Addition of Exparel® to Bupivacaine Hydrochloride results in similar early block characteristics but significantly longer analgesia in patients with rotator cuff repair.

Cédric Bouts, Ine Leunen, Jeroen Boons, Steven Dewaele, Dimitri Dylst,  Catherine Vandepitte
Department of Anesthesiology, Intensive Care, Emergency Medicine and Pain Therapy, Ziekenhuis Oost-Limburg Genk, Belgium

Background and Goal of Study
A recent introduction of liposomal bupivacaine 1,3% (Exparel®) in the clinical practice of regional anesthesia in the USA represents a major pharmacological advance. Several studies have documented the analgesic benefit of Exparel®.1, 2, 3 We tested the hypothesis that addition of Exparel® to Bupivacaine Hydrochloride (Bupi HCl) results in similar early block characteristics, but longer duration of analgesia than Bupi HCl alone. 

Material and Methods
After local ethics committee and Belgian NDA approval (NCT02554357), forty subjects were randomized to receive an interscalene brachial plexus block (ISB) with either 15 ml Bupi HCl 0.25% alone or 5 ml Bupi HCl 0.25% followed by 10 ml Exparel® under ultrasound guidance. The main outcome variables were postoperative pain and opioid consumption. All patients received general anesthesia for surgery and were assessed by a blinded observer up to one week postoperatively. 

Results and Discussion
As part of a data entry check, a preliminary analysis of NRS pain scores was conducted on Exparel® (n = 9) and Bupi HCl (n = 8) patients. Pain scores at rest and with movement at 36h, 48h, 60h, 72h, 84h, 96h and 7d were consistently lower for Exparel® by approximately 1-2 points. When pain was dichotomized at 3 (0-3 v 4-10), Fisher’s exact p-values suggested that differences would be most evident from 48-60h onward. Sensory blockade was stronger in the Bupi HCl group than in the Exparel® group at 30min (3.4 v 6.0, respectively, p = 0.09); however, there was no difference in sensory blockade between the groups at 1h postoperatively (3.9 v 4.6, respectively, ns). None of the patients had signs of shortness of breath (phrenic paralysis), local anesthetic toxicity or prolonged motor blockade. 

Conclusion
An interim analysis of our study suggests that addition of Exparel® to Bupi HCl results in similar early block characteristics, but significantly longer duration of analgesia than Bupi HCl alone. 

 1 Knee. 2012 19(5): 530-6
 2 Best Pract Res Clin Anaesthesiol. 2014 28(1): 15-27
 3 Clin Drug Investig. 2013 33 (2): 109-15

Addition of Exparel® to Bupivacaine Hydrochloride results in similar early block characteristics but significantly longer analgesia in patients with rotator cuff repair