Liposomal bupivacaine: a review of a new bupivacaine formulation

Admixture of Liposomal Bupivacaine and Bupivacaine Hydrochloride for Peripheral Nerve Blocks in Adolescents Undergoing Orthopedic Surgery: An Observational Cohort Study

Background/Objectives: In 2021, the Food and Drug Administration approved liposomal bupivacaine injectable suspension for single-dose infiltration in patients ≥ 6 years of age. Liposomal bupivacaine and bupivacaine hydrochloride admixtures may also be administered off-label for pediatric regional anesthesia including peripheral nerve blocks (PNBs). This single-injection, long-acting technique is not well described in pediatrics but may have benefits over traditional continuous catheter-based systems. The purpose of this investigation was to examine an adolescent cohort who received liposomal bupivacaine/bupivacaine hydrochloride PNBs for orthopedic surgery. Methods: Patient, surgical, anesthetic, block characteristics, and post-anesthesia care unit (PACU) outcomes were retrospectively reviewed from February 2020 to June 2024. From February to December 2022, a short follow-up survey was conducted to assess post-discharge patient-reported outcomes. Results: There were 524 liposomal bupivacaine/bupivacaine hydrochloride PNBs (106 upper-extremity and 418 lower-extremity) performed in 374 patients with a mean (standard deviation, range) age of 16 (1.2, 11-17) years. Two unilateral PNBs were performed in 150 (40%) patients to ensure an adequate sensory neural blockade. The interscalene (n = 81, 15%) and adductor canal (n = 140, 27%) blocks were the most common upper- and lower-extremity PNBs, respectively. Intraoperatively, the majority of the cohort (n = 258, 69%) underwent monitored anesthesia care (MAC). No patient required conversion from MAC to general anesthesia due to pain. In PACU, 288 (77%) patients reported no pain. Mild and moderate pain were reported by 56 (15%) and 30 (8%) patients, respectively. No patients developed local anesthetic toxicity. The survey results (n = 66) indicate that the majority of patients (96%) were satisfied with block analgesia postoperatively. Conclusion: Liposomal bupivacaine/bupivacaine hydrochloride PNBs were used successfully in adolescents undergoing a variety of orthopedic surgeries.

Microfluidic Preparation and Evaluation of Multivesicular Liposomes Containing Gastrodin for Oral Delivery across the Blood-Brain Barrier

In this study, multivesicular liposomes (MVLs) were prepared by microfluidic technology and used for delivering gastrodin (GAS), a water-soluble drug, across the blood-brain barrier (BBB). The formulations and preparation parameters in preparing gastrodin multivesicular liposomes (GAS-MVLs) were both optimized. Some properties of GAS-MVLs including morphology, particle size, encapsulation efficiency, and in vitro release were evaluated. An in vitro BBB model was established by coculturing mouse brain endothelial cells (bEnd.3) and astrocytes (C8-D1A). The permeability of GAS-MVLs across the BBB model was evaluated. Finally, the permeability of GAS-MVLs across BBB was evaluated by in vivo pharmacokinetics in mice. The concentrations of GAS in the blood and brain were determined by high-performance liquid chromatography (HPLC), and then brain-targeting efficiency (BTE), relative uptake rate (Re), and peak concentration ratio (Ce) were calculated. The results showed that, using a Y-type microfluidic chip and setting the flow rate ratio of the second aqueous phase to the W/O emulsion phase at 23, with a total flow rate of 0.184 m/s, the prepared GAS-MVLs showed an obvious multivesicular structure and a relatively narrow distribution of particle sizes. The prepared GAS-MVLs were spherical with a dense structure. The average particle size was 2.09 ± 0.17 μm. The average encapsulation rate was (34.47 ± 0.39)%. The particle size of MVLs prepared by the microfluidic method was much smaller than that prepared by the traditional method, which was usually larger than 10 μm. After 6 h from the beginning of the administration, the apparent transmittance of GAS-MVLs in the in vitro BBB model was 67.71%, which was 1.92 times higher than that of the GAS solution. In vivo pharmacokinetic study showed that the intracerebral area under curve (AUC) of GAS-MVLs was 5.68 times higher than that of the GAS solution, and the e peak concentration (Cmax) was 2.036 times higher than that of the GAS solution. BTE was 1.945, intracerebral Re was 5.688, and Ce was 2.036. Both in vitro and in vivo experiment results showed that GAS-MVLs prepared by microfluidic technology in this study significantly delivered GAS across BBB and enriched GAS in the brain. It provides a possibility for brain-targeting delivery of GAS in the prevention and treatment of central nervous system diseases by oral administration and lays the foundation for further development of oral brain-targeted preparations of GAS.

Liposomal Bupivacaine via an Adductor Canal Block Compared to a Peripheral Nerve Catheter and No Block After Total Knee Arthroplasty: A Retrospective Analysis

Background As total knee arthroplasty is one of the most common surgeries in the United States, it is important to identify regional anesthesia methods that optimize patient recovery. This study evaluates the effectiveness of adductor canal (AC) blocks with liposomal bupivacaine (LB) compared to other regional anesthesia techniques. We hypothesized that patients receiving single-shot (SS) AC blocks with LB would have lower postoperative opioid consumption compared to other groups. Methods A retrospective cohort analysis was conducted on patients from a single institution between January 2014 and December 2021. The primary outcome assessed was postoperative opioid use, with secondary outcomes including postoperative pain scores and hospital length of stay. Results The final analysis included 280 patients: 41 received an SS AC block with plain local anesthetic, 76 received a peripheral nerve catheter (PNC) with continuous ropivacaine, 79 received an SS AC block with LB, and 84 received no block. In fully adjusted models, postoperative opioid consumption on day one was significantly lower in the SS AC block with LB group compared to the no block group (b = 23.2, SE = 5.7, p < 0.0001), the PNC group (b = 15.5, SE = 5.7, p = 0.01), and the SS AC block with plain local anesthetic group (b = 18.9, SE = 6.9, p = 0.01). Additionally, hospital length of stay was significantly reduced in the LB group compared to the no block group (b = 1.5, SE = 0.3, p < 0.0001), the PNC group (b = 1.1, SE = 0.3, p < 0.0001), and the SS AC block with plain local anesthetic group (b = 1.5, SE = 0.3, p < 0.0001). Conclusions Patients who received an AC block with LB had higher pain scores on postoperative day 0 (POD0) but required less opioid medication on postoperative day 1 (POD1) and had a shorter hospital stay compared to patients who received other types of AC blocks or no block.

Reduced Opioid Use Among Patients Who Received Liposomal Bupivacaine Brachial Plexus Block for Total Shoulder Arthroplasty

Purpose This retrospective cohort explores the efficacy of regional shoulder blocks using Exparel™ in patients undergoing total shoulder arthroplasty (TSA)/reverse total shoulder arthroplasty (RSA) to reduce total opioid prescription, refills, and length of stay in the acute care setting. Methods Patients who underwent TSA/RSA by a single surgeon in a three-year period were evaluated. Patients in the case group received liposomal bupivacaine 1.3% brachial plexus block while the control group received ropivacaine 0.5% interscalene brachial plexus block. Outcomes of the study included the number of opioids taken, opioids prescribed, and length of hospital stay. Results Thirty-six patients underwent TSA/RSA between January 2017 and March 2020. Patients who received an Exparel brachial plexus block had decreased opioid use within the first 24 hours after surgery compared to the ropivacaine group, 9.00 ± 14.10 and 26.20 ± 24.8 morphine milligram equivalent (MME), respectively (p=0.0213). Patients who received an Exparel brachial plexus block had decreased opioid prescriptions over the entire postoperative follow-up, 411.00 ± 200.74 MME in the case group and 593.07 ± 297.57 MME in the control group (p=0.0314). Lastly, patients who received an Exparel brachial plexus block had a shorter length of hospital stay, 1.28 ± 0.91 days as compared to the control group's 2.15 ± 1.49 days (p=0.0451). Conclusion This study demonstrates a significant reduction in opioid prescribing and use in patients who receive Exparel brachial plexus nerve blocks compared to non-liposomal local anesthetics, as well as a significant reduction in the length of hospital stay. The data suggest that Exparel use may decrease the risks associated with opioid use while providing adequate analgesia in patients undergoing shoulder arthroplasty.

Bibliometric and visual analysis of research on analgesia and total knee arthroplasty from 1990 to 2022

Background

In recent decades, there have been notable advancements in the field of analgesia and total knee arthroplasty (TKA). This study aims to employ bibliometric analysis to elucidate the prevailing research focal points and trends within analgesia and TKA from 1990 to 2022.

Material and methods

Relevant publications were retrieved from the Web of Science Core Collection. CiteSpace, VOSviewer, and Scimago Graphica were used for visualization and bibliometric analysis of countries, institutions, authors, journals, references, and keywords.

Results

A total of 2776 publications on analgesia and TKA were identified, with the United States having the highest number of publications. The University of Copenhagen was the most productive institution, and Kehlet, Henrik was the most prolific author. The Journal of Arthroplasty had the most publications and citations. The most common keywords were "TKA," "pain management," "postoperative pain," "Total hip arthroplasty (THA)," and "postoperative management." Keyword burst detection demonstrated that adductor canal block (ACB) was a recent research hotspot.

Conclusion

Our study revealed a sharp increase in global publications on analgesia and TKA, and this trend is expected to continue. Further research is necessary to determine the optimal regimen for multimodal analgesia, the ideal location and volume of ACB, and their clinical significance.

Assessment of the anti-inflammatory and analgesic effects of Opuntia ficus indica L. Cladodes extract

This study aimed to evaluate the anti-inflammatory and analgesic properties of the methanolic extract of Opuntia ficus indica L. in small animal (rats and mice model). The current treatment for febrile conditions often involves the use of non-steroidal anti-inflammatory drugs (NSAIDs), which can have adverse effects, particularly gastrointestinal ulcers. Therefore, there is a growing need to explore natural alternatives with fewer side effects. The study utilized various experimental models to assess the effects of the extract. The results demonstrated a significant analgesic effect of the extract, as evidenced by a reduction in pain induced by acetic acid and hot plate tests. Additionally, the extract exhibited anti-inflammatory effects, as indicated by a decrease in carrageenan-induced paw edema and dextran-induced inflammation. To gain insights into the chemical composition of the extract, HPLC analysis was conducted. The analysis successfully identified and quantified 20 compounds, including luteolin, galangin, catechin, thymol, methylated quercetin, quercetin, rutin, acacetin, hesperidin, apigenin, kaempferol, pinocembrin, chrysin, gallic acid, caffeic acid, ascorbic acid, ferulic acid, m-coumaric acid, rosmarinic acid, and trans-cinnamic acid.The findings suggest that Opuntia ficus indica L. extract holds promise as an effective and reasonably priced natural remedy for pain and inflammation in rats and mice model. The comprehensive chemical composition analysis provided valuable insights into the presence of various bioactive compounds, which may contribute to the observed therapeutic effects. Further research and exploration of the extract's mechanisms of action are warranted to fully understand its potential in small animal healthcare.

Exploring the Gender-Specific Impact of Intraperitoneal Bupivacaine on Early Postoperative Pain in Sleeve Gastrectomy

Background: Early postoperative pain is a significant problem in bariatric and metabolic surgery. Our study aimed to investigate the potential role of intraperitoneal bupivacaine hydrochloride in pain management in the early postoperative period after bariatric and metabolic surgery. Methods: This double-blind, prospective, randomized, controlled study included 68 individuals who underwent bariatric and metabolic surgery at the Department of Surgery, Istanbul Aydin University Hospital. The study group received 20 mL of 0.5% bupivacaine hydrochloride intraperitoneally at the operative site, and the control group received 20 mL of normal saline. Visual analog scale (VAS) scores of each patient were recorded at 2nd, 4th, and 6th hours postoperatively. Results: Our study found significant differences in VAS scores of patients between study group and control group at 2nd, 4th, and 6th hours postoperatively. Significant differences were found between male and female patients in the control group at 2nd, 4th, and 6th hours postoperatively. Interestingly, no significant difference was found between female patients in the study group and control group at 2nd, 4th, and 6th hours postoperatively. Conclusions: Our study suggests that intraperitoneal administration of bupivacaine hydrochloride is effective in reducing early postoperative pain in male patients. However, no significant difference was found between the study group and the control group in female patients. Our results indicate that there may be a gender-related difference in the response to bupivacaine administration. Further research is needed to confirm these findings and determine the optimal dosing and administration of local anesthetics for postoperative pain management.

Effects of subconjunctival ropivacaine, liposomal bupivacaine, and mepivacaine on corneal sensitivity in healthy horses

OBJECTIVE

To evaluate corneal sensitivity and adverse events following subconjunctival administration of three local anesthetics in horses.

STUDY DESIGN

Randomized, masked, crossover study.

ANIMALS

Twelve healthy adult mares.

METHODS

The subconjunctival space of the treated eye was injected with 0.2 mL of liposomal bupivacaine (1.3%), ropivacaine (0.5%), or mepivacaine (2%). All horses received each medication once and the contralateral eye received saline (control). Corneal touch threshold (CTT) was measured using a Cochet-Bonnet esthesiometer before sedation, after sedation, and at specified intervals until it returned to baseline. Ocular examinations were performed at 24-, 72, and 168 h post-injection to monitor for adverse effects.

RESULTS

The mean total time of anesthesia (TTA) was 168.3 min for ropivacaine, 169.2 min for liposomal bupivacaine, 103.3 min for mepivacaine and 30.7 min for the control. TTA for liposomal bupivacaine (p < .001) and ropivacaine (p = .001) was longer than the control. TTA for mepivacaine was not different from the control (p = .138), liposomal bupivacaine (p = .075) or ropivacaine (p = .150). Injection site hemorrhage reduced TTA regardless of treatments (p = .047). No adverse effects attributed to injections were noted.

CONCLUSION

All three medications were well tolerated. Subconjunctival administration of ropivacaine and liposomal bupivacaine resulted in longer TTAs compared to the control; however, their TTAs were not different from that of mepivacaine.

CLINICAL SIGNIFICANCE

Subconjunctivally administered liposomal bupivacaine and ropivacaine are viable options to provide prolonged corneal analgesia in horses. Future studies are needed to assess the efficacy in diseased eyes.

Incisional infiltration versus transversus abdominis plane block of liposomal bupivacaine after midline vertical laparotomy for suspected gynecologic malignancy: a pilot study

Background

To evaluate whether incisional infiltration of liposomal bupivacaine would decrease opioid requirement and pain scores after midline vertical laparotomy for suspected or known gynecologic malignancy compared with transversus abdominis plane (TAP) block with liposomal bupivacaine.

Methods

A prospective, single blind randomized controlled trial compared incisional infiltration of liposomal bupivacaine plus 0.5% bupivacaine versus TAP block with liposomal bupivacaine plus 0.5% bupivacaine. In the incisional infiltration group, patients received 266 mg free base liposomal bupivacaine with 150 mg bupivacaine hydrochloride. In the TAP block group, 266 mg free base bupivacaine with 150 mg bupivacaine hydrochloride was administered bilaterally. The primary outcome was total opioid use during the first 48-hour postoperative period. Secondary outcomes included pain scores at rest and with exertion at 2, 6, 12, 24 and 48 h after surgery.

Results

Forty three patients were evaluated. After interim analysis, a three-fold higher sample size than originally calculated was required to detect a statistically significant difference. There was no clinical difference between the two arms in mean opioid requirement (morphine milligram equivalents) for the first 48 h after surgery (59.9 vs. 80.8, p = 0.13). There were no differences in pain scores at rest or with exertion between the two groups at pre-specified time intervals.

Conclusion

In this pilot study, incisional infiltration of liposomal bupivacaine and TAP block with liposomal bupivacaine demonstrated clinically similar opioid requirement after gynecologic laparotomy for suspected or known gynecologic cancer. Given the underpowered study, these findings cannot support the superiority of either modality after open gynecologic surgery.

Liposomal bupivacaine nerve block provides better pain control post-total shoulder arthroplasty than continuous indwelling catheter

BACKGROUND

Pain control is essential to successful total shoulder arthroplasty (TSA).

MATERIALS AND METHODS

This non-blinded, randomized clinical trial compared shoulder pain, narcotic use, interscalene (IS) block application time, and costs in 76 subjects who were randomly assigned to receive either a single injection IS nerve block of 10 cc (133 mg) liposomal bupivacaine mixed with 10 cc of 0.5% bupivacaine (Group 1), or 20 cc of 0.5% ropivacaine direct injection combined with an indwelling IS nerve block catheter delivering 0.2% ropivacaine at a continual 4 cc/h infusion for the initial 3 post-operative days (Group 2). Surgical time, local anesthesia duration, hospital stay length, morphine milligram equivalents (MME) consumed, worst shoulder pain at 24, 48 and 72 h, and complications were recorded. Patient reported function, pain and activity level surveys were completed before, and 6-week post-TSA (P < 0.05).

RESULTS

Group 1 had less pain 24-h (0.72 ± 0.8 vs. 3.4 ± 2.9, p < 0.0001) and 48-h (2.5 ± 2.2 vs. 4.8 ± 2.6, p = 0.005) post-TSA. At 24-h post-TSA, MME consumption was similar (Group 1 = 4.5 ± 6.4 vs. Group 2 = 3.7 ± 3.8, p = 0.54), but was lower for Group 1 at 48 h (0.0 ± 0.0 vs. 0.64 ± 0.99, p = 0.001). Group 2 had longer IS block application time (10.00 ± 4.6 min vs. 4.84 ± 2.7 min, p < 0.0001). Only group 2 had a strong relationship between MME consumption over the first 24-h post-TSA and pain 24-h post-TSA (r = 0.76, p < 0.0001), a moderate relationship with pain 48-h post-TSA (r = 0.59, P = 0.001), and a weak relationship with pain 72-h post-TSA (r = 0.44, P = 0.02). Significant relationships for these variables were not observed for Group 1 (r ≤ 0.30, p ≥ 0.23). Group 1 IS block costs were less/patient than Group 2 ($190.17 vs. $357.12 USD).

CONCLUSION

A single shot, liposomal bupivacaine interscalene nerve block provided better post-TSA pain control with less narcotic consumption, less time for administration and less healthcare system cost compared to interscalene nerve block using a continuous indwelling catheter.

LEVEL OF EVIDENCE

Level I, Prospective, Randomized.

Development of Squalene-Based Oil-in-Water Emulsion Adjuvants Using a Self-Emulsifying Drug Delivery System for Enhanced Antigen-Specific Antibody Titers

INTRODUCTION

A recombinant protein cannot induce sufficient immune response by itself. Various substances, including cytokine and mineral, have been used as adjuvants to enhance the immunogenicity and efficacy of vaccines; however, most of them induce excessive immune responses or exhibit cytotoxicity. In this study, a self-emulsifying drug delivery system (SEDDS), an isotropic mixture of oil, surfactant, and solvent, was designed for oil-in-water emulsions as a non-toxic adjuvant to increase immune response to antigens.

METHODS

Squalene-based oil-in-water emulsions were prepared by SEDDS to assess its value as an adjuvant. Fifteen emulsions (F1-F15) were prepared by stirring two types of surfactants (Span® 85 and Kolliphor® RH40), and squalene and carboxymethyl cellulose (CMC) were added at different ratios. The physical properties and viscosity of the 15 emulsions were evaluated by measuring droplet size, zeta potential, and polydispersity index. The toxic effect of emulsions was assessed by acute toxicity test in mice. Mice were immunized twice with 1:1 mixtures of antigen and adjuvant (15 emulsions, phosphate-buffered saline, and commercial alum-based adjuvant). Antigen-specific antibody titers from immunized mice serum were measured by an indirect enzyme-linked immunosorbent assay.

RESULTS

All emulsions exhibited droplet sizes ranging from 322 to 812 nm and maintained zeta potential values between -30 mV to -10 mV for 4 weeks, indicating good physical stability as a vaccine adjuvant. Additionally, all emulsions were non-toxic, and they induced humoral immunity at a similar level compared to commercial alum-based adjuvant in the first immunization. However, 12% squalene-based oil-in-water emulsion containing 0.5% of ultra-high viscosity CMC (F15) showed significantly higher immune response than a commercial adjuvant in the second immunization.

CONCLUSION

Squalene-based oil-in-water emulsions could be conveniently prepared using SEDDS technique and are non-toxic and stable at room temperature storage. Moreover, squalene-based oil-in-water emulsions show enhanced immune induction with antigen; hence, they can possibly be used as effective adjuvants.

Liposomal bupivacaine does not decrease postoperative opioid use or length of hospital stay in patients undergoing anterior cervical discectomy and fusion

BACKGROUND

Despite its widespread use, definitive data demonstrating the efficacy of liposomal bupivacaine (LB) is limited especially in patients undergoing anterior cervical discectomy and fusion (ACDF). Therefore, this investigation examined whether ACDF patients who received intra-operative LB (LB cohort) exhibited decreased post-operative opioid use and lengths of hospital stay (LOS) compared to ACDF patients who did not receive intra-operative LB (controls).

METHODS

Eighty-two patients who underwent primary ACDF by a single surgeon from 2016 to 2019 were identified from an institutional database. Fifty-nine patients received intra-operative LB while twenty-three did not. Patient characteristics, medical comorbidities, complications, post-operative opioid consumption, and LOS data were collected.

RESULTS

The LB cohort did not require fewer opioids on post-operative day (POD) 0, POD1, POD2, or throughout the hospital course after normalizing by LOS (total per LOS). The number of cervical vertebrae involved in surgery, but not LB use, predicted opioid consumption on POD0, POD1, and total per LOS. For every vertebral level involved, 242 additional morphine milligram equivalents (MME) were consumed on POD0, 266 additional MME were utilized on POD1, and 130 additional MME were consumed in total per LOS.

CONCLUSIONS

ACDF patients who received intra-operative LB did not require fewer post-operative opioids or exhibit a decreased LOS compared to controls. Patients whose procedures involved a greater number of cervical vertebrae were associated with greater opioid consumption on POD0, POD1, and total per LOS. ACDF patients, especially those who had a high number of vertebrae involved, may require alternative analgesia to LB.

Novel temperature-responsive hydrogel injected to the incision site for postoperative pain relief in laparoscopic abdominal surgery: a single-blind, randomized, pivotal clinical trial

BACKGROUND

A temperature-responsive hydrogel (PF-72; TGel Bio, Inc., Ltd, Seoul, Korea), developed as a sustained drug delivery device, can be mixed with ropivacaine to reduce pain in the incision area. The hydrogel is soluble at low temperatures (2-8 °C) and is converted into a gel at high temperatures (> 30 °C). We aimed to evaluate whether the administration of ropivacaine using PF-72 at incision sites reduces pain until 72 h postoperatively in patients undergoing laparoscopic stomach or colorectal surgery.

METHODS

Patients were randomly assigned to the control group (0.75% ropivacaine) or PF-72 group (PF-72 mixed with 0.75% ropivacaine). Before surgical incision closure, 0.75% ropivacaine or PF-72 mixed with 0.75% ropivacaine was injected into the subcutaneous fat and muscle of all incisions. Postoperative pain was evaluated by the Numerical Rating Scale (NRS, 0 = no pain, 10 = most severe pain) for wound pain at 3, 6, 24, 48, and 72 h after the end of surgery.

RESULTS

Ninety-nine patients (control, n = 51; PF-72, n = 48) were included in the analysis. The areas under the curve of NRS for wound pain until 72 h in the control group and the PF-72 group were 188.7 ± 46.1 and 135.3 ± 49.9 h, respectively (P < 0.001). The frequency of the administration of rescue analgesics in the general ward was similar between the two groups.

CONCLUSION

PF-72 mixed with 0.75% ropivacaine reduced postoperative pain until 72 h in patients undergoing laparoscopic surgery. Although the study population was not large enough for safety evaluation, no adverse events associated with PF-72 were observed.

[Liposomal bupivacaine-No breakthrough in postoperative pain management]

One of the main limitations concerning the use of local anesthetics is due to their restricted duration of action. In recent years, liposomal formulations with prolonged release kinetics have been developed to extend the pharmacological duration of action of the 1‑stage peripheral regional anesthesia (single-shot procedure) and thus bring about a longer duration of action. The focus here is particularly on achieving postoperative freedom from pain for at least 24 h (or even better 48 h) and thus early mobilization of patients using on-demand medication causing (at most) minor local sensory blockade without causing motor impairments (at least that is the ideal). Therefore, methods of utilizing slow-release drugs as seen in liposomal carrier systems have experienced increasing scientific attention in the last few years. A common modern pharmacological example with a theoretically significantly longer duration of action is liposomal bupivacaine, an amide local anesthetic. Due to a multivesicular liposome structure, the retarded release of the active component bupivacaine HCl leads to a theoretical pharmacological effectiveness of up to 72 h. Previous studies consistently showed a safety profile comparable to conventional bupivacaine HCl. Liposomal bupivacaine has been approved by the U.S. Food and Drug Administration (FDA) under the trade name Exparel© (Pacira Pharmaceuticals, Parsippany, NJ, USA) since 2011; however, its use is currently limited to local wound infiltration, transverse abdominis plane (TAP) blocks, and interscalene nerve blocks of the brachial plexus. In 2020, the European Medicines Agency (EMA) also approved the use of liposomal bupivacaine for blockade of the brachial plexus or the femoral nerve and as a field block or for wound infiltration to treat postoperative pain. So far, studies on the clinical effectiveness of liposomal bupivacaine have been very heterogeneous and there have been no conclusive meta-analyses with sufficient rigor or significance. Recent systematic reviews and meta-analyses, combining the results of clinical studies regarding the analgesic efficiency of liposomal bupivacaine in different fields of application, consistently refuted any benefit of clinical relevance provided by the liposomal formulation. There is currently sufficient evidence to now end the ongoing debate around liposomal bupivacaine. The aim of this work is to give the reader a current, evidence-based overview of this substance.

Comparison of in vitro and in vivo Toxicity of Bupivacaine in Musculoskeletal Applications

The recent societal debate on opioid use in treating postoperative pain has sparked the development of long-acting, opioid-free analgesic alternatives, often using the amino-amide local anesthetic bupivacaine as active pharmaceutical ingredient. A potential application is musculoskeletal surgeries, as these interventions rank amongst the most painful overall. Current literature showed that bupivacaine induced dose-dependent myo-, chondro-, and neurotoxicity, as well as delayed osteogenesis and disturbed wound healing in vitro. These observations did not translate to animal and clinical research, where toxic phenomena were seldom reported. An exception was bupivacaine-induced chondrotoxicity, which can mainly occur during continuous joint infusion. To decrease opioid consumption and provide sustained pain relief following musculoskeletal surgery, new strategies incorporating high concentrations of bupivacaine in drug delivery carriers are currently being developed. Local toxicity of these high concentrations is an area of further research. This review appraises relevant in vitro, animal and clinical studies on musculoskeletal local toxicity of bupivacaine.

Opioid Sparing at 24 h after Total Shoulder Arthroplasty by Undiluted Liposomal Bupivacaine Single Shot Interscalene Block: A Randomized Clinical Trial, First Results

Background: The purpose of this study was to compare postoperative opioid consumption following total shoulder arthroplasty, after: (A) a single-shot undiluted liposomal bupivacaine (LB; commercial name: Exparel) interscalene block, or (B) a Ropivacaine block (R), supplemented with continuous catheter infusion. Methods: This prospective, randomized study (NCT03739021) compared postoperative analgesic requirements in Morphine Milligram Equivalent (MME) during the first 24 h after discharge from the post-anesthesia care unit (PACU) in patients receiving total shoulder arthroplasty. Two similar groups of 30 patients each received equivalent general operative anesthesia. Preoperative interscalene block was performed with either 10mL of undiluted liposomal bupivacaine (LB) or ropivacaine (R) 0.5% plus continuous catheter infusion. Results: There were no differences between the two groups regarding age, gender, length of surgery, intraoperative narcotic usage, or length of hospital stay. The time required to administer (LB) compared to (R) was significantly reduced (5 min vs. 15 min). The LB group experienced a reduction in MME during the first 24 h after PACU discharge (25 vs. 41 MME). Conclusion: A single shot of undiluted liposomal bupivacaine (LB) provided a significant (p = 0.045) reduction in opioid use during the first 24 h after shoulder replacement surgery compared to ropivacaine (R) with continuous catheter infusion. A larger sample group will be required to bolster these results. There was no measured difference in reported pain level. LB also took less time to administer.

Impact of Liposomal Bupivacaine on Post-Operative Pain and Opioid Usage in Thyroidectomy

OBJECTIVES

Opioid analgesia has been integral in post-operative pain control for decades. The over-prescription of opioids, commonly in the surgical patient, has contributed to the current opioid epidemic. Liposomal bupivacaine (LB), a long-acting analgesia formulation, has demonstrated decreased post-operative pain and opioid requirements in patients treated across multiple surgical subspecialties. The aims of this retrospective study are to assess post-operative pain and opioid use in patients who received LB at the time of thyroidectomy.

METHODS

A cohort-matched retrospective review of patients who underwent thyroidectomy by 2 surgeons between January 2010 and December 2019 was performed. Patients were divided into those that received LB intraoperatively and those that did not. Statistical analyses were performed using the Chi-square or Fisher's exact test, and 2-sample T-test or Wilcoxon rank sum test.

RESULTS

Of the 201 patients included in this study, 113 patients received LB and 88 did not. Patients who received LB had a lower median visual analog scale (VAS) pain score (2 vs 3, P = .2252), lower maximum VAS pain score (6 vs 7, P = .0898), were less likely to require opioid medications (73.5% vs 85.2%, P = .0434), and had a lower percentage of daily morphine milligram equivalent value ≥45 (89.8% vs 95.3%, P = .1581) during the post-operative period when compared to those that did not.

CONCLUSION

This study suggests a role for incisional infiltration with LB for post-operative pain management in patients undergoing transcervical thyroidectomy. We report reduced post-operative pain scores and opioid analgesia requirements in patients who received LB.

Efficacy of Liposomal Bupivacaine for Sternotomy Pain After Cardiac Surgery: A Retrospective Analysis

BACKGROUND

Multimodal analgesia is a cornerstone of postoperative pain management. Different formulations of local anesthetics are available. Data to support these treatment options are limited.

OBJECTIVE

To determine the efficacy of liposomal bupivacaine compared with bupivacaine or ropivacaine in patients undergoing sternotomy for coronary artery bypass graft (CABG) and/or valve surgery.

METHODS

Single-center, retrospective, observational study at a community teaching hospital. Patients included were 18 years of age or older undergoing CABG and/or valve surgery via median sternotomy and received either liposomal bupivacaine or an active comparator. The primary outcome was opioid utilization in morphine milligram equivalent (MME) from 0 to 72 hours.

RESULTS

A total of 376 patients were included, 223 in the liposomal bupivacaine arm and 153 in the active comparator arm. There was no difference in the MME use from 0 to 72 hours among patients in the liposomal bupivacaine group compared with the comparator group (114.2 mg [75.55] vs 107.6 mg [68.4], P = 0.38). After Bonferroni correction, there was no difference in pain scores at individual time points. At 24- and 48-hour post-op, pain scores were higher with liposomal bupivacaine at 4.4 (2.7) vs 3.5 (2.8) (P = 0.01) and 3.1 (2.9) vs 2.4 (2.6) (P = 0.02).

CONCLUSION AND RELEVANCE

Based on these findings and previous studies, liposomal bupivacaine should not be routinely used for CABG and/or valve surgery through a median sternotomy given lack of superiority. This helps inform surgical practice to the role of anesthetics as part of the multimodal analgesia regimen.

Updates on Wound Infiltration Use for Postoperative Pain Management: A Narrative Review

Local anesthetic wound infiltration (WI) provides anesthesia for minor surgical procedures and improves postoperative analgesia as part of multimodal analgesia after general or regional anesthesia. Although pre-incisional block is preferable, in practice WI is usually done at the end of surgery. WI performed as a continuous modality reduces analgesics, prolongs the duration of analgesia, and enhances the patient’s mobilization in some cases. WI benefits are documented in open abdominal surgeries (Caesarean section, colorectal surgery, abdominal hysterectomy, herniorrhaphy), laparoscopic cholecystectomy, oncological breast surgeries, laminectomy, hallux valgus surgery, and radical prostatectomy. Surgical site infiltration requires knowledge of anatomy and the pain origin for a procedure, systematic extensive infiltration of local anesthetic in various tissue planes under direct visualization before wound closure or subcutaneously along the incision. Because the incidence of local anesthetic systemic toxicity is 11% after subcutaneous WI, appropriate local anesthetic dosing is crucial. The risk of wound infection is related to the infection incidence after each particular surgery. For WI to fully meet patient and physician expectations, mastery of the technique, patient education, appropriate local anesthetic dosing and management of the surgical wound with “aseptic, non-touch” technique are needed.

Reduced Opioid Use Among Patients Who Received Liposomal Bupivacaine for ACL Reconstruction

Standard multimodal pain management for anterior cruciate ligament reconstruction typically includes a combination of local anesthetics, nonsteroidal anti-inflammatory drugs, and opioids. Opioids present a substantial risk, and there is a rising number of prescription opioid-related overdoses in the United States. The goal of this study was to evaluate the quantity of opioids prescribed to patients who received liposomal bupivacaine as a component of their multi-modal pain regimen. The electronic medical records of patients who underwent anterior cruciate ligament reconstruction by a single surgeon at an urban hospital during a 2-year period were evaluated. Patients in the case group received liposomal bupivacaine and those in the control group did not. Statistical analysis of the number of pills prescribed and numeric pain rating scale scores was performed with a 2-tailed unequal variance t test. Statistical analysis of opioid prescription refills was performed with a chi-square test. A total of 67 patients were included. The mean number of 5-mg oxycodone tablets prescribed to the case group (9.29±10.29 tablets) was significantly lower (P<.01) compared with the number prescribed to the control group (66.26±37.13 tablets). Patients in the case group also were less likely to require an opioid prescription refill at the first follow-up appointment (P<.01; absolute risk reduction, 50%; number needed to treat, 2). Mean numeric pain rating scale score at 2 weeks was 2.8±2.1 in the case group and 3.8±2.4 in the control group (P=.09). Patients who received liposomal bupivacaine as part of multimodal pain management had significantly fewer opioid prescriptions. Despite the reduction in opioids prescribed, patients in the case group only showed a trend toward a reduction in pain at 2-week follow-up. [Orthopedics. 2021;44(2):e229-e235.].

Intrathecal nalbuphine vs. buprenorphine as an adjuvant in lower limb orthopedic surgeries: a prospective randomized controlled study

This study aimed to compare the efficacy of intrathecal nalbuphine and buprenorphine as an adjuvant to heavy bupivacaine (0.5%) for spinal anesthesia in lower limb orthopedic surgeries to improve the quality of spinal anesthesia (onset, duration, and side effects) and prolongation of postoperative analgesia. Sixty patients were recruited into this single-centered, double-blinded, hospital-based, prospective, comparative study conducted in 2017–2018. They were randomly and equally (n = 30) allocated into two groups: nalbuphine group which received 0.5 mL (0.8 mg) of nalbuphine with 3 mL of heavy (0.5%) hyperbaric bupivacaine and buprenorphine group which received 0.5 mL (60 mg) of buprenorphine with 3 mL of heavy hyperbaric bupivacaine. Intraoperatively, onset and duration of blockade (motor and sensory), and time for first dose of rescue analgesia were recorded in both groups at regular intervals. Heart rate, blood pressure, Visual Analogue Scale score and side effects were also recorded postoperatively for 12 hours. The demographic parameters, time of onset of sensory block and motor block, and duration of motor block were comparable between nalbuphine and buprenorphine groups. The duration of sensory block in the buprenorphine group was longer than in the nalbuphine group. Time to the first dose of rescue analgesia was delayed in buprenorphine group as compared to nalbuphine group. In both groups maximum patients achieved maximum height of sensory block at 90 minutes. There were significant differences in the mean heart rate and blood pressure between buprenorphine and nalbuphine groups. Nalbuphine group patients achieved a Visual Analogue Scale score > 4 earlier as compared to buprenorphine group. Few side effects were observed in both groups. Intrathecal buprenorphine is a better adjuvant to 0.5% bupivacaine in the spinal anesthesia for lower limb orthopedic surgeries, as it provides longer sensory block and delayed administration of first dose of rescue analgesia with negligible side-effects. The study was approved by Institutional Ethics Committee of Krishna Institute of Medical Sciences (approval number: KIMSDU/IEC/03/2017) on November 23, 2017.

Improvement of Butamben Anesthetic Efficacy by the Development of Deformable Liposomes Bearing the Drug as Cyclodextrin Complex

This work was aimed at enhancing butamben (BTB) anesthetic efficacy by the "drug-in cyclodextrin (CD)-in deformable liposomes" strategy. In the study, phase-solubility studies with natural (α-, β-, γ-) and derivative (hydroxypropyl-α-and β-, sulfobutylether-β, methyl-β) CDs evidenced the highest BTB affinity for βCD and its derivatives and indicated methyl-βCD (RAMEB) as the best carrier. Drug-RAMEB complexes were prepared by different techniques and were characterized for solid-state and dissolution properties. The best BTB-RAMEB product was chosen for entrapment in the aqueous core of deformable liposomes containing stearylamine, either alone or with sodium cholate, as edge activators. Double-loaded (DL) liposomes, bearing the lipophilic drug (0.5% w/v) in the bilayer and its hydrophilic RAMEB complex (0.5% w/v) in the aqueous core, were compared to single-loaded (SL) liposomes bearing 1% w/v plain drug in the bilayer. All vesicles showed homogeneous dimensions (i.e., below 300 nm), high deformability, and excellent entrapment efficiency. DL-liposomes were more effective than SL ones in limiting drug leakage (<5% vs. >10% after a 3 months storage at 4 °C). In vivo experiments in rabbits proved that all liposomal formulations significantly (p < 0.05) increased the intensity and duration of drug anesthetic action compared to its hydroalcoholic solution; however, DL liposomes were significantly (p < 0.05) more effective than SL ones in prolonging BTB anesthetic effect, owing to the presence of the drug-RAMEB complex in the vesicle core, acting as a reservoir. DL liposomes containing both edge activators were found to have the best performance.

Osmotically balanced, large unilamellar liposomes that enable sustained bupivacaine release for prolonged pain relief in in vivo rat models

To efficiently prolong analgesic effects, we developed osmotically balanced, large unilamellar liposomes (~ 6 μm in diameter) in which highly concentrated bupivacaine (up to 30 mg/mL) was encapsulated, and their sustained bupivacaine release was highly effective in relieving postoperative pain over 24 h in a rat model. Our reverse-phase evaporation method based on non-toxic alcohol, ethanol, enabled simple and cost-effective production of bupivacaine-loaded liposomes, of which osmotic pressure was readily balanced to improve the structural stability of the enlarged unilamellar liposomes along with extension of their shelf life (> a month). The in vitro release profile verified that the release duration of the bupivacaine-loaded liposomes extended up to 6 days. For the in vivo study, male Sprague–Dawley rats were used for the incisional pain model, simulating postoperative pain, and the mechanical withdrawal threshold (MWT) was measured using a von Frey filament. Compared to the control group that received intraplantar administration of normal saline, the group of liposomal bupivacaine showed that the initially increased MWT gradually decreased up to 24 h, and importantly, the analgesic effect of the liposomal bupivacaine was maintained 6 times longer than that of bupivacaine only, proving the potential of effective long-acting anesthetics.

Degradable polymeric vehicles for postoperative pain management

Effective control of pain management has the potential to significantly decrease the need for prescription opioids following a surgical procedure. While extended release products for pain management are available commercially, the implementation of a device that safely and reliably provides extended analgesia and is sufficiently flexible to facilitate a diverse array of release profiles would serve to advance patient comfort, quality of care and compliance following surgical procedures. Herein, we review current polymeric systems that could be utilized in new, controlled post-operative pain management devices and highlight where opportunities for improvement exist.

Regional anesthesiological support for the implementation of surgical interventions in the abdomen of dogs

Widespread use of surgical interventions in the abdomen of dogs determines the relevance of the study. The research tested the influence of therapeutic epidural blockade with 0.2% bupivacaine after surgical interventions on the background of potentiated local anaesthesia on the body of clinically healthy dogs undergoing ovariohysterectomy. In the control group postoperative analgesia was performed with the nonsteroidal anti-inflammatory drug rimadyl on the background of potentiated thiopental anaesthesia. Wound healing rates were determined in 10 animals of both control and experimental groups; blood counts and the level of inflammatory response were indicated in 5 animals of each group. The dynamics of reparative processes and complete wound healing in dogs of the experimental group occurred earlier than in animals of the control group, which confirmed the fact that the use of bupivacaine had a beneficial effect on tissue regeneration. The results of morphological and biochemical parameters of blood in animals of the experimental group manifested only an increase of leukocytes by 1.58 times, fibrinogen by 2.02 times, while in dogs of the control group the level of erythrocytes, haemoglobin and hematocrit decreased, leukocytes increased by 1.74 times, platelets decreased by 2.87 times and fibrinogen increased by 1.72 times. Among the stress response markers in the control group there was a 1.94 times increase in glucose level after surgery. In the experimental group there was a decrease in the intensity of the inflammatory reaction in dogs, accompanied by an increase of anti-inflammatory interleukin 4 (IL-4) only on the seventh day – 1.86 times, while in the control group the level of anti-inflammatory interleukin 1 receptor antagonist (IL-1RA) after three days increased by 2.30 times, after seven days – by 2.48 times, and the level of proinflammatory interleukin 6 (IL-6) after surgery increased by 2.57 times. It will be promising to conduct further research on the influence of therapeutic blockades with bupivacaine in animals in cases of various surgical interventions and pathological conditions, which will lead to faster recovery of animals and alleviate pathological processes.

Interventional Treatment for Stroke Prevention

Closure of the left atrial appendage using percutaneous transcatheter occlusion devices is used for stroke prevention as an alternative for patients with a high risk or contraindications for long-term oral anticoagulation use. Herein, we will discuss the practical aspects of five among the available devices used for interventional left atrial appendage occlusion: Watchman, Amulet, WaveCrest, LAmbre, and Lariat.

Timing of Transversus Abdominis Plane Block and Postoperative Pain Management

Background

Transversus abdominis plane (TAP) blocks using liposomal bupivacaine can reduce postoperative pain and opioid consumption after surgery. The impact of timing of administration of such blocks has not been determined.

Materials and Methods

A retrospective cohort study of all adult patients that underwent colorectal procedures between January 2013 and October 2015 and received TAP blocks with liposomal bupivacaine at our institution was conducted. The primary outcomes were postoperative pain scores and opioid consumption. Secondary outcomes included postoperative use of non-opioid analgesics as well as total hospital cost of admission and postoperative hospital length of stay.

Results

A total of 287 patients were identified and included in the analysis. A total of 71 patients received blocks prior to induction of general anesthesia (pre-ind), 85 patients received blocks after induction of general anesthesia but prior to surgical incision (post-ind) and 131 patients received blocks after completion of surgery (post-op). No significant differences were observed in the postoperative pain scores (either in the first 4 hours or for the entire duration of hospital stay) or opioid consumption between the pre-ind and the post-ind groups. More ketorolac was used in the post-op group compared to the pre-ind group (or= 3.36, 95% CI (1.08, 10.43); p=0.03).

Conclusion

Our findings suggest that there seems to be no difference if tap blocks with liposomal bupivacaine are performed before or after induction of anesthesia. Patient preference as well as operating room efficiency should be considered when deciding on the timing of these blocks.

Liposomes for Intra-Articular Analgesic Drug Delivery in Orthopedics: State-of-Art and Future Perspectives. Insights from a Systematic Mini-Review of the Literature

Background and objectives: Liposomal structures are artificial vesicles composed of one or several lamellae of phospholipids which surround an inner aqueous core. Given the amphoteric nature of phospholipids, liposomes are promising systems for drug delivery. The present review provides an updated synthesis of the main techniques for the production of liposomes for orthopedic applications, focusing on the drawbacks of the conventional methods and on the advantages of high pressure techniques. Materials and Methods: Articles published in any language were systematically retrieved from two major electronic scholarly databases (PubMed/MEDLINE and Scopus) up to March 2020. Nine articles were retained based on the “Preferred Reporting Items for Systematic Reviews and Meta-Analyses” (PRISMA) guidelines. Results: Liposome vesicles decrease the rate of inflammatory reactions after local injections, and significantly enhance the clinical effectiveness of anti-inflammatory agents providing controlled drug release, reducing toxic side effects. Conclusions: This review presents an update on the improvement in musculoskeletal ailments using liposome treatment.

Chondrotoxicity of Local Anesthetics: Liposomal Bupivacaine Is Less Chondrotoxic than Standard Bupivacaine

Objective

The purpose of this study is to determine whether (1) liposomal bupivacaine is chondrotoxic; (2) the chondrotoxicity of liposomal bupivacaine differs from standard bupivacaine; and (3) chondrotoxic effects are time dependent.

Materials and Methods

We obtained 72 10 mm articular cartilage plugs from 12 fresh bovine distal femoral knee joints and exposed them to either saline, 0.5% bupivacaine, or liposomal bupivacaine for either 30 or 90 minutes. Twenty-four hours after treatment, chondrocyte viability was measured with the use of a fluorescent live/dead assay. An ANOVA test of variance was performed followed by a Holm-Sidak test to make pairwise comparisons across conditions. Student's t-test was used to compare means.

Results

Percent viability of cells exposed to liposomal bupivacaine for 30 minutes was less versus saline control (53.9% ± 21.5% vs. 73.7 ± 18.4%, p=0.035), and this remained significant at 90 minutes (49.1% ± 20.3% vs. 67.2% ± 25.6%, p < 0.001). Liposomal bupivacaine had less chondrotoxic effects when compared with bupivacaine after 90 minutes, with greater viability (49.1% ± 20.3% vs. 21.4% ± 14.0%, p=0.003). Chondrotoxicity was found to be time dependent within the bupivacaine group (percent viability at 30 min: 45.5 ± 18.2%, 90 min: 21.4 ± 14.0%, p=0.001); however, liposomal bupivacaine did not demonstrate a significant time-dependent chondrotoxic relationship (p=0.583).

Conclusions

Bupivacaine and liposomal bupivacaine are both toxic to chondrocytes. Liposomal bupivacaine is less chondrotoxic than standard bupivacaine and does not demonstrate a time-dependent toxicity.

Efficacy of transversus abdominis plane (TAP) block in colorectal surgery: a systematic review and meta-analysis

BACKGROUND

Multimodal opioid-sparing analgesia is a key component of the enhanced recovery after surgery (ERAS) protocol for postoperative pain management. Transversus abdominis plane (TAP) block has contributed to the implementation of this approach in different kinds of surgical procedures. The aim of this study was to evaluate the efficacy of TAP block and its impact on recovery in colorectal surgery.

METHODS

A comprehensive literature search of the PubMed, Embase, and Scopus databases was conducted. Studies that compared TAP block to a control group (no TAP block or placebo) after colorectal resections were included. The effects of TAP block in patients undergoing colorectal surgery were assessed, including the technical aspects of the procedure. Two measures were used to evaluate the effectiveness of postoperative pain control: a numeric pain rating score at rest and on coughing or movement at 24 h following surgery and the opioid requirement at 24 h. Clinical aspects of recovery were postoperative ileus, surgical site infection, postoperative nausea and vomiting, and length of hospital stay.

RESULTS

Sixteen studies were included in the analysis. Data showed that TAP block is a safe procedure associated with a significant reduction in the pain score at rest [WMD - 0.91 (95% CI - 1.56; - 0.27); p < 0.05] and on coughing or movement [WMD - 0.36 (95% CI - 0.72; - 0.01); p < 0.05] at 24 h after surgery and a significant decrease in morphine consumption in the TAP block group the day after surgery [WMD - 2.07 (95% CI - 2.63; - 1.51); p < 0.001].

CONCLUSIONS

TAP block appears to provide both an effective analgesia and a significant reduction in opioid use on the first postoperative day after colorectal surgery. Its use does not seem to lead to increased postoperative complications.

Intrathecal drug delivery in the era of nanomedicine

Administration of substances directly into the cerebrospinal fluid (CSF) that surrounds the brain and spinal cord is one approach that can circumvent the blood-brain barrier to enable drug delivery to the central nervous system (CNS). However, molecules that have been administered by intrathecal injection, which includes intraventricular, intracisternal, or lumbar locations, encounter new barriers within the subarachnoid space. These barriers include relatively high rates of turnover as CSF clears and potentially inadequate delivery to tissue or cellular targets. Nanomedicine could offer a solution. In contrast to the fate of freely administered drugs, nanomedicine systems can navigate the subarachnoid space to sustain delivery of therapeutic molecules, genes, and imaging agents within the CNS. Some evidence suggests that certain nanomedicine agents can reach the parenchyma following intrathecal administration. Here, we will address the preclinical and clinical use of intrathecal nanomedicine, including nanoparticles, microparticles, dendrimers, micelles, liposomes, polyplexes, and other colloidalal materials that function to alter the distribution of molecules in tissue. Our review forms a foundational understanding of drug delivery to the CSF that can be built upon to better engineer nanomedicine for intrathecal treatment of disease.

Effect of bupivacaine on postoperative pain and analgesics use after single-incision laparoscopic appendectomy: double-blind randomized study

Purpose

Local anesthetics can decrease postoperative pain after appendectomy. This study sought to verify the efficacy of bupivacaine on postoperative pain and analgesics use after single-incision laparoscopic appendectomy (SILA).

Methods

Between March 2014 and October 2015, 68 patients with appendicitis agreed to participate in this study. After general anesthesia, patients were randomized to bupivacaine or control (normal saline) groups. The assigned drugs were infiltrated into subcutaneous tissue and deep into anterior rectus fascia. Postoperative analgesics use and pain scores were recorded using visual analogue scale (VAS) by investigators at 1, 8, and 24 hours and on day 7. All surgeons, investigators and patients were blinded to group allocation.

Results

Thirty patients were allocated into the control group and 37 patients into bupivacaine group (one patient withdrew consent before starting anesthesia). Seven from the control group and 4 from the bupivacaine group were excluded. Thus, 23 patients in the control group and 33 in the bupivacaine group completed the study. Preoperative demographics and operative findings were similar. Postoperative pain and analgesics use were not different between the 2 groups. Subgroup analysis determined that VAS pain score at 24 hours was significantly lower in the bupivacaine group (2.1) than in the control group (3.8, P = 0.007) when surgery exceeded 40 minutes. During immediate postoperative period, bupivacaine group needed less opioids (9.1 mg) than control (10.4 mg).

Conclusion

Bupivacaine did not decrease pain and analgesics use. When surgery exceeded 40 minutes, bupivacaine use might be associated with less pain and less analgesics use.

The Role of Exparel Plus Meloxicam for Postoperative Pain Management

PURPOSE OF REVIEW

Acute postoperative pain reduction is a major target against the opioid crisis. While opioids have traditionally been the mainstay for postoperative analgesia, current practice has focused on a multimodal approach to pain control, including ultrasound-guided blocks with longer acting local anesthetic agents.

RECENT FINDINGS

Non-steroidal anti-inflammatory drugs (NSAIDs), such as meloxicam, are an important class of medications utilized to manage pain in the perioperative period. An additional treatment used in perioperative or postoperative pain relief is Exparel, a bupivacaine (sodium channel blocker) liposomal injectable suspension with a 3-4-day duration of action. The long-acting mechanism and formulation of Exparel consistently has demonstrated decreased opioid use and pain scores in patients undergoing many different surgical procedures. A concern is that pH negatively alters the efficacy of bupivacaine, as in cases of inflamed tissue and acidic fluid pH. For this reason, a combination medication with both meloxicam and bupivacaine has been developed, which normalizes pH and has anti-inflammatory and anti-pain conduction properties. Clinical studies demonstrate that this combination agent can be extremely beneficial in treating postoperative pain. This manuscript summarizes the newest developments with regard to liposomal bupivacaine and the non-steroidal meloxicam, their roles in effective treatment of postoperative pain, contraindications, special considerations of using these medications, and future considerations. HTX-011 pairs up a new extended-release formulation of the local anesthetic bupivacaine with meloxicam, a well-established non-steroidal anti-inflammatory drug (NSAID).

Intraoperative Intracavernosal Liposomal Bupivacaine (Exparel) Injection Does Not Affect Systemic Hemodynamics

INTRODUCTION

The systemic effect of intracavernosal liposomal bupivacaine (Exparel) injection during inflatable penile prosthesis (IPP) implantation on systemic hemodynamics has not been clarified.

AIM

To evaluate whether intraoperative intracavernosal Exparel injection affects systemic hemodynamics.

METHODS

We studied 56 consecutive patients who underwent IPP implantation under general anesthesia using the transverse scrotal approach. Exparel [10 mL of 1.3% (13.3 mg/mL)] was instilled bilaterally intracavernosally via a 25-gauge needle around 30 min after starting the surgery. All patients graded their postoperative pain using a standard 10-point scale.

MAIN OUTCOME MEASURE

Perioperative vital signs at defined time intervals and postoperative pain were monitored. The degree of postoperative pain were analyzed using a standard 10-point scale.

RESULTS

Medians and interquartile ranges (IQRs) of the patients' age [64 years (57.3-69.3)], operation time [85 min (78-96)], and estimated blood loss [75 mL (29-100)] were recorded. Although the median preoperative systolic noninvasively measured blood pressure of 131 mm/Hg (IQR: 122-139) fell by 25% to 98 mm/Hg (IQR: 90-100) (P < .001) after anesthesia started, there was no significant decrease in blood pressure between before and after Exparel injection. The perioperative pulse rate and pulse oximetry oxygen saturation were stable. Neither arrhythmia nor convulsion occurred. Patients reported postoperative pain as 0 (IQR: 0-2.25) on a scale of 0-10.

CLINICAL IMPLICATIONS

Intraoperative intracavernosal Exparel injection is safe and effective in patients undergoing IPP implantation surgery.

STRENGTH & LIMITATIONS

This is the first report to describe systemic hemodynamics of intracavernosal Exparel injection. Limitations are lack of blood concentration of Exparel at various time points and long-term follow-up for pain assessment.

CONCLUSION

Although limited by a lack of the blood concentration of Exparel and short follow-up for pain assessment, we concluded that intraoperative intracavernosal Exparel injection does not affect systemic hemodynamics. Taniguchi H, Mulhall JP. Intraoperative Intracavernosal Liposomal Bupivacaine (Exparel) Injection Does Not Affect Systemic Hemodynamics. J Sex Med 2020;17:526-530.

Nanomedicines Lost in Translation

Nanomedicines have historically struggled to find clinical relevance and to achieve translation successfully. In this Perspective, we discuss possible reasons for this difficulty and highlight several key features of nanomedicines that are often overlooked by biomedical engineers. We present the notion of clinical multifunctionality as distinct from multifunctionality as it is traditionally described at the nanoscale and emphasize its importance through examples of nanomedicines that have demonstrated emergent clinical multifunctionality once translated. We also describe a phenomenon in which clinical multifunctionality results in diagonal translation after a nanomedicine is adopted by clinicians to serve as a solution for a clinical problem that it was not designed to solve. Biomedical engineers can take advantage of these phenomena to assist in achieving clinical translation of new nanomedicines.

Regional anaesthesia for surgical repair of proximal humerus fractures: a systematic review and critical appraisal

INTRODUCTION

Regional anaesthesia (RA) is often used in shoulder surgery because it provides adequate postoperative analgesia and may enhance the patient outcome. RA reduces overall opioid consumption and is frequently used in enhanced recovery programs to decrease hospital stay. However, there is very limited literature confirming these advantages in the surgical repair of proximal humerus fractures. This paper reviews the current literature on the use of RA in pain management after surgical repair of these fractures and evaluates the effect of RA on the functional outcome, length of stay in hospital, and health care expenditure.

MATERIALS AND METHODS

The PubMed, Embase, Web of Science, and Cochrane Library databases were searched up to March 1, 2018. Studies investigating the use of RA in the management of proximal humerus fractures were included.

RESULTS

Eleven studies (containing 1872 patients) were eligible for inclusion. The analgesic effect of RA was investigated in eight studies that confirmed its pain-relieving ability. Two studies measured functionality and length of hospitalization and suggested that RA improved function and shortened the stay in hospital. Nine papers mentioned side effects associated with RA while three articles claim that RA decreases the incidence of adverse events associated with general anaesthesia.

CONCLUSIONS

This systematic review suggests that RA is a good option for postoperative analgesia in patients undergoing surgical repair of a proximal humerus fracture and is associated with fewer adverse events, a shorter recovery time, and a better functional outcome than those achieved by general anaesthesia alone. However, given the limited amount of data available, conclusions need to be made with caution and prospective studies are needed in the future.

HTX-011 reduced pain intensity and opioid consumption versus bupivacaine HCl in herniorrhaphy: results from the phase 3 EPOCH 2 study

Purpose

Currently available local anesthetics have not demonstrated sufficient analgesia beyond 12–24 h postoperatively. The purpose of the study was to assess the safety and efficacy of HTX-011 (bupivacaine and meloxicam in Biochronomer^® polymer technology), a long-acting investigational anesthetic, in reducing both postoperative pain over 72 h and postoperative opioid use compared to bupivacaine hydrochloride (HCl).

Methods

A phase 3, randomized, double-blind, active-controlled multi-center study (EPOCH 2; NCT03237481) in subjects undergoing unilateral open inguinal herniorrhaphy with mesh placement was performed. Subjects randomly received a single intraoperative dose of HTX-011, immediate-release bupivacaine HCl, or saline placebo prior to closure.

Results

The study evaluated 418 subjects, and the primary and all key secondary efficacy endpoints were in favor of HTX-011. HTX-011 reduced mean pain intensity by 23% versus placebo (primary endpoint; p < 0.001) and by 21% versus bupivacaine HCl (p < 0.001) with significant reductions in the number of patients experiencing severe pain. Opioid consumption over 72 h was reduced by 38% versus placebo (p < 0.001) and 25% versus bupivacaine HCl (p = 0.024). Overall, 51% of HTX-011 subjects were opioid-free through 72 h (versus 22% for placebo [p < 0.001] and 40% for bupivacaine HCl [p = 0.049]). HTX-011 was generally well-tolerated with fewer opioid-related adverse events reported compared to the bupivacaine HCl and placebo and no evidence of local anesthetic systemic toxicity.

Conclusions

HTX-011 demonstrated significant improvement in postoperative pain control and a clinically meaningful reduction in opioid consumption when compared to the most widely used local anesthetic, bupivacaine HCl.

Application of TAP Block in Laparoscopic Urological Surgery: Current Status and Future Directions

PURPOSE OF REVIEW

Amid the opioid crisis, postoperative pain management is a major challenge for practitioners. Recent pain management guidelines emphasize the importance of using regional anesthesia as part of opioid-sparing multimodal analgesia. This report aims to review recent evidence regarding the utilization of transversus abdominis plane (TAP) block in minimally invasive urologic surgery.

RECENT FINDINGS

TAP block has been shown to improve early and late pain at rest, and to reduce opioid consumption after minimally invasive surgery. These benefits have indirectly reduced the incidence of postoperative delirium, pneumonia, urinary retention, and falls. Compared to epidural analgesia, TAP block provides similar pain control, has a lower incidence of hypotension, and is associated with a shorter length of stay. Few studies focus specifically on the outcomes of TAP block in minimally invasive urologic surgery. TAP block decreases postoperative pain and reduces opioid consumption without increasing complications. TAP block should be integrated as an indispensable component in enhanced recovery after surgery protocols.

EMMEZ H, ULUDAĞ O, BAL NB, DEĞİM T. Antinociceptive Effect of Liposomal Bupivacaine Formulations After Intrathecal Administration in Rats

Background/aim

Based on our previous in vitro study with multilamellar liposomal bupivacaine (MLB) versus bupivacaine alone in artificial cerebrospinal fluid, we aimed to investigate in vivo antinociceptive effect of intrathecal MLB by determining tail flick latency (TFL) time after thermal stimulation in rats.

Materials and methods

After preparing MLB and high-yield drug entrapment in liposome (HYDEL) bupivacaine, 18 female Wistar rats were assigned to 3 groups as control (bupivacaine) and study groups (MLB and HYDEL bupivacaine) including 6 rats in each group to administer these drugs intrathecally. Antinociceptive activity was determined in terms of TFL time after thermal stimulation. Maximum possible effect (MPE) calculated from TFL times and rats with motor block were documented.

Results

TFL times after intrathecal injection of HYDEL bupivacaine were significantly longer than that of the control and MLB groups (P < 0.05) and returned to baseline 180 min after intrathecal injection. MPE (100%) with intrathecal HYDEL bupivacaine occurred between 10 to 45 min. Afterwards, MPEs were 70% and 50% for the control and MLB groups, respectively. Motor block disappeared after 20 min in the study groups while it lasted 75 min in the control.

Conclusion

Intrathecal administration of MLB and HYDEL bupivacaine in rats resulted in longer duration of antinociceptive activity with shorter motor block duration.

A Comprehensive Map of FDA-Approved Pharmaceutical Products

With the increasing research and development (R&D) difficulty of new molecular entities (NMEs), novel drug delivery systems (DDSs) are attracting widespread attention. This review investigated the current distribution of Food and Drug Administration (FDA)-approved pharmaceutical products and evaluated the technical barrier for the entry of generic drugs and highlighted the success and failure of advanced drug delivery systems. According to the ratio of generic to new drugs and the four-quadrant classification scheme for evaluating the commercialization potential of DDSs, the results showed that the traditional dosage forms (e.g., conventional tablets, capsules and injections) with a lower technology barrier were easier to reproduce, while advanced drug delivery systems (e.g., inhalations and nanomedicines) with highly technical barriers had less competition and greater market potential. Our study provides a comprehensive insight into FDA-approved products and deep analysis of the technical barriers for advanced drug delivery systems. In the future, the R&D of new molecular entities may combine advanced delivery technologies to make drug candidates into more therapeutically effective formulations.

Injectable nanocomposite analgesic delivery system for musculoskeletal pain management

Musculoskeletal pain is a major health issue which results from surgical procedures (i.e. total knee and/or hip replacements and rotator cuff repairs), as well as from non-surgical conditions (i.e. sympathetically-mediated pain syndrome and occipital neuralgia). Local anesthetics, opioids or corticosteroids are currently used for the pain management of musculoskeletal conditions. Even though local anesthetics are highly preferred, the need for multiple administration presents significant disadvantages. Development of unique delivery systems that can deliver local anesthetics at the injection site for prolonged time could significantly enhance the therapeutic efficacy and patient comfort. The goal of the present study is to evaluate the efficacy of an injectable local anesthetic nanocomposite carrier to provide sustained analgesic effect. The nanocomposite carrier was developed by encapsulating ropivacaine, a local anesthetic, in lipid nanocapsules (LNC-Rop), and incorporating the nanocapsules in enzymatically crosslinked glycol chitosan (0.3GC) hydrogels. Cryo Scanning Electron Microscopic (Cryo SEM) images showed the ability to distribute the LNCs within the hydrogel without adversely affecting their morphology. The study demonstrated the feasibility to achieve sustained release of lipophilic molecules from the nanocomposite carrier in vitro and in vivo. A rat chronic constriction injury (CCI) pain model was used to evaluate the efficacy of the nanocomposite carrier using thermal paw withdrawal latency (TWL). The nanocomposite carriers loaded with ropivacaine and dexamethasone showed significant improvement in pain response compared to the control groups for at least 7 days. The study demonstrated the clinical potential of these nanocomposite carriers for post-operative and neuropathic pain.

STATEMENT OF SIGNIFICANCE

Acute or chronic pain associated with musculoskeletal conditions is considered a major health issue, with healthcare costs totaling several billion dollars. The opioid crisis presents a pressing clinical need to develop alternative and effective approaches to treat musculoskeletal pain. The goal of this study was to develop a long-acting injectable anesthetic formulation which can sustain a local anesthetic effect for a prolonged time. This in turn could increase the quality of life and rehabilitation outcome of patients, and decrease opioid consumption. The developed injectable nanocomposite demonstrated the feasibility to achieve prolonged pain relief in a rat chronic constriction injury (CCI) model.

Systematic review and meta-analysis of the efficacy of liposomal bupivacaine in colorectal resections

Objective: The objective of the study was to systematically investigate the outcomes of Liposomal Bupivacaine following major colorectal resections. Patients and methods: We conducted a comprehensive literature search of PubMed, Medline, Google scholar, Cochrane Central Registry and clinical trials.gov databases through May 2017 for studies published regarding liposomal bupivacaine. Studies were filtered based on relevance to perioperative analgesia in colorectal resections. Data comparing type of study, techniques of resection, mode of administration of liposomal bupivacaine, details of control group, outcomes were collected. Results: A total of 1008 patients from seven studies were included in this systematic review and meta-analysis. The studies were mostly retrospective or prospective cohort studies with one randomized controlled trial (RCT). Meta-analysis showed that liposomal bupivacaine was associated with decreased length of stay, standard mean difference in days (SMD) - 0.34, (95% confidence intervals [CI] - 0.56, -0.13, p = .001) and decreased IV opioid use (expressed as intravenous morphine equivalent in milligrams) in the first 48-72 h, SMD -0.49 (95% CI -0.69, -0.28, p < .00001). Pain scores were also significantly low in patients who received liposomal bupivacaine, SMD -0.56 (95% CI -1.07, -0.06, p = .03]. There was no significant difference in hospitalization costs between the two groups. Conclusions: Use of liposomal bupivacaine is associated with decreased IV opioid use, length of stay and lower pain scores. However, our data needs to be interpreted cautiously given the relative paucity of randomized controlled trials.

Liposomal Bupivacaine Use in Third Molar Impaction Surgery: INNOVATE Study

The analgesic efficacy and safety of liposomal bupivacaine (LB) in third molar extraction was evaluated in this phase 3, double-blind, placebo-controlled study of subjects undergoing bilateral third molar extraction. Subjects were randomized 2 : 1 to infiltration with LB (133 mg/10 mL) or placebo, and received opioid rescue medication as needed. Primary efficacy measure was cumulative area under the curve (AUC) of numeric rating scale (NRS) pain severity scores through 48 hours (AUC of NRS_0-48) postsurgery. Other measures included AUC of NRS_0-24, AUC of NRS_0-72, and AUC of NRS_0-96, and incidence of adverse events. There were 150 subjects in the primary efficacy population (n = 99 LB, n = 51 placebo) and 89 in the per-protocol population (n = 59 LB, n = 30 placebo). Least-squares mean for AUC of NRS_0-48 was 172.3 LB versus 194.7 placebo (P = .227) in the primary efficacy population and 120.8 LB versus 183.3 placebo (P = .023) in the per-protocol population. At all time points, between-group differences in AUC of NRS scores were significant in the per-protocol population (LB lower than placebo, P < .05) but not in the primary efficacy population. The adverse event profile was similar between groups. LB produced significantly lower cumulative pain scores versus placebo at all time points in the per-protocol analysis but not in the primary efficacy analysis because of protocol violations. This study indicates significant improvement in pain scores in the third molar model, but because of extensive protocol violations additional studies are warranted to demonstrate effectiveness.