Bilevel Erector Spinae Plane Block Versus Transversus Abdominis Plane Block for Analgesia After Cesarean Delivery.

In the ESP group, patients will be positioned in the right lateral position. The ultrasound probe will be placed vertically about 3 cm lateral to the spinous process of T9 to visualize the transverse process, trapezius, and erector spinae muscles. A 22-gauge spinal needle will be inserted in-plane in the cranial-to-caudal direction until the needle tip reaches the fascial plane between the erector spinae muscle and transverse process. Following hydrodissection with 2 mL of sterile saline to confirm needle placement, and negative aspiration to rule out intravascular placement, the local anesthetic will be injected. Likewise, the same block procedure will be performed at the T11 level and on both levels on the other side, 10 mL will be injected at each of the four injection sites.

In the TAP group, patients will be positioned in the supine position. A posterior approach will be employed, with the ultrasound probe placed transversely on the anterolateral abdominal wall, midway between the costal margin and iliac crest, posterior to the midaxillary line. This will allow visualization of the external oblique, internal oblique, and transversus abdominis muscles. The probe will then be moved posteriorly to identify the tapering of the transversus abdominis muscle toward the quadratus lumborum. A 22-gauge spinal needle will be inserted in-plane from anterior to posterior. Following hydrodissection with 2 mL of sterile saline to confirm needle placement, and negative aspiration to rule out intravascular placement, the local anesthetic will be injected into the plane between the internal oblique and transversus abdominis muscles. Likewise, the same block procedure will be performed on the other side.

A total of 20 mL of 0.25 bupivacaine will be administered at each side.