Development Of Chronic Postoperative Pain Research Articles

Association of a high rate of glycolysis and the activity of the uncoupling of oxidation and phosphorylation in the blood cells of patients with late-stage knee osteoarthritis and the development of postoperative pain

Objective: to investigate the relationship between the expression of genes mediating cellular energy production and the development of chronic postoperative pain (CPP) after total knee arthroplasty (TKA) in patients with osteoarthritis (OA).Material and methods. Prior to TKA, the blood of 50 patients with stage III–IV knee OA and complaints of constant pain and joint dysfunction was analyzed. The control group consisted of 26 healthy individuals. Pain intensity was assessed using a visual analogue scale (VAS), a short BPI questionnaire and the WOMAC index, and the presence of neuropathic pain was assessed using the DN4 and PainDETECT questionnaires. The development of CPP was determined 3 and 6 months after TKA. Total RNA isolated from blood was used to determine the expression of PKM2, LDH, SDH, AMPKα, PDH, IDH, MDH and ATP synthase genes by real-time quantitative reverse transcriptase-polymerase chain reaction.Results and discussion. CPP ≥30 mm according to VAS was detected in 17 patients. Before TKA, the expression of all analyzed genes was significantly increased compared to that of the control group. However, there were no differences in clinical, pain-related and functional indicators in the analyzed group of patients with OA. Before surgery, patients who subsequently developed CPP had significantly higher expression of genes related to glycolysis (PKM2, LDH), Krebs cycle – KC (SDH) and master regulator of energy metabolism (AMPKα) than patients who were satisfied with the results of TKA. At the same time, no differences were found in the expression of PDH and other KC enzyme genes (IDH, MDH) and ATP synthase in patients with and without CPP.Conclusion. The development of CPP is associated with a higher rate of glycolysis and energy deficiency, presumably due to the higher uncoupling activity of oxidation and phosphorylation that can be observed before TKA.

A longitudinal study of the prevalence of post-surgical inguinodynia and the factors responsible for the development of chronic pain among the patients undergoing open hernioplasty at a tertiary care center

Background: Chronic groin pain (Inguinodynia) is a potential complication following inguinal hernia mesh repair and has a significant impact on the quality of life. The incidence varies among studies ranging between 0% and 62.9%. Aims and Objectives: The present study was conducted with the objectives of estimating the prevalence of post-surgical inguinodynia among the patients undergoing open hernioplasty. The secondary objective was to assess the factors associated with the development of post-surgical inguinodynia. Materials and Methods: A longitudinal study was carried out in a tertiary care center in Bangalore, Karnataka among the hernia patients attending the outpatient department of General Surgery department. A pro forma prepared with expert validation was used to collect details regarding pre-operative characteristics, type of anesthesia, intraoperative findings, and post-operative complications. The pain was assessed by the visual analog scale. Descriptive statistics and Chi-square test were used to identify the risk factors. Results: A total of 112 patients underwent hernioplasty. Out of this, 108 were males and 4 were females. The mean age of the patients was 48±10.8 years. Majority of them (84, 77.7%) presented with indirect inguinal hernia. The prevalence of inguinodynia at 3-month post-hernia surgery was 21.4% (n=24). Patients with significant pre-operative pain had higher chances of developing chronic pain (P=0.000). It was found that post-operative surgical site infection was associated with increased chances of development of chronic pain (P=0.000). Conclusion: Our study found that around one-fifth of the hernia patients had developed chronic post-surgical inguinal pain following open hernioplasty. There was no significant relationship between patients’ characteristics and development of chronic post-operative pain. The presence of pre-operative pain and post-operative infection in the patients was significantly associated with the development of chronic pain. Intraoperative nerve identification and chronic post-operative pain did not have a significant relationship in our study. Most of the patients who developed chronic pain had experienced only mild pain and none of them had severe inguinal pain. From the findings of our study, we would like to recommend that all measures must be taken to prevent and treat post-operative surgical site infection which leads to the development of chronic pain in patients.

Inflammatory biomarkers in patients with painful knee osteoarthritis: exploring the potential link to chronic postoperative pain after total knee arthroplasty-a secondary analysis.

Total knee arthroplasty (TKA) is the end-stage treatment of knee osteoarthritis (OA), and approximately 20% of patients experience chronic postoperative pain. Studies indicate that inflammatory biomarkers might be associated with pain in OA and potentially linked to the development of chronic postoperative pain after TKA. This study aimed to (1) evaluate preoperative serum levels of inflammatory biomarkers in patients with OA and healthy control subjects, (2) investigate preoperative differences of inflammatory biomarker profiles in subgroups of patients, and (3) compare subgroups of patients with and without postoperative pain 12 months after surgery. Serum samples from patients with OA scheduled for TKA (n = 127) and healthy participants (n = 39) were analyzed. Patients completed the Knee-injury-and-Osteoarthritis-Outcome-Score (KOOS) questionnaire and rated their clinical pain intensity using a visual analog scale (VAS) before and 12 months after TKA. Hierarchical cluster analysis and Orthogonal Partial Least Squares Discriminant Analysis were used to compare groups (patients vs control subjects) and to identify subgroups of patients in relation to postoperative outcomes. Difference in preoperative and postoperative VAS and KOOS scores were compared across subgroups. Twelve inflammatory markers were differentially expressed in patients when compared with control subjects. Cluster analysis identified 2 subgroups of patients with 23 proteins being significantly different ( P < 0.01). The 12-months postoperative VAS and KOOS scores were significantly different between subgroups of patients ( P < 0.05). This study identified differences in specific inflammatory biomarker profiles when comparing patients with OA and control subjects. Cluster analysis identified 2 subgroups of patients with OA, with one subgroup demonstrating comparatively worse 12-month postoperative pain intensity and function scores.

Multidimensional evaluation of the pain profile as prognostic factor in individuals with hip or knee osteoarthritis receiving total joint replacement: protocol of a 2-year longitudinal prognostic cohort study

IntroductionKnee and hip osteoarthritis are two highly prevalent musculoskeletal pain conditions. Unsuccessful rates after hip/knee replacement range from 10% to 20%. Subjects with sensitisation manifestations are vulnerable to worse clinical...

PREVALENCE AND INTENSITY OF ACUTE POST-OPERATIVE PAIN AND MANAGEMENT ASPECTS IN ADULT PATIENTS: A CROSS-SECTIONAL TERTIARY HOSPITAL-BASED STUDY

The prevalence of acute postoperative pain varies widely, but quite often inadequate relief of acute postoperative pain is found, which, in turn, is associated with the development of chronic postoperative pain and other health consequences. The aim of the study was to determine the prevalence of acute postoperative pain and the degree of satisfaction of patients with anesthesia after surgery in four specialized hospitals in the capital of the country. The results showed that the post-operative pain prevalence is high 88.5% (95.0% CI = 81.2-95.8). Mean pain relief - 76.3, SD -14.8, median - 80%. Patients’ satisfaction with pain relief measured by NRS at the scores 9 and 10 composed 36.5% and 25.0% accordingly. Adequate perioperative pain management should be integral to patient care with active engagement of patients in pain management and taking decision in pain therapy.

Rationale for the use of TAP block technique for perioperative analgesia in laparoscopic cholecystectomy

Annotation. Acute postoperative pain is still a common unresolved health-care challenge even in highly developed countries. Insufficient postoperative pain control is associated not only with patients’ sufferings but also with increased incidence of complications (cardiovascular, thromboembolic, infectious, etc.), the development of chronic postoperative pain, delayed ambulation and discharge. Perioperative anesthesia is currently one of the main concerns in abdominal surgery. According to literature data, regional analgesia methods are widely used for anesthesia in perioperative period. Transversus abdominis plane (TAP) block proved to be a reliable regional technique of postoperative multimodal analgesia for anterior abdominal wall pain. Nowadays, ultrasound-guided TAP block techniques are considered to be a gold standard in many surgeries on anterolateral abdominal wall, producing consistent analgesia and having good safety profile. However, the quality of analgesia provided by TAP blocks under ultrasound guidance is different being influenced by the approach used. The choice between the variants of TAP block technique depends on the targeted region and the duration of nerve blockage. To date, the analgesic effect of anterior lateral abdominal wall blocks during laparoscopic cholecystectomy has not been sufficiently studied. The article provides the review of the latest advances in TAP block techniques as well as its standardized nomenclature, and suggests directions for future research. The aim was to analyze and substantiate the possibility of using regional anesthesia methods of the anterior abdominal wall by implementing the TAP-block type in the perioperative period during laparoscopic cholecystectomy. We have analyzed the current information and used the PubMed database. We have also analyzed the advantages of interstitial local anesthetic (TAP block), which primarily provides better control of pain in the anterior abdominal wall, and reduces the need for opiate and non-narcotic analgesics, the prescription of which may cause several side effects. There are many methods of the TAP-block, which to some extent depend on the pain localization in the anterior abdominal wall. For laparoscopic cholecystectomy, the most anatomically and theoretically justified is the oblique subcostal Tap-block. The use of regional techniques in laparoscopic cholecystectomy, namely the TAP-block, strategically fits into the concept of the accelerated recovery ERAS protocol, one of the purposes of which serves adequate control over the post-operative pain and early recovery.

Polymorphisms of the KCNS1, COMT and OPRM1 genes and development of postoperative pain in patients with osteoarthritis who underwent total knee or hip replacement

Postoperative pain (POP) is a serious complication that reduces the result of total knee (TKA) or hip arthroplasty (THA) in patients with osteoarthritis (OA). The search for predictors of postoperative pain is an actual problem.The aim of the study – to assessing relationship the polymorphisms of the KCNS1, COMT and OPRM1 genes and the development of POP in OA patients who underwent TKA or THA.Material and methods. The study group consisted of 95 patients with OA knee or hip (64.6% of women, 65.4±9.0 years) who underwent TKA (47.8%) or THA (52.2%). The presence of POP was determined when pain in the area of surgical intervention ≥40 mm (100 mm visual analog scale, VAS) persisted or appeared 3 and 6 months after surgery. All patients underwent genotyping of polymorphisms of the genes KCNS1 (rs734784), COMT (rs6269, rs4633) and OPRM1 (rs1799971) by polymerase chain reaction in real time using original sequence-specific primers and samples labeled with various fluorescent labels. Registration and interpretation of the obtained results were carried out on the DT-96 amplifier (DNA-Technology LLC, Russia).Results. POP was observed in 32.6% of patients who underwent TKA or THA. The frequency of POP after TKA and THA was 30.2% and 34.0% (p=0.882). Statistical analysis revealed no differences in the frequencies of the genotypes of the studied genes (p&gt;0,05). The presence of a homozygous genotype of the GG polymorphism of the KCNS1 gene (rs734784) was associated with the presence of POP in accordance with the recessive genetic model (GG vs AA+AG; odds ratio (OR) – 3.96 [95% confidence interval (CI): 1.51; 10.37]; p=0.005). The presence of the mutant allele T (TT+CT) in the genotype of the COMT polymorphism (rs4633) reduced the risk of POP compared to the carrier of the CC genotype (OR=0.32 [95% CI: 0.12; 0.83]; p=0.02) in accordance with the dominant genetic model. There was no significant correlation between the development of POP and the carrier of different genotypes and alleles of the COMT (rs6269) and OPRM1 (rs1799971) genes.Conclusions. There is a statistically significant association the polymorphism of the KCNS1 (rs734784) and COMT (rs4633) genes and the development of chronic POP in patients who underwent TKA or THA. Further studies of the genetic predisposition to POP are required on more clinical material.

Circulating long non-coding RNA signature in knee osteoarthritis patients with postoperative pain one-year after total knee replacement.

The incidence of chronic postoperative pain after total knee replacement (TKR) is approx. 20%, and hence preoperative risk factors are important to identify. Recent studies have indicated that preoperative inflammatory markers might hold prognostic information for the development of chronic postoperative pain. Long non-coding RNA (lncRNA) regulates the expression of genes related to e.g. inflammatory processes. The current study aimed to investigate the preoperative lncRNA signature as possible preoperative predictive markers for chronic postoperative pain following TKR. Serum samples, collected preoperatively from 20 knee osteoarthritis (KOA) patients, were analyzed for 84 validated circulatory lncRNA. Pain intensity was assessed using a visual analog scale (VAS) before and one-year after TKR. Differences for the lncRNA expression were analyzed between patients with chronic postoperative pain (VAS≥3) and those with a normal postoperative recovery (VAS<3). LncRNA Myeloid Zinc Finger 1 Antisense RNA 1 (MZF1-AS1) (fold change-3.99; p-value: 0.038) (shown to be involved neuropathic pain) Metastasis associated lung adenocarcinoma transcript 1 (MALAT1) (fold change-3.39; p-value: 0.044) (shown to be involved neuropathic pain); Patched 1 pseudogene (LOC100287846) (fold change-6.99; p-value: 0.029) (unknown in pain) were down-regulated preoperatively in the group with chronic postoperative pain compared to the group normal postoperative pain recovery. These findings suggest, that TKR patients with chronic postoperative pain present preoperative downregulations of three specific lncRNA detectable at thesystemic level. The presented study might give new insights into the complexity of chronic postoperative pain development and show how non-coding RNA plays a role in the underlying molecular mechanisms of pain.

A pilot multicentre randomised controlled trial of lidocaine infusion in women undergoing breast cancer surgery.

Chronic postoperative pain is common after breast cancer surgery. Peri-operative lidocaine infusion may prevent the development of chronic postoperative pain, but a large-scale trial is required to test this hypothesis. It is unclear whether a pragmatic, multicentre trial design that is consistent with expert guidance, addresses the limitations of previous studies, and overcomes existing translational barriers is safe, effective and feasible. We conducted a double-blind, randomised controlled pilot study in 150 patients undergoing breast cancer surgery across three hospitals in Western Australia. Patients received lidocaine, or equivalent volumes of saline, as an intravenous bolus (1.5mg.kg-1 ) and infusion (2mg.kg-1 .h-1 ) intra-operatively, and a subcutaneous infusion (1.33mg.kg-1 .h-1 ) postoperatively for up to 12h on a standard surgical ward, with novel safety monitoring tools in place. The co-primary outcomes were: in-hospital safety events; serum levels of lidocaine during intravenous and subcutaneous infusion; and annualised enrolment rates per site with long-term data capture. In-hospital safety events were rare, and similar in the placebo and lidocaine arms (3% vs. 1%). Median (IQR [range]) serum lidocaine levels during intravenous (2.16 (1.74-2.83 [1.12-6.06])µg.ml-1 , n=41) and subcutaneous (1.52 (1.28-1.83 [0.64-2.85])µg.ml-1 , n=48) infusion were comparable with previous trials reporting improved pain outcomes. Annualised enrolment approximated 50 patients per site per year, with high levels of protocol adherence and ≥99% capture of outcomes at 3 and 6months. The adjusted odds ratio (95%CI) for postoperative pain at 6months in the lidocaine arm was 0.790 (0.370-1.684). We conclude that this trial, as designed, is safe, effective and feasible in patients undergoing breast cancer surgery, and a larger-scale trial is planned.

Хронический болевой синдром, факторы риска развития на этапах хирургического вмешательства

At the present time, approximately 80% patients experience postoperative pain which is the leading entity in the overall structure of chronic pain. The aim of this article is investigation of reasons and risk factors underlying its development. Based on the information provided in domestic and international sources in open databases, analysis of these problems has been carried out. Selection of adequate therapy is particularly important against the background of the need for long-term intake of strong analgesics or the impossibility of pain management due to the neurogenic aetiology of the disease. In this connection, it is necessary to study factors predisposing patients to development of chronic postoperative pain and resort to prevention measures in order to reduce the risk of pain syndrome development.

Preoperative quantitative sensory testing and robot-assisted laparoscopic hysterectomy for endometrial cancer: Can chronic postoperative pain be predicted?

Objective: Chronic postoperative pain is prevalent after robot-assisted laparoscopic hysterectomy for endometrial cancer. Preoperative Quantitative Sensory Testing (QST) has been utilized to identify patients at risk of developing chronic postoperative pain after a variety of surgical procedures. The aim of this prospective, observational study was to determine whether preoperative QST profiling could predict the development of chronic postoperative pain following robot-assisted laparoscopic hysterectomy for endometrial cancer.

Preoperative quantitative sensory testing and robot-assisted laparoscopic hysterectomy for endometrial cancer: can chronic postoperative pain be predicted?

Objectives Chronic postoperative pain is prevalent after robot-assisted laparoscopic hysterectomy for endometrial cancer. Preoperative Quantitative Sensory Testing (QST) has been utilized to identify patients at risk of developing chronic postoperative pain after a range of surgical procedures. The aim of this prospective, observational study was to (1) determine the prevalence of chronic postoperative pain, (2) assess selected preoperative risk factors for chronic postoperative pain, and (3) evaluate if preoperative QST profiling could predict the development of chronic postoperative pain following robot-assisted laparoscopic hysterectomy for endometrial cancer. Methods One-hundred and sixty consecutive patients were included and handheld pressure algometry, cuff pressure algometry, temporal summation of pain, conditioned pain modulation, and heat pain thresholds were assessed prior to surgery. Patients were asked to fill out a questionnaire concerning pain in the pre- and post-operative time period six months after surgery. Chronic postoperative pain was defined as persistent, moderate to severe pain (mean visual analogue scale (VAS)≥3) on a daily basis six months after surgery. Results The prevalence of chronic postoperative pain after robot-assisted laparoscopic hysterectomy for endometrial cancer was of 13.6% (95% CI 8.4-20.4%). Patients that would develop chronic postoperative pain had a lower BMI (p=0.032), a higher prevalence of preoperative pelvic pain (p<0.001), preoperative heat pain hyperalgesia (p=0.043) and a higher level of acute postoperative pain (p<0.001) when compared to patients that would not develop chronic postoperative pain. A logistic regression model demonstrated that the presence of preoperative pelvic pain was a significant, independent predictive risk factor for development of chronic postoperative pain (OR=6.62, 95% CI 2.26-19.44), whereas none of the QST parameters could predict postoperative pain. Conclusions Preoperative QST assessment could not predict the development of chronic postoperative pain despite preoperative heat pain hyperalgesia in patients that would develop chronic postoperative pain.

The predictive value of quantitative sensory testing: a systematic review on chronic postoperative pain and the analgesic effect of pharmacological therapies in patients with chronic pain.

Studies have suggested that quantitative sensory testing (QST) might hold a predictive value for the development of chronic postoperative pain and the response to pharmacological interventions. This review systematically summarizes the current evidence on the predictive value of QST for chronic postoperative pain and the effect of pharmacological interventions. The main outcome measures were posttreatment pain intensity, pain relief, presence of moderate-to-severe postoperative pain, responders of 30% and 50% pain relief, or validated questionnaires on pain and disability. A systematic search of MEDLINE and EMBASE yielded 25 studies on surgical interventions and 11 on pharmacological interventions. Seventeen surgical and 11 pharmacological studies reported an association between preoperative or pretreatment QST and chronic postoperative pain or analgesic effect. The most commonly assessed QST modalities were pressure stimuli (17 studies), temporal summation of pain (TSP, 14 studies), and conditioned pain modulation (CPM, 16 studies). Of those, the dynamic QST parameters TSP (50%) and CPM (44%) were most frequently associated with chronic postoperative pain and analgesic effects. A large heterogeneity in methods for assessing TSP (n = 4) and CPM (n = 7) was found. Overall, most studies demonstrated low-to-moderate levels of risk of bias in study design, attrition, prognostic factors, outcome, and statistical analyses. This systematic review demonstrates that TSP and CPM show the most consistent predictive values for chronic postoperative pain and analgesic effect, but the heterogeneous methodologies reduce the generalizability and hence call for methodological guidelines.

Investigating the Effect of Perioperative Chlorzoxazone on Acute Postoperative Pain After Total Hip and Knee Replacement Surgery.

Severe preoperative and acute postoperative pain have been associated with the development of chronic postoperative pain. Chlorzoxazone (a muscle relaxant) has been suggested to enhance acute postoperative pain recovery, but the lack of larger randomized controlled trials has, however, questioned the continued use. Despite this, chlorzoxazone is still used for acute postoperative pain management following total knee replacement (TKR) or total hip replacement (THR). The current randomized, double-blinded, placebo-controlled, parallel-group, clinical trial aimed to assess the effect of chlorzoxazone for postoperative pain management following TKR or THR. A total of 393 patients scheduled for TKR or THR were included in the trial. Patients were assigned to 250 mg chlorzoxazone 3 times daily for the first 7 days postoperatively or to placebo. The primary outcome was pain after 5 m walk assessed 24 hours postoperatively. Secondary outcomes included changes in preoperative pain at rest, worst pain in the last 24 hours, and Oxford Knee or Hip Score compared with 12 months' follow-up. In addition, adverse events were assessed in the perioperative period. No significant differences were found for any of the outcome parameters after TKR or THR. As regards TKR or THR, no effects were demonstrated for pain after 5 m walk 24 hours after surgery (P>0.313), or for any of the secondary outcomes (P>0.288) or adverse events (P>0.112) in the group receiving chlorzoxazone compared with placebo. The current study demonstrated no analgesic effects of postoperative chlorzoxazone administration compared with placebo on acute or chronic postoperative pain 12 months following TKR and THR.

Influence of Mesh Fixation on the Development of Postoperative Pain after Laparoscopic Inguinal Hernia Repair: A Single Surgeon Experience.

Primary aim of the present article was to determine the relationship between mesh fixation methods and the occurrence of postoperative pain after laparoscopic inguinal hernia repair. Materials and Methods: 101 patients diagnosed with inguinal hernia benefited from elective laparoscopic treatment of the abdominal wall defect. Follow up was realized at one and three months after surgical intervention. The followed details contained clinical, surgical and pain-related data. Results: Multivariable analysis resulted young adults (OR=4.226; p=0.0467), recurrent hernia (OR=4.862; p=0.0415) and use of fixation requiring surgical mesh (OR=4.226; p=0.0467) as significant risk factors in the development of chronic postoperative pain. During the follow up period, patients who benefitted of mesh fixation complained about significantly higher pain sensation (pain index at one month: SG=10.27; CG=5.07; p=0.0080; pain index at three months: SG=5.02; CG=1.42; p=0.0406). Concerning chronic postoperative pain syndrome, six patients from SG (12.76%) and only a single patient from CG complained after three months about pain index greater than 18.5 points, concluding that mesh fixation significantly increases the possibility of chronic postoperative pain syndrome (p=0.0455). Conclusions: Mesh fixation methods during laparoscopic inguinal hernia repair seem to contribute to the development of chronic postoperative pain. Avoiding traumatizing mesh fixation methods could be a suitable option for surgeons.

The association between genome-wide polymorphisms and chronic postoperative pain: a prospective observational study.

SummaryChronic postoperative pain is common and can have a negative impact on quality of life. Recent studies show that genetic risk factors are likely to play a role, although only gene‐targeted analysis has been used to date. This is the first genome‐wide association study to identify single‐nucleotide polymorphisms associated with the development of chronic postoperative pain based on two independent cohorts. In a discovery cohort, 330 women scheduled for hysterectomy were genotyped. A case–control association analysis compared patients without chronic postoperative pain and the 34 who had severe chronic postoperative pain 3 months after surgery. No single‐nucleotide polymorphisms reached genome‐wide significance, but several showed suggestive associations with chronic postoperative pain (p < 1 × 10−5). Single‐nucleotide polymorphisms with significance p < 1 × 10−5 were followed up in a replication cohort consisting of 203 men and women scheduled for orthopaedic or abdominal surgery. Ten of these patients developed severe chronic postoperative pain. A single‐nucleotide polymorphism in NAV3 was significantly replicated with chronic postoperative pain in the replication cohort (p = 0.009). Meta‐analysis revealed that two loci (IQGAP1 and CRTC3) were significantly associated with chronic postoperative pain at 3 months (IQGAP1 p = 3.93 × 10−6 β = 2.3863, CRTC3 p = 2.26 × 10−6, β = 2.4209). The present genome‐wide association study provides initial evidence for genetic risk factors of chronic postoperative pain and supports follow‐up studies.

Preoperative serum circulating microRNAs as potential biomarkers for chronic postoperative pain after total knee replacement.

BackgroundChronic postoperative pain affects approximately 20% of patients with knee osteoarthritis after total knee replacement. Circulating microRNAs can be found in serum and might act as biomarkers in a variety of diseases. The current study aimed to investigate the preoperative expression of circulating microRNAs as potential predictive biomarkers for the development of chronic postoperative pain in the year following total knee replacement.MethodsSerum samples, collected preoperatively from 136 knee osteoarthritis patients, were analyzed for 21 circulatory microRNAs. Pain intensity was assessed using a visual analog scale before and one year after total knee replacement. Patients were divided into a low-pain relief group (pain relief percentage <30%) and a high-pain relief group (pain relief percentage >30%) based on their pain relief one year after total knee replacement, and differences in microRNAs expression were analyzed between the two groups.ResultsWe found that three microRNAs were preoperatively dysregulated in serum in the low-pain relief group compared with the high-pain relief group. MicroRNAs hsa-miR-146a-5p, -145-5p, and -130 b-3p exhibited fold changes of 1.50, 1.55, and 1.61, respectively, between the groups (all P values < 0.05). Hsa-miR-146a-5p and preoperative pain intensity correlated positively with postoperative pain relief (respectively, R = 0.300, P = 0.006; R = 0.500, P < 0.001).DiscussionThis study showed that patients with a low postoperative pain relief present a dysregulation of circulating microRNAs. Altered circulatory microRNAs expression correlated with postoperative pain relief, indicating that microRNAs can serve as predictive biomarkers of pain outcome after surgery and hence may foster new strategies for preventing chronic postoperative pain after total knee replacement (TKR).

Chronic Postoperative Pain After Hysterectomy for Endometrial Cancer: A Metabolic Profiling Study.

IntroductionOne out of seven women will develop a state of chronic postoperative pain following robot-assisted hysterectomy for endometrial cancer. Recently, metabolic studies have indicated that circulating lipids and lipoproteins could act as nociceptive modulators and thereby influence the induction and perpetuation of pain. The objectives of this explorative study were (1) to examine the preoperative serologic variations in concentrations of lipids, lipoproteins, and various low‐molecular metabolites in patients with and without chronic postoperative pain after robot-assisted hysterectomy and (2) to explore if any of these serological biomarkers were predictive for development of chronic postoperative pain.Materials and MethodsThe study was designed as a nested case–control study within a cohort of women treated for endometrial cancer with robot-assisted laparoscopic hysterectomy. Twenty-six women with chronic postoperative pain were matched on age and body mass index with fifty-two controls without chronic postoperative pain, and metabolic profiling of preoperatively drawn blood samples from a biobank was performed by means of nuclear magnetic resonance spectroscopy.ResultsNineteen metabolites, including cholesterol, cholesteryl ester, linoleic acid, phospholipids, lipids, and triglycerides had statistically significant higher concentrations in a subgroup of patients who would develop chronic postoperative pain on a later stage compared to the group of patients who would not develop chronic postoperative pain (p < 0.05). A sparse Partial Least Squares-Discriminant Analysis model explained 38.1% of the variance and had a predictive accuracy of 73.1%.ConclusionsThis explorative study substantiates the hypothesis that certain lipids, lipoproteins, and fatty acids are associated with chronic postoperative pain.

Remifentanil for abdominal surgery is associated with unexpectedly unfavorable outcomes.

Insufficient perioperative pain treatment is known as a highly predictive risk factor for the development of chronic postoperative pain. Remifentanil is an ultrashort-acting opioid that provides quick and efficient analgesia but is associated with the induction of opioid-induced hyperalgesia. Despite these well-known characteristics, this substance is being increasingly used in anesthesia and in a variety of medical fields, such as intensive-care medicine and obstetrics. The aim of our study was to reveal whether remifentanil influences postoperative pain, the requirement for postoperative analgesics, and requirement of antiemetics (as indirect indicator of postoperative nausea and vomiting), as well as the effects on time to extubation and length of stay in the postanesthesia care unit in daily clinical routine. From an electronic medical records database of 55,693 anesthesias, we analyzed data from all patients receiving intraabdominal surgery (visceral, gynecological, and urological) under general anesthesia or combined general-epidural anesthesia by propensity score matching. The administration of remifentanil was associated with higher postoperative pain scores despite a higher requirement of postoperative analgesics. Additional epidural analgesia was not able to avoid this finding. The intraoperative use of remifentanil is associated with a deterioration of pain levels and postoperative analgesic requirement, wherefore the potential benefit of this substance seems to be outweighed by its potential disadvantages. Especially in operative procedures in which high postoperative pain scores are expected, the unreflective use should be critically questioned.

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).