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In the ESPB group, the probe was placed longitudinally at the level of the T5 transverse process, 2-3 cm lateral from the midline. The muscles were visualized superior to the transverse process ; then, the needle was inserted in the craniocaudal direction using the in-plane technique. A dose of 2 mL normal saline were injected into the two layers of the interfacial area under the erector spinae muscle, and the proper injection site was confirmed. After visualizing the linear spread of saline in the fascial plane, 20 mL of 0.25% bupivacaine was injected there for the block.

In the TPVB group, the probe was placed 2-3 cm laterally and vertically of the T5 spinous process. Once the transverse process, corresponding paravertebral space, internal intercostal membrane, and pleura was identified , the needle was inserted in the lateromedial direction using the in-plane technique. After confirmation of pleural displacement with 2 mL saline, 20 mL of 0.25% bupivacaine was administered for the block.