Comparison Between Erector Spinae Plane Block vs Transversus Abdominis Plane Block for Postoperative Analgesia in Cesarean Section

For the ESP block, patients will be placed in the right lateral decubitus position, and the T9 transverse process will be identified using a high-frequency linear ultrasound probe positioned 2-3 cm lateral to the midline in a parasagittal orientation. After skin sterilization, a 21-gauge echogenic block needle will be advanced in-plane cranio-caudally until contact with the transverse process is achieved. Hydrodissection with sterile saline will be performed to confirm correct fascial plane placement beneath the erector spinae muscle. A total of 20 mL local anesthetic mixture will be administered on each side, consisting of 10 mL bupivacaine 0.25%- and 10-mL lidocaine 0.5%, ensuring that the maximum safe dose is not exceeded. Correct spread will be confirmed under ultrasound by observing separation of the fascial layers.

For the TAP block, patients will be placed supine, and the posterior approach will be used with the probe placed midway between the subcostal margin and the iliac crest in the anterior axillary line. The fascial plane between the internal oblique and transversus abdominis muscles will be visualized until it tapers toward the quadratus lumborum. A 21-gauge echogenic needle will be introduced in-plane from anterior to posterior, and hydrodissection with sterile saline will be performed to confirm the correct plane. A total of 20 mL local anesthetic mixture will be administered per side, composed of 10 mL bupivacaine 0.25%- and 10-mL lidocaine 0.5%, with care taken to remain within safe dosage limits.