Comparing the Postoperative Analgesic Effects of Bupivacaine Liposome Serrate Anterior Plane Block (SAPB) Versus Traditional Thoracic Paravertebral Block (TPVB): A Randomized, Double-blinded Non-inferiority Clinical Trial

Extensive research suggests that paravertebral block can replace thoracic epidural anesthesia as the "gold standard" for thoracic surgery pain relief. However, this technique is more challenging than the fascial plane block and carries the risk of damaging the pleura or spinal nerve roots. The serratus anterior plane block (SAPB) was refined by Blanco et al. in 2013 and is a new, safe regional anesthesia technique that can block the lateral cutaneous branches of the intercostal nerves from T2 to T9, as well as the long thoracic nerve, providing intraoperative and postoperative pain relief for surgeries in this area. A meta-analysis has reported that it can be an alternative regional anesthesia method to paravertebral and intercostal nerve blocks, and is technically safer, more effective, easier to perform, and may have fewer adverse reactions, making it more favored by clinicians. However, a recent network meta-analysis of regional block techniques in thoracic surgery suggested that, in terms of postoperative pain scores at 24 hours, SAPB can relieve pain but is slightly inferior to paravertebral block.

The duration of action of currently used local anesthetics is short. Although various adjuvants have been proposed, such as dexamethasone and dexmedetomidine, there are currently no drugs approved by the FDA that reliably extend the duration of local anesthetics beyond 24 hours (PMID: 27749354). Liposomal encapsulation of bupivacaine can extend the release time of local anesthetics to 72-96 hours (PMID: 23229686, 28120158), with the potential to reduce pain scores at 72 hours postoperatively (PMID: 22067185). Liposomal bupivacaine (Hengrui, Jiangsu) is also the first long-acting local anesthetic currently on the market in China, sparking new hope for anesthesiologists to better manage postoperative pain.

This study hypothesizes, from a clinical perspective, that the use of long-acting local anesthetic liposomal bupivacaine in a simplified and safe serratus anterior plane block technique for regional pain relief postoperatively is not inferior to the widely accepted gold standard for thoracic pain relief-paravertebral block with ropivacaine.