Background and objectives: Thoracic paravertebral block (TPVB) can be used for unilateral surgical procedures. Modifications of the classic approach have been proposed to minimize the risk of pleural puncture. In this study, we evaluated the feasibility and success rate of a transverse in-plane ultrasound (US)-guided TPVB with radiologic confirmation of catheter position.
Methods: A total of 36 patients scheduled for unilateral surgery with a TPVB catheter were included in this prospective study. Ultrasonographically, the transverse process of the thoracic vertebra and rib were identified at the appropriate thoracic level. The transducer was moved cranially until an intercostal US view was obtained, indicated by visualization of the parietal pleura. An in-plane needle insertion approach from lateral to medial was used, and a total of 20 mL ropivacaine 0.75% was injected through the needle and a subsequently threaded catheter, while the spread of local anesthetic was observed. Sensory spread of the block was evaluated by loss of cold sensation in the dermatomes. Catheter position was radiologically evaluated with radiopaque dye.
Results: Block success rate was 100%. In all patients, correct radiologic thoracic paravertebral catheter position was confirmed; 1 patient also showed additional epidural spread. The median number of total dermatomal segments with loss of cold sensation was 6. No pneumothorax or contralateral loss of cold sensation occurred.
Conclusion: An in-plane transverse US-guided TPVB using the described technique is feasible and has a high success rate. In all patients, correct catheter position in the thoracic paravertebral space was radiologically confirmed.