T1 Paravertebral Block Without Ventral Pleural Shift Resembles Intertransverse Process Block With Reduced Sympathetic Blockade: A Case Series.

Although T1-level paravertebral block (T1PVB) may provide both stellate ganglion and partial brachial plexus blockade, its deep anatomical location makes the procedure technically demanding. We retrospectively analyzed 54 of 65 ultrasound-guided T1PVB procedures performed in 11 patients, in which ventral shift of the pleura (VSP) could be evaluated. Procedures with VSP showed more frequent Horner's sign and greater ipsilateral upper-limb temperature increases than those without VSP. These findings suggest that T1PVB without VSP may functionally resemble intertransverse process block (ITPB), whereas real-time confirmation of VSP during T1PVB may indicate more effective sympathetic blockade.