Bupivacaine extended-release liposome injection for prolonged postsurgical analgesia in patients undergoing hemorrhoidectomy: a multicenter, randomized, double-blind, placebo-controlled trial

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

Extended Release of Bupivacaine from Temperature-Responsive PNDJ Hydrogels Improves Postoperative Weight-Bearing in Rabbits Following Knee Surgery

Effective treatment of postoperative pain lasting for multiple days without opioids is an important clinical need. We previously reported analgesia lasting up to 96 h in a porcine soft tissue model of postoperative pain using SBG004, an extended-release formulation of bupivacaine based on the temperature-responsive polymer poly(N-isopropylacrylamide-co-dimethylbutyrolactone acrylamide-co-Jeffamine M-1000 acrylamide) [PNDJ]. Orthopaedic surgical sites such as the knee can involve complex sensory innervation which presents a distinct challenge to local anesthetic delivery. The purpose of this work was to evaluate the pharmacokinetics and efficacy of SBG004 in an orthopaedic surgical model in comparison to currently available local anesthetics. Pharmacokinetics following periarticular (PA) or intraarticular (IA) injection of SBG004 were compared against liposomal bupivacaine (Lip-Bupi) PA in New Zealand White rabbits (all doses 14.5 mg/kg). Analgesic efficacy of SBG004 (IA, PA, or IA + PA), three active comparators, and saline was evaluated following knee surgery in New Zealand White rabbits. Analgesia was assessed via weight-bearing on the operated limb during spontaneous large steps in video recordings. Systemic bupivacaine exposure lasted at least 7 days for SBG004 PA, 4 days for SBG004 IA, and 2 days for Lip-Bupi PA. In the analgesia study, weight-bearing in all active groups except SBG004 IA was more frequent versus saline through 8 h postoperatively (p < 0.05). Only SBG004 IA + PA resulted in a higher proportion of weight-bearing rabbits at 24 h versus saline (6/7 versus 2/10, p = 0.015). Analysis of pooled data from 24-72 h showed significantly greater frequency of weight-bearing in rabbits receiving SBG004 IA + PA (71%) versus saline (37%), ropivacaine cocktail (41%), and Lip-Bupi PA (36%). The results indicate that the release profile from SBG004 PA or IA coincides reasonably with the time course of postoperative pain, and SBG004 may produce longer duration of analgesia than local anesthetics currently used in knee surgery, including during the period of 24-72 h recognized as a target for extended-release local anesthetics.

Evaluating the efficacy and safety of perianal injection of liposomal ropivacaine HR18034 for postoperative analgesia following hemorrhoidectomy: A multicenter, randomized, double-blind, controlled phase II clinical trial

STUDY OBJECTIVE

HR18034, composed of the ropivacaine encapsulated in multi-lamellar, concentric circular structure liposomes as the major component and a small amount of free ropivacaine, has performed well in animal experiments and phase I clinical trials. This trial was to investigate the efficacy, safety, pharmacokinetic profile and the minimum effective dose of HR18034 for postoperative analgesia after hemorrhoidectomy compared with ropivacaine.

DESIGN

A multicenter, randomized, double-blind trial.

SETTING

19 medical centers in China.

PATIENTS

85 patients undergoing hemorrhoidectomy between October 2022 to November 2022.

INTERVENTIONS

Patients were randomly divided into HR 18034 190 mg group, 285 mg group, 380 mg group and ropivacaine 75 mg group, receiving single local anesthetic perianal injection for postoperative analgesia.

MEASUREMENTS

The primary outcome was the area under the resting state NRS score -time curve within 72 h after injection. The second outcomes included the proportion of patients without pain, the proportion of patients not requiring rescue analgesia, cumulative morphine consumption for rescue analgesia, etc. Safety was evaluated by adverse events incidence and plasma ropivacaine concentrations were measured to explore the pharmacokinetic characteristics of HR18034.

MAIN RESULTS

The areas under the NRS score (at rest and moving states)-time curve were significantly lower in HR 18034 380 mg group than ropivacaine 75 mg at 24 h, 48 h, and 72 h after administration. However, this superiority was not observed in HR18034 190 mg group and 285 mg group. There was no difference in cumulative morphine consumption for rescue analgesia between HR 18034 groups and ropivacaine group.

CONCLUSIONS

HR 18034 380 mg showed superior analgesic efficacy and equivalent safety compared to ropivacaine 75 mg after hemorrhoidectomy, thus preliminarily determined as minimum effective dose.

Management of Hemorrhoids and Anal Fissures

Hemorrhoids and anal fissures are two of the most common benign anorectal diseases. Despite their high prevalence, diagnostic accuracy of benign anorectal disease is suboptimal at 70% for surgeons, especially for hemorrhoidal diseases. Once the diagnosis is correctly made, numerous medical and surgical treatment options are available, each with different rates of success and complications. In this article, the authors review each step of patient management, with emphasis on evidence-based treatment options for hemorrhoids and anal fissures. The article discusses the pathophysiology, diagnosis, medical management, and procedures for hemorrhoids followed by a detailed overview on the management of anal fissures.

Local anesthetic delivery systems for the management of postoperative pain

Postoperative pain (POP) is a major clinical challenge. Local anesthetics (LAs), including amide-type LAs, ester-type LAs, and other potential ion-channel blockers, are emerging as drugs for POP management because of their effectiveness and affordability. However, LAs typically exhibit short durations of action and prolonging the duration by increasing their dosage or concentration may increase the risk of motor block or systemic local anesthetic toxicity. In addition, techniques using LAs, such as intrathecal infusion, require professional operation and are prone to catheter displacement, dislodgement, infection, and nerve damage. With the development of materials science and nanotechnology, various LAs delivery systems have been developed to compensate for these disadvantages. Numerous delivery systems have been designed to continuously release a safe dose in a single administration to ensure minimal systemic toxicity and prolong pain relief. LAs delivery systems can also be designed to control the duration and intensity of analgesia according to changes in the external trigger conditions, achieve on-demand analgesia, and significantly improve pain relief and patient satisfaction. In this review, we summarize POP pathways, animal models and methods for POP testing, and highlight LAs delivery systems for POP management. STATEMENT OF SIGNIFICANCE: Postoperative pain (POP) is a major clinical challenge. Local anesthetics (LAs) are emerging as drugs for POP management because of their effectiveness and affordability. However, they exhibit short durations and toxicity. Various LAs delivery systems have been developed to compensate for these disadvantages. They have been designed to continuously release a safe dose in a single administration to ensure minimal toxicity and prolong pain relief. LAs delivery systems can also be designed to control the duration and intensity of analgesia to achieve on-demand analgesia, and significantly improve pain relief and patient satisfaction. In this paper, we summarize POP pathways, animal models, and methods for POP testing and highlight LAs delivery systems for POP management.

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.

The effect of bupivacaine on analgesia and safety in patients undergoing hemorrhoidectomy: a meta-analysis

Aim: There is no meta-analysis reporting the analgesic effect and safety of bupivacaine in patients undergoing hemorrhoidectomy. This meta-analysis provides quantitative evidence of the effect of bupivacaine in hemorrhoidectomy. Methods: Studies were searched from PubMed, Embase, the Cochrane Library, and the Web of Science. Standardized mean difference (SMD), weighted mean difference (WMD), and odds ratios (ORs) with 95% confidence interval (CI) were used as effect indicators. Heterogeneity was assessed using the I 2 index, and sensitivity analysis was conducted to determine the effect of the single study on the pooled results. Results: A total of 18 studies were included in this meta-analysis. The pain level at 48 h was lower in the bupivacaine-combined other drug group than in the other drug group (WMD = -0.65, 95% CI: 1.18 to -0.11, and I2 = 37.50%). Compared to the bupivacaine group, the odds of pruritus (OR = 12.11, 95% CI: 1.49-98.59, and I2 = 0%) and urinary retention (OR = 4.45, 95% CI: 1.12-17.70, and I2 = 0%) were higher, and the pain level at 6 h (WMD = -2.13, 95% CI: 3.22 to -1.04, and I2 = 64.30%), at 12 h (WMD = -1.55, 95% CI: 2.19 to -0.90, and I2 = 56.10%), and at 24 h (SMD = -1.15, 95% CI: 1.89 to -0.42, and I2 = 82.5%) were lower in the bupivacaine-combined other drug group. Conclusion: Bupivacaine-combined other drugs had a good analgesic effect after hemorrhoidectomy, but the adverse reactions should be considered.

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.

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.

Liposomal bupivacaine versus conventional anesthetic or placebo for hemorrhoidectomy: a systematic review and meta-analysis

BACKGROUND

Liposome bupivacaine (LB) is a long-acting anesthetic to enhance postoperative analgesia. Studies evaluating the efficacy of the LB against an active comparator (bupivacaine or placebo) on acute postoperative pain control in hemorrhoidectomy procedures are few and heterogeneous. Therefore, we performed a systematic review and meta-analysis comparing LB's analgesic efficacy and side effects to conventional/placebo anesthetic in hemorrhoidectomy patients.

METHODS

We performed a systematic review and meta-analysis of randomised controlled trials investigating the use of LB after haemorrhoidectomy. We searched the literature published from the time of inception of the datasets to August 19, 2022. The electronic databases included English publications in Ovid MEDLINE In-Process & Other Non-Indexed Citations, Ovid MEDLINE, Ovid EMBASE, and Scopus.

RESULTS

A total of 338 patients who underwent a hemorrhoidectomy procedure enrolled in three randomized clinical trials were included. The overall mean age was 45.84 years (SD ± 11.43), and there was a male predominance (53.55% male). In total 194 patients (52.2%) received LB and 144 (47.8%) received either bupivacaine or placebo. Pain scores at 72 h in the LB (199, 266, and 300 mg) were significantly lower than in the bupivacaine HCl group (p = 0.002). Compared to the bupivacaine/placebo group, the time to first use of opioids in the LB group was significantly longer at LB 199 mg (11 h vs. 9 h), LB 266 mg (19 h vs. 9 h), and LB 300 mg (19 h vs. 8 h) (p < 0.05). Moreover, compared to the bupivacaine/epinephrine group, it was significantly lower in the LB 266 mg group (3.7 vs. 10.2 mg) and at LB 300 mg (13 vs. 33 mg) (p < 0.05). Finally, regarding adverse effects, the conventional anesthetic/placebo group reported more pain in bowel movement than LB groups (OR 2.60, 95% CI 1.31-5.16).

CONCLUSIONS

Comparing LB to conventional anesthetic/placebo anesthetic for hemorrhoidectomy, we found a statistically significant reduction in pain through 72 h, decreased opioid requirements, and delayed time to first opioid use. Moreover, the conventional anesthetic/placebo group reported more pain in bowel movement than LB groups.

Liposomal and Nonliposomal Bupivacaine for Mohs Surgery: A Systematic Review

BACKGROUND

Lidocaine is the most commonly used local anesthetic for Mohs micrographic surgery (MMS), but given its limited half-life, postoperative pain remains a significant concern for patients. Bupivacaine is used in various surgical subspecialty procedures and has demonstrated improved pain control compared with lidocaine. However, its role in MMS is insufficiently explored.

OBJECTIVE

To systematically review the current literature for reports on use of bupivacaine, traditional nonliposomal and newer liposomal formulations, for MMS.

METHODS

A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. The MEDLINE, PubMed, and EMBASE databases were queried for articles presenting original data on the use of bupivacaine for MMS.

RESULTS

Of 483 potentially relevant articles, 3 studies met final inclusion criteria, capturing a total of 253 patients involved in primary investigations comparing bupivacaine to traditional local anesthesia for MMS. Bupivacaine was well-tolerated and associated with comparable or modestly reduced intraoperative and postoperative pain and opioid use.

CONCLUSION

Bupivacaine may have a role in prolonging intraoperative anesthesia, reducing acute postoperative pain, and reducing postoperative opioid use after MMS. However, large, prospective studies are needed to solidify the generalizability and clinical utility of these findings.

Application of Advanced Technologies-Nanotechnology, Genomics Technology, and 3D Printing Technology-In Precision Anesthesia: A Comprehensive Narrative Review

There has been increasing interest and rapid developments in precision medicine, which is a new medical concept and model based on individualized medicine with the joint application of genomics, bioinformatics engineering, and big data science. By applying numerous emerging medical frontier technologies, precision medicine could allow individualized and precise treatment for specific diseases and patients. This article reviews the application and progress of advanced technologies in the anesthesiology field, in which nanotechnology and genomics can provide more personalized anesthesia protocols, while 3D printing can yield more patient-friendly anesthesia supplies and technical training materials to improve the accuracy and efficiency of decision-making in anesthesiology. The objective of this manuscript is to analyze the recent scientific evidence on the application of nanotechnology in anesthesiology. It specifically focuses on nanomedicine, precision medicine, and clinical anesthesia. In addition, it also includes genomics and 3D printing. By studying the current research and advancements in these advanced technologies, this review aims to provide a deeper understanding of the potential impact of these advanced technologies on improving anesthesia techniques, personalized pain management, and advancing precision medicine in the field of anesthesia.

Recent Research Advances in Nano-Based Drug Delivery Systems for Local Anesthetics

From a clinical perspective, local anesthetics have rather widespread application in regional blockade for surgery, postoperative analgesia, acute/chronic pain control, and even cancer treatments. However, a number of disadvantages are associated with traditional local anesthetic agents as well as routine drug delivery administration ways, such as neurotoxicity, short half-time, and non-sustained release, thereby limiting their application in clinical practice. Successful characterization of drug delivery systems (DDSs) for individual local anesthetic agents can support to achieve more efficient drug release and prolonged duration of action with reduced systemic toxicity. Different types of DDSs involving various carriers have been examined, including micromaterials, nanomaterials, and cyclodextrin. Among them, nanotechnology-based delivery approaches have significantly developed in the last decade due to the low systemic toxicity and the greater efficacy of non-conventional local anesthetics. Multiple nanosized materials, including polymeric, lipid (solid lipid nanoparticles, nanostructured lipid carriers, and nanoemulsions), metallic, inorganic non-metallic, and hybrid nanoparticles, offer a safe, localized, and long-acting solution for pain management and tumor therapy. This review provides a brief synopsis of different nano-based DDSs for local anesthetics with variable sizes and structural morphology, such as nanocapsules and nanospheres. Recent original research utilizing nanotechnology-based delivery systems is particularly discussed, and the progress and strengths of these DDSs are highlighted. A specific focus of this review is the comparison of various nano-based DDSs for local anesthetics, which can offer additional indications for their further improvement. All in all, nano-based DDSs with unique advantages provide a novel direction for the development of safer and more effective local anesthetic formulations.

Characterization of exparel bupivacaine multivesicular liposomes

Exparel is a bupivacaine multivesicular liposomes (MVLs) formulation developed based on the DepoFoam technology. The complex composition and the unique structure of MVLs pose challenges to the development and assessment of generic versions. In the present work, we developed a panel of analytical methods to characterize Exparel with respect to particle size, drug and lipid content, residual solvents, and pH. In addition, an accelerated in vitro drug release assay was developed using a rotator-facilitated, sample-and-separate experimental setup. The proposed method could achieve over 80% of bupivacaine release within 24 h, which could potentially be used for formulation comparison and quality control purposes. The batch-to-batch variability of Exparel was examined by the established analytical methods. Four different batches of Exparel showed good batch-to-batch consistency in drug content, particle size, pH, and in vitro drug release kinetics. However, slight variation in lipid contents were observed.

Bilateral transversus abdominis plane and rectus sheath blocks with liposomal bupivacaine for patients undergoing robotic prostatectomy

As robotic prostatectomy surgery becomes more prevalent, it is important to identify any regional techniques to optimize patient's recovery. We evaluated the effectiveness of bilateral transversus abdominis plane (TAP) and rectus sheath (RS) blocks with liposomal bupivacaine. We hypothesized that these blocks would reduce perioperative opioid use and pain scores. A retrospective cohort of patients from May 2018 and May 2021 at a single large VA hospital were studied. We compared those not receiving a nerve block against those receiving the TAP and RS as part of an Enhanced Recovery After Surgery (ERAS) pathway starting in May 2019. The primary outcome was post-operative opioid use. Secondary outcomes were post-operative pain scores and hospital length of stay. One hundred and thirty-four patients were included in the final analysis. Eighty-one patients did not receive a block and fifty-three patients did receive a block. No difference existed between the groups in regard to median oral morphine equivalents (mg) used in PACU or any post-operative day. No difference existed in median opioid usage (mg) or pain scores between the two groups on any post-operative day. There was no difference in temporal association of median pain scores or narcotic usage between the two groups. Bilateral TAP and RS with liposomal bupivacaine did not significantly decrease post-operative opioid use, improve pain scores, or decrease hospital length of stay for patients undergoing robotic prostatectomy. Further studies need to be done to evaluate the effect of these blocks with liposomal bupivacaine.

The use of liposomal bupivacaine in fracture surgery: a review

Historically, opioids have played a major role in the treatment of postoperative pain in orthopedic surgery. A multitude of adverse events have been associated with opioid use and alternative approaches to pain relief are being investigated, with particular focus on multimodal pain management regimens. Liposomal bupivacaine (EXPAREL) is a component of some multimodal regimens. This formulation of bupivacaine encapsulates the local anesthetic into a multivesicular liposome to theoretically deliver a consistent amount of drug for up to 72 hours. Although the use of liposomal bupivacaine has been studied in many areas of orthopedics, there is little evidence evaluating its use in patients with fractures. This systematic review of the available data identified a total of eight studies evaluating the use of liposomal bupivacaine in patients with fractures. Overall, these studies demonstrated mixed results. Three studies found no difference in postoperative pain scores on postoperative days 1-4, while two studies found significantly lower pain scores on the day of surgery. Three of the studies evaluated the quantity of narcotic consumption postoperatively and failed to find a significant difference between control groups and groups treated with liposomal bupivacaine. Further, significant variability in comparison groups and study designs made interpretation of the available data difficult. Given this lack of clear evidence, there is a need for prospective, randomized clinical trials focused on fully evaluating the use of liposomal bupivacaine in fracture patients. At present, clinicians should maintain a healthy skepticism and rely on their own interpretation of the available data before widely implementing the use of liposomal bupivacaine.

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.

Evaluation of liposomal bupivacaine infiltration at reconstructive skin graft donor sites in adolescent and young adult burn patients: A retrospective analysis

BACKGROUND

Postoperative pain at skin graft donor sites is frequently undertreated in burn patients, which can impair reconstructive outcomes and result in harmful psychological consequences. We find a critical need to explore and promote non-opioid, multimodal analgesics. Donor site infiltration of the local anesthetic liposomal bupivacaine in adolescent and young adult burn patients has not been previously investigated. Therefore, the goal of this study was to evaluate intraoperative liposomal bupivacaine infiltration for postoperative donor site pain control in adolescent and young adult burn patients undergoing reconstructive skin graft procedures.

METHODS

This retrospective analysis included patients aged 14-25 years, who underwent at least two reconstructive skin graft procedures, one that received donor site infiltration of the standard treatment (bupivacaine hydrochloride) and one that received donor site infiltration of liposomal bupivacaine. The final sample included 30 patients with a total of 44 liposomal bupivacaine cases and 53 standard treatment cases analyzed.

RESULTS

In the authors' five-year experience, the use of liposomal bupivacaine compared to standard treatment was associated with statistically significant decreases in 0-4 h postoperative pain scores (mean 1.4/10 versus 2.3/10, p = 0.04) and 0-24 h postoperative pain scores (mean 1.7/10 versus 2.4/10, p = 0.02). Neither analgesic was associated with adverse events. Differences in length of stay and inpatient postoperative opioid usage were not regarded as significant.

CONCLUSION

In this retrospective analysis, the authors report the first results that suggest intraoperative liposomal bupivacaine donor site infiltration may be associated with statistically improved patient outcomes in adolescent and young adult burn patients. However, the reported differences are most likely not clinically significant, establishing the necessity for further evaluation of using liposomal bupivacaine in this unique patient population.

Ultrasound-Triggered on Demand Lidocaine Release Relieves Postoperative Pain

Safe and non-invasive on-demand relief is a crucial and effective treatment for postoperative pain because it considers variable timing and intensity of anesthetics. Ultrasound modulation is a promising technique for this treatment because it allows convenient timed and non-invasive controlled drug release. Here, we created an ultrasound-triggered lidocaine (Lido) release platform using an amino acid hydrogel functioning as three-dimensional (3D) scaffold material (Lido-PPIX@ER hydrogel). It allows control of the timing, intensity and duration of lidocaine (Lido) to relieve postoperative pain. The hydrogel releases Lido due to the elevated reactive oxygen species (ROS) levels generated by PPIX under ultrasound triggering. The Lido-PPIX@ER hydrogel under individualized ultrasound triggering released lidocaine and provided effective analgesia for more than 72 h. The withdrawal threshold was higher than that in the control group at all time points measured. The hydrogel showed repeatable and adjustable ultrasound-triggered nerve blocks in vivo, the duration of which depended on the extent and intensity of insonation. On histopathology, no systemic effect or tissue reaction was observed in the ultrasound-triggered Lido-PPIX@ER hydrogel-treated group. The Lido-PPIX@ER hydrogel with individualized (highly variable) ultrasound triggering is a convenient and effective method that offers timed and spatiotemporally controlled Lido release to manage postoperative pain. This article presents the delivery system for a new effective strategy to reduce pain, remotely control pain, and offer timed and spatiotemporally controlled release of Lido to manage postoperative pain.

Recent advances in pain management based on nanoparticle technologies

BACKGROUND

Pain is a vital sense that indicates the risk of injury at a particular body part. Successful control of pain is the principal aspect in medical treatment. In recent years, the advances of nanotechnology in pain management have been remarkable. In this review, we focus on literature and published data that reveal various applications of nanotechnology in acute and chronic pain management.

METHODS

The presented content is based on information collected through pain management publications (227 articles up to April 2021) provided by Web of Science, PubMed, Scopus and Google Scholar services.

RESULTS

A comprehensive study of the articles revealed that nanotechnology-based drug delivery has provided acceptable results in pain control, limiting the side effects and increasing the efficacy of analgesic drugs. Besides the ability of nanotechnology to deliver drugs, sophisticated nanosystems have been designed to enhance imaging and diagnostics, which help in rapid diagnosis of diseases and have a significant impact on controlling pain. Furthermore, with the development of various tools, nanotechnology can accurately measure pain and use these measurements to display the efficiency of different interventions.

CONCLUSIONS

Nanotechnology has started a new era in the pain management and many promising results have been achieved in this regard. Nevertheless, there is still no substantial and adequate act of nanotechnology in this field. Therefore, efforts should be directed to broad investigations.

Strategies to Reduce Post-Hemorrhoidectomy Pain: A Systematic Review

Background and Objectives: Excisional hemorrhoidectomy is considered as a mainstay operation for high-grade hemorrhoids and complicated hemorrhoids. However, postoperative pain remains a challenging problem after hemorrhoidectomy. This systematic review aims to identify pharmacological and non-pharmacological interventions for reducing post-hemorrhoidectomy pain. Materials and Methods: The databases of Ovid MEDLINE, PubMed and EMBASE were systematically searched for randomized controlled trails (published in English language with full-text from 1981 to 30 September 2021) to include comparative studies examining post-hemorrhoidectomy pain as their primary outcomes between an intervention and another intervention (or a sham or placebo). Results: Some 157 studies were included in this review with additional information from 15 meta-analyses. Fundamentally, strategies to reduce post-hemorrhoidectomy pain were categorized into four groups: anesthetic methods, surgical techniques, intraoperative adjuncts, and postoperative interventions. In brief, local anesthesia-alone or combined with intravenous sedation was the most effective anesthetic method for excisional hemorrhoidectomy. Regarding surgical techniques, closed (Ferguson) hemorrhoidectomy performed with a vascular sealing device or an ultrasonic scalpel was recommended. Lateral internal anal sphincterotomy may be performed as a surgical adjunct to reduce post-hemorrhoidectomy pain, although it increased risks of anal incontinence. Chemical sphincterotomy (botulinum toxin, topical calcium channel blockers, and topical glyceryl trinitrate) was also efficacious in reducing postoperative pain. So were other topical agents such as anesthetic cream, 10% metronidazole ointment, and 10% sucralfate ointment. Postoperative administration of oral metronidazole, flavonoids, and laxatives was associated with a significant reduction in post-hemorrhoidectomy pain. Conclusions: This systematic review comprehensively covers evidence-based strategies to reduce pain after excisional hemorrhoidectomy. Areas for future research on this topic are also addressed at the end of this article.

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.

Intercostal liposomal bupivacaine injection for rib fractures: A prospective randomized controlled trial

BACKGROUND

Blunt chest wall injury accounts for 15% of trauma admissions. Previous studies have shown that the number of rib fractures predicts inpatient opioid requirements, raising concerns for pharmacologic consequences, including hypotension, delirium, and opioid dependence. We hypothesized that intercostal injection of liposomal bupivacaine would reduce analgesia needs and improve spirometry metrics in trauma patients with rib fractures.

METHODS

A prospective, double-blinded, randomized placebo-control study was conducted at a Level I trauma center as a Food and Drug Administration investigational new drug study. Enrollment criteria included patients 18 years or older admitted to the intensive care unit with blunt chest wall trauma who could not achieve greater than 50% goal inspiratory capacity. Patients were randomized to liposomal bupivacaine or saline injections in up to six intercostal spaces. Primary outcome was to examine pain scores and breakthrough pain medications for 96-hour duration. The secondary endpoint was to evaluate the effects of analgesia on pulmonary physiology.

RESULTS

One hundred patients were enrolled, 50 per cohort, with similar demographics (Injury Severity Score, 17.9 bupivacaine 17.6 control) and comorbidities. Enrolled patients had a mean age of 60.5 years, and 47% were female. Rib fracture number, distribution, and targets for injection were similar between groups. While both groups displayed a decrease in opioid use over time, there was no change in mean daily pain scores. The bupivacaine group achieved higher incentive spirometry volumes over Days 1 and 2 (1095 mL, 1063 mL bupivacaine vs. 900 mL, 866 mL control). Hospital and intensive care unit lengths of stay were similar and there were no differences in postinjection pneumonia, use of epidural catheters or adverse events bet ween groups.

CONCLUSION

While intercostal liposomal bupivacaine injection is a safe method for rib fracture-related analgesia, it was not effective in reducing pain scores, opioid requirements, or hospital length of stay. Bupivacaine injection transiently improved incentive spirometry volumes, but without a reduction in the development of pneumonia.

LEVEL OF EVIDENCE

Therapeutic/care management, Level II.

Efficacy of Liposomal Bupivacaine versus Ropivacaine in Adductor Canal Block for Total Knee Arthroplasty

Adductor canal block (ACB) is advantageous for postoperative analgesia in total knee arthroplasty (TKA) because it results in minimal motor block. Liposomal bupivacaine (LB) is Food and Drug Administration-approved extended-release formulation of bupivacaine for interscalene peripheral nerve blocks. Its use is increasing in the TKA setting, mainly as a local infiltration agent. We compared the efficacy of ACB using LB versus ropivacaine in TKA. Two cohorts of patients were retrospectively analyzed at a single institution receiving ropivacaine and LB ACB for TKA. Duration of LB ACB, time to first opioid use postrecovery room, amount of opioid use postrecovery room, length of stay (LOS), and average and highest pain scores were collected. A total of 91 and 142 TKA patients received ropivacaine and LB for ACB, respectively. At 8 hours postrecovery room, more patients in the LB group required no opioids compared with the ropivacaine group (p = 0.026). Mean opioid consumption was lower in the LB group than in the ropivacaine group at 8 and 24 hours postrecovery room, although statistical significance was only observed at 8 hours (p = 0.022). The highest pain score for patients in the two groups was not statistically different. The average pain score for patients with a 2-day LOS was higher in the LB group, but average pain scores were similar for patients with 1- and 3-day LOS. Median LOS for the LB and ropivacaine groups was 1 and 2 days, respectively (p < 0.0001). Significantly lower opioid use at 8 hours postrecovery room was seen in the LB group compared with the ropivacaine group. There was no difference in opioid use at 24 and 48 hours. There was also no advantage with LB ACB in decreasing pain scores. However, the LB ACB group demonstrated a significantly shorter LOS compared with the ropivacaine ACB group.

Transversus abdominis plane block with liposomal bupivacaine versus continuous epidural analgesia for major abdominal surgery: The EXPLANE randomized trial

OBJECTIVE

Compare transversus abdominis plane (TAP) blocks with liposomal bupivacaine were to epidural analgesia for pain at rest and opioid consumption in patients recovering from abdominal surgery.

BACKGROUND

ERAS pathways suggest TAP blocks in preference to epidural analgesia for abdominal surgery. However, the relative efficacies of TAP blocks and epidural analgesia remains unknown.

METHODS

Patients having major abdominal surgery were enrolled at six sites and randomly assigned 1:1 to thoracic epidural analgesia or bilateral/4-quadrant TAP blocks with liposomal bupivacaine. Intravenous opioids were used as needed. Non-inferiority margins were a priori set at 1 point on an 11-point pain numeric rating scale for pain at rest and at a 25% increase in postoperative opioid consumption.

RESULTS

Enrollment was stopped per protocol at 3rd interim analysis after crossing an a priori futility boundary. 498 patients were analyzed (255 had TAP blocks and 243 had epidurals). Pain scores at rest in patients assigned to TAP blocks were significantly non-inferior to those given epidurals, with an estimated difference of 0.09 points (CI: -0.12, 0.30; noninferiority P < 0.001). Opioid consumption during the initial 3 postoperative days in TAP patients was not non-inferior to epidurals, with an estimated ratio of geometric means of 1.37 (CI: 1.05, 1.79; non-inferiority P = 0.754). However, the absolute difference was only 21 mg morphine equivalents over the 3 days. Patients with epidurals were more likely to experience mean arterial pressures <65 mmHg than those given TAP blocks: 48% versus 31%, P = 0.006.

CONCLUSION

Pain scores at rest during the initial three days after major abdominal surgery were similar. Patients assigned to TAP blocks required more opioid then epidural patients but had less hypotension. Clinicians should reconsider epidural analgesia in patients at risk from hypotension.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02996227.

New peripheral nerve blocks and local anesthetics

PURPOSE OF REVIEW

To describe current developed regional blocks, their indications and clinical use. Furthermore, describe new local anesthetics recently introduced and the new agents in pipeline.

RECENT FINDINGS

There are multiple new blocks recently developed with the introduction of ultrasound to regional anesthesia and studies demonstrate effect in different surgical procedures. However, majority of the studies do not compare with gold standard and are relatively small to change clinical practice. Some of these blocks are: erector spinae plane block, infiltration between the popliteal artery and capsule of the posterior knee, pectoral nerve blocks, quadratus lumborum and transversus abdominis plane block. New local anesthetics and adjuvants have been developed in recent years. However, the studies with even with the oldest one introduced Exparel is currently questioned, large future studies are needed to determine efficacy and safety profile and compared with conventional local anesthetics.

SUMMARY

New regional block techniques and new local anesthetics have been introduced recently. However, the efficacy/safety and comparison to conventional techniques and local anesthetics are still needed. Future studies must focus on prolonging analgesia with least invasive regional technique and compare new local anesthetics with current ones.

Anesthesia in Total Shoulder Arthroplasty: A Systematic Review and Meta-Analysis

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For shoulder arthroplasty, regional anesthesia is safer when compared with general anesthesia. There is insufficient evidence to demonstrate the superiority of regional anesthesia with respect to pulmonary complications and hospital length of stay.

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Infiltration of the shoulder with local anesthetics offers no additional benefits compared with single-shot or continuous brachial plexus blocks for shoulder arthroplasty.

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There is high-quality evidence (Level I) demonstrating lower pain scores and lower perioperative opioid requirements after a continuous peripheral nerve block compared with a single-shot nerve block. However, catheter dislodgment and logistical issues with catheter insertion are impediments to the widespread usage of a continuous nerve block with an indwelling catheter.

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Liposomal bupivacaine is comparable with non-liposomal local anesthetic agents with respect to pain relief, the opioid-sparing effect, and adverse effects in the first 48 hours after total shoulder arthroplasty.

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Perioperative dexamethasone administration improves postoperative pain control, decreases perioperative opioid requirements, and reduces postoperative nausea.

Preoperative pudendal block with liposomal and plain bupivacaine reduces pain associated with posterior colporrhaphy: a double-blinded, randomized controlled trial

BACKGROUND

Pelvic reconstructive surgery may cause significant postoperative pain, especially with posterior colporrhaphy, contributing to a longer hospital stay and increased pain medication utilization. Regional blocks are being increasingly utilized in gynecologic surgery to improve postoperative pain and decrease opioid usage, yet preoperative pudendal blocks have not been used routinely during posterior colporrhaphy.

OBJECTIVE

This study aimed to compare the effect of preoperative regional pudendal nerve block using a combination of 1.3% liposomal and 0.25% plain bupivacaine vs 0.25% plain bupivacaine alone on vaginal pain after posterior colporrhaphy on postoperative days 1, 2, and 3. We hypothesized that there would be a reduction in vaginal pain scores for the study group vs the control group over the first 72 hours.

STUDY DESIGN

This was a double-blinded, randomized controlled trial that included patients undergoing a posterior colporrhaphy, either independently or in conjunction with other vaginal or abdominal reconstructive procedures. Patients were block randomized to receive 20 mL of either a combination of 1.3% liposomal and 0.25% plain bupivacaine (study) or 20 mL of 0.25% plain bupivacaine (control) in a regional pudendal block before the start of surgery. Double blinding was achieved by covering four 5-mL syringes containing the randomized local anesthetic. After induction of anesthesia, a pudendal nerve block was performed per standard technique (5 mL superiorly and 5 mL inferiorly each ischial spine) using a pudendal kit. The primary outcome was to evaluate postoperative vaginal pain using a visual analog scale on postoperative days 1, 2, and 3. Secondary outcomes included total analgesic medication usage through postoperative day 3, postoperative voiding and defecatory dysfunction, and impact of vaginal pain on quality of life factors.

RESULTS

A total of 120 patients were enrolled (60 in each group). There were no significant differences in demographic data, including baseline vaginal pain (P=.88). Postoperative vaginal pain scores were significantly lower in the combined liposomal and bupivacaine group at all time points vs the plain bupivacaine group. Median pain scores for the study and control groups, respectively, were 0 (0-2) and 2 (0-4) for postoperative day 1 (P=.03), 2 (1-4) and 3 (2-5) for postoperative day 2 (P=.05), and 2 (1-4) and 3 (2-5) for postoperative day 3 (P=.02). Vaginal pain scores increased from postoperative day 1 to postoperative days 2 and 3 in both groups. There was a significant decrease in ibuprofen (P=.01) and acetaminophen (P=.03) usage in the study group; however, there was no difference between groups in total opioid consumption through postoperative day 3 (P=.82). There was no difference in successful voiding trials (study 72%, control 82%, P=.30), return of bowel function (P>.99), or quality of life factors (sleep, stress, mood, and activity).

CONCLUSION

Preoperative regional pudendal block with a combination of liposomal and plain bupivacaine provided more effective vaginal pain control than plain bupivacaine alone for reconstructive surgery that included posterior colporrhaphy. Given the statistically significant decrease in vaginal pain in the study group, this block may be considered as a potential adjunct for multimodal pain reduction in this patient population.

Liposomal Bupivacaine Versus Standard Bupivacaine in the Adductor Canal for Total Knee Arthroplasty: A Randomized, Controlled Trial

Peripheral nerve blocks are commonly used in total knee arthroplasty (TKA). Liposomal bupivacaine is an extended-release anesthetic medication that maintains efficacy upwards of 72 hours. This study compared single-shot liposomal bupivacaine (LB) with the standard single-shot bupivacaine (SB) in a preoperative adductor canal block in TKA patients. A double-blind randomized, controlled trial at a single institution was performed in patients undergoing TKA. A standard preoperative single-shot adductor canal nerve injection was performed in 31 patients using 266 mg of liposomal bupivacaine (20 mL), whereas 32 patients received a standard formulation of 0.5% bupivacaine hydrogen chloride (20 mL). The primary outcome measure was postoperative gait velocity. Secondary outcomes included knee range of motion, pain scores, patient satisfaction, knee extension strength, opioid consumption, length of stay, and adverse events. There were no differences in baseline measures between groups. Improved pain ratings with activity (P=.009) were noted on postoperative day 1 with LB (mean, 4.4; SD, 2.0) compared with SB (mean, 5.9; SD, 2.6). Fewer opioids were used with LB compared with SB on postoperative day 1 (mean, 51.2 vs 66.1; P=.020) and on postoperative day 2 (mean, 39.5 vs 54.8; P=.016). No statistically significant differences in gait velocity, knee range of motion, knee extension strength, or patient satisfaction occurred. Peripheral nerve blockade with a single-shot adductor canal injection demonstrated improved pain scores with activity and diminished postoperative narcotic use when using LB compared with SB in TKA patients. There may be early postoperative advantages with LB as a single-shot injection in adductor canal blockade for patients undergoing TKA. [Orthopedics. 2021;44(4):249-255.].

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.

Evaluation of bupivacaine liposome injectable suspension efficacy in single-use vials over five days of multiple use

OBJECTIVE

To test the anesthetic effect of a bupivacaine liposome injectable suspension (BLIS), used in a multiple-dose manner for up to 5 consecutive days.

STUDY DESIGN

Prospective, randomized, experimental study.

ANIMALS

A total of 30 male and female Sprague-Dawley rats (Rattus norvegicus), aged 97 (75-130) days and weighing 337.2 (219.6-465.9) g, mean (range).

METHODS

Rats were assigned to one of five BLIS vial groups, in which drug was administered from a newly opened vial or 1, 2, 3 and 4 days after the vial was opened. The vials were refrigerated between uses. A 14 gauge needle attached to an injection plug was used to puncture each vial once and was not removed; BLIS was withdrawn from the injection plug in a multiple-dose fashion. A dose rate of 0.4 mL kg^-1 was administered subcutaneously into the left pelvic limb paw. Antinociception was evaluated using a paw pressure test on both injected and uninjected paws before (time 0, baseline) and 1, 24, 48 and 72 hours after injection.

RESULTS

Age of BLIS vial had no significant effect on anesthetic efficacy (p = 0.97). Across all groups, paw withdrawal latency averaged 5.23 ± 0.24 seconds at baseline (before BLIS injection), increased to 16.45 ± 0.65 seconds at 1 hour after BLIS injection, declined to 7.50 ± 0.76 seconds at 24 hours after BLIS injection, and further declined thereafter (p < 0.001). There was no significant change in paw withdrawal latency in the uninjected paw over time.

CONCLUSIONS AND CLINICAL RELEVANCE

BLIS single-use vials retained efficacy when used up to 5 days in a multiple-dose fashion. Because anesthetic effects declined substantially after 24 hours, multimodal pain management remains important for providing analgesia care.

Pain management after laparoscopic appendectomy: Comparative effectiveness of innovative pre-emptive analgesia using liposomal bupivacaine

BACKGROUND

Laparoscopic appendectomy is standard of care for appendicitis in the US. Pain control that limits opioids is an important area of research given the opioid epidemic. This study examined post-appendectomy inpatient opioid use and pain scores following intraoperative use of liposomal bupivacaine (LB) versus non-liposomal bupivacaine.

METHODS

This was a retrospective cohort study of 155 adults who underwent laparoscopic appendectomy for acute appendicitis. Patients were divided into four cohorts based on the analgesia administered: (i) bupivacaine hydrochloride (BH)± epinephrine; (ii) undiluted LB; (iii) LB diluted with normal saline; and (iv) LB diluted with BH.

RESULTS

Baseline demographic/clinical attributes, intra-operative findings, and post-operative pain scores were equivalent across cohorts. Post-operative pre-discharge opioid use was higher in the BH vs. LB cohorts (mean 60.4 vs. 46.0, 35.5, and 30.4 morphine milligram equivalents, respectively; p < 0.001).

CONCLUSIONS

Pre-emptive analgesia with LB during laparoscopic appendectomy can reduce inpatient opioid use without significantly increasing post-operative pain scores.

Liposomal bupivacaine addition versus standard bupivacaine alone for colorectal surgery: a randomized controlled trial

Aim: This study evaluated use of liposomal bupivacaine (LB) versus standard bupivacaine (SB) alone in quadratus lumborum (QL) blocks for laparoscopic colorectal surgery. Materials & methods: In this prospective, randomized controlled trial, patients received QL1 blocks with either LB (40 ml 0.125% SB plus 20 ml of LB) or SB (60 ml of 0.25% SB) with 30 ml per side. Opioid usage, pain scores, side effects and other medications were recorded. Results: For 78 patients (38 LB; 40 SB), all parameters were similar between groups, except that the LB group had a higher 48 h need for metoclopramide. Conclusion: LB provided no analgesic benefit over SB alone for QL blocks. Clinical Trials registration number: NCT03702621.

Efficacy of liposomal bupivacaine in spine surgery: a systematic review

BACKGROUND CONTEXT

Spine surgery with posterior approaches may involve extensive manipulation of native structures, resulting in significant postoperative pain. Liposomal bupivacaine (LB) is an injectable analgesic that has demonstrated efficacy in decreasing postoperative pain and opioid requirements in patients across multiple surgical subspecialties.

PURPOSE

To consolidate and analyze the findings of retrospective cohort-matched studies and prospective randomized controlled trials investigating the use of LB in spine surgery.

STUDY DESIGN

A systematic review.

STUDY SAMPLE

Retrospective cohort-matched studies and randomized controlled trials (RCTs) investigating the efficacy of injected LB in spinal surgery compared with a control/no treatment group.

METHODS

MEDLINE, Cochrane controlled trials register, and Google Scholar were searched to identify all studies that examined the effect of LB use on outcomes in spine surgery. Our search identified 10 articles that independently evaluated the effect of LB on reduction of postoperative opioid use, pain scores, hospital length of stay, cost, and incidence of adverse effects. The principles of GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) were applied to assess the quality of evidence from each study.

RESULTS

Ten studies were analyzed (1,112 total patients). LB was associated with significantly lower millimolar morphine equivalents (MME) of postoperative opioids, especially in opiate-tolerant patients, visual analog scale (VAS) scores, area under the curve (AUC) of cumulative pain scores, numeric pain scale scores, and hospital length of stay (LOS), with comparable or lower odds of adverse effects relative to controls.

CONCLUSIONS

Low-quality evidence suggests that liposomal bupivacaine may safely decrease postoperative opioid requirements, pain scores, and length of stay in patients undergoing spine surgery, whereas moderate-quality evidence does not support its use at this time. Therefore, additional standardized well-powered prospective studies are necessary to more clearly assess the efficacy of LB in spine surgery.

Does Local Administration of Liposomal Bupivacaine Reduce Pain and Narcotic Consumption in Adult Spinal Deformity Surgery?

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To determine if local administration of liposomal bupivacaine (LB) reduces postoperative pain scores and narcotic use in spinal deformity patients.

METHODS

Adult patients undergoing elective spinal fusion (7 or more levels) for scoliosis or kyphosis were selected for inclusion. Patients received either periincisional injections of combined liposomal and standard bupivacaine (n = 90, group L) or standard bupivacaine only (n = 69, group C). Perioperative pain scores (VAS [visual analogue scale]), opioid use, length of stay, functional outcome (ODI [Oswestry Disability Index]), and perioperative complications were recorded. No external funding was received for this study.

RESULTS

A total of 159 patients met inclusion criteria (mean age was 54.2 years of age). No significant baseline demographic differences were noted between the 2 groups. Group L experienced slight improvements in pain control on postoperative day (POD) 1 (P = .02). No difference in pain scores were otherwise noted. Group L transitioned off of intravenous (IV) narcotics faster with 52.6% less IV use by POD3 (P = .03). No differences in total narcotic consumption, perioperative complications, lengths of stay, and functional outcome scores were otherwise noted between the 2 cohorts.

CONCLUSIONS

The use of LB in adult spinal deformity surgery does not appear to provide clinically important improvements in postoperative pain at the manufacturer's recommended dosage. Furthermore, while patients receiving LB may transition more quickly off of IV narcotics, this does not appear to translate into an overall decrease in narcotic consumption, hasten return of bowel function, or decrease hospital lengths of stay. Future prospective randomized control trials are warranted. The use of varying dosages of LB may also help further clarify the true efficacy of LB in the setting of spinal deformity surgery.

Nanotherapeutic-directed approaches to analgesia

The ongoing opioid crisis highlighted the need for non-steroidal anti-inflammatory drugs (NSAIDs), nonaddictive analgesics against pain, fever, and inflammation. However, NSAIDs may cause gastrointestinal and cardiovascular adverse effects. To avoid systemic toxicity and deliver drugs to diseased tissues, nanotechnology methods of NSAID encapsulation have been reported and some have reached clinical development. Currently, 57 micro- and nanodrugs are approved by the US FDA. Already approved nanoanalgesics have revealed superior efficacy or reduced toxicity compared with placebo or lower doses of systemically administered active comparators. In this review, the evidence for approval of the marketed nanodrugs will be discussed, with a focus on therapies for pain and inflammation. Nanomedicine remains an attractive field for the development of targeted analgesics.

The Efficacy of Liposomal Bupivacaine for Opioid and Pain Reduction: A Systematic Review of Randomized Clinical Trials

Background The opioid crisis has prompted surgeons to search for alternative postoperative methods of analgesia. Liposomal bupivacaine is a long-acting local anesthetic formulation used for pain, potentially reducing opioid use. Evaluation of liposomal bupivacaine as a viable alternative for pain management is needed. The objective was to assess the efficacy of randomized clinical trials (RCTs) of liposomal bupivacaine in postoperative pain management and opioid consumption. Material and Methods The authors extracted RCTs comparing liposomal bupivacaine versus placebo or active comparators for postoperative pain or opioid reduction from PubMED/MEDLINE, Cochrane Library, and ClinicalTrials.gov. Exclusion criteria included nonhuman studies, non-RCTs, pooled studies, and inability to access full text. The following variables were abstracted: surgical specialty, number of subjects, pain and opioid outcomes, and authors' financial conflicts of interest. Results We identified 77 published RCTs, of which 63 studies with a total of 6770 subjects met inclusion criteria. Liposomal bupivacaine did not demonstrate significant pain relief compared to placebo or active agents in 74.58% of RCTs. Of the studies evaluating narcotic use, liposomal bupivacaine did not show a reduction in opioid consumption in 85.71% of RCTs. Liposomal bupivacaine, when compared to standard bupivacaine or another active agent, yielded no reduction in opioid use in 83.33% and 100.00% of studies, respectively. Clinical trials with a financial conflict of interest relating to the manufacturer of liposomal bupivacaine were significantly more likely to show pain relief (OR: 14.31 [95% CI, 2.8, 73.10], P = 0.0001) and decreased opioid consumption (OR: 12.35 [95% CI 1.40, 109.07], P = 0.0237). Of the 265 unpublished RCTs on ClinicalTrials.gov, 47.54% were withdrawn, terminated, suspended, or completed without study results available. Conclusions The efficacy of liposomal bupivacaine for providing superior postoperative pain control relative to placebo or another active agent is not supported by a majority of RCTs. Underreporting of trial results and bias due to underlying financial relationships amongst authors are two major concerns that should be considered when evaluating the available evidence.

Evidence-based review of methods used to reduce pain after excisional hemorrhoidectomy

Background Excisional hemorrhoidectomy is one of the most commonly performed anorectal procedures. Despite the satisfactory outcomes of excisional hemorrhoidectomy, the pain perceived by the patients following the procedure can be a distressing sequel. This review aimed to search the current literature for the existing evidence on how to avoid or minimize the severity of post-hemorrhoidectomy pain.

Methods An organized literature search was performed using electronic databases including PubMed/Medline and Google Scholar service for the articles that evaluated different methods for pain relief after excisional hemorrhoidectomy. Then, the studies were summarized in a narrative way illustrating the hypothesis and the outcomes of each study. The methods devised to reduce pain after excisional hemorrhoidectomy were classified into three main categories: technical tips; systemic and topical agents; and surgical methods. The efficacy of each method was highlighted along the level of evidence supporting it.

Results Stronger evidence (level Ia) supported LigaSure hemorrhoidectomy and the use of glyceryl trinitrate ointment to be associated with significant pain relief after excisional hemorrhoidectomy whereas the remaining methods were supported by lower level of evidence (level Ib).

Conclusion The use of LigaSure in performing excisional hemorrhoidectomy and the application of topical glyceryl trinitrate ointment contributed to remarkable relief of postoperative pain after excisional hemorrhoidectomy according to the highest level of evidence. Perhaps a multimodality strategy that combines systemic and topical agents can be the optimal method for control of pain after excisional hemorrhoidectomy, yet further prospective trials are required to draw such conclusion.

Effectiveness of Standard Local Anesthetic Bupivacaine and Liposomal Bupivacaine for Postoperative Pain Control in Patients Undergoing Truncal Incisions: A Randomized Clinical Trial

IMPORTANCE

Liposomal bupivacaine for pain relief is purported to last 3 days compared with 8 hours with standard bupivacaine. However, its effectiveness is unknown in truncal incisions for cardiothoracic or vascular operations.

OBJECTIVE

To compare the effectiveness of single-administration standard bupivacaine vs liposomal bupivacaine in patients undergoing truncal incisions.

DESIGN, SETTING, AND PARTICIPANTS

This randomized clinical trial enrolled patients undergoing sternotomy, thoracotomy, minithoracotomy, and laparotomy from a single cardiovascular surgery department in an academic medical center between November 2012 and June 2018. The study was powered to detect a Cohen effect size of 0.35 with a power of greater than 80%. Data analysis was performed from July to December 2018.

INTERVENTION

Patients were randomized to standard bupivacaine or liposomal bupivacaine.

MAIN OUTCOMES AND MEASURES

Pain was assessed over 3 postoperative days by the Numeric Rating Scale (NRS). Adjunctive opioids were converted to morphine equivalents units (MEU). NRS scores were compared using Wilcoxon rank-sum (3-day area under the curve) and 2-way nonparametric mixed models (daily scale score) to assess time-by-group interaction. Secondary outcomes included cumulative opioid consumption.

RESULTS

A total of 280 patients were analyzed, with 140 in each group (single-administration standard bupivacaine vs liposomal bupivacaine). Mean (SD) age was 60.2 (14.4) years, and 101 of 280 patients (36%) were women. Irrespective of treatment assignment, pain decreased by a mean of approximately 1 point per day over 3 days (β = -0.87; SE = 0.11; mixed model regression P < .001). Incision type was associated with pain with patients undergoing thoracotomy (including minithoracotomy) reporting highest median (interquartile range [IQR]) pain scores on postoperative days 1 (liposomal vs standard bupivacaine, 6 [4-8] vs 5 [3-7]; P = .049, Wilcoxon rank-sum) and 2 (liposomal vs standard bupivacaine, 5 [4-7] vs 4 [2-6]; P = .003, Wilcoxon rank-sum) but not day 3 (liposomal vs standard bupivacaine, 3 [2-6] vs 3 [1-5]; P = .10, Wilcoxon rank-sum), irrespective of treatment group. Median (IQR) 3-day cumulative NRS was 12.0 (8.0-16.5) for bupivacaine and 13.5 (9.0-17.0) for liposomal bupivacaine (P = .15, Wilcoxon rank-sum) Furthermore, use of opioids was greater following liposomal bupivacaine compared with standard bupivacaine (median [IQR], 41.5 [21.3-73.8] MEU vs 33.0 [17.8-62.5] MEU; P = .03, Wilcoxon rank-sum). On multivariable analysis, no interaction by incision type was observed for mean pain scores or opioid use.

CONCLUSIONS AND RELEVANCE

In this randomized clinical trial involving truncal incisions for cardiovascular procedures, liposomal bupivacaine did not provide improved pain control and did not reduce adjunctive opioid use compared with conventional bupivacaine formulation over 3 postoperative days.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02111746.

Liposomal bupivacaine interscalene nerve block in shoulder arthroplasty is not superior to plain bupivacaine: a double-blinded prospective randomized control trial

BACKGROUND

Interscalene brachial plexus blocks are a common modality used to provide adjunctive pain relief with shoulder replacement surgery. In 2018, the Federal Drug Administration approved the use of liposomal bupivacaine (LB) for such nerve blocks. We sought to evaluate whether this formulation of bupivacaine would provide superior pain relief for shoulder replacement patients over standard bupivacaine alone. Our hypotheses were that in the LB cohort the average postoperative pain score over the first 72 hours would be significantly lower, time to block cessation would be longer, total opioid consumption would be lower, and the average patient satisfaction score regarding their pain management would be higher.

MATERIALS AND METHODS

A randomized, double-blinded study was designed comparing primary shoulder replacement surgery after an interscalene block with 25 mL of 0.5% plain bupivacaine vs. 133 mg of LB with 7.5 mL of 0.5% and 7.5 mL of 0.25% plain bupivacaine. A total of 104 patients were included in the study, with an equal number in each study arm. Patients' visual analog pain scores (VAPS) were followed for their inpatient stay, first 3 full outpatient days, and at a 3-week follow-up. Use of opioid medication was recorded for the same intervals and converted to morphine milligram equivalents. The time to first opioid rescue was documented, as well as the patients' satisfaction with their pain management at both the 3-day and 3-week intervals.

RESULTS

No clinically relevant advantage to the use of LB over plain bupivacaine was found. During the second postoperative day, the mean VAPS was 2.4 with LB vs. 3.3 in the standard cohort (P = .0409). The only other statistically significant finding was a higher VAPS with LB during the third full day home compared with standard bupivacaine (4.0 vs. 2.8, respectively, P = .0197). Both of these differences were less than the minimal clinically important difference of 2 for the VAPS. Analysis of the VAPS for the first and third postoperative days, the first and second full days home, and at 3 weeks revealed no significant difference. Similarly, there was no significant difference in time to first opioid rescue, total morphine milligram equivalent use, and patient satisfaction with pain management.

CONCLUSION

When used for an interscalene block to provide adjunctive pain relief in shoulder replacement surgery, the addition of LB to plain bupivacaine provides no additional clinically important benefit to the patient's pain experience over standard bupivacaine.

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

BACKGROUND

Liposomal bupivacaine is purported to extend analgesia of peripheral nerve blocks when administered perineurally. However, evidence of the clinical effectiveness of perineural liposomal bupivacaine is mixed. This meta-analysis seeks to evaluate the effectiveness of perineural liposomal bupivacaine in improving peripheral nerve block analgesia as compared with nonliposomal local anesthetics.

METHODS

The authors identified randomized trials evaluating the effectiveness of peripheral nerve block analgesic that compared liposomal bupivacaine with nonliposomal local anesthetics. The primary outcome was the difference in area under the receiver operating characteristics curve (AUC) of the pooled 24- to 72-h rest pain severity scores. Secondary outcomes included postoperative analgesic consumption, time to first analgesic request, incidence of opioid-related side effects, patient satisfaction, length of hospital stay, liposomal bupivacaine side effects, and functional recovery. AUC pain scores were interpreted in light of a minimal clinically important difference of 2.0 cm · h.

RESULTS

Nine trials (619 patients) were analyzed. When all trials were pooled, AUC pain scores ± SD at 24 to 72 h were 7.6 ± 4.9 cm · h and 6.6 ± 4.6 cm · h for nonliposomal and liposomal bupivacaine, respectively. As such, perineural liposomal bupivacaine provided a clinically unimportant benefit by improving the AUC (95% CI) of 24- to 72-h pain scores by 1.0 cm · h (0.5 to 1.6; P = 0.003) compared with nonliposomal bupivacaine. Excluding an industry-sponsored trial rendered the difference between the groups nonsignificant (0.7 cm · h [-0.1 to 1.5]; P = 0.100). Secondary outcome analysis did not uncover any additional benefits to liposomal bupivacaine in pain severity at individual timepoints up to 72 h, analgesic consumption, time to first analgesic request, opioid-related side effects, patient satisfaction, length of hospital stay, and functional recovery. No liposomal bupivacaine side effects were reported.

CONCLUSIONS

Perineural liposomal bupivacaine provided a statistically significant but clinically unimportant improvement in the AUC of postoperative pain scores compared with plain local anesthetic. Furthermore, this benefit was rendered nonsignificant after excluding an industry-sponsored trial, and liposomal bupivacaine was found to be not different from plain local anesthetics for postoperative pain and all other analgesic and functional outcomes. High-quality evidence does not support the use of perineural liposomal bupivacaine over nonliposomal bupivacaine for peripheral nerve blocks.

EDITOR’S PERSPECTIVE

Clinical Effectiveness of Liposomal Bupivacaine Administered by Infiltration or Peripheral Nerve Block to Treat Postoperative Pain

The authors provide a comprehensive summary of all randomized, controlled trials (n = 76) involving the clinical administration of liposomal bupivacaine (Exparel; Pacira Pharmaceuticals, USA) to control postoperative pain that are currently published. When infiltrated surgically and compared with unencapsulated bupivacaine or ropivacaine, only 11% of trials (4 of 36) reported a clinically relevant and statistically significant improvement in the primary outcome favoring liposomal bupivacaine. Ninety-two percent of trials (11 of 12) suggested a peripheral nerve block with unencapsulated bupivacaine provides superior analgesia to infiltrated liposomal bupivacaine. Results were mixed for the 16 trials comparing liposomal and unencapsulated bupivacaine, both within peripheral nerve blocks. Overall, of the trials deemed at high risk for bias, 84% (16 of 19) reported statistically significant differences for their primary outcome measure(s) compared with only 14% (4 of 28) of those with a low risk of bias. The preponderance of evidence fails to support the routine use of liposomal bupivacaine over standard local anesthetics.

Liposomal Bupivacaine Infiltration After Median Sternotomy in Pediatric Cardiac Surgery

OBJECTIVE

The present study retrospectively ascertained whether liposomal bupivacaine (LB) injected subcutaneously after median sternotomy incisions in pediatric cardiac surgery patients is as efficacious as the ON-Q PainBuster pump (ON-Q) (Avonas Medical, Alpharetta, GA).

DESIGN

Retrospective cohort comparison.

SETTING

Pediatric hospital.

PARTICIPANTS

Cardiac surgery patients who were treated with LB for elective cardiac surgery.

INTERVENTIONS

Patients received 4 mg/kg of LB admixed with 0.25% bupivacaine and 0.9% normal saline. These patients were compared with an age- and procedure-matched control group of similar size treated with the ON-Q pump (continuous infusion 0.25% bupivacaine via subcutaneous catheter). Total analgesics used and route, other analgesics or sedatives, and pain scores (first 24 hours and cumulative) were tracked for 96 hours after surgery.

MEASUREMENTS AND MAIN RESULTS

A total of 222 patients were equally divided between the two groups. Overall, the median (interquartile range) age was 6.5 (3.8-12.7) years. Unadjusted analysis suggested that patients in the LB group were administered a significantly higher dose of intravenous acetaminophen (77.4 v 60.0 mg/kg; p < 0.05). Extubation in the operating room was significantly higher in the LB patients (p < 0.05). Narcotic (morphine) administration was significantly higher in the ON-Q group (100.0% v 95.5%; p < 0.05). Although the median pain score within the first 24 hours was higher in LB patients (27.0 v 17.0; p < 0.05), there was a significantly greater difference observed in the Numeric Rating Scale area under the curve for the ON-Q group.

CONCLUSIONS

LB is at least as effective as the ON-Q is for providing analgesia after median sternotomy incision in children.