Addition of Liposome Bupivacaine in Interscalene Brachial Plexus Block Lowers Postoperative Pain Up to 1 Week After Rotator Cuff Surgery

> Introduction
Surgical repair of the rotator cuff is frequently associated with significant pre- and postoperative pain. Dexamethasone and clonidine have been used in interscalene brachial plexus block (ISBPB) to extend the duration of analgesia, yet these additives are not FDA approved and have not been consistent in prolonging relief from postoperative pain. Liposome bupivacaine (LB) is a novel drug delivery system designed for gradual release of the local anesthetic bupivacaine. We examined the efficacy of LB in ISBPB to provide analgesia for pain at rest and with movement in the first postoperative week after rotator cuff surgery.

> Materials and methods
In this Ethics Committee approved single-center, double-blind study, 40 patients having rotator cuff repair were randomized to receive either ISBPB with a mixture of 10 mL LB 1.33% and 5 mL Bupi 0.25% (LB+Bupi) or 15 mL Bupi 0.25% (Bupi alone). All patients received standard multimodal postoperative analgesia. Numeric Rating Scale (NRS) scores were obtained for pre- and postoperative pain at rest and with movement of the shoulder. Differences from preoperative pain were calculated for postoperative 36, 48, 72, 96 h and for 7 d. Repeated measures regression techniques were used to account for the effect of time.

> Results
As would be expected at baseline, mean NRS scores for pain with movement (Bupi 5,85 ; LB+Bupi 6,5) were higher than mean NRS scores for pain at rest (Bupi 2,8 ; LB+Bupi 3,4). Pain at rest and with movement decreased and remained lower for the LB+Bupi group compared to the Bupi alone group through the first postoperative week (group differences over time, p = 0.02 for rest and p = 0.01 for movement). While rest and movement pain scores appeared to stabilize at lower values for the LB+Bupi group, there was a suggestion of a rebound effect for pain at rest beginning at 48 h for patients in the Bupi alone group.

> Conclusions : 
The addition of LB to bupivacaine appears to reduce pain in the first postoperative week in patients given ISBPB for rotator cuff repair. The efficacy of LB was shown in patients given standard multimodal postoperative analgesia for their surgeries, and was shown for both pain at rest and with movement.

Addition of liposome bupivacaine in interscalene brachial plexus block lowers postoperative pain up to 1 week after rotator cuff surgery