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This review investigates how EA addresses preoperative anxiety-induced postoperative hyperalgesic priming ie pain chronification, focusing on its mechanisms in three areas: preoperative anxiety, postoperative hyperalgesic priming, and the interaction between EA and these processes. Methods: A literature search across PubMed, ScienceDirect, and Google Scholar identified relevant studies on EA's effects on neurobiological pathways related to anxiety and pain. The review synthesized findings to understand EA's role in these contexts. Results: EA alleviates preoperative anxiety by influencing the body's neurochemical and neurophysiological responses. It reduces inflammation, regulates stress hormones, and improves autonomic function. For postoperative pain chronification, EA modulates pain pathways, reduces inflammation, and affects receptor signaling, gene expression, and neurotransmitter systems. Conclusion: EA offers a promising approach to managing preoperative anxiety and postoperative pain. By addressing both the physiological and neurochemical pathways that contribute to pain and anxiety, EA has the potential to significantly improve clinical outcomes for patients undergoing surgery. Further research is needed to fully understand its mechanisms and optimize its application in clinical settings. [ABSTRACT FROM AUTHOR]

Purpose: Currently, inguinal hernias are highly prevalent in the Brazilian population, accounting for 75% of all abdominal wall hernias. The recommended treatment to correct them is inguinal herniorrhaphy, which can be performed through open surgery, mainly using the Lichtenstein technique, or laparoscopically, primarily through Transabdominal Preperitoneal Repair (TAPP) or Total Extraperitoneal Repair (TEP) approaches. Like any surgery, these procedures have post-operative complications, with pain being the most common and debilitating. Currently, in European and Brazilian guidelines, the open Lichtenstein and endoscopic inguinal hernia techniques are recommended as best evidence-based options for repair of a primary unilateral hernia providing the surgeon is sufficiently experienced in the specific procedure. In that matter, the surgeon should make a choice based on assessment of the benefits and risks of performing each of them, and practice shared making decision with it patient. Therefore, the objective of this review was to assess the incidence of chronic postoperative pain by comparing the aforementioned surgical approaches to evaluate which procedure causes less disability to the patient. Methods: The search conducted until May 2024 was performed on Medline (PubMed), Cochrane (CENTRAL), and Lilacs databases. The selection was limited to randomized clinical trials, nonrandomized clinical trials and cohort studies comparing TAPP or TEP to LC, evaluating the incidence of chronic postoperative pain published between 2017 and 2023. Evidence certainty was assessed using the GRADE Pro tool, and bias risk was evaluated with the RoB 2.0 tool and ROBINS I tool. Thirteen studies were included. Results: The meta-analysis showed a significant difference between the groups in both techniques, favoring the laparoscopic approach, which had a lower occurrence of postoperative inguinodynia with a relative risk of 0.49 (95% CI = 0.32, 0.75; I2 = 66% (P = 0.001); Z = 3.28 (P = 0.001) with low certainty of evidence. Conclusion: The presence of chronic postoperative pain was lower in laparoscopic TEP/TAPP techniques when compared to the open Lichtenstein technique, meaning that the former can bring more benefits to patients who requires inguinal herniorrhaphy. Nevertheless, further randomized clinical trials are needed to optimize the analysis, minimizing the bias. [ABSTRACT FROM AUTHOR]

Objective: Studies have shown that chemokines can stimulate the migration and activation of microglia to cause chronic post-surgical pain (CPSP). However, the involvement of C-X-C motif chemokine receptor 2 (CXCR2) as a new chemotactic factor in regulating CPSP and its underlying mechanism remains unclear. This study is to investigate the role of CXCR2 in the development of CPSP and reveal the underlying mechanism. Material and Methods: A rat model of skin/muscle incision and retraction was established, and treated with or without SB225002 (a selective inhibitor of CXCR2). In addition, the primary microglia cells induced by lipopolysaccharide were applied as an in vitro model for CPSP and treated individually with si-negative control (NC), si-CXCR2, si-CXCR2+Interleukin (IL)-6 (an agonist of the janus kinase (JAK)/signal transducers and activators of transcription (STAT)3 signaling pathway), si-CXCR2+IL-6+si-NC, or si-CXCR2+IL-6+si-exchange protein 1 directly activated by cAMP (EPAC1). Results: Results from the database analysis showed that CXCR2 and JAK/STAT3 signaling pathway-related genes, including JAK1, STAT3, and EPAC1, were mainly involved in the development of CPSP. Inhibition of CXCR2 expression not only inhibited the reduction of foot pain threshold in CPSP models but also led to a decreased expression of CXCR2 and the phosphorylation levels of JAK and STAT3 in both animal and cell models. Furthermore, inhibition of EPAC1 expression can hinder the regulatory function of CXCR2. Conclusion: This study indicated that the high expression of CXCR2 activates the JAK1/STAT3 signaling pathway, enhances EPAC1 activation in microglial cells, and exacerbates CPSP. [ABSTRACT FROM AUTHOR]

The objective of this study is to determine whether the change in pain intensity over time differs between somatosensory functioning evolution profiles in knee osteoarthritis (KOA) patients undergoing total knee arthroplasty (TKA). This longitudinal prospective cohort study, conducted between March 2018 and July 2023, included KOA patients undergoing TKA in four hospitals in Belgium and the Netherlands. The evolution of the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscale pain over time (baseline, 3 months, and 1 year post-TKA scores) was the outcome variable. The evolution scores of quantitative sensory testing (QST) and Central Sensitization Inventory (CSI) over time (baseline and 1 year post-TKA scores) were used to make subgroups. Participants were divided into separate normal, recovered, and persistent disturbed somatosensory subgroups based on the CSI, local and widespread pressure pain threshold [PPT] and heat allodynia, temporal summation [TS], and conditioned pain modulation [CPM]. Linear mixed model analyses were performed. Two hundred twenty-three participants were included. The persistent disturbed somatosensory functioning group had less pronounced pain improvement (based on CSI and local heat allodynia) and worse pain scores 1 year post-TKA (based on CSI, local PPT and heat allodynia, and TS) compared to the normal somatosensory functioning group. This persistent group also had worse pain scores 1 year post-TKA compared to the recovered group (based on CSI). The study suggests the presence of a "centrally driven central sensitization" subgroup in KOA patients awaiting TKA in four of seven grouping variables, comprising their less pain improvement or worse pain score after TKA. Future research should validate these findings further. The protocol is registered at clinicaltrials.gov (NCT05380648). [ABSTRACT FROM AUTHOR]

ObjectiveTo explore the incidence and influencing factors of subacute and chronic pain in patients returning to the ICU after surgery, provide diagnostic and therapeutic insights for the evaluation and management of such patients, and improve the prognosis of this population.MethodsPatients who underwent surgical treatment and returned to the ICU from November 29, 2021 to December 31, 2021 at Peking Union Medical College Hospital were prospectively recruited. Subacute and chronic pain incidence and characteristics were assessed by telephone at 1 and 3 months after surgery and the influencing factors were further explored.ResultsA total of 117 patients were enrolled, with an average age of 60.9±16.0 years. The incidence of subacute postoperative pain in patients returning to the ICU after surgery was 45.7%(53/116), and the incidence of chronic postoperative pain in patients returning to the ICU after surgery was 32.7%(36/110). The mean NRS for moderate to severe subacute pain and chronic pain after surgery were(4.9±1.2) and (5.2±1.1), respectively. Multivariable logistic regression analysis showed that coronary artery disease (OR=5.263, 95% CI: 1.436-19.292)was risk factor for chronic postoperative pain in patients returning to the ICU after surgery.ConclusionsPatients returning to the ICU after surgery have a high incidence of postoperative subacute and chronic pain. Coronary artery disease was the risk factor for chronic pain.Perioperative multimodal pain management can be used to improve the pain experience of patients during ICU hospitalization and the short-term and long-term prognosis of patients.

The International Association for the Study of Pain defines pain as «an unpleasant sensory and emotional experience associated with, or described in terms of, actual or potential tissue damage». The management of refractory chronic pain is complex. Intrathecal therapy is considered a safe and effective treatment. However, the psychological and social impact also needs to be considered. Ziconotide is an intrathecal drug and a first-line treatment for refractory chronic pain. We present the case of a patient with neuropathic pain after resection of an ependymoma and disc herniation. After failure of pharmacological therapy and spinal cord stimulation, it was decided to implant an intrathecal ziconotide infusion pump. Despite clinical improvement, the patient developed an anxious-depressive disorder and considered euthanizing. The patient was treated with acceptance and commitment therapy, showed improvement in the emotional scale and physical activity, and refused the request for euthanasia. [ABSTRACT FROM AUTHOR]

The objective of this peripheral nerve stimulation consensus guideline is to add to the current family of consensus practice guidelines and incorporate a systematic review process. The published literature was searched from relevant electronic databases, including PubMed, Scopus, Cochrane Central Register of Controlled Trials, and Web of Science from database inception to March 29, 2021. Inclusion criteria encompassed studies that described peripheral nerve stimulation in patients in terms of clinical outcomes for various pain conditions, physiological mechanism of action, surgical technique, technique of placement, and adverse events. Twenty randomized controlled trials and 33 prospective observational studies were included in the systematic review process. There is Level I evidence supporting the efficacy of PNS for treatment of chronic migraine headaches via occipital nerve stimulation; chronic hemiplegic shoulder pain via stimulation of nerves innervating the trapezius, supraspinatus, and deltoid muscles; failed back surgery syndrome via subcutaneous peripheral field stimulation; and lower extremity neuropathic and lower extremity post-amputation pain. Evidence from current Level I studies combined with newer technologies facilitating less invasive and easier electrode placement make peripheral nerve stimulation an attractive alternative for managing patients with complex pain disorders. Peripheral nerve stimulation should be used judiciously as an adjunct for chronic and acute postoperative pain following adequate patient screening and positive diagnostic nerve block or stimulation trial.

Xiaomei Dai,1 Meijuan Yuan,1 Mengbo Dang,2 Dianwei Liu,2 Wenyong Fei3 1School of Nursing and School of Public Health, Yangzhou University, Yangzhou, People’s Republic of China; 2Dalian Medical University, Dalian, People’s Republic of China; 3Department of Orthopedics and Sports Medicine, Northern Jiangsu People’s Hospital, Affiliated to Yangzhou University, Yangzhou, People’s Republic of ChinaCorrespondence: Wenyong Fei, Department of Orthopedics and Sports medicine, Northern Jiangsu People’s Hospital, Affiliated to Yangzhou University, Yangzhou, 225001, People’s Republic of China, Tel +86 18051061779, Email sbydyx105@163.comPurpose: Chronic pain management continues to present a significant challenge following arthroscopic shoulder surgery. Our purpose was to detect chronic postsurgical pain (CPSP) in patients who had undergone arthroscopic rotator cuff repair (ARCR) and develop a nomogram capable of predicting the associated risk.Patients and Methods: We collected the demographic and clinical data of 240 patients undergoing ARCR in our hospital from January 2021 to May 2022. The pain level was monitored and evaluated three months after ARCR. LASSO regression was used to screen out pain-predicting factors, which were subsequently used to construct a nomogram. Internal validation was carried out using Bootstrap resampling. The data of 78 patients who underwent ARCR in our hospital from August 2022 to December 2022 were also collected for external verification of the nomogram. The predictive model was evaluated using the receiver operating characteristic curve (ROC), calibration curve, and decision curve analysis (DCA).Results: Age, duration of preoperative shoulder pain (DPSP), C-reactive protein (CRP), number of tear tendons, and American Shoulder and Elbow Surgical Score (ASES) were screened by LASSO regression as predictive factors for CPSP. These factors were then used to construct a chronic pain risk nomogram. The area under the curve (AUC) of the predictive and validation models were 0.756 (95% CI: 0.6386– 0.8731) and 0.806 (95% CI: 0.6825– 0.9291), respectively. Furthermore, the calibration curves and decision curve analysis (DCA) for both models indicated strong performance, affirming the reliability of this predictive model.Conclusion: The CPSP risk model that has been developed exhibits strong predictive capabilities and practical utility. It offers valuable support to clinical healthcare professionals in making informed treatment decisions, reducing the unnecessary use of analgesic drugs, and optimizing the allocation of medical resources.Keywords: arthroscopic rotator cuff repair, chronic postoperative pain, nomogram, predictive model, risk factors

Abstract Introduction The evolution of pre- versus postoperative risk factors remains unknown in the development of persistent postoperative pain and opioid use. We identified preoperative versus comprehensive perioperative models of delayed pain and opioid cessation after total joint arthroplasty including time-varying postoperative changes in emotional distress. We hypothesized that time-varying longitudinal measures of postoperative psychological distress, as well as pre- and postoperative use of opioids would be the most significant risk factors for both outcomes. Methods A prospective cohort of 188 patients undergoing total hip or knee arthroplasty at Stanford Hospital completed baseline pain, opioid use, and emotional distress assessments. After surgery, a modified Brief Pain Inventory was assessed daily for 3 months, weekly thereafter up to 6 months, and monthly thereafter up to 1 year. Emotional distress and pain catastrophizing were assessed weekly to 6 months, then monthly thereafter. Stepwise multivariate time-varying Cox regression modeled preoperative variables alone, followed by all perioperative variables (before and after surgery) with time to postoperative opioid and pain cessation. Results The median time to opioid and pain cessation was 54 and 152 days, respectively. Preoperative total daily oral morphine equivalent use (hazard ratio-HR 0.97; 95% confidence interval-CI 0.96–0.98) was significantly associated with delayed postoperative opioid cessation in the perioperative model. In contrast, time-varying postoperative factors: elevated PROMIS (Patient-Reported Outcomes Measurement Information System) depression scores (HR 0.92; 95% CI 0.87–0.98), and higher Pain Catastrophizing Scale scores (HR 0.85; 95% CI 0.75–0.97) were independently associated with delayed postoperative pain resolution in the perioperative model. Conclusions These findings highlight preoperative opioid use as a key determinant of delayed postoperative opioid cessation, while postoperative elevations in depressive symptoms and pain catastrophizing are associated with persistent pain after total joint arthroplasty providing the rationale for continued risk stratification before and after surgery to identify patients at highest risk for these distinct outcomes. Interventions targeting these perioperative risk factors may prevent prolonged postoperative pain and opioid use.

Chronic postoperative pain (CPOP) is a potentially devastating consequence of a surgical procedure. It leads to increased medical costs, painful, and stress experience to the patients. After a surgical decompression performed in a patient with a non-traumatic compartment syndrome, a muscle biopsy confirmed McArdle disease, and after surgery, severe pain of neuropathic characteristics developed in the arm decompressed. Advanced techniques up to neuromedullary stimulation failed to improve the clinical status, after which repeated treatment with capsaicin patch ameliorated the patient's condition. This case report illustrates the need for a high index of suspicion for metabolic diseases in patients who present compartment syndrome without prior history of trauma and also the challenges in treating neuropathic pain after surgery.

Up to 20% of total knee arthroplasty (TKA) patients continue to experience chronic postsurgical pain. Various factors have been identified as potential contributors, including so-called "yellow flags", encompassing symptoms of depression, anxiety, and catastrophizing, which were examined in this study to assess their predictive value concerning functional outcomes after TKA. Methods: Fifty TKA patients were categorized into high-risk and low-risk groups based on clinical assessment, demographic data, medication, and patient-reported outcome measures (DN4, SF-36, WOMAC, NRS, Fibromyalgia Survey Questionnaire, Pain Catastrophizing Scale, and Hospital Anxiety and Depression Scale). Postoperative outcomes within six months after TKA were then compared. Results: Both groups exhibited significant (p < 0.001) improvements in all WOMAC and NRS subscales, as well as in the physical function, role physical, pain, and energy/fatigue subdomains of the SF-36 after six months, while the high-risk group showed lower WOMAC scores regarding stiffness (19.0 ± 18.3 vs. 27.2 ± 20.7, p < 0.001) and pain (13.5 ± 13.3 vs. 15.1 ± 16.3, p = 0.029). The high-risk group showed significantly worse preoperative DN4 scores (1.8 ± 1.3 vs. 3.0 ± 1.1, p = 0.002) than the low-risk group, which persisted for one day (2.3 ± 1.2 vs. 3.5 ± 1.5, p = 0.005) and six weeks (2.2 ± 1.9 vs. 3.6 ± 2.3, p = 0.041) postoperatively. Conclusions: Our results indicate that pre-existing yellow flags contribute to a more challenging early postoperative phase, underscoring the importance of considering individual patient characteristics and psychological factors to optimize TKA outcomes. [ABSTRACT FROM AUTHOR]

Chronic postsurgical pain (CPSP) is a prevalent condition that can diminish health-related quality of life, cause functional deficits, and lead to patient distress. Rates of CPSP are higher for certain types of surgeries than others (thoracic, breast, or lower extremity amputations) but can occur after even uncomplicated minimally invasive procedures. CPSP has multiple mechanisms, but always starts as acute postsurgical pain, which involves inflammatory processes and may encompass direct or indirect neural injury. Risk factors for CPSP are largely known but many, such as female sex, younger age, or type of surgery, are not modifiable. The best strategy against CPSP is to quickly and effectively treat acute postoperative pain using a multimodal analgesic regimen that is safe, effective, and spares opioids. This is a narrative review of the literature. Every surgical patient is at some risk for CPSP. Control of acute postoperative pain appears to be the most effective approach, but principles of good opioid stewardship should apply. The role of regional anesthetics as analgesics is gaining interest and may be appropriate for certain patients. Finally, patients should be better informed about their relative risk for CPSP. The majority of surgery patients experience pain right after surgery that diminishes day by day as the tissue heals. Surgeons can usually advise patients how long their postsurgical pain will last, but in some cases, pain persists much longer and can even become chronic. Chronic postsurgical pain or CPSP is a condition that occurs most often in people who have open-chest surgery, breast surgery, or have a lower limb amputated. However, CPSP can occur after any type of surgery, even minimally invasive procedures with no complications. CPSP is a form of chronic pain and can be treated as chronic pain. CPSP can be mild or severe. In some patients, CPSP can include a form of numbness or 'pins and needles' around the affected area. There are certain things that can increase a person's risk for developing CPSP. Some of these things cannot be changed, like the higher risk for females, younger people, and for certain types of surgery. Pre-existing pain before surgery can increase the risk of CPSP and so can having a very negative attitude called 'catastrophizing.' People who 'catastrophize' tend to focus and think constantly about worst-case scenarios. Genetics may also play a role in CPSP, but less is known about what genes are involved and how to reduce the risk. Some CPSP is unavoidable, such as a surgery that might cut or compress a nerve. In other cases, the inflammation following surgery can set the stage for CPSP. The best strategy to prevent or minimize CPSP is for the clinical team to effectively treat the acute postsurgical pain.] The recommended approach is to use a multimodal pain therapy which is based on two or more agents and may also combine nonpharmacologic approaches as well. Multimodal pain care solves two pain problems. First, CPSP tends to be different types of pain that occur together in something called a 'mixed pain syndrome.' Multimodal pain treatment uses more than one agent with different mechanisms of action. Second, multimodal pain regimens reduce or may even eliminate the use of opioid pain relievers. By using the lowest effective amount of opioids, patients are spared opioid-associated side effects and fewer opioids are used. Opioids are associated with opioid use disorder and new policies about good opioid stewardship urge hospitals and prescribers to use opioids only to the extent appropriate. [ABSTRACT FROM AUTHOR]

Chronic postoperative pain (CPP) in mesh hernia repair (MHR) may complicate the postoperative course. The cause of CPP may be multifactorial - surgical technique, patient-intrinsic factors, and mesh. Polypropylene (PP) mesh is the most widely used material for MHR. Despite its advantages, it has been associated with severe complications in urogynecology leading to a partial mesh ban. PP is not inert and causes foreign body reactions (FBR), corrosion, and loss in biocompatibility. Pain is a hallmark of mesh-induced complications. The pathogenesis of pain is related to an immune response with neutrophils, T cells, and macrophages, major players in mesh-associated fibrosis and pain. Pain may be caused by mesh implantation-induced nerve entrapment, compression, and severe inflammation, relevant for both nociceptive and neuropathic pain. Compression neuropathy has been associated with preoperative pain and chronic postoperative pain in mesh and non-mesh repairs. The mesh may induce FBR changes causing clinical complications and pain. Increased mesh vicinity innervation induced by fibrosis may be responsible for chronic postoperative pain. An aggressive immune response in pelvic floor reconstructive surgery degrades PP. T cells and macrophages may protect against or induce degradation and pain. The main point to eliminate pain is to develop a mesh, that provides long-term corrosion resistance, and biocompatibility. This may be achieved by coating PP mesh with a thin layer of Titanium oxide or meshes of pure titanium. Titanium is considered to be bio-inert providing corrosion resistance and biocompatibility. However, depending on the location and surface of the mesh (roughness, hydrophilicity), there may be a macrophageneutrophil-induced inflammatory response causing fibrosis and cicatrization. Based on the structure, location, and production Titanium may demonstrate beneficial effects concerning corrosion, oxidation, FBR, and biocompatibility. To improve outcomes in MHR the analysis of cellular immune response concerning mesh properties, composite endpoints, pain, and physical function may be necessary. [ABSTRACT FROM AUTHOR]

Introduction: The evolution of pre- versus postoperative risk factors remains unknown in the development of persistent postoperative pain and opioid use. We identified preoperative versus comprehensive perioperative models of delayed pain and opioid cessation after total joint arthroplasty including time-varying postoperative changes in emotional distress. We hypothesized that time-varying longitudinal measures of postoperative psychological distress, as well as pre- and postoperative use of opioids would be the most significant risk factors for both outcomes. Methods: A prospective cohort of 188 patients undergoing total hip or knee arthroplasty at Stanford Hospital completed baseline pain, opioid use, and emotional distress assessments. After surgery, a modified Brief Pain Inventory was assessed daily for 3 months, weekly thereafter up to 6 months, and monthly thereafter up to 1 year. Emotional distress and pain catastrophizing were assessed weekly to 6 months, then monthly thereafter. Stepwise multivariate time-varying Cox regression modeled preoperative variables alone, followed by all perioperative variables (before and after surgery) with time to postoperative opioid and pain cessation. Results: The median time to opioid and pain cessation was 54 and 152 days, respectively. Preoperative total daily oral morphine equivalent use (hazard ratio-HR 0.97; 95% confidence interval-CI 0.96–0.98) was significantly associated with delayed postoperative opioid cessation in the perioperative model. In contrast, time-varying postoperative factors: elevated PROMIS (Patient-Reported Outcomes Measurement Information System) depression scores (HR 0.92; 95% CI 0.87–0.98), and higher Pain Catastrophizing Scale scores (HR 0.85; 95% CI 0.75–0.97) were independently associated with delayed postoperative pain resolution in the perioperative model. Conclusions: These findings highlight preoperative opioid use as a key determinant of delayed postoperative opioid cessation, while postoperative elevations in depressive symptoms and pain catastrophizing are associated with persistent pain after total joint arthroplasty providing the rationale for continued risk stratification before and after surgery to identify patients at highest risk for these distinct outcomes. Interventions targeting these perioperative risk factors may prevent prolonged postoperative pain and opioid use. [ABSTRACT FROM AUTHOR]

Purpose: Chronic pain following breast surgery is a concern for breast cancer survivors; however, few studies have investigated the localization of persistent postoperative pain. We conducted this study to identify the location of pain following breast reconstruction. Methods: A total of 213 Japanese women undergoing mastectomy only or breast reconstruction with a tissue expander/implant (TE/Imp) or a deep inferior epigastric perforator (DIEP) flap were enrolled in the study. Questionnaires related to pain location were sent to patients at the end of postoperative year (POY) 1 and POY 5. Multiple comparisons of the types of operation and cross-tabulation were made between the two time points. Results: Surveys were completed by 107 of the women. Severe pain in the upper medial breast was significantly more common in POY 1 after DIEP reconstruction than after mastectomy only (P = 0.01), whereas abdominal pain was worse in POY 5 after DIEP reconstruction than after mastectomy only (P = 0.04). Pain in the medial arm and axilla had resolved better after TE/Imp (P = 0.03) and DIEP reconstruction (P = 0.01) than after mastectomy only by POY 5, but the difference between TE/Imp and DIEP reconstruction was not significant. Conclusions: These results show that localization of prolonged postoperative pain following breast reconstruction differs depending on the surgical strategy. [ABSTRACT FROM AUTHOR]

Chronic postoperative pain (CPOP) is a serious health issue that affects millions of patients every year. The incidence of CPOP is the highest after amputations, inguinal hernioplasty, thoracotomies, cardiac surgery and breast surgery. In addition to surgical factors, the other risk factors are: female gender, younger age, preoperative pain, psychological state and acute postoperative pain. The most common expression of CPOP is neuropathic pain after surgical trauma. The treatment of chronic postoperative neuropathic pain (CPNP) is difficult. Various methods have been recommended for its prevention, the most important being techniques that avoid nerve damage and adequate perioperative analgesia. The goal of this review was to discuss data from published studies examining the incidence, risk factors and mechanisms of CPOP, with a focus on surgery, the unique opportunity to implement pharmacological strategies for prevention of CPNP and current pharmacotherapy approaches for treatment of CPNP. Commonly used drugs to prevent and treat CPNP in the current clinical setting are: opioids, α2-adrenergic agonists, cyclooxygenase antagonists, gabapentin, pregabalin, steroids, N-methyl-D-aspartate receptor antagonists and local anesthetics.

Chronic post-surgical pain is a relatively common adverse effect following surgery. Several prognostic factors for chronic post-surgical pain have been identified, including psychological states and traits. Psychological factors are modifiable, and perioperative psychological interventions may reduce the incidence of chronic post-surgical pain. A meta-analysis showed preliminary evidence for the benefits of such interventions for the prevention of chronic post-surgical pain. Further research must be conducted to better understand the specific type, intensity, duration and timing of interventions that are most effective. The number of studies in this area has recently increased, with additional randomised controlled trials currently being carried out, which may allow for the development of more robust conclusions in the coming years. In order to implement perioperative psychological care alongside routine surgical interventions, efficient and accessible interventions should be available. In addition, demonstration of cost-effectiveness may be a prerequisite for wider adoption of perioperative psychological interventions in regular healthcare. Offering psychological interventions selectively to patients at risk of chronic post-surgical pain could be a means to increase cost-effectiveness. Stepped-care approaches should also be considered, where the intensity of psychological support is adapted to the needs of the patient. [ABSTRACT FROM AUTHOR]

Chronic postoperative pain (CPOP) is a potentially devastating consequence of a surgical procedure. It leads to increased medical costs, painful, and stress experience to the patients. After a surgical decompression performed in a patient with a non-traumatic compartment syndrome, a muscle biopsy confirmed McArdle disease, and after surgery, severe pain of neuropathic characteristics developed in the arm decompressed. Advanced techniques up to neuromedullary stimulation failed to improve the clinical status, after which repeated treatment with capsaicin patch ameliorated the patient's condition. This case report illustrates the need for a high index of suspicion for metabolic diseases in patients who present compartment syndrome without prior history of trauma and also the challenges in treating neuropathic pain after surgery. [ABSTRACT FROM AUTHOR]

Shoulder arthroplasty is a successful surgical procedure for several conditions when patients become refractory to conservative management modalities. Unfortunately, some patients experience persistent chronic pain after shoulder arthroplasty. These individuals should undergo a comprehensive evaluation by an orthopedic surgeon to determine whether structural pathology is responsible for the pain and to decide whether reoperation is indicated. At times, a surgical solution does not exist. In these circumstances, a thorough and specific plan for the management of persistent chronic pain should be developed and instituted. In this article, we review common reasons for persistent pain after shoulder arthroplasty and outline the evaluation of the painful shoulder arthroplasty. We then provide a thorough review of interventional pain management strategies. Finally, we hypothesize developments in our field that might provide better outcomes in the future for patients suffering with chronic intractable pain after shoulder arthroplasty.

Abstract Background Thoracoscopic radical pneumonectomy is associated with a high incidence of postoperative chronic pain. Studies on the benefits of lidocaine intravenous infusion during the perioperative period were still controversial in thoracoscopic surgery. Methods Sixty-four lung cancer patients scheduled for thoracoscopic radical pneumonectomy were randomly divided into two groups: normal saline group (control group) or lidocaine group. In the lidocaine group, 1.5 mg/kg lidocaine was administered during the anesthesia induction, and 2 mg·kg−1·h−1 lidocaine was continuously intravenous infused until the end of the surgery. After the surgery, a mixture of 2 μg/kg sufentanil and 10 mg/kg lidocaine was continuously intravenous infused by postoperative patient-controlled intravenous analgesia pump (100 ml). In the control group, the same volume of normal saline was administered according to the calculation of lidocaine during anesthesia induction, maintenance and postoperative patient-controlled intravenous analgesia. The primary outcome was the incidence of chronic postoperative pain at 3 months after the surgery. The secondary outcomes include the incidence of chronic postoperative pain at 6 months after the surgery; the effect of lidocaine on postoperative pain within the first 24 and 48 h; total amount of sufentanil administered during entire procedure and the number of PCA triggers within 48 h after surgery. Results Compared with the control group, the incidence of chronic pain at 3 months after the surgery was significantly lower (13 cases, 46.4% vs. 6 cases, 20.7%, p

Natalie Strand,1 Ryan S D’Souza,2 Jonathan M Hagedorn,3 Scott Pritzlaff,4 Dawood Sayed,5 Nomen Azeem,6 Alaa Abd-Elsayed,7 Alexander Escobar,8 Mark A Huntoon,9 Christopher M Lam,5 Timothy R Deer10 1Department of Anesthesiology, Division of Pain Medicine, Mayo Clinic, Scottsdale, AZ, USA; 2Department of Anesthesiology and Perioperative Medicine, Division of Pain Medicine, Mayo Clinic, Rochester, MN, USA; 3iSpine Pain Physicians, Burnsville, MN, USA; 4Department of Anesthesiology and Pain Medicine, Division of Pain Medicine, University of California-Davis, Sacramento, CA, USA; 5The University of Kansas Medical Center, Kansas City, KS, USA; 6Florida Spine & Pain Specialists, Bradenton, FL, USA; 7Department of Anesthesiology, University of Wisconsin, Madison, WI, USA; 8Comprehensive Centers for Pain Management, Toledo, OH, USA; 9Department of Anesthesiology, Virginia Commonwealth University, Henrico, VA, USA; 10The Spine and Nerve Center of the Virginias, Charleston, WV, USACorrespondence: Natalie Strand, Department of Anesthesiology, Division of Pain Medicine, Mayo Clinic, Scottsdale, AZ, USA, Tel +1 480-301-8000, Fax +1 480-342-2986, Email strand.natalie@mayo.eduAbstract: The objective of this peripheral nerve stimulation consensus guideline is to add to the current family of consensus practice guidelines and incorporate a systematic review process. The published literature was searched from relevant electronic databases, including PubMed, Scopus, Cochrane Central Register of Controlled Trials, and Web of Science from database inception to March 29, 2021. Inclusion criteria encompassed studies that described peripheral nerve stimulation in patients in terms of clinical outcomes for various pain conditions, physiological mechanism of action, surgical technique, technique of placement, and adverse events. Twenty randomized controlled trials and 33 prospective observational studies were included in the systematic review process. There is Level I evidence supporting the efficacy of PNS for treatment of chronic migraine headaches via occipital nerve stimulation; chronic hemiplegic shoulder pain via stimulation of nerves innervating the trapezius, supraspinatus, and deltoid muscles; failed back surgery syndrome via subcutaneous peripheral field stimulation; and lower extremity neuropathic and lower extremity post-amputation pain. Evidence from current Level I studies combined with newer technologies facilitating less invasive and easier electrode placement make peripheral nerve stimulation an attractive alternative for managing patients with complex pain disorders. Peripheral nerve stimulation should be used judiciously as an adjunct for chronic and acute postoperative pain following adequate patient screening and positive diagnostic nerve block or stimulation trial.Keywords: post-amputation pain, low back pain, peripheral neuropathy, chronic postoperative pain

BackgroundThe effect of sex and age on chronic post-thoracic surgical pain (CPTP) at rest and with activity remains unclear. The main purpose of this study was to investigate the relationship between the incidence of chronic postoperative pain (at rest and with activity) and sex/age differences.MethodsThis was a single-center retrospective study that included adult patients who had undergone elective thoracic surgery. Patients were divided into two groups based on sex. Demographic and perioperative data were collected, including age, sex, education level, Body Mass Index (BMI), American Society of Anesthesiologists (ASA) physical status, and medical history (hypertension, diabetes mellitus). Chronic postoperative pain data were collected by telephone follow-up.ResultsAmong the 3,159 patients enrolled, 1,762 were male, and 1,397 were female. After creating a matched-pairs cohort, 1,856 patients were analyzed. The incidence of CPTP at rest was 14.9% among males and 17.8% among females (p = 0.090). The incidence of CPTP with activity was 28.4% among males and 35.0% among females (p = 0.002). We analyzed three different models after propensity matching to validate the stability of the prediction model between sex and CPTP, and female sex was a significant predictor of CPTP with activity 3 months after surgery. Further analysis showed that females in the 45-55-year-old age group were more prone to develop CPTP.ConclusionFemales have a higher incidence of chronic postoperative pain with activity after thoracic surgery. Females in the 45-55-year-old age group are more prone to develop CPTP than females in other age groups.

Hysterectomy currently occupies one of the leading places among obstetric and gynecological surgeries and is one of the highly effective and sometimes the only method of treating various diseases of the female genital organs. Quite often, however, hysterectomy results not only in the elimination of the cause of disease, but also in the development of complications that reduce the quality of life of patients. More and more attention is being paid to neurological complications, which is obviously due to improved diagnostic capabilities, as well as the results of recent research on the pathogenesis and treatment of neurological disorders. Only recently the scientists have begun to think about the true causes of one of the most important neurologic complications of hysterectomy, namely chronic postoperative pain.The review describes in detail the main neurological disorders that develop after hysterectomy: chronic postoperative pain, traumatic neuroma, residual ovarian syndrome as possible causes of chronic pain, mononeuropathies, sexual and sleep disorders, decreased cognitive and motor functions, lower urinary tract and bowel dysfunction. Considerable attention is given to the mechanisms of neurological complications and the relationship between the surgery and emotional disturbances in women.

Aim: This study aimed to evaluate the effectiveness of ultrasound-guided transversus abdominis plane (TAP) block in patients diagnosed with chronic pain after undergoing lower abdominal surgery. Methods: Patients who were admitted to the pain medicine clinic between January 1, 2016, and January 1, 2020, and underwent TAP block with the diagnosis of chronic pain after undergoing lower abdominal surgery were retrospectively analyzed. The visual analog scale (VAS) score was measured before the procedure and at the 1-month and 3-month follow-ups. Results: The proportion of patients with a reduction in VAS scores of >50% after TAP block application was 50% at the 1-month follow-up and 72.5% at the 3-month follow-up. The changes in the VAS score was found to be statistically significant (p < 0.05). Conclusion: Although ultrasound-guided TAP block seems to be an effective treatment method for chronic pain after lower abdominal surgery, further studies and clinical trials investigating different types of surgeries and including a larger number of patients are warranted.

Background and Purpose: Chronic postoperative pain (CPSP) after cardiac surgery can cause severe health problems. As demonstrated in noncardiac surgeries, preoperative chronic pain can potentially lead to CPSP. However, the association between preoperative chronic pain and CPSP over follow-up in cardiac surgical settings in the context of sex differences is still lacking. This observational study aims to explore the role and sex differences of preoperative chronic pain in the occurrence and development of long-term CPSP and CPSP-related complications after cardiac surgery. Patients and Methods: This observational study enrolled 495 patients (35.3% women) who underwent cardiac surgery via median sternotomy in March 2019. Validated questionnaires were delivered to assess preoperative chronic pain and moderate to severe CPSP at 3 and 24 months following surgical procedures. The secondary outcomes included the occurrence of moderate to severe chronic pruritus, sleep disturbance, and daily activities interference at follow-up. Multivariable logistic regression was employed. Results: Of 495 patients analyzed, the incidences of preoperative chronic pain (29.7% versus 20.6%) and moderate to severe CPSP (14.8% versus 8.1%) were both higher in females than males. Female sex (P = 0.048) and preoperative chronic pain (P = 0.008) were identified as significant risk factors for CPSP occurrence. However, preoperative chronic pain contributed significantly to CPSP (P = 0.008), sleep disturbance (P =0.047), and daily activities interference (P =0.019) in females, but not in males. Conclusion: The 2-year prevalence of moderate to severe CPSP after cardiac surgery was 10.5%. Compared to males, females are more susceptible to CPSP and pain-related outcomes in the long term. In addition, preoperative chronic pain was associated with a higher risk of CPSP in females but not in males. [ABSTRACT FROM AUTHOR]

Background: Chronic pain is a major complication following breast surgery including breast reconstruction. We previously examined prospective patient-specific and medical/surgical factors that predict chronic pain a year after breast surgery in the Japanese population. Five-year survivorship is essential for breast cancer patients. This report is a 4-year follow-up study following the previous research. Methods: A follow-up observation study was performed 5 years after breast operations. The subjects were patients who underwent breast surgery, including tissue expander/implant (TE/implant), DIEP procedures and mastectomy only. Pain at 5 years was assessed using the Japanese Version of the Short-Form McGill Pain Questionnaire (SF-MPQ-JV). A multiple linear regression model was used to examine the relationships of clinical factors with chronic pain. Results: Questionnaires were completed by 132 subjects. No factor related to chronic pain was significantly related to the MPQ pain ratings. Among patient characteristics, a psychotic or neurological medical history was related to significantly lower visual analog scale (p = 0.02) and present pain index (p = 0.04) scores. A history of chemotherapy and/or hormone therapy was significantly associated with the frequency of use of pain medication postoperatively (p = 0.05) and effect on the social life of the patients (p = 0.02). Conclusions: A psychotic or neurological history and a history of chemotherapy and/or hormone therapy were identified as risk factors for chronic pain after breast surgery, but the type of operation was not associated with chronic pain. [ABSTRACT FROM AUTHOR]

Up to 56% of patients develop chronic postsurgical pain (CPSP) after coronary artery bypass grafting (CABG). CPSP can affect patients' moods and decrease daily activities. The primary aim of this study was to investigate CPSP severity in patients following off-pump (OP) CABG using the Neuropathic Pain Symptom Inventory (NPSI). This was a prospective cohort study conducted in a cardiac surgery department of a teaching hospital. Patients undergoing OP-CABG were enrolled in an erector spinae plane block (ESPB) group (n = 27) or a control (CON) group (n = 24). Before the induction of general anesthesia, ESPB was performed on both sides under ultrasound guidance using 0.375% ropivacaine. The secondary outcomes included cumulative oxycodone consumption, acute pain intensity, mechanical ventilation time, hospital length of stay, and postoperative complications. CPSP intensity was lower in the ESPB group than in the CON group 1, 3, and 6 months post-surgery (p < 0.001). Significant between-group differences were also observed in other outcomes, including postoperative pain severity, opioid consumption, mechanical ventilation time, and hospital length of stay, in favor of the ESPB group. Preemptive ESPB appears to decrease the risk of CPSP development in patients undergoing OP-CABG. Reduced acute pain severity and shorter mechanical ventilation times and hospital stays should improve patients' satisfaction and reduce perioperative complications. [ABSTRACT FROM AUTHOR]

Background: Thoracoscopic radical pneumonectomy is associated with a high incidence of postoperative chronic pain. Studies on the benefits of lidocaine intravenous infusion during the perioperative period were still controversial in thoracoscopic surgery. Methods: Sixty-four lung cancer patients scheduled for thoracoscopic radical pneumonectomy were randomly divided into two groups: normal saline group (control group) or lidocaine group. In the lidocaine group, 1.5 mg/kg lidocaine was administered during the anesthesia induction, and 2 mg·kg−1·h−1 lidocaine was continuously intravenous infused until the end of the surgery. After the surgery, a mixture of 2 μg/kg sufentanil and 10 mg/kg lidocaine was continuously intravenous infused by postoperative patient-controlled intravenous analgesia pump (100 ml). In the control group, the same volume of normal saline was administered according to the calculation of lidocaine during anesthesia induction, maintenance and postoperative patient-controlled intravenous analgesia. The primary outcome was the incidence of chronic postoperative pain at 3 months after the surgery. The secondary outcomes include the incidence of chronic postoperative pain at 6 months after the surgery; the effect of lidocaine on postoperative pain within the first 24 and 48 h; total amount of sufentanil administered during entire procedure and the number of PCA triggers within 48 h after surgery. Results: Compared with the control group, the incidence of chronic pain at 3 months after the surgery was significantly lower (13 cases, 46.4% vs. 6 cases, 20.7%, p < 0.05), but no significant difference at 6 months between two group. The cumulative dosage of sufentanil in perioperative period was significantly lower (149.64 ± 18.20 μg vs. 139.47 ± 16.75 μg) (p < 0.05), and the number of PCA triggers (8.21 ± 4.37 vs. 5.83 ± 4.12, p < 0.05) was significantly greater in the control group. The NRS pain scores at 24 h (1.68 ± 0.72 vs. 1.90 ± 0.86) and 48 h (1.21 ± 0.42 vs. 1.20 ± 0.41) after the operation were no significant difference. Conclusion: Perioperative infusion lidocaine significantly reduced the number of PCA triggers and the incidence of chronic postoperative pain at 3 months after the thoracoscopic radical pneumonectomy. Trial registration: http://www.chictr.org.cn: ChiCTR1900024759, frist registration date 26/07/2019. [ABSTRACT FROM AUTHOR]

To examine whether perioperative thermal quantitative sensory testing could be used to identify patients at high risk of chronic pain after video-assisted thoracoscopic surgery (VATS). A single-center, prospective, observational study. At the Peking University People's Hospital. A total of 111 patients scheduled to undergo VATS were enrolled. Quantitative sensory testing was conducted at the anterior intercostal incision prior to surgery and after chest tube removal. The patient's chronic pain was assessed at 3 months after surgery using a questionnaire. The incidence of chronic pain was 35 out of 107 evaluable patients (32.7%). Among the 35 patients with chronic pain, 26 had features characteristic of neuropathic pain (74.3%). Compared to the patients without chronic pain, subjects with chronic pain had a significantly greater perioperative change in cold pain threshold (CPT; p = 0.032), but not cold detection threshold, warm detection threshold, and hot pain threshold. In the multivariate regression, perioperative CPT change was associated with chronic pain after VATS (odds ratio = 1.043, p = 0.026). Chronic pain after VATS is typically neuropathic. The change in perioperative CPT at the incision site may help to identify patients at higher risk of chronic pain after VATS. [ABSTRACT FROM AUTHOR]

ObjectiveTo review the published evidence regarding perioperative analgesic techniques for breast cancer-related surgery.DesignTopical review.MethodsRandomized, controlled trials (RCTs) were selected for inclusion in the review. Also included were large prospective series providing estimates of potential risks and technical reports and small case series demonstrating a new technique or approaches of interest to clinicians.ResultsA total of 514 abstracts were reviewed, with 284 studies meeting criteria for full review. The evidence regarding preemptive ketamine, scheduled opioids, perioperative non-steroidal anti-inflammatory drugs (NSAIDs), and intravenous lidocaine is mixed and deserves further investigation. There is strong evidence that both pregabalin and gabapentin provide analgesic benefits following breast surgery. There is minimal and conflicting data from high-quality randomized, controlled studies suggesting that directly infiltrating and/or infusing local anesthetic (liposome encapsulated or unencapsulated) into the surgical wound is a reliably effective analgesic. In contrast, there is a plethora of data demonstrating the potent analgesia, opioid sparing, and decreased opioid-related side effects from thoracic epidural infusion and both single-injection and continuous paravertebral nerve blocks (the latter two demonstrating decreased persistent post-surgical pain between 2.5 and 12 months). Techniques with limited-yet promising-data deserving additional investigation include brachial plexus blocks, cervical epidural infusion, interfascial plane blocks, and interpleural blocks.ConclusionsWhile there are currently multiple promising analgesic techniques for surgical procedures of the breast that deserve further study, the only modalities demonstrated to provide potent, consistent perioperative pain control are thoracic epidural infusion and paravertebral nerve blocks.

Introduction: The transition of acute to chronic postoperative pain (CPP) remains a significant burden to the rehabilitation of patients. The research for adjuvants to prevent CPP continues; among others, dexmedetomidine and lidocaine seem promising agents. Methods: This is a long-term follow-up of a randomized, placebo-controlled, double-blind study on women who underwent open abdominal gynecological surgery and received dexmedetomidine or lidocaine or placebo infusion perioperatively (n = 81). The effect of these adjuvants on the development of CPP and neuropathic pain was assessed during a 12-month follow-up. Eighty-one (81) women ASA I–II, aged between 30 and 70 years, were randomly assigned to receive either dexmedetomidine (DEX group) or lidocaine (LIDO group) or placebo (CONTROL group) perioperatively. Before anesthesia induction, all patients received a loading intravenous dose of either 0.6 μg/kg dexmedetomidine or 1.5 mg/kg lidocaine or placebo, followed by 0.6 μg/kg/h dexmedetomidine or 1.5 mg/kg/h lidocaine or placebo until last suture. Patients were followed up to obtain the long-term outcomes at 3, 6, and 12 months. At these time-points, pain intensity was assessed with the Numerical Rating Scale, (NRS: 0–10) and the development of neuropathic elements with the Douleur Neuropathique 4 (DN4) score. Prognostic parameters that could affect chronic pain and its components were also identified. Results: Data from 74 women were analyzed. Dexmedetomidine significantly reduced NRS scores comparing to placebo at 3 months (p = 0.018), while at 6 months, lidocaine was found superior to placebo (p = 0.02), but not to dexmedetomidine, in preventing neuropathic pain (DN4 < 4). Regarding secondary endpoints, higher NRS cough scores at 48 h were associated with statistically significant NRS and DN4 scores at 3, 6, and 12 months (p < 0.02). At 6 months, a statistically significant correlation was also found between higher NRS values and older age (p = 0.020). Conclusions: Dexmedetomidine was superior to placebo regarding the duration and severity of CPP, while lidocaine exhibited a protective effect against neuropathic elements of CPP. Trial registration: ClinicalTrials.gov identifier, NCT03363425. [ABSTRACT FROM AUTHOR]

Background and Objectives: Quality of life (QoL) and chronic pain are important outcomes following hernia surgery. The long-term effects of Transcutaneous Electric Nerve Stimulation (TENS) on postoperative recovery are not well known. In this trial we investigated the role of TENS on QoL and on the incidence of chronic pain following inguinal hernia repair with mesh. Materials and Methods: A total of 80 male patients with elective primary unilateral hernia Lichtenstein repair were randomly allocated to receive TENS or a placebo-TENS procedure. The TENS group received conventional TENS twice a day on the first and second postoperative days. The intensity was set at 0–0.5 mA in the placebo-TENS group. General and hernia-specific QoL, as well as the incidence of chronic pain were assessed using SF-36v2 and the Carolinas comfort scale. Results: Less sensation of mesh was reported by the TENS group patients one week after surgery. At this time point, the mean sensation score was 6.07 ± 8.88 in the TENS group and 14.08 ± 16.67 in the placebo-TENS group (p = 0.029). Although at two days and one week postoperatively, TENS group patients tended to have less pain, less movement restrictions and better overall hernia-specific QoL, the differences were not statistically significant. At 6 months postoperatively, no incidence of chronic pain was found in either the placebo-TENS or TENS group. Conclusions: Conventional TENS applied in the early postoperative period following inguinal hernia repair with mesh was found to reduce mesh-related foreign body sensation one week after surgery. Promising results were also found for other QoL domains. [ABSTRACT FROM AUTHOR]

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The ubiquitous application of inguinal hernioplasty performed by various methods does not exclude the occurrence of certain late postoperative complications, the cause of which is sometimes extremely difficult to establish. The article describes a clinical case of observing a patient with chronic postoperative pain 6 months after inguinal hernioplasty using the TAPP technique. When studying the possible causes, the presence of a fixing material (tacker) in the triangle of pain was found, the removal of the latter led to a complete leveling of the clinical picture. Thus, despite the simplicity of performing inguinal hernioplasty, the surgeons desire for excessive fixation and a violation of the principles of this operation can lead to undesirable complications and temporary disability of the patient.

Summary: 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 (1.5 mg.kg‐1) and infusion (2 mg.kg‐1.h‐1) intra‐operatively, and a subcutaneous infusion (1.33 mg.kg‐1.h‐1) postoperatively for up to 12 h 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 6 months. The adjusted odds ratio (95%CI) for postoperative pain at 6 months 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. [ABSTRACT FROM AUTHOR]

The objective of our clinical study was to identify the relationship between the incidence of persistent pain in the late postoperative period and polymorphisms (SNP) in the COMT and GCH1 genes.Subjects and methods. Following the provision of written informed consent, 102 patients (57 women and 45 men) with ASA physical condition I/II underwent transabdominal radical prostatectomy (n = 45) or hysterectomy (n = 57) for cancer-related pathology. The frequency and intensity of postoperative residual pain in the pelvic and scar areas were assessed by a nurse in all patients using a telephone survey three months after discharge from the clinic. Genotyping was performed in the region Chr14q22.1 and 22q11.21 containing the genes GCH1 and COMT, respectively. We identified five SNP GCH1s that, as shown, had a significant association with pain reactions in a previous study by Tegeder and co-authors: rs752688, rs4411417, rs8007201, rs3783641 and rs8007267, and one SNP COMT-rs4680 G1947A.Results and discussion. In the first three months after discharge from the hospital, 35 patients (34.3%) were diagnosed with moderate and severe pain of varying duration. In this group, 6 (17.1%) patients manifested signs of chronic neuropathic pain. Statistical analysis of 102 patients undergoing surgery on the lower floor of the abdominal cavity showed a statistically significant relationship only between GCH1 rs752688 and the more frequent occurrence of chronic postoperative pain. This relationship was mainly found in the male patient group, which indicated a gender-dependent effect. SNP GCH1rs752688 can be used as a clinical "marker" of chronic pain.

Chronic postsurgical pain (CPSP) is a common complication after surgery; however, the underlying mechanisms of CPSP are poorly understood. As one of the most important inflammatory pathways, the Toll‐like receptor 4/nuclear factor‐kappa B (TLR4/NF‐κB) signaling pathway plays an important role in chronic pain. However, the precise role of the TLR4/NF‐κB signaling pathway in CPSP remains unclear. In the present study, we established a rat model of CPSP induced by skin/muscle incision and retraction (SMIR) and verified the effects and mechanisms of central and peripheral TLR4 and NF‐κB on hyperalgesia in SMIR rats. The results showed that TLR4 expression was increased in both the spinal dorsal horn and dorsal root ganglia (DRGs) of SMIR rats. However, the TLR4 expression pattern in the spinal cord was different from that in DRGs. In the spinal cord, TLR4 was expressed in both neurons and microglia, whereas it was expressed in neurons but not in satellite glial cells in DRGs. Further results demonstrate that the central and peripheral TLR4/NF‐κB signaling pathway is involved in the SMIR‐induced CPSP by different mechanisms. In the peripheral nervous system, we revealed that the TLR4/NF‐κB signaling pathway induced upregulation of voltage‐gated sodium channel 1.7 (Nav1.7) in DRGs, triggering peripheral hyperalgesia in SMIR‐induced CPSP. In the central nervous system, the TLR4/NF‐κB signaling pathway participated in SMIR‐induced CPSP by activating microglia in the spinal cord. Ultimately, our findings demonstrated that activation of the peripheral and central TLR4/NF‐κB signaling pathway involved in the development of SMIR‐induced CPSP. [ABSTRACT FROM AUTHOR]

Background and Objectives: Quality of life (QoL) and chronic pain are important outcomes following hernia surgery. The long-term effects of Transcutaneous Electric Nerve Stimulation (TENS) on postoperative recovery are not well known. In this trial we investigated the role of TENS on QoL and on the incidence of chronic pain following inguinal hernia repair with mesh. Materials and Methods: A total of 80 male patients with elective primary unilateral hernia Lichtenstein repair were randomly allocated to receive TENS or a placebo-TENS procedure. The TENS group received conventional TENS twice a day on the first and second postoperative days. The intensity was set at 0–0.5 mA in the placebo-TENS group. General and hernia-specific QoL, as well as the incidence of chronic pain were assessed using SF-36v2 and the Carolinas comfort scale. Results: Less sensation of mesh was reported by the TENS group patients one week after surgery. At this time point, the mean sensation score was 6.07 ± 8.88 in the TENS group and 14.08 ± 16.67 in the placebo-TENS group (p = 0.029). Although at two days and one week postoperatively, TENS group patients tended to have less pain, less movement restrictions and better overall hernia-specific QoL, the differences were not statistically significant. At 6 months postoperatively, no incidence of chronic pain was found in either the placebo-TENS or TENS group. Conclusions: Conventional TENS applied in the early postoperative period following inguinal hernia repair with mesh was found to reduce mesh-related foreign body sensation one week after surgery. Promising results were also found for other QoL domains.

Purpose: The aim of this study was to identify preoperative predictors for 1-year posttotal knee arthroplasty (TKA) pain and pre- to post-TKA pain difference in knee osteoarthritis (KOA) patients., Methods: From March 2018 to July 2023, this prospective longitudinal cohort study enrolled KOA patients awaiting TKA from four hospitals in Belgium and the Netherlands. Different biopsychosocial predictors were assessed preoperatively by questionnaires and physical examinations (input variables). The Knee injury and Osteoarthritis Outcome Score (KOOS) subscale pain was used to measure pain intensity. The absolute KOOS subscale pain score 1-year post-TKA and the difference score (ΔKOOS = 1-year postoperative - preoperative) were used as primary outcome measures (output variables). Two multivariable linear regression analyses were performed., Results: Two hundred and twenty-three participants were included after multiple imputation. Worse absolute KOOS subscale pain scores 1-year post-TKA and negative or closer to zero ΔKOOS subscale pain scores were predicted by self-reported central sensitisation, lower KOA grade and preoperative satisfaction, and higher glycated haemoglobin, number of pain locations and personal control (adjusted R 2  = 0.25). Additional predictors of negative or closer to zero ΔKOOS subscale pain scores were being self-employed, higher preoperative pain and function (adjusted R 2  = 0.37)., Conclusion: This study reports different biopsychosocial predictors for both outcomes that have filtered out other potential predictors and provide value for future studies on developing risk assessment tools for the prediction of chronic TKA pain., Protocol Registration: The protocol is registered at clinicaltrials.gov (NCT05380648) on 13 May 2022., Level of Evidence: Level II., (© 2024 The Authors. Knee Surgery, Sports Traumatology, Arthroscopy published by John Wiley & Sons Ltd on behalf of European Society of Sports Traumatology, Knee Surgery and Arthroscopy.)

Morten Rune Blichfeldt-Eckhardt,1,2 Claus Andersen,2 Helle Ørding,1 Peter B Licht,3 Palle Toft2 1Department of Anesthesiology, Vejle Hospital, Vejle, Denmark; 2Department of Anesthesiology and Intensive Care, Odense University Hospital, Odense, Denmark; 3Department of Thoracic Surgery, Odense University Hospital, Odense, Denmark Purpose: Acute postoperative pain is a strong predictor for postthoracotomy pain syndrome (PTPS), but the mechanism is unknown. Even though thoracic pain is usually considered the dominating acute pain after thoracic surgery, up to 45% of patients consider shoulder pain to be dominating pain and often this shoulder pain is referred visceral pain. This study aims to examine which components of the acute pain response after thoracic surgery were associated with PTPS and if any signs of a generalized central hypersensitivity could be identified in patients with PTPS.Patients and methods: In a prospective cohort study, 60 consecutive patients for lobectomy were included and examined preoperatively and 12 months postoperatively for pain and signs of hypersensitivity using a comprehensive protocol for quantitative sensory testing. Thoracic pain, shoulder pain, referred pain, and overall pain were assessed five times daily during the first four postoperative days.Results: Sixteen patients (31% of the 52 patients who completed the study) developed PTPS. Thoracic pain was the only pain component that was associated with PTPS and was a stronger predictor for PTPS than overall pain. There were no signs of hypersensitivity before or after the operation in patients with PTPS, but patients with PTPS more often suffered from preoperative pain.Conclusion: Thoracic pain was the only component of the acute pain response that predicted PTPS and was a stronger predictor than overall pain. Keywords: postthoracotomy pain syndrome, acute postoperative pain, chronic postoperative pain, referred pain, thoracic surgery

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. [ABSTRACT FROM AUTHOR]

Effective prevention of chronic postoperative pain is an important clinical goal, informed by a growing body of studies. Peri-operative regional anaesthesia remains one of the most important tools in the multimodal analgesic toolbox, blocking injury-induced activation and sensitisation of both the peripheral and central nervous system. We review the definition and taxonomy of chronic postoperative pain, its mechanistic basis and the most recent evidence for the preventative potential of multimodal analgesia, with a special focus on regional anaesthesia. While regional anaesthesia targets several important aspects of the mechanistic pathway leading to chronic postoperative pain, evidence for its efficacy is still mixed, possibly owing to the heterogeneity of risk profiles within the surgical patient, but also to variation in techniques and medications reported in the literature. [ABSTRACT FROM AUTHOR]

The article highlights and discusses several current topics that have been published in the field of acute pain therapy last year. It summarizes the current publications concerning systemic analgesia, organisation of pain therapy and international guidelines concerning acute pain therapy. [ABSTRACT FROM AUTHOR]