Psychophysical and psychological predictors of acute pain after breast surgery differ in patients with and without pre-existing chronic pain

Weak Relationships Between Psychological Factors and Experimental Pain Outcomes in Pain-Free Individuals: An Aggregate Analysis of 8 Studies

Although psychological factors such as anxiety, depression, and pain catastrophizing are known to influence pain outcomes in chronic pain populations, there are mixed results regarding whether they influence experimental pain outcomes in pain-free individuals. The objectives of this study were to determine the associations between psychological factors and experimental pain outcomes in pain-free adolescents and adults. Relationships between anxiety, depression, and pain catastrophizing and experimental pain outcomes across 8 different studies (total N = 595) were examined in different populations of pain-free adult and adolescent participants. Analyses were conducted with and without controlling for sex, age, and race. Studies were analyzed separately and as part of an aggregate analysis. Individual study analyses resulted in 136 regression models. Of these, only 8 models revealed a significant association between psychological factors and pain outcomes. The significant results were small and likely due to Type 1 error. Controlling for demographic factors had minimal effect on the results. The aggregate analyses revealed weak relationships between anxiety and pressure pain threshold (Fisher's z = -.10 [-.19, -.01]), anxiety and cold pain intensity ratings (Fisher's z = .18 [.04, .32]), and pain catastrophizing and pressure pain threshold (Fisher's z = -.14 [-.26, -.02]). Sample size calculations based on the aggregate analyses indicated that several hundred participants would be required to detect true relationships between these psychological factors and pain measures. The overall negative findings suggest that in pain-free individuals, anxiety, depression, and pain catastrophizing are not meaningfully related to experimental pain outcomes. PERSPECTIVE: Psychological variables have been shown to predict pain outcomes in chronic pain populations but these relationships may not generalize to pain-free populations. An analysis of 595 pain-free individuals across 8 studies in our lab revealed that anxiety, depression, and pain catastrophizing were not meaningfully related to experimental pain outcomes.

Risk Factors for Acute Postsurgical Pain: A Narrative Review

Acute postsurgical pain (APSP) has received growing attention as a surgical outcome. When poorly controlled, APSP can affect short- and long-term outcomes in patients. Despite the steady increase in awareness about postoperative pain and standardization of pain prevention and treatment strategies, moderate-to-severe APSP is frequently reported in clinical practice. This is possibly because pain varies widely among individuals and is influenced by distinct factors, such as demographic, perioperative, psychological, and genetic factors. This review investigates the risk factors for APSP, including gender, age, obesity, smoking history, preoperative pain history, pain sensitivity, preoperative anxiety, depression, pain catastrophizing, expected postoperative pain, surgical fear, and genetic polymorphisms. By identifying patients having an increased risk of moderate-to-severe APSP at an early stage, clinicians can more effectively manage individualized analgesic treatment protocols with a combination of pharmacological and non-pharmacological interventions. This would alleviate the transition from APSP to chronic pain and reduce the severity of APSP-induced chronic physical disability and social psychological distress.

Preoperatively assessed offset analgesia predicts acute postoperative pain following orthognathic surgery

OBJECTIVES

High intensity and longer duration of acute postoperative pain are generally associated with a higher risk of developing chronic postoperative pain. Therefore, it is important to identify the preoperative predictors for acute postoperative pain. Preoperative evaluation of offset analgesia (OA) and the Pain Catastrophising Scale (PCS) may be potential predictors for acute postoperative pain. This study aimed to investigate the relationship between preoperative OA, PCS, and acute postoperative pain following orthognathic surgery.

METHODS

Thirty patients (19 females) scheduled to undergo orthognathic surgery were included in this study. OA and PCS were evaluated preoperatively, and the patients reported their postoperative pain intensity using the visual analogue scale [0-100 mm] until it reached zero (number of days with pain). OA was induced on the dominant forearm via three consecutive painful heat pulses delivered for 5 s (T1=46 °C), 5 s (T2=47 °C), and 20 s (T3=46 °C). Subsequently, the associations between OA, PCS, and the number of days with pain were analysed.

RESULTS

The median duration of postoperative pain was 10.3 days. Multiple linear regression analysis showed a significant (p=0.0019) predictive value of OA (p=0.008) for the number of days with pain. The PCS-magnification component was positively correlated with the number of days with pain (R=0.369, p=0.045), with no predictive values of PCS-total and PCS-subscale scores observed.

CONCLUSIONS

Preoperative evaluation of OA may be a new individualised, predictive tool for the number of days with acute postoperative pain following orthognathic surgery; hence, a possible biomarker for the patient's vulnerability to developing chronic postoperative pain.

ETHICAL COMMITTEE NUMBER

The study was approved by the Ethics Committee of Meikai University (A1624, A2113).

TRIAL REGISTRY NUMBER

This study was registered in the University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR) Clinical Trial (Unique ID: UMIN000026719, UMIN000046957).

Interplay between noxious heat sensitivity and temporal summation magnitude in patients with fibromyalgia and long-term opioid use

Introduction

In chronic pain conditions such as fibromyalgia (FM), pain amplification within the central nervous system, or "central sensitization," may contribute to the development and maintenance of chronic pain. Chronic pain treatments include opioid therapy, and opioid therapy may maladaptively increase central sensitization, particularly in patients who take opioids long-term. However, it has remained unknown how central sensitization is impacted in patients who use opioids long-term.

Methods

To investigate how long-term opioid therapy affects central sensitization, we used the validated measure of temporal summation. The temporal summation measurement consists of applying a series of noxious stimuli to a patient's skin and then calculating changes in the patient's pain rating to each stimulus. Using this measurement, we evaluated temporal summation in study participants with fibromyalgia who take opioids long-term (i.e., greater than 90 days duration; n = 24, opioid-FM). We compared opioid-FM responses to 2 control groups: participants with fibromyalgia who do not take opioids (n = 33, non-opioid FM), and healthy controls (n = 31). For the temporal summation measurement, we applied a series of 10 noxious heat stimuli (sensitivity-adjusted temperatures) to the ventral forearm (2s duration of each stimulus, applied once every 3 s). Additionally, we collected responses to standard pain and cognitive-affective questionnaires to assess pain severity and other factors.

Results and discussion

Group differences in sensitivity-adjusted stimulus temperatures were observed, with only the non-opioid FM group requiring significantly lower stimulus temperatures (The opioid-FM group also required lower temperatures, but not significantly different from the control group). However, all 3 groups exhibited similar magnitudes of temporal summation. Across combined FM groups, temporal summation negatively correlated with pain severity (r = -0.31, p = 0.021). Within the opioid-FM group, higher pain sensitivity to heat (i.e., lower sensitivity-adjusted temperatures) showed a trend relationship with higher opioid dosage (r = -0.45, p = 0.036), potentially reflective of opioid-related hyperalgesia. Our findings also indicated that heightened pain severity may skew sensitivity-adjusted temporal summation, thereby limiting its utility for measuring central sensitization. Overall, in participants taking opioids, temporal summation may be influenced by hypersensitivity to heat pain, which appeared to vary with opioid dosage.

Exploring the Effect of Pain Sensitive Questionnaire on Guiding Intravenous Analgesia After Cesarean Section: A Randomised Double Blind Controlled Trial

Objective

This study investigates the effect of the Pain Sensitivity Questionnaire (PSQ) in guiding patient controlled intravenous analgesia (PCIA) on postoperative analgesia in women undergoing cesarean section.

Methods

A total of 160 women who were to undergo a cesarean section under combined spinal and epidural anaesthesia were included in this study. Women with a preoperative PSQ <4 were randomly divided into a low pain-sensitive control group (LC group), and a low pain-sensitive observation group (LO group), and women with preoperative PSQ >6 were randomly divided into a high pain-sensitive control group (HC group) and a high pain-sensitive observation group (HO group). After the surgery, patients received the pump butorphanol concentration was 3.5 µg·kg-1·h-1 in the LC and HC groups, 3.0 µg·kg-1·h-1 in the LO group and 4.0 µg·kg-1·h-1 in the HO group.To compare the analgesic effects of postoperative PCIA and postoperative recovery in women.

Results

Wound pain and uterine contraction pain VAS scores at rest and activity were significantly lower in the LC group than in the LO group at 4 and 8 h postoperatively (P<0.05). Similarly, wound pain and uterine contraction pain VAS scores at rest and activity were significantly lower in the HO group than in the HC group at 8, 12, and 24 h postoperatively (P<0.05). The Ramsay scores were significantly higher in the LC than in the LO groups at 4, 8, 12, 24, and 48 h postoperatively (P<0.05), but there was no statistically significant difference between the Ramsay scores in the HC group and the HO group. There was no statistical difference in any of the post-operative recoveries (P>0.05).

Conclusion

Compared to the weight-based postoperative PCIA, the PSQ-based postoperative PCIA has better analgesic effects and can improve maternal satisfaction with postoperative analgesia.

Pain-related cognitions and emotional distress are not associated with conditioned pain modulation: an explorative analysis of 1142 participants with acute, subacute, and chronic pain

ABSTRACT

Reduced conditioned pain modulation (CPM) and psychological distress co-occur frequently in many pain conditions. This study explored whether common negative pain cognitions and emotional factors were related to lower CPM in individuals across the spectrum from acute to chronic pain. Previously collected data on the CPM effect, pain-related cognitions (fear of movement, pain catastrophizing), and emotional distress (depression, anxiety) through questionnaires from 1142 individuals with acute, subacute, or chronic pain were used. The presence of negative psychological factors was dichotomized according to cutoff values for questionnaires. Associations between the presence of each negative psychological factor and the amplitude of pain reduction in the CPM paradigm was explored with Generalized Linear Models adjusted for sex, age, body mass index, and pain duration. A secondary analysis explored the cumulative effect of psychological factors on CPM. When dichotomized according to cutoff scores, 20% of participants were classified with anxiety, 19% with depression, 36% with pain catastrophizing, and 48% with fear of movement. The presence of any negative psychological factor or the cumulative sum of negative psychological factors was associated with lower CPM (individual factor: β between -0.15 and 0.11, P ≥ 0.08; total: β between -0.27 and -0.12, P ≥ 0.06). Despite the common observation of psychological factors and reduced CPM in musculoskeletal pain, these data challenge the assumption of a linear relationship between these variables across individuals with acute, subacute, and chronic pain. Arguably, there was a nonsignificant tendency for associations in nonexpected directions, which should be studied in a more homogenous population.

Mobile care app development process: using the ADDIE model to manage symptoms after breast cancer surgery (step 1)

The use of mobile applications is widespread in patient monitoring or education today. This study aims to describe the design and development process of a mobile app that supports patient self-care after breast cancer surgery. We used the ADDIE model to develop and test the mobile app. ADDIE (Analysis, Design, Development, Implementation, Evaluation) is a systematic approach based on a standard instructional design model for creating training materials. The model consists of five phases, each with its own set of steps. Once the steps within each phase are completed, the model progresses to the next phase, ultimately resulting in a "usable" product. Different team collaborations were established within each phase, and support was obtained from multiple experts during the design process. Thanks to this model, the information that patients need was transformed into a technological product. This article, which explains the stages of the product design process for mobile applications, provides information that may be helpful to researchers working on similar products.

Derivation of a clinical prediction rule for chronic post-surgical pain after total knee arthroplasty considering biopsychosocial factors: A prospective cohort study

BACKGROUND

Biopsychosocial factors are involved in the occurrence of chronic post-surgical pain (CPSP) after total knee arthroplasty (TKA). The purpose of this study was to develop a clinical prediction rule (CPR) that considers biopsychosocial factors to predict which patients are more likely to develop CPSP after TKA.

METHODS

CPSP after TKA was dichotomized into CPSP and non-CPSP groups using the Likert scale and Minimal clinically important difference, and binomial logistic regression analysis was performed. Cut-off values were then calculated using the extracted factors and dichotomized variables. The cut-off values and dichotomized variables were then used to derive a CPR that discriminates between groups with and without CPSP.

RESULTS

Seventy-one TKA patients were included in the study. Binomial logistic regression analysis revealed that Central Sensitization Inventory (CSI) and Pittsburgh Sleep Quality Index (PSQI) were associated with CPSP. The cut-off values for CSI and PSQI were 26 and 7, respectively. The CPSP scale was created using the cut-off values of CSI and PSQI, with a score of 0 for being below the cut-off values of both CSI and PSQI, 1 for being above the cut-off values of either CSI or PSQI, and 2 for being above the cut-off values of both CSI and PSQI. Furthermore, the area under the curve (AUC) for CPR created by the presence of CPSP and using the CPSP scale was significant (AUC = 0.766; P = 0.001).

CONCLUSION

The combination of the two tests, CSI and PSQI, suggested the possibility of predicting CPSP after TKA.

Exploring the sex differences in conditioned pain modulation and its biobehavioral determinants in healthy adults

BACKGROUND

Females are at greater risk of chronic pain, and exhibit higher pain sensitivity compared to males. However, sex differences in conditioned pain modulation (CPM), a neurophysiological risk factor of chronic pain, are unclear. CPM is influenced by many factors, some of which are sex-dependent. This study explored the sex differences in CPM and its biobehavioral determinants, such as blood pressure responses, physical activity levels, pain catastrophizing scores, and conditioning stimulus intensity, in young, healthy, physically active males and females.

METHODS

Twenty-six males and 24 females completed the CPM test using an electrical pain stimulus and a cold pain stimulus induced via 2 min of cold pressor test. Blood pressure was assessed at baseline and during cold pressor test, whereas cold pain ratings were obtained during cold pressor test to monitor the conditioning stimulus intensity. Physical activity was evaluated via questionnaires and accelerometer, whereas pain catastrophizing was evaluated via a questionnaire.

RESULTS

Both males and females exhibited CPM, without sex differences in the magnitude of CPM. The males showed higher resting blood pressure, higher physical activity levels, and lower pain catastrophizing scores than the females, without sex differences observed in cold pain ratings and proportion of those who met the physical activity guidelines. No correlations were observed between CPM and its determinants.

CONCLUSIONS

The results suggest the complexity of mechanisms underlying the sex differences in CPM. The sex differences in CPM, along with its determinants, may need to be examined in individuals with some risk factors for chronic pain.

Towards precision pain medicine for pain after cancer: the Cancer Pain Phenotyping Network multidisciplinary international guidelines for pain phenotyping using nociplastic pain criteria

Pain after cancer remains underestimated and undertreated. Precision medicine is a recent concept that refers to the ability to classify patients into subgroups that differ in their susceptibility to, biology, or prognosis of a particular disease, or in their response to a specific treatment, and thus to tailor treatment to the individual patient characteristics. Applying this to pain after cancer, the ability to classify post-cancer pain into the three major pain phenotypes (i.e. nociceptive, neuropathic, and nociplastic pain) and tailor pain treatment accordingly, is an emerging issue. This is especially relevant because available evidence suggests that nociplastic pain is present in an important subgroup of those patients experiencing post-cancer pain. The 2021 International Association for the Study of Pain (IASP) clinical criteria and grading system for nociplastic pain account for the need to identify and correctly classify patients according to the pain phenotype early in their treatment. These criteria are an important step towards precision pain medicine with great potential for the field of clinical oncology. Within this framework, the Cancer Pain Phenotyping (CANPPHE) Network, an international and interdisciplinary group of oncology clinicians and researchers from seven countries, applied the 2021 IASP clinical criteria for nociplastic pain to the growing population of those experiencing post-cancer pain. A manual is provided to allow clinicians to differentiate between predominant nociceptive, neuropathic, or nociplastic pain after cancer. A seven-step diagnostic approach is presented and illustrated using cases to enhance understanding and encourage effective implementation of this approach in clinical practice.

AMAZONE: prevention of persistent pain after breast cancer treatment by online cognitive behavioral therapy-study protocol of a randomized controlled multicenter trial

Background

Surviving breast cancer does not necessarily mean complete recovery to a premorbid state of health. Among the multiple psychological and somatic symptoms that reduce the quality of life of breast cancer survivors, persistent pain after breast cancer treatment (PPBCT) with a prevalence of 15–65% is probably the most invalidating. Once chronic, PPBCT is difficult to treat and requires an individualized multidisciplinary approach. In the past decades, several somatic and psychological risk factors for PPBCT have been identified. Studies aiming to prevent PPBCT by reducing perioperative pain intensity have not yet shown a significant reduction of PPBCT prevalence. Only few studies have been performed to modify psychological distress around breast cancer surgery. The AMAZONE study aims to investigate the effect of online cognitive behavioral therapy (e-CBT) on the prevalence of PPBCT.

Methods

The AMAZONE study is a multicenter randomized controlled trial, with an additional control arm. Patients (n=138) scheduled for unilateral breast cancer surgery scoring high for surgical or cancer-related fears, general anxiety or pain catastrophizing are randomized to receive either five sessions of e-CBT or online education consisting of information about surgery and a healthy lifestyle (EDU). The first session is scheduled before surgery. In addition to the online sessions, patients have three online appointments with a psychotherapist. Patients with low anxiety or catastrophizing scores (n=322) receive treatment as usual (TAU, additional control arm).

Primary endpoint is PPBCT prevalence 6 months after surgery.

Secondary endpoints are PPBCT intensity, the intensity of acute postoperative pain during the first week after surgery, cessation of postoperative opioid use, PPBCT prevalence at 12 months, pain interference, the sensitivity of the nociceptive and non-nociceptive somatosensory system as measured by quantitative sensory testing (QST), the efficiency of endogenous pain modulation assessed by conditioned pain modulation (CPM) and quality of life, anxiety, depression, catastrophizing, and fear of recurrence until 12 months post-surgery.

Discussion

With perioperative e-CBT targeting preoperative anxiety and pain catastrophizing, we expect to reduce the prevalence and intensity of PPBCT. By means of QST and CPM, we aim to unravel underlying pathophysiological mechanisms. The online application facilitates accessibility and feasibility in a for breast cancer patients emotionally and physically burdened time period.

Trial registration

NTR NL9132, registered December 16 2020.

Individualized multidisciplinary analgesia to prevent persistent postsurgical pain

PURPOSE OF REVIEW

Persistent postsurgical pain as outcome of surgery has reached more attention in the past years. In the first place because of related disability, long-term use of (opioid)analgesics and impact on the quality of life of individual patients. In addition, the individual and societal socio-economic burden of PPSP is high and increasing in the light of increasing numbers of surgery world-wide.

RECENT FINDINGS

Actual studies identified risk factors for persistent postsurgical pain in relevant patient populations. Astonishingly, most of predicting factors seem unrelated to surgery.

SUMMARY

Future perioperative practice will have to focus on identifying patients at risk for PPSP before surgery and develop/offer suitable individually tailored preventive interventions.

Multimodal prediction of pain and functional outcomes 6 months following total knee replacement: a prospective cohort study

BACKGROUND

Knee osteoarthritis (OA) is among the most common and disabling persistent pain conditions, with increasing prevalence and impact around the globe. In the U.S., the rising prevalence of knee OA has been paralleled by an increase in annual rates of total knee arthroplasty (TKA), a surgical treatment option for late-stage knee OA. While TKA outcomes are generally good, post-operative trajectories of pain and functional status vary substantially; a significant minority of patients report ongoing pain and impaired function following TKA. A number of studies have identified sets of biopsychosocial risk factors for poor post-TKA outcomes (e.g., comorbidities, negative affect, sensory sensitivity), but few prospective studies have systematically evaluated the unique and combined influence of a broad array of factors.

METHODS

This multi-site longitudinal cohort study investigated predictors of 6-month pain and functional outcomes following TKA. A wide spectrum of relevant biopsychosocial predictors was assessed preoperatively by medical history, patient-reported questionnaire, functional testing, and quantitative sensory testing in 248 patients undergoing TKA, and subsequently examined for their predictive capacity.

RESULTS

The majority of patients had mild or no pain at 6 months, and minimal pain-related impairment, but approximately 30% reported pain intensity ratings of 3/10 or higher. Reporting greater pain severity and dysfunction at 6 months post-TKA was predicted by higher preoperative levels of negative affect, prior pain history, opioid use, and disrupted sleep. Interestingly, lower levels of resilience-related "positive" psychosocial characteristics (i.e., lower agreeableness, lower social support) were among the strongest, most consistent predictors of poor outcomes in multivariable linear regression models. Maladaptive profiles of pain modulation (e.g., elevated temporal summation of pain), while not robust unique predictors, interacted with psychosocial risk factors such that the TKA patients with the most pain and dysfunction exhibited lower resilience and enhanced temporal summation of pain.

CONCLUSIONS

This study underscores the importance of considering psychosocial (particularly positively-oriented resilience variables) and sensory profiles, as well as their interaction, in understanding post-surgical pain trajectories.

Pediatric Pain Screening Tool: A Simple 9-Item Questionnaire Predicts Functional and Chronic Postsurgical Pain Outcomes After Major Musculoskeletal Surgeries

Reliable, clinic-friendly screening for Chronic postsurgical pain (CPSP) risk is unavailable. Within a prospective, observational study, we evaluated Pediatric Pain Screening Tool (PPST), a concise 9-item questionnaire, as a preoperative screening tool to identify those at higher risk for CPSP (Numerical Rating Scale > 3/10 beyond 3 months post-surgery) and poor function (disability/Functional Disability Inventory [FDI]/quality of life/ Pediatric Quality of Life) after spine fusion and Nuss procedures. Incidence of CPSP was 34.86% (38/109). We confirmed PPST scale stability, test re-test reliability (ICC = 0.68; P< .001); PPST measures were positively correlated with known CPSP risk factors (P< .001) preoperative pain (Pearson or Spearman Correlation Coefficient [SCC]:0.672), Child anxiety sensitivity index (SCC:0.357), Patient Related Outcome Measures Information System pain interference (SCC:0.569), Patient Related Outcome Measures Information System depression (SCC:0.501), Pediatric Quality of Life (SCC:-0.460) and insomnia severity index (SCC0.567). Preoperative PPST and PPST physical sub-scores (median(IQR) were higher in CPSP (2[0.5,4], 1[0,2]) compared to non-CPSP (1[0,3], 0[0,1.5]) groups (P= .026, P= .029) respectively. PPST scores/sub-scores positively correlated with higher FDI at 6 months but only PPST total and PPST psychosocial subscore correlated with higher FDI at 12 months. Based on ROC, optimal PPST cutoff for CPSP was 2 (63.9% sensitivity, 64.7% specificity). CPSP risk was high (48.94% risk) if PPST ≥ 2 (n = 47) and medium (22.81%) if PPST < 2 (n = 57) after spine/pectus surgery. General and risk-strata specific, targeted psychosocial non-pharmacological interventions, need to be studied. Findings need validation in diverse, larger cohorts. CLINICALTRIALS.GOV IDENTIFIER: NCT02998138. PERSPECTIVE: The article supports Pediatric Pain Screening Tool, a simple 9-item questionnaire, as a preoperative screening tool for CPSP and function 6-12 months after spine/pectus surgeries. PPST measures correlate with known risk factors for CPSP. Risk stratification and targeted preventive interventions in high-risk subjects are proposed.

Description and Comparison of Acute Pain Characteristics After Laparoscope-Assisted Vaginal Hysterectomy, Laparoscopic Myomectomy and Laparoscopic Adnexectomy

Purpose

To determine the characteristics of the acute pain after laparoscopic-assisted vaginal hysterectomy (LAVH), laparoscopic myomectomy (LM), and laparoscopic adnexectomy (LA) and compare them with each other.

Patients and Methods

Patients undergoing LAVH, LM, and LA under general anaesthesia at the First Affiliated Hospital of Wenzhou Medical University between December 2017 and December 2019 were selected. Their data were collected before, during, and after the surgery. We evaluated the degrees of pain in each group of patients and compared them.

Results

There were differences in the baseline characteristics of the patients in the LAVH, LM, and LA groups. The severity and incidence of postoperative pain were higher in the LAVH group than in the LM and LA groups, followed by the LM and LA groups. Compared with the LA group, the postoperative pain in the LAVH and LM groups was more complicated. The LA group had the lowest incidence of two or more types of moderate to severe pain. The LAVH and LM groups mainly had visceral pain and low back pain, and the LA group mainly had incisional pain. Shoulder pain had the lowest incidence in the three groups.

Conclusion

There were different postoperative pain characteristics after the LAVH, LM, and LA, and we should clinically adjust analgesia programs for different gynaecological laparoscopic surgeries.

Persistent Post-Mastectomy Pain: The Impact of Regional Anesthesia Among Patients with High vs Low Baseline Catastrophizing

BACKGROUND

Persistent post-mastectomy pain (PPMP) varies both in its severity and impact, with psychosocial factors such as catastrophizing conferring greater risk. Preoperative regional anesthesia (RA) is an important nonopioid therapy, but with variable success at preventing PPMP in previous reports. We previously reported that RA was associated with lower acute post-mastectomy pain and opioid use, but more prominently among patients with higher baseline catastrophizing. The current longitudinal investigation at 3, 6, and 12 months postop aimed to detect differential long-term impact of RA on PPMP among patients with high vs low catastrophizing.

METHODS

In this prospective observational study, patients (n = 123) completed preoperative psychosocial assessment and underwent mastectomy either with (n = 56) or without (n = 67) preoperative RA. Generalized estimating equation (GEE) regression analysis assessed impact of baseline catastrophizing, RA, and their interaction, on the primary outcome of pain severity index, as well as secondary outcomes including cognitive and emotional impact of pain, and persistent opioid use.

RESULTS

We observed a significant interaction between the effect of catastrophizing and RA on PPMP. Specifically, RA was associated with reduced pain severity and pain impact 3, 6, and 12 months postoperatively, but only among those with high baseline catastrophizing scores. In addition, both RA and lower catastrophizing scores were associated with lower incidence of persistent opioid use.

CONCLUSIONS

The efficacy of therapies to prevent PPMP may be importantly influenced by pain-modulatory psychosocial characteristics. These findings underscore the importance of considering individual patient factors when applying preventive treatments, and of including their assessment in future trials.

[Perioperative analgesia with nonopioid analgesics : Joint interdisciplinary consensus-based recommendations of the German Pain Society, the German Society of Anaesthesiology and Intensive Care Medicine and the German Society of Surgery]

BACKGROUND

Nonopioid analgesics are frequently used for perioperative analgesia; however, insufficient research is available on several practical issues. Often hospitals have no strategy for how to proceed, e.g., for informing patients or for the timing of perioperative administration of nonopioid analgesics.

METHODS

An expert panel representing the German national societies of pain, anaesthesiology and intensive care medicine and surgery developed recommendations for the perioperative use of nonopioid analgesics within a formal, structured consensus process.

RESULTS

The panel agreed that nonopioid analgesics shall be part of a multimodal analgesia concept and that patients have to be informed preoperatively about possible complications and alternative treatment options. Patients' history of pain and analgesic intake shall be evaluated. Patients at risk of severe postoperative pain and possible chronification of postsurgical pain shall be identified. Depending on the duration of surgery, nonopioid analgesics can already be administered preoperatively or intraoperatively so that plasma concentrations are sufficient after emergence from anesthesia. Nonopioid analgesics or combinations of analgesics shall be administered for a limited time only. An interdisciplinary written standard of care, comprising the nonopioid analgesic of choice, possible alternatives, adequate dosing and timing of administration as well as surgery-specific policies, have to be agreed upon by all departments involved. At discharge, the patient's physician shall be informed of analgesics given and those necessary after discharge. Patients shall be informed of possible side effects and symptoms and timely discontinuation of analgesic drugs.

CONCLUSION

The use of nonopioid analgesics as part of a perioperative multimodal concept should be approved and established as an interdisciplinary and interprofessional concept for the adequate treatment of postoperative pain.

[Perioperative analgesia with nonopioid analgesics : Joint interdisciplinary consensus-based recommendations of the German Pain Society, the German Society of Anaesthesiology and Intensive Care Medicine and the German Society of Surgery]

BACKGROUND

Nonopioid analgesics are frequently used for perioperative analgesia; however, insufficient research is available on several practical issues. Often hospitals have no strategy for how to proceed, e.g., for informing patients or for the timing of perioperative administration of nonopioid analgesics.

METHODS

An expert panel representing the German national societies of pain, anaesthesiology and intensive care medicine and surgery developed recommendations for the perioperative use of nonopioid analgesics within a formal, structured consensus process.

RESULTS

The panel agreed that nonopioid analgesics shall be part of a multimodal analgesia concept and that patients have to be informed preoperatively about possible complications and alternative treatment options. Patients' history of pain and analgesic intake shall be evaluated. Patients at risk of severe postoperative pain and possible chronification of postsurgical pain shall be identified. Depending on the duration of surgery, nonopioid analgesics can already be administered preoperatively or intraoperatively so that plasma concentrations are sufficient after emergence from anesthesia. Nonopioid analgesics or combinations of analgesics shall be administered for a limited time only. An interdisciplinary written standard of care, comprising the nonopioid analgesic of choice, possible alternatives, adequate dosing and timing of administration as well as surgery-specific policies, have to be agreed upon by all departments involved. At discharge, the patient's physician shall be informed of analgesics given and those necessary after discharge. Patients shall be informed of possible side effects and symptoms and timely discontinuation of analgesic drugs.

CONCLUSION

The use of nonopioid analgesics as part of a perioperative multimodal concept should be approved and established as an interdisciplinary and interprofessional concept for the adequate treatment of postoperative pain.

During capsaicin-induced central sensitization, brush allodynia is associated with baseline warmth sensitivity, whereas mechanical hyperalgesia is associated with painful mechanical sensibility, anxiety and somatization

BACKGROUND

Mechanical hyperalgesia and allodynia incidence varies considerably amongst neuropathic pain patients. This study explored whether sensory or psychological factors associate with mechanical hyperalgesia and brush allodynia in a human experimental model.

METHODS

Sixty-six healthy volunteers (29 male) completed psychological questionnaires and participated in two quantitative sensory testing (QST) sessions. Warmth detection threshold (WDT), heat pain threshold (HPT) and suprathreshold mechanical pain (STMP) ratings were measured before exposure to a capsaicin-heat pain model (C-HP). After C-HP exposure, brush allodynia and STMP were measured in one session, whilst mechanical hyperalgesia was measured in another session.

RESULTS

WDT and HPT measured in sessions separated by 1 month demonstrated significant but moderate levels of reliability (WDT: ICC = 0.5, 95%CI [0.28, 0.77]; HPT: ICC = 0.62, 95%CI [0.40, 0.77]). Brush allodynia associated with lower WDT (z = -3.06, p = 0.002; ϕ = 0.27). Those with allodynia showed greater hyperalgesia intensity (F = 7.044, p = 0.010, η_p ²  = 0.107) and area (F = 9.319, p = 0.004, η_p ²  = 0.163) than those without allodynia. No psychological self-report measures were significantly different between allodynic and nonallodynic groups. Intensity of hyperalgesia in response to lighter mechanical stimuli was associated with lower HPT, higher STMP ratings and higher Pain Sensitivity Questionnaire scores at baseline. Hyperalgesia to heavier probe stimuli associated with state anxiety and to a lesser extent somatic awareness. Hyperalgesic area associated with lower baseline HPT and higher STMP ratings. Hyperalgesic area was not correlated with allodynic area across individuals.

CONCLUSIONS

These findings support research in neuropathic pain patients and human experimental models that peripheral sensory input and individual sensibility are related to development of mechanical allodynia and hyperalgesia during central sensitization, whilst psychological factors play a lesser role.

SIGNIFICANCE

We evaluated differential relationships of psychological and perceptual sensitivity to the development of capsaicin-induced mechanical allodynia and hyperalgesia. Fifty percent of healthy volunteers failed to develop mechanical allodynia. Baseline pain sensitivity was greater in those developing allodynia and was related to the magnitude and area of hyperalgesia. State psychological factors, whilst unrelated to allodynia, were related to mechanical hyperalgesia. This supports that the intensity of peripheral sensory input and individual sensibility are related to development of mechanical allodynia and hyperalgesia during central sensitization, whilst psychological factors play a lesser role.

[Chronic postoperative pain]

The problem of chronic postoperative pain has been actualized for the last 20 years all over the world. At least 10-40% of patients suffer from chronic pain after surgery. This review is devoted to the current state of the problem of chronic postoperative pain, risk factors and prediction of chronic pain. The authors emphasize the need for interdisciplinary approach to prevention and treatment of this adverse event.

[Perioperative analgesia with nonopioid analgesics : Joint interdisciplinary consensus-based recommendations of the German Pain Society, the German Society of Anaesthesiology and Intensive Care Medicine and the German Society of Surgery]

Hintergrund

Nichtopioidanalgetika werden bei vielen Patienten zur perioperativen Analgesie eingesetzt. Zu einigen praktischen Fragen beim Einsatz von Nichtopioidanalgetika liegen z. T. nur wenig Informationen aus Studien vor, und in Krankenhäusern existieren häufig keine Konzepte zum Vorgehen, z. B. zur Patientenaufklärung und zum Zeitpunkt der perioperativen Gabe.

Methodik

Eine Expertengruppe der beteiligten Fachgesellschaften hat konsensbasierte Empfehlungen zum perioperativen Einsatz von Nichtopioidanalgetika erarbeitet und in einem strukturierten formalen Konsensusprozess verabschiedet.

Ergebnisse

Die Arbeitsgruppe stimmt überein, dass Nichtopioidanalgetika Bestandteil eines perioperativen multimodalen Analgesiekonzepts sein sollen und Patienten präoperativ über Nutzen, Risiken und alternative Behandlungsmöglichkeiten aufgeklärt werden sollen. Die präoperative Patienteninformation und -edukation soll auch eine Schmerz- und Analgetikaanamnese umfassen und Patienten mit Risikofaktoren für starke Schmerzen und eine Schmerzchronifizierung sollen identifiziert werden. Unter Berücksichtigung von Kontraindikationen können Nichtopioidanalgetika abhängig von der Operationsdauer auch schon prä- oder intraoperativ gegeben werden, um nach Beendigung der Anästhesie ausreichende Plasmakonzentrationen zu erzielen. Nichtopioidanalgetika oder Kombinationen von (Nichtopioid‑)Analgetika sollen nur für einen begrenzten Zeitraum gegeben werden. Ein gemeinsam erarbeiteter abteilungsübergreifender Behandlungsstandard mit dem Nichtopioidanalgetikum erster Wahl, weiteren Therapieoptionen sowie adäquaten Dosierungen, ergänzt durch eingriffsspezifische Konzepte, soll schriftlich hinterlegt werden. Bei Entlassung aus dem Krankenhaus soll der nachbehandelnde Arzt zu perioperativ gegebenen und aktuell noch eingenommenen Analgetika schriftliche Informationen erhalten. Patienten sollen zu möglichen Nebenwirkungen der Analgetika und ihrer Symptome, die auch nach Krankenhausentlassung auftreten können, und die befristete Einnahmedauer informiert werden.

Schlussfolgerung

Die Anwendung von Nichtopioidanalgetika soll als Bestandteil eines perioperativen multimodalen Analgesiekonzepts mit klaren Vorgaben zu Indikationen, Kontraindikationen, Dosierungen und Behandlungsdauer in einem abteilungsübergreifenden Behandlungsstandard schriftlich hinterlegt werden.

Zusatzmaterial online

Die Offenlegung von Interessen ist in der Online-Version dieses Artikels (10.1007/s00104-021-01421-w) enthalten.

Psychological Factors Are Associated with Pain at All Time Frames After Breast Cancer Surgery: A Systematic Review with Meta-Analyses

OBJECTIVE

This systematic review aimed to 1) assess associations between psychological factors and pain after breast cancer (BC) treatment and 2) determine which preoperative psychological factors predicted pain in the acute, subacute, and chronic time frames after BC surgery.

DESIGN

A systematic review with meta-analysis.

SUBJECTS

Women with early-stage BC.

METHODS

The Medline, EMBASE, CINAHL, and Web of Science databases were searched between 1990 and January 2019. Studies that evaluated psychological factors and pain after surgery for early-stage BC were included. Associations between psychological factors and pain, from early after surgery to >12 months after surgery, were extracted. Effect size correlations (r equivalents) were calculated and pooled by using random-effects meta-analysis models.

RESULTS

Of 4,137 studies, 47 were included (n = 15,987 participants; 26 studies ≤12 months after surgery and 22 studies >12 months after surgery). The majority of the studies had low to moderate risk of bias. Higher preoperative anxiety and depression were weak but significant predictors of pain at all time points up to 12 months (r equivalent: 0.15-0.22). Higher preoperative pain catastrophizing and distress were also weak but significant predictors of pain during the acute (0-7 days) and chronic (3-12 months) periods (r equivalent: 0.10-0.20). For the period >12 months after surgery, weak but significant cross-sectional associations with pain were identified for anxiety, depression, pain catastrophizing, and distress (r equivalents: 0.15, 0.17, 0.25, 0.14, respectively).

CONCLUSION

Significant pooled effect size correlations between psychological factors and pain were identified across all time frames. Though weak, these associations should encourage assessment of key psychological factors during preoperative screening and pain assessments at all postoperative time frames.

Challenges and opportunities in translational pain research - An opinion paper of the working group on translational pain research of the European pain federation (EFIC)

For decades, basic research on the underlying mechanisms of nociception has held promise to translate into efficacious treatments for patients with pain. Despite great improvement in the understanding of pain physiology and pathophysiology, translation to novel, effective treatments for acute and chronic pain has however been limited, and they remain an unmet medical need. In this opinion paper bringing together pain researchers from very different disciplines, the opportunities and challenges of translational pain research are discussed. The many factors that may prevent the successful translation of bench observations into useful and effective clinical applications are reviewed, including interspecies differences, limited validity of currently available preclinical disease models of pain, and limitations of currently used methods to assess nociception and pain in non-human and human models of pain. Many paths are explored to address these issues, including the backward translation of observations made in patients and human volunteers into new disease models that are more clinically relevant, improved generalization by taking into account age and sex differences, and the integration of psychobiology into translational pain research. Finally, it is argued that preclinical and clinical stages of developing new treatments for pain can be improved by better preclinical models of pathological pain conditions alongside revised methods to assess treatment-induced effects on nociception in human and non-human animals. Significance: For decades, basic research of the underlying mechanisms of nociception has held promise to translate into efficacious treatments for patients with pain. Despite great improvement in the understanding of pain physiology and pathophysiology, translation to novel, effective treatments for acute and chronic pain has however been limited, and they remain an unmet medical need.

[Prediction and prevention of chronic postoperative pain]

Chronic postoperative pain has been identified as a major medical and socioeconomic problem. A prevention of the chronification processes is potentially possible and preventive treatment could start early (e.g. preoperatively). So far, however, evidence for the effectiveness of preventive strategies is basically low. Important reasons for this dilemma are the lack of appropriate risk assessment as well as effective and mechanism-based preventive (procedure-sepcific) strategies for the chronification process, a lack of stratification of treatment approaches and a so far barely investigated combination of various treatment approaches. In this review article recent findings on the appropriate identification of patients at risk for developing postoperative chronic pain are presented, predictive models for the valid estimation of the individual risk of patients are assessed and studies on pharmaceutical and regional analgesia techniques influencing the pain chronification process are discussed. As a chronification process is, however, extremely complex and dynamic and also necessitates adaptation of the prevention during the course of the process, only combinations of treatment, interdisciplinary and if necessary even longer term approaches might be successful. Future studies are needed to address with which preventive treatment strategies and in which patients chronic pain after surgery can effectively be prevented.

Acute pain after breast surgery and reconstruction: A two-institution study of surgical factors influencing short-term pain outcomes

BACKGROUND AND OBJECTIVES

Acute postoperative pain following surgery is known to be associated with chronic pain development and lower quality of life. We sought to analyze the relationship between differing breast cancer excisional procedures, reconstruction, and short-term pain outcomes.

METHODS

Women undergoing breast cancer excisional procedures with or without reconstruction at two systems: an academic hospital (AH) and Veterans Health Administration (VHA) were included. Average pain scores at the time of discharge and at 30-day follow-up were analyzed across demographic and clinical characteristics. Linear mixed effects modeling was used to assess the relationship between patient/clinical characteristics and interval pain scores with a random slope to account for differences in baseline pain.

RESULTS

Our study included 1402 patients at AH and 1435 at VHA, of which 426 AH and 165 patients with VHA underwent reconstruction. Pain scores improved over time and were found to be highest at discharge. Time at discharge, 30-day follow-up, and preoperative opioid use were the strongest predictors of high pain scores. Younger age and longer length of stay were independently associated with worse pain scores.

CONCLUSIONS

Younger age, preoperative opioid use, and longer length of stay were associated with higher levels of postoperative pain across both sites.

Predicting poor postoperative acute pain outcome in adults: an international, multicentre database analysis of risk factors in 50,005 patients

Supplemental Digital Content is Available in the Text.

Eight risk factors were identified in a large international database. Patients with 3 or more risk factors are at higher risk for poor pain outcome.

Background:

The aim of this study was to determine simple risk factors for severe pain intensity (≥7 points on a numeric rating scale [NRS]), to analyse their relation to other patient-reported outcome measures and to develop a simple prediction model.

Methods:

We used data from 50,005 patients from the PAIN-OUT project. Within a first data set (n = 33,667), relevant risk factors were identified by logistic binary regression analysis, assessed for additional patient-reported outcome measures beyond pain intensity and summed up for developing a simple risk score. Finally, sum of factors was plotted against postoperative pain outcomes within a validation data set (n = 16,338).

Results:

Odds ratios (OR) for the following risk factors were identified: younger age (<54 years, OR: 1.277), preoperative chronic pain at the site of surgery (OR: 1.195), female sex (OR: 1.433), duration of surgery (>90 minutes, OR: 1.308), preoperative opioid intake (OR: 1.250), feeling anxious (OR: 1.239) and feeling helpless due to pain (OR: 1.198), and the country of the recruiting centre (OR: 1.919). Patients with ≥3 risk factors had more severe pain intensity scores, spent a longer time in severe pain, and wished to have received more pain treatment (P < 0.001). A simple risk score was created with 4 risk factors showing a moderate prediction level.

Conclusions:

Patients with ≥3 risk factors are at higher risk for poor postoperative acute pain outcome after surgery. Future studies using this score might show that preventive strategies might decrease pain intensity, pain-related postoperative dysfunction, and the development of chronic pain.

AAAPT Diagnostic Criteria for Acute Pain Following Breast Surgery

Acute pain after breast surgery decreases the quality of life of cancer survivors. Previous studies using a variety of definitions and methods report prevalence rates between 10% and 80%, which suggests the need for a comprehensive framework that can be used to guide assessment of acute pain and pain-related outcomes after breast surgery. A multidisciplinary task force with clinical and research expertise performed a focused review and synthesis and applied the 5 dimensional framework of the AAAPT (Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks [ACTTION], American Academy of Pain Medicine [AAPM], American Pain Society [APS] Pain Taxonomy) to acute pain after breast surgery. Application of the AAAPT taxonomy yielded the following: 1) Core Criteria: Location, timing, severity, and impact of breast surgery pain were defined; 2) Common Features: Character and expected trajectories were established in relevant surgical subgroups, and common pain assessment tools for acute breast surgery pain identified; 3) Modulating Factors: Biological, psychological, and social factors that modulate interindividual variability were delineated; 4) Impact/Functional Consequences: Domains of impact were outlined and defined; 5) Neurobiologic Mechanisms: Putative mechanisms were specified ranging from nerve injury, inflammation, peripheral and central sensitization, to affective and social processing of pain. PERSPECTIVE: The AAAPT provides a framework to define and guide improved assessment of acute pain after breast surgery, which will enhance generalizability of results across studies and facilitate meta-analyses and studies of interindividual variation, and underlying mechanism. It will allow researchers and clinicians to better compare between treatments, across institutions, and with other types of acute pain.

Benefit of regional anaesthesia on postoperative pain following mastectomy: the influence of catastrophising

BACKGROUND

Previous studies suggest that truncal regional anaesthesia (TRA), including techniques such as paravertebral block, may contribute significantly to analgesia after mastectomy. However, the severity and impact of postoperative pain varies markedly amongst individuals, making the identification of patients who would benefit most from TRA a potentially important step toward personalised perioperative care.

METHODS

In this prospective observational study, mastectomy patients (n=122) were recruited and systematically assessed for psychosocial characteristics including pain catastrophising before surgery, and either received preoperative TRA (n=57) or no block (n=65).

RESULTS

Age, baseline pain, and psychosocial traits did not differ between these groups. TRA was associated with lower overall pain scores and opioid consumption perioperatively, with a larger proportion of patients without block (50% vs 28%) reporting moderate-severe pain (more than three/10) on the day of surgery. Mixed model analysis of variance revealed a significant interaction between catastrophising and TRA, such that amongst patients with high baseline catastrophising, TRA was associated with substantially lower pain severity score (58% lower), while amongst patients with low baseline catastrophising, TRA was associated with only 18% lower pain severity. At 2 weeks, this interaction between baseline catastrophising and TRA was also observed when examining surgical pain burden, with higher baseline catastrophising patients who had received TRA reporting lower pain and less frequent opioid use (40% vs 70% of patients).

CONCLUSIONS

TRA provided immediate analgesic benefit for patients undergoing mastectomy on the day of surgery, but this effect appeared more pronounced and sustained amongst patients with higher baseline catastrophising.

CLINICAL TRIAL REGISTRATION

NCT02329574.

The relationship between sensitivity to pain and conditioned pain modulation in healthy people

BACKGROUND

The relationship between sensitivity to pain and conditioned pain modulation (CPM) - a paradigm reflecting the activity of the endogenous descending analgesic system - is still unclear. This study aimed at investigating CPM magnitude in two distinct subgroups of healthy subjects, presenting low vs. high sensitivity to pain (LSP vs. HSP, respectively), by employing two different thermal paradigms of CPM.

METHOD

Ninety-five healthy subjects (out of 293 tested) were identified as LSP (n = 48) or HSP (n = 47) according to their tolerance time to noxious cold stimulation (Cold Pressor Test, 1 °C). All subjects were exposed to two different paradigms of CPM: 1) Fixed temperature 'test-pain' (TP) where phasic, fixed painful heat stimuli of 47 °C were administered before and during a prolonged 'conditioning stimulus' (cold water at 12 °C for 30 s); and 2) Individually based 'pain-60' where TP was determined as the temperature that induced pain at a magnitude of 60 on a 0-100 rating scale (with the same conditioning stimulus).

RESULT

Using both thermal paradigms, LSP subjects showed decreased CPM magnitudes in comparison to HSP (p < 0.0001 in both paradigms). Within each group, no differences in the magnitudes of CPM were found between the two paradigms.

CONCLUSION

These findings show that regardless of the thermal CPM paradigm employed, healthy individuals exhibiting low sensitivity to pain have a low pain inhibition profile and vice-versa. It is suggested that in healthy subjects, pain sensitivity predisposes the magnitude of CPM and not the other way around.

Mechanisms of acute and chronic pain after surgery: update from findings in experimental animal models

PURPOSE OF REVIEW

Management of postoperative pain is still a major issue and relevant mechanisms need to be investigated. In preclinical research, substantial progress has been made, for example, by establishing specific rodent models of postoperative pain. By reviewing most recent preclinical studies in animals related to postoperative, incisional pain, we outline the currently available surgical-related pain models, discuss assessment methods for pain-relevant behavior and their shortcomings to reflect the clinical situation, delineate some novel clinical-relevant mechanisms for postoperative pain, and point toward future needs.

RECENT FINDINGS

Since the development of the first rodent model of postoperative, incisional pain almost 20 years ago, numerous variations and some procedure-specific models have been emerged including some conceivably relevant for investigating prolonged, chronic pain after surgery. Many mechanisms have been investigated by using these models; most recent studies focussed on endogenous descending inhibition and opioid-induced hyperalgesia. However, surgical models beyond the classical incision model have so far been used only in exceptional cases, and clinical relevant behavioral pain assays are still rarely utilized.

SUMMARY

Pathophysiological mechanisms of pain after surgery are increasingly discovered, but utilization of pain behavior assays are only sparsely able to reflect clinical-relevant aspects of acute and chronic postoperative pain in patients.

Risk factors for severe acute pain and persistent pain after surgery for breast cancer: a prospective observational study

Background and objectives

There are few prospective studies providing comprehensive assessment of risk factors for acute and persistent pain after breast surgery. This prospective observational study assessed patient-related, perioperative, and genetic risk factors for severe acute pain and persistent pain following breast cancer surgery.

Methods

Women presenting for elective breast cancer surgery completed State Trait Anxiety Inventory, Beck Depression Inventory, and Pain Catastrophizing Scale questionnaires preoperatively. Diffuse noxious inhibitory control and mechanical temporal summation were assessed. A blood sample was obtained for genetic analysis. Analgesic consumption and pain scores were collected in the post-anesthesia care unit, and at 24 and 72 hours. Patients were contacted at 1, 3, 6, and 12 months to assess persistent pain. Primary outcome was maximum acute pain score in first 72 hours and secondary outcome was persistent pain.

Results

One hundred twenty-four patients were included in analysis. Increased duration of surgery, surgeon, and higher pain catastrophizing scores were associated with increased severity of acute pain, while preoperative radiotherapy was associated with reduced severity. Persistent pain was reported by 57.3% of patients. Postdischarge chemotherapy (OR 2.52, 95% CI 1.13 to 5.82), postdischarge radiation (OR 3.39, 95% CI 1.24 to 10.41), severe acute pain (OR 5.39, 95% CI 2.03 to 15.54), and moderate acute pain (OR 5.31, 95% CI 1.99 to 15.30) were associated with increased likelihood of persistent pain.

Conclusions

Increased duration of surgery, higher pain catastrophizing score, and surgeon were associated with increased severity of acute pain. Preoperative radiation was associated with lower acute pain scores. Postsurgery radiation, chemotherapy, and severity of acute pain were associated with increased likelihood of persistent pain.

Trial registration

NCT03307525.

Comparisons of Conditioned Pain Modulation and Physical Activity Between Hispanic and Non-Hispanic White Adults

It is well-documented that adults of racial/ethnic minorities experience pain more frequently and suffer from more severe pain compared to non-Hispanic White (NHW) adults. These observations are consistent with laboratory findings that adults of racial/ethnic minorities show increased sensitivity to laboratory pain stimuli compared to NHW adults. Research generally shows that central pain inhibitory processing, as quantified using conditioned pain modulation (CPM), serves as a risk factor of clinical pain. Currently, racial/ethnic differences in CPM are poorly understood, and research suggests that physical activity (PA) may help understand potential racial/ethnic differences in CPM. However, very little is known regarding CPM in Hispanic compared to NHW adults. Therefore, the present study compared CPM and PA between Hispanic and NHW adults. Twenty-one young, healthy Hispanic and 21 NHW adults completed validated questionnaires to assess PA, pain catastrophizing, and dispositional optimism. The participants then completed the CPM test to quantify changes in pain ratings to electrical stimuli delivered to the ankle during concurrent application of pressure pain applied to the finger compared to baseline. Results indicated that Hispanic and NHW adults exhibited comparable CPM responses and PA levels, along with similar levels of pain catastrophizing and dispositional optimism (p > 0.05). These results suggest that young, healthy Hispanic and NHW adults may possess a similar risk of clinical pain when they are comparable in PA, pain catastrophizing, and dispositional optimism. More research is needed to explore the role of PA in racial/ethnic disparities in clinical pain and central pain inhibitory processing.

Preoperative Psychosocial and Psychophysical Phenotypes as Predictors of Acute Pain Outcomes After Breast Surgery

The severity and impact of acute pain after breast surgery varies markedly among individuals, underlining the importance of comprehensively identifying specific risk factors, including psychosocial and psychophysical traits. In this prospective observational study, women (n = 234) undergoing breast-conserving surgery, mastectomy, or mastectomy with reconstruction completed a brief bedside quantitative sensory testing battery, along with measures of psychosocial characteristics. Postoperative pain severity, impact, and opioid use at 2 weeks were assessed using Brief Pain Inventory and procedure-specific breast cancer pain questionnaires. Moderate-severe average pain (>3/10) was reported by 29% of patients at 2 weeks. Regression analysis of pain outcomes revealed that pain severity was independently predicted by axillary dissection, pre-surgical pain, temporal summation of pain (TSP), (-)positive affect, and behavioral coping style. Pain impact was predicted by age, education, axillary dissection, reconstruction, but also by negative affect and depression scores. Lastly, opioid use was predicted by age, education, axillary dissection, reconstruction, TSP, and reinterpreting coping style. Our findings suggest that, individuals with certain phenotypic characteristics, including high TSP and negative affect, may be at greater risk of significant pain and continued opioid use at 2 weeks after surgery, independent of known surgical risk factors. PERSPECTIVE: We measured differences in the psychosocial and psychophysical processing of pain amongst patients before breast surgery using simple validated questionnaires and brief quantitative sensory testing. Independent of younger age and procedural extent (axillary surgery and reconstruction), affect and greater temporal summation of pain predicted acute postoperative pain and opioid use.

Association between self-perceived pain sensitivity and pain intensity after cardiac surgery

Background and purpose

Cardiac surgical pain remains a clinical challenge affecting about 40% of individuals in the first six months post-cardiac surgery, and continues up to two years after surgery for about 15–20%. Self-perceived sensitivity to pain may help to identify individuals at risk for persistent cardiac surgical pain to optimize health care responses. The purpose of this study was to assess the relationship between self-perceived pain sensitivity assessed by the Pain Sensitivity Questionnaire (PSQ) and postoperative worst pain intensity up to 12 months after cardiac surgery. Sex differences in baseline characteristics and the PSQ scores were also assessed.

Methods

This study was performed among 416 individuals (23% women) scheduled for elective coronary artery bypass graft and/or valve surgery between March 2012 and September 2013. A secondary data-analysis was utilized to explore the relationship between preoperative PSQ scores and worst pain intensity rated preoperatively, across postoperative Days 1–4, at 2 weeks, and at 1, 3, 6, and 12 months post-surgery. Linear mixed model analyses were performed to estimate changes in pain intensity during 1-year follow-up.

Results

The mean (±standard deviation) PSQ-total score was 3.3±1.4, with similar scores in men and women. The PSQ-total score was significantly associated with higher worst pain intensity ratings adjusted for participant characteristics (p=0.001).

Conclusion

Use of the PSQ before surgery may predict cardiac surgical pain intensity. However, previous evidence is limited and not consistent, and more research is needed to substantiate our results.

Conditioned pain modulation identifies altered sensitivity in extremely preterm young adult males and females

BACKGROUND

Conditioned pain modulation is a potential biomarker for risk of persistent pain. As early-life experience can alter subsequent somatosensory processing and pain response, we evaluated conditioned pain modulation after extremely preterm birth.

METHODS

This observational study recruited extremely preterm (<26 weeks gestation; n=98) and term-born control (n=48) young adults (19-20 yr) from the longitudinal EPICure cohort. Pressure pain threshold (PPT; variable test stimulus lower leg) was measured before, during, and after a conditioning stimulus (contralateral hand immersion; 5°C water; 30 s). Questionnaires assessed current pain, medication use, anxiety, and pain catastrophising.

RESULTS

For participants tolerating conditioning, there were significant main effects of extremely preterm status, sex, and time on PPT during and after hand immersion. Inhibitory modulation was evoked in 64/98 extremely preterm (3, no change) and 38/48 term-born control (3, facilitation) subjects. The conditioned pain modulation effect (percentage change in PPT) did not differ between the extremely preterm and term-born control groups {53% [95% confidence interval (CI): 41-65] vs 57% [95% CI: 42-71]}. Reduced cold tolerance (<20 s) hampered conditioned pain modulation quantification in a higher proportion of extremely preterm participants [extremely preterm vs term-born control: 31/98 (32%) vs 7/48 (15%); P=0.03]. One-third of extremely preterm females withdrew the hand before parallel PPT (<15 s), and had lower baseline PPT than term-born control females [4.9 (95% CI: 4.8-5.1) vs 5.3 (95% CI: 5.1-5.5) ln kPa; P=0.02]. Higher anxiety, pain catastrophising, and medication use correlated with pain intensity, but not conditioned pain modulation effect.

CONCLUSIONS

Cold conditioning evoked inhibitory modulation in the majority of young adults and identified a subgroup of extremely preterm females with increased baseline sensitivity. Early-life experience and sex/gender should be considered when evaluating persistent pain risk with conditioned pain modulation.

Psychological factors as predictors of early postoperative pain after open nephrectomy

Purpose

There is an increasing interest in the identification of predictors for individual responses to analgesics and surgical pain. In this study, we aimed to determine psychological factors that might contribute to this response. We hence investigated patients undergoing a standardized surgical intervention (open nephrectomy).

Patients and methods

Between May 2014 and April 2015, we conducted a prospective observational cohort study. The following psychological tests were administered preoperatively: Mini-Mental State Examination, Amsterdam Preoperative Anxiety and Information Scale (APAIS), Hamilton Anxiety Rating Scale, Hamilton Depression Rating Scale, and Pain Catastrophizing Scale. The primary outcome, postoperative pain intensity (11-point numerical rating scale, [NRS]), was assessed in the “immediate early” (first 8 hours), “early” (12 and 24 hours), and “late early” periods (48 and 72 hours).

Results

A total of 196 patients were assessed, and 150 were finally included in the study. NRS scores improved from 4.9 (95% confidence interval [CI]: 4.7–5.1) in the “immediate early” to 3.1 (95% CI: 2.9–3.3) in the “early” and 2.3 (95% CI: 2.1–2.5) in the “late early” postoperative period. Most (87%) patients received intravenous opioids, while 13% received analgesics epidurally. Repeated measures analysis of variance indicated better pain management with epidural analgesia in the first two postoperative periods (F=15.01, p<0.00). Postoperative pain correlated strongly with analgesic strategy and preoperative psychological assessment. Multiple linear regression analysis showed “expected pain” was the only predictor in the “immediate early” phase, and “anxiety” was most important in the “early” postoperative period. In the “late early” phase, catastrophizing was the predominant predictor, alongside “preoperative analgesic usage” and “APAIS anxiety”.

Conclusion

After open nephrectomy, epidural analgesia conveys a clear advantage for pain management only within the first 24 hours. Moreover, as the psychological phenotype of patients changes distinctively in the first 72 postoperative hours, psychological variables increasingly determine pain intensity, even surpassing employed analgesic strategy as its main predictor.

Current methods and challenges for acute pain clinical trials

This article reviews current methods and challenges and provides recommendations for future design and conduct of clinical trials of interventions to treat acute pain.

Introduction:

The clinical setting of acute pain has provided some of the first approaches for the development of analgesic clinical trial methods.

Objectives:

This article reviews current methods and challenges and provides recommendations for future design and conduct of clinical trials of interventions to treat acute pain.

Conclusion:

Growing knowledge about important diverse patient factors as well as varying pain responses to different acute pain conditions and surgical procedures has highlighted several emerging needs for acute pain trials. These include development of early-phase trial designs that minimize variability and thereby enhance assay sensitivity, minimization of bias through blinding and randomization to treatment allocation, and measurement of clinically relevant outcomes such as movement-evoked pain. However, further improvements are needed, in particular for the development of trial methods that focus on treating complex patients at high risk of severe acute pain.