The effect of pregabalin on acute postoperative pain in patients undergoing total knee arthroplasty: A meta-analysis

Duloxetine reduces opioid consumption and pain after total hip or knee arthroplasty: a meta-analysis of randomized controlled trials

PURPOSE

There is no consensus in the current literature on the analgesic role of duloxetine after total hip arthroplasty (THA) or total knee arthroplasty (TKA). Thus, we designed this meta-analysis to reveal the analgesic effectiveness and safety of duloxetine in TKA or THA.

METHODS

As of October 2022, two authors (L.C. and W.Q.J.) independently searched five main databases (EMBASE, Web of Science, PubMed, Cochrane Library, and Google Scholar) to find relevant studies. Duloxetine vs. placebo in randomized controlled trials (RCTs) for THA or TKA were included. We set perioperative total opioid consumption as the primary outcome. Secondary outcomes included resting or dynamic pain scores over time, gastrointestinal adverse events, neurological adverse events, and other adverse reactions.

RESULTS

Eight RCTs with 695 patients were incorporated in our study. This meta-analysis showed high evidence that duloxetine was effective in reducing perioperative opioid consumption (Standard mean difference [SMD] = - 0.50, 95% confidence intervals [CI]: -0.70 to - 0.31, P < 0.00001) and low to moderate evidence that duloxetine could reduce pain within three weeks after surgery. Low to high evidence showed no differences between the two groups for most adverse events. Substantial evidence suggests that duloxetine can reduce nausea and vomiting after surgery (Risk ratio [RR] = 0.69, 95% CI: 0.50 to 0.95, P = 0.02, I2 = 4%). However, moderate evidence suggested that duloxetine might be associated with increased postoperative drowsiness (RR = 1.83, 95% CI: 1.08 to 3.09, P = 0.02, I2 = 0%).

CONCLUSION

Duloxetine reduced overall opioid consumption in the perioperative period and relieved pain within three weeks after surgery without increasing the risk of adverse drug events. Duloxetine can be part of a multimodal management regimen in patients with THA and TKA.

Cross-cultural adaptation and validation for central sensitization inventory: based on Chinese patients undergoing total knee arthroplasty for knee osteoarthritis

BACKGROUND

This study was conducted to develop a simplified Chinese version of the central sensitization inventory (CSI-CV) and to evaluate its reliability and validity.

METHODS

The CSI-CV was developed through a process involving the translation and back translation of the original CSI. Subsequently, experts reviewed and revised the content of the items to ensure their appropriateness. A total of 325 patients with knee osteoarthritis (KOA), who were scheduled to undergo total knee arthroplasty (TKA), completed the CSI-CV at a prominent orthopedic center in Xi'an, China. Afterward, a random selection of 100 participants was chosen for retesting after one week. The reliability and validity of the inventory were evaluated through exploratory factor analysis, correlation coefficient calculation and other methods.

RESULTS

The CSI-CV consists of 25 items in five dimensions (emotional distress, headache and jaw symptoms, physical symptoms, urological symptoms, and fatigue and sleep problems). The cumulative variance contribution rate was 75.3%, the Cronbach's α coefficient was 0.83, the Guttman split-half reliability coefficient was 0.88 and the intraclass correlation coefficient was 0.965. The CSI-CV scores correlated moderately with the total scores of the brief pain inventory (r = 0.506), Western Ontario and McMaster Universities Osteoarthritis Index (r = 0.466) and EuroQoL Group's five-dimension questionnaire (r = 0.576).

CONCLUSIONS

The findings demonstrate that the CSI was successfully trans-culturally adapted into a simplified Chinese version (CSI-CV) that was reliable and valid for Chinese-speaking patients who awaiting TKA for KOA.

The effect of pregabalin on postoperative pain after anterior cruciate ligament reconstruction: A systematic review of randomized clinical trials

Background

Despite the enormous success of anterior cruciate ligament (ACL) reconstruction, acute neuropathic pain can develop postoperatively and is both distressing and difficult to treat once established. Pregabalin, an anticonvulsant agent that selectively affects the nociceptive process, has been used as a pain relief agent. The purpose of this systematic review of randomized controlled trials (RCTs) was to evaluate the pain control effect of pregabalin versus placebo after ACL reconstruction.

Method

A search of the literature was performed from inception to June 2022, using PubMed, Scopus, Google Scholar, Web of Science, Cochrane and EBSCO. Studies considered for inclusion were RCTs that reported relevant outcomes (postoperative pain scores, cumulative opioid consumption, adverse events) following administration of pregabalin in patients undergoing ACL reconstruction.

Result

Five placebo-controlled RCTs involving 272 participants met the inclusion criteria. 75 mg and 150 mg oral pregabalin was used in included trials. Two studies used a single dose of pregabalin one hour before anesthesia induction. Two studies used pregabalin 1 hour before anesthesia induction and 12 hours after. One study used daily pregabalin 7 days before and 7 days after surgery. Out of five papers, three papers found significantly lower pain intensity and cumulative opioid consumption in pregabalin group compared with placebo group. However, a decrease in pain scores was found in all trials. Pregabalin administration was associated with dizziness and nausea.

Conclusion

The use of pregabalin may be a valuable asset in pain management after ACL reconstruction. However, future studies with larger sample size and longer follow-up period are required.

Perioperative Administration of Pregabalin and Esketamine to Prevent Chronic Pain After Breast Cancer Surgery: A Randomized Controlled Trial

Background

Perioperative multimodal analgesia can prevent chronic pain after breast cancer surgery. This study aimed to investigate the efficacy of combined perioperative oral pregabalin and postoperative esketamine in preventing chronic pain after breast cancer surgery.

Methods

Ninety patients undergoing elective breast cancer surgery were randomized into the combined pregabalin and esketamine group (EP group) and the general anesthesia alone group (Control group). The EP group received 150 mg of oral pregabalin 1 h before surgery and twice daily for seven days postoperatively, and a patient-controlled analgesia pump after surgery that delivered 100 μg sufentanil + 1.25 mg/kg esketamine + 4 mg tropisetron in 100 mL saline solution intravenously. The Control group received placebo capsules before and after the surgery and routine postoperative analgesia (100 μg sufentanil + 4 mg tropisetron in 100 mL saline solution). The primary outcome was the incidence of chronic pain three and six months after surgery. Secondary outcomes included acute postoperative pain, postoperative opioid consumption, and incidence of adverse events.

Results

The incidence of chronic pain in the EP group was significantly lower than in the Control group three (14.3% vs 46.3%, P = 0.005) and six (7.1% vs 31.7%, P = 0.009) months postoperatively. The rest numerical rating scale (NRS) pain scores 1-3 days postoperatively and coughing NRS pain scores 1-7 days postoperatively in the EP group were significantly lower than in the Control group (all P ˂ 0.05). The cumulative sufentanil consumption in the EP group during postoperative 0-12, 12-24, and 24-48, 0-24, and 0-48 hours were significantly lower than in the Control group (all P ˂ 0.05).

Conclusion

Combined perioperative oral pregabalin and postoperative esketamine effectively prevented chronic pain after breast cancer surgery, improved acute postoperative pain, and reduced postoperative opioid consumption.

Prevention of Pregabalin-Related Side Effects Using Slow Dose Escalation Before Surgery: A Trial in Primary Total Joint Arthroplasty Within the Enhanced Recovery After Surgery Pathway

BACKGROUND

The side effects of pregabalin likely occur after the first dose. We aimed to evaluate the effect of 75 milligrams (mg) of pregabalin prescribed as an initial dose with a slow dose escalation for primary total joint arthroplasty within the enhanced recovery after surgery pathway.

METHODS

Participants were randomly assigned to two groups. Fifty-eight patients were enrolled, and twenty-nine were assigned to each group. Group 1 (G1) received pregabalin (37.5 mg) twice on the day before surgery, as well as pregabalin 75 mg two hours pre-operatively; Group 2 (G2) received none on the day before surgery and the same dose of pregabalin at two hours pre-operatively. The primary outcome was dizziness assessed by severity; secondary outcomes included nausea, vomiting, sedation, opioid consumption, independent transfer at six hours post-operatively, time to readiness for independent transfers, time to readiness for discharge, and pain.

RESULTS

At two, four, and six hours post-operatively, the proportion of patients experiencing dizziness and nausea was significantly greater in G2 than in G1, and opioid consumption was significantly greater in G2 than in G1 (P = .012). The proportion of independent transfers at six hours post-operatively was significantly greater in G1 than in G2 (P = .010). The time to readiness for independent transfers was significantly shorter in G1 than in G2 (P = .016).

CONCLUSION

Prescription of pregabalin 37.5 mg twice on the day before surgery was effective in reducing early postoperative dizziness and nausea after receiving pregabalin 75 mg two hours pre-operatively. It also promoted early independent transfers and reduced opioid consumption.

A Meta-Analysis Showing the Quantitative Evidence Base of Preemptive Pregabalin for Postoperative Pain from Cancer-Related Surgery

Background and Objectives: As an adjunct to postoperative multimodal analgesic regimens, pregabalin has been reported in reducing postoperative acute pain and opioid consumption. However, there is only a small amount of evidence for preemptive pregabalin in patients undergoing cancer-related surgery. This systematic review was conducted to integrate high-quality evidence to evaluate the preemptive analgesic effects of pregabalin in cancer-related surgery. Materials and Methods: Seven electronic databases were searched in a combination of subject terms and free words. Efficacy and safety of preemptive pregabalin on postoperative pain for cancer-related surgery were evaluated by assessing resting and dynamic pain scores postoperatively, cumulative morphine equivalent consumption, time to first analgesic request, hemodynamic parameters, and the safety indicators. Results: Thirteen trials were incorporated for quantitative synthesis. The pooled results showed administration of pregabalin preoperatively is clinically significant for improving resting (weighted mean difference (WMD), -1.53 cm; 95% CI, -2.30 to -0.77) and dynamic (WMD, -1.16 cm; 95% CI, -2.22 to -0.11) pain severity scores at 2 h postoperatively and prolonging time to first analgesic request (WMD, 2.28 h; 95% CI, 0.79 to 3.77) in cancer-related surgery. Preemptive pregabalin was also statistically effective in some other pain indicators but would increase the risk of pregabalin-related side effects after surgery. Conclusions: Our findings do not support the administration of pregabalin in doses larger than 300 mg when put in cancer-related surgery. Taken together, more high-quality research particularly focused on the optimal dosages and timing of pregabalin in cancer-related surgery is needed in the future to establish stronger evidence for therapeutic effects.

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.

Opioid-free shoulder arthroplasty is safe, effective, and predictable compared with a traditional perioperative opiate regimen: a randomized controlled trial of a new clinical care pathway

BACKGROUND

Opiate-based regimens have been used as a foundation of postoperative analgesia in orthopedic surgery for decades, and the vast majority of orthopedic patients in the United States receive postoperative opioid prescriptions. Both the safety and efficacy of opioid use in orthopedic patients have been questioned because of mounting evidence that postoperative opioid use can be detrimental to outcomes and patient satisfaction. The purpose of this study is to compare a new, opioid-free pain management pathway with a traditional opioid-containing, multimodal pathway in patients undergoing shoulder arthroplasty.

METHODS

This is a single-center randomized clinical trial in which 67 patients who underwent shoulder arthroplasty were allocated into 2 treatment arms: either a completely opioid-free, multimodal perioperative pain management pathway (OF), or a traditional opioid-containing perioperative pain management pathway (OC). Pain was measured on a numeric rating scale from 0 to 10 at 6-, 12-, 24-hour, 2-week, and 6-week time points. Deviations from the OF pathway, morphine milligram equivalents, readmissions, and opioid-related side effects were analyzed.

RESULTS

Pain levels were significantly lower in the OF group at 12 hours, 24 hours, and 2 weeks. At 12 hours, the median pain rating was 0 compared with a median pain rating of 3 in the OC group (P = .003). At 24 hours, the OF group reported a median pain rating of 1 and the OC group reported a median pain rating of 4 (P < .001). The median pain rating at the 2-week time point in the OF group was 2 compared with 4 in the OC group (P = .006). Median pain ratings were similar between the OF group and the OC group at the 6-week time point. The median pain rating in the OF group at 6 weeks was 1, compared with 1.5 in the OC group. Of the 35 patients in the OF pathway, 1 required a rescue opioid medication for left cervical radiculopathy that ultimately necessitated cervical spine fusion after recovery from right shoulder arthroplasty, and 1 was noted to have taken an opioid medication, diverted from a prior prescription, at the 2-week visit. The morphine milliequivalents received in the OF group was 20 compared with 4936.25 in the OC group. There were no readmissions in the OF pathway, and no differences between the groups with regard to constipation, falls, or delirium.

CONCLUSION

A multimodal, opioid-free perioperative pain management pathway is safe and effective in patients undergoing total shoulder arthroplasty and offers superior pain relief to that of a traditional opioid-containing pain management pathway at 12 hours, 24 hours, and 2 weeks postoperatively.

The analgesic efficacy of pregabalin for shoulder arthroscopy: A meta-analysis of randomized controlled trials

INTRODUCTION

The efficacy of pregabalin for pain management of shoulder arthroscopy remains controversial. We conduct this meta-analysis to explore the influence of pregabalin versus placebo on the postoperative pain intensity of shoulder arthroscopy.

METHODS

We have searched PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases through November 2019 for randomized controlled trials assessing the effect of pregabalin versus placebo on pain control of shoulder arthroscopy. This meta-analysis was performed using the random-effect model.

RESULTS

Three randomized controlled trials were included in the meta-analysis. Overall, compared with control group for shoulder arthroscopy, pregabalin remarkably decreased pain scores at 0 to 1 hour (Std. MD = -0.57; 95% CI = -1.04 to -0.09; P = .02) and 12 hours (Std. MD = -0.37; 95% CI = -0.72 to -0.02; P = .04), as well as analgesic consumption (Std. MD = -1.84; 95% CI = -2.24 to -1.44; P < .00001), but showed no notable influence on pain scores at 24 hours (Std. MD = -0.54; 95% CI = -1.47 to 0.38; P = .25), nausea or vomiting (RR = 0.84; 95% CI = 0.53-1.33; P = .45), dizziness (RR = 1.14; 95% CI = 0.89-1.47; P = .30).

CONCLUSIONS

Pregabalin may benefit to pain control after shoulder arthroscopy.

Meta-analyses of gabapentinoids for pain management after knee arthroplasty: A caveat emptor? A narrative review

The use of gabapentinoids for perioperative pain management after total knee arthroplasty has been the subject of nine systematic reviews and meta-analyses. A critical analysis of the clinical aspects of the methodology of these publications shows major flaws which limit the interpretation for the recommended use of perioperative gabapentinoids in pain management for unilateral primary total knee arthroplasty. Consequently, readers and authors of systematic reviews and meta-analyses should critically assess the clinical aspects of the included studies.

Percutaneous periarticular analgesic injection at one day after simultaneous bilateral total knee arthroplasty: an open-label randomized control trial

Background

The postoperative pain after total knee arthroplasty (TKA) remains a critical issue. The aim of this study was to assess the clinical effectiveness of percutaneous periarticular injection at 1 day following simultaneous bilateral TKA.

Methods

A total of 88 knees in 44 patients who underwent simultaneous bilateral TKA were randomly assigned to receive a percutaneous periarticular injection at 1 day following surgery (n = 22 patients) or no injection (n = 22 patients). In the additional injection group, we injected a solution including methylprednisolone, ropivacaine, and epinephrine into the muscle belly of the vastus medialis at 1 day after surgery. In both groups, patients received an intraoperative periarticular multi-drug injection and postoperative intravenous and oral nonsteroidal anti-inflammatory drugs. The primary outcome measure was the postoperative pain at rest using a visual analog scale (VAS) and analyzed with Student’s t test.

Results

Compared to the no additional injection group, the additional periarticular injection group had significantly lower VAS score at 8:00 PM postoperative day 1, 6:00 AM postoperative day 2, 12:00 PM postoperative day 2, 6:00 AM postoperative day 5, 12:00 PM postoperative day 5, and 8:00 PM postoperative day 5 (p < 0.05). The rate of complication did not differ between groups (p > 0.05).

Conclusion

Additional percutaneous periarticular injection at 1 day following TKA adding to intraoperative periarticular injection provided better postoperative pain relief.

Trial registration

Registered at the University Hospital Medical Information Network (registration number: UMIN000029759).

Perioperative pain management for shoulder surgery: evolving techniques

Improving management of postoperative pain following shoulder surgery is vital for optimizing patient outcomes, length of stay, and decreasing addiction to narcotic medications. Multimodal analgesia (ie, controlling pain via multiple different analgesic methods with differing mechanisms) is an ever-evolving approach to enhancing pain control perioperatively after shoulder surgery. With a variety of options for the shoulder surgeon to turn to, this article succinctly reviews the pros and cons of each approach and proposes a potential pain management algorithm.

Opioid Stewardship in Orthopaedic Surgery: Principles and Practice

The abuse of prescription opioid pain medication has contributed to the U.S. opioid crisis. Opioid stewardship programs ensure that our patients receive the safest and most effective opioid regimens. Opioid stewardship programs involve a multidisciplinary team, including pharmacists, orthopaedic surgeons, nurses, pain management personnel, and anesthesiologists. All of these stakeholders work together to formulate the best evidence-based use of these medications.

Pregabalin as a Pain Therapeutic: Beyond Calcium Channels

Initially developed to generate new treatments for epilepsy, gabapentin, and pregabalin (“gabapentinoids”) were engineered to mimic the action of GABA and to modulate GABA metabolism. Rather than their intended pharmacological action on GABA neurotransmission, instead, they exhibit a high affinity for the α2δ-1 and α2δ-2 subunits of voltage-activated calcium channels, wherein binding of gabapentinoids inhibits cellular calcium influx and attenuates neurotransmission. Despite a lack of activity on GABA levels, gabapentin and pregabalin are effective at suppressing seizures and subsequently approved as a new class of antiepileptic therapy for partial-onset epilepsy. Through the same hypothesized molecular mechanism and by controlling neuronal hyperexcitability, gabapentinoids demonstrate clear efficacy in pain management, which has arguably been their most extensively prescribed application to date. In this review, we focus on pregabalin as a second-generation gabapentinoid widely employed in the treatment of a variety of pain conditions. We also discuss the wider functional roles of α2δ subunits and the contributions that pregabalin might play in affecting physiological and pathophysiological processes.

Pain management after total knee arthroplasty: A prospective randomized study

INTRODUCTION

Total knee arthroplasty (TKA) is a common procedure for improving mobility and quality of life in patients with osteoarthritis. Postoperative pain control management after TKA is still a concern as it relates to patients satisfaction and functional recovery.Many anesthetic regimens and techniques have been explored to decrease postoperative pain and enhance the fast recovery after TKA. The aim of this study was to evaluate the best anesthetic treatment in pain control after TKA.

METHODS

51 patients were included in a randomized prospective study and distributed in three groups. The first group (CG) in which no analgesic protocol was implemented (control group). The second group (LIA group) received an intraoperative local infiltration anesthesia (LIA) (60 ml mixture of two ropivacaine 75mg/10 mL + adrenaline 100μg/10 mL + physiological solution). The third group (FNB group) had only a femoral nerve block (FNB). Continuous outcomes including visual analogue scale (VAS) at 5,24,48 h and at 1 week, morphine consumption and range of motion (ROM) at 1,2,7 days.

RESULTS

There was significant difference between all groups (p < 0,001) in terms of the VAS score: at 5h after surgery (4.55,2.15,1.82); at 24h (4.15,2.65,3.36); at 48h (3.85,2.45,2.73); at 1 week (2.95,1.80, 1.64), respectively for groups CG, LIA, FNB.ROM was better in LIA and FNB groups than CG: at 1 die after surgery (44°,50°,54°); at 3 dies (69°,70°,71°); at 7 dies (91°,98°,98°), respectively for groups CG, LIA, FNB (p < 0,001).

DISCUSSION

LIA and FNB groups both showed a significant reduction at VAS score, better range of motion and less morphine consumption than CG (control group). LIA group has obtained a constant pain control in the postoperative days; FNB group had a good pain control in the hours after surgery, with a decrease in efficacy in the following days.

CONCLUSION

Further studies are still needed in order to define LIA as the reference pain management in TKA.

Opioid-free shoulder arthroplasty: a prospective study of a novel clinical care pathway

BACKGROUND

Opioid therapy has been a cornerstone of perioperative pain control for decades in the United States, despite our increased understanding of the morbidity and mortality linked to opioids. The purpose of this study is to explore the safety, efficacy, and feasibility of an entirely opioid-free perioperative pathway in patients undergoing elective shoulder arthroplasty.

METHODS

Thirty-five patients undergoing elective total shoulder arthroplasty with a mean age of 71 (range, 50-87) years elected into a comprehensive opioid-free, multimodal pain management protocol. Opioid use was completely eliminated for all points in the perioperative period including during regional and general anesthesia. Data were collected regarding patient-reported pain, opioid consumption in the perioperative period, postoperative delirium, nausea, constipation, and falls.

RESULTS

Pain level at the primary outcome point of 24 hours or discharge was rated at 2.5 on the numeric rating scale. Stable, low pain scores were demonstrated at all time points postoperatively. Low rates of nausea, falls, and constipation were reported. Only 1 patient required "rescue" opioid medications during the in-patient stay, and an additional patient was given a low-dose opioid prescription at the 2-week postoperative appointment.

CONCLUSIONS

An opioid-free, multimodal pain management pathway is a safe and effective option in properly selected patients undergoing shoulder arthroplasty with a very low risk of requiring rescue opioids. This study is the first such study to present a surgical protocol entirely free of opioids at all portions of the patient care pathway.

Risk factors for postoperative delirium in patients undergoing lower extremity joint arthroplasty: a retrospective population-based cohort study

BACKGROUND

With an ageing population, the demand for joint arthroplasties and the burden of postoperative delirium is likely to increase. Given the lack of large-scale data, we investigated associations between perioperative risk factors and postoperative delirium in arthroplasty surgery.

METHODS

This retrospective population-based cohort study, utilized national claims data from the all-payer Premier Healthcare database containing detailed billing information from >25% nationwide hospitalizations. Patients undergoing elective total hip/knee arthroplasty surgery (2006-2016) were included.The primary outcome was postoperative delirium, while potential risk factors included age, gender, race, insurance type, and modifiable exposures including anesthesia type, opioid prescription dose (low/medium/high), benzodiazepines, meperidine, non-benzodiazepine hypnotics, ketamine, corticosteroids, and gabapentinoids.

RESULTS

Among 1 694 795 patients' postoperative delirium was seen in 2.6% (14 785/564 226) of hip and 2.9% (32 384/1 130 569) of knee arthroplasties. Multivariable models revealed that the utilization of long acting (OR 2.10 CI 1.82 to 2.42), combined long/short acting benzodiazepines (OR 1.74 CI 1.56 to 1.94), and gabapentinoids (OR 1.26 CI 1.16 to 1.36) was associated with increased odds of postoperative delirium. Lower odds of postoperative delirium were seen for neuraxial versus general anesthesia (OR 0.81 CI 0.70 to 0.93) and with the utilization of non-steroidal anti-inflammatory drugs (OR 0.85 CI 0.79 to 0.91) as well as cyclooxygenase-2 inhibitors (OR 0.82 CI 0.77 to 0.89). Age-stratified analysis revealed lower odds with high versus low opioid dose (OR 0.86 CI 0.76 to 0.98) in patients >65 years. Findings were consistent between hip and knee arthroplasties.

CONCLUSIONS

In this large national cohort, we identified various modifiable risk factors (including anesthesia type and pharmaceutical agents) for postoperative delirium, demonstrating possible prevention pathways.

Regional and Multimodal Analgesia to Reduce Opioid Use After Total Joint Arthroplasty: A Narrative Review

BACKGROUND

Elective total joint arthroplasty may be a gateway to long-term opioid use.

QUESTIONS/PURPOSE

We sought to review the literature on multimodal and regional analgesia as a strategy to minimize perioperative opioid use and control pain in patients undergoing total hip arthroplasty (THA) or total knee arthroplasty (TKA).

METHODS

We conducted a narrative review to assess the state of the evidence informing opioid-sparing analgesics for THA and TKA. A PubMed search was conducted for English-language articles published before April 2018. We preferentially included well-designed randomized controlled trials, systematic reviews, and meta-analyses. Where the highest levels of evidence were not yet apparent, we evaluated retrospective and/or observational studies.

RESULTS

Multimodal analgesia emphasizing nonsteroidal anti-inflammatory agents and acetaminophen is associated with decreases in perioperative opioid use for THA and TKA. Regional analgesia, including peripheral nerve blocks and local infiltration analgesia, is also associated with decreased perioperative opioid use for THA and TKA. Emerging topics in post-arthroplasty analgesia include (1) the value of nonsteroidal anti-inflammatory drugs, (2) the use of peripheral nerve catheters and extended-release local anesthetics to prolong the duration of opioid-free analgesia, and (3) novel peripheral nerve blocks, exemplified by the IPACK (interspace between the popliteal artery and posterior capsule of the knee) block for TKA.

CONCLUSIONS

The use of multimodal analgesia with regional techniques may decrease perioperative opioid use for patients undergoing THA and TKA. These techniques should be part of a comprehensive perioperative plan to promote adequate analgesia while minimizing overall opioid exposure.

Analgesic potential of PF-06372865, an α2/α3/α5 subtype-selective GABAA partial agonist, in humans

BACKGROUND

This study investigated the analgesic effects of two doses (15 and 65 mg) of PF-06372865, a novel α2/α3/α5 gamma-aminobutyric acid A (GABA_A) subunit selective partial positive allosteric modulator (PAM), compared with placebo and pregabalin (300 mg) as a positive control.

METHODS

We performed a randomised placebo-controlled crossover study (NCT02238717) in 20 healthy subjects, using a battery of pain tasks (electrical, pressure, heat, cold and inflammatory pain, including a paradigm of conditioned pain modulation). Pharmacodynamic measurements were performed at baseline and up to 10 h after dose.

RESULTS

A dose of 15 mg PF-06372865 increased pain tolerance thresholds (PTTs) for pressure pain at a ratio of 1.11 (90% confidence interval [CI]: 1.02, 1.22) compared with placebo. A dose of 65 mg PF-06372865 led to an increase in PTT for the cold pressor at a ratio of 1.17 (90% CI: 1.03, 1.32), and pressure pain task: 1.11 (90% CI: 1.01, 1.21). Pregabalin showed an increase in PTT for pressure pain at a ratio of 1.15 (95% CI: 1.06, 1.26) and cold pressor task: 1.31 (90% CI: 1.16, 1.48).

CONCLUSION

We conclude that PF-06372865 has analgesic potential at doses that do not induce significant sedation or other intolerable adverse events limiting its clinical use. In addition, the present study established the potential role for this battery of pain tasks as a tool in the development of analgesics with a novel mechanism of action, for the treatment of various pain states including neuropathic pain and to establish proof-of-concept.

CLINICAL TRIALS REGISTRATION

NCT0223871.

Updates on Multimodal Analgesia for Orthopedic Surgery

Pain control after orthopedic surgery is challenging. A multimodal approach provides superior analgesia with fewer side effects compared with opioids alone. This approach is particularly useful in light of the current opioid epidemic in the United States. Several new nonopioid agents have emerged into the market in recent years. New agents included in this review are intravenous acetaminophen, intranasal ketorolac, and newer nonsteroidal anti-inflammatory drugs, and the established medications ketamine and gabapentinoids. This article evaluates the evidence supporting these drugs in a multimodal context, including a brief discussion of cost.

Designing the ideal perioperative pain management plan starts with multimodal analgesia

Multimodal analgesia is defined as the use of more than one pharmacological class of analgesic medication targeting different receptors along the pain pathway with the goal of improving analgesia while reducing individual class-related side effects. Evidence today supports the routine use of multimodal analgesia in the perioperative period to eliminate the over-reliance on opioids for pain control and to reduce opioid-related adverse events. A multimodal analgesic protocol should be surgery-specific, functioning more like a checklist than a recipe, with options to tailor to the individual patient. Elements of this protocol may include opioids, non-opioid systemic analgesics like acetaminophen, non-steroidal anti-inflammatory drugs, gabapentinoids, ketamine, and local anesthetics administered by infiltration, regional block, or the intravenous route. While implementation of multimodal analgesic protocols perioperatively is recommended as an intervention to decrease the prevalence of long-term opioid use following surgery, the concurrent crisis of drug shortages presents an additional challenge. Anesthesiologists and acute pain medicine specialists will need to advocate locally and nationally to ensure a steady supply of analgesic medications and in-class alternatives for their patients’ perioperative pain management.

Is perioperative pregabalin effective for reducing postoperative pain in major surgery?

INTRODUCTION

Pregabalin is a structural analog of γ-aminobutyric acid that may have a role in acute pain management. It has been used in the perioperative context, but there is controversy regarding its real clinical utility.

METHODS

To answer this question we used Epistemonikos, the largest database of systematic reviews in health, which is maintained by screening multiple information sources, including MEDLINE, EMBASE, Cochrane, among others. We extracted data from the systematic reviews, reanalyzed data of primary studies, conducted a meta-analysis and generated a summary of findings table using the GRADE approach.

RESULTS AND CONCLUSIONS

We identified 21 systematic reviews including 77 randomized trials. We concluded the use of perioperative pregabalin in major surgeries probably does not produce a clinically important decrease in acute postoperative pain. Although it could decrease nausea, postoperative vomiting and opioid requirements, it also produces an increase in sedation.

Perioperative Pain Management in Hip and Knee Arthroplasty

Total hip and knee arthroplasty is associated with significant perioperative pain, which can adversely affect recovery by increasing risk of complications, length of stay, and cost. Historically, opioids were the mainstay of perioperative pain control. However, opioids are associated with significant downsides. Preemptive use of a multimodal pain management approach has become the standard of care to manage pain after hip and knee arthroplasty. Multimodal pain management uses oral medicines, peripheral nerve blocks, intra-articular injections, and other tools to reduce the need for opioids. Use of a multimodal approach promises to decrease complications, improve outcomes, and increase patient satisfaction after hip and knee arthroplasty.

The efficacy of gabapentin in reducing pain intensity and postoperative nausea and vomiting following laparoscopic cholecystectomy: A meta-analysis

BACKGROUND

It is unknown whether gabapentin is effective in reducing acute pain following laparoscopic cholecystectomy. The purpose of the current meta-analysis was to evaluate the efficacy of gabapentin in reducing pain intensity and postoperative nausea and vomiting (PONV) after laparoscopic cholecystectomy.

METHODS

All randomized controlled trials (RCTs) evaluating the efficacy of gabapentin in reducing pain intensity and PONV after laparoscopic cholecystectomy were searched on the following databases: PubMed, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), the Google database, the Chinese Wanfang database, and the China National Knowledge Infrastructure (CNKI). The most recent literature search was conducted on March 21, 2017. Outcomes including visual analog scale (VAS) at 12 and 24 hours, total morphine consumption, and the occurrence of PONV. Continuous outcomes were expressed as the weighted mean difference (WMD) and 95% confidence interval (CI), and the one discontinuous outcome was expressed as risk ratio (RR) and 95% CI. Stata 12.0 software was used for meta-analysis.

RESULTS

A total of 9 studies involving 966 patients were identified. In total, there were 484 gabapentin subjects and 482 controls. Compared with the control group, gabapentin was associated with lower VAS at 12 hours (WMD = -10.18, 95% CI: -17.36 to -2.80, P = .007) and 24 hours (WMD = -6.33, 95% CI: -8.41 to -4.25, P = .000), which was equivalent on a 110-point VAS scale to 10.18 points at 12 hours and 6.33 points at 24 hours. Compared with the control group, gabapentin was associated with less total morphine consumption by approximately 110.83 mg (WMD = -110.83, 95% CI: -183.25 to -38.42, P = .003). In addition, the occurrence of nausea and vomiting in gabapentin was decreased (25.2% vs 47.6, RR = 0.53, 95% CI: 0.44-0.63, P = .000).

CONCLUSION

Gabapentin was efficacious in reducing postoperative pain, total morphine consumption, and morphine-related complications following laparoscopic cholecystectomy. In addition, there was a negative correlation between the gabapentin dosage and the occurrence of nausea and vomiting. The number of included studies is limited, and more studies are needed to verify the effects of gabapentin in laparoscopic cholecystectomy patients.

A meta-analysis of the preoperative use of gabapentinoids for the treatment of acute postoperative pain following spinal surgery

BACKGROUND

Gabapentinoid drugs, which include gabapentin and pregabalin, play an established role in the management of neuropathic pain. However, whether preoperative administration of gabapentinoids has a beneficial role in controlling acute pain after spinal surgery is unknown. We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) to determine the efficacy and safety of the preoperative use of gabapentinoids (gabapentin and pregabalin) for the treatment of acute postoperative pain following spinal surgery.

METHODS

In March 2017, a systematic computer-based search was conducted in PubMed, EMBASE, Web of Science, Cochrane Library, and Google databases. RCTs comparing gabapentinoids (gabapentin and pregabalin) with placebo in patients undergoing spine surgery were retrieved. The primary endpoint was the visual analogue scale (VAS) score with rest or mobilization at 6, 12, 24, and 48 hours and cumulative morphine consumption at 24 and 48 hours. The secondary outcomes were complications of nausea, vomiting, sedation, dizziness, headache, urine retention, pruritus, and visual disturbances. After tests for publication bias and heterogeneity among studies were performed, data were aggregated for random-effects models when necessary.

RESULTS

Sixteen clinical studies (gabapentin group n = 8 and pregabalin group n = 8) were ultimately included in the meta-analysis. Gabapentinoids were associated with reduced pain scores at 6, 12, 24, and 48 hours. Similarly, gabapentinoids were associated with a reduction in cumulative morphine consumption at 24 and 48 hours. Furthermore, gabapentinoids can significantly reduce the occurrence of nausea, vomiting, and pruritus. There were no significant differences in the occurrence of sedation, dizziness, headache, visual disturbances, somnolence, or urine retention.

CONCLUSIONS

Preoperative use of gabapentinoids was able to reduce postoperative pain, total morphine consumption, and morphine-related complications following spine surgery. Further studies should determine the optimal dose and whether pregabalin is superior to gabapentin in controlling acute pain after spine surgery.

Intrathecal morphine versus femoral nerve block for pain control after total knee arthroplasty: a meta-analysis

Background

This meta-analysis aims to illustrate the efficacy and safety of intrathecal morphine (ITM) versus femoral nerve block (FNB) for pain control after total knee arthroplasty (TKA).

Methods

In April 2017, a systematic computer-based search was conducted in PubMed, EMBASE, Web of Science, Cochrane Database of Systematic Reviews, Cami Info. Inc., Casalini databases, EBSCO databases, Verlag database and Google database. Data on patients prepared for TKA surgery in studies that compared ITM versus FNB for pain control after TKA were collected. The main outcomes were the visual analogue scale (VAS) at 6, 12, 24, 48 and 72 and total morphine consumption at 12, 24 and 48 h. The secondary outcomes were complications that included postoperative nausea and vomiting (PONV) and itching. Stata 12.0 was used for pooling the data.

Results

Five clinical studies with a total of 225 patients (ITM group = 114, FNB group = 111) were ultimately included in the meta-analysis. The results revealed that the ITM group was associated with a reduction of VAS at 6, 12, 24, 48 and 72 h and total morphine consumption at 12, 24 and 48 h. There was no significant difference between the occurrences of PONV. However, the ITM group was associated with an increased occurrence of itching after TKA.

Conclusions

Some immediate analgesic efficacy and opioid-sparing effects were obtained with the administration of ITM when compared with FNB. The complications of itching in the ITM group were greater than in the FNB group. The sample size and the quality of the included studies were limited. A multi-centre RCT is needed to identify the optimal method for reaching maximum pain control after TKA.

Electronic supplementary material

The online version of this article (doi:10.1186/s13018-017-0621-0) contains supplementary material, which is available to authorized users.

Pregabalin can decrease acute pain and postoperative nausea and vomiting in hysterectomy: A meta-analysis

BACKGROUND

Whether the preoperative administration of pregabalin plays a beneficial role in controlling acute pain after hysterectomy is unknown. We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) to determine the efficacy and safety of the preoperative use of pregabalin to treat acute postoperative pain following hysterectomy.

METHODS

In April 2017, a systematic computer-based search was conducted in the PubMed, EMBASE, Web of Science, Cochrane Library, and Google databases. RCTs comparing pregabalin with placebo in patients undergoing hysterectomy were retrieved. The primary endpoint was the visual analog scale (VAS) score with rest or mobilization at 2 h, 4 and 24 hours and cumulative morphine consumption at 2, 4, 24, and 48 hours. The secondary outcomes were complications of nausea, vomiting, sedation, and dizziness. After tests for publication bias and heterogeneity among studies were performed, the data were aggregated for random-effects models when necessary.

RESULTS

Ten clinical studies with 1207 patients (pregabalin = 760, control = 447) were finally included in this meta-analysis. Preoperative administration of pregabalin was associated with a significant reduction of VAS with rest or mobilization at 2, 4, and 24 hours after hysterectomy. Further, the preoperative administration of pregabalin was associated with a reduction in total morphine consumption at 2, 4, 24, and 48 hours after hysterectomy. The occurrence of morphine-related complications (nausea and vomiting) was also reduced in the pregabalin group. However, the preoperative administration of pregabalin was associated with an increase in the occurrence of dizziness. There was no significant difference in the occurrence of sedation.

CONCLUSIONS

The preoperative use of pregabalin reduced postoperative pain, total morphine consumption, and morphine-related complications following hysterectomy. The doses of pregabalin were different, and large heterogeneity was the limitation of the current meta-analysis. Further studies should determine the optimal dose for controlling acute pain after hysterectomy.

Clinical, nociceptive and psychological profiling to predict acute pain after total knee arthroplasty

BACKGROUND

Pre-operative identification of high-pain responders for acute pain after total knee arthroplasty (TKA) could lead to targeted analgesic trials and individualized analgesic strategies to improve recovery and potentially reduce the risk of persistent post-surgical pain. The aim of this study was to use simple clinical tests and questionnaires to identify predictive nociceptive and psychological factors for acute post-TKA pain.

METHODS

Sixty consecutive TKA patients were included in a prospective descriptive study of pain during a 5-m walk-test 24 h post-operatively as the primary outcome. Predictive variables collected prior to surgery included demographics, nociceptive testing (pressure pain threshold (PPT), cold pressor tolerance, electrical pain threshold and tolerance) and psychological profile (pain catastrophizing scale (PCS) and hospital anxiety and depression scale). The prediction of acute post-TKA pain was assessed by univariate analysis, logistic regressions and ROC curves.

RESULTS

Reduced PPT on the arm and increased PCS were predictive variables for moderate/severe post-TKA pain 24 h after surgery (P = 0.007 and P = 0.026, respectively, R-squared 0.21) in the logistic regression model. Odds ratios were 0.67 for a 50 kPa increased PPT and 1.36 for a 5 point increase in PCS. A predictive model with cut-off values of PPT ≤ 245 kPa and PCS≥ 8 point had a sensitivity of 71.4 and a specificity of 62.5.

CONCLUSION

Pre-operative widespread pressure pain hypersensitivity and pain catastrophizing are predictive of moderate severe post-TKA pain. If validated in a larger population, the clinically applicable tests should be considered in future interventions aiming to minimize post-operative pain in high-risk patients.

Pregabalin can decrease acute pain and morphine consumption in laparoscopic cholecystectomy patients: A meta-analysis of randomized controlled trials

BACKGROUND

Pregabalin has been used as an adjunct for the management of acute pain in laparoscopic cholecystectomy. This meta-analysis aimed to illustrate the efficacy and safety of pregabalin for pain management following laparoscopic cholecystectomy.

METHODS

In March 2017, a systematic computer-based search was conducted in PubMed, EMBASE, Web of Science, Cochrane Database of Systematic Reviews, and Google databases. Data on patients prepared for laparoscopic cholecystectomy in studies that compared pregabalin versus placebo were retrieved. The primary endpoints were the visual analog scale (VAS) score with rest or mobilization at 6, 12, and 24 hours and total morphine consumption. The secondary outcomes were the morphine-related complications (i.e., nausea, vomiting, dizziness, somnolence, headache, pruritus, urine retention, respiratory depression, and blurred vision). Continuous outcomes were expressed as the weighted mean difference (WMD) with a corresponding 95% confidence interval (CI), and discontinuous outcomes were expressed as a risk ratio (RR) with a corresponding 95% CI.

RESULTS

Twelve clinical studies with 938 patients (gabapentin group = 536, control group = 402) were ultimately included in the meta-analysis. Pregabalin was associated with reduced pain scores with rest at 6, 12, and 24 hours, which corresponded to a reduction of 11.27 points at 6 hours, 9.46 points at 12 hours, and 3.99 points at 24 hours on a 100-point VAS. Moreover, pregabalin was associated with reduced pain scores with mobilization at 6, 12, and 24 hours, which corresponded to a reduction of 8.74 points, 5.80 points and 6.37 points at 6, 12, and 24 hours, respectively, on a 110-point VAS. Furthermore, pregabalin reduced the occurrence of nausea and vomiting. There were no significant differences in the occurrence of respiratory depression, pruritus, dizziness, blurred vision, and headache.

CONCLUSIONS

Pregabalin was efficacious in the reduction of postoperative pain, total morphine consumption, and morphine-related complications following laparoscopic cholecystectomy. In addition, a high dose of pregabalin was more effective than a low dose. The dose of pregabalin differed across the studies, and the heterogeneity was large. More studies are needed to verify the optimal dose of pregabalin in laparoscopic cholecystectomy patients.

Gabapentin can decrease acute pain and morphine consumption in spinal surgery patients: A meta-analysis of randomized controlled trials

BACKGROUND

Approximately 80% of patients who underwent spinal surgeries experience moderate to extreme postoperative pain. Gabapentin was used as an adjunct for the management of acute pain in approximately half of enhanced recovery programs. This meta-analysis aimed to illustrate the efficacy and safety of gabapentin for pain management following spinal surgery.

METHODS

In January 2017, a systematic computer-based search was conducted in PubMed, EMBASE, Web of Science, Cochrane Database of Systematic Reviews, and Google database. Data on patients prepared for spine surgery in studies that compared gabapentin versus placebo were retrieved. The primary endpoint was the visual analog scale (VAS) at 12 hours and 24 hours and total morphine consumption. The secondary outcomes were complications that included nausea, dizziness, somnolence, headache, pruritus, urine retention, and vomiting. After testing for publication bias and heterogeneity between studies, data were aggregated for random-effects models when necessary.

RESULTS

Seven clinical studies with 581 patients (gabapentin group=383, control group=198) were ultimately included in the meta-analysis. Gabapentin was associated with reduced pain scores at 12 hours and 24 hours, corresponding to a reduction of 11.18 points (95% CI, -13.85 to -8.52 points) at 12 hours and 9.94 points (95% CI, -13.99 to -5.89 points) at 24 hours on a 100-point VAS. Similarly, gabapentin was associated with a reduction in total morphine consumption (-2.04, 95% CI -2.71, -1.37). Furthermore, gabapentin can reduce the occurrence of vomiting (risk ratio [RR] 0.46, 95% CI 0.27, 0.78, P = 0.004), urine retention (RR = 0.57, 95% CI 0.34, 0.98, P = 0.041, NNT = 11.9) and pruritus (RR = 0.38, 95% CI 0.22, 0.66, P = 0.001, NNT = 5.6) and the number needed to treat (NNT = 20.1). There were no significant differences in the occurrence of nausea, dizziness, somnolence, or headache.

CONCLUSIONS

Gabapentin was efficacious in the reduction of postoperative pain, total morphine consumption, and morphine-related complications following spine surgery. In addition, a high dose (≥900 mg/d) of gabapentin is more effective than a low dose (<900 mg/d). The number of included studies is limited, and more studies are needed to verify the effects of gabapentin in spinal surgery patients.

Preoperative use of pregabalin for acute pain in spine surgery: A meta-analysis of randomized controlled trials

BACKGROUND

We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) to evaluate the efficacy and safety of pregabalin for pain management following spine surgery.

METHODS

In September 2016, a systematic computer-based search was conducted in PubMed, EMBASE, Web of Science, and Cochrane Database of Systematic Reviews. RCTs of patients prepared for spine surgery that compared pregabalin with placebo were retrieved. The primary endpoint was the VAS score with rest or mobilization at 12 hours, 24 hours, and 48 hours and cumulative morphine consumption at 24 hours and 48 hours. The secondary outcomes were complications of nausea, sedation, dizziness, headache, and visual disturbances. After testing for publication bias and heterogeneity between studies, data were aggregated for random-effects models when necessary.

RESULTS

Ten clinical studies with 535 patients (pregabalin group = 294, control group = 241) were included in the meta-analysis. Pregabalin was associated with reduced pain scores at 12 hours, 24 hours, and 48 hours, corresponding to a reduction of 1.91 points (95% CI, -4.07 to 0.24 point) at 12 hours, 2.66 points (95% CI, -4.51 to -0.81 point) at 24 hours, and 4.33 points (95% confidence interval, -6.38 to -2.99 point) at 48 hours on a 100-point numeric rating scale. There was no significant difference between VAS scores with mobilization at 12 hours, 24 hours, or 48 hours. Similarly, pregabalin was associated with a reduction in cumulative morphine consumption at 24 hours (-7.07, 95% CI -9.84, -4.30) and 48 hours (-6.52, 95% CI -7.78, -5.25, P = 0.000). Furthermore, pregabalin can reduce the occurrence of nausea (RR 0.57, 95% CI 0.41, 0.79, P = 0.001, number needed to treat = 8.4). There were no significant differences in the occurrence of sedation, dizziness, headache, or visual disturbances.

CONCLUSIONS

Preoperative use of pregabalin was efficacious in reduction of postoperative pain, total morphine consumption, and the occurrence of nausea following spine surgery. Because the sample size and the number of included studies were limited, a multicenter RCT is needed to identify the effects and optimal dose of pregabalin for reducing acute pain after spine surgery.

Local anesthetic infusion pump for pain management following total knee arthroplasty: a meta-analysis

Background

We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) were to evaluate the effect and safety of local anesthetic infusion pump versus placebo for pain management following total knee arthroplasty (TKA).

Methods

In September 2016, a systematic computer-based search was conducted in the Pubmed, ISI Web of Knowledge, Embase, Cochrane Database of Systematic Reviews. Randomized controlled trials of patients prepared for primary TKA that compared local anesthetic infusion pump versus placebo for pain management following TKA were retrieved. The primary endpoint was the visual analogue scale (VAS) with rest or mobilization at 24, 48 and 72 h and morphine consumption at 24 and 48 h. The second outcomes are range of motion, length of hospital stay (LOS) and complications (infection, deep venous thrombosis (DVT), prolonged drainage and postoperative nausea and vomiting (PONV)).

Results

Seven clinical studies with 587 patients were included and for meta-analysis. Local anesthetic infusion pump are associated with less pain scores with rest or mobilization at 24 and 48 h with significant difference. However, the difference was likely no clinical significance. There were no significant difference between the LOS, the occurrence of DVT, prolonged drainage and PONV. However, local anesthetic infusion pump may be associated with more infection.

Conclusion

Based on the current meta-analysis, we found no evidence to support the routine use of local anesthetic infusion pump in the management of acute pain following TKA. More RCTs are still need to identify the pain control effects and optimal dose and speed of local anesthetic pain pump.

Electroacupuncture Reduces the Effects of Acute Noxious Stimulation on the Electrical Activity of Pain-Related Neurons in the Hippocampus of Control and Neuropathic Pain Rats

To study the effects of acupuncture analgesia on the hippocampus, we observed the effects of electroacupuncture (EA) and mitogen-activated protein kinase (MEK) inhibitor on pain-excited neurons (PENs) and pain-inhibited neurons (PINs) in the hippocampal area CA1 of sham or chronic constrictive injury (CCI) rats. The animals were randomly divided into a control, a CCI, and a U0126 (MEK1/2 inhibitor) group. In all experiments, we briefly (10-second duration) stimulated the sciatic nerve electrically and recorded the firing rates of PENs and PINs. The results showed that in both sham and CCI rats brief sciatic nerve stimulation significantly increased the electrical activity of PENs and markedly decreased the electrical activity of PINs. These effects were significantly greater in CCI rats compared to sham rats. EA treatment reduced the effects of the noxious stimulus on PENs and PINs in both sham and CCI rats. The effects of EA treatment could be inhibited by U0126 in sham-operated rats. The results suggest that EA reduces effects of acute sciatic nerve stimulation on PENs and PINs in the CA1 region of the hippocampus of both sham and CCI rats and that the ERK (extracellular regulated kinase) signaling pathway is involved in the modulation of EA analgesia.