Bridging the pain gap after cancer surgery - Evaluating the feasibility of transitional pain service to prevent persistent postsurgical pain - A systematic review and meta-analysis.

Background and Aims: The lack of a dedicated pain service catering to the postsurgical period has resulted in the origination of the pain-period gap. This has led to a resurgence of transitional pain service (TPS). Our objective was to evaluate the feasibility of TPS in pain practice among postsurgical cancer patients and its prevention of persistent postsurgical pain (PPSP), culminating in chronic pain catastrophising. Methods: The protocol for this meta-analysis was registered in the International Prospective Register of Systematic Reviews (ID: CRD42023407190). This systematic review included articles involving all adult cancer patients undergoing cancer-related surgery experiencing pain, involving pharmacological, non-pharmacological and interventional pain modalities after an initial systematic pain assessment by pain care providers across diverse clinical specialities, targeting multimodal integrative pain management. Meta-analysis with meta-regression was conducted to analyse the feasibility of TPS with individual subgroup analysis and its relation to pain-related patient outcomes. Results: Three hundred seventy-four articles were evaluated, of which 14 manuscripts were included in the meta-analysis. The lack of randomised controlled trials evaluating the efficacy of TPS in preventing PPSP and pain catastrophising led to the analysis of its feasibility by meta-regression. The estimate among study variances τ2 was determined and carried out along with multivariate subgroup analysis. A regression coefficient was attained to establish the correlation between the feasibility of TPS and its patient outcome measures and opioid-sparing. Conclusion: TPS interventions carried out by multidisciplinary teams incorporating bio-physical-psychological pain interventions have resulted in its successful implementation with improved pain-related patient outcomes mitigating the occurrence of PPSP.

Perioperative Risk Factors for Persistent Postsurgical Pain After Inguinal Hernia Repair: Systematic Review and Meta-Analysis.

Persistent postsurgical pain (PPSP) is one of the most bothersome and disabling long-term complications after inguinal hernia repair surgery. Understanding perioperative risk factors that contribute to PPSP can help identify high-risk patients and develop risk-mitigation approaches. The objective of this study was to systematically review and meta-analyze risk factors that contribute to PPSP after inguinal hernia repair. The literature search resulted in 303 papers included in this review, 140 of which were used for meta-analyses. Our results suggest that younger age, female sex, preoperative pain, recurrent hernia, postoperative complications, and postoperative pain are associated with a higher risk of PPSP. Laparoscopic techniques reduce the PPSP occurrence compared to anterior techniques such as Lichtenstein repair, and tissue-suture techniques such as Shouldice repair. The use of fibrin glue for mesh fixation was consistently associated with lower PPSP rates compared to tacks, staples, and sutures. Considerable variability was observed with PPSP assessment and reporting methodology in terms of study design, follow-up timing, clarity of pain definition, as well as pain intensity or interference threshold. High or moderate risk of bias in at least one domain was noted in >75% of studies. These may limit the generalizability of our results. Future studies should assess and report comprehensive preoperative and perioperative risk factors for PPSP adjusted for confounding factors, and develop risk-prediction models to drive stratified PPSP-mitigation trials and personalized clinical decision-making. PERSPECTIVE: This systematic review and meta-analysis summarizes the current evidence on risk factors for persistent pain after inguinal hernia repair. The findings can help identify patients at risk and test personalized risk-mitigation approaches to prevent pain. PROSPERO REGISTRATION: htttps://www.crd.york.ac.uk/prospero/display_record.php?RecordID=154663.

The analgesic effectiveness of perioperative lidocaine infusions for acute and chronic persistent postsurgical pain in patients undergoing breast cancer surgery: a systematic review and meta-analysis.

BACKGROUND: Breast cancer is the most common cancer among women and tumour resection carries a high prevalence of chronic persistent postsurgical pain (CPSP). Perioperative i.v. lidocaine infusion has been proposed as protective against CPSP; however, evidence of its benefits is conflicting. This review evaluates the effectiveness of perioperative lidocaine infusions for breast cancer surgery. METHODS: Randomised trials comparing perioperative lidocaine infusions with parenteral analgesia in breast cancer surgery patients were sought. The two co-primary outcomes were the odds of CPSP at 3 and 6 months after operation. Secondary outcomes included rest pain at 1, 6, 12, and 24 h; analgesic consumption at 0-24 and 25-48 h; quality of recovery; opioid-related side-effects; and lidocaine infusion side-effects. Hartung-Knapp-Sidik-Jonkman (HKSJ) random effects modelling was used. RESULTS: Thirteen trials (1039 patients; lidocaine: 518, control: 521) were included. Compared with control, perioperative lidocaine infusion did not decrease the odds of developing CPSP at 3 and 6 months. Lidocaine infusion improved postoperative pain at 1 h by a mean difference (95% confidence interval) of -0.65 cm (-0.73 to -0.57 cm) (P<0.0001); however, this difference was not clinically important (1.1 cm threshold). Similarly, lidocaine infusion reduced oral morphine consumption by 7.06 mg (-13.19 to -0.93) (P=0.029) over the first 24 h only; however, this difference was not clinically important (30 mg threshold). The groups were not different for any of the remaining outcomes. CONCLUSIONS: Our results provide moderate-quality evidence that perioperative lidocaine infusion does not reduce CPSP in patients undergoing breast cancer surgery. Routine use of lidocaine infusions for perioperative analgesia and CPSP prevention is not supported in this population. SYSTEMATIC REVIEW PROTOCOL: PROSPERO CRD42023420888.

Evaluating the Predictive Value of a Short Preoperative Holistic Risk Factor Screening Questionnaire in Preventing Persistent Pain in Elective Adult Surgery: Study Protocol for a Prospective Observational Pragmatic Trial [PERISCOPE].

Background: The global incidence of persistent pain after surgery is approximately 10%, with considerable clinical and socioeconomic impacts. Despite identifying many risk factors in its development and the challenging management of the often neuropathic pain complaints, preoperative recognition of high-risk patients in various surgical populations using a standardized risk factor assessment questionnaire is lacking. This study evaluates the predictive value of a short holistic risk factor screening questionnaire as a first step in preventing and treating persistent pain in adults undergoing elective surgery. Methods: This prospective observational pragmatic trial will include 560 adults undergoing elective surgery. The primary endpoint is the evaluation of the predictive value of the screening questionnaire, including the optimal cut-off determination in terms of sensitivity and specificity for inclusion in a perioperative high-vigilance program. Secondary endpoints are postoperative pain (intensity and characterization using the NRS and DN4), postoperative analgesic usage, and well-being using the EQ-5D-5 L. To assess the performance of the designed screening questionnaire in the identification of psychosocial pain aspects, HADs, and STAI-trait are being surveyed. Additionally, the multidimensional pain inventory (MPI, part 1) is being used to assess the impact of pain on daily life in patients. Discussion: This pragmatic clinical trial will evaluate a short preoperative screening questionnaire to predict persistent postoperative pain after elective surgery in adults. Suppose high-risk patients could be identified earlier using this short preoperative holistic screening questionnaire. In that case, it might contribute to a more widespread implementation of standardized preoperative assessment and awareness for preventing persistent postoperative pain. Trial Registration: Local ethics committee: B3002022000112. ClinicalTrials.gov identifier: NCT05526976. Registered on: 02 September 2022. Start of recruitment: 22 December 2022. Trial Status: This paper is based on protocol version 4.0. The first patient was assigned to the research project on the 22 of December 2022. We anticipate including the last patient in October 2023 and plan to finalize the study by January 2024.

Healthcare delivery gaps in pain management within the first 3 months after discharge from inpatient noncardiac surgeries: a scoping review.

BACKGROUND: Poor pain control during the postoperative period has negative implications for recovery, and is a critical risk factor for development of persistent postsurgical pain. The aim of this scoping review is to identify gaps in healthcare delivery that patients undergoing inpatient noncardiac surgeries experience in pain management while recovering at home. METHODS: Searches were conducted by a medical librarian in PubMed, MEDLINE, EMBASE, EBSCO CINAHL, Web of Science, and Cochrane Database of Systematic Reviews for articles published between 2016 and 2022. Inclusion criteria were adults (≥18 yr), English language, inpatient noncardiac surgery, and included at least one gap in care for acute and/or persistent pain management after surgery within the first 3 months of recovery at home. Two reviewers independently screened articles for inclusion and extracted data. Quotations from each article related to gaps in care were synthesised using thematic analysis. RESULTS: There were 4794 results from databases and grey literature, of which 38 articles met inclusion criteria. From these, 23 gaps were extracted, encompassing all six domains of healthcare delivery (capacity, organisational structure, finances, patients, care processes and infrastructure, and culture). Identified gaps were synthesised into five overarching themes: education (22 studies), provision of continuity of care (21 studies), individualised management (10 studies), support for specific populations (11 studies), and research and knowledge translation (10 studies). CONCLUSIONS: This scoping review identified health delivery gaps during a critical period in postoperative pain management. These gaps represent potential targets for quality improvement and future research to improve perioperative care and longer-term patient-centred outcomes. SCOPING REVIEW PROTOCOL: Open Science Framework (https://osf.io/cq5m6/).

Chronic post-thoracotomy pain after lung cancer surgery: a prospective study of preoperative risk factors.

OBJECTIVES: The objective of this longitudinal cohort study was to investigate if preoperative pain mechanisms, anxiety, and depression increase risk of developing chronic post-thoracotomy pain (CPTP) after lung cancer surgery. METHODS: Patients with suspected or confirmed lung cancer undergoing surgery by either video-assisted thoracoscopic surgery or anterior thoracotomy were recruited consecutively. Preoperative assessments were conducted by: quantitative sensory testing (QST) (brush, pinprick, cuff pressure pain detection threshold, cuff pressure tolerance pain threshold, temporal summation and conditioned pain modulation), neuropathic pain symptom inventory (NPSI), and the Hospital Anxiety and Depression Scale (HADS). Clinical parameters in relation to surgery were also collected. Presence of CPTP was determined after six months and defined as pain of any intensity in relation to the operation area on a numeric rating scale form 0 (no pain) to 10 (worst pain imaginable). RESULTS: A total of 121 patients (60.2 %) completed follow-up and 56 patients (46.3 %) reported CPTP. Development of CPTP was associated with higher preoperative HADS score (p=0.025), higher preoperative NPSI score (p=0.009) and acute postoperative pain (p=0.042). No differences were observed in relation to preoperative QST assessment by cuff algometry and HADS anxiety and depression sub-scores. CONCLUSIONS: High preoperative HADS score preoperative pain, acute postoperative pain intensity, and preoperative neuropathic symptoms were was associated with CPTP after lung cancer surgery. No differences in values of preoperative QST assessments were found. Preoperative assessment and identification of patients at higher risk of postoperative pain will offer opportunity for further exploration and development of preventive measures and individualised pain management depending on patient risk profile.

"I am accustomed to something in my body causing pain": a qualitative study of knee replacement non-improvers' stories of previous painful and stressful experiences.

BACKGROUND: Approximately 20% of total knee arthroplasty patients experience persistent postsurgical pain one year after surgery. No qualitative studies have explored previous stories of painful or stressful life experiences in patients experiencing persistent postsurgical pain after total knee replacement. This study aimed to explore stories of previous painful or stressful experiences in life in a cohort of patients that reported no improvement in pain one year after total knee arthroplasty. METHODS: The study employed an explorative-descriptive qualitative design. Data was collected through semi-structured interviews five to seven years after surgery, with patients who reported no improvement in pain-related interference with walking 12 months after total knee replacement. The data was analyzed using qualitative content analysis. RESULTS: The sample consisted of 13 women and 10 men with a median age of 67 years at the time of surgery. Prior to surgery, six reported having at least one chronic illness and 16 reported having two or more painful sites. Two main themes were identified in the data analysis: Painful years - the burden of living with long lasting pain, and the burden of living with psychological distress. CONCLUSIONS: The participants had severe longlasting knee pain as well as longlasting pain in other locations, in addition to experiences of psychologically stressful life events before surgery. Health personnel needs to address the experience and perception of pain and psychological struggles, and how it influences patients' everyday life including sleeping routines, work- and family life as well as to identify possible vulnerability for persistent postsurgical pain. Identifying and assessing the challenges enables personalized care and support, such as advice on pain management, cognitive support, guided rehabilitation, and coping strategies both pre-and post-surgery.

Trajectory of worst pain within the first two weeks following pelvic and sacral tumor surgery and long-term outcome: a pilot observational prospective cohort study.

BACKGROUND: Pain management after pelvic and sacral tumor surgery is challenging and requires a multidisciplinary and multimodal approach. Few data on postoperative pain trajectories have been reported after pelvic and sacral tumor surgery. The aim of this pilot study was to determine pain trajectories within the first 2 weeks after surgery and explore the impact on long-term pain outcomes. METHODS: Patients scheduled for pelvic and sacral tumor surgery were prospectively recruited. Worst/average pain scores were evaluated postoperatively using questions adapted from the Revised American Pain Society Patient Outcome Questionnaire (APS-POQ-R) until pain resolution was reached or up to 6 months after surgery. Pain trajectories over the first 2 weeks were compared using the k-means clustering algorithm. Whether pain trajectories were associated with long-term pain resolution and opioid cessation was assessed using Cox regression analysis. RESULTS: A total of 59 patients were included. Two distinct groups of trajectories for worst and average pain scores over the first 2 weeks were generated. The median pain duration in the high vs low pain group was 120.0 (95% CI [25.0, 215.0]) days vs 60.0 (95% CI [38.6, 81.4]) days (log rank p = 0.037). The median time to opioid cessation in the high vs low pain group was 60.0 (95% CI [30.0, 90.0]) days vs 7.0 (95% CI [4.7, 9.3]) days (log rank p < 0.001). After adjusting for patient and surgical factors, the high pain group was independently associated with prolonged opioid cessation (hazard ratio [HR] 2.423, 95% CI [1.254, 4.681], p = 0.008) but not pain resolution (HR 1.557, 95% CI [0.748, 3.243], p = 0.237). CONCLUSIONS: Postoperative pain is a significant problem among patients undergoing pelvic and sacral tumor surgery. High pain trajectories during the first 2 weeks after surgery were associated with delayed opioid cessation. Research is needed to explore interventions targeting pain trajectories and long-term pain outcomes. TRIAL REGISTRATION: The trial was registered at ClinicalTrials.gov ( NCT03926858 , 25/04/2019).

Factors associated with persistent postsurgical pain after total knee or hip joint replacement: a systematic review and meta-analysis.

Studies have identified demographic, clinical, psychosocial, and perioperative variables associated with persistent pain after a variety of surgeries. This study aimed to perform a systematic review and meta-analysis of factors associated with persistent pain after total knee replacement (TKR) and total hip replacement (THR) surgeries. To meet the inclusion criteria, studies were required to assess variables before or at the time of surgery, include a persistent postsurgical pain (PPSP) outcome measure at least 2 months after a TKR or THR surgery, and include a statistical analysis of the effect of the risk factor(s) on the outcome measure. Outcomes from studies implementing univariate and multivariable statistical models were analyzed separately. Where possible, data from univariate analyses on the same factors were combined in a meta-analysis. Eighty-one studies involving 171,354 patients were included in the review. Because of the heterogeneity of assessment methods, only 44% of the studies allowed meaningful meta-analysis. In meta-analyses, state anxiety (but not trait anxiety) scores and higher depression scores on the Beck Depression Inventory were associated with an increased risk of PPSP after TKR. In the qualitative summary of multivariable analyses, higher preoperative pain scores were associated with PPSP after TKR or THR. This review systematically assessed factors associated with an increased risk of PPSP after TKR and THR and highlights current knowledge gaps that can be addressed by future research.

The waiting game: investigating the neurobiological transition from acute to persistent pain in adolescent rats.

Persistent postsurgical pain affects 20% of youth undergoing a surgical procedure, with females exhibiting increased prevalence of chronic pain compared with males. This study sought to examine the sexually-dimorphic neurobiological changes underlying the transition from acute to persistent pain following surgery in adolescence. Male and female Sprague Dawley rats were randomly allocated to a sham or injury (plantar-incision surgery) condition and assessed for pain sensitivity while also undergoing magnetic resonance imaging at both an acute and chronic timepoint within adolescence. We found that injury resulted in persistent pain in both sexes, with females displaying most significant sensitivity. Injury resulted in significant gray matter density increases in brain areas including the cerebellum, caudate putamen/insula, and amygdala and decreases in the hippocampus, hypothalamus, nucleus accumbens, and lateral septal nucleus. Gray matter density changes in the hippocampus and lateral septal nucleus were driven by male rats whereas changes in the amygdala and caudate putamen/insula were driven by female rats. Overall, our results indicate persistent behavioral and neurobiological changes following surgery in adolescence, with sexually-dimorphic and age-specific outcomes, highlighting the importance of studying both sexes and adolescents, rather than extrapolating from male adult literature.

Identifying molecular mechanisms of acute to chronic pain transition and potential drug targets.

INTRODUCTION: Chronic pain is pain that lasts more than the normal physiologic healing time at the time of initial insult. The transition from acute to chronic pain has been studied thoroughly. Understanding the mechanisms underlying chronic pain formation is essential for the development of novel treatments and therapeutics for chronic pain prevention. AREA COVERED: The transition from acute to chronic pain has been associated with the intracellular changes caused by repeated stimulus application, or neuronal priming, allowing for the chronicity of pain. Ongoing research studies have shown this priming to occur at various sites along the pathway for the neural transmission of pain. The purpose of this review is to not only elucidate the transition from acute to chronic pain and discuss current studies/trials related to this transition but also to highlight mechanisms involved in the process that could serve as potential targets for chronic pain prevention. EXPERT OPINION: We are providing an overview of novel treatment strategies for preventing the transition from acute to chronic pain. A multifaceted and multimodal approach that invokes multiple targets, at least one from each section (the periphery, the spinal cord, and the brain), would be the best option for tackling this problem.

Prevalence of Chronic Postsurgical Pain among Cancer Patients: A Cross-Sectional Study.

Background: Cancer patients accept surgeries as part of their treatment. They may not be aware of the possibility of surgical pain persisting long after the surgery. Understanding chronic postsurgical pain is essential for effective pain management. Aims: We aimed to assess the prevalence of chronic postsurgical pain in cancer patients and the associated symptom burden. Settings and Design: This study was carried out at a tertiary cancer center. It was a cross-sectional study. Materials and Methods: Participants who underwent surgeries were asked to provide feedback on the MD Anderson Symptom Inventory at 3 months. Statistical Analysis Used: Descriptive statistics were used. Statistical tests included Kruskal-Wallis test, Chi-square test, Fisher's exact test, and Spearman's correlation. Logistic regression was used to assess the influence of variables on the presence or absence of chronic postsurgical pain. Results: Nine hundred and eighteen participants completed the study. Ninety-two percent (n = 840) were asymptomatic. Eight percent (n = 78) had postsurgical pain. Chronic postsurgical pain was influenced by the type of surgery (P = 0.01), specifically orthopedic and thoracic surgeries. Patients who receive epidurals are three times less likely to continue to have pain at 3 months. Conclusions: The prevalence of chronic postsurgical pain at 3 months in this study is lower than the rates in the literature. It is still associated with symptom burden that interferes with daily life. The risk of developing chronic postsurgical pain increases with thoracic and orthopedic surgeries. The risk may be lowered with epidural analgesia.

Multimodal Analgesia.

Perioperative pain management is one of the domains in which Anesthesiologists are intricately involved, and which is immensely important. Adequate postoperative analgesia is central to avoid both the acute as well as chronic complications of uncontrolled postoperative pain. Preventive analgesia has been identified as an approach to mitigate the phenomenon of central sensitization, which plays an important role in the development of chronic pain after surgery. As an over-reliance on opioids for peri- and postoperative pain control is associated with opioid dependence and hyperalgesia, multimodal analgesia has taken center stage. Multimodal analgesia, in theory, will optimize perioperative pain control, reduce the chance of central sensitization, and avoid the detrimental effects of opioid overuse. Multiple classes of systemic analgesic medications have been used to accomplish these tasks, and the aim of this article is to outline these medications, their mechanisms of action, as well as the evidence behind their individual roles in multimodal analgesia. Regional anesthesia has also been embraced as a key component of multimodal analgesia in orthopedic surgery; however, over the past several years, local infiltration analgesia (LIA) emerged as a viable alternative, particularly in total knee arthroplasty.

[Effects of intrathecal injection of IRF8 SiRNA on pain threshold and activation of spinal cord microglia in rats with postoperative persistent pain].

Objective: To investigate the effects of intrathecal injection of IRF8 SiRNA on the pain threshold and activation of spinal cord microglia in rats with postoperative persistent pain. Methods: One hundred and twenty male Sprague-Dawley rats were randomly divided into sham group (SH, n=12), SMIR group (SM, n=48), SMIR + DEPC group (SD, n=12) and SMIR + irf8 SiRNA group (SS, n=48). In the SM group, the persistent postsurgical pain(PPsP) model was established according to the skin/muscle incision and retraction (SMIR), and the SH group was only incised without retracted. The SD group and SS group received intrathecal catheterization one week before SMIR, the SS group was injected with 20 µl of IRF8 SiRNA solution (dissolved in DEPC-treated water, 150 pmol) intrathecally on the 5th and 6th day after SMIR, and the SD group was injected with the same amount of DEPC-treated water. The paw withdrawal threshold (PWT) of each group was measured and recorded before SMIR and on the 1st, 3rd, 7th, 12th, 22nd and 33rd days after SMIR. Western blot was used to detect the expression of Iba-1 in the dorsal horn of spinal cord on the 12th days after SMIR, and the saphenous nerves in the SH group and SM group were collected to observe their ultrastructural changes under electron microscope. The flow cytometry was used to detect the activation of microglia in spinal cord dorsal horn before SMIR and on the 1st, 3rd, 7th, 12th, 22nd and 33rd days after SMIR in the SM group and SS group. Results: Compared with D0, the PWT of SM group was decreased on the 1th to 22nd day after SMIR (P＜0.05 or P＜0.01), and returned to normal level on the 33rd day after SMIR (P＞ 0.05). Compared with the SH group, the PWT of the SM group was decreased on the 1th to 22nd day after SMIR (P＜0.05 or P＜ 0.01). However, compared with the SD group, the PWT of the SS group was increased on the 7th to 22nd day after SMIR (P＜0.05 or P＜0.01). Compared with SH group, the PWT of SS group was decreased on the 7th to 22nd day after SMIR (P＜0.05 or P＜0.01). The average thickness of saphenous nerve myelin was (377.0 3±69.60) nm in the SH group and (369.50±73.26) nm in the SM group, and there was no significant difference between the two groups (P＞0.05). Compared with the SH group, the expression level of Iba-1 was increased significantly (P＜0.01) in the SM group. Compared with the SD group, the expression of Iba-1 was inhibited (P＜0.05) in the SS group, and compared with the SH group, the expression of Iba-1 was also statistically different (P＜0.05) in the SS group, while the expression of Iba-1 was not statistically significant between the SM group and the SD group (P＞0.05). Compared with D0, the activation ratio of microglia was increased significantly on the 3rd to 22nd day after SMIR (P＜0.01) in the SM group , while the activation of microglia reached a peak on 3rd day after SMIR (P＜0.01) in the SS group. After intrathecal administration, the activation rate of microglia in the spinal dorsal horn of the SS group was decreased significantly, and compared with the SM group, it was decreased significantly on the 7th to 12th day after SMIR (P＜0.01). Conclusion: The significant and persistent mechanical hyperalgesia in PPsP induced by SMIR was caused non-obvious peripheral nerve injury, which may be mediated by the activation of microglia in the dorsal horn of the spinal cord. IRF8 SiRNA administrated by intrathecal injection could inhibit the activation of microglia and reverse SMIR-induced hyperalgesia.

Perioperative medicine role in painful knee prosthesis prevention.

Total knee arthroplasty is one of the most frequently performed orthopaedic surgeries. However, up to 20% of patients develop persistent postoperative pain. Persistent postoperative pain may be an extension of acute postoperative pain, but can also occur after more than 3 months without symptoms. Risk factors associated with persistent postoperative pain after arthroplasty have now been characterised within the patient's perioperative context (preoperative, intraoperative and postoperative), and can be grouped under genetic, demographic, clinical, surgical, analgesic, inflammatory and psychological factors. Identification and prevention of persistent postoperative pain through a multimodal and biopsychosocial approach is essential in the context of perioperative medicine, and has been shown to prevent or ameliorate postoperative pain.

The Perioperative Pain Self-Management (PePS) randomized controlled trial protocol: Preventing chronic post-surgical pain and prolonged opioid use.

BACKGROUND: Total joint arthroplasties are common orthopedic surgeries that carry risk for developing chronic post-surgical pain. In addition to pre- and post-operative pain severity, psychological distress (e.g., anxiety, pain catastrophizing) is a risk factor for chronic postsurgical pain. Cognitive behavioral therapy (CBT) for chronic pain is an empirically supported approach to managing chronic pain, functional impairment, and related distress. While CBT has been used extensively in patients with established chronic pain, using it as a preventive intervention targeting the transition from acute to chronic postsurgical pain is a novel application. OBJECTIVES: The Perioperative Pain Self-Management (PePS) program is a pain self-management intervention based on the principles of CBT. This innovative intervention is brief, flexible, and is delivered remotely. The current study aims to determine the efficacy of PePS compared to standard care on reducing the incidence of significant surgical site pain at 6-months post-surgery. The current study also aims to evaluate the context for subsequent implementation. METHODS: This study is a hybrid type I efficacy-preparing for implementation trial. It is a two-site, single-blind, two-arm, parallel, randomized control trial. Surgical patients will be randomized to either receive: 1) PePS plus standard care, or 2) Standard care. The primary end point will be surgical site pain severity at 6-months post-surgery. CONCLUSION: Results from this study are expected to result in support for a brief scalable intervention (PePS) that can prevent the development of chronic pain and prolonged post-surgical opioid use, as well as key details to inform subsequent implementation. CLINICALTRIALS: govIdentifier:NCT04979429.

Reimagining How We Treat Acute Pain: A Narrative Review.

Acute pain may be influenced by biopsychosocial factors. Conditioned pain modulation, distraction, peripheral nerve stimulation, and cryoneurolysis may be helpful in its treatment. New developments in opioids, such as opioids with bifunctional targets and oliceridine, may be particularly suited for acute pain care. Allosteric modulators can enhance receptor subtype selectivity, offering analgesia with fewer and/or less severe side effects. Neuroinflammation in acute pain is caused by direct insult to the central nervous system and is distinct from neuroinflammation in degenerative disorders. Pharmacologic agents targeting the neuroinflammatory process are limited at this time. Postoperative pain is a prevalent form of acute pain and must be recognized as a global public health challenge. This type of pain may be severe, impede rehabilitation, and is often under-treated. A subset of surgical patients develops chronic postsurgical pain. Acute pain is not just temporally limited pain that often resolves on its own. It is an important subject for further research as acute pain may transition into more damaging and debilitating chronic pain. Reimagining how we treat acute pain will help us better address this urgent unmet medical need.

Perioperative prevention of persistent pain after total hip and knee arthroplasty-Protocol for two systematic reviews.

BACKGROUND: Between 9% and 20% of patients experience moderate to severe persistent postoperative pain after total hip or knee arthroplasty. Severe immediate postoperative pain limits rehabilitation and is associated with the development of persistent postoperative pain. Therefore, perioperative analgesic and physiotherapeutic interventions are of interest to reduce persistent pain. In two systematic reviews with identical methodology, we aim to investigate the effects of (a) perioperative analgesic interventions and (b) physiotherapeutic interventions in reducing persistent pain after total hip and knee arthroplasty. METHODS: We will include randomised and cluster-randomised controlled trials on perioperative analgesic and physiotherapeutic interventions for patients undergoing elective total hip or knee arthroplasty for osteoarthritis. After contact with the authors, trials without pain data 3-24 months postoperatively will be excluded. Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase and reference lists will be searched for eligible trials. Two authors will independently screen, extract data and assess the risk of bias. The primary outcome is pain scores 3-24 months postoperatively. Meta-analyses will be performed for interventions with two or more trials. We will conduct trial sequential analyses and assign Grading of Recommendations, Assessment, Development and Evaluation (GRADE) ratings. CONCLUSION: No previous review on reduction of persistent postoperative pain has included non-pharmacological or invasive analgesic techniques. These two reviews with identical methodology will summarise the evidence of analgesic and physiotherapeutic perioperative interventions to prevent persistent pain. PROSPERO REGISTRATION: CRD42021284175.

A retrospective study on patients with chronic knee pain treated with ultrasound-guided radiofrequency of the genicular nerves (RECORGEN trial).

INTRODUCTION: Radiofrequency (RF) treatment of the genicular nerves is a promising treatment for chronic osteoarthritic and persistent postsurgical knee pain (PPSP), refractory to conventional medical management. METHODS: The RECORGEN study is a retrospective single-center cohort study of patients treated with ultrasound-guided conventional RF of the genicular nerves for chronic knee pain in Hospital Oost-Limburg, Genk from September 2017 to June 2020. Subgroup analysis based on etiology of pain (PPSP and degenerative knee pain) was performed in addition to the total study population analysis. Outcome parameters were global perceived effect (GPE), Numeric Rating Scale for pain, consumption of strong opioids, and safety of the treatment at 6 weeks and cross-sectionally at a variable time point. Treatment success was defined as GPE≥50%. RESULTS: Sixty-eight cases were screened of which 59 (46 diagnosed with PPSP and 13 with degenerative knee pain) were included in the study. Treatment success at 6 weeks was achieved in 19 of 59 interventions (32.2%) and was similar in both groups. Seventeen responders were evaluated at follow-up. 45.1% (8/17) continued to have a positive effect at the second time point. The mean duration of effect of the RF treatment was 8.3 months. Safety analysis at 6 weeks and at the second time point showed a good safety profile of the treatment. CONCLUSION: Conventional RF of the genicular nerves was clinically successful in more than 30% of the study population refractory to conventional medical management. Overall, the treatment was well tolerated. The mean duration of effect was 8.3 months.