Dual Approach External Oblique Fascial Plane Block Versus Erector Spinae Plane Block for Post Operative Analgesia in Percutaneous Nephrolithotomy

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• **Detailed Description**

This prospective, randomized, double-blind controlled clinical study is designed to compare the postoperative analgesic efficacy of two ultrasound-guided regional anesthesia techniques-the dual-approach external oblique fascial plane block and the erector spinae plane block-in adult patients undergoing percutaneous nephrolithotomy (PCNL).

Eligible patients aged 18-65 years with American Society of Anesthesiologists (ASA) physical status I or II, scheduled for unilateral PCNL under general anesthesia, will be enrolled after obtaining written informed consent. Participants will be randomly allocated in a 1:1:1 ratio into three groups: one group receiving the dual-approach external oblique fascial plane block, a second group receiving the erector spinae plane block, and a control group receiving general anesthesia alone according to the institutional standard analgesic protocol. Randomization will be performed using a computer-generated sequence, with allocation concealment ensured by sealed opaque envelopes. Outcome assessors and data analysts will be blinded to group allocation.

All patients will receive standardized general anesthesia. The regional blocks, when assigned, will be performed under ultrasound guidance using local anesthetic within safe dosage limits, following aseptic precautions. The dual-approach external oblique fascial plane block will involve injections at both the lateral abdominal wall and costal margin, while the erector spinae plane block will be performed at the thoracic paraspinal level. No regional anesthesia technique will be administered to patients in the control group.

Postoperative pain will be evaluated using the visual analog scale (VAS) at predefined time points during the first 24 hours after surgery. The primary outcome measure is postoperative pain intensity as assessed by VAS. Secondary outcome measures include total opioid (nalbuphine) consumption during the first 24 hours, intraoperative nociceptive responses as reflected by changes in heart rate and mean arterial pressure, patient satisfaction with pain management, and the incidence of block-related or anesthesia-related complications.

Rescue analgesia will be administered according to a predefined protocol when pain scores exceed the accepted threshold. All adverse events and complications related to the regional anesthesia techniques or general anesthesia will be monitored and documented throughout the intraoperative and postoperative periods.

The findings of this study are expected to clarify the relative effectiveness and safety of these two interfascial plane blocks for postoperative pain management following PCNL and may help guide clinical practice in regional anesthesia for urologic surgery.

Inclusion criteria

• Age between 18 and 65 years
• American Society of Anesthesiologists (ASA) physical status I or II

Body mass index (BMI) between 18 and 35 kg/m²

Scheduled for unilateral percutaneous nephrolithotomy (PCNL)

Ability to understand the study protocol and provide written informed conse

Exclusion criteria

Refusal to participate

Known allergy or hypersensitivity to local anesthetics

Infection at the site of block injection

Coagulopathy or bleeding disorders

Chronic pain syndrome or long-term opioid use

Severe hepatic, renal, or cardiac disease

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