Postoperative pain-from mechanisms to treatment

Present and Future of Pharmacological Management for Acute Moderate-to-Severe Postoperative, Traumatic, or Musculoskeletal Pain in Europe: A Narrative Review

Acute moderate-to-severe pain is common after surgery, trauma, or musculoskeletal injury, but its management remains suboptimal. Current single-agent treatments are limited by safety concerns, narrow therapeutic windows, and abuse potential, leaving substantial unmet needs. Here, we aimed to review guidelines for the management of acute moderate-to-severe post-surgical, trauma-related, or musculoskeletal pain in adults and discuss existing and potential future analgesics in this setting. We searched PubMed to identify relevant guidelines and existing analgesics for acute pain. To identify compounds in development, we searched ClinicalTrials.gov and the European Union Clinical Trials Register. Guidelines universally recognize the limitations of single-agent analgesics (particularly those with a single mechanism of action [MoA]) and recommend a multimodal approach as an established standard for acute pain. The benefit-risk profiles of traditional treatments, including paracetamol (acetaminophen), nonsteroidal anti-inflammatory drugs, selective cyclooxygenase-2 inhibitors, and opioids, can be improved by combining agents targeting different pain pathways. In multimodal approaches, lower doses of constituent agents can be used to achieve the same or superior analgesic effects relative to the individual agents. In some cases, novel formulations and co-crystal technology offer enhanced physicochemical and pharmacokinetic properties over individual agents. Lastly, initiatives to increase patient awareness and education around pain management may improve treatment satisfaction and quality of life, and hasten recovery. In conclusion, management of acute moderate-to-severe pain remains inadequate. Multimodal analgesics may offer advantages over traditional single-agent treatments (that often have a single MoA) for acute moderate-to-severe post-surgical, trauma-related, or musculoskeletal pain in adults. Multimodal analgesics, combined with patient education initiatives and non-pharmacological measures, when necessary, offer promise in addressing unmet needs in this setting.

10-Day Theta Burst Stimulation Intervention Facilitates the Clinical Rehabilitation of Patients After an Isolated Limb Fracture: A Longitudinal SHAM-Controlled Pilot Study

OBJECTIVE

We investigated if theta burst stimulation could enhance recovery by reducing key symptoms when implemented acutely postfracture in participants with an isolated upper limb fracture.

METHODS/DESIGN

This was a pilot study with a randomized matched pair, sham-controlled, participant-blind design of a 10-day prolonged continuous theta burst stimulation protocol. Two main groups were included: I) participants with isolated upper limb fracture receiving active theta burst stimulation and II) patients with isolated upper limb fracture receiving SHAM/placebo. Another group (III) of healthy individuals was the reference group. Disability and pain intensity were collected through questionnaires (disabilities of the Arm, Shoulder, and Hand as well as numerical rating scale (NRA)) at three time points (baseline; 72 hrs after intervention, 3 mos after injury). Group III completed the baseline assessment.

RESULTS

Seventy-nine participants were enrolled. Individuals in the ACTIVE and SHAM groups had similar baseline measures. For disability, the interaction between intervention and time approached significance (F = 2.33; P = 0.11), whereas it was significant for pain (F = 3.42; P = 0.04). At 3 mos after injury, the ACTIVE group reported reduced disability (F = 4.71; P = 0.04) and pain (F = 5.84; P = 0.02) at 3 mos after injury compared to the SHAM group, with clinical measures from ACTIVE group being like controls.

CONCLUSIONS

In isolated upper limb fracture patients, a 10-day theta burst stimulation intervention implemented acutely posttrauma had beneficial effects on symptoms of functional recovery and pain at 3 mos after trauma.

Effect of individualized anesthesia and analgesia on postoperative pain in patients stratified for pain sensitivity: A study protocol for the PeriOPerative individualization trial randomized controlled trial

BACKGROUND

Despite advancements in surgical and anesthesia techniques, acute and persistent postoperative pain are still a common challenge. Postoperative pain has direct effects on individual patient care and outcome, as well as putting strain on limited health care resources. Several prediction methods for postoperative pain have been described. One such method is the assessment of pain during peripheral venous cannulation (VCP). It is not known if different approaches to anesthesia and analgesia, depending on the evaluation of risk for postoperative pain, can improve outcome. The aim of this study is to evaluate if individualized anesthesia and analgesia can affect postoperative pain and recovery after surgery, in patients stratified by VCP.

METHODS

Adult patients scheduled for laparoscopic surgery undergo pain-sensitivity stratification using VCP on the day of surgery. Patients scoring VCP ≥2.0 on the visual analogue scale (pain-sensitive) are randomized to multimodal anaesthesia and analgesia with opioids or standard of care. Patients scoring VCP ≤1.9 (pain-tolerant) are randomized to opioid-free anaesthesia or standard of care. The primary outcome is acute postoperative pain measured with numeric rating scale in the postoperative care unit. Secondary outcomes include analysis of pain after 24 h, persistent postoperative pain and quality of recovery.

DISCUSSION

Individualized perioperative pain management has the potential to improve patient care. This study will examine the impact of different anesthesia and analgesia regimes, in patients with differing pain sensitivity, on postoperative pain.

TRIAL REGISTRATION

Prospectively posted at ClinicalTrials.gov, identifier NCT04751812.

Incidence and risk factors of pain following breast cancer surgery: a retrospective national inpatient sample database study

BACKGROUND

Postoperative pain (PP) is a dynamic process that reflects the complex interplay between symptoms, treatment, and patient experiences, and its intensity is reportedly primarily related to the severity of surgical trauma. However, no large-scale national database-based study has hitherto been conducted to assess the occurrence and features related to PP following breast cancer (BC) surgery.

METHODS

In this retrospective analysis, we screened BC surgery cases between 2015 and 2019 within the National Inpatient Sample (NIS) Database, utilizing the International Classification of Diseases (ICD) 10th edition clinical modification codes. The researchers identified patients who developed PP and compared them to those who did not. Factors associated with PP were then screened: patient demographics (age and race), hospital characteristics (type of insurance, bed size, teaching status, type of admission, location, and hospital area), length of stay (LOS), total cost during hospitalization, inpatient mortality, comorbidities, and perioperative complications. Data were analyzed using descriptive statistics. Multivariate logistic regression analysis was used to determine the independent risk factors for postoperative pain in BC surgery.

RESULTS

39,870 BC surgery cases were identified over a five-year period from 2015 to 2019. The overall occurrence of PP following breast cancer surgery was 6.15% (2,387 cases), with a slight upward trend every year. Significant racial disparities were observed, Whites associated with a higher incidence of PP (P < 0.001). In addition, the incidence of elective admission was 11.96% lower (67.491% vs. 79.451%) than that of patients without PP following breast cancer surgery (P < 0.001). Besides, PP was related to prolonged hospitalization duration (3 vs. 2 days; P < 0.001), and higher total cost ($68,283 vs. $60,036; P < 0.001). Multivariate logistic regression identified breast cancer surgery-independent risk factors for PP, including younger age, non-elective hospital admission, rural hospitals, depression, drug abuse, metastatic cancer, psychoses, weight loss, and chronic pulmonary disease. In addition, postoperative pain for BC was associated with urinary retention, gastrointestinal complications, continuous invasive ventilation, deep vein thrombosis, urinary tract infection, blood transfusion, arrhythmia, and chest pain.

CONCLUSION

Despite the low incidence of postoperative pain in BC surgery cases, it is essential to investigate factors predisposing to PP to allow optimal care management and improve the outcomes of this patient population.

Nerve Blocks for Post-Surgical Pain Management: A Narrative Review of Current Research

Opioids remain the mainstay of post-surgical pain management; however, concerns regarding addiction and side effects necessitate the exploration of alternatives. This narrative review highlights the potential of nerve blocks as a safe and effective strategy for post-surgical pain control. This review explores the use of various nerve block techniques tailored to specific surgical procedures. These include nerve blocks for abdominal surgeries; fascial plane blocks for chest surgeries; nerve blocks for arm surgeries; and nerve blocks for lower limb surgery including; femoral, hip, and knee surgeries. By targeting specific nerves, these blocks can provide targeted pain relief without the negative side effects associated with opioids. Emerging evidence suggests that nerve blocks can be as effective as opioids in managing pain, while potentially offering additional benefits such as faster recovery, improved patient satisfaction, and reduced reliance on opioids. However, the effectiveness of nerve blocks varies depending on type of surgery, and in individual patients. Rebound pain, which temporary increase in pain after a block wears off, can occur. In addition, some techniques require specialized guidance for accurate placement. In conclusion, nerve blocks show great promise as effective alternatives for managing post-surgical pain. They can reduce the need for opioids and their side effects, leading to better patient outcomes and satisfaction. Future studies should assess the long-term impacts of specific nerve blocks on mortality rates, cost-effectiveness, and their incorporation into multimodal pain management approaches to further enhance post-surgical care.

Pronociceptive role of spinal Cav2.3 (R-type) calcium channels in a mouse model of postoperative pain

BACKGROUND

More than 80% of patients may experience acute pain after a surgical procedure, and this is often refractory to pharmacological intervention. The identification of new targets to treat postoperative pain is necessary. There is an association of polymorphisms in the Cav2.3 gene with postoperative pain and opioid consumption. Our study aimed to identify Cav2.3 as a potential target to treat postoperative pain and to reduce opioid-related side effects.

EXPERIMENTAL APPROACH

A plantar incision model was established in adult male and female C57BL/6 mice. Cav2.3 expression was detected by qPCR and suppressed by siRNA treatment. The antinociceptive efficacy and safety of a Cav2.3 blocker-alone or together with morphine-was also assessed after surgery.

KEY RESULTS

Paw incision in female and male mice caused acute nociception and increased Cav2.3 mRNA expression in the spinal cord but not in the incised tissue. Intrathecal treatment with siRNA against Cav2.3, but not with a scrambled siRNA, prevented the development of surgery-induced nociception in both male and female mice, with female mice experiencing long-lasting effects. High doses of i.t. SNX-482, a Cav2.3 channel blocker, or morphine injected alone, reversed postoperative nociception but also induced side effects. A combination of lower doses of morphine and SNX-482 mediated a long-lasting reversal of postsurgical pain in female and male mice.

CONCLUSION

Our results demonstrate that Cav2.3 has a pronociceptive role in the induction of postoperative pain, indicating that it is a potential target for the development of therapeutic approaches for the treatment of postoperative pain.

Current concepts and targets for preventing the transition of acute to chronic postsurgical pain

PURPOSE OF REVIEW

It is estimated that approximately a third of patients undergoing certain surgeries may report some degree of persistent pain postoperatively. Chronic postsurgical pain (CPSP) reduces quality of life, is challenging to treat, and has significant socio-economic impact.

RECENT FINDINGS

From an epidemiological perspective, factors that predispose patients to the development of CPSP may be considered in relation to the patient, the procedure or, the care environment. Prevention or management of transition from acute to chronic pain often need a multidisciplinary approach beginning early in the preoperative period and continuing beyond surgical admission. The current concepts regarding the role of central and peripheral nervous systems in chronification of pain may provide targets for future therapies but, the current evidence seems to suggest that a multimodal analgesic approach of preventive analgesia along with a continued follow-up and treatment after hospital discharge may hold the key to identify and manage the transitioning of acute to chronic pain.

SUMMARY

A comprehensive multidisciplinary approach with prior identification of risk factors, minimizing the surgical insult and a culture of utilizing multimodal analgesia and continued surveillance beyond the period of hospitalization is an important step towards reducing the development of chronic pain. A transitional pain service model may accomplish many of these goals.

A single-center retrospective chart review of percutaneous PNS for treatment of chronic shoulder pain

Objective

The present IRB-approved retrospective chart review describes the use of a 60-day PNS treatment for shoulder pain at a single center in 60 total consecutive patients.

Background

Chronic shoulder pain affects an increasing number of patients per year and is especially prevalent in elderly populations. Percutaneous peripheral nerve stimulation (PNS) treatment targeting the nerves of the shoulder has been shown to reduce pain in prospective clinical studies and in analysis of real-world data.

Methods

Data were extracted from the electronic medical records of patients who had previously undergone percutaneous PNS treatment for chronic shoulder pain. Demographic data and treatment characteristics were summarized alongside treatment outcomes.

Results

Overall, 84 % (49/58) of patients reported substantial (≥50 %) pain relief at the end-of-treatment. The records for 2 patients did not include patient-reported percent pain relief. The average indwelling period for leads (i.e., treatment period) was 57 days. Findings on treatment effectiveness were consistent when the patient population was stratified by cause of pain, duration living with pain, and presence of pain-modifying comorbidities. Stimulation paradigms were identified and categorized by the nerve target and stimulation frequency (e.g., motor stimulation, sensory stimulation, or bimodal stimulation).

Conclusions

These results indicate percutaneous PNS is an effective treatment for patients with various shoulder pain histories, and while all stimulation paradigms were effective at reducing pain, patients who received bimodal PNS reported the greatest pain relief. Key limitations of the study included heterogeneous shoulder pain etiologies among patients and sparse availability of long-term follow-up data. These data support existing real-world and prospective clinical evidence on the efficacy of 60-day PNS treatment at treating chronic pain and provide valuable insights into its use in clinical practice.

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.

Real-world evidence of durable multi-dimensional improvement after 60-day peripheral nerve stimulation treatment used for shoulder pain

Aim: This real-world analysis aims to quantify improvements in multiple health domains in patients who received 60-day peripheral nerve stimulation (PNS) for shoulder pain.Materials & methods: Patients reported percent pain relief and Patient Global Impression of Change in quality of life, physical function and sleep at the end of treatment (EOT), 3 months, and 6 months.Results: Of 768 patients, 80.7% were responders in at least one domain at EOT. In a subset who were followed up, a cumulative 75% continued to respond in at least one domain through 6 months (85% [n = 140/165] at 3 months and 88% [n = 53/60] at 6 months).Conclusion: 60-day PNS used for shoulder pain produced multi-dimensional improvements across health domains at EOT and through 6 months.

Analgesic Effect of Sulforaphane: A New Application for Poloxamer-Hyaluronic Acid Hydrogels

Sulforaphane (SFN) has shown potential as an antioxidant and anti-inflammatory agent. To improve its druggability, we developed new analgesic formulations with sulforaphane-loaded hyaluronic acid (HA)-poloxamer (PL) hydrogel. This study evaluated the pre-clinical safety and effectiveness of these formulations. Effectiveness was tested on Wistar rats divided into groups (n = 15) receiving (IM, 10 mg/kg) SFN formulations or control groups (without SFN). This study used a hind paw incision postoperative pain model to evaluate mechanical hypersensitivity with von Frey filaments. TNF-α, IL-1β, substance P, and CGRP levels verified anti-inflammatory activity in the hind paw tissue. Histopathology of tissues surrounding the injection site was assessed after 2 and 7 days post-treatment. To corroborate drug safety, cell viability of 3T3 and RAW 264.7 cultures was assessed. Additionally, RAW 264.7 cultures primed with carrageenan evaluated nitric oxide (NO) levels. All animals exhibited post-incisional hypersensitivity, and F2 (PL 407/338 (18/2%) + HA 1% + SFN 0.1%) showed a longer analgesic effect (p < 0.05). F2 reduced TNF-α, IL-1β, and CGRP levels (p < 0.05). Histopathological evaluation showed mild to moderate inflammatory reactions after the formulations' injections. F2 produced no significant difference in cell viability (p > 0.05) but reduced NO production (p < 0.05). Thus, our results highlight the biocompatibility and effectiveness of F2.

Cannabinoid Analgesia in Postoperative Pain Management: From Molecular Mechanisms to Clinical Reality

Postoperative pain (POP) is a challenging clinical phenomenon that affects the majority of surgical patients and demands effective management to mitigate adverse outcomes such as persistent pain. The primary goal of POP management is to alleviate suffering and facilitate a seamless return to normal function for the patient. Despite compelling evidence of its drawbacks, opioid analgesia remains the basis of POP treatment. Novel therapeutic approaches rely on multimodal analgesia, integrating different pharmacological strategies to optimize efficacy while minimizing adverse effects. The recognition of the imperative role of the endocannabinoid system in pain regulation has prompted the investigation of cannabinoid compounds as a new therapeutic avenue. Cannabinoids may serve as adjuvants, enhancing the analgesic effects of other drugs and potentially replacing or at least reducing the dependence on other long-term analgesics in pain management. This narrative review succinctly summarizes pertinent information on the molecular mechanisms, clinical therapeutic benefits, and considerations associated with the plausible use of various cannabinoid compounds in treating POP. According to the available evidence, cannabinoid compounds modulate specific molecular mechanisms intimately involved in POP. However, only two of the eleven clinical trials that evaluated the efficacy of different cannabinoid interventions showed positive results.

Functional recovery of wrist surgery with regional versus general anesthesia: a prospective observational study

PURPOSE

Regional anesthesia may favour postoperative rehabilitation by inhibiting peripheral sensitization and secondary hyperalgesia. The literature on this subject is limited. In the present FUNCTION study, we sought to compare the functional recovery post orthopedic wrist surgery with regional versus general anesthesia.

METHODS

We conducted a single-centre prospective observational cohort study in adult patients with a distal radial fracture. Functional recovery was assessed with validated psychometrics questionnaires (Quick Disabilities of Arm, Shoulder and Hand [QuickDASH] and Patient-Rated Wrist Evaluation [PRWE]), range of motion, and grip strength. We used a linear mixed regression model to assess the impact of the anesthesia technique on functional recovery. Postoperative pain and patient satisfaction were evaluated using a visual analog scale.

RESULTS

We recruited 76 patients. At 12 weeks post surgery, there was no difference between the type of anesthesia and functional recovery with the QuickDASH (higher scores worse; regional anesthesia [RA], 22.7 vs general anesthesia [GA], 19.3; adjusted mean difference [aMD], -0.3; 95% confidence interval [CI], -9.6 to 9.0; P = 0.9) and PRWE (higher scores worse; RA group, 21.0 vs GA group, 20.5; aMD, -3.3; 95% CI, -12.1 to 5.6; P = 0.93) questionnaires. Range of motion, satisfaction, and postoperative pain were similar between groups. Right-hand grip strength was higher in the GA group.

CONCLUSION

Regional anesthesia was not associated with improved functional recovery compared with general anesthesia. The dominance of the operated limb was a confusion factor in all evaluation modalities. Further research taking into account the dominance of the hand is necessary to establish the effects of regional anesthesia on functional recovery.

STUDY REGISTRATION

ClinicalTrials.gov (NCT04541745); registered 9 September 2020.

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.

Venom-inspired somatostatin receptor 4 (SSTR4) agonists as new drug leads for peripheral pain conditions

Persistent pain affects one in five people worldwide, often with severely debilitating consequences. Current treatment options, which can be effective for mild or acute pain, are ill-suited for moderate-to-severe persistent pain, resulting in an urgent need for new therapeutics. In recent years, the somatostatin receptor 4 (SSTR 4 ), which is expressed in sensory neurons of the peripheral nervous system, has emerged as a promising target for pain relief. However, the presence of several closely related receptors with similar ligand-binding surfaces complicates the design of receptor-specific agonists. In this study, we report the discovery of a potent and selective SSTR 4 peptide, consomatin Fj1, derived from extensive venom gene datasets from marine cone snails. Consomatin Fj1 is a mimetic of the endogenous hormone somatostatin and contains a minimized binding motif that provides stability and drives peptide selectivity. Peripheral administration of synthetic consomatin Fj1 provided analgesia in mouse models of postoperative and neuropathic pain. Using structure-activity studies, we designed and functionally evaluated several Fj1 analogs, resulting in compounds with improved potency and selectivity. Our findings present a novel avenue for addressing persistent pain through the design of venom-inspired SSTR 4 -selective pain therapeutics.

One Sentence Summary

Venom peptides from predatory marine mollusks provide new leads for treating peripheral pain conditions through a non-opioid target.

[Opioid-free anesthesia : Wrong track or meaningful exit from the era of opioid-based analgesia?]

The limitations and disadvantages of opioids in anesthesia are very well known but the advantages combined with a lack of effective alternatives even now still prevents refraining from using opioids as part of an adequate pain therapy. For decades, pain research has had the declared goal of replacing opioids with new substances which have no serious side effects; however, currently this goal seems to be a long way off. Due to the media coverage of the "opioid crisis" in North America, the use of opioids for pain management is also increasingly being questioned by the patients. Measures to contain this crisis are only slowly taking effect in view of the increasing number of deaths, which is why the triggers are still being sought. The perioperative administration of opioids is not only a possible gateway to addiction and abuse but it can also cause outcome-relevant complications, such as respiratory depression, postoperative nausea and vomiting and an increase in postoperative pain. Therefore, these considerations gave rise to the idea of an opioid-free anesthesia (OFA), i.e., opioids are not administered as part of anesthesia to carry out surgical procedures. Although this idea may make sense at first glance, a rapid introduction of this concept appears to be risky as it entails significant changes for the entire anesthesiological management. Based on relatively robust data from clinical studies, this concept can now be evaluated and discussed not only emotionally but also objectively. This review article presents arguments for or against the complete avoidance of intraoperative or even perioperative opioids. The current conditions in Germany are primarily taken into account, so that the perioperative pain therapy is transferable to the established standards. The results from current clinical studies on the implementation of an opioid-free anesthesia are summarized and discussed.

The New Orientation of Postoperative Analgesia: Remote Ischemic Preconditioning

Purpose of Review

Postoperative analgesia is currently a significant topic in anesthesiology. Currently, the predominant approach for achieving multimodal analgesia involves the utilization of pharmacotherapy and regional anesthesia procedures. The primary objectives of this approach are to mitigate postoperative pain, enhance patient satisfaction, and diminish overall opioid usage. Nevertheless, there is a scarcity of research on the use of remote ischemia preconditioning aimed at mitigating postoperative pain.

Recent Findings

Transient stoppage of blood flow to an organ has been found to elicit remote ischemia preconditioning (RIPC), which serves as a potent intrinsic mechanism for protecting numerous organs. In addition to its established role in protecting against reperfusion injury, RIPC has recently been identified as having potential benefits in the context of postoperative analgesia.

Summary

In addition to traditional perioperative analgesia, RIPC provides perioperative analgesia and organ protection.

Involvement of peripheral mast cells in a fibromyalgia model in mice

Fibromyalgia is a painful disorder of unknown aetiology that presents activation and recruitment of innate immune cells, including mast cells. Efforts have been made to understand its pathogenesis to manage it better. Thus, we explored the involvement of peripheral mast cells in an experimental model of fibromyalgia induced by reserpine. Reserpine (1 mg/kg) was subcutaneously (s.c.) injected once daily in the back of male Swiss mice for three consecutive days. We analysed mechanical and cold allodynia, muscle fatigue and number of mast cell in plantar tissue. The fibromyalgia induction produced mast cell infiltration (i.e., mastocytosis) in the mice's plantar tissue. The depletion of mast cell mediators with the compound 48/80 (0.5-4 mg/kg, intraperitoneal (i.p.)) or the mast cell membrane stabilizer ketotifen fumarate (10 mg/kg, oral route (p.o.) widely (80-90 %) and extensively (from 1 up to 10 days) prevented reserpine-induced mechanical and cold allodynia and muscle fatigue. Compound 48/80 also prevented the reserpine-induced mastocytosis. Finally, we demonstrated that PAR-2, 5-HT2A, 5-HT3, H1, NK1 and MrgprB2 receptors, expressed in neuronal or mast cells, seem crucial to mediate fibromyalgia-related cardinal symptoms since antagonists or inhibitors of these receptors (gabexate (10 mg/kg, s.c.), ENMD-1068 (10 mg/kg, i.p.), ketanserin (1 mg/kg, i.p.), ondansetron (1 mg/kg, p.o.), promethazine (1 mg/kg, i.p.), and L733,060 (5 mg/kg, s.c.), respectively) transiently reversed the reserpine-induced allodynia and fatigue. The results indicate that mast cells mediate painful and fatigue behaviours in this fibromyalgia model, representing potential therapy targets to treat fibromyalgia syndrome.

Co-crystal of Tramadol-Celecoxib Versus Tramadol or Placebo for Acute Moderate-to-Severe Pain After Oral Surgery: Randomized, Double-Blind, Phase 3 Trial (STARDOM1)

INTRODUCTION

Co-crystal of tramadol-celecoxib (CTC) is the first analgesic co-crystal for acute pain. This completed phase 3 multicenter, double-blind trial assessed the efficacy and safety/tolerability of CTC in comparison with that of tramadol in the setting of moderate-to-severe pain up to 72 h after elective third molar extraction requiring bone removal.

METHODS

Adults (n = 726) were assigned randomly to five groups (2:2:2:2:1): orally administered twice-daily CTC 100 mg (44 mg rac-tramadol hydrochloride/56 mg celecoxib; n = 164), 150 mg (66/84 mg; n = 160) or 200 mg (88/112 mg; n = 160); tramadol 100 mg four times daily (n = 159); or placebo four times daily (n = 83). Participants in CTC groups also received twice-daily placebo. The full analysis set included all participants who underwent randomization. The primary endpoint was the sum of pain intensity differences over 0 to 4 h (SPID0-4; visual analog scale). Key secondary endpoints included 4-h 50% responder and rescue medication use rates. Safety endpoints included adverse events (AEs), laboratory measures, and Opioid-Related Symptom Distress Scale (OR-SDS) score.

RESULTS

All CTC doses were superior to placebo (P < 0.001) for primary and key secondary endpoints. All were superior to tramadol for SPID0-4 (analysis of covariance least squares mean differences [95% confidence interval]: - 37.1 [- 56.5, - 17.6], - 40.2 [- 59.7, - 20.6], and - 41.7 [- 61.2, - 22.2] for 100, 150, and 200 mg CTC, respectively; P < 0.001) and 4-h 50% responder rate. Four-hour 50% responder rates were 32.9% (CTC 100 mg), 33.8% (CTC 150 mg), 40.6% (CTC 200 mg), 20.1% (tramadol), and 7.2% (placebo). Rescue medication use was lower in the 100-mg (P = 0.013) and 200-mg (P = 0.003) CTC groups versus tramadol group. AE incidence and OR-SDS scores were highest for tramadol alone.

CONCLUSIONS

CTC demonstrated superior pain relief compared with tramadol or placebo, as well as an improved benefit/risk profile versus tramadol.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT02982161; EudraCT number, 2016-000592-24.

Movement-evoked Pain versus Pain at Rest in Postsurgical Clinical Trials and in Meta-analyses: An Updated Systematic Review

BACKGROUND

Given the widespread recognition that postsurgical movement-evoked pain is generally more intense, and more functionally relevant, than pain at rest, the authors conducted an update to a previous 2011 review to re-evaluate the assessment of pain at rest and movement-evoked pain in more recent postsurgical analgesic clinical trials.

METHODS

The authors searched MEDLINE and Embase for postsurgical pain randomized controlled trials and meta-analyses published between 2014 and 2023 in the setting of thoracotomy, knee arthroplasty, and hysterectomy using methods consistent with the original 2011 review. Included trials and meta-analyses were characterized according to whether they acknowledged the distinction between pain at rest and movement-evoked pain and whether they included pain at rest and/or movement-evoked pain as a pain outcome. For trials measuring movement-evoked pain, pain-evoking maneuvers used to assess movement-evoked pain were tabulated.

RESULTS

Among the 944 included trials, 504 (53%) did not measure movement-evoked pain (vs. 61% in 2011), and 428 (45%) did not distinguish between pain at rest and movement-evoked pain when defining the pain outcome (vs. 52% in 2011). Among the 439 trials that measured movement-evoked pain, selection of pain-evoking maneuver was highly variable and, notably, was not even described in 139 (32%) trials (vs. 38% in 2011). Among the 186 included meta-analyses, 94 (51%) did not distinguish between pain at rest and movement-evoked pain (vs. 71% in 2011).

CONCLUSIONS

This updated review demonstrates a persistent limited proportion of trials including movement-evoked pain as a pain outcome, a substantial proportion of trials failing to distinguish between pain at rest and movement-evoked pain, and a lack of consistency in the use of pain-evoking maneuvers for movement-evoked pain assessment. Future postsurgical trials need to (1) use common terminology surrounding pain at rest and movement-evoked pain, (2) assess movement-evoked pain in virtually every trial if not contraindicated, and (3) standardize movement-evoked pain assessment with common, procedure-specific pain-evoking maneuvers. More widespread knowledge translation and mobilization are required in order to disseminate this message to current and future investigators.

EDITOR’S PERSPECTIVE

Comparison of postoperative pain between transoral and conventional thyroidectomy: a propensity score-matched analysis

BACKGROUND

The extent of postoperative pain following transoral thyroidectomy is not well-understood and remains a subject of debate. This study aims to analyze and compare postoperative pain levels between patients undergoing transoral and conventional transcervical thyroidectomy.

METHODS

A prospective evaluation on postoperative pain was conducted in 310 patients undergoing conventional thyroidectomy and 194 undergoing transoral thyroidectomy. Pain levels were evaluated using the numerical rating scale (NRS, ranging from 0 to 10) through preoperative and postoperative questionnaires at specified time points: 1, 3, and 6 days, and 1 and 3 months following surgery. Propensity score-matched analysis was carried out based on six covariates: sex, age, body mass index, extent of thyroidectomy, tumor size, and central neck dissection.

RESULTS

After propensity score matching based on the six covariates, 121 patient pairs were identified from each group. Within this matched cohort, postoperative pain scores significantly worsened 1 day after surgery but showed progressive recovery up to 3 months post-surgery in both groups. The transoral group exhibited higher postoperative pain scores than the conventional group from day 1 (4.43 ± 2.6 vs. 3.11 ± 2.5, p < 0.001) to day 6 (1.76 ± 1.9 vs. 1.13 ± 1.6, p = 0.016) post-surgery, with no significant difference noted at 1 month. Among transoral procedures, pain scores were significantly higher for the endoscopic approach compared to the robotic approach on days 1 (5.52 ± 2.3 vs. 4.29 ± 2.3, p = 0.028) and 3 (3.52 ± 2.5 vs. 2.64 ± 2.0, p = 0.047) post-surgery.

CONCLUSIONS

Postoperative pain was significantly higher in transoral thyroidectomy compared to conventional thyroidectomy up to 6 days post-surgery. Within the transoral group, the robotic procedure resulted in lower pain levels than the endoscopic approach during the early postoperative period.

The Effect of Preoperative Marijuana Use on Surgical Outcomes, Patient-Reported Outcomes, and Opioid Consumption Following Lumbar Fusion

STUDY DESIGN

Retrospective Cohort Study.

OBJECTIVES

To (1) investigate the effect of marijuana use on surgical outcomes following lumbar fusion, (2) determine how marijuana use affects patient-reported outcomes measures (PROMs), and (3) determine if marijuana use impacts the quantity of opioids prescribed.

METHODS

Patients > 18 years of age who underwent primary one- or two-level lumbar fusion with preoperative marijuana use at our institution were identified. A 3:1 propensity match incorporating patient demographics and procedure type was conducted to compare preoperative marijuana users to non-marijuana users. Patient demographics, surgical characteristics, surgical outcomes (90-day all-cause and 90-day surgical readmissions, reoperations, and revision surgeries), pre- and postoperative narcotic usage, and PROMs were compared between groups. Multivariate regression models were created to determine the effect of marijuana on surgical reoperations patient-reported outcomes (PROMs) 1-year postoperatively.

RESULTS

Of the 259 included patients, 65 used marijuana preoperatively. Multivariate logistic regression analysis demonstrated that marijuana use (OR = 2.28, P = .041) significantly increased the likelihood of having a spine reoperation. No other surgical outcome was found to be significantly different between groups. Multivariate linear regression analysis showed that marijuana use was not significantly associated with changes in 1-year postoperative PROMs (all, P > .05). The quantity of pre- and postoperative opioids prescriptions was not significantly different between groups (all, P > .05).

CONCLUSIONS

Preoperative marijuana use increased the likelihood of a spine reoperation for any indication following lumbar fusion, but it was not associated with 90-day all cause readmission, surgical readmission, the magnitude of improvement in PROMs, or differences in opioid consumption.

LEVEL OF EVIDENCE

III.

Possibility of Using Surgical Pleth Index in Predicting Postoperative Pain in Patients after Vitrectomy Performed under General Anesthesia

Adequacy of anesthesia concept (AoA) in the guidance of general anesthesia (GA) is based on entropy, and it also reflects the actual depth of anesthesia and the surgical pleth index (SPI). Therefore, this study aimed to analyze the potential existence of relationships between SPI values at certain stages of the AoA-guided GA for vitreoretinal surgeries (VRS) and the incidence of intolerable postoperative pain perception (IPPP). A total of 175 patients were each assigned to one of five groups. In the first, the VRS procedure was performed under GA without premedication; in the second group, patients received metamizole before GA; in the third, patients received acetaminophen before GA; in the fourth group, patients received Alcaine before GA; and, in the peribulbar block group, the patients received a peribulbar block with a mix of the solutions of lignocaine and bupivacaine. Between the patients declaring mild and statistically significant differences in the IPPP in terms of SPI values before induction (52.3 ± 18.8 vs. 63.9 ± 18.1, p < 0.05) and after emergence from GA (51.1 ± 13 vs. 68.1 ± 8.8; p < 0.001), it was observed that the patients postoperatively correlated with heart rate variations despite the group allocation. The current study proves the feasibility that preoperative SPI values help with predicting IPPP immediately after VRS under AoA guidance and discrimination (between mild diagnoses and IPPP when based on postoperative SPI values) as they correlate with heart rate variations. Specifically, this applies when the countermeasures of IPPP and hemodynamic fluctuations are understood to be of importance in reducing unwelcome adverse events.

Prediction of pain using electrocardiographic-derived autonomic measures: A systematic review

BACKGROUND AND OBJECTIVE

Pain is a major clinical challenge, and understanding the pathophysiology is critical for optimal management. The autonomic nervous system reacts to pain stimuli, and autonomic dysfunction may predict pain sensation. The most used assessment of autonomic function is based on electrocardiographic measures, and the ability of such measures to predict pain was investigated.

DATABASES AND DATA TREATMENT

English articles indexed in PubMed and EMBASE were reviewed for eligibility and included when they reported electrocardiographic-derived measures' ability to predict pain response. The quality in prognostic studies (QUIPS) tool was used to assess the quality of the included articles.

RESULTS

The search revealed 15 publications, five on experimental pain, five on postoperative pain, and five on longitudinal clinical pain changes, investigating a total of 1069 patients. All studies used electrocardiographically derived parameters to predict pain assessed with pain thresholds using quantitative sensory testing or different scales. Across all study modalities, electrocardiographic measures were able to predict pain. Higher parasympathetic activity predicted decreased experimental, postoperative, and long-term pain in most cases while changes in sympathetic activity did not consistently predict pain.

CONCLUSIONS

Most studies demonstrated that parasympathetic activity could predict acute and chronic pain intensity. In the clinic, this may be used to identify which patients need more intensive care to prevent, for example postoperative pain and develop personalized chronic pain management.

SIGNIFICANCE

Pain is a debilitating problem, and the ability to predict occurrence and severity would be a useful clinical tool. Basal autonomic tone has been suggested to influence pain perception. This systematic review investigated electrocardiographic-derived autonomic tone and found that increased parasympathetic tone could predict pain reduction in different types of pain.

Postoperative Patient Pain Severity and Its Association With Anxiety, Depression, and Sleep Quality

Introduction The experience of pain is a complex phenomenon. A patient in the acute postsurgical pain setting may feel a constant bombardment of nociceptive input from the surgical site; this in turn influences psychological factors that determine the overall emotional experience of pain, which is significant. The aim of our study was to investigate the severity of pain in postsurgical patients three days after surgery using the 100 mm visual analog scale (VAS). Methods This was a cross-sectional assessment of postoperative pain. Participants were patients between 18 and 64 years of age who had undergone a surgical procedure (laparoscopic or open surgery), three days prior to the data collection and who were admitted or discharged postoperatively at the Al Salmaniya Complex, Manama, Bahrain. Participants were asked demographic questions about whether they had laparoscopic or open surgeries and completed self-reporting scales. Patient Health Questionnaire-9 (PHQ-9) was utilized to screen for both the presence and severity of depression; Generalized Anxiety Disorder 7-item (GAD-7) was administered to screen for anxiety; the Insomnia Severity Index (ISI) was used to evaluate insomnia; and the VAS was used to evaluate pain.  Results Sixty-seven patients were recruited, with a mean age of 61.53 years (SD = 7.37). Twenty-nine (43%) were females, 38 (57%) were males, 36 (54%) underwent elective surgery, 31 (46%) underwent emergency surgery, 31 (46%) underwent laparoscopic surgery, and 36 (54%) underwent open surgery. The average score on the Brief Pain Inventory Short Form (BPISF) was 8.12 (SD = 1.16), indicating a moderate level of pain. Twenty-six (43%) patients had moderate-severe insomnia, 21 participants (31%) had no insomnia, 17 participants (25%) had subthreshold insomnia, 28 (42%) had moderate depression, five (7%) had moderate-severe depression, and 34 (51%) had severe depression. Eighteen participants (27%) had mild anxiety, 46 (69%) had moderate anxiety, and 3 (4%) had severe anxiety. Six of the participants (9%) reported moderate pain, while 61 participants (91%) reported severe pain.

β-Caryophyllene Inhibits Monoacylglycerol Lipase Activity and Increases 2-Arachidonoyl Glycerol Levels In Vivo: A New Mechanism of Endocannabinoid-Mediated Analgesia?

The mechanisms of β-caryophyllene (BCP)-induced analgesia are not well studied. Here, we tested the efficacy of BCP in an acute postsurgical pain model and evaluated its effect on the endocannabinoid system. Rats were treated with vehicle and 10, 25, 50, and 75 mg/kg BCP. Paw withdrawal responses to mechanical stimuli were evaluated using an electronic von Frey anesthesiometer. Endocannabinoids, including 2-arachidonoylglycerol (2-AG), were also evaluated in plasma and tissues using high-performance liquid chromatography-tandem mass spectrometry. Monoacylglycerol lipase (MAGL) activity was evaluated in vitro as well as ex vivo. We observed a dose-dependent and time-dependent alleviation of hyperalgesia in incised paws up to 85% of the baseline value at 30 minutes after administration of BCP. We also observed dose-dependent increases in the 2-AG levels of about threefold after administration of BCP as compared with vehicle controls. Incubations of spinal cord tissue homogenates from BCP-treated rats with isotope-labeled 2-arachidonoylglycerol-d8 revealed a reduced formation of the isotope-labeled MAGL product 2-AG-d8 as compared with vehicle controls, indicating MAGL enzyme inhibition. In vitro MAGL enzyme activity assessment using 2-AG as the substrate revealed an IC50 of 15.8 µM for MAGL inhibition using BCP. These data showed that BCP inhibits MAGL activity in vitro and in vivo, causing 2-AG levels to rise. Since the endocannabinoid 2-AG is a CB1 and CB2 receptor agonist, we propose that 2-AG-mediated cannabinoid receptor activation contributes to BCP's mechanism of analgesia. SIGNIFICANCE STATEMENT: β-Caryophyllene (BCP) consumption is relatively safe and is approved by the Food and Drug Administration as a flavoring agent, which can be used in cosmetic and food additives. BCP is a potent anti-inflammatory agent that showed substantial antihyperalgesic properties in this study of acute pain suggesting that BCP might be an alternative to opioids. This study shows an additive mechanism (monoacylglycerol lipase inhibition) by which BCP might indirectly alter CB1 and CB2 receptor activity and exhibit its pharmacological properties.

Spinal GABA transporter 1 contributes to evoked-pain related behavior but not resting pain after incision injury

The inhibitory function of GABA at the spinal level and its central modulation in the brain are essential for pain perception. However, in post-surgical pain, the exact mechanism and modes of action of GABAergic transmission have been poorly studied. This work aimed to investigate GABA synthesis and uptake in the incisional pain model in a time-dependent manner. Here, we combined assays for mechanical and heat stimuli-induced withdrawal reflexes with video-based assessments and assays for non-evoked (NEP, guarding of affected hind paw) and movement-evoked (MEP, gait pattern) pain-related behaviors in a plantar incision model in male rats to phenotype the effects of the inhibition of the GABA transporter (GAT-1), using a specific antagonist (NO711). Further, we determined the expression profile of spinal dorsal horn GAT-1 and glutamate decarboxylase 65/67 (GAD65/67) by protein expression analyses at four time points post-incision. Four hours after incision, we detected an evoked pain phenotype (mechanical, heat and movement), which transiently ameliorated dose-dependently following spinal inhibition of GAT-1. However, the NEP-phenotype was not affected. Four hours after incision, GAT-1 expression was significantly increased, whereas GAD67 expression was significantly reduced. Our data suggest that GAT-1 plays a role in balancing spinal GABAergic signaling in the spinal dorsal horn shortly after incision, resulting in the evoked pain phenotype. Increased GAT-1 expression leads to increased GABA uptake from the synaptic cleft and reduces tonic GABAergic inhibition at the post-synapse. Inhibition of GAT-1 transiently reversed this imbalance and ameliorated the evoked pain phenotype.

[New Approaches in Perioperative Algesimetry]

The measurement of anaesthetic depth and muscle relaxation have been routine procedures during general anaesthesia for years. Quantification of intraoperative nociception, on the other hand, is still largely impossible. Various methods have been tested and commercialised for more than 10 years. However, a real breakthrough has not yet been achieved and the routine application of all methods available so far is not without problems. This article explains methodological similarities, but also points to specific aspects of various commercial solutions for perioperative algesimetry.

Comprehensive quantitative sensory testing shows altered sensory function in women with chronic pelvic pain: results from the Translational Research in Pelvic Pain (TRiPP) Study

ABSTRACT

Chronic pelvic pain (CPP), despite its high prevalence, is still relatively poorly understood mechanistically. This study, as part of the Translational Research in Pelvic Pain (TRiPP) project, has used a full quantitative sensory testing (QST) paradigm to profile n = 85 women with and without CPP (endometriosis or bladder pain specifically). We used the foot as a control site and abdomen as the test site. Across 5 diagnostically determined subgroups, we found features which are common across different aetiologies, eg, gain of function in pressure pain threshold (PPT) when assessing responses from the lower abdomen or pelvis (referred pain site). However, disease-specific phenotypes were also identified, eg, greater mechanical allodynia in endometriosis, despite there being large heterogeneities within diagnostic groups. The most common QST sensory phenotype was mechanical hyperalgesia (>50% across all the groups). A "healthy' sensory phenotype was seen in <7% of CPP participants. Specific QST measures correlated with sensory symptoms assessed by the painDETECT questionnaire (pressure-evoked pain [painDETECT] and PPT [QST] [ r = 0.47, P < 0.001]; mechanical hyperalgesia (painDETECT) and mechanical pain sensitivity [MPS from QST] [ r = 0.38, P = 0.009]). The data suggest that participants with CPP are sensitive to both deep tissue and cutaneous inputs, suggesting that central mechanisms may be important in this cohort. We also see phenotypes such as thermal hyperalgesia, which may be the result of peripheral mechanisms, such as irritable nociceptors. This highlights the importance of stratifying patients into clinically meaningful phenotypes, which may have implications for the development of better therapeutic strategies for CPP.

Predictors of post-discharge pain and satisfaction with pain management after laparoscopic bariatric surgery: a prospective cohort study

BACKGROUND

Pain management after bariatric surgery remains challenging given the risk for analgesia-related adverse events (e.g., opioid use disorder, marginal ulcers). Identifying modifiable factors associated with patient-reported pain outcomes may improve quality of care. We evaluated the extent to which patient and procedural factors predict 7-day post-discharge pain intensity, pain interference, and satisfaction with pain management after bariatric surgery.

METHODS

This prospective cohort study included adults undergoing laparoscopic bariatric surgery at two university-affiliated hospitals and one private clinic. Preoperative assessments included demographics, Pain Catastrophizing Scale (score range 0-52), Patient Activation Measure (low [< 55.1] vs. high [≥ 55.1]), pain expectation (0-10), and Patient-Reported Outcomes Measurement Information System-29 (PROMIS-29) anxiety and depression scales. At 7 days post-discharge, assessments included PROMIS-29 pain intensity (0-10) and pain interference scales (41.6-75.6), and satisfaction with pain management (high [10-9] vs. lower [8-0]). Linear and logistic regression were used to assess the association of pain outcomes with potential predictors.

RESULTS

Three hundred and fifty-one patients were included (mean age = 44 ± 11 years, BMI = 45 ± 8 kg/m2, 77% female, 71% sleeve gastrectomy). At 7 days post-discharge, median (IQR) patient-reported pain intensity was 2.5 (1-5), pain interference was 55.6 (52.0-61.2), and 76% of patients reported high satisfaction with pain management. Pain intensity was predicted by preoperative anxiety (β + 0.04 [95% CI + 0.01 to + 0.07]) and pain expectation (+ 0.15 [+ 0.05 to + 0.25]). Pain interference was predicted by preoperative anxiety (+ 0.22 [+ 0.11 to + 0.33]), pain expectation (+ 0.47 [+ 0.10 to + 0.84]), and age (- 0.09 [- 0.174 to - 0.003]). Lower satisfaction was predicted by low patient activation (OR 1.94 [1.05-3.58]), higher pain catastrophizing (1.03 [1.003-1.05]), 30-day complications (3.27 [1.14-9.38]), and age (0.97 [0.948-0.998]).

CONCLUSION

Patient-related factors are important predictors of post-discharge pain outcomes after bariatric surgery. Our findings highlight the value of addressing educational, psychological, and coping strategies to improve postoperative pain outcomes.

Pain in Colorectal Surgery: How Does It Occur and What Tools Do We Have for Treatment?

Pain is a complex entity with deleterious effects on the entire organism. Poorly controlled postoperative pain impacts the patient outcome, being associated with increased morbidity, inadequate quality of life and functional recovery. In the current surgical environment with less invasive surgical procedures increasingly being used and a trend towards rapid discharge home after surgery, we need to continuously re-evaluate analgesic strategies. We have performed a narrative review consisting of a description of the acute surgical pain anatomic pathways and the connection between pain and the surgical stress response followed by reviewing methods of multimodal analgesia in colorectal surgery found in recent literature data. We have described various regional analgesia techniques and drugs effective in pain treatment, emphasizing their advantages and concerns. We have also tried to identify present knowledge gaps requiring future research. Our review concludes that surgical pain has peculiarities that make its management complex, implying a consistent, multimodal approach aiming to block both peripheral and central pain pathways.

Evaluating patient outcomes in postoperative pain management according to the revised American Pain Society Patient Outcome Questionnaire (APS-POQ-R)

BACKGROUND

In the first 24 h after surgery, it is necessary to evaluate the patient responses to pain, analgesia and patient satisfaction to prevent complications related to the pain management process.

AIM

To evaluate patients' outcomes (pain qualities, side effects of the pain management, pain treatment satisfaction, non-pharmacological pain treatment methods, predictors of pain management satisfaction and percentage of pain relief) according to the Revised American Pain Society Patient Outcome Questionnaire (APS-POQ-R) in the first 24 h.

DESIGN

Cross-sectional study.

METHODS

The study sample was comprised of 700 patients, who were surgically treated at the surgical clinics of a university hospital and completed the first postoperative 24 h. The data was collected through the "Patient Information Form" and the "Turkish version of the revised American Pain Society Patient Outcome Questionnaire (APS-POQ-R)".

RESULTS

The medians of the lowest and the worst postoperative pain severity level were 3.0 and 7.0, respectively. Patients experienced severe pain in 60 % of the first postoperative 24 h and reported that 70 % of their pain eventually decreased. A positive and significant correlation was found between pain interference, pain-affected mood/emotions, the severity of pain-related side effects, the least and worst pain severity levels and severe pain, and the percentage of time experienced with severe pain.

CONCLUSIONS

Most of the patients experienced severe pain, which restricted their daily life activities and led to negative emotions. Acute postoperative pain may negatively affect patient outcomes and delay postoperative recovery during the early period. Therefore, pain should be managed in the early period to prevent physical and psychological side effects.

Prognostic models for chronic postsurgical pain-Current developments, trends, and challenges

PURPOSE OF REVIEW

Prognostic models for chronic postsurgical pain (CPSP) aim to predict the likelihood for development and severity of CPSP in individual patients undergoing surgical procedures. Such models might provide valuable information for healthcare providers, allowing them to identify patients at higher risk and implement targeted interventions to prevent or manage CPSP effectively. This review discusses the latest developments of prognostic models for CPSP, their challenges, limitations, and future directions.

RECENT FINDINGS

Numerous studies have been conducted aiming to develop prognostic models for CPSP using various perioperative factors. These include patient-related factors like demographic variables, preexisting pain conditions, psychosocial aspects, procedure-specific characteristics, perioperative analgesic strategies, postoperative complications and, as indicated most recently, biomarkers. Model generation, however, varies and performance and accuracy differ between prognostic models for several reasons and validation of models is rather scarce.

SUMMARY

Precise methodology of prognostic model development needs advancements in the field of CPSP. Development of more accurate, validated and refined models in large-scale cohorts is needed to improve reliability and applicability in clinical practice and validation studies are necessary to further refine and improve the performance of prognostic models for CPSP.

Postoperative acute pain management with duloxetine as compared to placebo: A systematic review with meta-analysis of randomized clinical trials

BACKGROUND

Duloxetine has been used as an adjunct in multimodal analgesia for acute postoperative pain in clinical studies. This meta-analysis aims to conclude whether oral duloxetine, when given perioperatively, is any better than a placebo in managing postoperative pain. Effects of duloxetine on postoperative pain scores, time to first rescue analgesia, postoperative rescue analgesia consumption, side effects attributable to duloxetine, and patient satisfaction profile were assessed.

METHOD

MEDLINE, Web of Science, EMBASE, Scholar Google, and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched with keywords including "Duloxetine" AND "postoperative pain", "Duloxetine" AND "acute pain" and with "Duloxetine" till October 2022. This meta-analysis included randomized clinical trials in which perioperative duloxetine 60 mg per oral was administered not more than 7 days before surgery and for at least 24 after surgery but not more than 14 days after surgery. All RCTs in which the comparator is placebo and outcomes related to analgesic efficacy like pain scores, opioid consumption, and side effects of duloxetine until 48 h postoperatively were included. Data were extracted from the studies and a risk of bias summary was formed using the Cochrane Collaboration tool. Effect sizes were given as standardized mean differences for continuous outcomes and risk ratios (RR) by the Mantel-Haenszel test for the categorical outcome. Confirmation of publication bias was done by Egger's regression test (p < 0.05). If publication bias or heterogeneity was detected, the trim-and-fill method was used to calculate the adjusted effect size. Sensitivity analysis was done by leaving one out method after excluding the study with a high risk of bias. Subgroup analysis was done based on the type of surgery and gender. The study was prospectively registered in the PROSPERO under the registration number CRD42019139559.

FINDINGS

29 studies with 2043 patients met the inclusion criteria and were reviewed for this meta-analysis. Postoperative pain scores at 24 h [Std. Mean Difference (95% CI); -0.69 (-1.07, -0.32)] and at 48 h [-1.13 (-1.68, -0.58)] are significantly less with duloxetine (p-value < 0.05). Time to first rescue analgesia was significantly more in patients where duloxetine was administered [1.27 (1.10, 1.45); p-value > 0.05]. Opioid consumption up to 24 h [-1.82 (-2.46, -1.18)] and 48 h [-2.48 (-3.46, -1.50)] was significantly less (p-value < 0.05) in patients who received duloxetine. Complications and recovery profiles were similar in patients receiving either duloxetine or a placebo.

INTERPRETATION

Based on GRADE findings, we conclude that there is low to moderate evidence to advocate the use of duloxetine for managing postoperative pain. Further trials are needed to replicate or refute these results based on robust methodology.

Tramadol for chronic pain in adults: protocol for a systematic review with meta-analysis and trial sequential analysis of randomised clinical trials

BACKGROUND

Chronic pain in adults is a frequent clinical symptom with a significant impact on patient well-being. Therefore, sufficient pain management is of utmost importance. While tramadol is a commonly used pain medication, the quality of evidence supporting its use has been questioned considering the observed adverse events. Our objective will be to assess the benefits and harms of tramadol compared with placebo or no intervention for chronic pain.

METHODS/DESIGN

We will conduct a systematic review of randomised clinical trials with meta-analysis and trial sequential analysis to assess the beneficial and harmful effects of tramadol in any dose, formulation, or duration. We will accept placebo or no intervention as control interventions. We will include adult participants with any type of chronic pain, including cancer-related pain. We will systematically search the Cochrane Library, MEDLINE, EMBASE, Science Citation Index, and BIOSIS for relevant literature. We will follow the recommendations by Cochrane and the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement. The risk of systematic errors ('bias') and random errors ('play of chance') will be assessed. The certainty of evidence will be evaluated using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

DISCUSSION

Although tramadol is often being used to manage chronic pain conditions, the beneficial and harmful effects of this intervention are unknown. The present review will systematically assess the current evidence on the benefits and harms of tramadol versus placebo or no intervention to inform clinical practice and future research.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019140334.

Association between preoperative serum C-reactive protein level and leukocyte count and postoperative pain after otolaryngological surgery

PURPOSE

To determine whether the preoperative inflammatory serum C-reactive protein (CRP) and leukocyte count (LEUK) are associated with postoperative pain and complaints after otolaryngological surgery.

METHODS

Retrospective evaluation of 680 patients (33% female, median age 50 years) receiving otolaryngological surgery between November 2008 and March 2017 in a tertiary university hospital. Postoperative pain on the first postoperative day was assessed using the validated questionnaire of the German-wide project Quality Improvement in Postoperative Pain Treatment (QUIPS) including a numeric rating scale for assessment of postoperative pain (NRS, 0-10). The influence of preoperative parameters including CRP and LEUK on patients' postoperative pain was estimated.

RESULTS

Mean CRP value was 15.6 ± 34.6 mg/l and mean LEUK value 7.8 ± 3.2 Gpt/l. Patients with pharyngeal surgery had the highest CRP values (34.6 ± 52.9 mg/l), highest LEUK values (9.2 ± 4.2 Gpt/l) and the highest pain levels (3.1 ± 2.4 NRS) compared to all other surgical procedures (all p < 0.05). Higher postoperative pain was associated with LEUK values > 11.3 Gpt/l (r = 0.093, p = 0.016) and higher preoperative chronic pain (r = 0.127, p = 0.001). Multivariate analysis confirmed younger age, female gender, duration of surgery, preoperative chronic pain, type of surgery, and higher LEUK values > 11.3 as independent factors for postoperative pain. Perioperative antibiotics had no effect on the postoperative pain.

CONCLUSION

Beyond known factors, preoperative LEUK as inflammation marker is an independent predictor for pain on the first postoperative day.

The effect of acupressure on pain level and hemodynamic parameters after coronary angiography: a randomized controlled study

Background

Subsequent to coronary angiography, procedures performed to prevent bleeding may cause pain in the patient. In this study, we aimed to determine the effect of acupressure on pain level and hemodynamic parameters in patients undergoing coronary angiography.

Method

In this prospective, a two-arm (1:1), randomized controlled trial was conducted, with 124 patients undergoing coronary angiography included. The randomly assigned study group (n = 62) received acupressure on the LI4 (on the dorsum of the hand, between the 1st and 2nd metacarpal bones), PC6 (three fingers above the wrist), and LI11 (at the lateral end of the transverse cubital crease) points for 15 min 2 h after angiography, while the control group (n = 62) received no acupressure. Data were collected using the visual pain scale (VAS) and hemodynamic parameters [systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), respiratory rate (RR), and peripheral oxygen saturation (SpO₂)], monitoring form before, immediately after, and at 10, 20, and 30 min after acupressure.

Results

In the study, it was found that patients had moderate pain after coronary angiography (study group: 5.02 ± 2.27; control group: 3.98 ± 1.82). When the groups were compared, it was found that the VAS score of the study group before angiography was significantly higher than that of the control group, but lower than the control group immediately after acupressure, and at 10, 20, and 30 min after acupressure. In addition, it was determined that acupressure was significantly higher in DBP and RR in the study group compared to the control group at 20 and 30 min; it was not effective in terms of SBP, HR, and SpO₂ values.

Conclusion

The results of the study indicated that patients reported moderate pain after coronary angiography, and that acupressure was effective in reducing the pain level, but affected only the DBP and RR hemodynamic parameters. Since the study was single-centered and followed for a short time, it is recommended to conduct new studies with a longer duration.

The mechanisms and management of persistent postsurgical pain

An estimated 10%-50% of patients undergoing a surgical intervention will develop persistent postsurgical pain (PPP) lasting more than 3 months despite adequate acute pain management and the availability of minimally invasive procedures. The link between early and late pain outcomes for surgical procedures remains unclear-some patients improve while others develop persistent pain. The elective nature of a surgical procedure offers a unique opportunity for prophylactic or early intervention to prevent the development of PPP and improve our understanding of its associated risk factors, such as pre-operative anxiety and the duration of severe acute postoperative pain. Current perioperative pain management strategies often include opioids, but long-term consumption can lead to tolerance, addiction, opioid-induced hyperalgesia, and death. Pre-clinical models provide the opportunity to dissect mechanisms underpinning the transition from acute to chronic, or persistent, postsurgical pain. This review highlights putative mechanisms of PPP, including sensitisation of peripheral sensory neurons, neuroplasticity in the central nervous system and nociceptive signalling along the neuro-immune axis.

Efficacy of a continuous wound infiltration system for postoperative pain management in gynecologic patients who underwent single-port access laparoscopy for adnexal disease

Introduction

Single-port access (SPA) laparoscopy requires only one incision, unlike conventional laparoscopy. However, its umbilical incision is larger than that of conventional laparoscopy and can be vulnerable to postoperative pain. This study aimed to evaluate whether simultaneous use of a continuous wound infiltration (CWI) system and intravenous patient-controlled analgesia (IV PCA) effectively decreases surgical site pain in patients who underwent SPA laparoscopy due to gynecologic adnexal disease.

Methods

A total of 371 patients who underwent SPA laparoscopy and who received IV PCA or CWI was retrospectively reviewed (combined group [CWI + IV PCA, n = 159] vs. PCA group [IV PCA only, n = 212]). To evaluate postoperative pain management, the numeric rating scale (NRS) pain score after surgery, total amount of fentanyl administered via IV PCA, and additional pain killer consumption were collected.

Results

The NRS scores at 12 h (1.90 ± 1.11 vs. 2.70 ± 1.08, p < 0.001) and 24 h (1.82 ± 0.82 vs. 2.11 ± 1.44, p = 0.026) after surgery were significantly lower in the combined group than in the PCA group. The total amount of PCA fentanyl was significantly smaller in the combined group than in the PCA group (p < 0.001). The total quantity of rescue analgesics was smaller in the combined group than in the PCA group (p < 0.05).

Conclusion

Combined use of the CWI system and IV PCA is an effective postoperative pain management strategy in patient who underwent SPA laparoscopy for adnexal disease.

Prolonged continuous wound infusion of local anesthetic and steroid after major abdominal surgery to reduce opioid consumption: a randomized, double-blind trial

BACKGROUND

Continuous wound infusion (CWI) is effective for post-operative pain management, but the effect of prolonged infusions and the use of steroids in the infused mixture have never been addressed. We investigate the effect of prolonged CWI with ropivacaine 0.2% (R) over seven days and methylprednisolone (Mp) 1 mg/kg infused in the wound in the first 24 hours.

METHODS

This is a randomized, double blind, phase III trial (RCT) in major abdominal surgery with laparotomy. After a 24-hours pre-peritoneal CWI of R-Mp, patients were randomized to receive either R-Mp or placebo for the next 24 hours. Then, patient-controlled CWI with only ropivacaine 0.2% or placebo (according to the randomization group) was planned between 48 hours and seven days after surgery. Morphine equivalents at seven days were analyzed, together with any catheter- or drug-related side effect and PPSP at 3 months.

RESULTS

We enrolled 120 patients (63 in the CWI group, 57 in the placebo group). Prolonged CWI did not reduce opioid consumption in the first seven postoperative days (P=0.08). CWI was associated with reduced consumption of non-opioid analgesics (P=0.03). Most of the patients continued to require bolus in the surgical wound beyond 48 hours. PPSP prevalence was not different between groups.

CONCLUSIONS

Prolonged infusion with R-Mp is safe and effective but did not reduce opioid consumption in the seven days after surgery or PPSP prevalence.

Kinins' Contribution to Postoperative Pain in an Experimental Animal Model and Its Implications

Postoperative pain causes discomfort and disability, besides high medical costs. The search for better treatments for this pain is essential to improve recovery and reduce morbidity and risk of chronic postoperative pain. Kinins and their receptors contribute to different painful conditions and are among the main painful inflammatory mediators. We investigated the kinin's role in a postoperative pain model in mice and reviewed data associating kinins with this painful condition. The postoperative pain model was induced by an incision in the mice's paw's skin and fascia with the underlying muscle's elevation. Kinin levels were evaluated by enzyme immunoassays in sham or operated animals. Kinin's role in surgical procedure-associated mechanical allodynia was investigated using systemic or local administration of antagonists of the kinin B₁ receptor (DALBk or SSR240612) or B₂ receptor (Icatibant or FR173657) and a kallikrein inhibitor (aprotinin). Kinin levels increased in mice's serum and plantar tissue after the surgical procedure. All kinin B₁ or B₂ receptor antagonists and aprotinin reduced incision-induced mechanical allodynia. Although controversial, kinins contribute mainly to the initial phase of postoperative pain. The kallikrein-kinin system can be targeted to relieve this pain, but more investigations are necessary, especially associations with other pharmacologic targets.

Transitional Pain Medicine; New Era, New Opportunities, and New Journey

Chronic postsurgical pain (CPSP), also known as persistent postsurgical pain (PPSP), is pain that develops or increases in intensity after a surgical procedure and lasts more than 3 months. Transitional pain medicine is the medical field that focuses on understanding the mechanisms of CPSP and defining risk factors and developing preventive treatments. Unfortunately, one significant challenge is the risk of developing opioid use dependence. Multiple risk factors have been discovered, with the most common, and modifiable, being uncontrolled acute postoperative pain; preoperative anxiety and depression; and preoperative site pain, chronic pain, and opioid use.

Relationship between pain, nerve injury and clinical outcomes after flexor tendon injuries in zones 1-2: a retrospective cohort study

Introduction

The influence of pain and a concomitant digital nerve injury on the course of rehabilitation after flexor tendon injury remains ambiguous. The objectives of the study were to: i) analyse the evolution of pain spanning one year after a primary flexor tendon repair in zones 1-3; ii) examine the differences in pain levels in patients with and without digital nerve injury; and iii) evaluate the relationship between pain, digital nerve injury and pain medication, total active motion (TAM), DASH scores and patient satisfaction.

Methods

Data from 189 patients were retrieved from a flexor tendon registry between 2014 and 2020. Differences in pain, TAM, DASH and patient satisfaction were analysed. Multiple linear and binary logistic regression analyses were performed to determine the relationship between clinical outcomes.

Results

Pain significantly decreased in the course of rehabilitation (p < 0.001 to 0.006). No relationship could be identified between nerve injury and pain (p = 0.21-0.97). In week 6, the presence of pain and a nerve injury were significantly associated with lower TAM scores (p = 0.001). In week 13, pain during motion (p < 0.001) and the presence of a nerve injury (p = 0.036) were significantly associated with worse DASH scores. Patient satisfaction was significantly inversely correlated to pain during motion in weeks 13 and 26 (p < 0.001).

Conclusion

We found a significant relationship between pain during motion and pain medication intake, TAM, DASH scores and patient satisfaction. It is therefore advisable to closely monitor this parameter after flexor tendon injuries.

Study registration

This multi-center cohort study is registered under https://clinicaltrials.gov: NCT04312412.

Modulation of the Inflammatory Response by Pre-emptive Administration of IMT504 Reduces Postoperative Pain in Rats and has Opioid-Sparing Effects

Despite the available knowledge on underlying mechanisms and the development of several therapeutic strategies, optimal management of postoperative pain remains challenging. This preclinical study hypothesizes that, by promoting an anti-inflammatory scenario, pre-emptive administration of IMT504, a noncoding, non-CpG oligodeoxynucleotide with immune modulating properties, will reduce postincisional pain, also facilitating therapeutic opioid-sparing. Male adult Sprague-Dawley rats with unilateral hindpaw skin-muscle incision received pre-emptive (48 and 24 hours prior to surgery) or postoperative (6 hours after surgery) subcutaneous vehicle (saline) or IMT504. Various groups of rats were prepared for pain-like behavior analyses, including subgroups receiving morphine or naloxone, as well as for flow-cytometry or quantitative RT-PCR analyses of the spleen and hindpaws (for analysis of inflammatory phenotype). Compared to vehicle-treated rats, pre-emptive IMT504 significantly reduced mechanical allodynia by 6 hours after surgery, and accelerated recovery of basal responses from 72 hours after surgery and onwards. Cold allodynia was also reduced by IMT504. Postoperative administration of IMT504 resulted in similar positive effects on pain-like behavior. In IMT504-treated rats, 3 mg/kg morphine resulted in comparable blockade of mechanical allodynia as observed in vehicle-treated rats receiving 10 mg/kg morphine. IMT504 significantly increased hindpaw infiltration of mesenchymal stem cells, CD4+T and B cells, and caused upregulated or downregulated transcript expressions of interleukin-10 and interleukin-1β, respectively. Also, IMT504 treatment targeted the spleen, with upregulated or downregulated transcript expressions, 6 hours after incision, of interleukin-10 and interleukin-1β, respectively. Altogether, pre-emptive or postoperative IMT504 provides protection against postincisional pain, through participation of significant immunomodulatory actions, and exhibiting opioid-sparing effects. PERSPECTIVE: This preclinical study introduces the noncoding non-CpG oligodeoxynucleotide IMT504 as a novel modulator of postoperative pain and underlying inflammatory events. The opioid-sparing effects observed for IMT504 appear as a key feature that could contribute, in the future, to reducing opioid-related adverse events in patients undergoing surgical intervention.

Role of neuromodulation in acute pain settings

Peripheral nerve stimulation (PNS), a type of neuromodulatory technique, is increasingly used to treat chronic pain syndromes. PNS has also recently gained popularity as a viable adjunct analgesic modality in acute pain settings, where the practice primarily relies on using boluses or infusion of local anesthetics for nerve blockade, followed by stimulation to extend the analgesia. There is some early promise in PNS for perioperative analgesic control, but considerable obstacles must be addressed before it can be implemented into standard practice. In this daring discourse, we explore the possibilities and constraints of using the PNS paradigm in acute pain.

Effects of ultrasound-guided erector spinae plane block on postoperative acute pain and chronic post-surgical pain in patients underwent video-assisted thoracoscopic lobectomy: a prospective randomized, controlled trial

OBJECTIVE

To investigate the effects of ultrasound-guided erector spinae plane block (ESPB) on acute and chronic post-surgical pain in patients underwent video-assisted thoracoscopic lobectomy.

METHODS

A total of 94 patients, who underwent elective unilateral video-assisted thoracoscopic lobotomy from August 2021 to December 2021 were randomly divided into general anesthesia group (group A, n = 46) and ESPB combined with general anesthesia group (group B, n = 48) by computer. Patient controlled intravenous analgesia(PCIA) was performed in both groups after operation. The numerical rating scale(NRS) of rest and cough pain at post anesthesia care unit(PACU), 2 h, 6 h, 12 h, 24 and 48 h after operation, frequency of PCIA in 24 h after operation, frequency of rescue analgesia, patient satisfaction, adverse reactions and complications were recorded in the two groups. Incidence of chronic pain at 3 months and 6 months after operation, the effect of daily life and rating of chronic pain management measures were recorded in the two groups.

RESULTS

Compared with group A, rest and cough NRS score at 2 h, 6 h, 12 h, 24 and 48 h after surgery, frequency of PCIA use at 24 h after surgery, frequency of rescue analgesia were significantly decreased in group B (P < 0.05). There was no significant difference in NRS scores of rest and cough at PACU after operation between 2 groups after surgery at post anesthesia care unit (P > 0.05). There were no significant differences in the incidence of postoperative chronic pain between the 2 groups(P > 0.05);The effect of postoperative chronic pain on daily life and pain management measures in group B were significantly lower than those in group A(P < 0.05). Compared with group A, patients in group B had higher satisfaction degree, lower incidence of postoperative nausea and vomiting(PONV), and lower incidence of agitation during anesthesia recovery (P < 0.05). There were no pneumothorax, hematoma and toxicity of local anesthetic in the 2 groups.

CONCLUSION

Ultrasound-guided erector spinae plane block can significantly reduce acute post-surgical pain, can not reduce the incidence of chronic post-surgical pain, but can significantly reduce the severity of chronic pain in patients underwent video-assisted thoracoscopic lobectomy.

TRIAL REGISTRATION

ChiCTR2100050313,date of registration:26/08/2021.

Provider-directed analgesia for dental pain

INTRODUCTION

Extraction of impacted molar teeth is a common procedure performed by oral surgeons and general dentists, with postoperative pain being a significant adverse event post-surgery. If mismanaged, pain can lead to complications that impact oral and systemic health. The current scourge of the opioid epidemic has ushered in a new era of provider-directed analgesic (PDA) therapy in dentistry.

AREAS COVERED

This article provides an in-depth review on the major pharmacological and therapeutic properties of established and alternative analgesics used to manage dental pain.

EXPERT OPINION

Substantial evidence-based literature shows combination of a non-steroidal anti-inflammatory drug (NSAID; e.g. ibuprofen) and acetaminophen provides superior pain relief than single-agent or combination opioid regimens. However, there are clinical scenarios (e.g. severe pain) when short-course opioid prescription is appropriate in select patients, in which a 2-3-day treatment duration is typically sufficient. Alternative agents (e.g. caffeine, gabapentin, phytotherapies), typically in combination with established agents, can mitigate postoperative dental pain. Some evidence suggests preemptive therapies (e.g. corticosteroids, NSAIDs) reduce amounts of postsurgical analgesic consumption and might lessen opioid prescription burden. In summary, this comprehensive review provides an opportune update on the evolving landscape of pharmacotherapy for acute postsurgical dental pain, informing best practices for PDA in the dental setting.

The analgesic effect of total intravenous anaesthesia with propofol versus inhalational anaesthesia for acute postoperative pain after hepatectomy: a randomized controlled trial

BACKGROUND

Postoperative pain control can be challenging in patients undergoing hepatectomy. A previous retrospective study on hepatobiliary/ pancreatic surgeries showed better postoperative pain control in patients who received propofol TIVA. The aim of this study was to determine the analgesic effect of propofol TIVA for hepatectomy. This clinical study has been registered at ClinicalTrials.gov (NCT03597997).

METHODS

A prospective randomized controlled trial was performed to compare the analgesic effect of propofol TIVA versus inhalational anaesthesia. Patients aged between 18 and 80 years old with an American Society of Anesthesiologist (ASA) physical status of I-III scheduled for elective hepatectomy were recruited. Ninety patients were randomly allocated to receive either propofol TIVA (TIVA group) or inhalational anaesthesia with sevoflurane (SEVO group). Perioperative anaesthetic/analgesic management was the same for both groups. Numerical rating scale (NRS) pain scores, postoperative morphine consumption, quality of recovery, patient satisfaction and adverse effects were evaluated during the acute postoperative period and at 3 and 6 months after surgery.

RESULTS

No significant differences were found for acute postoperative pain scores (both at rest and during coughing) and postoperative morphine consumption between TIVA and SEVO groups. Patients given TIVA had lower pain scores with coughing at 3 months after surgery (p = 0.014, and FDR < 0.1). TIVA group was associated with better quality of recovery on postoperative day (POD) 3 (p = 0.038, and FDR < 0.1), less nausea (p = 0.011, and FDR < 0.1 on POD 2; p = 0.013, and FDR < 0.1 on POD 3) and constipation (p = 0.013, and FDR < 0.1 on POD 3).

CONCLUSION

Propofol TIVA did not improve acute postoperative pain control compared to inhalational anaesthesia in patients who underwent hepatectomy. Our results do not support the use of propofol TIVA for reducing acute postoperative pain after hepatectomy.