Figure 6 Axial MRI image of the spine showing the injectate spread after TPVB (A), ESPB (B), CTEB (C), and cranio-caudal spread of LA diffusion in the sagittal plane at intercostal space (ICS), thoracic paravertebral space (TPVS) and erector spinae muscle (ESM) in each patient (D). (A) Axial view of T5 vertebra, injectate dispersed into the ICS and TPVS in TPVB. (B) The injectate spread within the ESM in ESPB. (C) In CTEB, injectate was seen spreading to the ICS, the neural foramen, and the ESM at T5. (D) The LA distribution was mainly confined to the thoracic vertebral levels when patients received TPVB or ESPB. While the LA was detected from C7 to L1 in patients receiving CTEB. CTEB – combined thoracic paravertebral block and erector spinae plane block; ESPB – erector spinae plane block; LA – local anesthetic; TPVB – thoracic paravertebral block. (Microsoft PowerPoint 2019MSO, version 2303, Microsoft Corporation; Adobe Acrobat Pro DC, version 2015, Adobe Systems Inc.).