Transition from acute to chronic pain after surgery

Beyond the Surgery: The Impact of Coping Strategies on Persistent Pain After Rotator Cuff Repair

Background: Rotator cuff repair is widely recognized as one of the most painful orthopedic surgeries, yet postoperative pain management in these patients is often underexplored. This study aimed to explore the relationship between pain outcomes and functional recovery six months after arthroscopic rotator cuff repair (ARCR), with a focus on the role of different pain coping mechanisms as mediators. Methods: This study included 83 patients that underwent rotator cuff repair. Pain levels were assessed using the Brief Pain Inventory (BPI-SF), while shoulder function was evaluated using the Oxford Shoulder Score (OSS). Coping strategies, including self-statements, ignoring pain, distraction, and praying, were examined in relation to pain severity and interference and were assessed with the Coping Strategies Questionnaire-Revised (CSQ-R). Simple and parallel mediation analyses were performed using the PROCESS macro to assess the mediating effects of coping mechanisms on the relationship between pain intensity, pain interference, and postoperative OSS. Results: Post-surgery, patients showed a significant improvement in OSS (from 29 ± 9 to 42 ± 6). At six months, 24% of patients reported chronic postsurgical pain (CPSP), defined as a pain severity score of 3 or higher. Correlation analyses revealed that OSS was negatively associated with pain catastrophizing (r = -0.35, p < 0.01) and praying (r = -0.28, p < 0.01). OSS was significantly negatively associated with pain severity (r = -0.54; p < 0.01) and pain interference (r = -0.51, p < 0.01). Mediation analysis demonstrated that coping self-statements significantly mediated the relationship between pain interference and shoulder function (a*b = 0.5266 (BootSE = 0.2691, 95% CI [0.1010, 1.1470]), emphasizing the important role of cognitive strategies in supporting recovery outcomes. Conclusion: Patients engaging in adaptive coping strategies, particularly coping self-statements, reported better functional outcomes. The findings underscore the importance of targeted interventions focusing on effective pain coping mechanisms to improve recovery post-ARCR.

Current concepts and targets for preventing the transition of acute to chronic postsurgical pain

PURPOSE OF REVIEW

It is estimated that approximately a third of patients undergoing certain surgeries may report some degree of persistent pain postoperatively. Chronic postsurgical pain (CPSP) reduces quality of life, is challenging to treat, and has significant socio-economic impact.

RECENT FINDINGS

From an epidemiological perspective, factors that predispose patients to the development of CPSP may be considered in relation to the patient, the procedure or, the care environment. Prevention or management of transition from acute to chronic pain often need a multidisciplinary approach beginning early in the preoperative period and continuing beyond surgical admission. The current concepts regarding the role of central and peripheral nervous systems in chronification of pain may provide targets for future therapies but, the current evidence seems to suggest that a multimodal analgesic approach of preventive analgesia along with a continued follow-up and treatment after hospital discharge may hold the key to identify and manage the transitioning of acute to chronic pain.

SUMMARY

A comprehensive multidisciplinary approach with prior identification of risk factors, minimizing the surgical insult and a culture of utilizing multimodal analgesia and continued surveillance beyond the period of hospitalization is an important step towards reducing the development of chronic pain. A transitional pain service model may accomplish many of these goals.

Risk factors for persistent postoperative opioid use: an entity distinct from chronic postsurgical pain

Despite a decline in opioid prescriptions over the past decade, patients commonly receive opioid analgesics as a treatment for postoperative pain in the USA. One complication that patients may experience after surgery is persistent postoperative opioid use (PPOU), or opioid use beyond the typical recovery period. Often defined as beyond 3 months postsurgery, PPOU is frequently conflated with chronic postsurgical pain (CPSP), where pain persists well after the expected healing time following surgery. This narrative review explores the distinct risk factors for each condition, their interrelation, and potential future research directions.For PPOU, major risk factors include the risky use of substances including misuse and use disorders; depression and other mental health disorders; a history of chronic pain before surgery including back pain; and certain surgical types (ie, total knee arthropathy, open cholecystectomy, total hip arthropathy). Conversely, CPSP risk factors include the type of surgery (ie, thoracic and breast surgeries), mental health conditions (particularly catastrophizing), and pain in both the preoperative and postoperative phases. Despite the overlap of some factors, studies typically employ different frameworks when examining PPOU and CPSP, with a biopsychosocial model applied for CPSP and little emphasis on an individual's social environment employed for PPOU. Additionally, existing studies predominantly rely on retrospective insurance claims data, which may not capture the full scope of risk factors.To fill gaps in understanding, investigations may prospectively assess and analyze patient-reported outcomes, implement similar frameworks, and concurrently measure both conditions to advance the scientific understanding of PPOU and CPSP.

Persistent pain after total temporomandibular joint replacement surgery: clinical characteristics, comorbidities, and risk factors

Chronic post-surgical pain (CPSP) after temporomandibular joint (TMJ) surgery is an under-recognized problem. The aim of this study was to document the characteristics of CPSP and identify patient risk factors and comorbidities associated with the development of CPSP after total TMJ replacement (TJR). This was a retrospective cohort study of patients who underwent TJR between 2000 and 2018 at Massachusetts General Hospital, Boston, USA. The primary outcome was the presence of CPSP and use of pain medications after TJR. The secondary outcome was the risk factors associated with the development of CPSP. A total 88 patients were included (79 females, 9 males). The mean follow-up was 4.2 years. Overall, 68 (77.3%) had CPSP and 20 (22.7%) had no CPSP. Of those with CPSP, 32.4% had severe pain and 45.6% continued to take pain medications. Of the 27 patients with data available on the characteristics of the pain, the majority had myofascial pain, while some developed neuropathic pain. A significant difference was noted between the CPSP and non-CPSP groups in terms of preoperative pain, smoking behavior, and use of opioids, non-steroidal anti-inflammatory drugs, muscle relaxants, and neuropathic pain medications.

Prevalence of neuropathic pain in patients with symptomatic endometriosis: Assessment using the DN4 score

The mechanisms underlying pain in cases of endometriosis or chronic pelvic pain are complex, often involving various types of pain; mainly nociceptive pain, central sensitization, and neuropathic pain. Our main objective was to examine the prevalence of neuropathic pain in women with symptomatic endometriosis, and secondary, to explore the factors associated with this type of pain and to assess the prevalence of a positive PPSC score and a history of sexual violence within this population. This study is a retrospective, comparative, single-center cohort study conducted from September 2019 to January 2023. The presence of neuropathic pain was confirmed by a positive DN4 score, defined as greater than or equal to 4. The association with the following variables was studied: age, BMI, marital status, smoking, alcohol and drugs consumption, age at menarche, gestity, parity, duration of exposure to endometriosis, MRI locations, laparoscopy for endometriosis and post-laparoscopy r-ASRM classification, hormone treatment, associated symptoms, VAS, associated pathologies, infertility consultation, Pain Center consultation, EPH-5 score, positive PPSC score (≥5), and history of sexual violence. The prevalence of neuropathic pain was 44.1%. Younger age, being in a relationship, having a high EPH-5 score and undergoing laparoscopy for endometriosis are associated with neuropathic pain independently of other variables. Our study underscores the persistent high prevalence of neuropathic pain in endometriosis cases, emphasizing the importance of actively screening for it. Identifying neuropathic pain could prompt referrals to pain specialists, integrating it into a comprehensive multidisciplinary approach.

Chronic Pain Following Breast Reconstruction: A Scoping Review

BACKGROUND

Breast cancer survival rates have increased significantly, underscoring the importance of enhancing long-term health-related quality of life. Breast reconstruction following mastectomy has emerged as a common approach that contributes to improved health-related quality of life. Nonetheless, chronic pain following breast reconstruction is a prevalent issue that has a negative impact on overall well-being.

METHODS

To examine recent findings on chronic pain after breast reconstruction and progress in pain management, we performed a review of the literature through independent searches using the MEDLINE database within NIH National Library of Medicine PubMed.

RESULTS

The review suggested that autologous reconstruction causes chronic postsurgical pain, especially at specific donor sites, whereas implant-based reconstruction does not seem to increase the risk of chronic pain. Moreover, certain operational and patient factors are also associated with chronic pain. Appropriate pain management can reduce chronic pain and prevent the transition from acute to chronic pain.

CONCLUSION

This scoping review evaluated the characteristics of long-term chronic pain after breast reconstruction. The findings provide patients with important treatment information and will assist with their decision on their preferred treatment.

Efficacy of azasetron on postoperative chronic pain after pulmonary surgery: a randomized triple-blind controlled trial

BACKGROUND

Inhibition of 5-HT3 (5-Hydroxyl Tryptamine) receptors is known to enhance morphine analgesia in animal models. We tested the efficacy of azasetron, a 5-HT3 receptor antagonist, on postoperative chronic pain after pulmonary surgery in a randomized triple-blind controlled study.

METHODS

A total of 250 patients who were scheduled to receive pulmonary surgery were randomized to patient-controlled analgesia (PCA) using 200 µg sufentanil with normal saline or 200 µg sufentanil with 20 mg azasetron. The numerical rating scale of pain (NRS) was recorded at baseline, postoperative day (POD) 1, 2, 3, 90, and 180. Negative binomial regression was used to identify associated factors for postoperative NRS six months after surgery.

RESULTS

The results showed that azasetron did not affect the primary outcomes: the incidence of postoperative chronic pain on POD90 and 180. However, azasetron decreased postoperative NRS at rest and activity on POD1, 2, and 3. Furthermore, azasetron decreased postoperative nausea and vomiting on POD1 and 2. Univariate and multivariate negative binomial regression analysis identified preoperative pain, smoking, drinking and open surgery are risk factors of chronic pain six months after surgery.

CONCLUSIONS

Azasetron did not affect the incidence of chronic pain after pulmonary surgery. The presence of preoperative pain, smoking, drinking, and open surgery were found to be associated with chronic pain six months after surgery.

CLINICAL TRIAL REGISTRATION

The trial was registered prior to patient enrollment at the Chinese Clinical Trial Registry (ChiCTR2200060139), 20/05/2022; the site url is https://www.chictr.org.cn/ .

Effects of intravenous lidocaine on postoperative pain and gastrointestinal function recovery following gastrointestinal surgery: a meta-analysis

INTRODUCTION

The full extent of intravenous lidocaine's effectiveness in alleviating postoperative pain and enhancing gastrointestinal function recovery remains uncertain.

EVIDENCE ACQUISITION

We conducted an exhaustive search of databases to identify randomized controlled trials that compared intravenous lidocaine infusion's efficacy to that of a placebo or routine care in patients undergoing gastrointestinal surgery. The primary outcome measure was resting pain scores 24 h postoperatively. We utilized a random-effects model based on the intention-to-treat principle for the overall results.

EVIDENCE SYNTHESIS

This study included twenty-four trials with 1533 patients. Intravenous lidocaine significantly reduced resting pain scores 24 h after gastrointestinal surgery (twenty trials, SMD -0.67, 95% CI -1.09 to -0.24, P=0.002, I2 = 90%). This finding was consistent in subgroup analyses and sensitivity analyses. The benefit was also observed at other resting and moving time points (1, 2, 4, and 12 h) postoperatively. Intravenous lidocaine significantly decreased opioid consumption within 24 h after surgery (eleven trials, SMD: -1.19; 95% CI: -1.99 to -0.39; P=0.003). Intravenous lidocaine also shortened the time to bowel sound (MD: -8.51; 95% CI: -14.59 to -2.44; P=0.006), time to first flatus (MD: -6.00; 95% CI: -9.87 to -2.13; P=0.002), and time to first defecation (MD: -9.77; 95% CI: -17.19 to -2.36; P=0.01).

CONCLUSIONS

Perioperative intravenous lidocaine can alleviate acute pain and expedite gastrointestinal function recovery in patients undergoing gastrointestinal surgery. However, the results should be interpreted with caution due to substantial heterogeneity. Further large-scale studies are necessary to validate these findings.

Time-Dependent Prediction Models for Individual Prognosis of Chronic Postsurgical Pain following Knee Replacement Based on an Extensive Multivariable Data Set

(1) Background: Clinically useful prediction models for chronic postsurgical pain (CPSP) in knee replacement (TKA) are lacking. (2) Methods: In our prospective, multicenter study, a wide-ranging set of 91 variables was collected from 933 TKA patients at eight time points up to one year after surgery. Based on this extensive data pool, simple and complex prediction models were calculated for the preoperative time point and for 6 months after surgery, using least absolute shrinkage and selection operator (LASSO) 1se and LASSO min, respectively. (3) Results: Using preoperative data only, LASSO 1se selected age, the Revised Life Orientation Test on pessimism, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)-subscore pain and the Timed "Up and Go" Test for prediction, resulting in an area under the curve (AUC) of 0.617 and a Brier score of 0.201, expressing low predictive power only. Using data up to 6 months after surgery, LASSO 1se included preoperative Patient Health Questionnaire-4, Knee Injury and Osteoarthritis Outcome Score (KOOS)-subscore pain (pain) 3 months after surgery (month), WOMAC pain 3 and 6 months, KOOS subscore symptoms 6 months, KOOS subscore sport 6 months and KOOS subscore Quality of Life 6 months. This improved the predictive power to an intermediate one (AUC 0.755, Brier score 0.168). More complex models computed using LASSO min did little to further improve the strength of prediction. (4) Conclusions: Even using multiple variables and complex calculation methods, the possibility of individual prediction of CPSP after TKA remains limited.

Pain during the first year after scoliosis surgery in adolescents, an exploratory, prospective cohort study

Objective

Approximately 50% of adolescents who have undergone scoliosis surgery still experience severe pain one year postoperatively. We explored the postoperative pain trajectory and the potential value of preoperative Thermal Quantitative Sensory Testing (T-QST) as predictor of chronic postsurgical pain after scoliosis surgery.

Design

Single-center prospective cohort study in adolescents undergoing scoliosis surgery.

Outcomes

Prevalence of chronic postsurgical pain (CPSP) one year after scoliosis surgery and postsurgical pain course during this year. The need for rescue medication and the relationship between pre-operative T-QST, acute pain and CPSP.

Results

Thirty-nine patients (mean age 13.9 years; SD 1.9 years) completed the study. One year postoperatively, ten patients (26%) self-reported pain [numeric rating scale (NRS) score ≥ 4]) when moving and two (5%) when in rest. Four of these patients (10.3%) experienced neuropathic pain. The pre-operative cold pain threshold was lower (p = 0.002) in patients with CPSP at 12 months. Preoperative cold and heat pain thresholds were correlated with the number of moderate or severe pain reports (NRS ≥ 4) in the first week postoperatively (r -.426; p = 0.009 and r.392; p = 0.016, respectively).

Conclusions

One year after scoliosis surgery, a significant part of patients (26%) still reported pain, some with neuropathic characteristics. Better diagnosis and treatment is needed; our study suggests that T-QST could be further explored to better understand and treat children with this negative outcome.

Chronic post-surgical pain after knee arthroplasty: a role of peripheral nerve blocks

Introduction

Peripheral nerve blocks are an efficient method of pain control after total knee arthroplasty (TKA), but there is no report of their impact on chronic post-surgical pain (CPSP).

Methods

This prospective observational study aimed to assess adductor canal block (ACB) and IPACK block (blocks vs. no blocks) on opioid consumption, postoperative pain score, chronic post-surgical pain 2 years after TKA.

Results

166 patients (82 vs. 84) were analyzed. Opioid consumption was less in the group with blocks (9.74 ± 3.87 mg vs. 30.63 ± 11.52 mg) (p < 0.001). CPSP was present in 20.24% of patients in the group without blocks and 6.1% of patients with blocks (p = 0.011). Predictor variables of CPSP included pain before surgery (cut-off of 5.5), pain at rest (cut-off of 2.35), pain during active movement (cut-off: 2.5), and opioid consumption (cut-off: 8 mg).

Conclusion

Peripheral nerve blocks provide adequate analgesia, significantly decrease opioid consumption, improve functional outcomes, and reduce CPSP 2 years after surgery.

Influences of Cognitive Function and Depressive Symptoms on Pain Trajectories During the First Year Following Hip Fracture Surgery: A Prospective Cohort Study

OBJECTIVES

The purposes of this study were to explore trajectories for patterns of postoperative pain intensity during the first year following hip fracture surgery and the relationships between pain trajectory groups, cognitive impairment, and depressive symptoms.

DESIGN

A prospective cohort correlational study.

SETTING AND PARTICIPANTS

A total of 325 patients aged 60 years or older who had received hip fracture surgery at a 3000-bed medical center in northern Taiwan from September 2012 to March 2020.

METHODS

Data were collected before hospital discharge and at 1, 3, 6, and 12 months postdischarge. Pain intensity was measured using a numeric rating scale; cognitive function was measured with the Taiwan version of the Mini-Mental State Examination; and depressive symptoms were measured by the Geriatric Depression Scale-Short Form. Patients with similar postoperative pain trajectories were categorized into groups and compared with group-based trajectory modeling. Cognitive impairment and depressive symptoms associated with each group were identified by logistic regression.

RESULTS

Three different pain trajectory groups were identified: drastic decline-minimum pain (47.7%), gentle decline-mild pain (45.5%), and slight decline-moderate pain (6.8%). Patients with cognitive impairment [odds ratio (OR) 11.01, 95% CI 2.99-10.51] and at risk for depression (OR 49.09, 95% CI 10.46-230.30) were more likely to be in the moderate pain group than the minimum pain group. Patients with cognitive impairment (OR 2.07, 95% CI 1.25-3.42) were more likely to be in the mild pain group than the minimum pain group. Patients at risk for depression (OR 9.68, 95% CI 3.16-29.63) were more likely to be in the moderate pain group than the mild pain group.

CONCLUSIONS AND IMPLICATIONS

Identifying postoperative pain trajectories can provide insight into the most appropriate pain management for older persons following hip fracture surgery. Attention should focus on assessments for cognitive impairment and risk of depression to prevent persistent postoperative pain. Future studies of older patients with clinically diagnosed cognitive impairment and depression are suggested.

Mechanisms inherent in acute-to-chronic pain after surgery - risk, diagnostic, predictive, and prognostic factors

PURPOSE OF REVIEW

Pain is an expected consequence of a surgery, but it is far from being well controlled. One major complication of acute pain is its risk of persistency beyond healing. This so-called chronic post-surgical pain (CPSP) is defined as new or increased pain due to surgery that lasts for at least 3 months after surgery. CPSP is frequent, underlies a complex bio-psycho-social process and constitutes an important socioeconomic challenge with significant impact on patients' quality of life. Its importance has been recognized by its inclusion in the eleventh version of the ICD (International Classification of Diseases).

RECENT FINDINGS

Evidence for most pharmacological and non-pharmacological interventions preventing CPSP is inconsistent. Identification of associated patient-related factors, such as psychosocial aspects, comorbidities, surgical factors, pain trajectories, or biomarkers may allow stratification and selection of treatment options based on underlying individual mechanisms. Consequently, the identification of patients at risk and implementation of individually tailored, preventive, multimodal treatment to reduce the risk of transition from acute to chronic pain is facilitated.

SUMMARY

This review will give an update on current knowledge on mechanism-based risk, prognostic and predictive factors for CPSP in adults, and preventive and therapeutic approaches, and how to use them for patient stratification in the future.

Construction and Validation of Machine Learning Algorithms to Predict Chronic Post-Surgical Pain Among Patients Undergoing Total Knee Arthroplasty

BACKGROUND

Chronic post-surgical pain (CPSP) is a common but undertreated condition with a high prevalence among patients undergoing total knee arthroplasty (TKA). An effective model for CPSP prediction has not been established yet.

AIMS

To construct and validate machine learning models for the early prediction of CPSP among patients undergoing TKA.

DESIGN

A prospective cohort study.

PARTICIPANTS/SUBJECTS

A total of 320 patients in the modeling group and 150 patients in the validation group were recruited from two independent hospitals between December 2021 and July 2022. They were followed up for 6 months to determine the outcomes of CPSP through telephone interviews.

METHODS

Four machine learning algorithms were developed through 10-fold cross-validation for five times. In the validation group, the discrimination and calibration of the machine learning algorithms were compared by the logistic regression model. The importance of the variables in the best model identified was ranked.

RESULTS

The incidence of CPSP in the modeling group was 25.3%, and that in the validation group was 27.6%. Compared with other models, the random forest model achieved the best performance with the highest C-statistic of 0.897 and the lowest Brier score of 0.119 in the validation group. The top three important factors for predicting CPSP were knee joint function, fear of movement, and pain at rest in the baseline.

CONCLUSIONS

The random forest model demonstrated good discrimination and calibration capacity for identifying patients undergoing TKA at high risk for CPSP. Clinical nurses would screen out high-risk patients for CPSP by using the risk factors identified in the random forest model, and efficiently distribute preventive strategy.

Prognostic models for chronic postsurgical pain-Current developments, trends, and challenges

PURPOSE OF REVIEW

Prognostic models for chronic postsurgical pain (CPSP) aim to predict the likelihood for development and severity of CPSP in individual patients undergoing surgical procedures. Such models might provide valuable information for healthcare providers, allowing them to identify patients at higher risk and implement targeted interventions to prevent or manage CPSP effectively. This review discusses the latest developments of prognostic models for CPSP, their challenges, limitations, and future directions.

RECENT FINDINGS

Numerous studies have been conducted aiming to develop prognostic models for CPSP using various perioperative factors. These include patient-related factors like demographic variables, preexisting pain conditions, psychosocial aspects, procedure-specific characteristics, perioperative analgesic strategies, postoperative complications and, as indicated most recently, biomarkers. Model generation, however, varies and performance and accuracy differ between prognostic models for several reasons and validation of models is rather scarce.

SUMMARY

Precise methodology of prognostic model development needs advancements in the field of CPSP. Development of more accurate, validated and refined models in large-scale cohorts is needed to improve reliability and applicability in clinical practice and validation studies are necessary to further refine and improve the performance of prognostic models for CPSP.

The mechanisms and management of persistent postsurgical pain

An estimated 10%-50% of patients undergoing a surgical intervention will develop persistent postsurgical pain (PPP) lasting more than 3 months despite adequate acute pain management and the availability of minimally invasive procedures. The link between early and late pain outcomes for surgical procedures remains unclear-some patients improve while others develop persistent pain. The elective nature of a surgical procedure offers a unique opportunity for prophylactic or early intervention to prevent the development of PPP and improve our understanding of its associated risk factors, such as pre-operative anxiety and the duration of severe acute postoperative pain. Current perioperative pain management strategies often include opioids, but long-term consumption can lead to tolerance, addiction, opioid-induced hyperalgesia, and death. Pre-clinical models provide the opportunity to dissect mechanisms underpinning the transition from acute to chronic, or persistent, postsurgical pain. This review highlights putative mechanisms of PPP, including sensitisation of peripheral sensory neurons, neuroplasticity in the central nervous system and nociceptive signalling along the neuro-immune axis.

Intravenous Methadone for Perioperative and Chronic Cancer Pain: A Review of the Literature

Intravenous methadone may be useful in acute and chronic pain management compared with other opioids because of its pharmacokinetic and pharmacodynamic characteristics, including the long duration of effect and ability to modulate both pain stimuli propagation and analgesic descending pathways. However, methadone is underused in pain medicine because of several misperceptions. A review of studies was performed to assess data regarding the use of methadone in perioperative pain and chronic cancer pain. The majority of studies have shown that intravenous methadone produces an effective postoperative analgesia and lowers opioid consumption in the postoperative period, without more adverse effects in comparison with other opioid analgesics, and has an interesting potential to prevent persistent postoperative pain. A minority of studies investigated the use of intravenous methadone for cancer pain management. These studies were mostly case series that showed promising activities of intravenous methadone for difficult pain conditions. There is sufficient evidence suggesting that intravenous methadone is effective in perioperative pain, while more studies are needed in patients with cancer pain.

Transitional Pain Medicine; New Era, New Opportunities, and New Journey

Chronic postsurgical pain (CPSP), also known as persistent postsurgical pain (PPSP), is pain that develops or increases in intensity after a surgical procedure and lasts more than 3 months. Transitional pain medicine is the medical field that focuses on understanding the mechanisms of CPSP and defining risk factors and developing preventive treatments. Unfortunately, one significant challenge is the risk of developing opioid use dependence. Multiple risk factors have been discovered, with the most common, and modifiable, being uncontrolled acute postoperative pain; preoperative anxiety and depression; and preoperative site pain, chronic pain, and opioid use.

Unresolved early post-operative pain trajectory predicts moderate-to-severe persistent pain after breast cancer surgery-An observational cohort study

BACKGROUND

Modelling acute post-operative pain trajectories may improve the prediction of persistent pain after breast cancer surgery (PPBCS). This study aimed to investigate the predictive accuracy of early post-operative pain (EPOP) trajectories in the development of PPBCS.

MATERIALS & METHODS

This observational study was conducted in a French Comprehensive Cancer Centre and included patients who underwent breast cancer surgery from December 2017 to November 2018. Perioperative and follow-up data were obtained from medical records, and anaesthesia and perioperative charts. EPOP was defined as pain intensity during the first 24 h after surgery, and modelled by a pain trajectory. K-means clustering method was used to identify patient subgroups with similar EPOP trajectories. The prevalence of moderate-to-severe PPBCS (numeric rating scale ≥4) was evaluated until 24 months after surgery.

RESULTS

A total of 608 patients were included in the study, of which 18% (n = 108) and 9% (n = 52) reported mild and moderate-to-severe PPBCS, respectively. Based on EPOP trajectories, we were able to identify a low (64%, n = 388), resolved (30%, n = 182), and unresolved (6%, n = 38) pain group. Multivariate analysis identified younger age, axillary lymph node dissection, and unresolved EPOP trajectory as independent risk factors for moderate-to-severe PPBCS development. When compared to patients reporting mild PPBCS, moderate-to-severe PPBCS patients experienced significantly more neuropathic pain features, pain-related interference, and delayed opioid cessation.

CONCLUSION

EPOP trajectories can distinguish between resolved and unresolved acute pain after breast cancer surgery, allowing early identification of patients at risk to develop significant PPBCS.

Postoperative Analgesia Management Evaluation in the Postanesthesia Unit: An Exploratory Analysis Based on Patient and Surgery Characteristics

PURPOSE

Several methods have been proposed for postoperative pain management, including administration of opioid analgesics, epidural analgesia, and perineural and infiltrative techniques; however, data are lacking on the relationship between pain intensity, patients' age and gender, and surgery duration.

DESIGN

Prospective, observational, single-center study.

METHODS

The study included patients greater than or equal to 18 years old who underwent surgery with different anesthesia types, grouped according to the American Society of Anesthesiologists' physical status classification score. The McGill Pain Questionnaire was used to assess postoperative pain intensity. The postoperative pain evaluation was performed in the first 5 minutes on entering the postanesthesia care unit (PACU), and at 30 minutes and 24 hours after the operation.

RESULTS

Our results showed a significant negative relationship between pain intensity as assessed at 5 and 30 minutes postoperatively and age. Postoperative pain intensity at 24 hours was significantly lower after low-risk surgeries lasting up to 1 hour; pain intensity was also significantly lower at 30 minutes following epidural anesthesia. When nonsteroidal anti-inflammatory drugs were not administered in the PACU, pain intensity was significantly lower at 5 minutes, 30 minutes, and 3 hours.

CONCLUSIONS

Postoperative analgesic administration should be conducted in accordance with age and surgery type. Additionally, epidural anesthesia can reduce the immediate postoperative pain intensity.

The comparison of postoperative analgesic efficacy of three-in-one-block versus fascia-iliaca blocks following femoral fracture orthopedics surgical procedures under spinal anesthesia, Gondar, Ethiopia, 2021: A prospective cohort study

INTRODUCTION

Femoral bone fracture is the predominant, lower limb orthopedic surgery that is associated with severe acute and persistent chronic pain that needs better postoperative pain management. Untreated postoperative pain results inability to do physiotherapy resulting in stiffens of joints and immobility. This study aimed to compare the postoperative analgesic efficacy of three-in-one-block versus fascia iliaca block in patients who underwent surgically treated femoral fractured patients under spinal anesthesia.

METHODS

A prospective cohort study was conducted on 110 elective surgically treated femoral fractured orthopedic patients from January to October 2021. Data were entered into epi-data 4.4.2 and imported into a statistical package of social science version 22 for analysis. Shapiro-Wilk normality test was used to check the normality of the data and normally distributed data were analyzed using Student's independent t-test, whereas non-normally distributed variables were analyzed with Mann-Whitney U-test. The comparisons of categorical parameters were analyzed using the chi-square test and Fisher's exact test. Finally p-value < 0.05 was declared to be statistically significant.

RESULT

The median and interquartile range of the postoperative numerical rating scale at rest and on movement was significantly less in three-in-one-block (3IN1B) as compared with fascia-iliaca block (FICB). But at 30 min no significantly different between the two pain management modalities. Moreover, the meantime to seek the first request of analgesia was significantly prolonged in 3IN1B compared with FICB. Regarding the total analgesic consumption, the mean total tramadol consumption was 97. 27 ± 53. 07 and 180 ± 72.96 (p < 0.001) and Diclofenac 53.18 ± 29.28 and 72 ± 43.54 (p < 0. 001) in 3IN1 and FICB, respectively.

CONCLUSION

The present study concludes that three-in-one-block provides more effective analgesia, reduced postoperative analgesic requirements, and prolonged first analgesics requests compared with fascia iliaca block, and Landmark technique fascia-iliaca block (FICB) is an alternative pain management modality in a resource-limited setting.

EEG responses to standardised noxious stimulation during clinical anaesthesia: a pilot study

Background

During clinical anaesthesia, the administration of analgesics mostly relies on empirical knowledge and observation of the patient's reactions to noxious stimuli. Previous studies in healthy volunteers under controlled conditions revealed EEG activity in response to standardised nociceptive stimuli even at high doses of remifentanil and propofol. This pilot study aims to investigate the feasibility of using these standardised nociceptive stimuli in routine clinical practice.

Methods

We studied 17 patients undergoing orthopaedic trauma surgery under general anaesthesia. We evaluated if the EEG could track standardised noxious phase-locked electrical stimulation and tetanic stimulation, a time-locked surrogate for incisional pain, before, during, and after the induction of general anaesthesia. Subsequently, we analysed the effect of tetanic stimulation on the surgical pleth index as a peripheral, vegetative, nociceptive marker.

Results

We found that the phase-locked evoked potentials after noxious electrical stimulation vanished after the administration of propofol, but not at low concentrations of remifentanil. After noxious tetanic stimulation under general anaesthesia, there were no consistent spectral changes in the EEG, but the vegetative response in the surgical pleth index was statistically significant (Hedges' g effect size 0.32 [95% confidence interval 0.12-0.77], P=0.035).

Conclusion

Our standardised nociceptive stimuli are not optimised for obtaining consistent EEG responses in patients during clinical anaesthesia. To validate and sufficiently reproduce EEG-based standardised stimulation as a marker for nociception in clinical anaesthesia, other pain models or stimulation settings might be required to transfer preclinical studies into clinical practice.

Clinical trial registration

DRKS00017829.

Symptom severity trajectories and distresses in patients undergoing video-assisted thoracoscopic lung resection from surgery to the first post-discharge clinic visit

This study aimed to characterize patients' symptom severity trajectories and distresses from video-assisted thoracoscopic lung resection to the first post-discharge clinic visit. Seventy-five patients undergoing thoracoscopic lung resection for diagnosed or suspected pulmonary malignancy prospectively recorded daily symptom severity on a 0-10 numeric scale using the MD Anderson Symptom Inventory until the first post-discharge clinic visit. The causes of postoperative distresses were surveyed, and symptom severity trajectories were analyzed using joinpoint regression. A rebound was defined as a statistically significant positive slope after a statistically significant negative slope. Symptom recovery was defined as symptom severity of ≤3 in two contiguous measurements. The accuracy of pain severity on days 1-5 for predicting pain recovery was determined using area under the receiver operating characteristic curves. We applied Cox proportional hazards models for multivariate analyses of the potential predictors of early pain recovery. The median age was 70 years, and females accounted for 48%. The median interval from surgery to the first post-discharge clinic visit was 20 days. Trajectories of several core symptoms including pain showed a rebound from day 3 or 4. Specifically, pain severity in patients with unrecovered pain had been higher than those with recovered pain since day 4. Pain severity on day 4 showed the highest area under the curve of 0.723 for predicting pain recovery (P = 0.001). Multivariate analysis identified pain severity of ≤1 on day 4 as an independent predictor of early pain recovery (hazard ratio, 2.86; P = 0.0027). Duration of symptom was the leading cause of postoperative distress. Several core symptoms after thoracoscopic lung resection showed a rebound in the trajectory. Specifically, a rebound in pain trajectory may be associated with unrecovered pain; pain severity on day 4 may predict early pain recovery. Further clarification of symptom severity trajectories is essential for patient-centered care.

A narrative review on the non-surgical treatment of chronic postoperative inguinal pain: a challenge for both surgeon and anaesthesiologist

INTRODUCTION

Chronic pain is one of the most frequent clinical problems after inguinal hernia surgery. Despite more than two decades of research and numerous publications, no evidence exists to allow for chronic postoperative inguinal pain (CPIP) specific treatment algorithms.

METHODS

This narrative review presents the current knowledge of the non-surgical management of CPIP and makes suggestions for daily practice.

RESULTS

There is a paucity for high-level evidence of non-surgical options for CPIP. Different treatment options and algorithms have been published for chronic pain patients in the last decades.

DISCUSSION AND CONCLUSION

It is suggested that non-surgical treatment is introduced in the management of all CPIP patients. The overall approach to interventions should be pragmatic, tiered and multi-interventional, starting with least invasive and only moving to more invasive procedures upon lack of effect. Evaluation should be multidisciplinary and should take place in specialized centres. We strongly suggest to follow general guidelines for treatment of persistent pain and to build a database allowing for establishing CPIP specific evidence for optimal analgesic treatments.

Successful use of differential target multiplexed spinal cord stimulation for chronic postsurgical abdominal pain

Introduction

Recent advances in stimulation techniques have improved the efficacy and expanded the applicability of spinal cord stimulation (SCS). Among these techniques, there are no reports on the efficacy of differential target multiplexed (DTM) SCS for chronic postsurgical pain (CPSP) after abdominal surgery. Therefore, we present the successful use of DTM SCS for CPSP after distal pancreatectomy.

Methods

A 49-year-old man with hypertension and severe chronic low back pain presented with neuropathic CPSP involving the left abdomen in the area of a laparotomy incision. His pain was refractory to conservative treatment and was rated 10 on a numerical rating scale (NRS). He underwent permanent implantation of a pulse generator after a 14-day trial stimulation.

Results

Chronic postsurgical pain was well controlled (NRS 1-2) at a 3-month follow-up with DTM SCS.

Conclusion

Differential target multiplexed SCS can be a new treatment option for neuropathic CPSP that is resistant to conservative treatment. It is important to further examine the characteristics of CPSP and identify appropriate candidates for the successful use of DTM SCS.

Emulsion-induced polymersomes taming tetrodotoxin for prolonged duration local anesthesia

Injectable local anesthetics that can provide a continuous nerve block approximating the duration of a pain state would be a life-changing solution for patients experiencing post-operative pain or chronic pain. Tetrodotoxin (TTX) is a site 1 sodium channel blocker that is extremely potent compared to clinically used local anesthetics. Challengingly, TTX doses are limited by its associated systemic toxicity, thus shortening the achievable duration of nerve blocks. Here, we explore emulsion-induced polymersomes (EIP) as a drug delivery system to safely use TTX for local anesthesia. By emulsifying hyperbranched polyglycerol-poly (propylene glycol)-hyperbranched polyglycerol (HPG-PPG-HPG) in TTX aqueous solution, HPG-PPG-HPG self-assembled into micrometer-sized polymersomes within seconds. The formed polymersomes have microscopically visible internal aqueous pockets that encapsulate TTX with an encapsulation efficiency of up to 94%. Moreover, the polymersomes are structurally stable, enabling sustained TTX release. In vivo, the freshly prepared EIP/TTX formulation can be directly injected and increased the tolerated dose of TTX in Sprague-Dawley rats to 11.5 μg without causing any TTX-related systemic toxicity. In the presence of the chemical penetration enhancer (CPE) sodium octyl sulfate (SOS), a single perineural injection of EIP/TTX/SOS formulation produced a reliable sciatic nerve block for 22 days with minimal local toxicity.

Chronic craniomandibular pain after craniotomy: A long-term clinical study

OBJECTIVE

Chronic craniomandibular/cervical pain and temporomandibular disorders have not been studied in patients who had a craniotomy several years previously. The aim of the current clinical work was to address these issues.

METHODS

A total group of 150 ambulant patients who had a previous craniotomy was subclassified according to whether or not the temporalis muscle was manipulated.

RESULTS

The average incidence of multiple subsite regional head and neck pain was 69.3% a number of years after a craniotomy. Evidence of internal derangement of the temporomandibular joint was significantly higher in the group that required manipulation of the temporalis muscle during the procedure.

CONCLUSION

The pattern of chronic craniomandibular/cervical pain experienced years after a craniotomy supports the brain neuromatrix theory of pain.

Rethinking the definition of chronic postsurgical pain: composites of patient-reported pain-related outcomes vs pain intensities alone

ABSTRACT

Chronic postsurgical pain (CPSP) is defined by pain intensity and pain-related functional interference. This study included measures of function in a composite score of patient-reported outcomes (PROs) to investigate the incidence of CPSP. Registry data were analyzed for PROs 1 day and 12 months postoperatively. Based on pain intensity and pain-related interference with function, patients were allocated to the groups " CPSPF " (at least moderate pain with interference), " mixed " (milder symptoms), and " no CPSPF ". The incidence of CPSPF was compared with CPSP rates referring to published data. Variables associated with the PRO-12 score (composite PROs at 12 months; numeric rating scale 0-10) were analyzed by linear regression analysis. Of 2319 patients, 8.6%, 32.5%, and 58.9% were allocated to the groups CPSPF , mixed , and no CPSPF , respectively. Exclusion of patients whose pain scores did not increase compared with the preoperative status, resulted in a 3.3% incidence. Of the patients without pre-existing pain, 4.1% had CPSPF. Previously published pain cutoffs of numeric rating scale >0, ≥3, or ≥4, used to define CPSP, produced rates of 37.5%, 9.7%, and 5.7%. Pre-existing chronic pain, preoperative opioid medication, and type of surgery were associated with the PRO-12 score (all P < 0.05). Opioid doses and PROs 24 hours postoperatively improved the fit of the regression model. A more comprehensive assessment of pain and interference resulted in lower CPSP rates than previously reported. Although inclusion of CPSP in the ICD-11 is a welcome step, evaluation of pain characteristics would be helpful in differentiation between CPSPF and continuation of pre-existing chronic pain.

Chronic pain after surgery and trauma: current situation and future directions

Chronic post-surgical pain (CPSP) stands as a major health issue. The unchanged incidence over the last two decades underlines both the failure of predictive models developed until now and the lack of efficacy of common “preventive” strategies (pharmacotherapy and regional analgesic techniques) applied in current clinical practice. The recognition of CPSP as a disease and the release of a common definition of the condition is an important progress in the field. CPSP predictive scores exist but none has presently demonstrated an impact on patient care. New clinical directions based on the resolution of postoperative pain, a complex and highly dynamic process supported by individual pain trajectories, argue for predictive models and preventive strategies extended to the subacute pain period i.e. after hospital discharge.

The "STOP Pain" Questionnaire: using the Plan-Do-Study-Act model to implement a patient-family preferences-informed questionnaire into a pediatric transitional pain clinic

BACKGROUND

Patient engagement is an important tool for quality improvement (QI) and optimizing the uptake of research findings. The Plan-Do-Study-Act (PDSA) model is a QI tool that encourages ongoing evaluation of clinical care, thus improving various aspects of patient care. Ascertaining pediatric patient priorities for a pain questionnaire in the post-acute, or transitional pain, setting is important to guide clinical care since active engagement with the population of interest can optimize uptake. We used the PDSA model to adapt a chronic pain questionnaire for the pediatric transitional pain setting to reflect pediatric patient and parent/guardian preferences and to form an example of how the PDSA model can be used to improve clinical care through patient engagement.

METHODS

This project employed the PDSA model to adapt the pediatric Ontario Chronic Pain Questionnaire for use in the pediatric Transitional Pain Service (pedTPS) setting. Plan: Following reviewing the Ontario Chronic Pain Questionnaire and literature on pain questionnaire development, goal-based questions, questions on pain location, relevant Patient-Reported Outcomes Measurement Information System (PROMIS^®) measures and the Pain Catastrophizing Scale, child (PCS-C) and parent (PCS-P), informed the questionnaire. Do: The questionnaire and a satisfaction survey were sent to patients and families through Research Electronic Data Capture (REDCap™).

STUDY

Results from the satisfaction survey were analyzed. Act: Using descriptive statistics employing ordinal mixed-models with random effects, ANOVA, and double-blinded qualitative thematic coding, questionnaire preferences were analyzed and the questionnaire was adapted accordingly before implementation into the (pedTPS).

RESULTS

Eighty-eight questionnaires and satisfaction surveys were analyzed from 69 respondents (32 patients; 37 parents/guardians). Sixty-six (75.00%) surveys indicated satisfaction with the questionnaire. A combined 77 (87.50%) "strongly agreed" (25/88) or "agreed" (52/88) that the questionnaire language was clear. The application of suggested changes to the questionnaire resulted in four versions across the project timeline, which reflected patient and parent/guardian preferences for questions that reflect the themes, "Story"; "Time-Optimal"; and "Pertinent" ("STOP"). There were no statistically significant differences in satisfaction across the versions due to sample size.

CONCLUSION

Most respondents were satisfied with the questionnaire and prefer "STOP" questions. Future studies will focus on testing the questionnaire for validity and reliability across pedTPS populations.

Risk factors for chronic postsurgical pain in visceral surgery: a matched case–control analysis

Purpose

Chronic postsurgical pain (CPSP) after abdominal visceral surgery is an underestimated long-term complication with relevant impact on health-related quality of life and socioeconomic costs. Early identification of affected patients is important. We aim to identify the incidence and risk factors for CPSP in this patient population.

Methods

Retrospective case–control matched analysis including all patients diagnosed with CPSP after visceral surgery in our institution between 2016 and 2019. One-to-two case–control matching was based on operation category (HPB, upper-GI, colorectal, transplantation, bariatric, hernia and others) and date of surgery. Potential risk factors for CPSP were identified using conditional multivariate logistic regression.

Results

Among a cohort of 3730 patients, 176 (4.7%) were diagnosed with CPSP during the study period and matched to a sample of 352 control patients. Independent risk factors for CPSP were age under 55 years (OR 2.64, CI 1.51–4.61), preexisting chronic pain of any origin (OR 3.42, CI 1.75–6.67), previous abdominal surgery (OR 1.99, CI 1.11–3.57), acute postoperative pain (OR 1.29, CI 1.16–1.44), postoperative use of non-steroidal anti-inflammatory drugs (OR 3.73, OR 1.61–8.65), opioid use on discharge (OR 3.78, CI 2.10–6.80) and length of stay over 3 days (OR 2.60, CI 1.22–5.53). Preoperative Pregabalin intake was protective (OR 0.02, CI 0.002–0.21).

Conclusion

The incidence of CPSP is high and associated with specific risk factors, some of them modifiable. Special attention should be given to sufficient treatment of preexisting chronic pain and acute postoperative pain.

Use of regional analgesia to prevent the conversion from acute to chronic pain

PURPOSE OF REVIEW

Chronic post-surgical pain (CPSP) prevalence has not changed over the past decades what questions the efficacy of preventive strategies. Regional analgesia is used to control acute pain, but preventive effect on CPSP remains debated. Failures and future application of regional analgesia to prevent transition from acute to chronic pain will be discussed.

RECENT FINDINGS

After thoracotomy, perioperative regional analgesia does not seem to prevent CPSP. After breast cancer surgery, paravertebral block might prevent CPSP intensity and impact on daily life up to 12 months, particularly in high catastrophizing patients. In knee arthroplasty, perioperative regional analgesia or preoperative genicular nerve neuroablation do not prevent CPSP, although current studies present several bias. The protective role of effective regional analgesia and early pain relief in trauma patients deserves further studies.

SUMMARY

Regional analgesia failure to prevent CPSP development should prompt us to reconsider its perioperative utilization. Patients' stratification, for example high-pain responders, might help to target those who will most benefit of regional analgesia. The impact of regional analgesia on secondary pain-related outcomes such as intensity and neuropathic character despite no difference on CPSP incidence requires more studies. Finally, the preventive effect of regional analgesia targeted interventions on CPSP in patients suffering from severe subacute pain deserves to be assessed.

Acute pain assessments and records: a pilot study of digital transformation

BACKGROUND

Pain is a leading cause of disability worldwide. Pain assessments are an essential part of evidence-based care and management. Among comparable care providers, there is variation in how nurses document assessments as well as the content in them, and there is a notable associated administrative burden.

AIMS

This study evaluated the impact and significance of a new, structured, digitised pain assessment form from quality, safety and efficiency standpoints.

METHODS

Samples of pain assessments were examined at three consecutive stages: first, the pre-existing form was used, then the new structured form was introduced and, finally, the structured form was taken away and nurses went back to completing the original form. Assessments were scored by two clinical analysts against 18 clinically defined pain-related characteristics and factors. The time taken to extract and interpret the assessments was also recorded. Statistically significant changes were assessed using Welch's t-tests and Fisher's exact tests.

FINDINGS

There was a significant improvement in data quality using the new structured form compared with the pre-existing template, including an increase in the capture of five safety-related variables. Less time was needed to extract and interpret data with the new form.

CONCLUSION

Intelligent structured forms are highly effective for documenting pain assessments, and offer notable benefits in quality, safety, and efficiency.

Predictors and predictive effects of acute pain trajectories after gastrointestinal surgery

Few studies have investigated factors associated with acute postsurgical pain (APSP) trajectories, and whether the APSP trajectory can predict chronic postsurgical pain (CPSP) remains unclear. We aimed to identify the predictors of APSP trajectories in patients undergoing gastrointestinal surgery. Moreover, we hypothesised that APSP trajectories were independently associated with CPSP. We conducted a prospective cohort study of 282 patients undergoing gastrointestinal surgery to describe APSP trajectories. Psychological questionnaires were administered 1 day before surgery. Meanwhile, demographic characteristics and perioperative data were collected. Average pain intensity during the first 7 days after surgery was assessed by a numeric rating scale (NRS). Persistent pain intensity was evaluated at 3 and 6 months postoperatively by phone call interview. CPSP was defined as pain at the incision site or surrounding areas of surgery with a pain NRS score ≥ 1 at rest. The intercept and slope were calculated by linear regression using the least squares method. The predictors for the APSP trajectory and CPSP were determined using multiple linear regression and multivariate logistic regression, respectively. Body mass index, morphine milligram equivalent (MME) consumption, preoperative chronic pain and anxiety were predictors of the APSP trajectory intercept. Moreover, MME consumption and preoperative anxiety could independently predict the APSP trajectory slope. The incidence of CPSP at 3 and 6 months was 30.58% and 16.42% respectively. APSP trajectory and age were predictors of CPSP 3 months postoperatively, while female sex and preoperative anxiety were predictive factors of CPSP 6 months postoperatively. Preoperative anxiety and postoperative analgesic consumption can predict APSP trajectory. In addition, pain trajectory was associated with CPSP. Clinicians need to stay alert for these predictors and pay close attention to pain resolution.

Is There a Neuropathic-Like Component to Endometriosis-Associated Pain? Results From a Large Cohort Questionnaire Study

Background: Pain is one of the primary symptoms of endometriosis, a chronic inflammatory condition characterised by the presence of endometrial tissue outside the uterus. Endometriosis-associated pain is commonly considered as nociceptive in nature, but its clinical presentation suggests that it might have neuropathic-like properties in a subgroup of patients.

Methods: This is a cross sectional study using an online survey. The survey was distributed by patient support websites. The survey was composed of validated questionnaires assessing pain symptoms, psychological measures and questions about number of surgeries.

Main Results: We had 1,417 responses which met the inclusion criteria. Using standard painDETECT cut-off scores, we found that pain was classified as neuropathic in 40% of patients and as mixed neuropathic/nociceptive in a further 35%. In line with observations in other neuropathic conditions, the neuropathic subgroup reported higher pain intensities, greater psychological distress and cognitive impairment. Neuropathic pain was also more likely in those with more surgeries to the abdomen and a longer history of pain. As revealed by a cluster analysis, those with a neuropathic pain component could further be divided into two subgroups based on their sensory profile.

Conclusions: The data presented here indicate that endometriosis-associated pain includes a neuropathic-like component in a substantial proportion of women. Although further investigation is required, our finding challenges the current conceptualisation of endometriosis-associated pain as nociceptive and advocates for a new perspective on this type of pain, which is so debilitating to a large number of women.

CD8+ T cell-derived IL-13 increases macrophage IL-10 to resolve neuropathic pain

Understanding the endogenous mechanisms regulating resolution of pain may identify novel targets for treatment of chronic pain. Resolution of chemotherapy-induced peripheral neuropathy (CIPN) after treatment completion depends on CD8⁺ T cells and on IL-10 produced by other cells. Using Rag2^–/– mice lacking T and B cells and adoptive transfer of Il13^–/– CD8⁺ T cells, we showed that CD8⁺ T cells producing IL-13 were required for resolution of CIPN. Intrathecal administration of anti–IL-13 delayed resolution of CIPN and reduced IL-10 production by dorsal root ganglion macrophages. Depleting local CD206⁺ macrophages also delayed resolution of CIPN. In vitro, TIM3⁺CD8⁺ T cells cultured with cisplatin, apoptotic cells, or phosphatidylserine liposomes produced IL-13, which induced IL-10 in macrophages. In vivo, resolution of CIPN was delayed by intrathecal administration of anti-TIM3. Resolution was also delayed in Rag2^–/– mice reconstituted with Havcr2 (TIM3)^–/– CD8⁺ T cells. Our data indicated that cell damage induced by cisplatin activated TIM3 on CD8⁺ T cells, leading to increased IL-13 production, which in turn induced macrophage IL-10 production and resolution of CIPN. Development of exogenous activators of the IL-13/IL-10 pain resolution pathway may provide a way to treat the underlying cause of chronic pain.

Perioperative Dexmedetomidine or Lidocaine Infusion for the Prevention of Chronic Postoperative and Neuropathic Pain After Gynecological Surgery: A Randomized, Placebo-Controlled, Double-Blind Study

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.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40122-022-00361-5.

Association of Pre-operative Functional Disability with Chronic Postsurgical Pain: A Prospective Observational Study

BACKGROUND

Chronic postsurgical pain negatively affects postoperative recovery. We aimed to assess the association between pre-operative functional disability and chronic postsurgical pain.

METHODS

This secondary analysis of a prospective observational study included 920 inpatients aged≥55 years undergoing elective abdominal surgery. We assessed functional disability using the 12-item World Health Organization Disability Assessment Schedule 2.0 before surgery and measured postoperative pain using a numerical rating scale at a postanaesthetic clinic 3 months and 1 year after surgery. We performed multiple logistic regression analysis to determine associations with chronic postsurgical pain 1 year after surgery. We analysed the sequential pain score using a mixed-effects model in patients with and without pre-operative functional disability. The primary outcome in this study was chronic postsurgical pain and its associated factors with a focus on preoperative functional disability. The secondary outcome was pain trajectories in patients with and without preoperative functional disability.

RESULTS

Of the 899 patients included in the analysis, 11.9% had chronic postsurgical pain 1 year later. The multiple logistic regression analysis revealed that pre-operative functional disability was associated with this outcome (OR 2.80, 95% CI, 1.70 to 4.59) as well as use of pre-operative pain medication (OR 2.74, 95% CI, 1.24 to 6.03) and pain numerical rating scale at the postanaesthetic clinic (OR 1.19, 95% CI 1.10 to 1.29). The pain trajectories were different in the presence or absence of functional disability (P<0.001) and the time of measurement (P<0.001).

CONCLUSIONS

Pre-operative functional disability was associated with chronic postsurgical pain and pain trajectories.

Preventing Persistent Postsurgical Pain: A Systematic Review and Component Network Meta-analysis

BACKGROUND AND OBJECTIVES

Evidence for perioperative methods to prevent persistent postsurgical pain (PPP) is uncertain, in part because few treatments have been directly compared. Here we have used component network meta-analysis (cNMA) to incorporate both direct and indirect evidence in the evaluation of the efficacy and tolerability of pharmacological and neural block treatments.

DATABASES AND DATA TREATMENT

We searched the Cochrane Central Registry of Controlled Trials, Embase, MEDLINE, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry up to January 2021, for randomized, double-masked, controlled trials that reported the prevalence of PPP. We assessed trial quality with the Cochrane risk of bias tool (RoB 2.0). We analyzed the results with frequentist cNMA models. The primary outcome was the relative risk (RR) of PPP. We assessed efficacy in relation to a clinically important effect size of RR = 0.9, which is a 10% improvement with treatment.

RESULTS

The analysis included 107 trials (13,553 participants) of 13 treatments. The effects of complex interventions were the multiplicative effects of their components. Compared with placebo, serotonin-norepinephrine reuptake inhibitors (SNRIs), neural block alone, or in combination with NMDA receptor blockers or gabapentanoids were effective. Treatments with benefit in the immediate post-operative period predicted a reduced risk of PPP.

CONCLUSIONS

Several treatments and treatment combinations effectively reduce PPP prevalence. Pain outcomes in the immediate postoperative period are an important mediator of PPP. Multimodal interventions can be analyzed using cNMA.

The analgesic effects of ulinastatin either as a single agent or in combination with sufentanil: A novel therapeutic potential for postoperative pain

Ulinastatin is a broad-spectrum protease inhibitor widely used for the treatment of various inflammation-related diseases owing to its recognized excellent anti-inflammatory and cytoprotective properties. However, whether ulinastatin can relieve postoperative pain remains unclear. In this study, we evaluated the analgesic effects of ulinastatin administered either as a single agent or in combination with sufentanil in a validated preclinical rat model of postoperative pain induced by plantar incision. We found that incisional surgery on the hind paw of these rats induced sustained ipsilateral mechanical pain hypersensitivity that lasted for at least 10 days. A single intraperitoneal (i.p.) injection of ulinastatin prevented the development and reversed the maintenance of incision-induced mechanical pain hypersensitivity in a dose-dependent manner. However, ulinastatin had no effect on the baseline nociceptive threshold. Moreover, repeated i.p. injections of ulinastatin persistently attenuated incision-induced mechanical pain hypersensitivity and promoted recovery from the surgery. The rats did not develop any analgesic tolerance over the course of repeated injections of ulinastatin. A single i.p. injection of ulinastatin was also sufficient to inhibit the initiation and maintenance of incision-induced hyperalgesic priming when the rats were subsequently challenged with an ipsilateral intraplantar prostaglandin E2 injection. Furthermore, the combined administration of ulinastatin and sufentanil significantly enhanced the analgesic effect of sufentanil on postoperative pain, which involved mechanisms other than a direct influence on opioid receptors. These findings demonstrated that ulinastatin had a significant analgesic effect on postoperative pain and might be a novel pharmacotherapeutic agent for managing postoperative pain either alone or as an adjuvant.

Psychological factors and trajectories of post-surgical pain: A longitudinal prospective study

A significant proportion of patients do not experience relief from pain during the early postsurgical period after joint arthroplasty and are at risk for developing chronic pain. The objectives of this study were to identify biopsychosocial factors associated with acute postsurgical pain trajectories and with pain intensity and interference after 1, 3, and 12 months. Two hundred ten patients listed for joint arthroplasty filled a presurgical battery of questionnaires assessing presurgical pain intensity, catastrophizing, emotional distress, state anxiety and depression, self-efficacy, central sensitization, and executive functions. From the day after surgery, they were asked to fill a 7-day diary, including questions about postsurgical pain and postsurgical state catastrophizing. Finally, they provided data about pain intensity and interference after 1, 3, and 12 months. Predictors of acute pain trajectories were investigated using multilevel growth curve analysis. Results showed that central sensitization was a predictor of the intercept of pain trajectories and daily postsurgical catastrophizing was a significant covariate of pain intensity in the acute phase. Analyses of follow-up data showed that central sensitization was a predictor of pain intensity and pain interference at 3 and 12 months, that emotional distress was related with pain intensity and interference at 1 month, and with pain interference at 3 months, and that cognitive flexibility was associated with pain interference at 1 month. Assessment of these factors could enable to identify patients at risk for worse outcomes and to plan targeted treatments to be implemented during the patient's inward stay.

Waking Up in Pain: a prospective unselected cohort study of pain in 3702 patients immediately after surgery in the Danish Realm

BACKGROUND

Acute and persistent pain after surgery is well described. However, no large-scale studies on immediate postoperative pain in the operating room (OR) exist, hindering potential areas of research to improve clinical outcomes. Thus, we aimed to describe the occurrence and severity of immediate postoperative pain in a large, unselected cohort.

METHODS

This was a prospective cohort study, encompassing all procedures in 31 public hospitals in the Danish Realm, during a 5-day period including the weekend. Data on procedures and anesthesia were collected and the main outcome was occurrence of moderate or severe pain in the OR. Secondary outcomes included pain, sedation and nausea in the OR or during the first 15 min in the postanesthesia care unit (PACU) including relevant risk factors. Descriptive and logistic regression statistics were used.

RESULTS

A total of 3675 procedures were included for analysis (87% inclusion rate). Moderate or severe pain occurred in 7.4% (95% CI 6.5% to 8.3%) of cases in the OR immediately after awakening, rising to 20.2% in the OR and/or PACU. Large intraprocedure and interprocedure variations occurred (0.0%-37.5%), and in 20% of cases with epidural-general anesthesia patients experienced moderate or severe pain. Independent risk factors were female sex, younger age, preoperative pain, daily opioid use and major surgical procedures.

CONCLUSION

Moderate or severe pain in the immediate postoperative phase occurred in 20% of all cases with procedure and anesthesiological technique variations, suggesting a need for identification of relevant procedure-specific risk factors and development of preventive treatments.

TRIAL REGISTRATION NUMBER

RoPR ID 43191.

Identification of preoperative predictors for acute postsurgical pain and for pain at three months after surgery: a prospective observational study

Identifying patients at risk is the start of adequate perioperative pain management. We aimed to identify preoperative predictors for acute postsurgical pain (APSP) and for pain at 3 months after surgery to develop prediction models. In a prospective observational study, we collected preoperative predictors and the movement-evoked numerical rating scale (NRS-MEP) of postoperative pain at day 1, 2, 3, 7, week 1, 6 and 3 months after surgery from patients with a range of surgical procedures. Regression analyses of data of 2258 surgical in- and outpatients showed that independent predictors for APSP using the mean NRS-MEP over the first three days after surgery were hospital admittance, female sex, higher preoperative pain, younger age, pain catastrophizing, anxiety, higher score on functional disability, highest categories of expected pain, medical specialty, unknown wound size, and wound size > 10 cm compared to wound size ≤ 10 cm (RMSE = 2.11). For pain at three months, the only predictors were preoperative pain and a higher score on functional disability (RMSE = 1.69). Adding pain trajectories improved the prediction of pain at three months (RMSE = 1.37). Our clinically applicable prediction models can be used preoperatively to identify patients at risk, as well as in the direct postoperative period.

AAAPT Diagnostic Criteria for Acute Thoracic Surgery Pain

Patients undergoing thoracic surgery experience particular challenges for acute pain management. Availability of standardized diagnostic criteria for identification of acute pain after thoracotomy and video assisted thoracic surgery (VATS) would provide a foundation for evidence-based management and facilitate future research. The Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks (ACTTION) public-private partnership with the United States Food and Drug Administration, the American Pain Society (APS), and the American Academy of Pain Medicine (AAPM) formed the ACTTION-APS-AAPM Pain Taxonomy (AAAPT) initiative to address absence of acute pain diagnostic criteria. A multidisciplinary working group of pain experts was invited to develop diagnostic criteria for acute thoracotomy and VATS pain. The working group used available studies and expert opinion to characterize acute pain after thoracotomy and VATS using the 5-dimension taxonomical structure proposed by AAAPT (i.e., core diagnostic criteria, common features, modulating factors, impact/functional consequences, and putative mechanisms). The resulting diagnostic criteria will serve as the starting point for subsequent empirically validated criteria. PERSPECTIVE ITEM: This article characterizes acute pain after thoracotomy and VATS using the 5-dimension taxonomical structure proposed by AAAPT (ie, core diagnostic criteria, common features, modulating factors, impact and/or functional consequences, and putative mechanisms).

Predictive value of quantitative sensory testing for acute and chronic postsurgical pain after total joint arthroplasty: a systematic review

ABSTRACT

Quantitative sensory testing (QST) can be useful to identify high-risk patients for the development of chronic postsurgical pain. This systematic review aims to assess if presurgical sensory sensitivity measured using QST is associated with acute and chronic postsurgical pain after total joint arthroplasty. A systematic search was performed in September 2020 in PubMed, EMBASE, Web of Science, and Scopus, using terms related to total joint arthroplasty and QST. Prospective studies were included if they reported an association between presurgical QST and postsurgical pain in adults with osteoarthritis undergoing primary unilateral total joint arthroplasty. From 2994 identified studies, 18 met the inclusion criteria (1869 patients). Total knee arthroplasty was the most common surgery (16 studies), and pressure pain threshold was the most common test (11 studies), followed by dynamic measures (9 studies). Postsurgical pain was assessed at acute (5 studies), subacute (2 studies), and chronic (13 studies) time points. Risk of bias was assessed using the Quality in Prognosis Studies tool and evaluated as low to moderate in most domains. Fourteen studies reported at least one statistically significant association between QST and pain (acute: 4 studies, subacute: 1 study, and chronic: 9 studies). Pressure pain threshold was associated with postsurgical pain in 6 studies (of 11, 55%), heat pain threshold in 2 studies (of 6, 33%), conditioned pain modulation in 1 study (of 6, 17%), and temporal summation of pain in 5 studies (of 8, 63%). The predictive role of presurgical QST for postarthroplasty pain remains unclear, mainly because of heterogeneous methodologies and inconsistent results.

T Cells as Guardians of Pain Resolution

Despite successful research efforts aimed at understanding pain mechanisms, there is still no adequate treatment for many patients suffering from chronic pain. The contribution of neuroinflammation to chronic pain is widely acknowledged. Here, we summarize findings indicating that T cells play a key role in the suppression of pain. An active contribution of the immune system to resolution of pain may explain why immunosuppressive drugs are often not sufficient to control pain. This would also imply that dysregulation of certain immune functions promote transition to chronic pain. Conversely, stimulating the endogenous immune-mediated resolution pathways may provide a potent approach to treat chronic pain.

Predicting long-term postsurgical pain by examining the evolution of acute pain

BACKGROUND

Increased acute postoperative pain intensity has been associated with the development of persistent postsurgical pain (PPP) in mechanistic and clinical investigations, but it remains unclear which aspects of acute pain explain this linkage.

METHODS

We analysed clinical postoperative pain intensity assessments using symbolic aggregate approximations (SAX), a graphical way of representing changes between pain states from one patient evaluation to the next, to visualize and understand how pain intensity changes across sequential assessments are associated with the intensity of postoperative pain at 1 (M1) and 6 (M6) months after surgery. SAX-based acute pain transition patterns were compared using cosine similarity, which indicates the degree to which patterns mirror each other.

RESULTS

This single-centre prospective cohort study included 364 subjects. Patterns of acute postoperative pain sequential transitions differed between the 'None' and 'Severe' outcomes at M1 (cosine similarity 0.44) and M6 (cosine similarity 0.49). Stratifications of M6 outcomes by preoperative pain intensity, sex, age group, surgery type and catastrophising showed significant heterogeneity of pain transition patterns within and across strata. Severe-to-severe acute pain transitions were common, but not exclusive, in patients with moderate or severe pain intensity at M6.

CONCLUSIONS

Clinically, these results suggest that individual pain-state transitions, even within patient or procedural strata associated with PPP, may not alone offer good predictive information regarding PPP. Longitudinal observation in the immediate postoperative period and consideration of patient- and surgery-specific factors may help indicate which patients are at increased risk of PPP.

SIGNIFICANCE

Symbolic aggregate approximations of clinically obtained, acute postoperative pain intraday time series identify different motifs in patients suffering moderate to severe pain 6 months after surgery.

Chronic pain after breast surgery: incidence, associated factors, and impact on quality of life, an observational prospective study

BACKGROUND

Chronic pain after breast surgery (CPBS) has a disabling impact on postoperative health status. Mainly because of the lack of a clear definition, inconsistency does exist in the literature concerning both the actual incidence and the risk factors associated to CPBS. The aim of this prospective, observational study is to describe the incidence of and risk factors for CPBS, according to the definition provided by the IASP taskforce. The impact of CPBS on patients' function and quality of life is also described.

METHODS

Women aged 18+ undergoing oncological or reconstructive breast surgery from Jan until Apr 2018 at the Breast Unit of Careggi Hospital (Florence, Italy) were prospectively observed. Postoperative pain was measured at 0 h, 3 h, 6 h, 12 h, 24 h, 48 h, and 3 months (CPBS) after surgery. Preoperative, intraoperative, and postoperative factors were compared in CPBS and No-CPBS groups through multivariate logistic regression analysis.

RESULTS

Among the 307 patients considered in this study, the incidence of CPBS was 28% [95% CI 23.1-33.4%]. Results from the logistic regression analysis suggest that axillary surgery (OR [95% CI], 2.99 [1.13-7.87], p = 0.03), preoperative use of pain medications (OR [95% CI], 2.04 [1.20-3.46], p = 0.01), and higher dynamic NRS values at 6 h postoperatively (OR [95% CI], 1.28 [1.05-1.55], p = 0.01) were all independent predictors for CPBS.

CONCLUSIONS

Chronic pain after breast surgery is a frequent complication. In our cohort, long-term use of analgesics for pre-existing chronic pain, axillary surgery, and higher dynamic NRS values at 6 h postoperatively were all factors associated with increased risk of developing CPBS. The possibility to early detect persistent pain, particularly in those patients at high risk for CPBS, might help physicians to more effectively prevent pain chronicisation.

TRIAL REGISTRATION

ClinicalTrials.gov registration NCT04309929 .