This multicenter, randomized, controlled study aims to compare the analgesic efficacy of Quadro Iliac Plane Block (QIPB) and Erector Spinae Plane (ESP) Block in lumbar vertebra surgeries. The study will evaluate postoperative pain management, opioid consumption, side effects, hospital stay duration, and patient satisfaction. Patients scheduled for single-level lumbar disk herniation surgery will be randomized to receive either the QIPB or ESP block before awakening from anesthesia. Pain scores will be measured at multiple postoperative time points, and opioid consumption will be monitored using patient-controlled analgesia (PCA). The study seeks to identify the most effective and safe method for postoperative pain management in lumbar surgeries.

Detailed Description: The purpose of this study is to compare the analgesic efficacy of two commonly used regional anesthesia techniques-Quadro Iliac Plane Block (QIPB) and Erector Spinae Plane (ESP) Block-in lumbar vertebra surgeries. This is a prospective, randomized, controlled, and multicenter trial. The study aims to evaluate the effectiveness of QIPB and ESP blocks in postoperative pain control, opioid consumption, side effects, hospital stay duration, and patient satisfaction. The findings are expected to contribute to identifying more effective and safer methods for postoperative pain management in lumbar spine surgeries.

This study will focus on examining the impact of these two different block techniques on pain scores, particularly during the early postoperative period. By analyzing the potential benefits and limitations of these techniques, the study will aim to provide valuable insights into postoperative pain control. Additionally, a comparative analysis of the feasibility and patient safety of both block techniques will be conducted.

Materials and Methods: Patients aged 18 and above, with ASA scores of I-III, without bleeding diathesis, no history of anticoagulant use, no history of allergies to the medications used, and no history of neuropathic disease, undergoing single-level lumbar disk herniation surgery will be included in the study. Patients will be randomized to receive either ESP or QIP block before awakening post-surgery. Informed consent will be obtained from all participants, and both blocks will be thoroughly explained.

To avoid bias, the study is designed as multicenter, and experienced anesthesiologists will perform the blocks at the end of the surgery, before the patient is awakened.

Block Techniques:

ESP Block: With a linear ultrasound probe in the transverse plane, the transverse process of the L3 vertebra will be identified. A block needle will be advanced under ultrasound guidance, and once the needle touches the transverse process, it will be withdrawn by 1mm, confirmed with sterile saline, and 50 mg (0.25%) bupivacaine will be administered bilaterally.

QIP Block: For patients in a prone position, a low-frequency convex transducer (2-6 MHz) will be placed at the midline at the L3 level in the transverse plane to identify the spinal process. Lateral movement will identify the transverse process within the erector spinae muscle. The transducer will then be rotated to the parasagittal plane and moved caudally to locate the attachment of the Quadratus Lumborum Muscle (QLM) to the iliac crest. A block needle will be advanced under ultrasound guidance, and 50 mg (0.25%) bupivacaine will be injected bilaterally into the fascia below the QLM.

Postoperative Care: Before awakening, all patients will receive 1g of paracetamol, 100mg of tramadol, and 50mg of dexketoprofen intravenously. Postoperatively, multimodal analgesia will be provided using patient-controlled analgesia (PCA) with tramadol HCl, set to deliver 20 mg boluses with a lockout interval of 20 minutes, and a maximum dose limit of 200mg over 4 hours. Pain scores will be assessed at rest and with movement at 0, 2, 6, 12, and 24 hours using the Numeric Rating Scale (NRS), ranging from 0-10. Opioid consumption and the need for rescue analgesia (50 mg dexketoprofen in 100cc saline over 20 minutes) will also be evaluated. Routine administration of 1g of intravenous paracetamol will be given at 6 hours postoperatively.

Sample Size and Statistical Methods: A power analysis with an alpha error of 0.05, power of 0.8, and effect size of 0.8 determined that at least 26 patients per group (total 52) are needed. Accounting for potential errors, 60 patients will be enrolled in the study. Data will be analyzed using IBM SPSS 21. Descriptive statistics will be computed for each variable, with continuous data presented as mean ± standard deviation or median (IQR), and categorical data as frequencies and percentages. The Shapiro-Wilk test will be used to assess normality, and non-parametric tests will be applied if the data are not normally distributed.

Between-group comparisons of continuous data will use independent t-tests or Mann-Whitney U tests, depending on normality. Categorical variables will be compared using the Chi-square test or Fisher's Exact Test. Primary outcomes, including NRS pain scores at rest at 24 hours, will be analyzed using t-tests or Mann-Whitney U tests. Secondary outcomes, such as opioid consumption, nausea, vomiting, and motor block, will be analyzed similarly. Rescue analgesia need will be analyzed with the Chi-square test. A p-value of <0.05 will be considered statistically significant.

This study aims to provide crucial information on the efficacy and safety of both block techniques, potentially improving postoperative pain management practices in lumbar spine surgeries.

Inclusion Criteria:

• Patients aged 18 to 65 years.
• ASA physical status classification I-III.
• Patients scheduled for single-level lumbar disk herniation surgery.
• No history of bleeding diathesis.
• No history of anticoagulant use.
• No known allergies to the medications used in the study (e.g., bupivacaine).
• No history of neuropathic diseases.
• Patients who have provided informed consent to participate in the study.

Exclusion Criteria:

• Patients younger than 18 or older than 65 years.
• ASA physical status classification IV or higher.
• Patients with a history of coagulopathy or bleeding disorders.
• Patients with a history of chronic opioid use or substance abuse.
• Patients with allergies to local anesthetics (e.g., bupivacaine).
• Patients with significant neuropathic conditions or central nervous system disorders.
• Patients with any contraindication to regional anesthesia.
• Pregnant or breastfeeding women.
• Patients unable to provide informed consent.

This study employs a Double-Blind masking approach to minimize bias. Both the patients and the healthcare providers (including postoperative care staff) will be unaware of which block (Quadro Iliac Plane Block or Erector Spinae Plane Block) was administered. The anesthesiologists performing the blocks will be informed of the assigned intervention but will not participate in postoperative care or outcome assessment. The outcome assessors, who will evaluate pain scores, opioid consumption, and other outcomes, will also be blinded to the group allocation to ensure unbiased data collection.