Erector Spinae Plane Block Versus Intrathecal Morphine for Post-Cesarean Analgesia Within an Enhanced Recovery Protocol: A Randomized Controlled Trial

Background: Optimal post-cesarean analgesia is essential for successful Enhanced Recovery After Surgery (ERAS) protocols. While intrathecal morphine remains the gold standard, its adverse effects limit widespread use. The erector spinae plane (ESP) block has emerged as a promising opioid-sparing alternative. This study compared the analgesic efficacy and safety profile of ESP block versus intrathecal morphine in a multimodal ERAS pathway. Methods: This prospective, randomized, single-blind study enrolled 140 parturients undergoing elective cesarean delivery under spinal anesthesia at a tertiary care center in Algeria (February 2023–December 2024). Patients were randomly allocated to receive either bilateral ESP block at T9 with 20 mL of 0.25% bupivacaine per side (ESP group, n=70) or intrathecal morphine 100 μg (Morphine group, n=70). Both groups received standardized multimodal analgesia with paracetamol and nefopam. Primary outcome was time to first analgesic request. Secondary outcomes included visual analog scale (VAS) scores at rest and during mobilization, rescue analgesic consumption, adverse effects, maternal satisfaction, and length of hospital stay. Multivariate analyses identified independent predictors of analgesic requirements. Results: The ESP group demonstrated significantly prolonged time to first analgesic request compared to the Morphine group (median 16h vs 6h; mean 16.88±5.09h vs 6.86±3.43h; p