Effective control of postoperative pain following pediatric lower urogenital surgery is important for enhancing recovery and reducing opioid requirements. Anterior quadratus lumborum block and retrolaminar block are two ultrasound-guided truncal block techniques used for perioperative analgesia in lower abdominal surgery. However, direct comparisons of their analgesic efficacy in pediatric lower urogenital procedures remain limited.

This prospective, randomized, controlled trial will enroll 76 pediatric patients aged 6 months to 12 years with American Society of Anesthesiologists physical status I-III who are scheduled for elective lower urogenital surgery. Participants will be randomly assigned in a 1:1 ratio to receive either an anterior quadratus lumborum block or a retrolaminar block. Both techniques will be performed under ultrasound guidance in addition to standardized general anesthesia.

The primary outcome will be rescue analgesic requirement during the first 24 postoperative hours. Secondary outcomes will include postoperative pain scores, time to first rescue analgesic administration, intraoperative remifentanil consumption, adverse effects such as nausea and vomiting, and caregiver satisfaction. The study aims to compare the postoperative analgesic efficacy and safety of anterior quadratus lumborum block and retrolaminar block in pediatric patients undergoing lower urogenital surgery.

Effective postoperative pain control following pediatric lower urogenital surgery is essential for improving recovery, reducing distress, facilitating oral intake, and decreasing opioid consumption. Ultrasound-guided regional anesthesia techniques have become an important component of multimodal analgesia strategies in pediatric anesthesia. Anterior quadratus lumborum block and retrolaminar block are two truncal block techniques used to provide analgesia for lower abdominal surgical procedures. However, direct comparisons of the postoperative analgesic efficacy of these techniques in pediatric lower urogenital surgery remain limited.

The aim of this study is to compare the postoperative analgesic efficacy of anterior quadratus lumborum block and retrolaminar block in pediatric patients undergoing lower urogenital surgery. Secondary objectives include evaluation of rescue analgesic requirements, postoperative pain scores, time to first rescue analgesic administration, intraoperative opioid consumption, adverse effects, and caregiver satisfaction.

This study is designed as a prospective, randomized, controlled, assessor-blinded clinical trial involving pediatric patients aged 6 months to 12 years with American Society of Anesthesiologists physical status I to III who are scheduled for elective lower urogenital surgery. Eligible participants will be randomly assigned in a 1:1 ratio to either the anterior quadratus lumborum block group or the retrolaminar block group using a computer-generated randomization sequence. Allocation concealment will be maintained using sequentially numbered opaque sealed envelopes.

All patients will receive standardized general anesthesia. Following induction of anesthesia, regional blocks will be performed under sterile conditions with ultrasound guidance. In both groups, 0.25 percent bupivacaine will be administered at a volume of 0.4 milliliters per kilogram.

Intraoperative monitoring will include heart rate and arterial blood pressure measurements recorded at baseline and predefined time points during surgery. If either parameter increases by 20 percent or more compared with baseline values, remifentanil infusion will be initiated and total remifentanil consumption will be recorded.

Postoperative pain assessment will be performed using the Face, Legs, Activity, Cry, and Consolability Scale. This scale ranges from 0 to 10 points, with higher scores indicating greater pain intensity. Rescue analgesia will be administered when the score is 4 or higher.

Patients will be evaluated in the post-anesthesia care unit and during ward follow-up at predefined time points. Pain scores, total rescue analgesic consumption, time to first rescue analgesic administration, adverse events including postoperative nausea and vomiting, and caregiver satisfaction will be recorded.

The primary outcome measure is total rescue analgesic requirement during the first 24 postoperative hours. Secondary outcome measures include postoperative pain scores, time to first rescue analgesic administration, intraoperative remifentanil consumption, incidence of postoperative nausea and vomiting, block success, and caregiver satisfaction.

Based on the sample size calculation, a total of 76 patients will be enrolled. Statistical analyses will be performed using appropriate parametric or nonparametric methods, and a p value less than 0.05 will be considered statistically significant.

Inclusion Criteria:

• Age between 6 months and 12 years
• Scheduled for lower abdominal urogenital surgery (e.g., inguinal hernia repair or orchiopexy for undescended testis)
• American Society of Anesthesiologists physical status classification I-III
• Written informed consent obtained from a parent or legal guardian

Exclusion Criteria:

• History of allergy to local anesthetic agents
• Presence of infection at the planned injection site
• Coagulopathy or any other condition contraindicating regional anesthesia
• Planned laparoscopic orchiopexy
• American Society of Anesthesiologists physical status classification IV
• Inability to obtain informed consent from a parent or legal guardian
• Anticipated requirement for postoperative intensive care unit admission

The anesthesiologist responsible for evaluating eligibility criteria, monitoring intraoperative and postoperative pain scores and analgesic consumption, collecting study data, and performing statistical analyses will be blinded to group allocation. Participants and their caregivers will also remain blinded throughout the study. Randomization will be conducted by an independent investigator who will not be involved in patient recruitment, block performance, perioperative management, outcome assessment, or data analysis. Due to the nature of the interventions, the anesthesiologist performing the regional block procedures will be aware of group allocation and cannot be blinded. This anesthesiologist will not participate in postoperative assessments, data collection, or statistical analyses. Postoperative pain assessments on the ward will be performed every 4 hours by blinded nursing staff using the Face, Legs, Activity, Cry, and Consolability Scale. Patients with a score of 4 or greater w