Current methods and challenges for acute pain clinical trials

Acute postoperative pain and catastrophizing in unicompartmental knee arthroplasty: a prospective, observational, single-center, cohort study

BACKGROUND AND OBJECTIVES

Pain catastrophizing is associated with acute pain after total knee arthroplasty. However, the association between pain catastrophizing and acute pain after unicompartmental knee arthroplasty (UKA) remains unclear.

METHODS

We investigated the incidence of predicted high-pain and low-pain responders, based on a preoperative Pain Catastrophizing Scale score >20 or ≤20, respectively, and the acute postoperative pain course in both groups. Patients undergoing UKA were consecutively included in this prospective observational cohort study. Pain at rest and during walking (5 m walk test) was evaluated preoperatively, at 24 hours postoperatively, and on days 2-7 using a pain diary.

RESULTS

125 patients were included, with 101 completing the pain diary. The incidence of predicted high-pain responders was 31% (95% CI 23% to 40%). The incidence of moderate to severe pain during walking at 24 hours postoperatively was 69% (95% CI 52% to 83%) in predicted high-pain responders and 66% (95% CI 55% to 76%) in predicted low-pain responders; OR 1.3 (95% CI 0.5 to 3.1). The incidence of moderate to severe pain at rest 24 hours postoperatively was 49% (95% CI 32% to 65%) in predicted high-pain responders and 28% (95% CI 19% to 39%) in predicted low-pain responders; OR 2.6 (95% CI 1.1 to 6.1; p=0.03). Pain catastrophizing was not associated with increased cumulated pain during walking on days 2-7.

CONCLUSIONS

The incidence of predicted high-pain responders in UKA was slightly lower than reported in total knee arthroplasty. Additionally, preoperative pain catastrophizing was not associated with acute postoperative pain during walking.

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

Opioid reduction and enhanced recovery in orthopaedic surgery (OREOS): a protocol for a feasibility randomised controlled trial in patients undergoing total knee arthroplasty

BACKGROUND

Knee arthritis is a leading cause of limited function and long-term disability in older adults. Despite a technically successful total knee arthroplasty (TKA), around 20% of patients continue to have persisting pain with reduced function, and low quality of life. Many of them continue using opioids for pain control, which puts them at risk for potential long-term adverse effects such as dependence, overdose and risk of falls. Although persisting pain and opioid use after TKA have been recognised to be important issues, individual strategies to decrease their burden have limitations and multi-component interventions, despite their potential, have not been well studied. In this study, we propose a multi-component pathway including personalized pain management, facilitated by a pain management coordinator. The objectives of this pilot trial are to evaluate feasibility (recruitment, retention, and adherence), along with opioid-free pain control at 8 weeks after TKA.

METHODS

This is a protocol for a multicentre pilot randomised controlled trial using a 2-arm parallel group design. Adult participants undergoing unilateral total knee arthroplasty will be considered for inclusion and randomised to control and intervention groups. Participants in the intervention group will receive support from a pain management coordinator who will facilitate a multicomponent pain management pathway including (1) preoperative education on pain and opioid use, (2) preoperative risk identification and mitigation, (3) personalized post-discharge analgesic prescriptions and (4) continued support for pain control and recovery up to 8 weeks post-op. Participants in the control group will undergo usual care. The primary outcomes of this pilot trial are to assess the feasibility of participant recruitment, retention, and adherence to the interventions, and key secondary outcomes are persisting pain and opioid use.

DISCUSSION

The results of this trial will determine the feasibility of conducting a definitive trial for the implementation of a multicomponent pain pathway to improve pain control and reduce harms using a coordinated approach, while keeping an emphasis on patient centred care and shared decision making.

TRIAL REGISTRATION

Prospectively registered in Clinicaltrials.gov (NCT04968132).

Psychological predictors of acute postoperative pain after total knee and hip arthroplasty: A systematic review

BACKGROUND

Identifying patients at high risk of acute postoperative pain after total knee or hip arthroplasty (TKA/THA) will facilitate individualized pain management and research on the efficacy of treatment options. Numerous studies have reported that psychological patient factors may influence acute postoperative pain, but most reviews have focused on chronic pain and functional outcomes. This systematic review aims to evaluate which psychological metrics are associated with acute postoperative pain after TKA and THA.

METHODS

A systematic search was conducted using the databases PubMed, EMBASE, Web of Science, and Cochrane Library until June 2022. Full-text articles reporting associations of preoperative psychological factors with acute pain within 48 h of TKA or THA surgery were identified. Quality was assessed using the Quality in Prognostic Studies tool.

RESULTS

Eighteen studies containing 16 unique study populations were included. TKA was the most common procedure, and anxiety and depression were the most evaluated psychological metrics. Several different anesthetic techniques and analgesic regimens were used. The studies were generally rated as having a low to moderate risk of bias. Catastrophizing was associated with acute pain in six studies (of nine), mainly after TKA. In contrast, three studies (of 13) and two studies (of 13) found anxiety and depression, respectively, to be associated with acute postoperative pain.

CONCLUSION

Pain catastrophizing seemed to be the most consistent psychological predictor of acute postoperative pain after TKA. The results for other psychological factors and THA were inconsistent. However, the interpretation of results was limited by considerable methodological heterogeneity.

The Perioperative Pain Management Bundle is Feasible: Findings From the PAIN OUT Registry

OBJECTIVES

The quality of postoperative pain management is often poor. A "bundle," a small set of evidence-based interventions, is associated with improved outcomes in different settings. We assessed whether staff caring for surgical patients could implement a "Perioperative Pain Management Bundle" and whether this would be associated with improved multidimensional pain-related patient-reported outcomes (PROs).

METHODS

"PAIN OUT," a perioperative pain registry, offers tools for auditing pain-related PROs and obtaining information about perioperative pain management during the first 24 hours after surgery. Staff from 10 hospitals in Serbia used this methodology to collect data at baseline. They then implemented the "Perioperative Pain Management Bundle" into the clinical routine and collected another round of data. The bundle consists of 4 treatment elements: (1) a full daily dose of 1 to 2 nonopioid analgesics (eg, paracetamol and/or nonsteroidal anti-inflammatory drugs), (2) at least 1 type of local/regional anesthesia, (3) pain assessment by staff, and (4) offering patients information about pain management. The primary endpoint was a multidimensional pain composite score (PCS), evaluating pain intensity, interference, and side effects that was compared between patients who received the full bundle versus not.

RESULTS

Implementation of the complete bundle was associated with a significant reduction in the PCS ( P < 0.001, small-medium effect size [ES]). When each treatment element was evaluated independently, nonopioid analgesics were associated with a higher PCS (ie, poorer outcome, and negligible ES), and the other elements were associated with a lower PCS (all negligible small ES). Individual PROs were consistently better in patients receiving the full bundle compared with 0 to 3 elements. The PCS was not associated with the surgical discipline.

DISCUSSION

We report findings from using a bundle approach for perioperative pain management in patients undergoing mixed surgical procedures. Future work will seek strategies to improve the effect.

Opiate Antagonists for Chronic Pain: A Review on the Benefits of Low-Dose Naltrexone in Arthritis versus Non-Arthritic Diseases

Chronic pain conditions create major financial and emotional burdens that can be devastating for individuals and society. One primary source of pain is arthritis, a common inflammatory disease of the joints that causes persistent pain in affected people. The main objective of pharmacological treatments for either rheumatoid arthritis (RA) or osteoarthritis (OA) is to reduce pain. Non-steroidal anti-inflammatory drugs, opioids, and opioid antagonists have each been considered in the management of chronic pain in arthritis patients. Naltrexone is an oral-activated opioid antagonist with biphasic dose-dependent pharmacodynamic effects. The molecule acts as a competitive inhibitor of opioid receptors at high doses. However, naltrexone at low doses has been shown to have hormetic effects and provides relief for chronic pain conditions such as fibromyalgia, multiple sclerosis (MS), and inflammatory bowel disorders. Current knowledge of naltrexone suggests that low-dose treatments may be effective in the treatment of pain perception in chronic inflammatory conditions observed in patients with either RA or OA. In this review, we evaluated the therapeutic benefits of low-dose naltrexone (LDN) on arthritis-related pain conditions.

Benefits versus harm of intraoperative glucocorticoid for postoperative nausea and vomiting prophylaxis

Intraoperative use of glucocorticoids is effective for postoperative nausea and vomiting prophylaxis and can also provide early postoperative analgesic effects, but the consequences for chronic post-surgical pain are debatable. In a secondary analysis of the large pragmatic Perioperative Administration of Dexamethasone and Infection trial (n=8478), the primary outcome of pain at the surgical wound at 6 months after surgery was increased in subjects receiving dexamethasone 8 mg i.v. for postoperative nausea and vomiting prophylaxis, a dose not associated with the detrimental effect of surgical site infection in the original study. In contrast, a more detailed assessment of chronic post-surgical pain after exclusion of patients with preoperative pain at the surgical site showed no differences with or without intraoperative dexamethasone regarding chronic post-surgical pain characteristics (intensity and neuropathic features). Because of several confounding factors especially regarding surgical details, these unexpected findings call for more well-designed studies about the potential risk of intraoperative treatments, such as glucocorticoids, on late post-surgical pain.

Peripheral nerve-blocks and associations with length of stay and readmissions in fast-track total hip and knee arthroplasty

BACKGROUND

Peripheral nerve blocks (PNB) have recently been recommended in total hip (THA) and knee (TKA) arthroplasty as they may reduce pain, morphine consumption, length of stay (LOS) and complications. However, whether PNBs are associated with early discharge within an enhanced recovery protocol including multimodal analgesia is uncertain.

METHODS

An observational multicenter study from January to August 2017 in six Danish Arthroplasty Centers with established fast-track protocols. Prospective recording of preoperative characteristics and information on PNB, LOS and readmissions through the Danish National Patient Registry and medical records. Multiple logistic regression was used to investigate associations between PNB and a LOS >1 day, LOS >4 days, and 30-days readmissions. We also reported on mobilization, pain, opioid and fall-related complications leading to LOS >4 days or readmissions.

RESULTS

A total of 2027 (58.6%) THA and 1432 (41.4%) TKAs with a median LOS of 1 day (IQR 1-2) and 5.3% (CI:4.6-6.1) 30-days readmission rate were identified. PNB was used in 40.7% (CI:38.2-43.3) of TKA and 2.7% (CI:2.0-3.5) of THA, but with considerable interdepartmental variation (0.0-89.0% for TKA). There was no association between PNB and LOS >1 day (OR:1.19 CI:0.82-1.72; p = .354), LOS >4 days (OR:1.4 CI:0.68-2.89; p = .359) or 30-days readmissions (OR:1.02 CI:0.63-1.65; p = .935) in TKA. Logistic regression in THA was not possible due to limited use of PNB. In TKA there were 12 (2.1% CI:1.2-3.6) with and 1 (0.1% CI:0.02-0.7) without a PNB, who had mobilization, pain or opioid-related complications, and 5 (0.9% CI:0.4-2.0) versus 4 (0.5% CI:0.2-1.2) who fell. Correspondingly, 2 (3.7% CI:1.0-12.6) and 11 (0.6% CI:0.3-1.0) of THA patients had these complications, while 0 (0.0% CI:0.0-6.6) and 17 (0.8% CI:0.5-1.3) fell.

CONCLUSION

Routine use of peripheral nerve blocks was not associated with early discharge or 30-days readmissions in fast-track THA and TKA. Future studies should focus on benefits of PNB in high-risk patients.

Evaluating the role for regional analgesia in children with spina bifida: a retrospective observational study comparing the efficacy of regional versus systemic analgesia protocols following major urological surgery

INTRODUCTION

Regional techniques are a key component of multimodal analgesia and help decrease opioid use perioperatively, but some techniques may not be suitable for all patients, such as those with spina bifida. We hypothesized peripheral regional catheters would reduce postoperative opioid use compared with no regional analgesia without increasing pain scores in pediatric patients with spina bifida undergoing major urological surgery.

METHODS

A retrospective review of a multicenter database established for the study of enhanced recovery after surgery was performed of patients from 2009 to 2021 who underwent bladder augmentation or creation of catheterizable channels. Patients without spina bifida and those receiving epidural analgesia were excluded. Opioids were converted into morphine equivalents and normalized to patient weight.

RESULTS

158 patients with pediatric spina bifida from 7 centers were included, including 87 with and 71 without regional catheters. There were no differences in baseline patient factors. Anesthesia setup increased from median 40 min (IQR 34-51) for no regional to 64 min (IQR 40-97) for regional catheters (p<0.01). The regional catheter group had lower median intraoperative opioid usage (0.24 vs 0.80 mg/kg morphine equivalents, p<0.01) as well as lower in-hospital postoperative opioid usage (0.05 vs 0.23 mg/kg/day morphine equivalents, p<0.01). Pain scores were not higher in the regional catheters group.

DISCUSSION

Continuous regional analgesia following major urological surgery in children with spina bifida was associated with a 70% intraoperative and 78% postoperative reduction in opioids without higher pain scores. This approach should be considered for similar surgical interventions in this population.

TRIAL REGISTRATION NUMBER

NCT03245242.

Celecoxib-tramadol co-crystal in patients with moderate-to-severe pain following bunionectomy with osteotomy: A phase 3, randomized, double-blind, factorial, active- and placebo-controlled trial

BACKGROUND

Celecoxib-tramadol co-crystal (CTC) is a first-in-class analgesic co-crystal of celecoxib and racemic tramadol with an improved pharmacologic profile, conferred by the co-crystal structure, compared with its active constituents administered alone/concomitantly.

AIM

We evaluated CTC in moderate-to-severe acute postoperative pain.

MATERIALS AND METHODS

This randomized, double-blind, factorial, active- and placebo-controlled phase 3 trial (NCT03108482) was conducted at 6 US clinical research centers. Adults with moderate-to-severe acute pain following bunionectomy with osteotomy were randomized to oral CTC (200 mg [112 mg celecoxib/88 mg rac-tramadol hydrochloride] every 12 h), tramadol (50 mg every 6 h), celecoxib (100 mg every 12 h), or placebo for 48 h. Patients, investigators, and personnel were blinded to assignment. The primary endpoint was the 0-48 h sum of pain intensity differences (SPID0-48) in all randomized patients. Pain intensity was assessed on a 0-10 numerical rating scale (NRS). Safety was analyzed in patients who received study medication. Funded by ESTEVE Pharmaceuticals.

RESULTS

In 2017 (March to November), 1323 patients were screened and 637 randomized to CTC (n = 184), tramadol (n = 183), celecoxib (n = 181), or placebo (n = 89). Mean baseline NRS was 6.7 in all active groups. CTC had a significantly greater effect on SPID0-48 (least-squares mean: -139.1 [95% confidence interval: -151.8, -126.5]) than tramadol (-109.1 [-121.7, -96.4]; p < 0.001), celecoxib (-103.7 [-116.4, -91.0]; p < 0.001), or placebo (-74.6 [-92.5, -56.6]; p < 0.001). Total treatment-emergent adverse events (TEAEs) were 358 for CTC and 394 for tramadol. Drug-related TEAEs occurred in 37.7% patients in the CTC group, compared with 48.6% in the tramadol group. There were no serious TEAEs/deaths.

CONCLUSION

CTC provided greater analgesia than comparable daily doses of tramadol and celecoxib, with similar tolerability to tramadol. CTC is approved in the United States.

Intravenous diclofenac and orphenadrine for the treatment of postoperative pain after remifentanil-based anesthesia : A double-blinded, randomized, placebo-controlled study

BACKGROUND

Postoperative intravenous diclofenac reduces patient opioid demand and is commonly used in surgical units. Orphenadrine is mainly used in combination with diclofenac for musculoskeletal injuries and postoperative pain control. The objective of this study was to compare the analgesic efficacy of diclofenac-orphenadrine, diclofenac alone and saline.

METHODS

We performed a double-blind, randomized, placebo-controlled, parallel-group, single-center clinical study investigating the opioid-sparing effect of a combination of diclofenac and orphenadrine versus diclofenac alone versus isotonic saline solution. Initially 72 patients were included and received total intravenous anesthesia during cruciate ligament surgery. All patients were postoperatively treated with a patient-controlled analgesia (PCA) device containing hydromorphone. Pharmacological safety was assessed by laboratory parameters, vital signs, and delirium detection scores.

RESULTS

There was no significant difference between the groups in cumulative dose of PCA analgesics required after 24 h postsurgery, with 5.90 mg (SD ± 2.90 mg) in the placebo group, 5.73 mg (SD ± 4.75 mg) in the diclofenac group, and 4.13 mg (SD ± 2.57 mg) in the diclofenac-orphenadrine group. Furthermore, there was no significant difference between the groups in cumulative dose of PCA analgesics required 2 h postsurgery (n = 65). Mean dose of hydromorphone required after 2 h was 1.54 mg (SD ± 0.57 mg) in the placebo group, 1.56 mg (SD ± 1.19 mg) in the diclofenac-only group, and 1.37 mg (SD ± 0.78 mg) in the diclofenac-orphenadrine group. However, when comparing the diclofenac-orphenadrine group and the diclofenac group combined to placebo there was a significant reduction in PCA usage in the first 24 h postsurgery. In total, there were 25 adverse events reported, none of which were rated as severe.

CONCLUSION

Orphenadrine-diclofenac failed to significantly reduce postoperative opioid requirements. However, in an exploratory post hoc analysis the diclofenac-orphenadrine and the diclofenac group combined versus placebo showed a tendency to reduce opioid demand in postoperative pain control. Further research is required to determine the value of orphenadrine as an adjuvant in a multimodal approach for postoperative pain management.

OVER THE COUNTER ANALGESICS ARE EFFECTIVE IN TREATING ORTHODONTIC PAIN

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION

The efficacy of analgesics in controlling orthodontic pain: a systematic review and meta- analysis. Cheng C, Xie T, Wang J. BMC Oral Health 2020; 20:259.

SOURCE OF FUNDING

The systematic review was funded by grants from the National Natural Science Foundation of China (No. 81771114 and No. 81970967). The authors have no actual or potential conflicts of interest.

TYPE OF STUDY/DESIGN

Systematic review with meta-analysis of data.

The influence of involving patients in postoperative pain treatment decisions on pain-related patient-reported outcomes: A STROBE-compliant registering observational study

The evidence regarding the influence of allowing patients to participate in postoperative pain treatment decisions on acute pain management is contradictory. This study aimed to identify the role of patient participation in influencing pain-related patient-reported outcomes (PROs). This is a cross-sectional study. The data were provided by PAIN OUT (www.pain-out.eu). A dataset specific to adult Chinese patients undergoing orthopedic surgery was selected. The PROs were assessed on postoperative day 1. The patient participant was assessed using an 11-point scale. Participants who reported >5 were allocated to the "participation" group, and those who reported ≤5 were allocated to the "nonparticipation" group. A 1:1 propensity score matching was conducted. The primary outcome was the desire for more pain treatment. All other items of PROs were the secondary outcomes comprising pain intensity, interference of pain with function, emotional impairment, adverse effects, and other patient perception. From February 2014 to November 2020, 2244 patients from 20 centers were approached, of whom 1804 patients were eligible and 726 pairs were matched. There was no significant difference between the groups in the desire for more pain treatment either before (25.4% vs 28.2%, risk ratio [95% CI]: 0.90 [0.77, 1.05], P = .18) or after matching (26.7% vs 28.8%, risk ratio [95% CI]: 0.93 [0.79, 1.10], P = .43). After matching, patients in the participation group reported significantly better PROs, including pain intensity (less time spent in severe pain [P < .01]), emotional impairment (less anxiety [P < .01]), interference with function (less interference with sleep [P < .01]), adverse effects (less drowsiness [P = .01]), and patient perception (more pain relief [P < .01] and more satisfaction [P < .01]), than the nonparticipation group. Patient participation in pain treatment decisions was associated with improved pain experience but failed to mitigate the desire for more treatment.

Pain management after total knee arthroplasty: PROcedure SPEcific Postoperative Pain ManagemenT recommendations

BACKGROUND

The PROSPECT (PROcedure SPEcific Postoperative Pain ManagemenT) Working Group is a global collaboration of surgeons and anaesthesiologists formulating procedure-specific recommendations for pain management after common operations. Total knee arthroplasty (TKA) is associated with significant postoperative pain that is difficult to treat. Nevertheless, pain control is essential for rehabilitation and to enhance recovery.

OBJECTIVE

To evaluate the available literature and develop recommendations for optimal pain management after unilateral primary TKA.

DESIGN

A narrative review based on published systematic reviews, using modified PROSPECT methodology.

DATA SOURCES

A literature search was performed in EMBASE, MEDLINE, PubMed and Cochrane Databases, between January 2014 and December 2020, for systematic reviews and meta-analyses evaluating analgesic interventions for pain management in patients undergoing TKA.

ELIGIBILITY CRITERIA

Each randomised controlled trial (RCT) included in the selected systematic reviews was critically evaluated and included only if met the PROSPECT requirements. Included studies were evaluated for clinically relevant differences in pain scores, use of nonopioid analgesics, such as paracetamol and nonsteroidal anti-inflammatory drugs and current clinical relevance.

RESULTS

A total of 151 systematic reviews were analysed, 106 RCTs met PROSPECT criteria. Paracetamol and nonsteroidal anti-inflammatory or cyclo-oxygenase-2-specific inhibitors are recommended. This should be combined with a single shot adductor canal block and peri-articular local infiltration analgesia together with a single intra-operative dose of intravenous dexamethasone. Intrathecal morphine (100 μg) may be considered in hospitalised patients only in rare situations when both adductor canal block and local infiltration analgesia are not possible. Opioids should be reserved as rescue analgesics in the postoperative period. Analgesic interventions that could not be recommended were also identified.

CONCLUSION

The present review identified an optimal analgesic regimen for unilateral primary TKA. Future studies to evaluate enhanced recovery programs and specific challenging patient groups are needed.

Status quo of pain-related patient reported outcomes and perioperative pain management in 10 415 patients from 10 countries: analysis of registry data

BACKGROUND

Postoperative pain is common at the global level, despite considerable attempts for improvement, reflecting the complexity of offering effective pain relief. In this study, clinicians from Mexico, China, and eight European countries evaluated perioperative pain practices and patient-reported outcomes (PROs) in their hospitals as a basis for carrying out quality improvement (QI) projects in each country.

METHODS

PAIN OUT, an international perioperative pain registry, provided standardized methodology for assessing management and multi-dimensional PROs on the first postoperative day, in patients undergoing orthopedic, general surgery, obstetric & gynecology or urological procedures.

RESULTS

Between 2017-2019, data obtained from 10,415 adult patients in 105 wards, qualified for analysis. At the ward level: 50% (median) of patients reported worst pain intensities ≥7/10 NRS, 25% spent ≥50% of the time in severe pain and 20-34% reported severe ratings for pain-related functional and emotional interference. Demographic variables, country and surgical discipline explained a small proportion of the variation in the PROs, leaving about 88% unexplained. Most treatment processes varied considerably between wards. Ward effects accounted for about 7% and 32% of variation in PROs and treatment processes, respectively.

CONCLUSIONS

This comprehensive evaluation demonstrates that many patients in this international cohort reported poor pain-related PROs on the first postoperative day. PROs and treatments varied greatly. Most of the variance of the PROs could not be explained. The findings served as a basis for devising and implementing QI programs in participating hospitals.

Opioid versus opioid-free analgesia after surgical discharge: a systematic review and meta-analysis of randomised trials

BACKGROUND

Excessive opioid prescribing after surgery has contributed to the current opioid crisis; however, the value of prescribing opioids at surgical discharge remains uncertain. We aimed to estimate the extent to which opioid prescribing after discharge affects self-reported pain intensity and adverse events in comparison with an opioid-free analgesic regimen.

METHODS

In this systematic review and meta-analysis, we searched MEDLINE, Embase, the Cochrane Library, Scopus, AMED, Biosis, and CINAHL from Jan 1, 1990, until July 8, 2021. We included multidose randomised controlled trials comparing opioid versus opioid-free analgesia in patients aged 15 years or older, discharged after undergoing a surgical procedure according to the Physiological and Operative Severity Score for the Enumeration of Mortality and Morbidity definition (minor, moderate, major, and major complex). We screened articles, extracted data, and assessed risk of bias (Cochrane's risk-of-bias tool for randomised trials) in duplicate. The primary outcomes of interest were self-reported pain intensity on day 1 after discharge (standardised to 0-10 cm visual analogue scale) and vomiting up to 30 days. Pain intensity at further timepoints, pain interference, other adverse events, risk of dissatisfaction, and health-care reutilisation were also assessed. We did random-effects meta-analyses and appraised evidence certainty using the Grading of Recommendations, Assessment, Development, and Evaluations scoring system. The review was registered with PROSPERO (ID CRD42020153050).

FINDINGS

47 trials (n=6607 patients) were included. 30 (64%) trials involved elective minor procedures (63% dental procedures) and 17 (36%) trials involved procedures of moderate extent (47% orthopaedic and 29% general surgery procedures). Compared with opioid-free analgesia, opioid prescribing did not reduce pain on the first day after discharge (weighted mean difference 0·01cm, 95% CI -0·26 to 0·27; moderate certainty) or at other postoperative timepoints (moderate-to-very-low certainty). Opioid prescribing was associated with increased risk of vomiting (relative risk 4·50, 95% CI 1·93 to 10·51; high certainty) and other adverse events, including nausea, constipation, dizziness, and drowsiness (high-to-moderate certainty). Opioids did not affect other outcomes.

INTERPRETATION

Findings from this meta-analysis support that opioid prescribing at surgical discharge does not reduce pain intensity but does increase adverse events. Evidence relied on trials focused on elective surgeries of minor and moderate extent, suggesting that clinicians can consider prescribing opioid-free analgesia in these surgical settings. Data were largely derived from low-quality trials, and none involved patients having major or major-complex procedures. Given these limitations, there is a great need to advance the quality and scope of research in this field.

FUNDING

The Canadian Institutes of Health Research.

A high stress profile is associated with severe pain in oncology patients receiving chemotherapy

PURPOSE

Oncology patients receiving chemotherapy can experience both cancer and non-cancer pain. In addition, oncology patients face numerous stressors and their responses are highly variable. Stress and pain are intricately linked. The purpose of this study was to evaluate for differences in pain characteristics and mood disturbance among oncology patients with distinct stress profiles.

METHODS

From a sample of 957 patients with and without pain, latent profile analysis identified three groups of patients with distinct stress profiles (i.e., Stressed, Normative, Resilient). In the subset of 671 patients with pain, receiving chemotherapy for breast, lung, gastrointestinal, or gynecologic cancer, we evaluated for differences among the stress profiles in terms of pain characteristics (e.g., intensity, qualities, interference) and mood disturbance (anxiety, depressive symptoms).

RESULTS

Compared to Normative patients (n = 333; 49.6%), Stressed patients (n = 305; 45.5%) reported higher levels of pain intensity, pain interference, anxiety, and depressive symptoms and more commonly described pain as throbbing, shooting, burning, exhausting, tiring, penetrating, nagging, miserable, and unbearable. Compared to Resilient patients (n = 33; 4.9%), Stressed patients reported significantly higher mood-related pain interference scores and more severe anxiety and depressive symptoms.

CONCLUSIONS

A high stress profile is common (45.5%) and is associated with more severe pain and associated symptoms. Efforts to identify and target this group for interventions may improve patient outcomes.

Evaluation of Different Pain-Control Procedures for Post-cardiac Surgery: A Systematic Review and Network Meta-Analysis

Objective

To identify superior pain-control procedures for postoperative patients who undergo cardiac surgeries.

Methods

Literature searches were conducted in globally recognized databases, including MEDLINE, EMBASE and Cochrane Central, to identify randomized controlled trials (RCTs) investigating pain-control procedures after cardiac surgeries. The parameters evaluating analgesic efficacy and postoperative recovery, namely, the pain score and ICU stay, were quantitatively pooled and estimated using Bayesian methods. The values of the surface under the cumulative ranking (SUCRA) probabilities regarding each parameter were calculated to enable the ranking of various pain-control procedures. Node-splitting analysis was performed to test the inconsistency of the main results, and the publication bias was assessed by examining the funnel-plot symmetry.

Results

After a detailed review, 13 RCTs containing 7 different procedures were included in the network meta-analysis. After pooling the results together, an erector spinae plane block (ESPB) and a local parasternal block (LPB) plus target-controlled infusion (TCI) presented the best analgesic effects for reducing pain at rest (SUCRA, .47) and during movement (SUCRA, .52), respectively, while the former also achieved the shortest ICU stay (SUCRA, .48). Moreover, the funnel-plot symmetries showed no inconsistencies or obvious publication bias in the current study.

Conclusions

The current evidence indicates that ESPB is a potential superior analgesic strategy for post-cardiac surgery patients. To verify this conclusion further, it is imperative to obtain more high-quality evidence and conduct relevant investigations in the future.

Opioid-free versus opioid-based anesthesia in pancreatic surgery

BACKGROUND

Opioid-free anesthesia (OFA) is associated with significantly reduced cumulative postoperative morphine consumption in comparison with opioid-based anesthesia (OBA). Whether OFA is feasible and may improve outcomes in pancreatic surgery remains unclear.

METHODS

Perioperative data from 77 consecutive patients who underwent pancreatic resection were included and retrospectively reviewed. Patients received either an OBA with intraoperative remifentanil (n = 42) or an OFA (n = 35). OFA included a combination of continuous infusions of dexmedetomidine, lidocaine, and esketamine. In OBA, patients also received a single bolus of intrathecal morphine. All patients received intraoperative propofol, sevoflurane, dexamethasone, diclofenac, neuromuscular blockade. Postoperative pain management was achieved by continuous wound infiltration and patient-controlled morphine. The primary outcome was postoperative pain (Numerical Rating Scale, NRS). Opioid consumption within 48 h after extubation, length of stay, adverse events within 90 days, and 30-day mortality were included as secondary outcomes. Episodes of bradycardia and hypotension requiring rescue medication were considered as safety outcomes.

RESULTS

Compared to OBA, NRS (3 [2-4] vs 0 [0-2], P < 0.001) and opioid consumption (36 [24-52] vs 10 [2-24], P = 0.005) were both less in the OFA group. Length of stay was shorter by 4 days with OFA (14 [7-46] vs 10 [6-16], P < 0.001). OFA (P = 0.03), with postoperative pancreatic fistula (P = 0.0002) and delayed gastric emptying (P < 0.0001) were identified as only independent factors for length of stay. The comprehensive complication index (CCI) was the lowest with OFA (24.9 ± 25.5 vs 14.1 ± 23.4, P = 0.03). There were no differences in demographics, operative time, blood loss, bradycardia, vasopressors administration or time to extubation among groups.

CONCLUSIONS

In this series, OFA during pancreatic resection is feasible and independently associated with a better outcome, in particular pain outcomes. The lower rate of postoperative complications may justify future randomized trials to test the hypothesis that OFA may improve outcomes and shorten length of stay.

Responsiveness of quantitative sensory testing-derived sensory phenotype to disease-modifying intervention in patients with entrapment neuropathy: a longitudinal study

ABSTRACT

The German Research Network on Neuropathic Pain (DFNS) quantitative sensory testing (QST) method for sensory phenotyping is used to stratify patients by mechanism-associated sensory phenotype, theorised to be predictive of intervention efficacy. We hypothesised that change in pain and sensory dysfunction would relate to change in sensory phenotype. We investigated the responsiveness of sensory phenotype to surgery in patients with an entrapment neuropathy. With ethical approval and consent, this observational study recruited patients with neurophysiologically confirmed carpal tunnel syndrome. Symptom and pain severity parameters and DFNS QST were evaluated before and after carpal tunnel surgery. Surgical outcome was evaluated by patient-rated change. Symptom severity score of the Boston Carpal Tunnel Questionnaire and associated pain and paraesthesia subgroups were comparators for clinically relevant change. Quantitative sensory testing results (n = 76) were compared with healthy controls (n = 54). At 6 months postsurgery, 92% participants reported a good surgical outcome and large decrease in pain and symptom severity (P < 0.001). Change in QST parameters occurred for thermal detection, thermal pain, and mechanical detection thresholds with a moderate to large effect size. Change in mechanical pain measures was not statistically significant. Change occurred in sensory phenotype postsurgery (P < 0.001); sensory phenotype was associated with symptom subgroup (P = 0.03) and patient-rated surgical outcome (P = 0.02). Quantitative sensory testing-derived sensory phenotype is sensitive to clinically important change. In an entrapment neuropathy model, sensory phenotype was associated with patient-reported symptoms and demonstrated statistically significant, clinically relevant change after disease-modifying intervention. Sensory phenotype was independent of disease severity and may reflect underlying neuropathophysiology.

Exploring patients' experiences of analgesia after major lower limb amputation: a qualitative study

OBJECTIVES

To explore patient experiences, understanding and perceptions of analgesia following major lower limb amputation.

DESIGN

Qualitative interview study, conducted as part of a randomised controlled feasibility trial.

SETTING

Participants were recruited from two general hospitals in South Wales.

PARTICIPANTS

Interview participants were patients enrolled in PLACEMENT (Perineural Local Anaesthetic Catheter aftEr Major lowEr limb amputatioN Trial): a randomised controlled feasibility trial comparing the use of perineural catheter (PNC) versus standard care for postoperative pain relief following major lower limb amputation. PLACEMENT participants who completed 5-day postoperative follow-up, were able and willing to participate in a face-to-face interview, and had consented to be contacted, were eligible to take part in the qualitative study. A total of 20 interviews were conducted with 14 participants: 10 male and 4 female.

METHODS

Semi-structured, face-to-face interviews were conducted with participants over two time points: (1) up to 1 month and (2) at least 6 months following amputation. Interviews were audio-recorded, transcribed verbatim and analysed using a framework approach.

RESULTS

Interviews revealed unanticipated benefits of PNC usage for postoperative pain relief. Participants valued the localised and continuous nature of this mode of analgesia in comparison to opioids. Concerns about opioid dependence and side effects of pain relief medication were raised by participants in both treatment groups, with some reporting trying to limit their intake of analgesics.

CONCLUSIONS

Findings suggest routine placement of a PNC following major lower limb amputation could reduce postoperative pain, particularly for patient groups at risk of postoperative delirium. This method of analgesic delivery also has the potential to reduce preoperative anxiety, alleviate the burden of pain management and minimise opioid use. Future research could further examine the comparison between patient-controlled analgesia and continuous analgesia in relation to patient anxiety and satisfaction with pain management.

TRIAL REGISTRATION NUMBER

ISRCTN: 85710690; EudraCT: 2016-003544-37.

Consensus practice guidelines on interventions for cervical spine (facet) joint pain from a multispecialty international working group

BACKGROUND

The past two decades have witnessed a surge in the use of cervical spine joint procedures including joint injections, nerve blocks and radiofrequency ablation to treat chronic neck pain, yet many aspects of the procedures remain controversial.

METHODS

In August 2020, the American Society of Regional Anesthesia and Pain Medicine and the American Academy of Pain Medicine approved and charged the Cervical Joint Working Group to develop neck pain guidelines. Eighteen stakeholder societies were identified, and formal request-for-participation and member nomination letters were sent to those organizations. Participating entities selected panel members and an ad hoc steering committee selected preliminary questions, which were then revised by the full committee. Each question was assigned to a module composed of 4-5 members, who worked with the Subcommittee Lead and the Committee Chairs on preliminary versions, which were sent to the full committee after revisions. We used a modified Delphi method whereby the questions were sent to the committee en bloc and comments were returned in a non-blinded fashion to the Chairs, who incorporated the comments and sent out revised versions until consensus was reached. Before commencing, it was agreed that a recommendation would be noted with >50% agreement among committee members, but a consensus recommendation would require ≥75% agreement.

RESULTS

Twenty questions were selected, with 100% consensus achieved in committee on 17 topics. Among participating organizations, 14 of 15 that voted approved or supported the guidelines en bloc, with 14 questions being approved with no dissensions or abstentions. Specific questions addressed included the value of clinical presentation and imaging in selecting patients for procedures, whether conservative treatment should be used before injections, whether imaging is necessary for blocks, diagnostic and prognostic value of medial branch blocks and intra-articular joint injections, the effects of sedation and injectate volume on validity, whether facet blocks have therapeutic value, what the ideal cut-off value is for designating a block as positive, how many blocks should be performed before radiofrequency ablation, the orientation of electrodes, whether larger lesions translate into higher success rates, whether stimulation should be used before radiofrequency ablation, how best to mitigate complication risks, if different standards should be applied to clinical practice and trials, and the indications for repeating radiofrequency ablation.

CONCLUSIONS

Cervical medial branch radiofrequency ablation may provide benefit to well-selected individuals, with medial branch blocks being more predictive than intra-articular injections. More stringent selection criteria are likely to improve denervation outcomes, but at the expense of false-negatives (ie, lower overall success rate). Clinical trials should be tailored based on objectives, and selection criteria for some may be more stringent than what is ideal in clinical practice.

Supraclavicular block with Mepivacaine vs Ropivacaine, their impact on postoperative pain: a prospective randomised study

BACKGROUND

Supraclavicular block (SCB) with long-acting local anaesthetic is commonly used for surgical repair of distal radial fractures (DRF). Studies have shown a risk for rebound pain when the block fades. This randomised single-centre study aimed to compare pain and opioid consumption the first three days post-surgery between SCB-mepivacaine vs. SCB-ropivacaine, with general anaesthesia (GA) as control.

METHODS

Patients (n = 90) with ASA physical status 1-3 were prospectively randomised to receive; SCB with mepivacine 1%, 25-30 ml (n = 30), SCB with ropivacaine 0.5%, 25-30 ml (n = 30) or GA (n = 30) with propofol/fentanyl/sevoflurane. Study objectives compared postoperative pain with Numeric Rating Scale (NRS) and sum postoperative Opioid Equivalent Consumption (OEC) during the first 3 days post-surgery between study-groups.

RESULTS

The three groups showed significant differences in postoperative pain-profile. Mean NRS at 24 h was significantly lower for the SCB-mepivacaine group (p = 0.018). Further both median NRS and median OEC day 0 to 3 were significanly lower in the SCB-mepivacaine group as compared to the SCB-ropivacaine group during the first three days after surgery; pain NRS 1 (IQR 0.3-3.3) and 2.7 (IQR 1.3-4.2) (p = 0.017) and OEC 30 mg (IQR 10-80) and 85 mg (IQR 45-125) (p = 0.004), respectively. The GA-group was in between both in pain NRS and median sum OEC. Unplanned healthcare contacts were highest among SCB-ropivacaine patients (39.3%) vs. SCB-mepivacaine patients (0%) and GA-patients (3.4%).

CONCLUSIONS

The potential benefit of longer duration of analgesia, associated to a long-acting local anaesthetic agent, during the early postoperative course must be put in perspective of potential worse pain progression following block resolution.

TRIAL REGISTRATION

NCT03749174 (clinicaltrials.gov, Nov 21, 2018, retrospectively registered).

The Short Form of the Glasgow Composite Measure Pain Scale in Post-operative Analgesia Studies in Dogs: A Scoping Review

The measurement and treatment of acute pain in animals is essential from a welfare perspective. Valid pain-related outcome measures are also crucial for ensuring reliable and translatable findings in veterinary clinical trials. The short form of the Glasgow Composite Measure Pain Scale (CMPS-SF) is a multi-item behavioral pain assessment tool, developed and validated using a psychometric approach, to measure acute pain in the dog. Here we conduct a scoping review to identify prospective research studies that have used the CMPS-SF. We aim to describe the contexts in which it has been used, verify the correct use of the scale, and examine whether these studies are well-designed and adequately powered. We identify 114 eligible studies, indicating widespread use of the scale. We also document a limited number of modifications to the scale and intervention level, which would alter its validity. A variety of methods, with no consensus, were used to analyse data derived from the scale. However, we also find many deficiencies in reporting of experimental design in terms of the observers used, the underlying hypothesis of the research, the statement of primary outcome, and the use of a priori sample size calculations. These deficiencies may predispose to both type I and type II statistical errors in the small animal pain literature. We recommend more robust use of the scale and derived data to ensure success of future studies using the tool ensuring reliable and translatable outcomes.

Transversus abdominis plane block versus quadratus lumborum block type 2 for analgesia in renal transplantation: A randomised trial

BACKGROUND

Several studies have shown an analgesic efficacy of a transversus abdominis plane block (TAPB) in reducing opioid requirements during and after cadaveric renal transplantation surgery, but the effect of a quadratus lumborum block (QLB) in this type of surgery is unclear.

OBJECTIVES

The main objective of this prospective, randomised, double-centre clinical study was to compare the analgesic efficacy of a one-sided lateral approach TAPB with a unilateral QLB type 2 in cadaveric renal transplantation surgery.

DESIGN

Randomised, single-blinded trial.

SETTING

Two University-affiliated tertiary care hospitals between April 2016 and May 2017.

PATIENTS

A total of 101 patients aged more than 18 years, scheduled for cadaveric renal transplantation.

INTERVENTIONS

On receiving ethical board approval and individual informed consent, consecutive patients were allocated randomly to receive either an ultrasound-guided single-shot lateral TAPB or an ultrasound-guided single-shot QLB type 2 on the surgical side using 20 ml of bupivacaine 0.25% with adrenaline after a standardised induction of general anaesthesia. All patients on surgical completion and recovery from general anaesthesia were admitted to the postanaesthesia care unit for 24 h. They received standardised intravenous patient-controlled analgesia with fentanyl, and their pain scores were noted at regular intervals.

MAIN OUTCOME MEASURES

The primary endpoint was total cumulative fentanyl dose used per kg body mass in the first 24 h after surgery. Secondary outcomes were the need to start a continuous infusion of fentanyl in addition to patient-controlled analgesia boluses during the stay in post-anaesthesia care unit, postoperative pain severity measured using a numerical rating scale, patient satisfaction with analgesic treatment, evidence of postoperative nausea and vomiting, pruritus and sedation level.

RESULTS

The 49 patients allocated to the QLB type 2 group used significantly less fentanyl per kg in the first 24 h after surgery than the 52 patients who received a TAPB (median [IQR] 4.2 [2.3 to 8.0] μg kg versus 6.7 [3.5 to 10.7] μg kg, P = 0.042). No statistically significant differences were noted in the secondary endpoints within the study, including the frequency of adverse effects of opioids.

CONCLUSION

The reduction of fentanyl consumption in the first 24 h after renal transplantation with no difference in pain intensity and patient satisfaction shows a beneficial effect of one-sided QLB type 2 over a one-sided TAPB in regards to postoperative analgesia. However, the reduction in opioid consumption did not affect the frequency of opioid-related adverse effects.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT02783586.

Perioperative Opioid Administration

Opioids form an important component of general anesthesia and perioperative analgesia. Discharge opioid prescriptions are identified as a contributor for persistent opioid use and diversion. In parallel, there is increased enthusiasm to advocate opioid-free strategies, which include a combination of known analgesics and adjuvants, many of which are in the form of continuous infusions. This article critically reviews perioperative opioid use, especially in view of opioid-sparing versus opioid-free strategies. The data indicate that opioid-free strategies, however noble in their cause, do not fully acknowledge the limitations and gaps within the existing evidence and clinical practice considerations. Moreover, they do not allow analgesic titration based on patient needs; are unclear about optimal components and their role in different surgical settings and perioperative phases; and do not serve to decrease the risk of persistent opioid use, thereby distracting us from optimizing pain and minimizing realistic long-term harms.

Surgery and opioids: evidence-based expert consensus guidelines on the perioperative use of opioids in the United Kingdom

There are significant concerns regarding prescription and misuse of prescription opioids in the perioperative period. The Faculty of Pain Medicine at the Royal College of Anaesthetists have produced this evidence-based expert consensus guideline on surgery and opioids along with the Royal College of Surgery, Royal College of Psychiatry, Royal College of Nursing, and the British Pain Society. This expert consensus practice advisory reproduces the Faculty of Pain Medicine guidance. Perioperative stewardship of opioids starts with judicious opioid prescribing in primary and secondary care. Before surgery, it is important to assess risk factors for continued opioid use after surgery and identify those with chronic pain before surgery, some of whom may be taking opioids. A multidisciplinary perioperative care plan that includes a prehabilitation strategy and intraoperative and postoperative care needs to be formulated. This may need the input of a pain specialist. Emphasis is placed on optimum management of pain pre-, intra-, and postoperatively. The use of immediate-release opioids is preferred in the immediate postoperative period. Attention to ensuring a smooth care transition and communication from secondary to primary care for those taking opioids is highlighted. For opioid-naive patients (patients not taking opioids before surgery), no more than 7 days of opioid prescription is recommended. Persistent use of opioid needs a medical evaluation and exclusion of chronic post-surgical pain. The lack of grading of the evidence of each individual recommendation remains a major weakness of this guidance; however, evidence supporting each recommendation has been rigorously reviewed by experts in perioperative pain management.

The use of anti-inflammatory drugs to prevent bleaching-induced tooth sensitivity is ineffective and unnecessary

Data sources The authors searched Medline via PubMed, Scopus, Web of Science, the Cochrane Library and ClinicalTrials.gov for published and unpublished clinical trials. Only randomised clinical trials, with either a parallel or crossover design, reporting the tooth sensitivity of participants undergoing in-office dental bleaching and comparing pain frequency and severity with oral premedication of a non-steroidal or other anti-inflammatory drug compared with a placebo were used in the review. Studies that evaluated the topical administration of drugs or desensitising agents were not reviewed.Study selection In total,5,050 randomised clinical studies were screened and 11 studies were included in the various meta-analyses. Nine studies examined the effect of pre-emptive analgesics on the risk of sensitivity and ten studies evaluated the effect of drugs on the severity of sensitivity; seven of these studies were assessed as having a low risk of bias.Data extraction and synthesis This systematic review and meta-analysis was conducted a priori and registered at the International Prospective Register of Systematic Reviews. There were two reviewers who extracted data from the study tables and independently performed quality assessments of the selected trials using the Office of Health Assessment and Translation risk of bias rating tool for human and animal studies. Risk ratios were calculated for the dichotomous sensitivity risk data and mean difference for measures of sensitivity intensity.Results The authors found no effect of the drugs on the risk of sensitivity. Using a visual analogue scale, the authors identified a small but clinically insignificant reduction in the level of sensitivity in the drug-treated group evaluated up to one hour after bleaching. This was not observed when a numerical rating scale was used to measure pain intensity. For the 24-hour pain data, the authors did not find any significant intensity difference between groups. Mean pain intensity scores were generally low in both experimental groups in all randomised controlled trials reviewed. Based on a visual inspection of the funnel plots of all outcomes, the authors concluded that there was no publication bias.Conclusions The data did not support the pre-emptive use of anti-inflammatory drugs in preventing or reducing the intensity of pain caused by in-office tooth bleaching.

Efficacy and Safety of Two Fixed-Dose Combinations of Tramadol Hydrochloride and Diclofenac Sodium in Postoperative Dental Pain

OBJECTIVE

To evaluate the analgesic efficacy and safety of tramadol hydrochloride/diclofenac sodium fixed-dose combination 25 mg/25 mg (FDC 25/25) and 50 mg/50 mg (FDC 50/50) vs tramadol 50 mg (T50) and diclofenac 50 mg (D50) monotherapies in acute postoperative dental pain.

SETTING

Eight sites across Mexico.

SUBJECTS

Adults (N = 829) with moderate to severe pain after third molar extraction.

DESIGN

Prospective, randomized, double-blind, diclofenac- and tramadol-controlled, parallel-group, noninferiority, phase 3 trial.

METHODS

Subjects were randomized to receive three doses (one every eight hours) of oral FDC 25/25, FDC 50/50, T50, or D50 over a 24-hour period. Pain intensity and pain relief were evaluated frequently over the 24 hours postdose. Secondary measures included peak pain relief, onset, and duration of effect. The primary objective was to compare the analgesic efficacy and safety of FDC 50/50 or analgesic noninferiority of FDC 25/25 vs D50 or T50. The primary efficacy end point was total pain relief over four hours after dose 1 (TOTPAR4).

RESULTS

TOTPAR4 scores showed that FDC 25/25 was noninferior (P < 0.0001, delta = 1.5) and FDC 50/50 was superior (P < 0.0001) to the individual components. All secondary efficacy measures supported these results. The safety profile of FDC 25/25 and FDC 50/50 was consistent with the known safety profile of D50 and T50 monotherapies, with no unexpected safety findings observed.

CONCLUSIONS

Tramadol/diclofenac FDC 25/25 and FDC 50/50 provide superior analgesia for acute pain after third molar extraction than either of the individual components. Minor adverse effects appeared to be related to the higher doses of tramadol.

Preoperative high-dose Steroids in Total Knee and Hip Arthroplasty - Protocols for three randomized controlled trials

BACKGROUND

Patients undergoing total knee arthroplasty (TKA)/ total hip arthroplasty (THA) still experience moderate-severe postoperative pain despite optimized pain management regimes. The patients already on opioid treatment and pain catastrophizers (PCs) have a higher risk of postoperative pain. The use of preoperative intravenous high-dose glucocorticoids decreases postoperative pain after TKA and THA, but optimal dose is yet to be found, and the effect on subpopulations at high pain risk is unknown.

AIM

To investigate the effect of a higher than previously used dose of glucocorticoids (dexamethasone (DXM)), administered intravenously before surgery, as part of standardized fast-track regimen, on postoperative pain in TKA/THA subgroups.

METHOD

Three separate randomized, double-blinded, controlled trials were planned to compare a new higher dose DXM (1 mg/kg) to the earlier used high-dose DXM (0.3 mg/kg). Study 1: predicted Low Pain TKA; study 2: predicted High Pain Responder (HPR) TKA; study 3: predicted HPR THA. Predicted HPR groups consist of either PCs with PCS-score of ≥ 21 and/or history of ongoing opioid-treatment of 30 mg/day of morphine or equivalents > 30 days. In total, 408 patients were planned for inclusion (160 Low Pain TKA, 88 HPR TKA, 160 HPR THA).

PRIMARY OUTCOME

Pain upon ambulation in a 5-meter walk test 24 hours after surgery. Secondary outcomes include use of analgesics, rescue-opioids, antiemetics, cumulated pain, CRP, OR-SDS, QoR-15, quality of sleep, length of stay (LOS), reasons for hospitalization, readmission, morbidity, and mortality. Patients completed follow-up on day 90. Recruiting commenced February 2019 and is expected to finish in September 2020.

Leftover opioids following adult surgical procedures: a systematic review and meta-analysis

BACKGROUND

US opioid prescribing and use escalated over the last two decades, with parallel increases in opioid misuse, opioid-related deaths, and concerns about diversion. Postoperatively prescribed opioids contribute to these problems. Policy makers have addressed this issue by limiting postoperative opioid prescribing. However, until recently, little data existed to guide prescribers on opioid needs postoperatively. This meta-analysis quantitatively integrated the growing literature regarding extent of opioids leftover after surgery and identified factors associated with leftover opioid proportions.

METHODS

We conducted a meta-analysis of observational studies quantifying postoperative opioid consumption in North American adults, and evaluated effect size moderators using robust variance estimation meta-regression. Medline, EMBASE, Cumulative Index of Nursing and Allied Health Literature, and Cochrane Database of Systematic Reviews were searched for relevant articles published January 1, 2000 to November 10, 2018. The Methodological Index for Non-Randomized Studies (MINORS) tool assessed risk of study bias. The proportion effect size quantified the primary outcome: proportion of prescribed postoperative opioids leftover at the time of follow-up. Primary meta-regression analyses tested surgical type, amount of opioids prescribed, and study publication year as possible moderators. Secondary meta-regression models included surgical invasiveness, age, race, gender, postoperative day of data collection, and preoperative opioid use.

RESULTS

We screened 911 citations and included 44 studies (13,068 patients). The mean weighted effect size for proportion of postoperative opioid prescriptions leftover was 61% (95% CI, 56-67%). Meta-regression models revealed type of surgical procedure and level of invasiveness had a statistically significant effect on proportion of opioids leftover. Proportion of opioids leftover was greater for "other soft tissue" surgeries than abdominal/pelvic surgeries, but did not differ significantly between orthopedic and abdominal/pelvic surgeries. Minimally invasive compared to open surgeries resulted in a greater proportion of opioids leftover. Limitations include predominance of studies from academic settings, inconsistent reporting of confounders, and a possible publication bias toward studies reporting smaller leftover opioid proportions.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

A significant proportion of opioids are leftover postoperatively. Surgery type and level of invasiveness affect postoperative opioid consumption. Integration of such factors into prescribing guidelines may help minimize opioid overprescribing while adequately meeting analgesic needs.

A systematic review of pain outcomes reported by randomised trials of hip and knee arthroplasty

It is difficult to pool results from randomised clinical trials that report different outcomes. We want to develop a core set of pain-related outcomes after total hip or knee arthroplasty, the first stage of which is to systematically review published outcomes. We searched PubMed, Embase and CENTRAL for relevant trials to January 2020. We identified 165 outcomes from 565 trials with 50,668 participants, which we categorised into six domains: pain; analgesic consumption; quality of care; adverse events; mobility; and patient-reported outcome measures. The outcome in each domain reported by most trials was: visual analogue score for pain, 401 (71%); morphine consumption, 212 (38%); length of hospital stay, 166 (29%); nausea or vomiting, 425 (75%); range of motion, 173 (31%); and patient satisfaction score, 181 (32%). A primary outcome was reported in 281 (50%) trials: 101 (18%) trials reported consumption of rescue analgesics and 95 (17%) trials reported pain. We plan to publish a consensus on outcomes that should be reported in postoperative pain trials after hip or knee arthroplasty.

AAAPT Diagnostic Criteria for Acute Knee Arthroplasty Pain

OBJECTIVE

The relationship between preexisting osteoarthritic pain and subsequent post-total knee arthroplasty (TKA) pain is not well defined. This knowledge gap makes diagnosis of post-TKA pain and development of management plans difficult and may impair future investigations on personalized care. Therefore, a set of diagnostic criteria for identification of acute post-TKA pain would inform standardized management and facilitate future research.

METHODS

The Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks (ACTTION) public-private partnership with the US Food and Drug Administration (FDA), the American Pain Society (APS), and the American Academy of Pain Medicine (AAPM) formed the ACTTION-APS-AAPM Pain Taxonomy (AAAPT) initiative to address this goal. A multidisciplinary work group of pain experts was invited to conceive diagnostic criteria and dimensions of acute post-TKA pain.

RESULTS

The working group used contemporary literature combined with expert opinion to generate a five-dimensional taxonomical structure based upon the AAAPT framework (i.e., core diagnostic criteria, common features, modulating factors, impact/functional consequences, and putative mechanisms) that characterizes acute post-TKA pain.

CONCLUSIONS

The diagnostic criteria created are proposed to define the nature of acute pain observed in patients following TKA.

Domain Heterogeneity in Radiofrequency Therapies for Pain Relief: A Computational Study with Coupled Models

The objective of the current research work is to study the differences between the predicted ablation volume in homogeneous and heterogeneous models of typical radiofrequency (RF) procedures for pain relief. A three-dimensional computational domain comprising of the realistic anatomy of the target tissue was considered in the present study. A comparative analysis was conducted for three different scenarios: (a) a completely homogeneous domain comprising of only muscle tissue, (b) a heterogeneous domain comprising of nerve and muscle tissues, and (c) a heterogeneous domain comprising of bone, nerve and muscle tissues. Finite-element-based simulations were performed to compute the temperature and electrical field distribution during conventional RF procedures for treating pain, and exemplified here for the continuous case. The predicted results reveal that the consideration of heterogeneity within the computational domain results in distorted electric field distribution and leads to a significant reduction in the attained ablation volume during the continuous RF application for pain relief. The findings of this study could provide first-hand quantitative information to clinical practitioners about the impact of such heterogeneities on the efficacy of RF procedures, thereby assisting them in developing standardized optimal protocols for different cases of interest.

Opioid versus opioid-free analgesia after surgical discharge: protocol for a systematic review and meta-analysis

INTRODUCTION

Excessive prescribing after surgery has contributed to a public health crisis of opioid addiction and overdose in North America. However, the value of prescribing opioids to manage postoperative pain after surgical discharge remains unclear. We propose a systematic review and meta-analysis to assess the extent to which opioid analgesia impact postoperative pain intensity and adverse events in comparison to opioid-free analgesia in patients discharged after surgery.

METHODS AND ANALYSIS

Major electronic databases (MEDLINE, Embase, Cochrane Library, Scopus, AMED, BIOSIS, CINAHL and PsycINFO) will be searched for multi-dose randomised-trials examining the comparative effectiveness of opioid versus opioid-free analgesia after surgical discharge. Studies published from January 1990 to July 2019 will be targeted, with no language restrictions. The search will be re-run before manuscript submission to include most recent literature. We will consider studies involving patients undergoing minor and major surgery. Teams of reviewers will, independently and in duplicate, assess eligibility, extract data and evaluate risk of bias. Our main outcomes of interest are pain intensity and postoperative vomiting. Study results will be pooled using random effects models. When trials report outcomes for a common domain (eg, pain intensity) using different scales, we will convert effect sizes to a common standard metric (eg, Visual Analogue Scale). Minimally important clinical differences reported in previous literature will be considered when interpreting results. Subgroup analyses defined a priori will be conducted to explore heterogeneity. Risk of bias will be assessed according to the Cochrane Collaboration's Risk of Bias Tool 2.0. The quality of evidence for all outcomes will be evaluated using the GRADE rating system.

ETHICS AND DISSEMINATION

Ethical approval is not required since this is a systematic review of published studies. Our results will be published in a peer-reviewed journal and presented at relevant conferences. Further knowledge dissemination will be sought via public and patient organisations focussed on pain and opioid-related harms.

Current Status and Future Directions of Pain-Related Outcome Measures for Post-Surgical Pain Trials

Background: Clinical trials remain vital in order to: A) develop new treatment interventions, and also, B) to guide optimal use of current interventions for the treatment and prevention of acute and chronic postsurgical pain. Measures of pain (e.g. intensity and relief) and opioid use have been validated for the settings of postsurgical pain and continue to effectively guide research in this field..

Methods: This narrative review considers needs for innovation in postsurgical pain trial outcomes assessment.

Results: Future improvements are needed and include: A) more widespread measurement of movement-evoked pain with validation of various procedure-relevant movemen-tevoked pain maneuvers; B) new validated analytical approaches to integrate early postoperative pain scores with opioid use; and, C) closer attention to the measurement of postoperative opioid use after hospital discharge. In addition to these traditional measures, consideration is being given to the use of new pain-relevant outcome domains that include: 1) other symptoms (e.g. nausea and vomiting), 2) recovery of physiological function (e.g. respiratory, gastrointestinal, genitourinary and musculoskeletal), 3) emotional function (e.g. depression, anxiety) and, 4) development of chronic postsurgical pain. Also, there is a need to develop pain-related domains and measures for evaluating both acute and chronic post-operative pain. Finally, evidence suggests that further needs for improvements in safety assessment and reporting in postsurgical pain trials is needed, e.g. by using an agreed upon, standardized collection of outcomes that will be reported as a minimum in all postsurgical pain trials.

Conclusions: These proposed advances in outcome measurement methodology are expected to improve the success by which postsurgical pain trials guide improvements in clinical care and patient outcomes.