AAAPT: Assessment of the Acute Pain Trajectory

Prognostic clinical prediction models for acute post-surgical pain in adults: a systematic review

BACKGROUND

Acute post-surgical pain is managed inadequately in many patients undergoing surgery. Several prognostic risk prediction models have been developed to identify patients at high risk of developing moderate to severe acute post-surgical pain. The aim of this systematic review was to describe and evaluate the methodological conduct of these prediction models.

METHODS

We searched MEDLINE, EMBASE and CINAHL for studies of prognostic risk prediction models for acute post-surgical pain using predetermined criteria. Prediction model performance was evaluated according to discrimination and calibration. Adherence to TRIPOD guidelines was assessed. Risk of bias and applicability was independently assessed by two reviewers using the prediction model risk of bias assessment tool.

RESULTS

We included 14 studies reporting on 17 prediction models. The most common predictors identified in final prediction models included age; surgery type; sex or gender; anxiety or fear of surgery; pre-operative pain intensity; pre-operative analgesic use; pain catastrophising; and expected surgical incision size. Discrimination, measured by the area under receiver operating characteristic curves or c-statistic, ranged from 0.61 to 0.83. Calibration was only reported for seven models. The median (IQR [range]) overall adherence rate to TRIPOD items was 62 (53-66 [47-72])%. All prediction models were at high risk of bias.

CONCLUSIONS

Effective prediction models could support the prevention and treatment of acute post-surgical pain; however, existing models are at high risk of bias which may affect their reliability to inform practice. Consideration should be given to the goals, timing of intended use and desired outcomes of a prediction model before development.

Association between acute pain trajectory and patient-reported outcomes at 6-months following lumbar surgery for patients with lumbar degenerative disease

PURPOSE

To investigate the association between acute pain trajectory over one week and patient-reported outcomes (PRO) at 6-months following lumbar surgery in patients with lumbar degenerative disease (LDD).

METHODS

Two hundred and fifty-five subjects with LDD who received surgical treatment at our hospital between April 2019 and March 2022. Acute pain trajectory was measured using a pain trajectory calculator to determine an approximate line using the linear least squares method based on pain intensity on postoperative days 1, 3, 5, and 7. The pain trajectory-slope, which represents the change in postoperative pain intensity of the calculated approximation line, was evaluated as the main exposure for the present study. The PRO was assessed using the Oswestry Disability Index (ODI) measured at 6 ± 1 months postoperatively. Poor PRO scores in this study were defined using a threshold of an ODI of 22% or greater, which represents the patient acceptable symptomatic state after lumbar spine surgery. Multivariable logistic regression analysis including covariates was performed to investigate the association between pain trajectory-slope and PRO at 6-months following lumbar surgery.

RESULTS

In this study, 101 (39.6%) had poor PRO scores. Multivariable logistic regression analysis adjusted for covariates showed that pain trajectory-slope was associated with the poor PRO scores (odd ratios; 1.203, 95% confidence intervals; 1.130-1.288).

CONCLUSIONS

The results of this study show that acute pain trajectory is significantly associated with poor PRO scores 6-months after lumbar surgery. Patients with slower pain relief or worsening pain were associated with poor PRO scores.

Prospective Study of Preoperative Negative Affect and Postoperative Pain in Patients Undergoing Thoracic Surgery: The Moderating Role of Sex

Objective: Preoperative negative affect is a risk factor for worse postoperative pain, but research investigating this association among patients undergoing thoracic surgery is inconsistent. Additionally, female patients often report greater negative affect and postoperative pain than males. This prospective observational study investigated the association between preoperative negative affect and postoperative pain after thoracic surgery and whether this association differed by sex. Methods: Patients (n = 105) undergoing thoracic surgery completed preoperative assessments of pain and negative affect (PROMIS anxiety and depression short forms). Patients reported their daily worst pain over the first 7 postoperative days, and an index score of acute postoperative pain was created. Six months after surgery, a subsample of patients (n = 60) reported their worst pain. Results: Higher levels of preoperative anxiety (r = 0.25, p = 0.011) and depression (r = 0.20, p = 0.042) were associated with greater acute postoperative pain, but preoperative negative affect was not related to chronic postsurgical pain (anxiety: r = 0.19, p = 0.16; depression: r = -0.01, p = 0.94). Moderation analyses revealed that the associations between both preoperative anxiety (b = 0.12, 95% CI [0.04, 0.21], p = 0.004) and depression (b = 0.15, 95% CI [0.04, 0.26], p = 0.008) with acute postoperative pain were stronger among females than males. Similarly, the association between preoperative anxiety and chronic postsurgical pain was stronger among females (b = 0.11, 95% CI [0.02, 0.20], p = 0.022), but the association between preoperative depression and chronic pain did not differ based on sex (b = 0.13, 95% CI [-0.07, 0.34], p = 0.201]). Conclusions: Our findings suggest that negative affect may be especially important to the experience of pain following thoracic surgery among female patients, whose degree of preoperative anxiety may indicate vulnerability to progress to a chronic pain state. Preoperative interventions aimed at reducing negative affect and pain may be particularly useful among females with high negative affect before thoracic surgery.

Statistical modeling of acute and chronic pain patient-reported outcomes obtained from ecological momentary assessment

ABSTRACT

Ecological momentary assessment (EMA) allows for the collection of participant-reported outcomes (PROs), including pain, in the normal environment at high resolution and with reduced recall bias. Ecological momentary assessment is an important component in studies of pain, providing detailed information about the frequency, intensity, and degree of interference of individuals' pain. However, there is no universally agreed on standard for summarizing pain measures from repeated PRO assessment using EMA into a single, clinically meaningful measure of pain. Here, we quantify the accuracy of summaries (eg, mean and median) of pain outcomes obtained from EMA and the effect of thresholding these summaries to obtain binary clinical end points of chronic pain status (yes/no). Data applications and simulations indicate that binarizing empirical estimators (eg, sample mean, random intercept linear mixed model) can perform well. However, linear mixed-effect modeling estimators that account for the nonlinear relationship between average and variability of pain scores perform better for quantifying the true average pain and reduce estimation error by up to 50%, with larger improvements for individuals with more variable pain scores. We also show that binarizing pain scores (eg, <3 and ≥3) can lead to a substantial loss of statistical power (40%-50%). Thus, when examining pain outcomes using EMA, the use of linear mixed models using the entire scale (0-10) is superior to splitting the outcomes into 2 groups (<3 and ≥3) providing greater statistical power and sensitivity.

Beyond measurement: a deep dive into the commonly used pain scales for postoperative pain assessment

This review explores the essential methodologies for effective postoperative pain management, focusing on the need for thorough pain assessment tools, as underscored in various existing guidelines. Herein, the strengths and weaknesses of commonly used pain scales for postoperative pain-the Visual Analog Scale, Numeric Rating Scale, Verbal Rating Scale, and Faces Pain Scale-are evaluated, highlighting the importance of selecting appropriate assessment tools based on factors influencing their effectiveness in surgical contexts. By emphasizing the need to comprehend the minimal clinically important difference (MCID) for these scales in evaluating new analgesic interventions and monitoring pain trajectories over time, this review advocates recognizing the limitations of common pain scales to improve pain assessment strategies, ultimately enhancing postoperative pain management. Finally, five recommendations for pain assessment in research on postoperative pain are provided: first, selecting an appropriate pain scale tailored to the patient group, considering the strengths and weaknesses of each scale; second, simultaneously assessing the intensity of postoperative pain at rest and during movement; third, conducting evaluations at specific time points and monitoring trends over time; fourth, extending the focus beyond the intensity of postoperative pain to include its impact on postoperative functional recovery; and lastly, interpreting the findings while considering the MCID, ensuring that it is clinically significant for the chosen pain scale. These recommendations broaden our understanding of postoperative pain and provide insights that contribute to more effective pain management strategies, thereby enhancing patient care outcomes.

Ultrasound and magnetic resonance imaging-based investigation of the role of perfusion and oxygen availability in menstrual pain

BACKGROUND

The mechanisms responsible for menstrual pain are poorly understood. However, dynamic, noninvasive pelvic imaging of menstrual pain sufferers could aid in identifying therapeutic targets and testing novel treatments.

OBJECTIVE

To study the mechanisms responsible for menstrual pain, we analyzed ultrasonographic and complementary functional magnetic resonance imaging parameters in dysmenorrhea sufferers and pain-free controls under multiple conditions.

STUDY DESIGN

We performed functional magnetic resonance imaging on participants with and those without dysmenorrhea during menses and outside menses. To clarify whether regional changes in oxygen availability and perfusion occur, functional magnetic resonance imaging R2∗ measurements of the endometrium and myometrium were obtained. R2∗ measurements are calculated nuclear magnetic resonance relaxation rates sensitive to the paramagnetic properties of oxygenated and deoxygenated hemoglobin. We also compared parameters before and after an analgesic dose of naproxen sodium. In addition, we performed similar measurements with Doppler ultrasonography to identify if changes in uterine arterial velocity occurred during menstrual cramping in real time. Mixed model statistics were performed to account for within-subject effects across conditions. Corrections for multiple comparisons were made with a false discovery rate adjustment.

RESULTS

During menstruation, a notable increase in R2∗ values, indicative of tissue ischemia, was observed in both the myometrium (beta ± standard error of the mean, 15.74±2.29 s-1; P=.001; q=.002) and the endometrium (26.37±9.33 s-1; P=.005; q=.008) of participants who experienced dysmenorrhea. A similar increase was noted in the myometrium (28.89±2.85 s-1; P=.001; q=.002) and endometrium (75.50±2.57 s-1; P=.001; q=.003) of pain-free controls. Post hoc analyses revealed that the R2∗ values during menstruation were significantly higher among the pain-free controls (myometrium, P=.008; endometrium, P=.043). Although naproxen sodium increased the endometrial R2∗ values among participants with dysmenorrhea (48.29±15.78 s-1; P=.005; q=.008), it decreased myometrial R2∗ values among pain-free controls. The Doppler findings were consistent with the functional magnetic resonance imaging (-8.62±3.25 s-1; P=.008; q=.011). The pulsatility index (-0.42±0.14; P=.004; q=.004) and resistance index (-0.042±0.012; P=.001; q=.001) decreased during menses when compared with the measurements outside of menses, and the effects were significantly reversed by naproxen sodium. Naproxen sodium had the opposite effect in pain-free controls. There were no significant real-time changes in the pulsatility index, resistance index, peak systolic velocity, or minimum diastolic velocity during episodes of symptomatic menstrual cramping.

CONCLUSION

Functional magnetic resonance imaging and Doppler metrics suggest that participants with dysmenorrhea have better perfusion and oxygen availability than pain-free controls. Naproxen sodium's therapeutic mechanism is associated with relative reductions in uterine perfusion and oxygen availability. An opposite pharmacologic effect was observed in pain-free controls. During menstrual cramping, there is insufficient evidence of episodic impaired uterine perfusion. Thus, prostaglandins may have protective vasoconstrictive effects in pain-free controls and opposite effects in participants with dysmenorrhea.

Time Effect on Acute Postoperative Pain After Total Knee Replacement Surgery: An Exploratory Study Using the Experience Sampling Method

OBJECTIVES

Acute postoperative pain (APP) is the main cause of postoperative dissatisfaction; however, traditional methods of pain assessment provide limited insights into the dynamics and development of APP. This study used the experience sampling method to understand the dynamics of APP over time in relation to various patient factors.

MATERIALS AND METHODS

Forty patients scheduled to undergo total knee replacement surgery were recruited in this study. Following an initial assessment, a short report questionnaire was sent to the patients through 10 digital alerts per day to assess the pain levels during 2 preoperative and the first 6 postoperative days. The data were analyzed using multilevel regression, including random intercept and slope.

RESULTS

Thirty-two patients submitted the prespecified minimum of 30% of their short reports, yielding 1217 records. The analysis revealed significant ( P <0.001) linear and quadratic decreases in APP and a quadratic time effect. The lowest between-day and within-day pain levels were observed on postoperative day 4.8 and during the time slot 3.8 or ~19:15, respectively. Significant random intercepts and slopes were noted, indicating variations in the mean pain level between patients and a decrease in pain. None of the 10 patient factors had any confounding effect.

DISCUSSION

Using the experience sampling method data combined with multilevel analysis, we were able to evaluate the postoperative pain course while considering inter-individual differences in the baseline pain level and nonlinear pain course over time. The findings of this study could aid clinicians in personalizing the treatment for APP.

Editorial for the Special Issue: "Advances in Postoperative Pain Management and Chronic Postoperative Pain"

Acute and chronic pain are two completely distinct universes [...].

Profiles of adult people in a Spanish sample with chronic pain: Cluster analysis

AIM

To establish groups of people with chronic non-cancer pain according to the impairment caused by pain and to identify factors associated with the group with a higher level of impairment.

BACKGROUND

Knowing the profiles of people who suffer from chronic non-cancer pain could make it possible to direct their treatment and to detect associated risks.

DESIGN

A cross-sectional study.

METHODS

A sample of 395 people with chronic non-cancer pain was collected in Pain Units and Primary Healthcare Centres in southern Spain (January to March 2020). A cluster analysis was performed to divide the population into groups and a binary logistic regression model was established to determine factors associated with the group with a higher level of impairment.

RESULTS

Two groups were identified: lower level of impairment due to pain, characterized by being 45-65 years old, not medicated with opioids or anxiolytics, employed and with a mild level of impact on daily life; and higher level of impairment characterized by being older than 65 years old, medicated with opioids and anxiolytics, retired or on medical leave and with a severe impact on daily life. In addition, among women, being widowed, single or a smoker are risk factors for belonging to the group with a higher level of impairment; being smokers or consuming alcohol three or less times a week would be risk factors in men.

CONCLUSIONS

Age, chronic non-cancer pain impact on daily life, work situation and the consumption of opioid drugs and/or anxiolytics are factors that appear to influence the level of impairment due to chronic pain.

IMPACT

These findings could help detect impairment due to pain in its early stages, determining the specific needs of each person.

Early Postoperative Pain Trajectories after Posterolateral and Axillary Approaches to Thoracic Surgery: A Prospective Monocentric Observational Study

Less-invasive thoracotomies may reduce early postoperative pain. The aims of this study were to identify pain trajectories from postoperative days 0–5 after posterolateral and axillary thoracotomies and to identify potential factors related to the worst trajectory. Patients undergoing a posterolateral (92 patients) or axillary (89 patients) thoracotomy between July 2014 and November 2015 were analyzed in this prospective monocentric cohort study. The best-fitting model resulted in four pain trajectory groups: trajectory 1, the “worst”, with 29.8% of the patients with permanent significant pain; trajectory 2 with patients with low pain (32.6%); trajectory 3 with patients with a steep decrease in pain (22.7%); and trajectory 4 with patients with a steep increase (14.9%). According to a multinomial logistic model multivariable analysis, some predictive factors allow for differentiation between trajectory groups 1 and 2. Risk factors for permanent pain are the existence of preoperative pain (OR = 6.94, CI 95% (1.54–31.27)) and scar length (OR = 1.20 (1.05–1.38)). In contrast, ASA class III is a protective factor in group 1 (OR = 0.02 (0.001–0.52)). In conclusion, early postoperative pain can be characterized by four trajectories and preoperative pain is a major factor for the worst trajectory of early postoperative pain.

A Brief Measure Assessing Adolescents' Daily In-Hospital Function Predicts Pain and Health Outcomes at Home After Major Surgery

OBJECTIVE

Pain-related function, an important component of pain assessment, is not systematically assessed in the hospital in part because of a lack of clinically meaningful measures of pain-related function. This prospective cohort study examined whether adolescents' pain-related function during hospitalization, measured daily with the Youth Acute Pain Functional Ability Questionnaire (YAPFAQ) is associated with pain and health-related quality of life (HRQOL) 2 weeks following surgery.

DESIGN

Adolescents undergoing major musculoskeletal surgery (N = 93) completed YAPFAQ (11 items) daily for up to three days in-hospital following surgery. Adolescents self-reported health-related quality of life on the pediatric quality of life inventory and pain intensity on a NRS at baseline (pre-surgery) and two-weeks following surgery. Regression models examined mean YAPFAQ and YAPFAQ rate of change as predictors of two-week outcomes, adjusting for sex, surgery type, and baseline pain/HRQOL.

RESULTS

Higher mean YAPFAQ scores (poorer function) were associated with higher pain intensity (β  =  0.2, p = 0.04) and poorer HRQOL (β = -0.3, p = 0.01) at home 2 weeks following surgery. YAPFAQ rate of change was not associated with 2-week outcomes.

CONCLUSIONS

Implementation of the YAPFAQ with in-hospital assessments to measure pain-related function will allow more comprehensive pain assessment. In-hospital YAPFAQ scores can predict important postsurgical outcomes at home and inform post-hospital care.

PERSPECTIVE

This article provides validation of a measure of pediatric pain-related function, the Youth Acute Pain Functional Ability Questionnaire (YAPFAQ) to predict important post-hospital outcomes after surgery.

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).