room approximately 20-30 minutes before induction of anaesthesia
• plane block applications will be performed by anaesthesiologists with at least 5 years of experience
• patients' intraoperative fentanyl consumption, agitation-sedation scores on awakening from anaesthesia, tramadol consumption in the postoperative 24 hours, postoperative VAS pain scores, and side effects such as postoperative nausea-vomiting will be evaluated.
• plane blocks will be applied under ultrasound guidance.
• plane block applications will be performed by anaesthesiologists with at least 5 years of experience
• Postoperative evaluations of patients will be performed face to face. Patients will be routinely administered 1 g paracetamol intravenously at 8 hour intervals in the postoperative period. 100 mg tramadol intravenously will be administered if their pain is above VAS 4 despite this.
• This study was followed up in the neurosurgery unit of SBU Gazi Yasargil Training and Research Hospital.
• Patients were sedated with 1 mg midazolam and 50 mcg fentanyl intravenously in the preoperative preparation room in the operating room and 20 ml of 0.25% bupivacaine was administered bilaterally on each side under ultrasound guidance. After the block application, the patient was taken to the operating room and standard general anaesthesia was applied.

Patients will be monitored for pain and side effects at the neurosurgery unit , 1st hour, 2nd hour, 4th hour, 8th hour and 24th hour in the postoperative period.

- Both plan blocks are applied for analgesia in the postoperative period and aim to reduce opioid consumption in the postoperative period.

Erector spinae plane block (ESP): After determining the vertebral spinal process and trapezius, rhomboid major and erector spinae muscles with ultrasound guidance, the block needle is advanced in the cranio-caudal direction with an in plane approach and local anaesthetic solution is applied to the plane between the erector spinae muscle and the transverse process when the needle rests on the transverse process.

• 20 ml of 0.25% bupivacaine will be used on each side (total of 40 ml of 0.25% bupivacaine will be used)
• to be administered only approximately 20-30 minutes before the onset of anaesthesia.
• only once in the preoperative block room approximately 20-30 minutes before induction of anaesthesia
• plane block applications will be performed by anaesthesiologists with at least 5 years of experience
• patients' intraoperative fentanyl consumption, agitation-sedation scores on awakening from anaesthesia, tramadol consumption in the postoperative 24 hours, postoperative VAS pain scores, and side effects such as postoperative nausea-vomiting will be evaluated.
• plane blocks will be applied under ultrasound guidance.
• plane block applications will be performed by anaesthesiologists with at least 5 years of experience
• Postoperative evaluations of patients will be performed face to face.

Statistical methods / analysis: G-Power version 3.1.9.4 (Universität Kiel, Germany) program was used to calculate the sample size. The two-tailed alpha error was taken as 0.05, power as 0.80 and effect size as 0.8, and based on a previous study the allocation ratio was accepted as N2/N1:1. The minimum number of patients to be included in the study was calculated as 72.

SPSS 16.0 for Windows (SPSS Inc., Chicago, IL, USA) was used for other statistical analyses. Statistical data were expressed as mean and standard deviation, while categorical data were expressed as frequency and percentage. Comparison of categorical data in the groups was done with Chi-square, the results were given as %n. Shapiro-Wilk tests were used to determine if the numerical data fit the normal distribution. While the data fitting the normal distribution were evaluated with the Student's t-test. Mann- Whitney U tests were used to compare the data differ from the normal distribution. p <0.05 was considered statistically significant.

Inclusion Criteria:

• Patients between 18-70 years of age, ASA I-III, scheduled for Lumbar Disc Herniation operation under general anaesthesia.

Exclusion Criteria:

• ASA >III body mass index (BMI) > 35 kg/m2 known allergy to local anaesthetics presence of preoperative chronic pain presence of coagulopathy those who are unable to give written consent non-voluntary patients

Patients to be operated for 1 or 2 level lumbar disc herniation.

• after de-identification; all individual participant data collected during the research and the primary and secondary outcomes of the study.
• data can be shared immediately after publication, no end date set.
• case-by-case basis at the discretion of Primary Sponsor
• data can be access subject to approvals by Principal Investigator (e-mail: fatma.acil@saglik.gov.tr)