To compare the efficacy and safety of ultrasound-guided ESPB versus QLB for post-operative analgesia in children undergoing kidney surgery.

The management of postoperative pain in pediatric kidney surgery is a critical component of enhanced recovery and improved patient outcomes. Effective analgesia minimizes opioid consumption and their associated side effects, facilitating early mobilization and discharge. Regional anesthesia techniques have gained prominence as opioid-sparing modalities in pediatric patients, with the erector spinae plane block (ESPB) and quadratus lumborum block (QLB) increasingly used in abdominal and renal surgeries.

The erector spinae plane block is a fascial plane block targeting the dorsal rami of spinal nerves, providing extensive analgesia for thoracic and abdominal procedures. It is considered relatively easy and safe to perform under ultrasound guidance and has been associated with effective postoperative analgesia and reduced opioid requirements in pediatric renal surgery. Additional advantages include shorter block performance time and a lower incidence of postoperative nausea and vomiting compared with other regional techniques.

The quadratus lumborum block involves local anesthetic deposition near the quadratus lumborum muscle and can be performed using different approaches, such as anterior and transmuscular techniques. These approaches provide both somatic and visceral analgesia for lower abdominal and renal surgeries. Continuous quadratus lumborum block has demonstrated effective postoperative pain control, reduced need for rescue analgesia, and minimal adverse events in pediatric renal procedures. It is also recognized for its favorable safety profile and its contribution to improved quality of recovery.

Although both ESPB and QLB are effective regional techniques for pediatric postoperative analgesia, studies comparing their efficacy have reported variable results. Some investigations have shown comparable pain scores and opioid consumption between the two blocks, while others suggest potential advantages of one technique over the other in terms of analgesic duration, side-effect profile, or patient satisfaction.

Pain assessment in pediatric patients remains challenging because of differences in age, cognitive development, and communication abilities. This necessitates the use of objective pain scoring systems and careful perioperative analgesic planning. Consequently, evaluating and comparing the analgesic efficacy and safety of these two regional blocks in pediatric kidney surgery is of particular clinical importance.

The rationale of this study is to provide direct comparative evidence on the effectiveness and safety of ultrasound-guided ESPB versus QLB for postoperative analgesia in pediatric kidney surgery. Clarifying which technique offers superior analgesic control with fewer side effects may help optimize perioperative pain management protocols and improve postoperative outcomes. This study aims to assess postoperative pain scores, opioid consumption, block-related complications, and recovery quality in order to guide anesthetic decision-making in pediatric renal surgery

Inclusion Criteria:

Children of both sexes, aged 2-12 years, with ASA physical status I-II scheduled for elective unilateral kidney surgery will be eligible.

Exclusion Criteria:

• Infection at the site of needle insertion
• Allergy to local anesthetics
• Parental refusal of consent