A Comparison of Liposomal Bupivacaine Versus Ropivacaine for Interscalene Brachial Plexus Block in Alleviating Rebound Pain Following Shoulder Arthroscopy

Shoulder arthroscopy represents a frequently employed orthopedic procedure for managing a wide spectrum of pathologic shoulder conditions, including rotator cuff tears, glenohumeral instability, and stiffness. Despite its minimally invasive nature, postoperative pain remains a frequent and significant concern. Effective perioperative analgesia is crucial to facilitating early mobilization and functional recovery . For this purpose, the interscalene brachial plexus block (ISBPB) remains the gold standard for postoperative pain control following arthroscopic shoulder surgery. It is easy to perform and demonstrates a favorable side effect profile. Nonetheless, the pain duration of a single-injection ISBPB is often less than 24 hours, even with long-lasting local anesthetics such as bupivacaine and ropivacaine[6]. Rebound pain following the resolution of the block poses a major challenge to the effectiveness of peripheral nerve blocks for postoperative analgesia.

Rebound pain is defined as a marked exacerbation of pain, characterized by an abrupt transition from well-controlled pain (Numerical Rating Scale, NRS ≤ 3) during the period of the block efficacy to severe pain (NRS ≥ 7) within 24 hours after peripheral nerve blockade. Reported incidence rates range from 35% to 62% , with a higher prevalence following orthopedic procedures-particularly those involving the shoulder and knee-where its frequency is 1.8 times greater compared with soft tissue operations. This rapid shift from minimal pain to intense discomfort not only disrupts sleep and impedes functional recovery, but may also negate the perioperative analgesic benefits afforded by regional anesthesia . Consequently, developing effective strategies to prevent rebound pain is critically important.

A variety of adjuncts have been evaluated to extend the duration of postoperative analgesia, with the goal of enhancing pain control and mitigating rebound pain; however, the extension of analgesia remains modest and the overall clinical benefit uncertain. While continuous peripheral nerve catheters represent an alternative means to prolong analgesia, their use is limited by technical complexity, resource intensity, and an increased risk of complications such as dislodgement or infection.

Liposomal bupivacaine, a multivesicular formulation engineered to provide sustained and controlled release of bupivacaine, has been developed to prolong analgesic duration and reduce rebound pain. Nevertheless, its efficacy in peripheral nerve blocks remains a subject of considerable debate. Multiple studies have reported that perineural administration of liposomal bupivacaine for interscalene brachial plexus block fails to significantly improve postoperative pain scores or reduce opioid consumption after shoulder surgery compared with conventional local anesthetics. Therefore, we conducted a randomized controlled trial with blinding of patients and outcome assessors to evaluate whether liposomal bupivacaine, when administered via interscalene brachial plexus block, reduces rebound pain more effectively than ropivacaine in patients undergoing arthroscopic shoulder surgery.