Current Issues in the Use of Opioids for the Management of Postoperative Pain: A Review

Efficacy of intraoperative systemic lidocaine on quality of recovery after laparoscopic colorectal surgery: a randomized controlled trial

INTRODUCTION

Many clinical trials have demonstrated the benefits of intraoperative systemic lidocaine administration in major abdominal surgeries. We tested the hypothesis that systemic lidocaine is associated with an enhanced early quality of recovery in patients following laparoscopic colorectal resection.

PATIENTS AND METHODS

We randomly allocated 126 patients scheduled for laparoscopic colorectal surgery in a 1:1 ratio to receive either lidocaine (1.5 mg kg-1 bolus over 10 min, followed by continuous infusion at 2 mg kg-1 h-1 until the end of surgery) or identical volumes and rates of saline. The primary outcome was the Quality of Recovery-15 score assessed 24 h after surgery. Secondary outcomes were areas under the pain numeric rating scale curve over time, 48-h morphine consumption, and adverse events.

RESULTS

Compared with saline, systemic lidocaine improved the Quality of Recovery-15 score 24 h postoperatively, with a median difference of 4 (95% confidence interval: 1-6; p = 0.015). Similarly, the area under the pain numeric rating scale curve over 48 h at rest and on movement was reduced in the lidocaine group (p = 0.004 and p < 0.001, respectively). However, these differences were not clinically meaningful. Lidocaine infusion reduced the intraoperative remifentanil requirements but not postoperative 48-h morphine consumption (p < 0.001 and p = 0.34, respectively). Additionally, patients receiving lidocaine had a quicker and earlier return of bowel function, as indicated by a shorter time to first flatus (log-rank p < 0.001), yet ambulation time was similar between groups (log-rank test, p = 0.11).

CONCLUSIONS

In patients undergoing laparoscopic colorectal surgery, intraoperative systemic lidocaine resulted in statistically but not clinically significant improvements in quality of recovery (see Graphical Abstract).Trial registration: Chinese Clinical Trial Registry; ChiCTR1900027635.

Postsurgical tactile-evoked pain: a role for brain-derived neurotrophic factor-tropomyosin receptor kinase B-dependent novel tactile corpuscles

Introduction

Millions of people undergo surgical procedures each year with many developing postsurgical pain. Dynamic allodynia can arise when, for example, clothing brushing close to the surgical site elicits pain. The allodynia circuits that enable crosstalk between afferent tactile inputs and central pain circuits have been studied, but the peripheral tactile drive has not been explored.

Objective

Investigate the innervation of the skin in the rat plantar hindpaw skin-muscle incision model.

Results

Incision increased epidermal thickness and cell layers and reduced intraepidermal nerve fibre density, identified with PGP9.5 immunostaining. Strikingly, Collagen IV immunostaining revealed the development of dermal protrusions, oriented towards the incision site, that were reminiscent of the dermal papillae that exist in glabrous footpads. S100 immunostaining for lamellar Schwann cells revealed the presence of novel tactile corpuscles (S100-positive bulb) within incision-induced putative dermal papillae. The occurrence of these novel tactile corpuscles coincided with behavioural observations of dynamic allodynia. Tactile corpuscles require brain-derived neurotrophic factor- tropomyosin receptor kinase B (BDNF-TrkB) signalling to form during development, and an increase in BDNF-immunostaining intensity was observed close to the incision site. Local acute administration of TrkB-Fc, to block BDNF-TrkB signalling, reduced, by approximately 50%, both tactile corpuscle size (S100+ bulb area) and dynamic allodynia.

Conclusion

Surgery induces the development of novel tactile corpuscles in the incision surround, in a BDNF-TrKB-dependent manner, that contributes to postsurgical tactile-evoked pain.

The WHO guidelines: the new and the old

PURPOSE OF THE REVIEW

The original World Health Organisation (WHO) cancer pain guidelines were published in 1986 and used globally. Updated guidance was released in 2018. This review compares the 'old' with the 'new' with a closer look at the relevance of the WHO analgesic ladder in the current climate.

RECENT FINDINGS

The new guidelines provide a more evidence based, rigorously developed document including recommendations relating to radiotherapeutic management. There is a more detailed focus on safe opioid prescribing, opioid stewardship and the importance of integrating pain management expertise early on in the cancer journey. There remains a lack of evidence for certain therapies despite their widespread use particularly in relation to adjuvants. The pitfalls of the original renowned analgesic ladder are highlighted including a recognition that omitting 'step 2' is safe, feasible and cost effective.

SUMMARY

The new guidelines offer more detailed recommendations relevant to clinical practice with a strong focus on safety of opioid prescribing making it relevant in the current climate. The original WHO analgesic ladder is no longer recommended as a strict protocol for cancer pain management.

Recommendation for the practice of total intravenous anesthesia

This Recommendation was developed by the Japanese Society of Intravenous Anesthesia Recommendation Making Working Group (JSIVA-WG) to promote the safe and effective practice of total intravenous anesthesia (TIVA), tailored to the current situation in Japan. It presents a policy validated by the members of JSIVA-WG and a review committee for practical anesthesia management. Anesthesiologists should acquire and maintain the necessary knowledge and skills to be able to administer TIVA properly. A secure venous access is critically important for TIVA. To visualize and understand the pharmacokinetics of intravenous anesthetics, use of real-time pharmacokinetic simulations is strongly recommended. Syringe pumps are essential for the infusion of intravenous anesthetics, which should be prepared according to the rules of each individual anesthesia department, particularly with regard to dilution. Syringes should be clearly labeled with content and drug concentration. When managing TIVA, particularly with the use of muscle relaxants, monitoring processed electroencephalogram (EEG) is advisable. However, the depth of sedation/anesthesia must be assessed comprehensively using various parameters, rather than simply relying on a single EEG index. TIVA should be swiftly changed to an alternative method that includes inhalation anesthesia if necessary. Use of antagonists at emergence may be associated with re-sedation risk. Casual administration of antagonists and sending patients back to surgical wards without careful observation are not acceptable.

Mitigating and preventing perioperative opioid-related harm

PURPOSE OF REVIEW

Although necessary for treatment of acute pain, opioids are associated with significant harm in the perioperative period and further intervention is necessary perioperatively to mitigate opioid-related harm.

RECENT FINDINGS

Opioid-naive patients are often first exposed to opioids when undergoing surgery, which can result in significant harm. Despite their benefits in reducing acute postsurgical pain, they are also associated with risks ranging from mild (e.g., pruritis, constipation, nausea) to potentially catastrophic (e.g. opioid-induced ventilatory impairment, respiratory depression, death). Overprescribing of opioids can lead to opioid diversion and drug driving. In this review, we will discuss opioid-related harm and what strategies can be used perioperatively to mitigate this harm. Interventions such as optimizing nonopioid analgesia, implementing Enhanced Recovery after Surgery programs, effective respiratory monitoring, patient education and opioid stewardship programs will be discussed.

SUMMARY

We will review policy and guidelines regarding perioperative opioid management and identify challenges and future directions to mitigate opioid-related harm.

Integrating mechanistic-based and classification-based concepts into perioperative pain management: an educational guide for acute pain physicians

Chronic pain begins with acute pain. Physicians tend to classify pain by duration (acute vs chronic) and mechanism (nociceptive, neuropathic and nociplastic). Although this taxonomy may facilitate diagnosis and documentation, such categories are to some degree arbitrary constructs, with significant overlap in terms of mechanisms and treatments. In clinical practice, there are myriad different definitions for chronic pain and a substantial portion of chronic pain involves mixed phenotypes. Classification of pain based on acuity and mechanisms informs management at all levels and constitutes a critical part of guidelines and treatment for chronic pain care. Yet specialty care is often siloed, with advances in understanding lagging years behind in some areas in which these developments should be at the forefront of clinical practice. For example, in perioperative pain management, enhanced recovery protocols are not standardized and tend to drive treatment without consideration of mechanisms, which in many cases may be incongruent with personalized medicine and mechanism-based treatment. In this educational document, we discuss mechanisms and classification of pain as it pertains to commonly performed surgical procedures. Our goal is to provide a clinical reference for the acute pain physician to facilitate pain management decision-making (both diagnosis and therapy) in the perioperative period.

Deep learning predicts postoperative opioids refills in a multi-institutional cohort of surgical patients

BACKGROUND

To combat the opioid epidemic, several strategies were implemented to limit the unnecessary prescription of opioids in the postoperative period. However, this leaves a subset of patients who genuinely require additional opioids with inadequate pain control. Deep learning models are powerful tools with great potential of optimizing health care delivery through a patient-centered focus. We sought to investigate whether deep learning models can be used to predict patients who would require additional opioid prescription refills in the postoperative period after elective surgery.

METHODS

This is a retrospective study of patients who received elective surgical intervention at the Mayo Clinic. Adult English-speaking patients ≥18 years old, who underwent an elective surgical procedure between 2013 and 2019, were eligible for inclusion. Machine learning models, including deep learning, random forest, and eXtreme Gradient Boosting, were designed to predict patients who require opioid refills after discharge from hospital.

RESULTS

A total of 9,731 patients with mean age of 62.1 years (51.4% female) were included in the study. Deep learning and random forest models predicted patients who required opioid refills with high accuracy, 0.79 ± 0.07 and 0.78 ± 0.08, respectively. Procedure performed, highest pain score recorded during hospitalization, and total oral morphine milligram equivalents prescribed at discharge were the top 3 predictors for requiring opioid refills after discharge.

CONCLUSION

Deep learning models can be used to predict patients who require postoperative opioid prescription refills with high accuracy. Other machine learning models, such as random forest, can perform equal to deep learning, increasing the applicability of machine learning for combating the opioid epidemic.

Dexborneol Amplifies Pregabalin's Analgesic Effect in Mouse Models of Peripheral Nerve Injury and Incisional Pain

Pregabalin is a medication primarily used in the treatment of neuropathic pain and anxiety disorders, owing to its gabapentinoid properties. Pregabalin monotherapy faces limitations due to its variable efficacy and dose-dependent adverse reactions. In this study, we conducted a comprehensive investigation into the potentiation of pregabalin's analgesic effects by dexborneol, a neuroprotective bicyclic monoterpenoid compound. We performed animal experiments where pain models were induced using two methods: peripheral nerve injury, involving axotomy and ligation of the tibial and common peroneal nerves, and incisional pain through a longitudinal incision in the hind paw, while employing a multifaceted methodology that integrates behavioral pharmacology, molecular biology, neuromorphology, and lipidomics to delve into the mechanisms behind this potentiation. Dexborneol was found to enhance pregabalin's efficacy by promoting its transportation to the central nervous system, disrupting self-amplifying vicious cycles via the reduction of HMGB1 and ATP release, and exerting significant anti-oxidative effects through modulation of central lipid metabolism. This combination therapy not only boosted pregabalin's analgesic property but also notably decreased its side effects. Moreover, this therapeutic cocktail exceeded basic pain relief, effectively reducing neuroinflammation and glial cell activation-key factors contributing to persistent and chronic pain. This study paves the way for more tolerable and effective analgesic options, highlighting the potential of dexborneol as an adjuvant to pregabalin therapy.

Clinical and surgical factors associated with opioid refill rates following septorhinoplasty

BACKGROUND

Septorhinoplasty is one the most common class of procedures performed worldwide, and opioids are frequently prescribed for post-operative pain [1].

OBJECTIVE

The objective of this study was to examine the rate of post-operative opioid prescription refills following septorhinoplasty.

METHODS

This study was a case-control study of patients who underwent septoplasty and other secondary concomitant procedures.

RESULTS

Of the 249 patients included in this study, the majority of patients (94.8%) were prescribed 12 tablets of hydrocodone-acetaminophen 5 mg - 325 mg and only 31 patients (13.3%) received refills. The presence of osteotomies and history of prior opioid use were associated with refills. Nasal valve repair type, open versus closed approach, and presence of autologous auricular cartilage graft harvest were not.

DISCUSSION

Our study highlights factors that surgeons should consider when prescribing opioids after septorhinoplasty. Twelve tablets of an opioid are likely sufficient for the majority of patients, but if osteotomies are performed or the patient has a history of prior opioid use, more may be indicated to avoid the need for refills. Additional narcotics are not necessary for an open approach or for patients in which auricular cartilage is needed.

Optimizing patient-controlled analgesia: a narrative review based on a single center audit process

Intravenous patient-controlled analgesia (PCA) is valuable for delivering opioids in a flexible and timely manner. Although it is designed to offer personalized analgesia driven by the patients themselves, users often report insufficient pain relief, which can be addressed by optimizing its settings and multimodal analgesia. We adopted a systematic approach to modify PCA protocols by utilizing a serial audit process based on institutional PCA data. This review retrospectively examined the process, encompassing data from 13,230 patients who had used PCA devices. The two modifications to the fentanyl-based PCA protocols resulted in three distinct phases. In the first phase, high opioid consumption and unintended PCA withdrawal were the common issues. These were addressed in the second phase by omitting the routine use of basal infusion. However, this led to increased delivery-to-demand ratios, mitigated in the third phase by increasing the bolus dose from 15 μg to 20 μg. These serial protocol changes have produced varied outcomes across different surgical departments, underscoring the need for careful and gradual adjustments and thorough impact assessments. Drawing insights from this audit process, we incorporated findings from the literature on PCA settings and multimodal analgesic approaches. This review underscores the significance of iterative feedback and refinement of analgesic protocols to achieve optimal postoperative pain management. Additionally, it discusses critical considerations regarding the postoperative audit processes.

Postoperative opioids administered to inpatients with major or orthopaedic surgery: A retrospective cohort study using data from hospital electronic prescribing systems

BACKGROUND

Opioids administered in hospital during the immediate postoperative period are likely to influence post-surgical outcomes, but inpatient prescribing during the admission is challenging to access. Modified-release(MR) preparations have been especially associated with harm, whilst certain populations such as the elderly or those with renal impairment may be vulnerable to complications. This study aimed to assess postoperative opioid utilisation patterns during hospital stay for people admitted for major/orthopaedic surgery.

METHODS

Patients admitted to a teaching hospital in the North-West of England between 2010-2021 for major/orthopaedic surgery with an admission for ≥1 day were included. We examined opioid administrations in the first seven days post-surgery in hospital, and "first 48 hours" were defined as the initial period. Proportions of MR opioids, initial immediate-release(IR) oxycodone and initial morphine milligram equivalents (MME)/day were calculated and summarised by calendar year. We also assessed the proportion of patients prescribed an opioid at discharge.

RESULTS

Among patients admitted for major/orthopaedic surgery, 71.1% of patients administered opioids during their hospitalisation. In total 50,496 patients with 60,167 hospital admissions were evaluated. Between 2010-2017 MR opioids increased from 8.7% to 16.1% and dropped to 11.6% in 2021. Initial use of oxycodone IR among younger patients (≤70 years) rose from 8.3% to 25.5% (2010-2017) and dropped to 17.2% in 2021. The proportion of patients on ≥50MME/day ranged from 13% (2021) to 22.9% (2010). Of the patients administered an opioid in hospital, 26,920 (53.3%) patients were discharged on an opioid.

CONCLUSIONS

In patients hospitalised with major/orthopaedic surgery, 4 in 6 patients were administered an opioid. We observed a high frequency of administered MR opioids in adult patients and initial oxycodone IR in the ≤70 age group. Patients prescribed with ≥50MME/day ranged between 13-22.9%. This is the first published study evaluating UK inpatient opioid use, which highlights opportunities for improving safer prescribing in line with latest recommendations.

Systemic lidocaine versus erector spinae plane block for improving quality of recovery after laparoscopic cholecystectomy: A randomized controlled trial

STUDY OBJECTIVE

To compare intravenous lidocaine, ultrasound-guided erector spinae plane block (ESPB), and placebo on the quality of recovery and analgesia after laparoscopic cholecystectomy.

DESIGN

A prospective, triple-arm, double-blind, randomized, placebo-controlled non-inferiority trial.

SETTING

A single tertiary academic medical center.

PATIENTS

126 adults aged 18-65 years undergoing elective laparoscopic cholecystectomy.

INTERVENTIONS

Patients were randomly allocated to one of three groups: intravenous lidocaine infusion (1.5 mg/kg bolus followed by 2 mg/kg/h) plus bilateral ESPB with saline (25 mL per side); bilateral ESPB with 0.25% ropivacaine (25 ml per side) plus placebo infusion; or bilateral ESPB with saline (25 ml per side) plus placebo infusion.

MEASUREMENTS

The primary outcome was the 24-h postoperative Quality of Recovery-15 (QoR-15) score. The non-inferiority of lidocaine versus ESPB was assessed with a margin of -6 points and 97.5% confidence interval (CI). Secondary outcomes included 24-h area under the curve (AUC) for pain scores, morphine consumption, and adverse events.

MAIN RESULTS

124 patients completed the study. Median (IQR) 24-h QoR-15 scores were 123 (117-127) for lidocaine, 124 (119-126) for ESPB, and 112 (108-117) for placebo. Lidocaine was non-inferior to ESPB (median difference  -1, 97.5% CI: -4 to ∞). Both lidocaine (median difference 9, 95% CI: 6-12, P < 0.001) and ESPB (median difference 10, 95% CI: 7-13, P < 0.001) were superior to placebo. AUC for pain scores and morphine use were lower with lidocaine and ESPB versus placebo (P < 0.001 for all), with no significant differences between lidocaine and ESPB. One ESPB patient reported a transient metallic taste; no other block-related complications occurred.

CONCLUSIONS

For patients undergoing laparoscopic cholecystectomy, intravenous lidocaine provides a non-inferior quality of recovery compared to ESPB without requiring specialized regional anesthesia procedures. Lidocaine may offer a practical and accessible alternative within multimodal analgesia pathways.

Acupoint Stimulation for Pain Control in Enhanced Recovery After Surgery: Systematic Review and Meta-Analysis

Introduction: Postoperative pain control is a challenge in enhanced recovery after surgery (ERAS). The current study reviewed the efficacy and safety of incorporating acupoint stimulation for postoperative pain control in ERAS. Methods: Ten databases for relevant randomized controlled trials (RCTs) published in English or Mandarin Chinese were searched from 1997 to 2022. The quality of each article was appraised using the Cochrane Collaboration Risk of Bias Criteria and the modified Jadad Scale. The primary outcome was pain control, measured using the visual analog scale 24 h after surgery. Results: Eleven trials met the eligibility criteria and were included in the study. Acupoint stimulation was found more effective than control treatments in terms of pain intensity (standardized mean difference [SMD] -0.94; 95% confidence interval [CI] -1.35 to -0.53), analgesic drug consumption (SMD -1.87; 95% CI -2.98 to -0.75), postoperative nausea (PON; SMD 0.31; 95% CI 0.13 to 0.73), postoperative vomiting (POV; SMD 0.57; 95% CI 0.11 to 2.92), and PON and POV (PONV; SMD 0.29; 95% CI 0.16 to 0.53). The Zusanli (ST36) and Neiguan (PC6) were the most-used acupoints in the included trials (8/11). The reported adverse reaction was only one case of bruising. Discussion: Acupoint stimulation improved pain control in patients undergoing ERAS more than control treatments. The findings provide an evidence-based premise for incorporating acupoint stimulation into ERAS strategies. More rigorous RCTs are needed in the future.

The Development and Implementation of the Fast-Pace Assessment Framework and Tiered Analgesic Orders for Opioid Optimization

BACKGROUND

Within the context of the opioid epidemic, changes needed to be made in the prescription and administration of analgesics. The purpose of this paper is to describe the development and implementation of a project that utilized a holistic pain assessment framework and introduced new order sets to guide the integration of nonopioid, opioid, and co-analgesics in a quaternary care medical center.

METHODS

An interdisciplinary team updated policies and procedures for pain assessment and opioid administration and created new analgesic order sets for both adult and pediatric patients. Following requisite approvals, these order sets were integrated into the electronic health record. Education of clinicians, patients, and caregivers was provided to facilitate implementation of these new clinical practices.

RESULTS

Prescribers' levels of adherence with the use of the pain order sets ranged from 80% to 90% and no adverse effects were reported. Education of nursing staff was incorporated into hospital orientation. Ongoing evaluations are providing insights into how the new policies and procedures can be optimized to ensure reliable, safe, and effective pain management.

CONCLUSIONS

Since the implementation of the opioid optimization project, adherence with the tiered, multimodal approach to analgesic prescribing is high. Next steps include both qualitative and quantitative evaluations of the benefits and challenges associated with this practice change. For example, systems will be developed to monitor nurses' adherence with the implementation of the pain order sets and the use of both pharmacologic and nonpharmacologic pain management interventions.

Balanced opioid-free anesthesia with lidocaine and esketamine versus balanced anesthesia with sufentanil for gynecological endoscopic surgery: a randomized controlled trial

In this randomized controlled trial, 74 patients scheduled for gynecological laparoscopic surgery (American Society of Anesthesiologists grade I/II) were enrolled and randomly divided into two study groups: (i) Group C (control), received sufentanil (0.3 μg/kg) and saline, followed by sufentanil (0.1 μg/kg∙h) and saline; and (ii) Group F (OFA), received esketamine (0.15 mg/kg) and lidocaine (2 mg/kg), followed by esketamine (0.1 mg/kg∙h) and lidocaine (1.5 mg/kg∙h). The primary outcome was the 48-h time-weighted average (TWA) of postoperative pain scores. Secondary outcomes included time to extubation, adverse effects, and postoperative sedation score, pain scores at different time points, analgesic consumption at 48 h, and gastrointestinal functional recovery. The 48-h TWAs of pain scores were 1.32 (0.78) (95% CI 1.06-1.58) and 1.09 (0.70) (95% CI 0.87-1.33) for Groups F and C, respectively. The estimated difference between Groups F and C was - 0.23 (95% CI - 0.58 - 0.12; P = 0.195). No differences were found in any of the secondary outcomes and no severe adverse effects were observed in either group. Balanced OFA with lidocaine and esketamine achieved similar effects to balanced anesthesia with sufentanil in patients undergoing elective gynecological laparoscopic surgery, without severe adverse effects.Clinical Trial Registration: ChiCTR2300067951, www.chictr.org.cn 01 February, 2023.

Opioid-free Anesthesia Protocol on the Early Quality of Recovery after Major Surgery (SOFA Trial): A Randomized Clinical Trial

BACKGROUND

Opioid-free anesthesia is increasingly being adopted to reduce opioid consumption, but its impact on early postoperative recovery after major surgery has not been evaluated in comparative trials. The hypothesis was that an opioid-free anesthesia protocol would enhance the early quality of recovery for patients undergoing scheduled major surgery under general anesthesia.

METHODS

The SOFA study was a monocentric, randomized, controlled, assessor- and patient-blinded clinical trial conducted from July 10, 2021, to February 12, 2022. The eligible population included male and female patients undergoing scheduled major surgery, excluding bone procedures, that typically require opioids for postoperative pain management. Patients in the intervention group received a combination of at least two drugs among ketamine, lidocaine, clonidine, and magnesium sulfate, without opioids for anesthesia. The standard group received opioids. The primary outcome was early postoperative quality of recovery, assessed by Quality of Recovery-15 score at 24 h after surgery. Secondary outcomes were Quality of Recovery-15 at 48 and 72 h after surgery, incidence of chronic pain, and quality of life at 3 months.

RESULTS

Of the 136 randomized patients, 135 were included in the primary analysis (mean age, 45.9 ± 15.7 yr; 116 females [87.2%]; 85 underwent major plastic surgery [63.9%]), with 67 patients in the opioid-free anesthesia group and 68 in the standard group. The mean Quality of Recovery-15 at 24 h was 114.9 ± 15.2 in the opioid-free anesthesia group versus 108.7 ± 18.1 in the standard group (difference, 6.2; 95% CI, 0.4 to 12.0; P = 0.026). Quality of Recovery-15 scores also differed significantly at 48 h (difference, 8.7; 95% CI, 2.9 to 14.5; P = 0.004) and at 72 h (difference, 7.3; 95% CI, 1.6 to 13.0; P = 0.013). There were no differences in other secondary outcomes. No major adverse events were noticed.

CONCLUSIONS

The opioid-free anesthesia protocol improved quality of recovery after major elective surgery in a statistically but not clinically significant manner when compared to standard anesthesia.

EDITOR’S PERSPECTIVE

Efficacy of high-voltage, long-duration pulsed radiofrequency for the treatment of acute herpes zoster-related trigeminal neuralgia in a patient with permanent pacemaker

Background

Recognizing the seriousness of the misuse and abuse of medical narcotics, the South Korean government introduced the world's first narcotic management system, the Narcotics Information Management System (NIMS). This study aimed to explore the recent one-year opioid prescribing patterns in South Korea using the NIMS database.

Methods

This study analyzed opioid prescription records in South Korea for the year 2022, utilizing the dispensing/administration dataset provided by NIMS. Public data from the Korean Statistical Information Service were also utilized to explore prescription trends over the past four years. The examination covered 16 different opioid analgesics, assessed by the total number of units prescribed based on routes of administration, type of institutions, and patients’ sex and age group. Additionally, the disposal rate for each ingredient was computed.

Results

In total, 206,941 records of 87,792,968 opioid analgesic units were analyzed. Recently, the overall quantity of prescribed opioid analgesic units has remained relatively stable. The most prescribed ingredient was oral oxycodone, followed by tapentadol and sublingual fentanyl. Tertiary hospitals had the highest number of dispensed units (49.4%), followed by community pharmacies (40.2%). The highest number of prescribed units was attributed to male patients in their 60s. The disposal rates of the oral and transdermal formulations were less than 0.1%.

Conclusions

Opioid prescription in South Korea features a high proportion of oral formulations, tertiary hospital administration, pharmacy dispensing, and elderly patients. Sustained education and surveillance of patients and healthcare providers is required.

Identification of (4-chlorophenyl)(5-hydroxynaphtho[1,2-b]furan-3-yl)methanone as novel COX-2 inhibitor with analgesic profile

Chronic pain is a serious problem that affects billions of people worldwide, but current analgesic drugs limit their use in chronic pain management due to their respective side effects. As a first-line clinical drug for chronic pain, COX-2 selective inhibitors can relieve mild to moderate pain, but they also have some problems. The most prominent one is that their analgesic intensity is not enough, and they cannot well meet the treatment needs of chronic pain. Therefore, there is an urgent need to develop COX-2 inhibitors with stronger analgesic intensity. In this article, we used virtual screening method to screen out the structurally novel COX-2 inhibitor for chronic pain management, and conducted a preliminary study on its mechanism of action using molecular dynamics simulation.

Microglial Nrf2/HO-1 signaling gates remifentanil-induced hyperalgesia via suppressing TRPV4-mediated M1 polarization

Remifentanil-induced hyperalgesia (RIH) represents a significant clinical challenge due to the widespread use of opioids in pain management. However, the molecular and cellular mechanisms underlying RIH remain elusive. This study aimed to unravel the role of spinal cord microglia, focusing on the Nrf2/HO-1 signaling pathway and TRPV4 channels in the development of RIH. We used both in vivo and in vitro models to investigate the activation state of spinal cord microglia, the expression of TRPV4 channels, and the modulation of the Nrf2/HO-1 pathway under remifentanil exposure. In addition, we evaluated the potential therapeutic effects of dexmedetomidine, a perioperative α2-adrenergic agonist, on RIH and its related molecular pathways. Our results revealed a prominent role of spinal cord microglia in RIH, demonstrating an apparent microglial M1 polarization and increased TRPV4 channel expression. A notable observation was the downregulation of the Nrf2/HO-1 pathway, which was associated with increased neuroinflammation and mechanical allodynia. By upregulating or overexpressing Nrf2, we confirmed its ability to inhibit TRPV4 and thereby attenuate RIH-associated mechanical allodynia, M1 polarization, and neuroinflammation. Encouragingly, dexmedetomidine demonstrated therapeutic potential by positively modulating the Nrf2-TRPV4 nexus, attenuating mechanical allodynia, and reducing microglial inflammation. Our research highlights the critical role of spinal cord microglia in RIH mediated by the Nrf2-TRPV4 axis. The ability of dexmedetomidine to modulate this axis suggests its potential as an adjunctive therapy to remifentanil in mitigating RIH. Further studies are imperative to explore the broader implications and practical applicability of our findings.

Effect of opioid-free anesthesia on postoperative nausea and vomiting after gynecological surgery: a systematic review and meta-analysis

Background: Postoperative nausea and vomiting (PONV) is a common complication, that can reduce patient satisfaction and may lead to serious consequences, such as wound dehiscence. Many strategies have been proposed to prevent PONV; however, it remains common, especially in high-risk surgeries such as gynecological surgery. In recent years, opioid-free anesthesia has been widely studied because it minimizes adverse reactions of opioids, such as nausea, vomiting, and itching; however, conclusions have been inconsistent. Therefore, we conducted this meta-analysis to investigate the effects of opioid-free anesthesia on PONV in patients undergoing gynecological surgery. Methods: A systematic search of the PubMed, Web of Science, Cochrane Library, and Embase databases, from inception to 28 August 2023, was performed. Keywords and other free terms were used with Boolean operators (OR and, AND) to combine searches. This review was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Results: Six studies involving 514 patients who underwent gynecological surgery were included. The forest plot revealed that the incidence of PONV (risk ratio = 0.52; p < 0.00001) and consumption of postoperative antiemetics use (risk ratio = 0.64; p = 0.03) were significantly lower in the opioid-free anesthesia group. In addition, opioid-free anesthesia improved the quality of recovery (mean difference = 4.69; p < 0.0001). However, there were no significant differences in postoperative pain scores (mean difference = 0.05; p = 0.85), analgesic use (risk ratio = 1.09; p = 0.65), and the time of extubation (mean difference = -0.89; p = 0.09) between the opioid-free anesthesia and control groups. Conclusion: OFA reduces PONV and the use of antiemetic drugs. In addition, it improves the quality of postoperative recovery. However, OFA can not reduce the postoperative pain scores, analgesic use and the time of extubation. Due to the strength of the evidence, we cannot support OFA as an ideal anesthesia method in gynecological surgery, and the implementation of anesthesia strategies should be case-by-case. Systematic Review Registration: [https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=462044], identifier [CRD42023462044].

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

BACKGROUND

Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.

METHODS

This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.

RESULTS

The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (β coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.

CONCLUSION

Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely.

Variation in Intraoperative Opioid Administration by Patient, Clinician, and Hospital Contribution

Importance

The opioid crisis has led to scrutiny of opioid exposures before and after surgical procedures. However, the extent of intraoperative opioid variation and the sources and contributing factors associated with it are unclear.

Objective

To analyze attributable variance of intraoperative opioid administration for patient-, clinician-, and hospital-level factors across surgical and analgesic categories.

Design, Setting, and Participants

This cohort study was conducted using electronic health record data collected from a national quality collaborative database. The cohort consisted of 1 011 268 surgical procedures at 46 hospitals across the US involving 2911 anesthesiologists, 2291 surgeons, and 8 surgical and 4 analgesic categories. Patients without ambulatory opioid prescriptions or use history undergoing an elective surgical procedure between January 1, 2014, and September 11, 2020, were included. Data were analyzed from January 2022 to July 2023.

Main Outcomes and Measures

The rate of intraoperative opioid administration as a continuous measure of oral morphine equivalents (OMEs) normalized to patient weight and case duration was assessed. Attributable variance was estimated in a hierarchical structure using patient, clinician, and hospital levels and adjusted intraclass correlations (ICCs).

Results

Among 1 011 268 surgical procedures (mean [SD] age of patients, 55.9 [16.2] years; 604 057 surgical procedures among females [59.7%]), the mean (SD) rate of intraoperative opioid administration was 0.3 [0.2] OME/kg/h. Together, clinician and hospital levels contributed to 20% or more of variability in intraoperative opioid administration across all analgesic and surgical categories (adjusting for surgical or analgesic category, ICCs ranged from 0.57-0.79 for the patient, 0.04-0.22 for the anesthesiologist, and 0.09-0.26 for the hospital, with the lowest ICC combination 0.21 for anesthesiologist and hosptial [0.12 for the anesthesiologist and 0.09 for the hospital for opioid only]). Comparing the 95th and fifth percentiles of opioid administration, variation was 3.3-fold among anesthesiologists (surgical category range, 2.7-fold to 7.7-fold), 4.3-fold among surgeons (surgical category range, 3.4-fold to 8.0-fold), and 2.2-fold among hospitals (surgical category range, 2.2-fold to 4.3-fold). When adjusted for patient and surgical characteristics, mean (square error mean) administration was highest for cardiac surgical procedures (0.54 [0.56-0.52 OME/kg/h]) and lowest for orthopedic knee surgical procedures (0.19 [0.17-0.21 OME/kg/h]). Peripheral and neuraxial analgesic techniques were associated with reduced administration in orthopedic hip (51.6% [95% CI, 51.4%-51.8%] and 60.7% [95% CI, 60.5%-60.9%] reductions, respectively) and knee (48.3% [95% CI, 48.0%-48.5%] and 60.9% [95% CI, 60.7%-61.1%] reductions, respectively) surgical procedures, but reduction was less substantial in other surgical categories (mean [SD] reduction, 13.3% [8.8%] for peripheral and 17.6% [9.9%] for neuraxial techniques).

Conclusions and Relevance

In this cohort study, clinician-, hospital-, and patient-level factors had important contributions to substantial variation of opioid administrations during surgical procedures. These findings suggest the need for a broadened focus across multiple factors when developing and implementing opioid-reducing strategies in collaborative quality-improvement programs.

Efficacy and Safety of Transdermal Buprenorphine for Acute Postoperative Pain: A Systematic Review and Meta-analysis

Transdermal buprenorphine (TBUP) may have some advantages for the management of acute postoperative pain. The aim of this systematic review and meta-analysis was to investigate the efficacy and safety of TBUP compared to other analgesics or placebo for acute postoperative pain. A systematic search was conducted using Embase, MEDLINE, and Cochrane Central Register of Controlled Trials (CENTRAL) until December 26, 2022. The search included randomized controlled trials comparing TBUP versus other analgesics or placebo for acute postoperative pain. A certainty assessment was conducted using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) method. The protocol for this review was registered on Prospective Register of Systematic Reviews (CRD42022318601). In total, 15 studies involving 1,205 participants were included that compared TBUP versus fentanyl (n = 2), celecoxib (n = 3), placebo (n = 2), tramadol (n = 5), diclofenac (n = 3), parecoxib (n = 1), and flurbiprofen (n = 1). Meta-analyses were conducted for 3 comparators that involved 2 studies each. There was no significant difference in pain between TBUP 10 mcg/h versus fentanyl 25 mcg/h (standardized mean difference [SMD] -.03, 95% confidence interval [CI] -.86 to .81, P = .95, I2 = 85%). TBUP 10 mcg/h was associated with less pain compared to celecoxib 200 mg twice daily (SMD -.32, 95% CI -.58 to -.05, P = .02, I2 = 0%) and placebo (SMD -2.29, 95% CI -4.32 to -.27, P = .03, I2 = 94%). The GRADE assessment showed a very low certainty of evidence for all comparisons. There is insufficient evidence that TBUP improves pain control compared to other analgesics for acute postoperative pain. PERSPECTIVE: This systematic review and meta-analysis compared the use of TBUP to other analgesics for postoperative pain. The results showed that there is insufficient evidence to recommend the use of TBUP in this setting. The findings will help clinicians select the most appropriate opioid regimens for postoperative pain.

Temporal trends and patterns in initial opioid prescriptions after hospital discharge following colectomy in England over 10 years

BACKGROUND

While opioid analgesics are often necessary for the management of acute postoperative pain, appropriate prescribing practices are crucial to avoid harm. The aim was to investigate the changes in the proportion of people receiving initial opioid prescriptions after hospital discharge following colectomy, and describe trends and patterns in prescription characteristics.

METHODS

This was a retrospective cohort study. Patients undergoing colectomy in England between 2010 and 2019 were included using electronic health record data from linked primary (Clinical Practice Research Datalink Aurum) and secondary (Hospital Episode Statistics) care. The proportion of patients having an initial opioid prescription issued in primary care within 90 days of hospital discharge was calculated. Prescription characteristics of opioid type and formulation were described.

RESULTS

Of 95 155 individuals undergoing colectomy, 15 503 (16.3%) received opioid prescriptions. There was a downward trend in the proportion of patients with no prior opioid exposure (opioid naive) who had a postdischarge opioid prescription (P <0.001), from 11.4% in 2010 to 6.7% in 2019 (-41.3%, P <0.001), whereas the proportions remained stable for those prescribed opioids prior to surgery, from 57.5% in 2010 to 58.3% in 2019 (P = 0.637). Codeine represented 44.5% of all prescriptions and prescribing increased by 14.5% between 2010 and 2019. Prescriptions for morphine and oxycodone rose significantly by 76.6% and 31.0% respectively, while tramadol prescribing dropped by 48.0%. The most commonly prescribed opioid formulations were immediate release (83.9%), followed by modified release (5.8%) and transdermal (3.2%). There was a modest decrease in the prescribing of immediate-release formulations from 86.0% in 2010 to 82.0% in 2019 (P <0.001).

CONCLUSION

Over the 10 years studied, there was a changing pattern of opioid prescribing following colectomy, with a decrease in the proportion of opioid-naive patients prescribed postdischarge opioids.

Acute Pain and Development of Opioid Use Disorder: Patient Risk Factors

PURPOSE OF REVIEW

Pharmacological therapy for acute pain carries the risk of opioid misuse, with opioid use disorder (OUD) reaching epidemic proportions worldwide in recent years. This narrative review covers the latest research on patient risk factors for opioid misuse in the treatment of acute pain. In particular, we emphasize newer findings and evidence-based strategies to reduce the prevalence of OUD.

RECENT FINDINGS

This narrative review captures a subset of recent advances in the field targeting the literature on patients' risk factors for OUD in the treatment for acute pain. Besides well-recognized risk factors such as younger age, male sex, lower socioeconomic status, White race, psychiatric comorbidities, and prior substance use, additional challenges such as COVID-19 further aggravated the opioid crisis due to associated stress, unemployment, loneliness, or depression. To reduce OUD, providers should evaluate both the individual patient's risk factors and preferences for adequate timing and dosing of opioid prescriptions. Short-term prescription should be considered and patients at-risk closely monitored. The integration of non-opioid analgesics and regional anesthesia to create multimodal, personalized analgesic plans is important. In the management of acute pain, routine prescription of long-acting opioids should be avoided, with implementation of a close monitoring and cessation plan.

Opioid Analgesics after Bariatric Surgery: A Scoping Review to Evaluate Physiological Risk Factors for Opioid-Related Harm

The persisting use of opioids following bariatric surgery has emerged as a prevalent complication, heightening the probability of opioid-related harm (ORM), such as opioid-related fatalities and prescription opioid use disorder (OUD). A comprehensive review of PubMed literature from 1990 to 2023 was conducted to pinpoint physiological influences on postoperative ORM. As a result, we found that patients undertaking bariatric operations often exhibit an inherently higher risk for substance use disorders, likely attributable to genetic predisposition and related neurobiological changes that engender obesity and addiction-like tendencies. Furthermore, chronic pain is a common post-bariatric surgery complaint, and the surgical type impacts opioid needs, with increased long-term opioid use after surgeries. Additionally, the subjective nature of pain perception in patients with obesity can distort pain reporting and the corresponding opioid prescription both before and after surgery. Furthermore, the postoperative alterations to the gastrointestinal structure can affect the microbiome and opioid absorption rates, resulting in fluctuating systemic exposure to orally ingested opioids. The prospect of ORM development post-bariatric surgery appears amplified due to a preexisting susceptibility to addictive habits, surgically induced pain, modified gut-brain interaction and pain management and the changed pharmacokinetics post-surgery. Further research is warranted to clarify these potential risk variables for ORM, specifically OUD, in the bariatric population.

Cigarette smoking, opioid consumption, and pain intensity after major surgery: An observational study

BACKGROUND

Chronic exposure to nicotine may change pain perception and promote opioid intake. This study aimed to evaluate the putative effect of cigarette smoking on opioid requirements and pain intensity after surgery.

METHODS

Patients who underwent major surgery and received intravenous patient-controlled analgesia (IV-PCA) at a medical center between January 2020 and March 2022 were enrolled. Patients' preoperative smoking status was assessed using a questionnaire by certified nurse anesthetists. The primary outcome was postoperative opioid consumption within 3 days after surgery. The secondary outcome was the mean daily maximum pain score, assessed using a self-report 11-point numeric rating scale, and the number of IV-PCA infusion requests within three postoperative days. Multivariable linear regression models were used to calculate the regression coefficient (beta) and 95% confidence interval (CI) for the association between smoking status and outcomes of interest.

RESULTS

A total of 1162 consecutive patients were categorized into never smokers (n = 968), former smokers (n = 45), and current smokers (n = 149). Current smoking was significantly associated with greater postoperative opioid consumption (beta: 0.296; 95% CI, 0.068-0.523), higher pain scores (beta: 0.087; 95% CI, 0.009-0.166), and more infusion requests (beta: 0.391; 95% CI, 0.073-0.710) compared with never smokers. In a dose-dependent manner, smoking quantity (cigarette per day) was positively correlated with both intraoperative (Spearman's rho: 0.2207, p = 0.007) and postoperative opioid consumption (Spearman's rho: 0.1745, p = 0.033) among current smokers.

CONCLUSION

Current cigarette smokers experienced higher acute pain, had more IV-PCA infusion requests, and consumed more opioids after surgery. Multimodal analgesia with nonopioid analgesics and opioid-sparing techniques, along with smoking cessation should be considered for this population.

Phenotype- and species-specific skin proteomic signatures for incision-induced pain in humans and mice

BACKGROUND

Acute pain after surgery is common and often leads to chronic post-surgical pain, but neither treatment nor prevention is currently sufficient. We hypothesised that specific protein networks (protein-protein interactions) are relevant for pain after surgery in humans and mice.

METHODS

Standardised surgical incisions were performed in male human volunteers and male mice. Quantitative and qualitative sensory phenotyping were combined with unbiased quantitative mass spectrometry-based proteomics and protein network theory. The primary outcomes were skin protein signature changes in humans and phenotype-specific protein-protein interaction analysis 24 h after incision. Secondary outcomes were interspecies comparison of protein regulation as well as protein-protein interactions after incision and validation of selected proteins in human skin by immunofluorescence.

RESULTS

Skin biopsies in 21 human volunteers revealed 119/1569 regulated proteins 24 h after incision. Protein-protein interaction analysis delineated remarkable differences between subjects with small (low responders, n=12) and large incision-related hyperalgesic areas (high responders, n=7), a phenotype most predictive of developing chronic post-surgical pain. Whereas low responders predominantly showed an anti-inflammatory protein signature, high responders exhibited signatures associated with a distinct proteolytic environment and persistent inflammation. Compared to humans, skin biopsies in mice habored even more regulated proteins (435/1871) 24 h after incision with limited overlap between species as assessed by proteome dynamics and PPI. Immunohistochemistry confirmed the expression of high priority candidates in human skin biopsies.

CONCLUSIONS

Proteome profiling of human skin after incision revealed protein-protein interactions correlated with pain and hyperalgesia, which may be of potential significance for preventing chronic post-surgical pain. Importantly, protein-protein interactions were differentially modulated in mice compared to humans opening new avenues for successful translational research.

Assessment of glyceride-structured oleogels as an injectable extended-release delivery system of bupivacaine

This manuscript systematically assesses three different glycerides (tripalmitin, glyceryl monostearate, and a blend of mono-, di- and triesters of palmitic and stearic acids (Geleol™)) as potential gelator structuring agents of medium-chain triglyceride oil to form an oleogel-based injectable long-acting local anesthetic formulation for postoperative pain management. Drug release testing, oil-binding capacity, injection forces, x-ray diffraction, differential scanning calorimetry, and rheological testing were serially performed to characterize the functional properties of each oleogel. After benchtop assessment, the superior bupivacaine-loaded oleogel formulation was compared to bupivacaine HCl, liposomal bupivacaine, and bupivacaine-loaded medium-chain triglyceride oil in a rat sciatic nerve block model to assess in vivo long-acting local anesthetic performance. In vitro drug release kinetics were similar for all formulations, indicating that drug release rate is primarily dependent on the drug's affinity to the base oil. Glyceryl monostearate-based formulations had superior shelf-life and thermal stability. The glyceryl monostearate oleogel formulation was selected for in vivo evaluation. It was found to have a significantly longer duration of anesthetic effect than liposomal bupivacaine and was able to provide anesthesia twice as long as the equipotent bupivacaine-loaded medium-chain triglyceride oil, indicating that the increased viscosity of the oleogel provided enhanced controlled release over the drug-loaded oil alone.

Molecular identification of bulbospinal ON neurons by GPER, which drives pain and morphine tolerance

The rostral ventromedial medulla (RVM) exerts bidirectional descending modulation of pain attributable to the activity of electrophysiologically identified pronociceptive ON and antinociceptive OFF neurons. Here, we report that GABAergic ON neurons specifically express G protein-coupled estrogen receptor (GPER). GPER+ neurons exhibited characteristic ON-like responses upon peripheral nociceptive stimulation. Optogenetic activation of GPER+ neurons facilitated, but their ablation abrogated, pain. Furthermore, activation of GPER caused depolarization of ON cells, potentiated pain, and ameliorated morphine analgesia through desensitizing μ-type opioid receptor-mediated (MOR-mediated) activation of potassium currents. In contrast, genetic ablation or pharmacological blockade of GPER attenuated pain, enhanced morphine analgesia, and delayed the development of morphine tolerance in diverse preclinical pain models. Our data strongly indicate that GPER is a marker for GABAergic ON cells and illuminate the mechanisms underlying hormonal regulation of pain and analgesia, thus highlighting GPER as a promising target for the treatment of pain and opioid tolerance.

Impact of completion thyroidectomy on postoperative recovery in patients with differentiated thyroid cancer

While an increasing number of patients now undergo lobectomy for low-risk differentiated thyroid cancer, a subset of patients require completion thyroidectomy to facilitate radioactive iodine therapy. Completion thyroidectomy is generally as safe as the initial operation, but a previous study showed that a longer hospitalization is required for completion thyroidectomy. In this study, we reviewed 61 consecutive patients who had been treated with an initial lobectomy and subsequent completion thyroidectomy at our institution from 2012 to 2021. We detected a changepoint in 2016 for the proportion of patients who were treated with a thyroid lobectomy (Pettitt's test P = 0.049). The rate of completion thyroidectomy remained stable throughout the study period. There was no difference in operating time, intraoperative blood loss, perioperative drop in calcium levels, and postoperative hospital stay between surgeries. The patients reported higher pain scores on the day of operation (P = 0.007) and the postoperative day 1 (P = 0.022). Occult papillary microcarcinomas were identified in the contralateral thyroid lobe in 13 (21%) patients. Multifocality was the only predictor for residual malignancy in multivariate regression. In conclusion, patients with differentiated thyroid cancer experienced more pain in the immediate postoperative period following completion thyroidectomy. Hospital stays do not change with appropriate opioid-free pain control.

The negative impact of opioids on cancer patients treated with immune checkpoint inhibitors: a systematic review and meta-analysis

PURPOSE

As one of the most effective analgesics, opioids are essential for patients with cancer-related pain, even in the context of the opioid abuse crisis. The current meta-analysis aimed to identify whether concomitant exposure to opioids can affect the efficacy of ICIs and lead to a worse prognosis.

METHODS

PubMed, Embase, and the Cochrane Library were searched based on the PRISMA checklist, through April 2022, for the following terms: ("opioids" OR "concomitant medication") AND ("Neoplasm" OR "Carcinoma" OR "Cancer" OR "Tumor") AND ("Immunotherapy" OR "Immune Checkpoint Inhibitor" OR "PD-L1 Inhibitor" OR "PD-1 Inhibitor" OR "CTLA-4 Inhibitor"). The outcomes considered were overall survival (OS) and progression-free survival (PFS) calculated using the random-effects or fixed-effects model.

RESULTS

After screening 531 studies, a total of 7 articles involving 2690 patients were eligible for quantitative analysis. The use of opioids was negatively correlated with OS (HR 1.75, 95%CI 1.32-2.31, P < 0.001; I² = 81%, P < 0.001) and significantly reduced the PFS (HR 1.61, 95%CI 1.41-1.83, P < 0.001; I² = 0%, P = 0.63) of patients treated with ICIs. Similar results were obtained in each subgroup analysis. While NSAIDs could lead to poor OS (HR 1.25, 95% CI 1.03-1.51, P = 0.02; I² = 0%, P = 0.60) but not PFS (HR 1.11, 95% CI = 0.89-1.39, P = 0.36) for ICIs patients. And sensitivity analyses confirmed the reliability of the results.

CONCLUSION

Opioids significantly reduced OS and PFS in patients receiving ICI therapy. Thus, the use of different types of opioids should be considered with caution, and it is necessary to actively develop alternative treatments.

Dynamics of Acute Postsurgical Pain over the Last Decade: A Bibliometric Analysis

OBJECTIVE

Minimizing acute postsurgical pain (APSP) remains a challenge, despite extensive research about it. This study comprehensively analyzed the literature on APSP to assess how the field has developed and where it may go in the future.

METHODS

Studies on APSP indexed in the Web of Science Core Collection and published from 2012 to 2021 were assessed for eligibility. Data from included studies were analyzed using CiteSpace, Python, and Microsoft.

RESULTS

Analysis of 5,236 publications on APSP showed that the number of articles per year has increased linearly. The United States leads other countries in terms of the number and centrality of publications. Cocitation analysis suggests that the field focused earlier on the incidence and risk factors of APSP, shifting later to a focus on the reduction and management of adverse outcomes due to APSP. The top-ranked keyword cluster during the study period was "short-term outcomes" (#0), followed by "risk factors" (#1). The strongest burst occurred for the keyword "combination," followed by "multimodal analgesia." The most recent burst occurred for the keywords "regional analgesia," "opioid use," "erector spinae plane block," and "infiltration."

CONCLUSIONS

Hotspots in APSP research since 2012 have been incidence, risk factors, and control of negative outcomes. Future research is likely to concentrate on the use of opioids and technological innovations in regional anesthesia. Our findings may help APSP researchers and clinicians understand their field, optimize clinical practice, and plan future research.

A prospective cohort study to evaluate continuous wound infusion with local analgesics within an enhanced recovery protocol after colorectal cancer surgery

AIM

To reduce detrimental opioid-related side effects, minimising the postoperative opioid consumption is needed, especially in older patients. Continuous wound infusion (CWI) with local analgesics appears to be an effective opioid-sparing alternative. However, the added value of CWI to an enhanced recovery protocol after colorectal cancer (CRC) surgery is unclear. The aim of this study was to evaluate the outcomes of CWI after CRC surgery within a strictly adhered to enhanced recovery protocol.

METHODS

In this multicentre prospective observational cohort study, patients who underwent CRC surgery between May 2019 and January 2021 were included. Patients were treated with CWI as adjunct to multimodal pain management within an enhanced recovery protocol. Postoperative opioid consumption, pain scores and outcomes regarding functional recovery were evaluated.

RESULTS

A cohort of 130 consecutive patients were included, of whom 36.2% were ≥75 years. Postoperative opioids were consumed by 80 (61.5%) patients on postoperative day 0, and by 28 (21.5%), 27 (20.8%), and 18 (13.8%) patients on postoperative days 1, 2, and 3, respectively. Median pain scores were <4 on all days. The median time until first passage of stool was 1.0 (IQR: 1.0-2.0) day. Postoperative delirium occurred in 0.8%. Median length of hospital stay was 3.0 days (IQR: 2.0-5.0).

CONCLUSION

In patients treated with CWI, low amounts of postoperative opioid consumption, adequate postoperative pain control, and enhanced recovery were observed. CWI seems a beneficial opioid-sparing alternative and may further improve the outcomes of an enhanced recovery protocol after CRC surgery, which seems especially valuable for older patients.

Incidence, risk factors, prevention and treatment of postmastectomy pain syndrome in breast cancer: A multicenter study

BACKGROUND

Postmastectomy pain syndrome (PMPS) is a common postoperative condition after breast cancer surgery.

PURPOSE

The aim of this study was to investigate the incidence rate and risk factors of PMPS, and to propose prevention and treatment methods.

METHODS

The study included 1790 postoperative breast cancer patients from three hospitals from 2017 to 2021, of which 302 (13.0%) patients with PMPS were included in the study.

RESULTS

Age, breast surgery type, axillary surgery type and radiotherapy are the risk factors of PMPS. Age, radiotherapy and chemotherapy affect the pain degree of PMPS during movement.

CONCLUSIONS

For breast cancer patients with high risk factors, pain should be actively prevented during perioperative period. Oral pharmacological agents, multidisciplinary combination therapy, local anesthetics and regional anesthesia are the most common treatment of PMPS.

No place for routine use of modified-release opioids in postoperative pain management

Modified-release opioid tablets were introduced into surgical practice in the belief that they provided superior pain relief and reduced nursing workload, and they rapidly became embedded into many perioperative pathways. Although national and international guidelines for the management of postoperative pain now advise against the use of modified-release opioids, they continue to be prescribed in many centres. Recognition that modified-release opioids show lack of benefit and increased risk of harm compared with immediate-release opioids in the acute, postoperative setting has become clear. Their slow onset and offset make rapid and safe titration of these opioids impossible, including down-titration as the patient recovers; pain relief may be less effective; they have been associated with an increased incidence of opioid-related adverse drug events, increased length of hospital stay, and higher readmission rates; and they lead to higher rates of opioid-induced ventilatory impairment and persistent postoperative opioid use. Evidence indicates that modified-release opioids should not be used routinely in the postoperative period.

Patient-controlled intravenous analgesia with opioids after thoracoscopic lung surgery: a randomized clinical trial

Background

Opioids remain the mainstream therapy for post-surgical pain. The choice of opioids administered by patient-controlled intravenous analgesia (PCIA) for thoracoscopic lung surgery is unclear. This study compared 3 opioid analgesics for achieving satisfactory analgesia with minimal emesis (SAME).

Methods

This randomized clinical trial enrolled patients scheduled for thoracoscopic lung surgery randomized to receive 1 of 3 opioids for PCIA: oxycodone (group O), hydromorphone (group H), and sufentanil (group S). The primary outcome was the proportion of subjects achieving SAME, i.e., no-to-mild pain (pain score < 4/10) with minimal nausea/vomiting (PONV score < 2/4) when coughing during the pulmonary rehabilitation exercise in the first 3 postoperative days.

Results

Of 555 enrolled patients, 184 patients in group O, 186 in group H and 184 in group S were included in the final analysis. The primary outcome of SAME was significantly different among group O, H and S (41.3% vs 40.3% vs 29.9%, P = 0.043), but no difference was observed between pairwise group comparisons. Patients in groups O and H had lower pain scores when coughing on the second day after surgery than those in group S, both with mean differences of 1 (3(3,4) and 3(3,4) vs 4(3,4), P = 0.009 and 0.039, respectively). The PONV scores were comparable between three groups (P > 0.05). There were no differences in other opioid-related side effects, patient satisfaction score, and QoR-15 score among three groups.

Conclusions

Given clinically relevant benefits detected, PCIA with oxycodone or hydromorphone is superior to sufentanil for achieving SAME as a supplement to multimodal analgesia in patients undergoing thoracoscopic lung surgery.

Trial registration

This study was registered at (ChiCTR2100045614, 19/04/2021).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-022-01785-4.

Misappropriation of the 1986 WHO analgesic ladder: the pitfalls of labelling opioids as weak or strong

Opioids have a vital role in alleviating pain from cancer and surgery. Despite good intentions, it is now recognised that the original WHO Cancer Pain Relief guidance from 1986, in which opioids were classified as either weak or strong, has been both inadvertently and purposefully misused, thereby contributing to harm from opioid use and misuse. However, the recommendation in the 2018 update of the WHO analgesic ladder that a combination of a high-potency opioid with simple analgesics is better than alternative analgesics for the maintenance of pain relief is also applicable to patients who require short-term opioids. Furthermore, because potential harm through opioid use and misuse is intrinsic to all opioids, whether weak or strong, we argue that the arbitrary classification of opioids either as weak or strong should be discontinued, as this description is not helpful to either prescribers or consumers.