Thoracic paravertebral block vs. mid-point transverse process to pleura block in thoracic surgery. Preliminary evaluation of effectiveness and safety

Mid-point transverse process to pleura block (MTPB) is an alternative approach to paravertebral block. We retrospectively assessed hemodynamic stability, inadvertent pleural puncture and antalgic effectiveness of this approach compared with traditional paravertebral block. Moreover, being used to add methylene bleu to local anesthetic solution as a tracer, we compared the diffusion pattern in paravertebral space of the two techniques. We reported retrospectively 40 patients underwent lung lobectomy from July to October 2021 in Monaldi Hospital (Naples, Italy) receiving thoracic paravertebral block (n=20) or mid-point transverse process to pleura block (n=20). The primary outcomes were a 20% mean arterial pressure variation from the base line, chest wall or pleural hematoma and technique failure. Analgesic effectiveness was assessed comparing remifentanil consumption to keep nociception index level <25 and patient’s visual analog scale (VAS) in post anesthesia care unit or daycare surgical unit at 60’. Also the methylene blue spread was assessed by a surgeon, blinded to patient’s name, reviewing surgery videorecord of every cases. MAP decrease >20% was greater in the thoracic paravertebral block (TPVB). No significative differences were reported for pleural punctures, chest wall hematomas or failure of the technique in the two groups. Methylene blue was evident in all patients of the TPVB, while it was not visible in any of the patients of the MTPB group. Remifentanil consumption, nociception index level and postoperative 60’ VAS were greater in the MTPB. Antalgic power and local anesthetic spread of TPVB seems to be superior to the MTPB, even if the safety profile of the latter seems to be better. Due to the retrospective nature of the study and the small number of cases in the sample, further studies are needed.