Neurotoxicity of bupivacaine and liposome bupivacaine after sciatic nerve block in healthy and streptozotocin-induced diabetic mice

Background Diabetes mellitus and the associated neuropathic complications have become a steadily increasing global health burden. Diabetic patients are estimated to require surgery at least twice as often as nondiabetic patients. Neuropathy may change the way nerves respond to nerve blocks. There is currently no consensus on whether regional anaesthesia techniques should be adopted in these patients. Long-acting local anaesthetics ( e.g . bupivacaine HCl) or sustained-release formulations of bupivacaine ( e.g . liposomal bupivacaine) could prove neurotoxic in the presence of diabetic neuropathy. The aim of the study was to assess neurotoxicity of liposome bupivacaine in streptozotocin (STZ)-induced diabetic mice after sciatic nerve block using a reduction in fibre density and decreased myelination assessed by G-ratio as an indicator of local anaesthetic neurotoxicity. Results Prior to performing sciatic nerve block, higher levels of fasting glucose were recorded in diabetic mice compared to nondiabetic mice ( P < 0.001). Likewise, significant differences were noted in the tail flick and plantar test thermal latencies between the groups ( P < 0.001) which confirmed the presence of peripheral sensory neuropathy in diabetic mice. In both, diabetic and nondiabetic mice, sciatic nerve block with 0.25% bupivacaine HCl resulted in a significantly greater G-ratio (axon diameter/large fibre diameter) and an axon diameter compared to nerves treated with 1.3% liposomal bupivacaine or saline (0.9% sodium chloride) ( P < 0.01 ). Moreover, sciatic nerve block with 0.25% bupivacaine HCl resulted in higher fibre density and large fibre and axon diameters compared to the control (untreated) sciatic nerves in both STZ-induced diabetic ( P < 0.05 ) and nondiabetic mice ( P < 0.01 ). No evidence of acute or chronic inflammation was observed in any of the treatment groups. Conclusions Under the conditions of this study, sciatic nerve block with bupivacaine HCl, but not liposome bupivacaine or saline, resulted in histomorphometric indices of neurotoxicity. The presence of diabetes did not appear to affect the severity of the histologic findings.

Patient Complications after Interscalene Block: A Retrospective Comparison of Liposomal Bupivacaine to Nonliposomal Bupivacaine

Background. The purpose of this study was to investigate if the addition of liposome bupivacaine (LB) to an interscalene block (ISB) had an effect on the number of patients with surgical- or block-related complications. Methods. This was a single-center retrospective chart view performed by identifying patients who received an ISB from January 1, 2014, through April 26, 2018, at the University of Minnesota. 1,518 patients were identified who received an ISB (LB = 784, nonliposomal bupivacaine = 734). Patients were divided into two groups those who did receive liposome bupivacaine in their ISB and those who did not receive liposome bupivacaine in their ISB. Medical records were individually reviewed for surgical procedure, block medications, complications related to the block or surgical procedure, phone calls to the healthcare system for issues related to opioids or pain within 3 and within 30 days, readmissions within 30 days, and emergency room visits for complications within 3 and 30 days. Results. There was no significant difference in the number of patients with surgical or anesthetic complications. Only phone calls for pain within 3 days were significantly different. The LB group had 3.2% of patients call compared to 5.6% in the nonliposomal bupivacaine group (aOR = 1.71 (95% CI: 1.04–2.87), p=0.036). We found no significant difference in any of the other secondary outcomes. Conclusions. The use of LB in an ISB demonstrated no significant difference compared to nonliposomal bupivacaine in numbers of complications, emergency room visits, and readmissions.

Patient Complications After Interscalene Block: A Retrospective Comparison of Liposomal Bupivacaine to Non-Liposomal Bupivacaine.

Background The purpose of this study was to investigate if the addition of liposome bupivacaine (LB) to an interscalene block (ISB) had an effect on the number of patients with surgical or block related complications.Methods This was a single-center retrospective chart view was performed identifying patients who received an ISB from January 1, 2014 through April 26, 2018 at the University of Minnestoa. 1,518 patients were identified who received an ISB (LB =784, non-liposomal bupivacaine =734). Patients were divided into two groups those who did receive liposome bupivacaine in their ISB and those who did not receive liposome bupivacaine in their ISB. Medical records were individually reviewed for surgical procedure, block medications, complications related to the block or surgical procedure, phone calls to the healthcare system for issues related to opioids or pain within 3 and within 30 days, readmissions within 30 days, and emergency room visits for complications within 3 and 30 days.Results There was no significant difference in the number of patients with surgical or anesthetic complications. Only phone calls for pain within 3 days was significantly different. The LB group had 3.2% of patients call compared to 5.6% in the non-liposomal bupivacaine group (aOR=1.71 [95% CI: 1.04-2.87], p=0.036). We found no significant difference in any of the other secondary outcomes.Conclusions The use of LB in an ISB demonstrated no significant difference compared to non-liposomal bupivacaine in numbers of complications, emergency room visits, and readmissions.