Local anaesthetics and regional anaesthesia for preventing chronic pain after surgery

How to Modulate Peripheral and Central Nervous System to Treat Acute Postoperative Pain and Prevent Pain Persistence

Chronic postoperative pain (CPSP) is a major issue after surgery, which may impact on patient's quality of life. Traditionally, CPSP is believed to rely on maladaptive hyperalgesia and risk factors have been identified that predispose to CPSP, including acute postoperative pain. Despite new models of prediction are emerging, acute pain is still a modifiable factor that can be challenged with perioperative analgesic strategies. In this review we present the issue of CPSP, focusing on molecular mechanism underlying the development of acute and chronic hyperalgesia. Also, we focus on how perioperative strategies can impact directly or indirectly (by reducing postoperative pain intensity) on the development of CPSP.

The postoperative analgesic efficacy of different regional anesthesia techniques in breast cancer surgery: A network meta-analysis

Background

Regional anesthesia have been successfully performed for pain management in breast cancer surgery, but it is unclear which is the best regional anesthesia technique. The aim of the present network meta-analysis was to assess the analgesic efficacy and disadvantages of regional anesthesia techniques.

Methods

Multiple databases were searched for randomized controlled trials (RCTs). The association between regional anesthesia and analgesic efficacy was evaluated by Bayesian network meta-analysis.

Results

We included 100 RCTs and 6639 patients in this study. The network meta-analysis showed that paravertebral nerve block, pectoral nerve-2 block, serratus anterior plane block, erector spinae plane block, rhomboid intercostal block, and local anesthetic infusion were associated with significantly decreased postoperative pain scores, morphine consumption and incidence of postoperative nausea and vomiting compared with no block. Regarding the incidence of chronic pain, no significance was detected between the different regional anesthesia techniques. In the cumulative ranking curve analysis, the rank of the rhomboid intercostal block was the for postoperative care unit pain scores, postoperative 24-hour morphine consumption, and incidence of postoperative nausea and vomiting.

Conclusion

Regional anesthesia techniques including, paravertebral nerve block, pectoral nerve-2 block, serratus anterior plane block, erector spinae plane block, rhomboid intercostal block, and local anesthetic infusion, can effectively alleviate postoperative acute analgesia and reduce postoperative morphine consumption, but cannot reduce chronic pain after breast surgery. The rhomboid intercostal block might be the optimal technique for postoperative analgesia in breast cancer surgery, but the strength of the evidence was very low.

Systematic review registration

https://www.crd.york.ac.uk/prospero/(PROSPERO), identifier CRD 42020220763.

V-NOTES hysterectomy under spinal anaesthesia: A pilot study

Background: Spinal anaesthesia has not been widely adopted for laparoscopic surgeries until now. There are a few studies that have shown that spinal anaesthesia is at least as safe as general anaesthesia. The need for additional analgesics can be reduced by utilising early postoperative analgesic effects of spinal anaesthesia, and maximum benefit can be obtained from minimally invasive approaches when V-NOTES surgery is performed under spinal anaesthesia. Objective: Combining V-NOTES with spinal anaesthesia to improve minimally invasive surgical techniques and provide maximum benefit to patients. Materials and methods: Patients who were found to have benign pelvic organ pathologies, required a hysterectomy and were considered suitable for V-NOTES hysterectomy under spinal anaesthesia were included in this study. Spinal anaesthesia was achieved with 12.5 mg 0.5% hyperbaric bupivacaine in the sitting position. Perioperative events and complications related to spinal anaesthesia were noted. Postoperatively, the pain was evaluated using a visual analogue scale at the 6th, 12th, and 24th hours. Main outcome measures: To evaluate the feasibility and safety of spinal anaesthesia in VNOTES hysterectomy and to increase the advantages of minimally invasive surgical procedures. Results: No conversion to conventional laparoscopy or laparotomy was required in all six operated patients. Conversion from spinal anaesthesia to general anaesthesia was unnecessary, and no major perioperative incident occurred in any of the cases. Conclusion: In the current study by our team, we demonstrated that V-NOTES hysterectomy could be performed safely under spinal anaesthesia in well-selected patients. The need for additional analgesics can be reduced by utilising early postoperative analgesic effects of spinal anaesthesia, and maximum benefit can be obtained from minimally invasive approaches when VNOTES surgery is performed under spinal anaesthesia. What is new? V-NOTES hysterectomy could be performed safely under spinal anaesthesia in well-selected patients.

Regional anesthesia and acute perioperative pain management in thoracic surgery: a narrative review

Background and Objective

Thoracic surgery causes significant pain which can negatively affect pulmonary function and increase risk of postoperative complications. Effective analgesia is important to reduce splinting and atelectasis. Systemic opioids and thoracic epidural analgesia (TEA) have been used for decades and are effective at treating acute post-thoracotomy pain, although both have risks and adverse effects. The advancement of thoracoscopic surgery, a focus on multimodal and opioid-sparing analgesics, and the development of ultrasound-guided regional anesthesia techniques have greatly expanded the options for acute pain management after thoracic surgery. Despite the expansion of surgical techniques and analgesic approaches, there is no clear optimal approach to pain management. This review aims to summarize the body of literature regarding systemic and regional anesthetic techniques for thoracic surgery in both thoracotomy and minimally invasive approaches, with a goal of providing a foundation for providers to make individualized decisions for patients depending on surgical approach and patient factors, and to discuss avenues for future research.

Methods

We searched PubMed and Google Scholar databases from inception to May 2021 using the terms “thoracic surgery”, “thoracic surgery AND pain management”, “thoracic surgery AND analgesia”, “thoracic surgery AND regional anesthesia”, “thoracic surgery AND epidural”. We considered articles written in English and available to the reader.

Key Content and Findings

There is a wide variety of strategies for treating acute pain after thoracic surgery, including multimodal opioid and non-opioid systemic analgesics, regional anesthesia including TEA and paravertebral blocks (PVB), and a recent expansion in the use of novel fascial plane blocks especially for thoracoscopy. The body of literature on the effectiveness of different approaches for thoracotomy and thoracoscopy is a rapidly expanding field and area of active debate.

Conclusions

The optimal analgesic approach for thoracic surgery may depend on patient factors, surgical factors, and institutional factors. Although TEA may provide optimal analgesia after thoracotomy, PVB and emerging fascial plane blocks may offer effective alternatives. A tailored approach using multimodal systemic therapies and regional anesthesia is important, and future studies comparing techniques are necessary to further investigate the optimal approach to improve patient outcomes.

Avoid Postoperative Pain To Prevent Its Chronification: A Narrative Review

Acute postoperative pain is a normal and expected part of the patient’s postsurgical trajectory, and its intensity, severity, and duration vary with surgery-related and patient factors. In a subset of patients, postoperative pain does not resolve as the tissue heals but instead transitions to chronic postoperative pain, a challenging condition to treat and one associated with decreased quality of life, sleep and mood disorders, and neuropathy. Promptly and adequately treating acute postoperative pain can reduce the risk that it will transition into chronic postoperative pain. Numerous agents are available that may help treat postoperative pain, including nonsteroidal anti-inflammatory drugs, opioids, antidepressants, anticonvulsants, and others. In this connection, it is also important to consider patient factors, such as mental health status and comorbidities, as well as the type and duration of surgery. A multimodal approach is recommended, which uses two or more agents with complementary mechanisms of action, working at different targets. Multimodal analgesia may also reduce adverse events and lessen opioid consumption after surgery. A particularly useful fixed-dose combination product is dexketoprofen/tramadol (DEX-TRA), which is safe and effective in numerous clinical trials. This review is based on a presentation from the Roma Pain Days scientific sessions of 2021.

The Routes of Administration for Acute Postoperative Pain Medication

Effective treatment of postoperative acute pain, together with early mobilization and nutrition, is one of the perioperative strategies advocated to improve surgical outcome and reduce the costs of hospitalization. Moreover, adequate pain control reduces perioperative morbidity related to surgical stress and can also prevent the incidence of chronic postoperative pain syndromes, whose treatment is still a challenge. The choice of the most appropriate analgesics depends not only on the drug class, but also on the most suitable route of administration, the best dosage for that route, and unique limitations and contraindications for every patient. In the present review, a comprehensive analysis was performed on the different routes of administration of acute postoperative pain medications and their indications and limitations, focusing on recent evidence and international recommendations.

Surgical prevention of terminal neuroma and phantom limb pain: a literature review

The incidence of extremity amputation is estimated at about 200,000 cases annually. Over 25% of patients suffer from terminal neuroma or phantom limb pain (TNPLP), resulting in pain, inability to wear a prosthetic device, and lost work. Once TNPLP develops, there is no definitive cure. Therefore, there has been an emerging focus on TNPLP prevention. We examined the current literature on TNPLP prevention in patients undergoing extremity amputation. A literature review was performed using Ovid Medline, Cochrane Collaboration Library, and Google Scholar to identify all original studies that addressed surgical prophylaxis against TNPLP. The search was conducted using both Medical Subject Headings and free-text using the terms “phantom limb pain,” “amputation neuroma,” and “surgical prevention of amputation neuroma.” Fifteen studies met the inclusion criteria, including six prospective trials, two comprehensive literature reviews, four retrospective chart reviews, and three case series/technique reviews. Five techniques were identified, and each was incorporated into a target-based classification system. A small but growing body of literature exists regarding the surgical prevention of TNPLP. Targeted muscle reinnervation (TMR), a form of physiologic target reassignment, has the greatest momentum in the academic surgical community, with multiple recent prospective studies demonstrating superior prevention of TNPLP. Neurorrhaphy and transposition with implantation are supported by less robust evidence, but merit future study as alternatives to TMR.

Research design considerations for chronic pain prevention clinical trials: IMMPACT recommendations

Although certain risk factors can identify individuals who are most likely to develop chronic pain, few interventions to prevent chronic pain have been identified. To facilitate the identification of preventive interventions, an IMMPACT meeting was convened to discuss research design considerations for clinical trials investigating the prevention of chronic pain. We present general design considerations for prevention trials in populations that are at relatively high risk for developing chronic pain. Specific design considerations included subject identification, timing and duration of treatment, outcomes, timing of assessment, and adjusting for risk factors in the analyses. We provide a detailed examination of 4 models of chronic pain prevention (ie, chronic postsurgical pain, postherpetic neuralgia, chronic low back pain, and painful chemotherapy-induced peripheral neuropathy). The issues discussed can, in many instances, be extrapolated to other chronic pain conditions. These examples were selected because they are representative models of primary and secondary prevention, reflect persistent pain resulting from multiple insults (ie, surgery, viral infection, injury, and toxic or noxious element exposure), and are chronically painful conditions that are treated with a range of interventions. Improvements in the design of chronic pain prevention trials could improve assay sensitivity and thus accelerate the identification of efficacious interventions. Such interventions would have the potential to reduce the prevalence of chronic pain in the population. Additionally, standardization of outcomes in prevention clinical trials will facilitate meta-analyses and systematic reviews and improve detection of preventive strategies emerging from clinical trials.

Paravertebral block for the prevention of chronic postsurgical pain after breast cancer surgery

Patients frequently report chronic postsurgical pain (CPSP) after breast cancer surgery (BCS). The paravertebral block (PVB) is an effective technique to reduce acute postoperative pain after BCS, but its efficacy in preventing CPSP is unclear. This meta-analysis evaluates the efficacy of PVB in preventing CPSP after BCS. We searched Medline, Embase, CENTRAL, Database of Abstracts of Reviews of Effects, ClinicalTrials.gov, and WHO International Clinical Trials Registry Platform for studies comparing PVB with control for CPSP prevention after BCS, from inception to April 2020. The primary outcome was CPSP at 6 months, and the secondary outcomes were CPSP at 3 and 12 months, chronic postsurgical neuropathic pain (CPSNP) at 6 months, and PVB-related complications. Data were pooled and analyzed with a random-effects model, and the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) system was used to evaluate the certainty of evidence. A total of 12 studies were included in the study; data for the 6-month time point from 7 studies (2161 patients) were analyzed, and no difference was found between PVB and control in terms of efficacy in preventing CPSP after BCS (risk ratio (RR) 0.82 (95% CI 0.62 to 1.08)), with a moderate quality of evidence according to the GRADE system. Similar results were obtained at 3 and 12 months (RR 0.78 (95% CI 0.57 to 1.06), RR 0.45 (95% CI 0.14 to 1.41), respectively). Data for the 12-month time point from seven studies (2087 patients) were analyzed and showed that PVB protected against CPSNP, with low quality of evidence (RR 0.51 (95% CI 0.31 to 0.85)). In conclusion, CPSP was not found significantly prevented by PVB after BCS despite the limits in the included studies; nevertheless, PVB could prevent CPSNP by impacting the transition from acute to chronic pain.

10-kHz Spinal Cord Stimulation for Chronic Postsurgical Pain: Results From a 12-Month Prospective, Multicenter Study

Background

Chronic postsurgical pain (CPSP) can be caused by peripheral nerve injury (PNI) resulting from surgical procedures and has a significant neuropathic component. This prospective, single‐arm study was conducted to document the effectiveness of 10‐kHz spinal cord stimulation (10‐kHz SCS) as a treatment for patients with CPSP.

Methods

Subjects with CPSP who were refractory to conventional medical interventions and reported pain scores of ≥5 cm on a 10‐cm VAS underwent trial stimulations lasting up to 14 days. Epidural leads were implanted at locations appropriate for the primary area of pain, and trials resulting in ≥40% pain relief were considered successful. Subjects with successful trials underwent implantation with a permanent 10‐kHz SCS system and were followed for 12 months after implantation.

Results

Of the 34 subjects who underwent trial stimulation, 1 was withdrawn early and 29 (87.9%) had a successful trial and received a permanent implant. After 12 months of treatment, the mean VAS score decreased by 6.5 cm, the response rate was 88.0% (22/25), and 18 subjects (62.1%) were remitters with VAS scores sustained at ≤3.0 cm. Scores for all components of the short‐form McGill Pain Questionnaire 2 were significantly reduced, including affective descriptors of pain. Pain catastrophizing and vigilance, patient function, physical and mental well‐being, and sleep quality all improved over the course of the study. No neurologic deficits reported in the study.

Conclusions

10‐kHz SCS is effective and tolerated in patients with CPSP, and further study of its clinical application in this population is warranted.

Medicaid insurance status predicts postoperative mortality after total knee arthroplasty in state inpatient databases

Aim: Medicaid versus private primary insurance status may predict in-hospital mortality and morbidity after total knee arthroplasty (TKA). Materials & methods: Regression models were used to test our hypothesis in patients in the State Inpatient Database (SID) from five states who underwent primary TKA from January 2007 to December 2014. Results: Medicaid patients had greater odds of in-hospital mortality (odds ratio [OR]: 1.73; 95% CI: 1.01-2.95), greater odds of any postoperative complications (OR: 1.25; 95% CI: 1.18-1.33), experience longer lengths of stay (OR: 1.09; 95% CI: 1.08-1.10) and higher total charges (OR: 1.03; 95% CI: 1.02-1.04). Conclusion: Medicaid insurance status is associated with higher in-hospital mortality and morbidity in patients after TKA compared with private insurance.

AAAPT Diagnostic Criteria for Acute Pain Following Breast Surgery

Acute pain after breast surgery decreases the quality of life of cancer survivors. Previous studies using a variety of definitions and methods report prevalence rates between 10% and 80%, which suggests the need for a comprehensive framework that can be used to guide assessment of acute pain and pain-related outcomes after breast surgery. A multidisciplinary task force with clinical and research expertise performed a focused review and synthesis and applied the 5 dimensional framework of the AAAPT (Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks [ACTTION], American Academy of Pain Medicine [AAPM], American Pain Society [APS] Pain Taxonomy) to acute pain after breast surgery. Application of the AAAPT taxonomy yielded the following: 1) Core Criteria: Location, timing, severity, and impact of breast surgery pain were defined; 2) Common Features: Character and expected trajectories were established in relevant surgical subgroups, and common pain assessment tools for acute breast surgery pain identified; 3) Modulating Factors: Biological, psychological, and social factors that modulate interindividual variability were delineated; 4) Impact/Functional Consequences: Domains of impact were outlined and defined; 5) Neurobiologic Mechanisms: Putative mechanisms were specified ranging from nerve injury, inflammation, peripheral and central sensitization, to affective and social processing of pain. PERSPECTIVE: The AAAPT provides a framework to define and guide improved assessment of acute pain after breast surgery, which will enhance generalizability of results across studies and facilitate meta-analyses and studies of interindividual variation, and underlying mechanism. It will allow researchers and clinicians to better compare between treatments, across institutions, and with other types of acute pain.

Benefit of regional anaesthesia on postoperative pain following mastectomy: the influence of catastrophising

BACKGROUND

Previous studies suggest that truncal regional anaesthesia (TRA), including techniques such as paravertebral block, may contribute significantly to analgesia after mastectomy. However, the severity and impact of postoperative pain varies markedly amongst individuals, making the identification of patients who would benefit most from TRA a potentially important step toward personalised perioperative care.

METHODS

In this prospective observational study, mastectomy patients (n=122) were recruited and systematically assessed for psychosocial characteristics including pain catastrophising before surgery, and either received preoperative TRA (n=57) or no block (n=65).

RESULTS

Age, baseline pain, and psychosocial traits did not differ between these groups. TRA was associated with lower overall pain scores and opioid consumption perioperatively, with a larger proportion of patients without block (50% vs 28%) reporting moderate-severe pain (more than three/10) on the day of surgery. Mixed model analysis of variance revealed a significant interaction between catastrophising and TRA, such that amongst patients with high baseline catastrophising, TRA was associated with substantially lower pain severity score (58% lower), while amongst patients with low baseline catastrophising, TRA was associated with only 18% lower pain severity. At 2 weeks, this interaction between baseline catastrophising and TRA was also observed when examining surgical pain burden, with higher baseline catastrophising patients who had received TRA reporting lower pain and less frequent opioid use (40% vs 70% of patients).

CONCLUSIONS

TRA provided immediate analgesic benefit for patients undergoing mastectomy on the day of surgery, but this effect appeared more pronounced and sustained amongst patients with higher baseline catastrophising.

CLINICAL TRIAL REGISTRATION

NCT02329574.

Erector spinae plane block for postoperative analgesia in patients undergoing total abdominal hysterectomy: a randomized controlled study original study

Background: Abdominal hysterectomy is associated with marked postoperative pain and morbidity, but effective postoperative analgesia provides early recovery and ambulation.

Aim: We intended to assess the efficacy of bilateral erector spinae plane block (ESPB) on postoperative analgesia in females undergoing abdominal hysterectomy under general anesthesia.

Settings and Design: The design was a prospective, randomized, controlled, single-blind clinical study.

Patients and Methods: Sixty patients with American Society of Anesthesiologists (ASA) physical status classes Ι to ΙΙΙ were scheduled for elective abdominal hysterectomy under general anesthesia, patients were randomly allocated into two equal groups. ESPB patients received ultrasound-guided ESPB at T9 vertebrae level with 20 ml bupivacaine 0.5%. Control group patients did not receive a block. Total fentanyl consumption in the first 24 h and visual analogue scale (VAS) score for pain were evaluated postoperatively. Unpaired Student’s t-tests, chi-square tests, and Z tests were used to compare groups.

Results: No significant differences were recorded between the groups regarding age, weight, ASA physical status, or surgery duration, Total fentanyl consumption in the first 24 h was significantly higher in the control group than the ESPB group (P=0.003; 485±20.39 mcg vs 445±67.49 mcg, respectively), VAS for pain was significantly higher in the control group for the first 12 h postoperatively.

Conclusions: Bilateral ESPB provided effective postoperative analgesia and markedly decreased postoperative fentanyl consumption in patients undergoing an abdominal hysterectomy.

Persistent postdischarge pain and chronic postoperative pain after breast cancer surgery under general anesthesia and single-shot paravertebral block: incidence, characteristics and impact on quality of life and healthcare costs

Introduction: Breast surgery is associated with persistent postsurgical pain; usually related to poorly treated acute pain. Paravertebral block has been successfully employed in analgesic protocols for breast surgery; its impact on postdischarge pain (PDP) has not been investigated. The aim of this study was to assess characteristics of PDP after breast surgery, the development of chronic postoperative pain (CPP) and its impact on health care costs.

Methods: We conducted a retrospective, observational study on a continuous cohort of adult female patients undergoing local breast cancer surgery under combined anesthesia. All patients were interviewed 6 months after hospital discharge. The survey was specifically conceived to assess incidence, features and duration of PDP. The overall cost of additional healthcare resources consumed with a specific relationship to persistent PDP was estimated.

Results: A database of 244 patients was preliminarily analyzed. Of these, 188 were included in the following statistical analysis; 123 patients (65.2%) reported significant PDP, with a median intensity on NRS of 6 (IQR=2), more frequently described as burning and associated with paresthesia and/or hyperalgesia (87 patients, 46%). One hundred and six patients (56.5%) reported this pain as interfering with their normal daily activities, work and sleep. In 26.8% of cases (50 patients) symptoms lasted more than 1 month and in 28 patients (15.0%) pain became chronic. The majority of patients self-treated their pain with non-steroideal anti-inflammatory drugs, but in 50 patients (26.8%) this therapy was reported as ineffective. This additional consumption of healthcare resources led to a significant economical impact.

Conclusion: PDP and CPP seem to be common complications after breast cancer surgery, even if a combined anesthesia technique with a thoracic paravertebral block is performed, leading to severe consequences on patients’ quality of life and increasing consumption of healthcare resources after discharge.

Trial number: NCT03618459 (www.clinicaltrials.gov).

Additional femoral nerve block analgesia does not reduce the chronic pain after total knee arthroplasty: A retrospective study in patients with knee osteoarthritis

Femoral nerve block analgesia was deemed to the gold standard for acute pain management after total knee arthroplasty (TKA). But effect on chronic pain management is not investigated fully. We conducted a retrospective study to explore the effect of single-injection femoral nerve block on postsurgical chronic pain.All medical records of patients undertaking TKA between January, 2013 and June, 2014 were reviewed via the Docare anesthesia database. Patients who administrated with the self-controlled intravenous analgesia were assigned to group P. Patients who received a single-injection femoral never block combined with patient self-controlled intravenous analgesia were assigned to group N + P. The visual analog scale (VAS) score before surgery, the first postoperative day (POD 1), POD 2, 3 months, 6 months, and 12 months after surgery were extracted from medical records. Pain score was compared over these 2 groups to investigate treatment outcomes.In all, 470 patients met the selection criteria for group P and 266 patients met the selection criteria for group N + P. Compared with group P, the VAS score decreased significantly in group N + P at POD 1 (P < .001), and the same was observed at POD 2 (P < .001); the moderate to severe pain incidence rate decreased significantly in group N + P at POD 1 (P < .01) and POD 2 (motion, P < .001). The rescued anesthesia rate reduced significantly in group N + P in POD 1 (P = .001), whereas no difference was found in POD 2 (P = .864). No difference was found at 3, 6, and 12 months after surgery (all P > .05).The single-injection femoral nerve block could relieve the acute postsurgical pain in a short period of time. But no evidence was found that it could reduce the chronic pain between 3 and 12 months after TKA.

Local anesthetics and regional anesthesia versus conventional analgesia for preventing persistent postoperative pain in adults and children: A Cochrane systematic review and meta-analysis update

BACKGROUND

Regional anesthesia may mitigate the risk of persistent postoperative pain (PPP). This Cochrane review, published originally in 2012, was updated in 2017.

METHODS

We updated our search of Cochrane CENTRAL, PubMed, EMBASE and CINAHL to December 2017. Only RCTs investigating local anesthetics (by any route) or regional anesthesia versus any combination of systemic (opioid or non-opioid) analgesia in adults or children, reporting any pain outcomes beyond three months were included. Data were extracted independently by at least two authors, who also appraised methodological quality with Cochrane 'Risk of bias' assessment and pooled data in surgical subgroups. We pooled studies across different follow-up intervals. As summary statistic, we reported the odds ratio (OR) with 95% confidence intervals and calculated the number needed to benefit (NNTB). We considered classical, Bayesian alternatives to our evidence synthesis. We explored heterogeneity and methodological bias.

RESULTS

40 new and seven ongoing studies, identified in this update, brought the total included RCTs to 63. We were only able to synthesize data from 39 studies enrolling 3027 participants in a balanced design. Evidence synthesis favored regional anesthesia for thoracotomy (OR 0.52 [0.32 to 0.84], moderate-quality evidence), breast cancer surgery (OR 0.43 [0.28 to 0.68], low-quality evidence), and cesarean section (OR 0.46, [0.28 to 0.78], moderate-quality evidence). Evidence synthesis favored continuous infusion of local anesthetic after breast cancer surgery (OR 0.24 [0.08 to 0.69], moderate-quality evidence), but was inconclusive after iliac crest bone graft harvesting (OR 0.20, [0.04 to 1.09], low-quality evidence).

CONCLUSIONS

Regional anesthesia reduces the risk of PPP. Small study size, performance, null, and attrition bias considerably weakened our conclusions. We cannot extrapolate to other interventions or to children.

In vitro and in vivo quantification of chloroprocaine release from an implantable device in a piglet postoperative pain model

Background

The pharmacokinetic properties and clinical advantages of the local anesthetic chloroprocaine are well known. Here, we studied the pharmacokinetic profile of a new hydrogel device loaded with chloroprocaine to investigate the potential advantages of this new strategy for postoperative pain (POP) relief.

Materials and methods

We performed both in vitro and in vivo analyses by considering plasma samples of four piglets receiving slow-release chloroprocaine. To quantify chloroprocaine and its inactive metabolite 4-amino-2-chlorobenzoic acid (ACBA), a HPLC–tandem mass spectrometry (HPLC-MS/MS) analytical method was used. Serial blood samples were collected over 108 hours, according to the exposure time to the device.

Results

Chloroprocaine was consistently found to be below the lower limit of quantification, even though a well-defined peak was observed in every chromatogram at an unexpected retention time. Concerning ACBA, we found detectable plasma concentrations between T₀ and T_12h, with a maximum plasma concentration (C_max) observed 3 hours after the device application. In the in vitro analyses, the nanogel remained in contact with plasma at 37°C for 90 minutes, 3 hours, 1 day, and 7 days. Chloroprocaine C_max was identified 1 day following exposure and C_min after 7 days, respectively. Additionally, ACBA reached the C_max following 7 days of exposure.

Conclusion

A thorough review of the literature indicates that this is the first study analyzing both in vivo and in vitro pharmacokinetic profiles of a chloroprocaine hydrogel device and is considered as a pilot study on the feasibility of including this approach to the management of POP.

A Systematic Review of Postoperative Pain Outcome Measurements Utilised in Regional Anesthesia Randomized Controlled Trials

INTRODUCTION

Regional anesthesia is a rapidly growing subspecialty. There are few published meta-analyses exploring pain outcome measures utilised in regional anesthesia randomized controlled trials (RCTs), which may be due to heterogeneity in outcomes assessed. This systematic review explores postoperative pain outcomes utilised in regional anesthesia RCTs.

METHODS

A literature search was performed using three databases (Medline, Embase, and CINAHL). Regional anesthesia RCTs with postoperative pain as a primary outcome were included if written in English and published in one of the top 20 impact factor journals between 2005 and 2017. Study quality was assessed using the Cochrane Collaboration's tool for assessing risk of bias.

RESULTS

From the 31 included articles, 15 different outcome measures in total were used to assess postoperative pain. The most commonly (16/31) used outcome measures were verbal numerical grading of pain out of 10, total opioid consumption, and visual analogue scale 10 cm (VAS). The need for analgesia was used as an outcome measure where studies did not use a pain rating score. Ten studies reported pain scores on activity and 27/31 studies utilised ≥2 pain outcomes. Time of measurement of pain score also varied with a total of 51 different time points used in total.

CONCLUSION

Analysis of the articles demonstrated heterogeneity and inconsistency in choice of pain outcome and time of measurement within regional anesthesia studies. Identification of these pain outcomes utilised can help to create a definitive list of core outcomes, which may guide future researchers when designing such studies.

Local anaesthetics and regional anaesthesia versus conventional analgesia for preventing persistent postoperative pain in adults and children

BACKGROUND

Regional anaesthesia may reduce the rate of persistent postoperative pain (PPP), a frequent and debilitating condition. This review was originally published in 2012 and updated in 2017.

OBJECTIVES

To compare local anaesthetics and regional anaesthesia versus conventional analgesia for the prevention of PPP beyond three months in adults and children undergoing elective surgery.

SEARCH METHODS

We searched CENTRAL, MEDLINE, and Embase to December 2016 without any language restriction. We used a combination of free text search and controlled vocabulary search. We limited results to randomized controlled trials (RCTs). We updated this search in December 2017, but these results have not yet been incorporated in the review. We conducted a handsearch in reference lists of included studies, review articles and conference abstracts. We searched the PROSPERO systematic review registry for related systematic reviews.

SELECTION CRITERIA

We included RCTs comparing local or regional anaesthesia versus conventional analgesia with a pain outcome beyond three months after elective, non-orthopaedic surgery.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed trial quality and extracted data and adverse events. We contacted study authors for additional information. We presented outcomes as pooled odds ratios (OR) with 95% confidence intervals (95% CI), based on random-effects models (inverse variance method). We analysed studies separately by surgical intervention, but pooled outcomes reported at different follow-up intervals. We compared our results to Bayesian and classical (frequentist) models. We investigated heterogeneity. We assessed the quality of evidence with GRADE.

MAIN RESULTS

In this updated review, we identified 40 new RCTs and seven ongoing studies. In total, we included 63 RCTs in the review, but we were only able to synthesize data on regional anaesthesia for the prevention of PPP beyond three months after surgery from 39 studies, enrolling a total of 3027 participants in our inclusive analysis.Evidence synthesis of seven RCTs favoured epidural anaesthesia for thoracotomy, suggesting the odds of having PPP three to 18 months following an epidural for thoracotomy were 0.52 compared to not having an epidural (OR 0.52 (95% CI 0.32 to 0.84, 499 participants, moderate-quality evidence). Simlarly, evidence synthesis of 18 RCTs favoured regional anaesthesia for the prevention of persistent pain three to 12 months after breast cancer surgery with an OR of 0.43 (95% CI 0.28 to 0.68, 1297 participants, low-quality evidence). Pooling data at three to 8 months after surgery from four RCTs favoured regional anaesthesia after caesarean section with an OR of 0.46, (95% CI 0.28 to 0.78; 551 participants, moderate-quality evidence). Evidence synthesis of three RCTs investigating continuous infusion with local anaesthetic for the prevention of PPP three to 55 months after iliac crest bone graft harvesting (ICBG) was inconclusive (OR 0.20, 95% CI 0.04 to 1.09; 123 participants, low-quality evidence). However, evidence synthesis of two RCTs also favoured the infusion of intravenous local anaesthetics for the prevention of PPP three to six months after breast cancer surgery with an OR of 0.24 (95% CI 0.08 to 0.69, 97 participants, moderate-quality evidence).We did not synthesize evidence for the surgical subgroups of limb amputation, hernia repair, cardiac surgery and laparotomy. We could not pool evidence for adverse effects because the included studies did not examine them systematically, and reported them sparsely. Clinical heterogeneity, attrition and sparse outcome data hampered evidence synthesis. High risk of bias from missing data and lack of blinding across a number of included studies reduced our confidence in the findings. Thus results must be interpreted with caution.

AUTHORS' CONCLUSIONS

We conclude that there is moderate-quality evidence that regional anaesthesia may reduce the risk of developing PPP after three to 18 months after thoracotomy and three to 12 months after caesarean section. There is low-quality evidence that regional anaesthesia may reduce the risk of developing PPP three to 12 months after breast cancer surgery. There is moderate evidence that intravenous infusion of local anaesthetics may reduce the risk of developing PPP three to six months after breast cancer surgery.Our conclusions are considerably weakened by the small size and number of studies, by performance bias, null bias, attrition and missing data. Larger, high-quality studies, including children, are needed. We caution that except for breast surgery, our evidence synthesis is based on only a few small studies. On a cautionary note, we cannot extend our conclusions to other surgical interventions or regional anaesthesia techniques, for example we cannot conclude that paravertebral block reduces the risk of PPP after thoracotomy. There are seven ongoing studies and 12 studies awaiting classification that may change the conclusions of the current review once they are published and incorporated.

Local anaesthetics and regional anaesthesia versus conventional analgesia for preventing persistent postoperative pain in adults and children

BACKGROUND

Regional anaesthesia may reduce the rate of persistent postoperative pain (PPP), a frequent and debilitating condition. This review was originally published in 2012 and updated in 2017.

OBJECTIVES

To compare local anaesthetics and regional anaesthesia versus conventional analgesia for the prevention of PPP beyond three months in adults and children undergoing elective surgery.

SEARCH METHODS

We searched CENTRAL, MEDLINE, and Embase to December 2016 without any language restriction. We used a combination of free text search and controlled vocabulary search. We limited results to randomized controlled trials (RCTs). We updated this search in December 2017, but these results have not yet been incorporated in the review. We conducted a handsearch in reference lists of included studies, review articles and conference abstracts. We searched the PROSPERO systematic review registry for related systematic reviews.

SELECTION CRITERIA

We included RCTs comparing local or regional anaesthesia versus conventional analgesia with a pain outcome beyond three months after elective, non-orthopaedic surgery.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed trial quality and extracted data and adverse events. We contacted study authors for additional information. We presented outcomes as pooled odds ratios (OR) with 95% confidence intervals (95% CI), based on random-effects models (inverse variance method). We analysed studies separately by surgical intervention, but pooled outcomes reported at different follow-up intervals. We compared our results to Bayesian and classical (frequentist) models. We investigated heterogeneity. We assessed the quality of evidence with GRADE.

MAIN RESULTS

In this updated review, we identified 40 new RCTs and seven ongoing studies. In total, we included 63 RCTs in the review, but we were only able to synthesize data on regional anaesthesia for the prevention of PPP beyond three months after surgery from 41 studies, enrolling a total of 3143 participants in our inclusive analysis.Evidence synthesis of seven RCTs favoured epidural anaesthesia for thoracotomy, suggesting the odds of having PPP three to 18 months following an epidural for thoracotomy were 0.52 compared to not having an epidural (OR 0.52 (95% CI 0.32 to 0.84, 499 participants, moderate-quality evidence). Simlarly, evidence synthesis of 18 RCTs favoured regional anaesthesia for the prevention of persistent pain three to 12 months after breast cancer surgery with an OR of 0.43 (95% CI 0.28 to 0.68, 1297 participants, low-quality evidence). Pooling data at three to 8 months after surgery from four RCTs favoured regional anaesthesia after caesarean section with an OR of 0.46, (95% CI 0.28 to 0.78; 551 participants, moderate-quality evidence). Evidence synthesis of three RCTs investigating continuous infusion with local anaesthetic for the prevention of PPP three to 55 months after iliac crest bone graft harvesting (ICBG) was inconclusive (OR 0.20, 95% CI 0.04 to 1.09; 123 participants, low-quality evidence). However, evidence synthesis of two RCTs also favoured the infusion of intravenous local anaesthetics for the prevention of PPP three to six months after breast cancer surgery with an OR of 0.24 (95% CI 0.08 to 0.69, 97 participants, moderate-quality evidence).We did not synthesize evidence for the surgical subgroups of limb amputation, hernia repair, cardiac surgery and laparotomy. We could not pool evidence for adverse effects because the included studies did not examine them systematically, and reported them sparsely. Clinical heterogeneity, attrition and sparse outcome data hampered evidence synthesis. High risk of bias from missing data and lack of blinding across a number of included studies reduced our confidence in the findings. Thus results must be interpreted with caution.

AUTHORS' CONCLUSIONS

We conclude that there is moderate-quality evidence that regional anaesthesia may reduce the risk of developing PPP after three to 18 months after thoracotomy and three to 12 months after caesarean section. There is low-quality evidence that regional anaesthesia may reduce the risk of developing PPP three to 12 months after breast cancer surgery. There is moderate evidence that intravenous infusion of local anaesthetics may reduce the risk of developing PPP three to six months after breast cancer surgery.Our conclusions are considerably weakened by the small size and number of studies, by performance bias, null bias, attrition and missing data. Larger, high-quality studies, including children, are needed. We caution that except for breast surgery, our evidence synthesis is based on only a few small studies. On a cautionary note, we cannot extend our conclusions to other surgical interventions or regional anaesthesia techniques, for example we cannot conclude that paravertebral block reduces the risk of PPP after thoracotomy. There are seven ongoing studies and 12 studies awaiting classification that may change the conclusions of the current review once they are published and incorporated.

Economic Considerations of Acute Pain Medicine Programs

Acute pain medicine services influence many different aspects of postoperative recovery and function. Here, we discuss the various stakeholders of an acute pain medicine service, review the direct and indirect impact on said stakeholders, review the shared and competing interests between acute pain medicine programs and various payer systems, and discuss how APM services can help service lines align with the interests of the recent CMS Innovations Comprehensive Care for Joint Replacement Model.

Does perioperative ketamine have a role in the prevention of chronic postsurgical pain: the ROCKet trial

Identifying operations and individuals with an increased risk of chronic postsurgical pain (CPSP) has led to significant interest in interventions with the potential to achieve primary prevention of this condition. Pharmacological prevention remains controversial with a Cochrane review identifying perioperative ketamine administration as the only intervention with possible benefit although, with only small, heterogeneous studies, the authors called for a large randomised controlled trial (RCT) to confirm the validity of this result. In response to these data, a group of researchers from Australia and Hong Kong designed the ROCKet trial - Reduction Of Chronic Post-surgical Pain with Ketamine, endorsed by the Australian and New Zealand College of Anaesthetists (ANZCA) Clinical Trials Network (CTN).

Poorly controlled postoperative pain: prevalence, consequences, and prevention

This review provides an overview of the clinical issue of poorly controlled postoperative pain and therapeutic approaches that may help to address this common unresolved health-care challenge. Postoperative pain is not adequately managed in greater than 80% of patients in the US, although rates vary depending on such factors as type of surgery performed, analgesic/anesthetic intervention used, and time elapsed after surgery. Poorly controlled acute postoperative pain is associated with increased morbidity, functional and quality-of-life impairment, delayed recovery time, prolonged duration of opioid use, and higher health-care costs. In addition, the presence and intensity of acute pain during or after surgery is predictive of the development of chronic pain. More effective analgesic/anesthetic measures in the perioperative period are needed to prevent the progression to persistent pain. Although clinical findings are inconsistent, some studies of local anesthetics and nonopioid analgesics have suggested potential benefits as preventive interventions. Conventional opioids remain the standard of care for the management of acute postoperative pain; however, the risk of opioid-related adverse events can limit optimal dosing for analgesia, leading to poorly controlled acute postoperative pain. Several new opioids have been developed that modulate μ-receptor activity by selectively engaging intracellular pathways associated with analgesia and not those associated with adverse events, creating a wider therapeutic window than unselective conventional opioids. In clinical studies, oliceridine (TRV130), a novel μ-receptor G-protein pathway-selective modulator, produced rapid postoperative analgesia with reduced prevalence of adverse events versus morphine.

Boundaries of the thoracic paravertebral space: potential risks and benefits of the thoracic paravertebral block from an anatomical perspective

Purpose

Thoracic paravertebral block (TPVB) may be an alternative to thoracic epidural analgesia. A detailed knowledge of the anatomy of the TPV-space (TPVS), content and adnexa is essential in understanding the clinical consequences of TPVB. The exploration of the posterior TPVS accessibility in this study allows (1) determination of the anatomical boundaries, content and adnexa, (2) description of an ultrasound-guided spread of low and high viscous liquid.

Methods

In two formalin-fixed specimens, stratification of the several layers and the 3D-architecture of the TPVS were dissected, observed and photographed. In a third unembalmed specimen, ultrasound-guided posterolateral injections at several levels of the TPVS were performed with different fluids.

Results

TPVS communicated with all surrounding spaces including the segmental dorsal intercostal compartments (SDICs) and the prevertebral space. TPVS transitions to the SDICs were wide, whereas the SDICs showed narrowed transitions to the lateral intercostal spaces at the costal angle. Internal subdivision of the TPVS in a subendothoracic and an extra-pleural compartment by the endothoracic fascia was not observed. Caudally injected fluids spread posteriorly to the costodiaphragmatic recess, showing segmental intercostal and slight prevertebral spread.

Conclusions

Our detailed anatomical study shows that TPVS is a potential space continuous with the SDICs. The separation of the TPVS in a subendothoracic and an extra-pleural compartment by the endothoracic fascia was not observed. Based on the ultrasound-guided liquid spread we conclude that the use of a more lateral approach might increase the probability of intravascular puncture or catheter position.

Can Chronic Pain Be Prevented?

All chronic pain begins at some discrete point in time. Significant strides in the understanding of mechanisms and risk factors associated with the transition from a new, or acute, pain experience to a chronic pain condition have been made over the past 20 years. These insights provide the hope of one day being able to modify or even halt this pathophysiologic progression. This article reviews some of the current knowledge of this transition as well as the evidence currently available to best prevent and treat it using persistent surgical pain as a model.

Continuous intraoperative epidural infusions affect recovery room length of stay and analgesic requirements: a single-center observational study

PURPOSE

Continuous intraoperative epidural analgesia may improve post-operative pain control and decrease opioid requirements. We investigate the effect of epidural infusion initiation before or after arrival in the post-anesthesia care unit on recovery room duration and post-operative opioid use.

METHODS

We performed a retrospective chart review of abdominal, thoracic and orthopedic surgeries where an epidural catheter was placed prior to surgery at the University of Washington Medical Center during a 24 month period.

RESULTS

Patients whose epidural infusions were started prior to PACU arrival (Group 2: n = 540) exhibited a shorter PACU length of stay (p = .004) and were less likely to receive intravenous opioids in the recovery room (34 vs. 48%; p < .001) compared to patients whose infusions were started after surgery (Group 1: n = 374). Although the highest patient-reported pain scores were lower in Group 2 (5.3 vs. 6.0; p = .030), no differences in the pain scores prior to PACU discharge were observed.

CONCLUSION

Intraoperative continuous epidural infusions decrease PACU LOS as discharge criteria for patient-reported NRS pain scores are met earlier.

[Trial sequential analysis : Sample size calculation for reliable meta-analyses]

BACKGROUND

Meta-analyses have a great impact on medical decision-making. Random errors are, however, often the reason for misinterpretation of interventional effects in meta-analyses.

OBJECTIVE

The aim of this article is to introduce authors and readers of meta-analyses to the problem of random errors. The article presents trial sequential analysis (TSA) as a suitable and user-friendly method that adjusts for the risk of random errors in meta-analyses.

MATERIAL AND METHODS

The practical application of TSA is illustrated and exemplified using regional anesthesiology procedures versus conventional pain therapy with respect to the prevention of persistent postoperative pain after breast cancer surgery or thoracotomy. The results were compared with those from conventional meta-analytical methods.

RESULTS

Conventional meta-analytical methods showed a significant advantage for patients after breast cancer surgery as well as after thoracotomy for regional anesthesia procedures with respect to the reduction of persistent postoperative pain. By means of TSA it could be concluded for thoracotomy that the evidence of this meta-analysis was sufficient. In contrast, the TSA for breast cancer surgery showed that based on the current data set and on the basis of relevant assumptions, it is potentially a false indication of an effect. There is currently no evidence that regional anesthesia leads to a significant reduction of persistent postoperative pain.

CONCLUSION

The TSA is a suitable tool to minimize the risk of random errors and for a more reliable assessment of the evidence for the results of a meta-analysis.

[Neuraxial anaesthesia and NOACs]

BACKGROUND

Cardiovascular comorbidities in surgical patients are frequent and have a substantial impact on the postoperative outcome. Neuraxial blockades are able to reduce perioperative morbidity and mortality. The increasing use of new oral anticoagulants (NOAC) requires a high level of attention, especially in patients undergoing neuraxial blockades or requiring postoperative analgesia.

OBJECTIVE

The goal of this article is to present the benefit of neuraxial anaesthesia and analgesia in patients with cardiovascular risks and perioperative management of NOAC in this setting.

MATERIALS AND METHODS

Review of the respective literature in PubMed during the last 25 years as well as presentation of the S1 guideline "Neuraxial anaesthesia and thrombo-embolic prophylaxis/antithrombotic medication" of the German Society of Anaesthesiology and Intensive Care Medicine (DGAI).

RESULTS

Thoracic epidural anaesthesia and analgesia contribute to an improved outcome in surgical patients with high cardiovascular risk. In order to avoid severe complications in patients on NOACs undergoing neuraxial blockades the S1 guideline of the DGAI must be respected and close interdisciplinary consultations between anaesthetist, cardiologist and surgeon are mandatory.

CONCLUSION

In consideration of the respective guideline neuraxial blockades can be performed in cardiovascular risk patients on NOACs, since these techniques contribute to an improved postoperative outcome.

Preparation of novel biodegradable ropivacaine microspheres and evaluation of their efficacy in sciatic nerve block in mice

In this study, ropivacaine chitosan-loaded microspheres for subcutaneous administration were developed. The systems were characterized in terms of surface morphology, particle size, encapsulation efficiency, and in vitro release behavior. Results showed that the microspheres had drug loading rate of 7.3% and encapsulation efficiency of 91.2%, and their average diameter was 2.62±0.76 µm. The morphology study revealed that the microspheres are uniform monodispersed spheres and did not form aggregates in aqueous solution. It was clearly observed that the release profile of ropivacaine microspheres exhibited a biphasic pattern: the initial burst release within the first 2 hours and a following slower and sustained release over a long time. In vivo, a greater area under the plasma concentration–time curve from 0 to t (AUC_0–t) was obtained from the microspheres (4.27-fold), than from the injection group, which indicated that there was a significantly improved systemic exposure to ropivacaine. Pharmacodynamics result showed that preparing ropivacaine as microsphere preparation could not only extend the drug effect time but also decrease the administration dosage.

A Clinical Experimental Model to Evaluate Analgesic Effect of Remote Ischemic Preconditioning in Acute Postoperative Pain

This study aims to evaluate the viability of a clinical model of remote ischemic preconditioning (RIPC) and its analgesic effects. It is a prospective study with twenty (20) patients randomly divided into two groups: control group and RIPC group. The opioid analgesics consumption in the postoperative period, the presence of secondary mechanical hyperalgesia, the scores of postoperative pain by visual analog scale, and the plasma levels interleukins (IL-6) were evaluated. The tourniquet applying after spinal anesthetic block was safe, producing no pain for all patients in the tourniquet group. The total dose of morphine consumption in 24 hours was significantly lower in RIPC group than in the control group (p = 0.0156). The intensity analysis of rest pain, pain during coughing and pain in deep breathing, showed that visual analogue scale (VAS) scores were significantly lower in RIPC group compared to the control group: p = 0.0087, 0.0119, and 0.0015, respectively. There were no differences between groups in the analysis of presence or absence of mechanical hyperalgesia (p = 0.0704) and in the serum levels of IL-6 dosage over time (p < 0.0001). This clinical model of remote ischemic preconditioning promoted satisfactory analgesia in patients undergoing conventional cholecystectomy, without changing serum levels of IL-6.

From micro- to nanostructured implantable device for local anesthetic delivery

Local anesthetics block the transmission of painful stimuli to the brain by acting on ion channels of nociceptor fibers, and find application in the management of acute and chronic pain. Despite the key role they play in modern medicine, their cardio and neurotoxicity (together with their short half-life) stress the need for developing implantable devices for tailored local drug release, with the aim of counterbalancing their side effects and prolonging their pharmacological activity. This review discusses the evolution of the physical forms of local anesthetic delivery systems during the past decades. Depending on the use of different biocompatible materials (degradable polyesters, thermosensitive hydrogels, and liposomes and hydrogels from natural polymers) and manufacturing processes, these systems can be classified as films or micro- or nanostructured devices. We analyze and summarize the production techniques according to this classification, focusing on their relative advantages and disadvantages. The most relevant trend reported in this work highlights the effort of moving from microstructured to nanostructured systems, with the aim of reaching a scale comparable to the biological environment. Improved intracellular penetration compared to microstructured systems, indeed, provides specific drug absorption into the targeted tissue and can lead to an enhancement of its bioavailability and retention time. Nanostructured systems are realized by the modification of existing manufacturing processes (interfacial deposition and nanoprecipitation for degradable polyester particles and high- or low-temperature homogenization for liposomes) or development of novel strategies (electrospun matrices and nanogels). The high surface-to-volume ratio that characterizes nanostructured devices often leads to a burst drug release. This drawback needs to be addressed to fully exploit the advantage of the interaction between the target tissues and the drug: possible strategies could involve specific binding between the drug and the material chosen for the device, and a multiscale approach to reach a tailored, prolonged drug release.

Regional versus general anaesthesia for improved cognitive function after procedures other than cardiac surgery or neurosurgery in adult and paediatric patients

This is the protocol for a review and there is no abstract. The objectives are as follows: The objective of this review is to compare the effects of regional versus general anaesthesia on cognitive function after procedures other than cardiac surgery or neurosurgery in adult and in paediatric patients.

Interventional options for the management of refractory cancer pain--what is the evidence?

PURPOSE

Pain is the most common symptom in cancer patients. Standard pain treatment according to the WHO three-step analgesic ladder provides effective pain management in approximately 70-90% of cancer patients. Refractory pain is defined as not responding to "standard" treatments. Interventional analgesic techniques can be used in an attempt to control refractory pain in patients in whom conventional analgesic strategies fail to provide effective pain relief or are intolerable due to severe adverse effects. This systematic review aims to provide the latest evidence on interventional refractory pain management in cancer patients.

METHODS

Systematic literature search in Cochrane, EMBASE and PubMed including reviews and randomised controlled trials (RCTs) and non-randomised controlled trials in the absence of reviews.

RESULTS

Neuraxial analgesia may play a role in refractory cancer pain management. Paravertebral blocks decrease the incidence of persistent post-surgical pain after breast cancer. Coeliac plexus blocks improve pain scores in refractory pancreatic cancer pain for up to 4 weeks after the intervention with fewer burdensome side effects as compared to opioids. Cordotomy has mainly been studied in mesothelioma, and the case series suggest possible benefit for pain at the expense of a relatively high risk of side effects.

CONCLUSIONS

Overall, very few RCTs have been conducted on interventional pain techniques. In reality, it is very difficult to undertake large controlled trials for a number of reasons. Therefore, today's best evidence for practice may be from large case series of comparable patients with careful response and toxicity evaluation and follow-up.

A Prospective Multicentre Study to Improve Postoperative Pain: Identification of Potentialities and Problems

Many studies still indicate insufficient pain management after surgery, e.g., in patients after small- or medium-size operations. Yet it is still uncertain if postoperative pain based on patient-related outcomes can be improved by implementing guideline-related programmes in a multicentre approach. Adult patients in six hospitals in one German city were included in this prospective study. Data collection took place twice in each hospital, once before and once after implementation of concepts and in-house training. Pain and pain-related aspects were assessed one day after surgery and compared between the pre- and post-test group including subgroup analysis of certain surgical procedures by using Student’s t-tests, Mann-Whitney U tests and chi-square tests (alpha_two-tailed = 0.05). Overall, pain at rest and during movement was slightly lower after the intervention. Significant changes were observed after thoracic surgery, small joint surgery and other minor surgical procedures. The rather moderate decrease in pain likely relates to a reasonable pre-existing pain management and to detached improvements in certain patient subgroups. Interestingly, specific analyses revealed significantly lower post-test pain as compared to pre-test pain only in patients without pre-existing chronic pain. Side effects related to pain medication were significantly lower after intervention. Our data show, for the first time, benefits of a perioperative teaching programme in a multicentre approach. Pain ratings improved mainly in specific subgroups of patients, e.g., small surgical procedures and patients without preoperative pain. Thus, general improvement is possible but special attention should be paid to the group of patients with preoperative pain.

Regional analgesia for improvement of long-term functional outcome after elective large joint replacement

BACKGROUND

Regional analgesia is more effective than conventional analgesia for controlling pain and may facilitate rehabilitation after large joint replacement in the short term. It remains unclear if regional anaesthesia improves functional outcomes after joint replacement beyond three months after surgery.

OBJECTIVES

To assess the effects of regional anaesthesia and analgesia on long-term functional outcomes 3, 6 and 12 months after elective major joint (knee, shoulder and hip) replacement surgery.

SEARCH METHODS

We performed an electronic search of several databases (CENTRAL, MEDLINE, EMBASE, CINAHL), and handsearched reference lists and conference abstracts. We updated our search in June 2015.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) comparing regional analgesia versus conventional analgesia in patients undergoing total shoulder, hip or knee replacement. We included studies that reported a functional outcome with a follow-up of at least three months after surgery.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We contacted study authors for additional information.

MAIN RESULTS

We included six studies with 350 participants followed for at least three months. All of these studies enrolled participants undergoing total knee replacement. Studies were at least partially blinded. Three studies had a high risk of performance bias and one a high risk of attrition bias, but the risk of bias was otherwise unclear or low.Only one study assessed joint function using a global score. Due to heterogeneity in outcome and reporting, we could only pool three out of six RCTs, with range of motion assessed at three months after surgery used as a surrogate for joint function. All studies had a high risk of detection bias. Using the random-effects model, there was no statistically significant difference between the experimental and control groups (mean difference 3.99 degrees, 95% confidence interval (CI) - 2.23 to 10.21; P value = 0.21, 3 studies, 140 participants, very low quality evidence).We did not perform further analyses because immediate adverse effects were not part of the explicit outcomes of any of these typically small studies, and long-term adverse events after regional anaesthesia are rare.None of the included studies elicited or reported long-term adverse effects like persistent nerve damage.

AUTHORS' CONCLUSIONS

More high-quality studies are needed to establish the effects of regional analgesia on function after major joint replacement, as well as on the risk of adverse events (falls).

Acupuncture for the treatment of phantom limb pain in lower limb amputees: study protocol for a randomized controlled feasibility trial

BACKGROUND

Phantom limb pain is a prevalent condition that is difficult to manage, with a lack of robust evidence to support the use of many adjunctive treatments. Acupuncture can be effective in the management of many painful conditions but little is known about its effectiveness in treating phantom limb pain. The aim of this study is to explore the feasibility of conducting a randomized controlled trial comparing acupuncture and routine care in a group of lower limb amputees with phantom limb pain.

METHODS/DESIGN

An unstratified, pragmatic, randomized, two-armed, controlled trial of parallel design comparing acupuncture and usual care control will be conducted. A total of 20 participants will be randomly assigned to receive either usual care or usual care plus acupuncture. Acupuncture will include eight 1 hour treatments delivered pragmatically over 4 weeks by practitioners trained in traditional Chinese medicine. As outcome measures, the Numerical Pain Rating Scale, short-form McGill Pain Questionnaire 2, EQ-5D-5 L, Hospital Anxiety and Depression Scale, 10-Item Perceived Stress Scale, Insomnia Severity Index, and Patient Global Impression of Change will be completed at baseline, weekly for the duration of the study and at 1 month after completion of the study. After completion of the trial, participants will provide feedback though semi-structured interviews. Feasibility will be determined through the ability to recruit to the study, success of the randomization process, completion of acupuncture intervention, acceptability of random allocation and completion of outcome measures. Acceptability of the acupuncture intervention will be determined through semi-structured interviews with participants. The appropriateness of outcome measures for a future trial will be addressed through completion rates of questionnaires and participant feedback.

DISCUSSION

Data generated on effect size will be used for future sample size calculations and will inform the development of an appropriate and feasible protocol for use in a definitive multicentre randomized controlled trial.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02126436.

Intra- and postoperative intravenous ketamine does not prevent chronic pain: A systematic review and meta-analysis

Background and aims

The development of postoperative chronic pain (POCP) after surgery is a major problem with a considerable socioeconomic impact. It is defined as pain lasting more than the usual healing, often more than 2–6 months. Recent systematic reviews and meta-analyses demonstrate that the N-methyl-D-aspartate-receptor antagonist ketamine given peri- and intraoperatively can reduce immediate postoperative pain, especially if severe postoperative pain is expected and regional anaesthesia techniques are impossible. However, the results concerning the role of ketamine in preventing chronic postoperative pain are conflicting. The aim of this study was to perform a systematic review and a pooled analysis to determine if peri- and intraoperative ketamine can reduce the incidence of chronic postoperative pain.

Methods

Electronic searches of PubMed, EMBASE and Cochrane including data until September 2013 were conducted. Subsequently, the titles and abstracts were read, and reference lists of reviews and retrieved studies were reviewed for additional studies. Where necessary, authors were contacted to obtain raw data for statistical analysis. Papers reporting on ketamine used in the intra- and postoperative setting with pain measured at least 4 weeks after surgery were identified. For meta-analysis of pain after 1, 3, 6 and 12 months, the results were summarised in a forest plot, indicating the number of patients with and without pain in the ketamine and the control groups. The cut-off value used for the VAS/NRS scales was 3 (range 0–10), which is a generally well-accepted value with clinical impact in view of quality of life.

Results

Our analysis identified ten papers for the comprehensive meta-analysis, including a total of 784 patients. Three papers, which included a total of 303 patients, reported a positive outcome concerning persistent postsurgical pain. In the analysis, only one of nine pooled estimates of postoperative pain at rest or in motion after 1, 3, 6 or 12 months, defined as a value ≥3 on a visual analogue scale of 0–10, indicated a marginally significant pain reduction.

Conclusions

Based on the currently available data, there is currently not sufficient evidence to support a reduction in chronic pain due to perioperative administration of ketamine. Only the analysis of postoperative pain at rest after 1 month resulted in a marginally significant reduction of chronic postoperative pain using ketamine in the perioperative setting.

Implications

It can be hypothesised, that regional anaesthesia in addition to the administration of perioperative ketamine might have a preventive effect on the development of persistent postsurgical pain. An additional high-quality pain relief intra- and postoperatively as well after discharge could be more effective than any particular analgesic method per se. It is an assumption that a low dose infusion ketamine has to be administered for more than 72 h to reduce the risk of chronic postoperative pain.

Perineural steroids for trauma and compression-related peripheral neuropathic pain: a systematic review and meta-analysis

PURPOSE

Perineural steroids are often used to treat chronic peripheral neuropathic pain (NP) secondary to trauma or compression. Nevertheless, when compared with local anesthetics (LA) or conventional medical management (CMM), their efficacy and safety in patients with trauma or compression-related neuropathic pain syndromes is unclear. The purpose of this systematic review and meta-analysis was to determine the efficacy and safety of perineural steroids in compression or trauma-related NP after one to three months of injection.

SOURCE

We reviewed randomized controlled trials from MEDLINE(®), EMBASE™, Cochrane central register of controlled trials, Cochrane database of systematic reviews, and Google Scholar (first 200 hits) up to April 2014 that compared perineural injections of steroids with LA or CMM in adult patients with trauma or compression-related chronic peripheral NP. A meta-analysis was performed on the data on pain scores measured at one to three months after the interventions. Quality of evidence was classified using the GRADE system. Two authors independently reviewed all identified titles and abstracts for eligibility.

PRINCIPAL FINDINGS

Five trials comprising 353 patients (177 in the steroid group and 176 in the comparator groups) were included. At one to three months after the interventions, patients who received perineural steroids reported lower pain scores than those who received LA or CMM (mean difference: -1.31 points on a 0-10 numerical rating scale for pain; 95% confidence interval: -2.50 to -0.13; quality of evidence: low; I(2) = 89%). None of the studies reported any significant adverse effects.

CONCLUSIONS

Perineural steroids may provide analgesic efficacy for one to three months in patients with chronic peripheral NP of traumatic or compressive origin; however, the strength of this recommendation is weak. Well-designed large randomized studies are required.

Evidence-based anesthesia for major gynecologic surgery

Studies on enhanced recovery after gynecological surgery are limited but seem to report outcome benefits similar to those reported after colorectal surgery. Regional anesthesia is recommended in enhanced recovery protocols. Effective regional anesthetic techniques in gynecologic surgery include spinal anesthesia, epidural analgesia, transversus abdominis plane blocks, local anesthetic wound infusions and intraperitoneal instillation catheters. Non-opioid analgesics including pregabalin, gabapentin, NSAIDs, COX-2 inhibitors, and paracetamol reduce opioid consumption after surgery. This population is at high risk for PONV, thus, a multimodal anti-emetic strategy must be employed, including strategies to reduce the baseline risk of PONV in conjunction with combination antiemetic therapy.

Study protocol for a double blind, randomised, placebo-controlled trial of continuous subpectoral local anaesthetic infusion for pain and shoulder function following mastectomy: SUB-pectoral Local anaesthetic Infusion following MastEctomy (SUBLIME) study

INTRODUCTION

Over 16 000 mastectomies are performed in England and Wales annually. Acute postoperative pain and nausea are common. The most frequently occurring long-term complications are chronic pain (up to 50%) and reduced shoulder function (reported at 35%). Regional techniques that improve acute postoperative pain relief may reduce the incidence of these complications. This study assesses the effectiveness of a 24-hour continuous local anaesthetic in the subpectoral plane in improving postoperative pain and quality of life in patients undergoing mastectomy.

METHODS AND ANALYSIS

This is a randomised, double blind, placebo-controlled, two-centre, parallel group trial in women undergoing mastectomy with or without axillary involvement. One hundred and sixty participants will be randomised in a 1:1 ratio to receive either 0.25% levobupivacaine or 0.9% saline by subpectoral infusion postoperatively for 24 h. All participants will be provided with an intravenous morphine patient-controlled analgesia (PCA) system. Participants will be followed-up for 24 h in hospital and at approximately 14 days and 6 months postoperatively. Joint primary outcome measures are total morphine consumption and total pain score (captured via patient-recorded visual analogue scale (VAS) 4 hourly) during the first 24 h postoperatively. Primary statistical analysis of total pain is based on the area under the curve of pain versus time graph. Secondary outcomes include PCA attempts in first 24 h; VAS pain scores and shoulder function by goniometry at 24 h, 14 days (approximately) and 6 months; Verbal Rating Scale pain scores in first 24 h; Brief Pain Inventory and Oxford Shoulder Score at 6 months; duration of hospital stay; incidence of postoperative nausea and vomiting; cost-effectiveness.

ETHICS AND DISSEMINATION

The study is approved by the South West England Research Ethics Committee (12/SW/0149).

RESULTS

will be published in a peer-reviewed journal and presented at local, national and international scientific meetings.

TRIAL REGISTRATION

ISRCTN46621916. EudraCT 2011-005775-16.

Local anesthetic systemic toxicity

Local anesthetic systemic toxicity (LAST) is a rare yet devastating complication from the administration of local anesthesia. The ability to recognize and treat LAST is critical for clinicians who administer these drugs. The authors reviewed the literature on the mechanism, treatment, and prevention of LAST, with the goal of proposing a practical method for its management.

A comparison of the analgesia efficacy and side effects of paravertebral compared with epidural blockade for thoracotomy: an updated meta-analysis

Objective

The most recent systematic review and meta-analysis comparing the analgesic efficacy and side effects of paravertebral and epidural blockade for thoracotomy was published in 2006. Nine well-designed randomized trials with controversial results have been published since then. The present report constitutes an updated meta-analysis of this issue.

Summary of Background

Thoracotomy is a major surgical procedure and is associated with severe postoperative pain. Epidural analgesia is the gold standard for post-thoracotomy pain management, but has its limitations and contraindications, and paravertebral blockade is increasingly popular. However, it has not been decided whether the analgesic effect of the two methods is comparable, or whether paravertebral blockade leads to a lower incidence of adverse side effects after thoracotomy.

Methods

Two reviewers independently searched the databases PubMed, EMBASE, and the Cochrane Library (last performed on 1 February, 2013) for reports of studies comparing post-thoracotomy epidural analgesia and paravertebral blockade. The same individuals independently extracted data from the appropriate studies.

Result

Eighteen trials involving 777 patients were included in the current analysis. There was no significant difference in pain scores between paravertebral blockade and epidural analgesia at 4–8, 24, 48 hours, and the rates of pulmonary complications and morphine usage during the first 24 hours were also similar. However, paravertebral blockade was better than epidural analgesia in reducing the incidence of urinary retention (p<0.0001), nausea and vomiting (p = 0.01), hypotension (p<0.00001), and rates of failed block were lower in the paravertebral blockade group (p = 0.01).

Conclusions

This meta-analysis showed that PVB can provide comparable pain relief to traditional EPI, and may have a better side-effect profile for pain relief after thoracic surgery. Further high-powered randomized trials are to need to determine whether PVB truly offers any advantages over EPI.