Perineural Liposomal Bupivacaine Is Not Superior to Nonliposomal Bupivacaine for Peripheral Nerve Block Analgesia

Safety and Efficacy of Vocacapsaicin for Management of Postsurgical Pain: A Randomized Clinical Trial

BACKGROUND

Nonopioid management of postsurgical pain remains a major unmet need. Few studies have evaluated transient receptor potential vanilloid subfamily member 1 agonists for analgesia after surgery. This study examines intraoperative vocacapsaicin, a novel prodrug of the transient receptor potential vanilloid subfamily member 1 agonist capsaicin, in a validated model of postsurgical pain.

METHODS

This was a triple-blinded, randomized, placebo-controlled, dose-ranging trial in patients undergoing bunionectomy. Patients were randomized 1:1:1:1 to surgical site administration of 14 ml of placebo or one of three vocacapsaicin concentrations: 0.30, 0.15, or 0.05 mg/ml. The prespecified primary endpoint was the area-under-the-curve of the numerical rating scale pain score at rest through 96 h for the 0.30 mg/ml group. Prespecified ordered, secondary endpoints for the 0.30 mg/ml group included the percentage of patients who did not require opioids from 0 to 96 h, total opioid consumption through 96 h, and the area-under-the-curve of the numerical rating scale pain score for the first week.

RESULTS

The 147 patients were randomized. During the first 96 h, vocacapsaicin (0.30 mg/ml) reduced pain at rest by 33% versus placebo (primary endpoint, 95% CI [10%, 52%], effect size [Cohen's d] = 0.61, P = 0.005). Of patients receiving vocacapsaicin (0.30 mg/ml), 26% did not require postoperative opioids for analgesia (P = 0.025) versus 5% of patients receiving placebo. Vocacapsaicin (0.30 mg/ml) reduced opioid consumption over the first 96 h by 50% versus placebo (95% CI [26%, 67%], effect size = 0.76, P = 0.002). Vocacapsaicin (0.30 mg/ml) reduced pain over the first week by 37% versus placebo (95% CI [12%, 57%], effect size = 0.62, P = 0.004). The treatment effect persisted for at least 2 weeks. All study endpoints showed an administered concentration-versus-response relationship. Vocacapsaicin was well tolerated with no differences between groups in any safety parameter.

CONCLUSIONS

A single, local administration of vocacapsaicin during surgery reduced pain and opioid consumption for at least 96 h after surgery compared to control.

EDITOR’S PERSPECTIVE

Combined pectoralis and serratus anterior plane blocks with or without liposomal bupivacaine for minimally invasive thoracic surgery: A randomized clinical trial

BACKGROUND

Minimally invasive thoracic surgery is associated with substantial pain that can impair pulmonary function. Fascial plane blocks may offer a favorable alternative to opioids, but conventional local anesthetics provide a limited duration of analgesia. We therefore tested the primary hypothesis that a mixture of liposomal bupivacaine and plain bupivacaine improves the overall benefit of analgesia score (OBAS) during the first three postoperative days compared to bupivacaine alone. Secondarily, we tested the hypotheses that liposomal bupivacaine improves respiratory mechanics, and decreases opioid consumption.

METHODS

Adults scheduled for robotically or video-assisted thoracic surgery with combined ultrasound-guided pectoralis II and serratus anterior plane block were randomized to bupivacaine or bupivacaine combined with liposomal bupivacaine. OBAS was measured on postoperative days 1-3 and was analyzed with a linear mixed regression model. Postoperative respiratory mechanics were estimated using a linear mixed model. Total opioid consumption was estimated with a simple linear regression model.

RESULTS

We analyzed 189 patients, of whom 95 were randomized to the treatment group and 94 to the control group. There was no significant treatment effect on total OBAS during the initial three postoperative days, with an estimated geometric mean ratio of 0.93 (95% CI: 0.76, 1.14; p = 0.485). There was no observed treatment effect on respiratory mechanics, total opioid consumption, or pain scores. Average pain scores were low in both groups.

CONCLUSIONS

Liposomal bupivacaine did not improve OBAS during the initial postoperative three days following minimally invasive thoracic procedures. Furthermore, there was no improvement in respiratory mechanics, no reduction in opioid consumption, and no decrease in pain scores. Thus, the data presented here does not support the use of liposomal bupivacaine over standard bupivacaine to enhance analgesia after minimally invasive thoracic surgery.

SUMMARY STATEMENT

For minimally invasive thoracic procedures, addition of liposomal bupivacaine to plain bupivacaine for thoracic fascial plane blocks does not improve OBAS, reduce opioid requirements, improve postoperative respiratory mechanics, or decrease pain scores.

Association Between Single-Injection Regional Analgesia and Postoperative Pain in Cardiac Surgery Patients: A Single-Center Retrospective Cohort Study

OBJECTIVES

Effective pain control after cardiac surgery may facilitate recovery. This study aimed to assess the use and association of ultrasound-guided single-injection chest wall blocks with liposomal bupivacaine on postoperative pain scores and short-term opioid requirements after cardiothoracic surgery at a single institution.

DESIGN

Retrospective cohort study.

SETTING

Midwestern academic hospital.

PARTICIPANTS

Adult patients who underwent cardiothoracic surgery between July 1, 2020, and June 30, 2022.

INTERVENTIONS

Ultrasound-guided single-injection chest wall block with liposomal bupivacaine.

MEASUREMENTS AND MAIN RESULTS

Of the 1,038 patients included in this study, 301 (29%) received a perioperative nerve block for postoperative sternotomy pain, and 737 (71%) did not. Most of the single-shot blocks were bilateral parasternal intercostal plane blocks (n = 294 [98%]) performed after induction and before surgical incision (n = 280 [93%]). After adjusting for age, gender, American Society of Anesthesiologists status, select comorbidities, and surgical procedure type, mean postoperative pain scores were not significantly different between groups in the immediate postoperative period at all time points assessed (12 ± 2 hours, 24 ± 4 hours, 48 ± 8 hours, and 72 ± 12 hours). Similarly, there was no difference in mean opioid requirements (milligram morphine equivalents) at 72 hours between groups (68.6 [95% confidence interval, 56.3-83.4] vs 62.9 [95% confidence interval, 52.8-74.9], p = 0.195).

CONCLUSIONS

In this retrospective study, the implementation of single-shot chest wall nerve blocks with liposomal bupivacaine was not associated with decreased postoperative pain scores or opioid consumption at 72 hours in select cardiac surgical patients at one institution.

Liposomal bupivacaine provides superior pain control compared to bupivacaine with adjuvants in interscalene block for total shoulder replacement: a prospective double-blinded, randomized controlled trial

INTRODUCTION

Optimal pain control methods after total shoulder arthroplasty (TSA) achieve reduced opioid consumption, shortened hospital stay, and improved patient satisfaction in addition to adequate analgesia. Interscalene brachial plexus block is the gold standard for TSA, yet it typically does not provide pain relief lasting beyond 24 hours. Liposomal bupivacaine (LB) purportedly provides prolonged analgesia, yet it has been minimally explored for interscalene block, and it is significantly more expensive than standard bupivacaine.

METHODS

This is a prospective, 2-arm, double-blinded randomized controlled trial. Subjects presenting for anatomic or reverse TSA were randomized in a 1:1 ratio to receive interscalene brachial plexus block with either LB plus bupivacaine (LBB group) or bupivacaine plus dexamethasone and epinephrine (BDE group). The primary outcome was 120-hour postoperative opioid consumption. Secondary outcomes were pain scores up to 96 hours postoperatively, pain control satisfaction, complications, level of distress from block numbness, and hospital stay.

RESULTS

Ninety patients, 45 per group, were included in the intention-to-treat analysis and randomized. Because of withdrawal of consent and loss to follow-up, 40 in each group completed enrollment through postoperative day 60. Total 120-hour postoperative opioid consumption was similar between groups (P = .127), with no differences within 24- or 48-hour time intervals. Postoperative pain scores at 24-48 hours, 48-72 hours, 72-96 hours, and day 60 were significantly lower for the LBB group.

DISCUSSION

LB interscalene brachial plexus block before total shoulder arthroplasty did not reduce 120-hour postoperative opioid consumption but significantly reduced postoperative pain between 24 and 96 hours and at postoperative day 60.

Liposomal Bupivacaine for Peripheral Nerve Blockade: A Randomized, Controlled, Crossover, Triple-blinded Pharmacodynamic Study in Volunteers

BACKGROUND

Little is known about the pharmacodynamic characteristics of liposomal bupivacaine. Hypothesizing that they would not identify pharmacodynamic differences from plain bupivacaine during the initial period after administration, but would find better long-term pharmacodynamic characteristics, the authors designed a randomized, controlled, triple-blinded, single-center study in volunteers.

METHODS

Volunteers aged 18 to 55 yr (body mass index, 18 to 35 kg/m2) received two ulnar nerve blocks under ultrasound guidance. Using a crossover design with a washout phase of 36 days or more, one block was performed with liposomal and one with plain bupivacaine. Which came first was determined by randomization. Sensory data were collected by pinprick testing and motor data by thumb adduction, either way in comparison with the contralateral arm. Endpoints included success, time to onset, and duration of blockade. Residual efficacy was assessed by the volunteers keeping a diary. Statistical analysis included Wilcoxon signed-rank and exact McNemar's tests, as well as a generalized estimation equation model.

RESULTS

Successful sensory blockade was noted in 8 of 25 volunteers (32%) after liposomal and in 25 of 25 (100%) after plain bupivacaine (P < 0.0001). Significant differences emerged for time to onset, defined as 0% response to pinpricking in four of five hypothenar supply areas (P < 0.0001), and for time from onset to 80% or 20% in one of five areas (P < 0.001; P < 0.001). Carryover effects due to the randomized sequencing were unlikely (estimate, -0.6286; sequence effect, 0.8772; P = 0.474). Self-assessment greater than 3.5 days did reveal, for liposomal bupivacaine only, intermittent but unpredictable episodes of residual sensory blockade.

CONCLUSIONS

The results show that liposomal bupivacaine is not a suitable "sole" drug for intraoperative regional anesthesia. Findings of its limited long-term efficacy add to existing evidence that a moderate effect, at best, should be expected on postoperative pain therapy.

EDITOR’S PERSPECTIVE

Local Anesthetics, Local Anesthetic Systemic Toxicity (LAST), and Liposomal Bupivacaine

Local anesthetics have played a vital role in the multimodal analgesia approach to patient care by decreasing the use of perioperative opioids, enhancing patient satisfaction, decreasing the incidence of postoperative nausea and vomiting, decreasing the length of hospital stay, and reducing the risk of chronic postsurgical pain. The opioid-reduced anesthetic management for perioperative analgesia has been largely successful with the use of local anesthetics during procedures such as peripheral nerve blocks and neuraxial analgesia. It is important that practitioners who use local anesthetics are aware of the risk factors, presentation, and management of local anesthetic systemic toxicity (LAST).

Postoperative pain scores and opioid use after standard bupivacaine vs. liposomal bupivacaine regional blocks for abdominal cancer surgery: A propensity score matched study

BACKGROUND

Fascial plane blocks (FPBs) are widely used for abdominal surgery with the assumption that liposomal bupivacaine (LB) is more effective than standard bupivacaine (SB).

METHODS

This was a single-institution retrospective cohort study of patients administered FPBs with LB or SB ​+ ​admixtures (dexamethasone/dexmedetomidine) for open abdominal cancer surgery. Propensity score matching generated a 2:1 (LB:SB) matched cohort. Opioid use (mg oral morphine equivalents, OME) and severe pain (≥3 pain scores ≥7 in a 24-h period) were compared.

RESULTS

Opioid use was >150 ​mg OME in 19.9 ​% (29/146) LB and 16.4 ​% (12/73) SB patients (p ​= ​0.586). Severe pain was experienced by 44 ​% (64/146) LB and 53 ​% (39/73) SB patients (p ​= ​0.198). On multivariable analysis, SB vs LB choice was not associated with high opioid volume >150 ​mg or severe pain.

CONCLUSIONS

FPBs with standard bupivacaine were not associated with higher 72-h opioid use or more severe pain compared to liposomal bupivacaine.

Dose safety and pharmacodynamics of subcutaneous bupivacaine in a novel extended-release microparticle formulation: A phase 1, dose-ascending study in male volunteers

A novel microparticle-based extended-release local anaesthetic containing a bupivacaine/poly-lactic-co-glycolic acid (PLGA; LIQ865A) or plain bupivacaine (LIQ865B) was examined in a first-in-human trial. The objectives were to examine the dose safety/tolerability and pharmacodynamics. Randomized subcutaneous injections of LIQ865A (n = 16) or LIQ865B (n = 12) and diluent, contralaterally, were administered in a dose-ascending manner (150- to 600-mg bupivacaine). Subjects were admitted 24 h post-injection and followed for 30 days post-injection. The risk ratios (RRs; 95% CI) of erythematous reactions for LIQ865A versus diluent was 9.00 (1.81-52.23; P = 0.006) and for LIQ865B versus diluent 2.50 (0.69-9.94; P = 0.37). The RR for the development of hematomas (LIQ865A versus diluent) were 3.25 (1.52-8.16; P = 0.004) and 4.00 (0.72-24.89; P = 0.32) (LIQ865B versus diluent). Subcutaneous indurations persisting for 4-13 weeks were seen in 6/16 subjects receiving LIQ865A. One subject receiving LIQ865A (600-mg bupivacaine) developed intermittent central nervous system (CNS) symptoms of local anaesthetic systemic toxicity (85 min to 51 h post-injection) coinciding with plasma peak bupivacaine concentrations (490-533 ng/ml). Both LIQ865 formulations demonstrated dose-dependent hypoesthesia and hypoalgesia. The duration of analgesia ranged between 37 and 86 h. The overall number of local adverse events, however, prohibits clinical application without further pharmacological modifications.

Use of lateral femoral cutaneous nerve blocks by landmark technique is ineffective in decreasing narcotic usage after skin grafts: A retrospective case-control study

INTRODUCTION

Cutaneous burns are commonly treated with autologous skin grafts. Following skin grafting, many patients complain of pain at the donor site. Donor sites are taken most commonly from the lateral thigh, which is innervated by the lateral femoral cutaneous nerve (LFCN). Use of a LFCN blocks should decrease nociception from the donor site.

METHODS

Our group began utilizing LFCN blocks in 2019. Utilizing anatomic landmarks, LFCN blocks were performed on all patients who received autologous skin grafts to reduce perioperative pain. A retrospective cohort study was performed on all patients with 10% or less total body surface areas burns who received an autologous skin graft. A similar cohort from 2016, prior to use of any local or regional analgesia, was used as a historical control. Post-operative enteral and parenteral narcotic analgesics were collected for each post-operative day up to day 5 or discharge (whichever came first) and converted to morphine milligram equivalents (MME) to quantify analgesia after surgery.

RESULTS

Chart review identified 55 patients in the 2020 cohort. Fifty-five patients from the 2016 cohort were matched based upon size of skin graft, total body surface area (TBSA) burned, gender, and age. There were no statistically significant differences between the two groups in terms of size of graft, TBSA burned, age, gender, or type of burn. When examining narcotics usage in the immediate perioperative period (days 0-2), we found no difference between the two groups for total MME (113 vs 133, p = 0.28) or IV MME (38 vs 33, p = 0.45). Similar relationships existed in the extended post-operative period (days 1-5) for total MME (149 vs. 188, t = 0.22) or IV MME (37 vs. 50, t = 0.25). Examining daily narcotic usage also yielded no statistically different values.

CONCLUSION

Our data shows that use of LFCN block by landmark technique did not reduce narcotic usage in patients that undergo skin grafting procedures. Future studies should consider ultrasound-guided LFCN blocks.

Population pharmacokinetic-pharmacodynamic model of subcutaneous bupivacaine in a novel extended-release microparticle formulation

The objective of this study was to develop a population pharmacokinetic-pharmacodynamic model of subcutaneously administered bupivacaine in a novel extended-release microparticle formulation for postoperative pain management. Bupivacaine was administered subcutaneously in the lower leg to 28 healthy male subjects in doses from 150 to 600 mg in a phase 1 randomized, placebo-controlled, double-blind, dose-ascending study with two different microparticle formulations, LIQ865A and LIQ865B. Warmth detection threshold was used as a surrogate pharmacodynamic endpoint. Population pharmacokinetic-pharmacodynamic models were fitted to plasma concentration-effect-time data using non-linear mixed-effects modelling. The pharmacokinetics were best described by a two-compartment model with biphasic absorption as two parallel absorption processes: a fast, zero-order process and a slower, first-order process with two transit compartments. The slow absorption process was found to be dose-dependent and rate-limiting for elimination at higher doses. Apparent bupivacaine clearance and the transit rate constant describing the slow absorption process both appeared to decrease with increasing doses following a power function with a shared covariate effect. The pharmacokinetic-pharmacodynamic relationship between plasma concentrations and effect was best described by a linear function. This model gives new insight into the pharmacokinetics and pharmacodynamics of microparticle formulations of bupivacaine and the biphasic absorption seen for several local anaesthetics.

Analgesic Effectiveness of Liposomal Bupivacaine versus Plain Local Anesthetics for Abdominal Fascial Plane Blocks: A Systematic Review and Meta-analysis of Randomized Trials

BACKGROUND

Liposomal bupivacaine is reported to prolong the duration of analgesia when used for abdominal fascial plane blocks compared to plain local anesthetics; however, evidence from randomized trials is mixed. This meta-analysis aims to compare the analgesic effectiveness of liposomal bupivacaine to plain local anesthetics in adults receiving abdominal fascial plane blocks.

METHODS

Randomized trials comparing liposomal bupivacaine and plain (nonliposomal) local anesthetics in abdominal fascial plane blocks were sought. The primary outcome was area under the curve rest pain between 24 to 72 h postoperatively. Secondary outcomes included rest pain at individual timepoints (1, 6, 12, 24, 48, and 72 h); analgesic consumption at 0 to 24, 25 to 48, and 49 to 72 h; time to analgesic request; hospital stay duration; and opioid-related side effects. Data were pooled using the Hartung-Knapp-Sidik-Jonkman random effects method.

RESULTS

Sixteen trials encompassing 1,287 patients (liposomal bupivacaine, 667; plain local anesthetics, 620) were included. The liposomal bupivacaine group received liposomal bupivacaine mixed with plain bupivacaine in 10 studies, liposomal bupivacaine alone in 5 studies, and both preparations in 1 three-armed study. No difference was observed between the two groups for area under the curve pain scores, with a standardized mean difference (95% CI) of -0.21 cm.h (-0.43 to 0.01; P = 0.058; I2 = 48%). Results were robust to subgroup analysis based on (1) potential conflict of interest and (2) mixing of plain local anesthetics with liposomal bupivacaine. The two groups were not different for any of the day 2 or day 3 secondary outcomes.

CONCLUSIONS

This systematic review and meta-analysis suggests similar analgesic effectiveness between liposomal bupivacaine and plain local anesthetics when used for fascial plane block of the abdominal wall. The authors' analysis does not support an evidence-based preference for liposomal bupivacaine compared to plain local anesthetics for abdominal fascial plane blocks.

EDITOR’S PERSPECTIVE

Nanotechnology for Pain Management

Introduction: In the context of the current opioid crisis, non-pharmacologic approaches to pain management have been considered important alternatives to the use of opioids or analgesics. Advancements in nano and quantum technology have led to the development of several nanotransporters, including nanoparticles, micelles, quantum dots, liposomes, nanofibers, and nano-scaffolds. These modes of nanotransporters have led to the development of new drug formulations. In pain medicine, new liposome formulations led to the development of DepoFoam™ introduced by Pacira Pharmaceutical, Inc. (Parsippany, NJ, USA). This formulation is the base of DepoDur™, which comprises a combination of liposomes and extended-release morphine, and Exparel™, which comprises a combination of liposomes and extended-release bupivacaine. In 2021, Heron Therapeutics (San Diego, CA, USA) created Zynrelef™, a mixture of bupivacaine and meloxicam. Advancements in nanotechnology have led to the development of devices/patches containing millions of nanocapacitors. Data suggest that these nanotechnology-based devices/patches reduce acute and chronic pain. Methods: Google and PubMed searches were conducted to identify studies, case reports, and reviews of medical nanotechnology applications with a special focus on acute and chronic pain. This search was based on the use of keywords like nanotechnology, nano and quantum technology, nanoparticles, micelles, quantum dots, liposomes, nanofibers, nano-scaffolds, acute and chronic pain, and analgesics. This review focuses on the role of nanotechnology in acute and chronic pain. Results: (1) Nanotechnology-based transporters. DepoDur™, administered epidurally in 15, 20, or 25 mg single doses, has been demonstrated to produce significant analgesia lasting up to 48 h. Exparel™ is infiltrated at the surgical site at the recommended dose of 106 mg for bunionectomy, 266 mg for hemorrhoidectomy, 133 mg for shoulder surgery, and 266 mg for total knee arthroplasty (TKA). Exparel™ is also approved for peripheral nerve blocks, including interscalene, sciatic at the popliteal fossa, and adductor canal blocks. The injection of Exparel™ is usually preceded by an injection of plain bupivacaine to initiate analgesia before bupivacaine is released in enough quantity from the depofoarm to be pharmacodynamically effective. Finally, Zynrelef™ is applied at the surgical site during closure. It was initially approved for open inguinal hernia, abdominal surgery requiring a small-to-medium incision, foot surgery, and TKA. (2) Nanotechnology-based devices/patches. Two studies support the use of nanocapacitor-based devices/patches for the management of acute and chronic pain. A randomized study conducted on patients undergoing unilateral primary total knee (TKA) and total hip arthroplasty (THA) provided insight into the potential value of nanocapacitor-based technology for the control of postoperative acute pain. The results were based on 2 studies, one observational and one randomized. The observational study was conducted in 128 patients experiencing chronic pain for at least one year. This study suggested that compared to baseline, the application of a nanocapacitor-based Kailo™ pain relief patch on the pain site for 30 days led to a time-dependent decrease in pain and analgesic use and an increase in well-being. The randomized study compared the effects of standard of care treatment to those of the same standard of care approach plus the use of two nanocapacitor-based device/patches (NeuroCuple™ device) placed in the recovery room and kept in place for three days. The study demonstrated that the use of the two NeuroCuple™ devices was associated with a 41% reduction in pain at rest and a 52% decrease in the number of opioid refills requested by patients over the first 30 days after discharge from the hospital. Discussion: For the management of pain, the use of nano-based technology has led to the development of nano transporters, especially focus on the use of liposome and nanocapacitors. The use of liposome led to the development of DepoDur™, bupivacaine Exparel™ and a mixture of bupivacaine and meloxicam (Zynrelef™) and more recently lidocaine liposome formulation. In these cases, the technology is used to prolong the duration of action of drugs included in the preparation. Another indication of nanotechnology is the development of nanocapacitor device or patches. Although, data obtained with the use of nanocapacitors are still limited, evidence suggests that the use of nanocapacitors devices/patches may be interesting for the treatment of both acute and chronic pain, since the studies conducted with the NeuroCuple™ device and the based Kailo™ pain relief patch were not placebo-controlled, it is clear that additional placebo studies are required to confirm these preliminary results. Therefore, the development of a placebo devices/patches is necessary. Conclusions: Increasing evidence supports the concept that nanotechnology may represent a valuable tool as a drug transporter including liposomes and as a nanocapacitor-based device/patch to reduce or even eliminate the use of opioids in surgical patients. However, more studies are required to confirm this concept, especially with the use of nanotechnology incorporated in devices/patches.

Effects of transcutaneous electrical acupoint stimulation on early postoperative pain and recovery: a comprehensive systematic review and meta-analysis of randomized controlled trials

Background

Previous studies have indicated beneficial outcomes of transcutaneous electrical acupoint stimulation (TEAS), but high-quality and comprehensive meta-analyses are lacking. The aim was to quantitatively analyze the efficacy and safety of perioperative TEAS on postoperative pain and recovery.

Methods

PubMed, Web of Science, EMBASE, and the Cochrane Library were searched through July 2022. Randomized controlled trials (RCTs) that examined the perioperative application of TEAS in adults compared with sham-TEAS and/or non-TEAS were eligible. Cumulative analgesic consumption within 24 h and rest pain scores at 2, 6, 12, and 24 h postoperatively were the two co-primary outcomes.

Results

Seventy-six RCTs (n = 9,665 patients) were included. Patients treated with TEAS experienced a reduction in clinical importance in cumulative analgesic (morphine equivalent) consumption (WMD: -14.60 mg, 97.5% CI: -23.60 to -5.60; p < 0.001) and a reduction in statistical importance in rest pain scores at multiple time points within the first 24 postoperative hours. The secondary outcome analysis also identified clinically significant recovery benefits to TEAS during the first 24 h after surgery. Furthermore, TEAS could effectively reduce opioid-related side effects and did not increase serious side effects.

Conclusion

This article describes current evidence about TEAS intervention on early postoperative pain and recovery. The results support the effectiveness of TEAS, but more high-quality evidence of clinical applicability is also needed.

Systematic review registration

PROSPERO (CRD42021249814).

Latest Advances in Regional Anaesthesia

Training and expertise in regional anaesthesia have increased significantly in tandem with increased interest over the past two decades. This review outlines the most recent advances in regional anaesthesia and focuses on novel areas of interest including fascial plane blocks. Pharmacological advances in the form of the prolongation of drug duration with liposomal bupivacaine are considered. Neuromodulation in the context of regional anaesthesia is outlined as a potential future direction. The growing use of regional anaesthesia outside of the theatre environment and current thinking on managing the rebound plane after regional block regression are also discussed. Recent relevant evidence is summarised, unanswered questions are outlined, and priorities for ongoing investigation are suggested.

Effect of liposomal bupivacaine for preoperative erector spinae plane block on postoperative pain following video-assisted thoracoscopic lung surgery: a protocol for a multicenter, randomized, double-blind, clinical trial

Background

There is still a controversy about the superiority of liposomal bupivacaine (LB) over traditional local anesthetics in postoperative analgesia after thoracic surgery. This study aims to determine the effect of LB versus bupivacaine hydrochloride (HCl) for preoperative ultrasound-guided erector spinae plane block (ESPB) on postoperative acute and chronic pain in patients undergoing video-assisted thoracoscopic lung surgery.

Methods

This multicenter, randomized, double-blind, controlled trial will include 272 adult patients scheduled for elective video-assisted thoracoscopic lung surgery. Patients will be randomly assigned, 1:1 and stratified by site, to the liposomal bupivacaine (LB) group or the bupivacaine (BUPI) HCl group. All patients will receive ultrasound-guided ESPB with either LB or bupivacaine HCl before surgery and patient-controlled intravenous analgesia (PCIA) as rescue analgesia after surgery. The numeric rating scale (NRS) score will be assessed after surgery. The primary outcome is the area under the curve of pain scores at rest for 0-72 h postoperatively. The secondary outcomes include the total amount of opioid rescue analgesics through 0-72 h postoperatively, time to the first press on the PCIA device as rescue analgesia, the area under the curve of pain scores on activity for 0-72 h postoperatively, NRS scores at rest and on activity at different time points during the 0-72 h postoperative period, Quality of Recovery 15 scores at 72 h after surgery, and NRS scores on activity on postsurgical day 14 and postsurgical 3 months. Adverse events after the surgery are followed up to the postsurgical day 7, including postoperative nausea and vomiting, fever, constipation, dizziness, headache, insomnia, itching, prolonged chest tube leakage, new-onset atrial fibrillation, severe ventricular arrhythmia, deep venous thrombosis, pulmonary embolism, pulmonary atelectasis, cardiac arrest, ileus, urinary retention, chylothorax, pneumothorax, and organ failure. Analyzes will be performed first according to the intention to treat principle and second with the per-protocol analysis.

Discussion

We hypothesize that LB for preoperative ultrasound-guided ESPB would be more effective than bupivacaine HCl in reducing postoperative pain in video-assisted thoracoscopic lung surgery. Our results will contribute to the optimization of postoperative analgesia regimens for patients undergoing video-assisted thoracoscopic lung surgery.Clinical trial registration:http://www.chictr.org.cn, identifier ChiCTR2300074852.

Does industry funding and study location impact findings from randomized controlled trials of spinal cord stimulation? A systematic review and meta-analysis

BACKGROUND/IMPORTANCE

Concerns have been raised that effects observed in studies of spinal cord stimulation (SCS) funded by industry have not been replicated in non-industry-funded studies and that findings may differ based on geographical location where the study was conducted.

OBJECTIVE

To investigate the impact of industry funding and geographical location on pain intensity, function, health-related quality of life and adverse events reported in randomized controlled trials (RCTs) of SCS.

EVIDENCE REVIEW

Systematic review conducted using MEDLINE, CENTRAL, EMBASE and WikiStim databases until September 2022. Parallel-group RCTs evaluating SCS for patients with neuropathic pain were included. Results of studies were combined in random-effects meta-analysis using the generic-inverse variance method. Subgroup meta-analyses were conducted according to funding source and study location. Risk of bias was assessed using Cochrane RoB 2.0 tool.

FINDINGS

Twenty-nine reports of 17 RCTs (1823 participants) were included. For the comparison of SCS with usual care, test for subgroup differences indicate no significant differences (p=0.48, moderate certainty evidence) in pain intensity score at 6 months for studies with no funding or funding not disclosed (pooled mean difference (MD) -1.96 (95% CI -3.23 to -0.69; 95% prediction interval (PI) not estimable, I2=0%, τ2=0)), industry funding (pooled MD -2.70 (95% CI -4.29 to -1.11; 95% PI -8.75 to 3.35, I2=97%, τ2=2.96) or non-industry funding (MD -3.09 (95% CI -4.47 to -1.72); 95% PI, I2 and τ2 not applicable). Studies with industry funding for the comparison of high-frequency SCS (HF-SCS) with low-frequency SCS (LF-SCS) showed statistically significant advantages for HF-SCS compared to LF-SCS while studies with no funding showed no differences between HF-SCS and LF-SCS (low certainty evidence).

CONCLUSION

All outcomes of SCS versus usual care were not significantly different between studies funded by industry and those independent from industry. Pain intensity score and change in pain intensity from baseline for comparisons of HF-SCS to LF-SCS seem to be impacted by industry funding.

Randomized Controlled Trial Comparing Liposomal to Plain Bupivacaine in the Transversus Abdominis Plane for DIEP Flap Breast Reconstruction

BACKGROUND

Pain control after autologous breast reconstruction is important for patient satisfaction and early recovery. Transversus abdominis plane (TAP) blocks are commonly used as part of an enhanced recovery after surgery (ERAS) pathway for breast reconstruction. It is uncertain whether liposomal bupivacaine used in TAP blocks offers additional advantages. This study aimed to compare the efficacy of liposomal bupivacaine versus plain bupivacaine for patients undergoing deep inferior epigastric perforator flap reconstruction.

METHODS

This double-blinded randomized controlled trial studied patients undergoing abdominally based autologous breast reconstruction between June of 2019 and August of 2020. Subjects were randomly assigned liposomal or plain bupivacaine, performed using ultrasound-guided TAP block technique. All patients were managed according to an ERAS protocol. Primary outcomes were postoperative narcotic analgesia required, measured in oral morphine equivalents from postoperative days 1 to 7. Secondary outcomes included numeric pain scale score on postoperative days 1 to 7, nonnarcotic pain medication use, time to first narcotic use, return of bowel function, and length of stay.

RESULTS

Sixty patients were enrolled: 30 received liposomal bupivacaine and 30 received plain bupivacaine. There were no significant differences in demographics, daily oral morphine equivalent narcotic use, nonnarcotic pain medication use, time to narcotic use, numeric pain scale score, time to bowel function, or length of stay.

CONCLUSION

Liposomal bupivacaine does not confer advantages over plain bupivacaine when used in TAP blocks for abdominally based microvascular breast reconstruction in patients under ERAS protocols and multimodal approaches for pain control.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, I.

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.

Trends of liposomal bupivacaine utilization in major lower extremity total joint arthroplasty in the USA: a population-based study

INTRODUCTION

Liposomal bupivacaine has been marketed for the achievement of long-acting local or regional anesthesia after major lower extremity total joint arthroplasty. However, it is comparatively expensive and controversy remains regarding its ability to decrease healthcare costs. With mounting evidence suggesting non-superiority in efficacy, compared with plain bupivacaine, we sought to investigate trends in liposomal bupivacaine use and identify changes in practice.

METHODS

We identified adult patients from the Premier Healthcare Database who underwent elective total joint arthroplasty between 2012 and 2021. Prevalence and trends of liposomal bupivacaine utilization were compared on the individual patient and hospital levels. Log-rank tests were performed to assess the influence of location, teaching status, or hospital size on time to hospital-level liposomal bupivacaine termination.

RESULTS

Among 103,165 total joint arthroplasty cases, liposomal bupivacaine use increased between 2012 and 2015 (from 0.4% to 22.8%) and decreased by approximately 1%-3% annually thereafter (15.7% in 2021). Liposomal bupivacaine was ever used in approximately 60% of hospitals. Hospital-level initiation of liposomal bupivacaine use peaked in 2014 and decreased thereafter (from 32.8% in 2013 to 4.3% in 2021), while termination rates increased (from 1.4% in 2014 to 9.9% in 2019). Non-teaching hospitals and those located in the South and West regions were more likely to retain liposomal bupivacaine longer than teaching or Midwest/Northeast hospitals, respectively (p=0.023 and p=0.014).

DISCUSSION

Liposomal bupivacaine use peaked around 2015 and has been declining thereafter on individual patient and hospital levels. How these trends correlate with health outcomes and expenditures would be a strategic target for future research.

Liposomal bupivacaine interscalene blocks demonstrate a greater proportion of total shoulder arthroplasty patients with clinically tolerable pain: a retrospective quality improvement study of 491 patients

OBJECTIVE

To evaluate the effects of liposomal bupivacaine use for interscalene blocks on postoperative analgesia in total shoulder arthroplasty patients.

METHODS

De-identified total or reverse total shoulder arthroplasty patients between 2018 and 2021 were analyzed. Patients were grouped into single shot interscalene block with liposomal bupivacaine (LB) with plain bupivacaine, other block (OB) with other local anesthetics (mepivacaine, ropivacaine, or plain bupivacaine), or no block (NB). The primary outcome was the proportion of patients with clinically tolerable pain scores (mean VAS ≤4) from 0 to 24 ​h in each group. Secondary outcomes included averaged visual analog pain scores (VAS) and opioid consumption measured in morphine milligram equivalents (MMEs) from 0 to 24 ​h. We also analyzed the proportion of patients with clinically tolerable pain, mean VAS, and opioid consumption from 0 to 72 ​h in those patients with at least a 3-day hospital length of stay.

RESULTS

A total of 491 de-identified total shoulder arthroplasty patients, 285 liposomal bupivacaine group (LB), 178 other block group (OB), and 28 no block group (NB), were analyzed. The primary outcome showed a statistically significant different proportion of patients with clinically tolerable pain from 0 to 24 ​h in the LB group (69 ​%) vs. OB group (39 ​%) vs. NB group (11 ​%) (<0.001). Secondary outcomes included statistically significant differences in VAS (LB median ​= ​3.35, OB median ​= ​4.38, NB median ​= ​5.25 (p ​< ​0.001, <0.001)) and total MME opioid consumption (LB median ​= ​40, OB median ​= ​60, NB median ​= ​88 (p ​< ​0.001, 0.001)) between groups from 0 to 24 ​h. For patients who had hospital stays of at least 3 days, a significant association was found with having achieved clinically tolerable pain 0-72 ​h and the LB group (51 ​%) vs. OB group (21 ​%) vs. NB group (11 ​%) (P ​= ​0.006). However, there was no statistical difference in mean VAS or opioid consumption between these groups.

CONCLUSION

A greater proportion of total shoulder arthroplasty patients that received liposomal bupivacaine in interscalene block have clinically tolerable pain scores from 0 to 24 ​h, lower VAS, and lower MME consumption in patients following total shoulder arthroplasty.

LEVEL OF EVIDENCE

Level III - Clinical Study.

A prospective, randomized trial of liposomal bupivacaine compared to conventional bupivacaine on pain control and postoperative opioid use in adults receiving adductor canal blocks for total knee arthroplasty

BACKGROUND

Total knee arthroplasty (TKA) is a commonly performed procedure to alleviate pain and improve functional limitations caused by end-stage joint damage. Effective management of postoperative pain following TKA is crucial to the prevention of complications and enhancement of recovery. Adductor canal blocks (ACB) with conventional bupivacaine (CB) provide adequate analgesia after TKA, but carry a risk of rebound pain following block resolution. Liposomal bupivacaine (LB) is an extended-release local anesthetic that can provide up to 72 h of pain relief. The objective of this study was to compare postoperative outcomes between ACBs using LB and CB after TKA.

METHODS

This single institution, prospective, randomized, clinical trial enrolled patients scheduled for TKA. Participants were randomized to receive ACB with either LB or CB. Pain scores up to 72 h postoperatively were assessed as the primary outcome. Opioid consumption and length of stay were evaluated as secondary outcomes.

RESULTS

A total of 80 patients were enrolled. Demographic and clinical characteristics were similar between the two groups. LB group showed significantly lower cumulative opioid use during the 72 h evaluated (P = 0.016). There were no differences in pain scores or length of stay between the groups.

CONCLUSION

The study demonstrated that LB ACBs led to significantly lower opioid consumption in the days following TKA without affecting pain scores or length of stay. This finding has important implications for improving postoperative outcomes and reducing opioid use in TKA patients. Previous studies have reported inconsistent results regarding the benefits of LB, highlighting the need for further research.

TRIAL REGISTRATION

This project was retrospectively registered with clinicaltrials.gov ( NCT05635916 ) on 2 December 2022.

Effect of Pharmacoprophylaxis on Postoperative Outcomes in Adult Elective Colorectal Surgery: A Multi-Center Retrospective Cohort Study within an Enhanced Recovery after Surgery Framework

BACKGROUND

The application of enhanced recovery after surgery principles decreases postoperative complications (POCs), length of stay (LOS), and readmissions. Pharmacoprophylaxis decreases morbidity, but the effect of specific regimens on clinical outcomes is unclear.

METHODS AND MATERIALS

Records of 476 randomly selected adult patients who underwent elective colorectal surgeries (ECRS) at 10 US hospitals were abstracted. Primary outcomes were surgical site infection (SSI), venous thromboembolism (VTE), postoperative nausea and vomiting (PONV), pain, and ileus rates. Secondary outcomes included LOS and 7- and 30-day readmission rates.

RESULTS

POC rates were SSI (3.4%), VTE (1.5%), PONV (47.9%), pain (58.1%), and ileus (16.1%). Cefazolin 2 g/metronidazole 500 mg and ertapenem 1 g were associated with the shortest LOS; cefotetan 2 g and cefoxitin 2 g with the longest LOS. No SSI occurred with ertapenem and cefotetan. More Caucasians than Blacks received oral antibiotics before intravenous antibiotics without impact. Enoxaparin 40 mg subcutaneously daily was the most common inpatient and discharge VTE prophylaxis. All in-hospital VTEs occurred with unfractionated heparin. Most received rescue rather than around-the-clock antiemetics. Scopolamine patches, spinal opioids, and IV lidocaine continuous infusion were associated with lower PONV. Transversus abdominis plane block with long-acting local anesthetics, celecoxib, non-anesthetic ketamine bolus, ketorolac IV, lidocaine IV, and pregabalin were associated with lower in-hospital pain severity rates. Gabapentinoids and alvimopan were associated with lower ileus rates. Acetaminophen, alvimopan, famotidine, and lidocaine patches were associated with shorter LOS.

CONCLUSIONS

Significant differences in pharmacotherapy regimens that may improve primary and secondary outcomes in ECRS were identified. In adult ECRS, cefotetan or ertapenem may be better regimens for preventing in-hospital SSI, while ertapenem or C/M may lead to shorter LOS. The value of OA to prevent SSI was not demonstrated. Inpatient enoxaparin, compared to UFH, may reduce VTE rates with a similar LOS. A minority of patients had a documented PONV risk assessment, and a majority used as-needed rather than around-the-clock strategies. Preoperative scopolamine patches continued postoperatively may lower PONV and PDNV severity and shorter LOS. Alvimopan may reduce ileus and shorten LOS. Anesthesia that includes TAP block, ketorolac IV, and pregabalin use may lead to reduced pain rates. Acetaminophen, alvimopan, famotidine, and lidocaine patches may shorten LOS. Given the challenges of pain management and the incidence of PONV/PDNV found in this study, additional studies should be conducted to determine optimal opioid-free anesthesia and the benefit of newer antiemetics on patient outcomes. Moreover, future research should identify latent pharmacotherapy variables that impact patient outcomes, correlate pertinent laboratory results, and examine the impact of order or care sets used for ECRS at study hospitals.

Peripheral Nerve Blocks for Cesarean Delivery Analgesia: A Narrative Review

Effective postoperative analgesia using multimodal approach improves maternal and neonatal outcomes after cesarean delivery. The use of neuraxial approach (local anesthetic and opioids) and intravenous adjunctive drugs, such as nonsteroidal anti-inflammatory drugs and acetaminophen, currently represents the standard regimen for post-cesarean delivery analgesia. Peripheral nerve blocks may be considered in patients who are unable to receive neuraxial techniques; these blocks may also be used as a rescue technique in selected patients. This review discusses the relevant anatomy, current evidence, and advantages and disadvantages of the various peripheral nerve block techniques. Further research is warranted to compare the analgesic efficacy of these techniques, especially newer blocks (e.g., quadratus lumborum blocks and erector spinae plane blocks). Moreover, future studies should determine the safety profile of these blocks (e.g., fascial plane blocks) in the obstetric population because of its increased susceptibility to local anesthetic toxicity.

Development of a prospective biliary dashboard to compare performance and surgical cost

BACKGROUND

Transparency around surgeon level data may align healthcare delivery with quality care for patients. Biliary surgery includes numerous procedures performed by both general surgeons and subspecialists alike. Cholecystectomy is a common surgical procedure and an optimal cohort to measure quality outcomes within a healthcare system.

METHODS

Data were collected for 5084 biliary operations performed by 68 surgeons in 11 surgical divisions in a health system including a tertiary academic hospital, two regional community hospitals, and two ambulatory surgery centers. A privacy protected dashboard was developed to compare surgeon performance and cost between July 2018 and June 2022. A sample cohort of patients ≥ 18 years who underwent cholecystectomy were compared by operative time, cost, and 30-day outcomes.

RESULTS

Over 4 years, 4568 cholecystectomy procedures were performed by 57 surgeons. Operations were done by 57 surgeons in four divisions and included 3846 (84.2%) laparoscopic cholecystectomies, 601 (13.2%) laparoscopic cholecystectomies with cholangiogram, and 121 (2.6%) open cholecystectomies. Patients were admitted from the emergency room in 2179 (47.7%) cases while 2389 (52.3%) cases were performed in the ambulatory setting. Individual surgeons were compared to peers for volume, intraoperative data, cost, and outcomes. Cost was lowest at ambulatory surgery centers, yet only 4.2% of elective procedures were performed at these facilities. Prepackaged kits with indocyanine green were more expensive than cholangiograms that used iodinated contrast. The rate of emergency department visits was lowest when cases were performed at ambulatory surgery centers.

CONCLUSION

Data generated from clinical dashboards can inform surgeons as to how they compare to peers regarding quality metrics such as cost, time, and complications. In turn, this may guide strategies to standardize care, optimize efficiency, provide cost savings, and improve outcomes for cholecystectomy procedures. Future application of clinical dashboards can assist surgeons and administrators to define value-based care.

Prolonged Anesthesia Effects of Locally Administered Ropivacaine via Electrospun Poly(caprolactone) Fibrous Membranes

Prolonged analgesia is important to safeguard the patient's comfort and safety during and after surgery in clinical practice. To meet the demand for prolonged analgesia, medical professionals often resort to increasing drug frequency, which may lead to poor patient compliance and serious complications due to drug overdose. Therefore, it is of great interest to develop controlled-release drug delivery systems for local anesthetics, enabling slow and controlled drug release to prolong the analgesic effect and minimize systemic toxicity. In this study, we utilized an electrospinning technique to fabricate nonwoven poly(caprolactone) (PCL) fibrous membranes loaded with Ropivacaine and performed proof-of-principle experiments on both in vitro drug release tests and in vivo animal tests, to further prolong the analgesic effect of Ropivacaine and improve postoperative local pain management and chronic pain treatment. Material characterization and in vitro drug release studies confirmed the feasibility of the Ropivacaine-loaded PCL fibrous membranes for sustained release. The drug loading content and drug loading efficiency of Ropivacaine-loaded fibrous membrane are 8.7 ± 0.3 wt% and 96 ± 3 wt%, respectively. Evaluation in an animal model demonstrated prolonged anesthesia effects along with excellent biocompatibility and stability. At 72 h, the cumulative release accounted for approximately 50% of the drug loading content. This study offers novel approaches and strategies for clinical postoperative pain management and chronic pain treatment, while providing new insights and directions for the design of local anesthetic controlled-release delivery systems.

Pain relief after major ankle and hindfoot surgery with repetitive peripheral nerve blocks: A feasibility study

BACKGROUND

Major ankle and hindfoot surgery (e.g., ankle, triple and subtalar arthrodesis) typically causes severe postoperative pain, especially the first two postoperative days. Current modalities of postoperative analgesic treatment often include continuous peripheral nerve blocks of the saphenous and sciatic nerves via catheters in order to extend the duration of pain- and opioid-free nerve blockade to 48 h. Unfortunately, the 48 h-efficacy of continuous infusion via a catheter is reduced by a high displacement rate. We hypothesised that one-time repetition of the single injection peripheral nerve blocks would provide effective analgesia with a low opioid consumption the first 48 postoperative hours.

METHODS

Eleven subjects preoperatively received a popliteal sciatic and a saphenous single injection nerve block with a protracted local anaesthetic mixture. Surgery was performed under general anaesthesia. The one-time repetition of the single injection nerve block was carried out approximately 24 h after the primary nerve block. The main outcomes were pain and cumulative opioid consumption during the first 48 postoperative hours.

RESULTS

Nine of the 11 (82%) patients had effective analgesia without opioids during the first 48 postoperative hours. Two patients each required a single dose of 7.5 mg of oral morphine equivalents after 43 h.

CONCLUSION

One-time repetition of single injection saphenous and sciatic nerve blocks consistently provided effective analgesia practically without opioids for 48 h after major elective ankle and hindfoot surgery.

Free academic discourse and the law: the case of liposomal bupivacaine

Liposomal bupivacaine has been the topic of intense academic debate over the past years culminating in an industry-initiated libel lawsuit against the American Society of Anesthesiologists and various other defendants. In this Daring Discourse, we first aim to provide a general overview of main themes in the ongoing controversy: (1) between-study heterogeneity, (2) the high number of negative high-quality reviews and meta-analyses, (3) publication bias in the context of an active role of industry and (4) difference between statistical and clinical significance. We then discuss the contents of the lawsuit, its potential implications and what the recent resolution of this lawsuit means for the future of research and the academic discourse on liposomal bupivacaine.

Achieving Long-Acting Local Analgesia Using an Intelligent Hydrogel Encapsulated with Drug and pH Regulator

Local anesthetics are important for the treatment of postoperative pain. Since a single injection of the solution of a drug such as bupivacaine (BUP) works only for a few hours, it is much required to develop a long-term injectable formulation that maintains its efficacy for more than 1 day. Herein, an intelligent copolymer hydrogel loaded with BUP microcrystals was invented. The biodegradable block copolymer was synthesized by us and composed of a central hydrophilic poly(ethylene glycol) (PEG) block and two hydrophobic poly(lactide-co-glycolide) (PLGA) blocks. The aqueous system of the amphiphilic copolymer underwent a sol-gel transition between room temperature and body temperature and, thus, physically gelled after injection. Considering the decrease of solubility of BUP with the increase of pH and the internal acidic environment due to the hydrolysis of PLGA, calcium carbonate (CaCO3) powder was introduced as a pH regulator. Then, the internal pH was found to be nearly neutral and many BUP microcrystals were dispersed in the gel network. In this way, BUP had achieved a sustained release out of the thermogel. The maximum possible effect (MPE) in a rat sciatic nerve blockade model was used to describe the sensory blockade effect. In vivo analgesic effects evaluated with a hot plate experiment of rats demonstrated that the thermogel encapsulated with BUP microcrystal and CaCO3 powder significantly prolonged analgesia up to 44 h, the duration time with respect to 50% MPE. The intramuscularly injected implant exhibited biocompatibility in histological analyses. Besides, the untreated leg of the rats was not influenced by the treated leg, indicating no obvious systematic anesthesia of this hydrogel formulation. Such an intelligent and composite formulation represents a potential strategy for long-acting analgesia therapy.

Regional anaesthesia for ambulatory surgery

Regional anaesthesia (RA) has an important and ever-expanding role in ambulatory surgery. Specific practices vary depending on the preferences and resources of the anaesthesia team and hospital setting. It is used for various purposes, including as primary anaesthetic technique for surgery but also as postoperative analgesic modality. The limited duration of action of currently available local anaesthetics limits their application in postoperative pain control and enhanced recovery. The search for the holy grail of regional anaesthetics continues. Current evidence suggests that a peripheral nerve block performed with long-acting local anaesthetics in combination with intravenous or perineural dexamethasone gives the longest and most optimal sensory block. In this review, we outline some possible blocks for ambulatory surgery and additives to perform RA. Moreover, we give an update on local anaesthesia drugs and adjuvants, paediatric RA in ambulatory care and discuss the impact of RA by COVID-19.

The postoperative analgesic efficacy of liposomal bupivacaine versus long-acting local anaesthetics for peripheral nerve and field blocks: A systematic review and meta-analysis, with trial sequential analysis

BACKGROUND

Liposomal bupivacaine is claimed by the manufacturer to provide analgesia for up to 72 h postoperatively.

OBJECTIVES

To compare the postoperative analgesic efficacy of liposomal bupivacaine versus long-acting local anaesthetics for peripheral nerve or field blocks.

DESIGN

A systematic review and meta-analysis with trial sequential analysis.

DATA SOURCES

MEDLINE, Embase and Web of Science, among others, up to June 2022.

ELIGIBILITY CRITERIA

We retrieved randomised controlled trials comparing liposomal bupivacaine versus bupivacaine, levobupivacaine or ropivacaine for peripheral nerve and field blocks after all types of surgery. Our primary endpoint was rest pain score (analogue scale 0 to 10) at 24 h. Secondary endpoints included rest pain score at 48 and 72 h, and morphine consumption at 24, 48 and 72 h.

RESULTS

Twenty-seven trials including 2122 patients were identified. Rest pain scores at 24 h were significantly reduced by liposomal bupivacaine with a mean difference (95% CI) of -0.9 (-1.4 to -0.4), I2  = 87%, P  < 0.001. This reduction in pain scores persisted at 48 h and 72 h with mean differences (95% CI) of -0.7 (-1.1 to -0.3), I2  = 82%, P  = 0.001 and -0.7 (-1.1 to -0.3), I2  = 80%, P  < 0.001, respectively. There were no differences in interval morphine consumption at 24 h ( P  = 0.15), 48 h ( P  = 0.15) and 72 h ( P  = 0.07). The quality of evidence was moderate.

CONCLUSIONS

There is moderate level evidence that liposomal bupivacaine reduces rest pain scores by 0.9 out of 10 units, when compared with long-acting local anaesthetics at 24 hours after surgery, and by 0.7 up to 72 hours after surgery.

Adjunctive dexamethasone palmitate use for intercostal nerve block after video-assisted thoracoscopic surgery: A prospective, randomized control trial

Objectives

The efficacy of dexamethasone palmitate in extending durations of local anesthetic blocks is uncertain. In a randomized, double-blind study of patients undergoing video-assisted thoracoscopic surgery, we tested whether intravenous or perineural dexamethasone palmitate caused prolonged analgesia after intercostal nerve block.

Methods

A total of 90 patients subjected to video-assisted thoracoscopic surgery between May and December 2022 were randomly assigned to one of three intercostal nerve blocks study arms (n = 30 each), requiring the addition of 0.5% ropivacaine (23 ml) as follows: controls (C group), 2 ml saline; IV-DXP group, 2 ml saline + 2 ml (8 mg) intravenous dexamethasone palmitate; and PN-DXP group, 2 ml (8 mg) perineural dexamethasone palmitate. Time to first postoperative remedial analgesia served as primary outcome measure. Secondary endpoints included postoperative opioid consumption, pain scores by Visual Analog Scale, analgesia satisfaction, and related adverse effects.

Results

Compared with controls or the IV-DXP group, time to first postoperative remedial analgesia was longer and postoperative opioid consumption for rescue analgesia was lower in the PN-DXP group (p < 0.01). Similarly, the Visual Analog Scale scores in patients at 8, 12, 18, and 24 h postoperatively were lower in the PN-DXP group than in controls and the IV-DXP group (p < 0.01). Patient satisfaction was statistically lower in the PN-DXP group, compared with either the control or IV-DXP group (p < 0.05). Clinically, the three groups did not differ significantly in occurrences of adverse effects during the 48-h postoperative monitoring period (p > 0.05).

Conclusions

Perineural dexamethasone palmitate is a promising adjunct to ropivacaine intercostal nerve block by prolonging analgesia with almost no related adverse effects.

Emerging Anesthetic Nanomedicines: Current State and Challenges

Anesthetics, which include both local and general varieties, are a unique class of drugs widely utilized in clinical surgery to alleviate pain and promote relaxation in patients. Although numerous anesthetics and their traditional formulations are available in the market, only a select few exhibit excellent anesthetic properties that meet clinical requirements. The main challenges are the potential toxic and adverse effects of anesthetics, as well as the presence of the blood-brain barrier (BBB), which makes it difficult for most general anesthetics to effectively penetrate to the brain. Loading anesthetics onto nanocarriers as anesthetic nanomedicines might address these challenges and improve anesthesia effectiveness, reduce toxic and adverse effects, while significantly enhance the efficiency of general anesthetics passing through the BBB. Consequently, anesthetic nanomedicines play a crucial role in the field of anesthesia. Despite their significance, research on anesthetic nanomedicines is still in its infancy, especially when compared to other types of nanomedicines in terms of depth and breadth. Although local anesthetic nanomedicines have received considerable attention and essentially meet clinical needs, there are few reported instances of nanomedicines for general anesthetics. Given the extensive usage of anesthetics and the many of them need for improved performance, emerging anesthetic nanomedicines face both unparalleled opportunities and considerable challenges in terms of theory and technology. Thus, a comprehensive summary with systematic analyses of anesthetic nanomedicines is urgently required. This review provides a comprehensive summary of the classification, properties, and research status of anesthetic nanomedicines, along with an exploration of their opportunities and challenges. In addition, future research directions and development prospects are discussed. It is hoped that researchers from diverse disciplines will collaborate to study anesthetic nanomedicines and develop them as a valuable anesthetic dosage form for clinical surgery.

Regional Anesthesia in Upper-Limb Surgery

BACKGROUND

Local and regional anesthesia is associated with numerous clinical and institutional advantages relative to general anesthesia. As anesthesiologists and surgeons increasingly integrate local and regional anesthesia into their clinical practice, an understanding of the principles, evolution, and trends underpinning modern anesthetic techniques continues to be relevant.

METHODS

A review of the literature in databases Medline, PubMed, and EMBASE identified recent developments, ongoing trends, and historical milestones in upper-limb regional anesthesia.

RESULTS

Advances in regional anesthetic techniques in the last century have led to reduced postoperative pain, improved safety, and improved outcomes in upper-limb surgery. The development of ultrasound-guided techniques, as well as pharmacological advances in local anesthetic drugs and adjuncts, has further advanced the role of regional anesthesia. Wide-awake local anesthesia with no tourniquet has allowed certain procedures to be performed on select patients in outpatient and low-resource settings.

CONCLUSIONS

This review provides an overview of local and regional anesthesia in the upper-limb from its historical origins to its contemporary applications in upper-limb surgery, particularly during the COVID-19 pandemic.

Periarticular Injection Versus Peripheral Nerve Blockade in Bilateral Total Hip Arthroplasty

Pain control after total hip arthroplasty is associated with patient satisfaction, early discharge, and improved surgical outcomes. Two commonly utilized opioid-reducing analgesic modalities are periarticular injection (PAI) by surgeons and motor-sparing peripheral nerve block (PNB) by anesthesiologists. We present a case contrasting PAI and PNB in a single patient undergoing bilateral total hip arthroplasty. For the left hip, the patient received preoperative transmuscular quadratus lumborum, femoral nerve, and lateral femoral cutaneous nerve blocks using a combination of low-concentration local anesthetic and glucocorticoids. For the right hip, the patient received an intraoperative PAI with liposomal bupivacaine. The patient's pain scores and recovery were evaluated for three months postoperatively. The patient's pain scores on postoperative day (POD) zero to five were consistently lower in the left hip than in the right hip. For this patient undergoing bilateral hip replacement, preoperative PNBs were superior to PAI for postoperative pain control.

Liposomal Bupivacaine in Dentistry and Oral and Maxillofacial Surgery. A Review of Human and Veterinary Literature

This article reviews the human and veterinary literature regarding liposome encapsulated bupivacaine use in dentistry and oral and maxillofacial surgery. The purpose of this review is to present available information on this local anesthetic in a manner that will allow veterinary dentists and oral and maxillofacial surgeons to use evidence-based information when considering incorporating liposomal bupivacaine into their practice. The twelve human clinical studies and three veterinary reports that met the literature search criteria do not support the use of liposomal bupivacaine in veterinary dentistry and oral and maxillofacial surgery.

Peripheral Regional Anesthesia Using Local Anesthetics: Old Wine in New Bottles?

During the past decade, numerous efforts were undertaken aiming at prolonging the analgesic effect of regional anesthesia. With the development of extended-release formulations and enhanced selectivity for nociceptive sensory neurons, a very promising contribution to the development of pain medications has been achieved. At present, liposomal bupivacaine is the most popular, non-opioid, controlled drug delivery system, but its duration of action, which is still controversially discussed, and its expensiveness have decreased initial enthusiasm. Continuous techniques can be seen as an elegant alternative for providing a prolonged duration of analgesia, but for logistic or anatomical reasons, they are not always the best choice. Therefore, focus has been directed towards the perineural and/or intravenous addition of old and established substances. As for perineural application, most of these so-called 'adjuvants' are used outside their indication, and their pharmacological efficacy is often not or only poorly understood. This review aims to summarize the recent developments for prolonging the duration of regional anesthesia. It will also discuss the potential harmful interactions and side effects of frequently used analgesic mixtures.

Measures to prolong duration of sensory block after regional anaesthesia

PURPOSE OF REVIEW

The duration of single-injection regional anaesthesia is limited due to the inherent pharmacological properties of local anaesthetics. The ideal duration of a regional anaesthesia block lasting for the first 24 h postoperatively can be stated, while a residual analgesic effect thereafter is desirable.The aim of this review is to present current options to prolong the duration of action of single-injection peripheral regional anaesthesia in the ambulatory setting. Secondly, this review outlines and discusses the latest evidence regarding the clinical use of adjuvants and sustained-release local anaesthetics.

RECENT FINDINGS

Extended-release formulations of local anaesthetics such as liposomal bupivacaine have been developed to prolong regional anaesthesia up to 96 h. Recent studies, however, show that the actual effects remain far behind expectations and that the efficacy is only marginally better than bupivacaine hydrochloride.Adjuvants to local anaesthetics have been studied extensively with heterogenous results. Dexamethasone and alpha-2 agonists range among the most effective measures to prolong single-injection nerve blocks.Continuous nerve blocks and catheter techniques may prolong regional anaesthesia very effectively, but are less cost-effective regarding block procedure, postoperative care and handling logistical issues especially in ambulatory surgery.

SUMMARY

In conclusion, adjuvants are the recommended measure to prolong regional anaesthesia where needed. With good evidence supporting it, dexamethasone is the most effective adjuvant, followed by dexmedetomidine. Both have few side effects and a favourable safety profile. However, a preferable duration of analgesia lasting for the first 24 h postoperatively is still not reliably achievable.

Postoperative Analgesia in Enhanced Recovery After Surgery Protocols: Trends and Updates

Multimodal analgesia is an effective strategy to decrease opioid use after surgery and has been a mainstay of the surgical contribution to combat the opioid epidemic. Postoperative multimodal analgesia in Enhanced Recovery After Surgery (ERAS) continues to evolve as different adjuncts are added and removed based on the most up to date literature. This review examines recent trends in ERAS analgesia and what current evidence and research supports as well as those adjuncts that may not be as beneficial as once thought.

Recent updates on interscalene brachial plexus block for shoulder surgery

Interscalene brachial plexus block (ISBPB) provides optimal analgesia for shoulder surgery. However, several limitations still exist, including the short duration of analgesia, rebound pain, a high incidence of unilateral diaphragmatic paresis, and potential risk of nerve damage, prompting the search for alternative techniques. Many alternatives to ISBPB have been studied to alleviate these concerns, and clinicians should choose an appropriate option based on the patient's condition. In this mini-review, we aimed to present recent updates on ISBPB while discussing our clinical experiences in shoulder surgery.

Sternotomy Wound Infiltration With Liposomal Versus Plain Bupivacaine for Postoperative Analgesia After Elective Cardiac Surgery

OBJECTIVES

Poor pain control after cardiac surgery can be associated with postoperative complications, longer recovery, and development of chronic pain. The authors hypothesized that adding liposomal bupivacaine (LB) to plain bupivacaine (PB) will provide better and long-lasting analgesia when used for wound infiltration in median sternotomy.

STUDY DESIGN

Prospective, randomized, and double-blinded clinical trial.

SETTING

Single institution, tertiary care university hospital.

PARTICIPANTS

Adult patients who underwent elective cardiac surgery through median sternotomy.

INTERVENTIONS

A single surgeon performed wound infiltration of LB plus PB or PB into the sternotomy wound, chest, and mediastinal tube sites.

MEASUREMENTS AND MAIN RESULTS

Patients were followed up for 72 hours for pain scores, opioid consumption, and adverse events. Sixty patients completed the study for analysis (LB group [n = 29], PB group [n = 31]). Patient characteristics, procedural variables, and pain scores measured at specific intervals from 4 hours until 72 hours postoperatively did not reveal any significant differences between the groups. Mixed-model regression showed that the trend of mean pain scores at movement in the LB group was significantly (p = 0.01) lower compared with the PB group. Opioid consumption over 72 hours was not significantly different between the 2 groups (oral morphine equivalents; median [interquartile range], 139 [73, 212] mg in LB v 105 [54, 188] mg in PB, p = 0.29). Recovery characteristics and adverse events were comparable.

CONCLUSIONS

LB added to PB for sternotomy wound infiltration during elective cardiac surgery did not significantly improve the quality of postoperative analgesia.

Dexamethasone Does Not Provide Additional Clinical Analgesia Effect to Local Wound Infiltration: A Comprehensive Systematic Review and Meta-Analysis

Objective: Although the use of dexamethasone as an adjunct agent is associated with alleviating pain and prolonging analgesic duration in local wound infiltration (LWI), efficacy and safety of dexamethasone infiltration have not been fully explored. The study sought to quantify the pooled effects of dexamethasone infiltration on postoperative pain, analgesic consumption, and side effects through a review of randomized controlled trials (RCTs). Approach: RCTs comparing dexamethasone + LWI with LWI alone were retrieved from seven electronic databases. Co-primary outcomes were rest pain scores and cumulative morphine equivalent consumption within 24 h postoperatively. The study followed PRISMA, AMSTAR, and the Cochrane Collaboration. Results: Eight trials comprising 609 patients were included in the final analysis. Results indicated that dexamethasone infiltration effects were only statistical but not clinically significant at individual time points of rest pain and patient satisfaction scores. Notably, the effect of dexamethasone infiltration therapy on other pain-related parameters, including cumulative morphine consumption (mean difference, -9.05 mg; 95% CI: -22.47 to 4.37), was not significantly different compared with the control group. Analysis showed no significant differences in safety indicators between the two groups. The overall quality of evidence was high to very low. Innovation: Although statistically significant effects of dexamethasone infiltration were observed for some outcomes of postoperative wound pain, the overall benefits were below the expected minimal clinically important difference. Conclusions: In summary, the current evidence does not support routine clinical use of dexamethasone in LWI. However, further studies should explore the clinical value of preemptive analgesia and safety of a combination of dexamethasone with ropivacaine for LWI.

The effect of liposomal bupivacaine for surgical wound infiltration: A meta‐analysis of randomised controlled trials

Liposomal bupivacaine (LB) has consistently been considered a potential analgesic for surgical wound infiltration. However, the evidence of its analgesic effectiveness remains unclear. In this meta-analysis, we attempted to identify the potential clinical role of LB wound infiltration in different surgical procedures. Randomised controlled trials (RCTs) comparing LB with non-liposomal local anaesthetics and placebos were retrieved from six electronic databases. The primary outcome was cumulative morphine equivalent consumption within 24, 48, and 72 hours after surgery. Approximately 2659 patients from 22 studies were included in the meta-analysis. Compared to the control, LB-wound infiltration did not reduce the postoperative morphine consumption at 24 hours (weighted mean difference [WMD], -0.60 mg; 97.5% confidence interval [CI], -2.78 to 1.59 mg; P = 0.54), 48 hours (WMD, -1.00 mg; 97.5% CI, -3.23 to 1.24; P = 0.32) or 72 hours (WMD, 0.50 mg; 97.5% CI, -0.67 to 1.67; P = 0.33). Similarly, secondary outcome analysis did not reveal any additional benefits of LB in any other pain-related outcomes. LB was not associated with any adverse effects. Overall, LB does not appear to improve the postoperative analgesic, rehabilitation, or safety outcomes. Current evidence does not support the routine use of LB for wound infiltration following surgical procedures.

Comparing bupivacaine alone to liposomal bupivacaine plus bupivacaine in interscalene blocks for total shoulder arthroplasty: a randomized, non-inferiority trial

Introduction

Interscalene brachial plexus blocks are a commonly performed procedure to reduce pain following total shoulder arthroplasty. Liposomal bupivacaine has been purported to prolong the duration of brachial plexus blocks for up to 72 hours; however, there has been controversy surrounding the analgesic benefits of this drug. Our hypothesis was that an interscalene block performed with bupivacaine alone would be non-inferior to a combination of liposomal bupivacaine and bupivacaine with respect to opioid consumption following total shoulder arthroplasty.

Methods

Subjects presenting for primary total shoulder arthroplasty were randomized in a 1:1 ratio to an ultrasound-guided, single-injection interscalene block with either a combination of liposomal bupivacaine and bupivacaine (LB group) or bupivacaine without additive (Bupi group). The primary outcome of this study was 72-hour postoperative cumulative opioid consumption (in oral morphine equivalents) with a non-inferiority margin of 22.5 mg. Secondary outcomes included pain scores, patient satisfaction with analgesia and patient reported duration of sensory block.

Results

Seventy-six subjects, 38 from the Bupi group and 38 from the LB group, completed the study. Analysis of the primary outcome showed a 72-hour cumulative geometric mean oral morphine equivalent consumption difference of 11.9 mg (95% CI −6.9 to 30.8) between groups (calculated on the log scale). This difference constitutes approximately 1.5 tablets of oxycodone over 3 days. No secondary outcomes showed meaningful differences between groups.

Discussion

Interscalene brachial plexus blocks performed with bupivacaine alone did not demonstrate non-inferiority compared to a mixture of liposomal bupivacaine plus bupivacaine with regards to 72-hour cumulative opioid consumption following total shoulder arthroplasty. However, the difference between groups did not appear to be clinically meaningful.

Outcomes After Orthopedic Trauma Surgery - What is the Role of the Anesthesia Choice?

The body of literature concerning the influence of anesthetic type on many perioperative outcomes has grown considerably in recent years. Most studies have suggested that particularly in orthopedic patients, regional anesthesia may be associated with improved perioperative outcomes. Orthopedic trauma presents itself as a field that might benefit from increased utilization of regional techniques with the goal to improve outcomes. This narrative review concludes that, indeed, regional anesthesia seems to provide benefits for morbidity, pain control, and improved return to function in hip fracture, rib fracture, and isolated extremity fracture patients.