The Effects of Extracorporeal Shockwave on Liposomal Bupivacaine

Introduction: Multivesicular liposomal bupivacaine is effective as a regional anesthetic following stifle stabilization procedures. Extracorporeal shockwave therapy (ESWT) has been shown to hasten radiographic osteotomy healing following tibial plateau levelling osteotomy. The objective of this study was to evaluate the effect of ESWT on liposomal bupivacaine.

Materials and Methods: A control group and three treatment groups of 10 samples each were defined as follows: (A) E3, 360 shocks/minute (s/m); (B) E6, 360 s/m; (C) E8, 480 s/m. Two cc aliquots of liposomal bupivacaine were placed in a gelatin chamber and treated with shockwave according to group. Free bupivacaine concentrations were determined following treatment using HPLC. Treatment group medians were compared with controls using a nonparametric multiple comparison test (Steel method) with p < 0.05.

Results: The free bupivacaine in all samples was reported, control: 1.90 mg/mL; (A) 2.10 mg/mL, (B) 2.03 mg/mL; (C) 4.35 mg/mL. Only group C was statistically significantly different from the control group (p = 0.0005).

Discussion/Conclusion: The effect of ESWT on multivesicular liposomal bupivacaine was found to be dose dependent in this study. Our study suggests that there was no significant release of bupivacaine from multivesicular liposomes when ESWT was applied at currently recommended, therapeutic settings. However, when energy and frequency settings are increased, there was significant premature release of bupivacaine.

Acknowledgment: Pulse Veterinary Technology provided ESWT trodes, and Richard Evans performed statistical analysis for this project.