Pain Catastrophizing, Response to Experimental Heat Stimuli, and Post–Cesarean Section Pain

An Innovative EEG-Based Pain Identification and Quantification: A Pilot Study

OBJECTIVE

The present pilot study aimed to propose an innovative scale-independent measure based on electroencephalographic (EEG) signals for the identification and quantification of the magnitude of chronic pain.

METHODS

EEG data were collected from three groups of participants at rest: seven healthy participants with pain, 15 healthy participants submitted to thermal pain, and 66 participants living with chronic pain. Every 30 s, the pain intensity score felt by the participant was also recorded. Electrodes positioned in the contralateral motor region were of interest. After EEG preprocessing, a complex analytical signal was obtained using Hilbert transform, and the upper envelope of the EEG signal was extracted. The average coefficient of variation of the upper envelope of the signal was then calculated for the beta (13-30 Hz) band and proposed as a new EEG-based indicator, namely Piqβ, to identify and quantify pain.

MAIN RESULTS

The main results are as follows: (1) A Piqβ threshold at 10%, that is, Piqβ ≥ 10%, indicates the presence of pain, and (2) the higher the Piqβ (%), the higher the extent of pain.

CONCLUSIONS

This finding indicates that Piqβ can objectively identify and quantify pain in a population living with chronic pain. This new EEG-based indicator can be used for objective pain assessment based on the neurophysiological body response to pain.

SIGNIFICANCE

Objective pain assessment is a valuable decision-making aid and an important contribution to pain management and monitoring.

Brief Assessment of Patient Phenotype to Explain Variability in Postsurgical Pain and Opioid Consumption after Cesarean Delivery: Performance of a Novel Brief Questionnaire Compared to Long Questionnaires

BACKGROUND

Understanding factors that explain why some women experience greater postoperative pain and consume more opioids after cesarean delivery is crucial to building an evidence base for personalized prevention. Comprehensive psychosocial assessment with validated questionnaires in the preoperative period can be time-consuming. A three-item questionnaire has shown promise as a simpler tool to be integrated into clinical practice, but its brevity may limit the ability to explain heterogeneity in psychosocial pain modulators among individuals. This study compared the explanatory ability of three models: (1) the 3-item questionnaire, (2) a 58-item questionnaire (long) including validated questionnaires (e.g., Brief Pain Inventory, Patient Reported Outcome Measurement Information System [PROMIS]) plus the 3-item questionnaire, and (3) a novel 19-item questionnaire (brief) assessing several psychosocial factors plus the 3-item questionnaire. Additionally, this study explored the utility of adding a pragmatic quantitative sensory test to models.

METHODS

In this prospective, observational study, 545 women undergoing cesarean delivery completed questionnaires presurgery. Pain during local anesthetic skin wheal before spinal placement served as a pragmatic quantitative sensory test. Postoperatively, pain and opioid consumption were assessed. Linear regression analysis assessed model fit and the association of model items with pain and opioid consumption during the 48 h after surgery.

RESULTS

A modest amount of variability was explained by each of the three models for postoperative pain and opioid consumption. Both the brief and long questionnaire models performed better than the three-item questionnaire but were themselves statistically indistinguishable. Items that were independently associated with pain and opioid consumption included anticipated postsurgical pain medication requirement, surgical anxiety, poor sleep, pre-existing pain, and catastrophic thinking about pain. The quantitative sensory test was itself independently associated with pain across models but only modestly improved models for postoperative pain.

CONCLUSIONS

The brief questionnaire may be more clinically feasible than longer validated questionnaires, while still performing better and integrating a more comprehensive psychosocial assessment than the three-item questionnaire.

EDITOR’S PERSPECTIVE

Contribution of Hypersensitivity to Postureteroscopy Ureteral Stent Pain: Findings From Study to Enhance Understanding of Stent-associated Symptoms

OBJECTIVE

To examine the relationships between preoperative hypersensitivity to pain and central sensitization, and postoperative ureteral stent pain after ureteroscopy (URS) for urinary stones.

METHODS

Adults enrolled in the STudy to Enhance uNderstanding of sTent-associated Symptoms (STENTS) underwent quantitative sensory testing (QST) prior to URS and stent placement. Hypersensitivity to mechanical pain was assessed using a pressure algometer. Participants rated their pain intensity to pressure applied to the ipsilateral flank area and lower abdominal quadrant on the side of planned stent placement, and the contralateral forearm (control). Pressure pain thresholds were also assessed. Central sensitization was assessed by applying a pointed stimulator (pinprick) and calculating the temporal summation. Postoperative stent pain intensity and interference were assessed using PROMIS questionnaires. Data were analyzed using repeated-measures mixed-effects linear models.

RESULTS

Among the 412 participants, the median age was 54.0years, and 46% were female. Higher preoperative pain ratings to 2 kg and 4 kg mechanical pressure to the ipsilateral flank and abdominal areas were associated with higher postoperative stent pain intensity with the stent in situ. Greater degree of central sensitization preoperatively, manifesting as higher temporal summation, was associated with higher postoperative pain intensity. Factors associated with preoperative hypersensitivity on QST included female sex, presence of chronic pain conditions, widespread pain, and depression.

CONCLUSION

Hypersensitivity to pain and central sensitization preoperatively was associated with postoperative ureteral stent pain, suggesting a physiologic basis for stent symptom variation. QST may identify patients more likely to develop stent pain after URS and could inform selection for preventive and interventional strategies.

The Predictive Value of Cold Pack Test for Pain After Third Molar Surgery

BACKGROUND

Early identification of patients who are prone to postoperative pain may provide individualization of postoperative analgesia strategies.

PURPOSE

The aim of the study was to investigate whether the cold pack test is associated with postoperative pain levels after mandibular third molar surgery.

STUDY DESIGN, SETTING, SAMPLE

This prospective cohort study included healthy male patients admitted to Department of Oral and Maxillofacial Surgery of a tertiary health-care center between June 2022 and December 2022 and scheduled for lower third molar extraction. Those who had used any analgesic within the past 10 days or had a history of intolerance/allergy to analgesics were excluded.

PREDICTOR VARIABLE

The primary predictor variable was pain tolerance, measured using the endurance test score. Subjects were grouped into two categories, low tolerance test score (withdrew the hand from the cold pack in <240 seconds) and high tolerance test score (maintained the hand on the cold pack for 240 seconds).

MAIN OUTCOME VARIABLES

The primary outcome variable was pain measured by the patients from 0 to 10 with the visual analog scale, and the secondary outcome variables were the amount of ibuprofen and paracetamol consumed in the postoperative period. Pain measurements and ibuprofen consumption were recorded at 0-2, 8, 16, 24, 32, 40, 48, 56, 64, 72, 80, 88, and 96 hours (0-2 interval of the first 2 hours immediately after surgery).

COVARIATES

Age, classification and position of mandibular third molar were utilized as covariates.

ANALYSES

The relationship between pain tolerance and postoperative pain was analyzed using the Mann-Whitney U test and the Fisher exact test. Statistical analysis was performed using the SPSS version 28.0 software.

RESULTS

A total of 30 male patients with a mean age of 22.5 ± 4.8 years were included in our study. In the group with low pain tolerance, the pain scores at the first 2 hours, 32, and 48 hours after the operation (4.55 ± 3.59, 2.91 ± 2.59, 2.91 ± 2.43, respectively) were found to be significantly higher than the group with high pain tolerance (2.00 ± 2.67, 0.95 ± 1.68, 0.95 ± 1.39, respectively) (P < .05). In the first 2 hours after the operation, the amount of ibuprofen consumed was also significantly higher in the group with low pain tolerance compared to the other group, and 81.8% of this group felt the need to consume ibuprofen (P < .05).

CONCLUSIONS AND RELEVANCE

The cold pack test, a more practical version of quantitative sensory testing, is useful in identifying male patients at risk of developing greater pain after third molar surgery. It can be helpful to provide effective analgesia in male patients with different pain tolerance thresholds.

Preoperative pain sensitivity predicts postoperative pain severity and analgesics requirement in lumbar fusion surgery - a prospective observational study

BACKGROUND CONTENT

The goal of postoperative pain management is to facilitate the patient's return to normal activity and decrease the detrimental effects of acute postsurgical pain. In order to provide more tailored and successful pain treatment, it is necessary to identify individuals who are at a high risk of experiencing severe postoperative pain. The most precise way to assess pain sensitivity is by determining the pressure pain threshold and heat pain threshold by objective methods using a digital algometer and neurotouch respectively.

PURPOSE

The primary aim of the study is to assess the preoperative pain threshold and its influence on postoperative pain severity and analgesics requirements in patients undergoing lumbar fusion surgeries.

STUDY DESIGN

Prospective, observational study.

PATIENT SAMPLE

Sixty patients requiring a single-level lumbar fusion surgery.

OUTCOME MEASURES

Postoperative pain intensity and the amount of postoperative analgesics consumption.

METHODS

In our patients, preoperative pain sensitivity was assessed by pressure pain threshold measurements with the help of a digital algometer, and heat pain threshold using a neurotouch instrument. In addition, pain sensitivity questionnaires (PSQ) were used in all our patients to determine pain sensitivity. Preoperative psychosocial and functional assessments were performed by Hospital anxiety-depression scores (HADS), and Oswestry disability index (ODI) respectively. Preoperative visual analog scale (VAS) score was determined at three instances of needle prick (phlebotomy, glucometer blood sugar, and intradermal antibiotic test dose) and during the range of movements of the lumbar spine region. Postoperative VAS score and postoperative breakthrough analgesic requirements were recorded in all of these patients from day 0 to day 3.

RESULTS

The average age of the patients was 51.11±13.467 years and 70% were females. Females had lower mean algometry values (72.14±7.56) compared to males (77.34±6.33). Patients with higher HADS (p<.0016), higher PSQ (p<.001), higher ODI scores(p<.001), and female gender significantly correlated with a lower algometer average indicating high pain sensitivity. Patients with lower preoperative VAS scores and with higher neurotouch scores showed lower postoperative VAS scores at different time periods. Preoperative VAS scores, algometer average scores, neurotouch scores, and HADS scores were considered as independent variables (predictors) for postoperative VAS at 6 hours period. By the multivariate analysis, factors like preoperative VAS scores, algometer average scores, and HADS scores were statistically significant (p<.05). There was a significant correlation between algometer average scores (p<.001) with the breakthrough analgesics.

CONCLUSION

Preoperative assessment of pain sensitivity can predict postoperative analgesic requirements and aid in recovery. Patients with a lower pain threshold should be counseled preoperatively and also receive a better titration of analgesics perioperatively.

Predicting postoperative pain by using preoperative pain threshold in response to electrical stimulus in women undergoing gynaecological cancer surgery - Single-arm, prospective, observational study

Background and Aims

Individual variability leading to different pain experiences makes pain prediction challenging. This study aimed to evaluate whether preoperative electrical pain threshold testing is predictive of postoperative pain.

Methods

Following ethics committee approval and registration of the trial, 40 consenting patients undergoing open laparotomy (interval debulking surgery) for ovarian cancer were included in the study. Electrical stimulus (maximum of 256 μA) was used preoperatively to determine the current perception threshold (CPT) and pain equivalent current (PEC). A numerical rating scale (NRS; 0-10, with 0 indicating no pain and 10 indicating severe pain) was used to assess pain. All patients received intravenous paracetamol in accordance to body weight, diclofenac (1 mg/kg, maximum 50 mg), and tramadol (1 mg/kg, maximum 50 mg) eight hourly for 24 hours. The preoperative PEC was compared with worst pain score (PS) at movement at the end of 24 hours. PEC was also compared with average PS at rest, at movement, and with opioid requirement (24 hours).

Results

The median values of CPT and PEC were 12.51 (45 [10.1-14.6]) μA and 94.75 (174 [48.8-94.7]) μA, respectively. A moderate correlation was observed between PEC and worst PS (P = 0.01, r = -0.402), with patients having PEC less than 60 μA being associated with moderate-to-severe PS. There was no correlation between PEC and average PS at rest (P = 0.16, r = 0.225), at movement (P = 0.46, r = 0.119), and the postoperative opioid consumption in the first 24 hours (P = 0.50, r = -0.110).

Conclusion

There is a moderate association between preoperative pain threshold in response to electrical stimulus and worst PS in the postoperative period following interval debulking surgery for ovarian cancer.

Effect of music listening on perioperative anxiety, acute pain and pain catastrophizing in women undergoing elective cesarean delivery: a randomized controlled trial

BACKGROUND

Anxiety may adversely impact mother and her newborn. Music listening is a safe and efficacious treatment that may to reduce perioperative anxiety. The effect on acute pain and pain catastrophizing scores remains unclear. We aimed to determine whether perioperative music listening reduces anxiety, acute pain, and pain catastrophizing scale (PCS) scores following elective cesarean delivery under spinal anesthesia.

METHODS

After randomization into music listening and control groups, baseline patient characteristics, visual analog scale-anxiety (VAS-A) scores, pain scores, PCS total and sub-scores, and music preferences were collected preoperatively. Before surgery, parturients in the experimental group listened to music of their own choice for 30 min. Music listening was continued during administration of spinal anesthesia and cesarean delivery, and for 30 min following surgery. Postoperative VAS-A score, acute pain score, PCS scores, music preferences, satisfaction score, and feedback were recorded.

RESULTS

We analyzed 108 parturients (music: n = 53; control: n = 55). Music listening was associated with reduced postoperative VAS-A (mean difference (MD) -1.43, 95%CI -0.63 to -2.22), PCS total score (MD -6.39, 95%CI -2.11 to -10.66), PCS sub-scores on rumination (MD -1.68, 95%CI -0.12 to -3.25), magnification (MD -1.53, 95%CI -0.45 to -2.62), and helplessness (MD -3.17, 95%CI -1.29 to -5.06) sub-scores. There was no significant difference in postoperative acute pain scores. The majority (> 95%) of parturients reported "excellent" and "good" satisfaction with music listening, and most provided positive feedback.

CONCLUSION

Perioperative music listening was associated with reduced postoperative anxiety and lower pain catastrophizing. Based on the good patient satisfaction and positive feedback received, the use of music listening in the obstetric setting is recommended.

TRIAL REGISTRATION

This study was registered on Clinicaltrials.gov NCT03415620 on 30/01/2018.

Outcomes of a QST Protocol in Healthy Subjects and Chronic Pain Patients: A Controlled Clinical Trial

Chronic pain is an important cause of disability with a high burden to society. Quantitative sensory testing (QST) is a noninvasive multimodal method used to discriminate the function of nerve fibers. The aim of this study is to propose a new, reproducible, and less time-consuming thermal QST protocol to help characterize and monitor pain. Additionally, this study also compared QST outcomes between healthy and chronic pain subjects. Forty healthy young/adult medical students and fifty adult/elderly chronic pain patients were evaluated in individual sessions including pain history, followed by QST assessments divided into three proposed tests: pain threshold, suprathreshold, and tonic pain. In the chronic pain group, a significantly higher pain threshold (hypoesthesia) and a higher pain sensibility (hyperalgesia) were demonstrated at threshold temperature when compared to healthy participants. The sensitivity to the suprathreshold and tonic stimulus did not prove to be significantly different between both groups. The main results demonstrated that the heat threshold QST tests can be helpful in evaluating hypoesthesia and that the sensitivity threshold temperature test can demonstrate hyperalgesia in individuals with chronic pain. In conclusion, this study demonstrates the importance of using tools such as QST as a complement to detect changes in several pain dimensions.

Associations between postpartum pain, mood, and maternal-infant attachment and parenting outcomes

Pain and depression are interrelated, and worse postpartum pain has been associated with postpartum depression. It remains unclear whether improved pain and mood after delivery can also improve maternal parenting. Few studies have examined relationships between postpartum pain and negative mood (anxiety or depression) or their effects on parent-infant relationship outcomes. The purpose of this study was to explore the relationships between postpartum pain, mood, parent-infant attachment, parenting self-efficacy, and infant development. This was a prospective longitudinal observational pilot study of nulliparous women enrolled at the third trimester and presenting for labor and delivery at term gestation. Baseline third trimester assessments included validated inventories of pain (the brief pain inventory, BPI), depression (the Edinburgh postnatal depression screen, EPDS), anxiety (the state trait anxiety inventory, STAI), multidimensional scale of perceived social support (perceived social support scale, MSPSS) and perceived stress scale (PSS). Demographic and labor characteristics were recorded. At 6 weeks and 3 months postpartum, self-reported assessments included EPDS, STAI, BPI, maternal parent infant attachment scale (MPAS), and perceived maternal parenting self-efficacy (PMP-SE). Child development outcomes were assessed at 6 weeks and 3 months using the Ages and Stages Questionnaire (ASQ). Univariable linear regression assessed the relationships between pain and parenting outcomes (MPAS and PMP-SE), including potential interactions between pain and mood for parenting outcomes. Generalized linear modeling was used to explore the relationships between postpartum pain, parenting outcomes, and child development outcomes. Of 187 subjects, 87 had complete data on parent-infant attachment and parenting self-efficacy data at 3 months. Lower "pain right now" scores (BPI) on postpartum day 1 was associated with higher maternal-infant attachment (MPAS) at 6 weeks postpartum (Estimate - 1.8, 95% CI - 3.4 to - 0.2, P < 0.03) but not at 3 months (Estimate 0.23 95% CI - 1.1 to 1.6, P = 0.7). Higher depression (EPDS) scores at 6 weeks were also associated with lower MPAS scores at 6 weeks (Estimate - 1.24, 95% CI - 2.07 to - 0.40, P = 0.004). However, there was no evidence that the relationship between pain and MPAS varied by depression score at 6 weeks (P = 0.42). Pain scores at baseline, six weeks, or three months did not correlate with parenting outcomes (MPAS, PMP-SE) at six weeks or three months. Results of the generalized linear modeling revealed relationships between pain, age, anxiety (STAI), and depression (EPDS) predictors, and the outcomes of parenting (MPAS, PMP-SE) and gross motor and personal-social (ASQ) aspects of infant development. There is a pattern of association between worse postpartum pain, anxiety, and depression with worse parenting outcomes. Depression and pain may also affect infant development, but future work is required to replicate and characterize these potential relationships.

Predictive Validity and Patterns of Change Over Time of the Sensitivity to Pain Traumatization Scale: A Trajectory Analysis of Patients Seen by the Transitional Pain Service Up to Two Years After Surgery

Purpose

The Sensitivity to Pain Traumatization Scale (SPTS-12) was developed to assess the propensity to develop a traumatic stress response to pain. The SPTS-12 is a reliable and valid scale with a one-factor structure. The aim of the present study is to further examine the psychometric properties of the SPTS-12 by evaluating its criterion validity and how scores change over time in a sample of postsurgical patients at the Toronto General Hospital Transitional Pain Service.

Participants and Methods

361 adults (55% male; M_age = 50.6 years, SD_age = 14.3) completed questionnaires assessing symptoms of pain, anxiety, depression, and trauma at multiple visits to the Transitional Pain Service after surgery. Latent-class growth mixture modeling defined prototypical longitudinal patterns (latent trajectories) of SPTS-12 scores up to two years after surgery. One-way ANOVAs examined how trajectory classes differed over time on measures of daily opioid use (mg morphine equivalents (MME)), average pain intensity, pain interference, and depressive symptoms.

Results

The final model consisted of five SPTS-12 trajectory groups; two characterized by a flat and unchanging pattern and three showing a small but statistically significant decrease over time. Analysis of pain-related outcomes predicted by SPTS-12 trajectories provided evidence of criterion validity of the SPTS-12. SPTS-12 trajectories did not significantly differ on daily MME at any time. Average pain, pain interference, and depression scores significantly differed across SPTS-12 trajectory groups at two or more postsurgical visits (all p < 0.05).

Conclusion

The SPTS-12 shows fairly stable patterns and predicts important pain-related and psychosocial outcomes over time. Two SPTS-12 trajectories (#2 and #5) with high scores, comprising ~28% of the total sample, are associated with problematic outcomes on several pain and psychosocial measures. Targeting patients with high SPTS-12 scores for presurgical psychological treatment may prove beneficial in reducing the impact of CPSP.

Pain Intensity Predicts Pain Catastrophizing During the Postpartum Period: A Longitudinal Random Intercept Cross-Lagged Panel Study

OBJECTIVE

Pain catastrophizing is an important psychological predictor of pain. Recent evidence suggests the relationship between catastrophizing and pain intensity could be bidirectional, but most studies have been conducted on chronic pain patients and using criticized statistical methods. The present study aimed to examine if the relationship between pain intensity and catastrophizing was bidirectional in the context of childbirth.

METHODS

A total of 504 women without chronic pain were recruited on their 32-37 gestational week. They completed measures of catastrophizing and pain intensity on the first encounter and then again at 1, 3, and 6 months postpartum. The temporal relationship between the variables was assessed using a random intercept cross-lagged panel model.

RESULTS

The hypothesis of reciprocal association did not receive support, as pain intensity predicted catastrophizing during the postpartum period, but catastrophizing did not show an effect over pain intensity at any moment.

CONCLUSIONS

Pain intensity predicting catastrophizing is consistent with previous literature, while the lack of effect of catastrophizing over pain intensity is an unexpected result, which may suggest that catastrophizing plays a different role in the postpartum period. These results highlight the importance of timely efforts for pain management during the postpartum period and contribute to the theoretical conceptualization of catastrophizing.

The Current Consideration, Approach, and Management in Postcesarean Delivery Pain Control: A Narrative Review

Optimal postoperative analgesia has a significant impact on patient recovery and outcomes after cesarean delivery. Multimodal analgesia is the core principle for cesarean delivery and pain management. For a standard analgesic regimen, the use of long-acting neuraxial opioids (e.g., morphine) and adjunct drugs, such as scheduled acetaminophen and nonsteroidal anti-inflammatory drugs, is recommended unless contraindicated. Oral or intravenous opioids should be reserved for breakthrough pain. In addition to the aforementioned use of multimodal analgesia, preoperative evaluation is critical to individualize the analgesic regimen according to the patient requirements. Risk factors for severe postoperative pain or analgesia-related adverse effects will require modifications to the standard analgesic regimen (e.g., the use of ketamine, gabapentinoids, or regional anesthetic techniques). Further investigation is required to determine analgesic drugs or dose alterations based on preoperative predictions for patients at risk of severe pain. Outcomes beyond pain and analgesic use, such as functional recovery, should be determined to evaluate analgesic treatment protocols.

Associations between postoperative analgesic consumption and distress tolerance, anxiety, depression, and pain catastrophizing: a prospective observational study

BACKGROUND

Patients' postoperative treatment might be affected by their psychological state. The study aimed to evaluate the effects of anxiety, coping ability (stress tolerance), depression, and pain catastrophizing on analgesic consumption in patients scheduled for sleeve gastrectomy.

METHODS

This prospective observational study consisted of 72 patients. The Distress Tolerance Scale (DTS), Beck Anxiety Inventory (BAI), Beck Depression Inventory (BDI), and Pain Catastrophizing Scale (PCS) were completed in the preoperative period. In the postoperative period, pain intensity, as measured with the Visual Analogue Scale (VAS), and morphine consumption (mg) were evaluated after 2, 6, 8, and 24 hours. Total morphine consumption was recorded.

RESULTS

The results revealed a strong negative correlation between distress tolerance and postoperative total morphine consumption (r = -0.702, p < 0.001). There was a strong positive correlation between total morphine consumption and pain catastrophizing (r = 0.801, p < 0.001). A moderate positive correlation was observed between total morphine consumption and anxiety and between total morphine consumption and depression (r = 0.511, p < 0.001; r = 0.556, p < 0.001, respectively). Linear regression revealed that distress tolerance, anxiety, depression, and pain catastrophizing are predictors of postoperative morphine consumption (β = 0.597, p < 0.001; β = 0.207, p = 0.036; β = 0.140, p = 0.208; β = 0.624, p < 0.001, respectively).

CONCLUSIONS

Distress tolerance, anxiety, depression, and pain catastrophizing can be predictive of postoperative analgesic consumption. In the estimation of postoperative analgesic consumption, distress tolerance, as well as anxiety, depression, and pain catastrophizing, were found to be important predictors.

Opioid prescription-use after cesarean delivery: an observational cohort study

OBJECTIVE

To evaluate current opioid prescription practices following a cesarean delivery.

METHODS

Women were asked to participate in a prospective observational cohort study following a cesarean delivery. Participants were asked about their opioid use after discharge, amount leftover, subjective pain score, and satisfaction.

RESULTS

A total of 344 women had cesarean deliveries during the study period, 242 were approached, 171 met eligibility criteria, and 109 were included in the analysis. Women in our study were predominantly African American (66.1%), high school graduates (32.1%), publicly insured (65.1%), single (55%) working mothers (68.8%). Most had been previously prescribed opioids (70.6%), of which 58.4% had a prior cesarean delivery. Only 78.8% of study participants took their opioid prescriptions, and 89.6% had an average of 17 pills leftover. The number of pills taken correlated with those prescribed in the study. Improved satisfaction in pain control with opioid and non-opioid alternatives was associated with a decrease in opioids used. Similarly, the participants' perception of their abundant prescription quantity was associated with a decrease in prescription taken.

CONCLUSION

Women were prescribed excess opioids. Excess opioids accounted for 63.3% of all pills filled, a total of 1670 pills leftover, most of which were stored in an unlocked location (75.6%). Our data showed a discrepancy of pills prescribed (24) compared to those used (10), which was also perceived as enough or too many by our participants. Our study demonstrates that women would benefit from fewer opioid pills and a discussion based on their pain perception.

Preoperative Pressure Pain Threshold Is Associated With Postoperative Pain in Short-Stay Anorectal Surgery: A Prospective Observational Study

BACKGROUND:

Postoperative pain management is key for patient satisfaction. Pressure pain threshold (PPT) has been studied in some surgical cohorts but has not been studied in relationship to acute postoperative pain in short-stay patients undergoing anorectal surgery. We hypothesized that preoperative finger PPT measurements can identify respective patients with higher postoperative pain. Aiming to understand the relationship with subjective postoperative pain perception, we tested the hypotheses that preoperative PPT is associated with postoperative Visual Analog Scale (VAS) pain scores and correlates with postoperative analgesic consumption in short-stay patients undergoing anorectal surgery.

METHODS:

We prospectively assessed preoperative PPT in a cohort undergoing anorectal surgery, known as a moderately to severely painful procedure. Linear mixed-effects models were used to assess the relationship with postoperative VAS pain scores at 1 and 3 days as well as 4 weeks postoperatively. Logistic regression was used to study the relationship with additional postoperative analgesic consumption.

RESULTS:

We studied 128 patients and found that preoperative PPT is significantly associated with postoperative pain (P value for interaction = .025). Logistic regression modeling additionally revealed an association between the preoperative PPT and the need for additional postoperative analgesics, with odds of requiring additional analgesia decreasing by about 10% for each 1-point increase in PPT (odds ratio [OR] = 0.90; 95% confidence interval [CI], 00.81–0.98; P = .012).

CONCLUSIONS:

Preoperative finger PPT is associated with postoperative pain and might help identify patients who are at risk of developing more severe postoperative pain on anorectal surgery. Especially in ambulatory and short-stay settings, this approach can help to address patients’ high variability in pain sensitivity to facilitate appropriate postoperative analgesia, timely discharge, and prevent readmission.

Quantitative Sensory Testing to Predict Postoperative Pain

Purpose of Review

We review the relevance of quantitative sensory testing (QST) in light of acute and chronic postoperative pain and associated challenges.

Recent Findings

Predicting the occurrence of acute and chronic postoperative pain with QST can help identify patients at risk and allows proactive preventive management. Generally, central QST testing, such as temporal summation of pain (TSP) and conditioned pain modulation (CPM), appear to be the most promising modalities for reliable prediction of postoperative pain by QST. Overall, QST testing has the best predictive value in patients undergoing orthopedic procedures.

Summary

Current evidence underlines the potential of preoperative QST to predict postoperative pain in patients undergoing elective surgery. Implementing QST in routine preoperative screening can help advancing traditional pain therapy toward personalized perioperative pain medicine.

Preoperative quantitative sensory testing and robot-assisted laparoscopic hysterectomy for endometrial cancer: can chronic postoperative pain be predicted?

Objectives Chronic postoperative pain is prevalent after robot-assisted laparoscopic hysterectomy for endometrial cancer. Preoperative Quantitative Sensory Testing (QST) has been utilized to identify patients at risk of developing chronic postoperative pain after a range of surgical procedures. The aim of this prospective, observational study was to (1) determine the prevalence of chronic postoperative pain, (2) assess selected preoperative risk factors for chronic postoperative pain, and (3) evaluate if preoperative QST profiling could predict the development of chronic postoperative pain following robot-assisted laparoscopic hysterectomy for endometrial cancer. Methods One-hundred and sixty consecutive patients were included and handheld pressure algometry, cuff pressure algometry, temporal summation of pain, conditioned pain modulation, and heat pain thresholds were assessed prior to surgery. Patients were asked to fill out a questionnaire concerning pain in the pre- and post-operative time period six months after surgery. Chronic postoperative pain was defined as persistent, moderate to severe pain (mean visual analogue scale (VAS)≥3) on a daily basis six months after surgery. Results The prevalence of chronic postoperative pain after robot-assisted laparoscopic hysterectomy for endometrial cancer was of 13.6% (95% CI 8.4-20.4%). Patients that would develop chronic postoperative pain had a lower BMI (p=0.032), a higher prevalence of preoperative pelvic pain (p<0.001), preoperative heat pain hyperalgesia (p=0.043) and a higher level of acute postoperative pain (p<0.001) when compared to patients that would not develop chronic postoperative pain. A logistic regression model demonstrated that the presence of preoperative pelvic pain was a significant, independent predictive risk factor for development of chronic postoperative pain (OR=6.62, 95% CI 2.26-19.44), whereas none of the QST parameters could predict postoperative pain. Conclusions Preoperative QST assessment could not predict the development of chronic postoperative pain despite preoperative heat pain hyperalgesia in patients that would develop chronic postoperative pain.

Risk Factors Associated with Development of Acute and Sub-Acute Post-Cesarean Pain: A Prospective Cohort Study

BACKGROUND

Although cesarean delivery is one of the most commonly performed surgical procedures, robust data regarding post-cesarean pain is still lacking. Recent studies showed an association between pain upon local anesthetic (LA) injection for spinal anesthesia, or the use of a "three simple questions", and acute post-cesarean pain. Nevertheless, these assessments have yet to be validated further, despite their relative ease of use. We aimed to assess the association between pain score upon LA injection with acute post-cesarean pain after 24 hours at rest (primary outcome) and sub-acute post-cesarean pain lasting for 4 weeks or more (secondary outcome).

METHODS

Women undergoing cesarean delivery under spinal anesthesia were given pre-operative questionnaires on pain and psychological vulnerability. We also assessed the pain score upon LA injection and mechanical temporal summation. Univariate and multivariable logistic regressions were performed.

RESULTS

The incidence of moderate-to-severe acute post-cesarean pain at 24 hours was 21.0% (95% CI=16.6-27.6%) (48 of 217 patients). Pain score upon LA injection was not significantly associated with acute post-cesarean pain after 24 hours at rest (unadjusted OR=1.10, 95% CI=0.95-1.27, P=0.21). However, pain score upon LA injection was significantly associated with sub-acute post-cesarean pain (adjusted OR=1.29, 95% CI=1.07-1.55, P=0.0089) with significant covariate of increased pre-operative central sensitization inventory (CSI) scores (adjusted OR=1.05, 95% CI=1.01-1.09, P=0.0111; area under the curve (AUC)=0.691).

CONCLUSION

There was no association between increased pain score upon LA injection and acute post-cesarean pain, but it was associated with sub-acute post-cesarean pain. Further work is needed to define pain score upon LA injection as a convenient pragmatic measure of risk stratifying patients predisposed to sub-acute post-cesarean pain.

Magnetic Resonance Imaging in Pediatric Migraine

This literature review provides an overview of the research using magnetic resonance imaging (MRI) in pediatric migraine and compares findings with the adult migraine literature. A literature search using PubMed was conducted using all relevant sources up to February 2019. Using MRI methods to categorize and explain pediatric migraine in comparison with adult migraine is important, in order to recognize and appreciate the differences between the two entities, both clinically and physiologically. We aim to demonstrate the differences and similarities between pediatric and adult migraine using data from white matter and gray matter structural studies, cerebral perfusion, metabolites, and functional MRI (fMRI) studies, including task-based and resting-state blood oxygen level-dependent studies. By doing this we identify areas that need further research, as well as possible areas where intervention could alter outcomes.

Obstetric pain correlates with postpartum depression symptoms: a pilot prospective observational study

BACKGROUND

Data linking labor pain and postpartum depression are emerging. Robust, prospective evaluations of this relationship while factoring other important variables are lacking. We assessed perinatal pain and other factors predicting postpartum depression (PPD) symptoms.

METHODS

Third trimester women, stratified by a priori plan to receive or avoid labor epidural analgesia, were longitudinally followed from the prenatal period through labor and delivery, until 6 weeks and 3 months postpartum. Electronic pain data was collected hourly during labor in real time, capturing pain unpleasantness, intensity, pain management satisfaction, and expectations. Prenatal and postpartum data included anxiety, depression, the Brief Pain Inventory (BPI), pain catastrophizing, resiliency, and perceived social support and stress. The primary outcome was Edinburgh Postnatal Depression Score (EPDS) as a marker of PPD symptoms. The primary pain variable of interest was labor pain emotional valence (unpleasantness burden, area under the curve for entire labor duration). Single and multivariable linear regressions examined perinatal pain variables in relation to EPDS.

RESULTS

Of 72 subjects included, 55 planned/received labor epidural analgesia and 17 planned avoidance/avoided it. In the planned epidural group, the emotional valence of labor pain independently predicted six-week EPDS (labor pain unpleasantness burden, R² = 0.42, P = 0.002). In addition to labor pain, prenatal and postpartum pain variables from the BPI independently predicted six-week EPDS. Three-month depression scores were linked to labor and acute pain (6 weeks postpartum), but not to chronic (3 months postpartum) pain variables. Intrapartum pain management satisfaction and expectations were largely met or exceeded and did not differ between analgesia groups.

CONCLUSION

For susceptible women, pain at all perinatal time points-prenatal, labor, and postpartum-appear to be independently linked to depression scores at 6 weeks postpartum. The relationships are true, even though satisfaction and expectations regarding labor pain management were met or exceeded. These data support the concept that labor and acute postpartum pain influences both acute and long-term PPD symptoms, although additional data are needed to assess how analgesia preference interacts with these relationships.

Application of preoperative assessment of pain induced by venous cannulation in predicting postoperative pain in patients under laparoscopic nephrectomy: a prospective observational study

BACKGROUND

Postoperative pain is the most prominent concern among surgical patients. It has previously been reported that venous cannulation-induced pain (VCP) can be used to predict postoperative pain after laparoscopic cholecystectomy within 90 mins in the recovery room. Its potential in predicting postoperative pain in patients with patient-controlled intravenous analgesia (PCIA) is worth establishing. The purpose of this prospective observational study was to investigate the application of VCP in predicting postoperative pain in patients with PCIA during the first 24 h after laparoscopic nephrectomy.

METHODS

One hundred twenty patients scheduled for laparoscopic nephrectomy were included in this study. A superficial vein on the back of the hand was cannulated with a standard-size peripheral venous catheter (1.1 × 3.2 mm) by a nurse in the preoperative areas. Then the nurse recorded the VAS score associated with this procedure estimated by patients, and dichotomized the patients into low response group (VAS scores < 2.0) or high response group (VAS scores ≥2.0). After general anesthesia and surgery, all the patients received the patient-controlled intravenous analgesia (PCIA) with sufentanil. The VAS scores at rest and on coughing at 2 h, 4 h, 8 h, 12 h, 24 h, the effective number of presses and the number of needed rescue analgesia within 24 h after surgery were recorded.

RESULTS

Peripheral venous cannulation-induced pain score was significantly correlated with postoperative pain intensity at rest (rs = 0.64) and during coughing (rs = 0.65), effective times of pressing (rs = 0.59), additional consumption of sufentanil (rs = 0.58). Patients with venous cannulation-induced pain intensity ≥2.0 VAS units reported higher levels of postoperative pain intensity at rest (P < 0.0005) and during coughing (P < 0.0005), needed more effective times of pressing (P < 0.0005) and additional consumption of sufentanil (P < 0.0005), and also needed more rescue analgesia (P = 0.01) during the first 24 h. The odds of risk for moderate or severe postoperative pain (OR 3.5, 95% CI 1.3-9.3) was significantly higher in patients with venous cannulation-induced pain intensity ≥2.0 VAS units compared to those <2.0 VAS units.

CONCLUSIONS

Preoperative assessment of pain induced by venous cannulation can be used to predict postoperative pain intensity in patients with PCIA during the first 24 h after laparoscopic nephrectomy.

TRIAL REGISTRATION

We registered this study in a Chinese Clinical Trial Registry (ChiCTR) center on July 6 2019 and received the registration number: ChiCTR1900024352.

Validation of a visual analogue scale for the evaluation of the postoperative anxiety: A prospective observational study

AIM

Anxiety affects the perception of pain during the postoperative period. A simple evaluation scale could improve the management of this component. The objective of this study was to evaluate the reproducibility and the consistency of a visual analogue scale for anxiety compared with the reference method, the State-Trait Anxiety Inventory (STAI).

DESIGN

Observational, prospective, monocentric study of 500 patients in the post-anaesthetist care unit. Anxiety was evaluated using both the visual analogue scale for anxiety and the STAI in perioperative patients. Consistency between the visual analogue scale for anxiety and the STAI, detection thresholds and factors predicting anxiety were researched.

RESULTS

A correlation was found between the visual analogue scale for anxiety and the STAI. There was also a correlation between pain and anxiety. Analysis of receiver operating characteristic (ROC) curves showed a visual analogue scale for anxiety threshold of 34/100 allowing the identification of patients with or without anxiety. Predictive factors for anxiety are female gender, use of benzodiazepine in premedication, emergency surgery and significant pain in the post-anaesthetist care unit. In summary, visual analogue scale for anxiety is a useful tool for detecting the anxiety component of postoperative pain. It could be used in association with covariates of interest to improve anxiety management during the postoperative period.

Predicting Severity of Acute Pain After Cesarean Delivery: A Narrative Review

Cesarean delivery is one of the most common surgical procedures in the United States, with over 1.3 million performed annually. One-fifth of women who undergo cesarean delivery will experience severe pain in the acute postoperative period, increasing their risk of developing chronic pain and postpartum depression, and negatively impacting breastfeeding and newborn care. A growing body of research has investigated tools to predict which patients will experience more severe pain and have increased analgesic consumption after cesarean delivery. These include quantitative sensory testing, assessment of wound hyperalgesia, response to local anesthetic infiltration, and preoperative psychometric evaluations such as validated psychological questionnaires and simple screening tools. For this review, we searched MEDLINE, the Cochrane database, and Google Scholar to identify articles that evaluated the utility of various tools to predict severe pain and/or opioid consumption in the first 48 hours after cesarean delivery. Thirteen articles were included in the final review: 5 utilizing quantitative sensory testing, including patient responses to pressure, electrical, and thermal stimuli; 1 utilizing hyperalgesia testing; 1 using response to local anesthetic wound infiltration; 4 utilizing preoperative psychometric evaluations including the State-Trait Anxiety Inventory, the Pain Catastrophizing Scale, the Pittsburgh Sleep Quality Index, the Hospital Anxiety and Depression Scale, and simple questionnaires; and 2 utilizing a combination of quantitative sensory tests and psychometric evaluations. A number of modalities demonstrated statistically significant correlations with pain outcomes after cesarean delivery, but most correlations were weak to modest, and many modalities might not be clinically feasible. Response to local anesthetic infiltration and a tool using 3 simple questions enquiring about anxiety and anticipated pain and analgesic needs show potential for clinical use, but further studies are needed to evaluate the utility of these predictive tests in clinical practice.

Persistent pain after cesarean delivery

The incidence of persistent pain after cesarean deliveries (CD) varies but is much lower than after comparable surgeries. However, with over four million deliveries annually and a rising CD rate, even a low prevalence of persistent pain after CD impacts many otherwise healthy young women. Consideration of the pathophysiology of persistent pain after surgery and the risk factors predisposing women to persistent and chronic pain after CD provides insights into the prevention and treatment of persistent pain; and improves the quality of care and recovery after CD. The findings that the peripartum state and oxytocin confer protection against persistent pain may provide new and interesting perspectives for the prevention and treatment of chronic pain caused by trauma or surgery. Predictive tools available to identify and target patients at high risk of acute and chronic pain have mostly weak to modest predictive correlations and many are either not clinically feasible or too time-consuming to apply. Persistent pain has been linked to the severity of acute postoperative pain and opioid exposure. Modified surgical techniques, neuraxial anesthesia and opioid-sparing analgesia may help limit the development of persistent and chronic pain. The goal of this narrative review is to examine the incidence of persistent pain after CD; review briefly the underlying pathophysiology of persistent pain and the transition from acute to chronic pain (with particular emphasis on the uniqueness after CD); and to review modifiable risk factors and prevention strategies that identify at-risk patients and allow tailored treatment.

Intolerance of Uncertainty and Anxiety-Related Dispositions Predict Pain During Upper Endoscopy

Although sedatives can defuse anxiety and relieve pain, Esophagogastroduodenoscopy (EGD) still is uncomfortable and threatening for some patients. Identifying patients who tolerate digestive endoscopy less well remains difficult. Using a prospective design and a multimodal assessment of pain, the present study evaluated how anxiety-related variables predicted subsequent pain outcomes. Sixty-two consecutive patients referred for elective EGD were assessed for intolerance of uncertainty (IU), procedure-related worries, anxiety sensitivity and health distress before endoscopy. During endoscopy, a doctor rated patients’ pain behavior. After complete recovery from sedation, the patients retrospectively rated endoscopy pain and situation specific catastrophizing thoughts. Descriptive analyses showed that patients undergoing EGD for the first time were more distressed and anxious than patients accustomed to the procedure and needed a higher sedative dose. Notwithstanding sedation, the behavioral rating of pain was above the cut-off value for probable pain for more than half of the patients. IU assessed before endoscopy predicted situational pain catastrophizing (PC) and self-reported pain after endoscopy through procedure related worries. Situational PC not only mediated the effect of worry, but also female gender and younger age were associated with self-reported pain through increased catastrophizing thoughts. Health distress and anxiety sensitivity predicted PC only for women, younger patients, and those not accustomed to the procedure. Our study showed that psychological preparation before sedation is needed especially for first-timers, women, and younger patients, addressing maladaptive cognitive beliefs and acquainting patients with the somatic sensations that they might experience during the procedure.

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.

Pain Catastrophizing and Anxiety are Associated With Heat Pain Perception in a Community Sample of Adults With Chronic Pain

BACKGROUND

The principle aim of this study was to investigate the associations between heat pain (HP) perception, pain catastrophizing, and pain-related anxiety in a heterogenous cohort of community-dwelling adults with chronic pain admitted to a 3-week outpatient pain rehabilitation program.

METHODS

All adults consecutively admitted to an outpatient pain rehabilitation program from July 2009 through January 2011 were eligible for study recruitment (n=574). Upon admission, patients completed the Pain Catastrophizing Scale (PCS), the short version of the Pain Anxiety Symptoms Scale (PASS-20), and HP perception was assessed using a standardized quantitative sensory testing (QST) method of levels.

RESULTS

Greater PCS scores were significantly correlated with lower standardized values of HP threshold (HP 0.5) (P=0.006) and tolerance (HP 5) (P=0.003). In a multiple variable model adjusted for demographic and clinical factors known to influence HP perception, every 10-point increase in the PCS was associated with a -0.124 point change in HP 0.5 (P=0.014) and a -0.142 change in HP 5 (P=0.014) indicating that participants with higher PCS scores had lower HP thresholds and tolerances, respectively. Similarly, greater PASS-20 scores significantly correlated with lower standardized values of HP 0.5 and HP 5. In a multiple variable model, every 10-point increase in the PASS-20 was associated with a -0.084 point change in HP 0.5 (P=0.005) and a -0.116 point change in HP 5 (P=0.001) indicating that participants with higher PASS-20 scores had lower HP thresholds and tolerances, respectively.

CONCLUSIONS

The findings of this study extend the use of a standardized method for assessing HP in a heterogenous sample of adults with chronic pain. Although pain catastrophizing shares significant variance with pain-related anxiety, our findings suggest that either measure would be appropriate for use in future studies that incorporate the QST method of levels.

Predictors of Acute Postsurgical Pain After Inguinal Hernioplasty

Acute postsurgical pain (APSP) is a common and anticipated problem after surgery with detrimental consequences if not appropriately managed. This study examined the independent and joint contribution of presurgical demographic, clinical, and psychological variables as predictors of APSP intensity, evaluated using an 11-point numeric rating scale, after inguinal hernioplasty, one of the most performed surgeries worldwide. In a prospective observational cohort study, a consecutive sample of 135 men undergoing hernioplasty was assessed before and 48 hours after surgery. When adjusted for depression, helplessness, and magnification scores, a multiple hierarchical regression analysis revealed that younger age (β = -.247, P < .005), previous chronic pain (β = .175, P < .05), presurgical anxiety (β = .235, P < .05), and the rumination component of pain catastrophizing (β = .222, P < .05) were significant predictors of APSP intensity. The integrative predictive model found in this study revealed the simultaneous influence that demographic, clinical, and psychological factors have on APSP after inguinal hernioplasty. Therefore, these results improve knowledge on APSP predictors after inguinal hernioplasty and highlight potential modifiable intervention targets, such as anxiety and pain catastrophizing (rumination), for the design of interventions focused on APSP prevention and management. Hence, taken together, these findings lend support for the inclusion of presurgical screening and psychological interventions among surgical patients at risk for higher APSP intensity.

PERSPECTIVE

This study found that, when adjusted for depression, helplessness, and magnification scores, the variables younger age, previous chronic pain, presurgical anxiety, and the rumination component of pain catastrophizing are significant predictors of APSP intensity after inguinal hernioplasty. These findings improve knowledge on APSP and highlight potential modifiable intervention targets for the design of interventions focused on APSP prevention and management.

Are preoperative experimental pain assessments correlated with clinical pain outcomes after surgery? A systematic review

BACKGROUND

Pain after surgery is not uncommon with 30% of patients reporting moderate to severe postoperative pain. Early identification of patients prone to postoperative pain may be a step forward towards individualized pain medicine providing a basis for improved clinical management through treatment strategies targeting relevant pain mechanisms in each patient. Assessment of pain processing by quantitative sensory testing (QST) prior to surgery has been proposed as a method to identify patients at risk for postoperative pain, although results have been conflicting. Since the last systematic review, several studies investigating the association between postoperative pain and more dynamic measures of pain processing like temporal summation of pain and conditioned pain modulation have been conducted.

OBJECTIVES

According to the PRISMA guidelines, the aim of this systematic review was to evaluate whether assessment of experimental pain processing including measures of central pain mechanisms prior to surgery was associated with pain intensity after surgery.

METHODS

Systematic database searches in PubMed and EMBASE with the following search components: QST, association, and postoperative pain, for studies that assessed the association between QST and pain after surgery were performed. Two authors independently reviewed all titles and abstracts to assess their relevance for inclusion. Studies were included if (1) QST was performed prior to surgery, (2) pain was assessed after surgery, and (3) the association between QST and pain after surgery was investigated. Forty-four unique studies were identified, with 30 studies on 2738 subjects meeting inclusion criteria. The methodological quality of the include studies was assessed and data extraction included study population, type of surgery, QST variables, clinical pain outcome measure and main result.

RESULTS

Most studies showed moderate to high risk of bias. Type of surgery investigated include 7 studies on total knee replacement, 5 studies on caesarean section, 4 studies on thoracic surgery, 2 studies on herniotomy, 2 studies on hysterectomy/myomectomy, 1 study on tubal ligation, 1 study on gynecologic laparoscopy, 1 study on arthroscopic knee surgery, 1 study on shoulder surgery, 1 study on disc herniation surgery, 1 study on cholecystectomy, 1 study on percutaneous nephrolithotomy, 1 study on molar surgery, 1 study on abdominal surgery, and 1 study on total knee replacement and total hip replacement. The majority of the preoperative QST variables showed no consistent association with pain intensity after surgery. Thermal heat pain above the pain threshold and temporal summation of pressure pain were the QST variables, which showed the most consistent association with acute or chronic pain after surgery.

CONCLUSIONS

QST before surgery does not consistently predict pain after surgery. High quality studies investigating the presence of different QST variables in combination or along with other pain-related psychosocial factors are warranted to confirm the clinical relevance of QST prior to surgery.

IMPLICATIONS

Although preoperative QST does not show consistent results, future studies in this area should include assessment of central pain mechanisms like temporal summation of pressure pain, conditioned pain modulation, and responses to pain above the pain threshold since these variables show promising associations to pain after surgery.

Preoperative sleep quality predicts postoperative pain after planned caesarean delivery

BACKGROUND

Severe post-caesarean pain remains an important issue associated with persistent pain and postpartum depression. Women's sleep quality prior to caesarean delivery and its influence on postoperative pain and analgesic intake have not been evaluated yet.

METHODS

Women undergoing caesarean delivery with spinal anaesthesia (bupivacaine 12 mg, fentanyl 20 μg, morphine 100 μg) were evaluated preoperatively for sleep quality using the Pittsburgh Sleep Quality Index (PSQI) questionnaire (PSQI 0-5 indicating good sleep quality, PSQI 6-21 poor sleep quality). Peak and average postoperative pain scores at rest, movement and uterine cramping were evaluated during 24 h using a verbal numerical pain score (VNPS; 0 indicating no pain and 100 indicating worst pain imaginable), and analgesic intake was recorded. Primary outcome was peak pain upon movement during the first 24 h.

RESULTS

Seventy-eight of 245 women reported good sleep quality (31.2%; average PSQI 3.5 ± 1.2) and 167 poor sleep quality (68.2%; average PSQI 16.0 ± 3.4; p < 0.001). Women with poor sleep quality had significantly higher peak pain scores upon movement (46.7 ± 28.8 vs. 36.2 ± 25.6, respectively; p = 0.006). With multivariable logistic regression analysis, poor sleep quality significantly increased the risk for severe peak pain upon movement (VNPS ≥70; OR 2.64; 95% CI 1.2-6.0; p = 0.02).

DISCUSSION

A significant proportion of women scheduled for caesarean delivery were identified preoperatively as having poor sleep quality, which was associated with more severe pain and increased analgesic intake after delivery. The PSQI score may therefore be a useful tool to predict increased risk for acute post-caesarean pain and higher analgesic requirements, and help tailor anaesthetic management.

SIGNIFICANCE

Multiple studies have evaluated predictors for severe acute pain after caesarean delivery that may be performed in a clinical setting, however, sleep quality prior to delivery has not been included in predictive models for post-caesarean pain. The PSQI questionnaire, a simple test to administer preoperatively, identified that up to 70% of women report poor sleep quality before delivery, and poor sleep quality was associated with increased post-caesarean pain scores and analgesic intake, indicating that PSQI could help identify preoperatively women at risk for severe pain after caesarean delivery.

The Cold Pressor Test as a Predictor of Prolonged Postoperative Pain, a Prospective Cohort Study

INTRODUCTION

Presently, it is difficult to predict which patients are at increased risk of ongoing pain problems postoperatively. This study followed a group of patients from the week before their operation until 3 months after it, to identify potential risk variables.

METHODS

Fifty-four patients undergoing moderate-major gynaecological surgery at Christchurch Women's Hospital were recruited and assessed preoperatively over an 11-week period. At this initial assessment, participants were subjected to a cold pressor test (CPT). Telephonic follow-up was conducted at 6 weeks and 3 months postoperatively, to determine pain status. Information regarding the type of operation and surgical approach was collected from hospital records.

RESULTS

Pain threshold (time taken to report the onset of pain), as measured by the CPT, was significantly predictive of prolonged pain outcomes (area under the curve = 0.80, 95 % CI 0.66, 0.95). Pain tolerance (total time taken to end the CPT voluntarily) was similarly predictive but non-significant (area under the curve = 0.69, 95 % CI 0.47, 0.90).

CONCLUSION

The preoperative cold pressor test shows some promise for predicting ongoing postoperative pain. However, more research is needed to determine the clinical significance of these findings in larger samples and how they could be incorporated into clinical practice.

Chronic persistent post-surgical pain following staging laparotomy for carcinoma of ovary and its relationship to signal transduction genes

Background

The present study was undertaken to evaluate the incidence of chronic persistent post-surgical pain (CPPP) and the role of signal transduction genes in patients undergoing staging laparotomy for carcinoma ovary.

Methods

The present observational study was undertaken following institutional ethical committee approval and informed consent from all the participants. A total 21 patients of ASA grade I to III with age 20−70 years, scheduled for elective staging laparotomy for carcinoma ovary were included. Patients were excluded if had other causes of pain, cognitive dysfunction or chronic neurological disorders. Statistical analysis of pool data was done using SPSS version-17. For various scales like GPE, PDQ, NPSI, the visual analogue scale (VAS), global perceived effect (GPE), the pain DETECT questionnaire (PDQ), and neuropathic pain symptoms inventory (NPSI), one factor repaeted measure ANOVA applied with simple contrast with baseline as on post-operative day 1 (considered as reference and compared with subsequent time-interval), and the P values were adjusted according to "Bonferroni adjustments". In patients with CPPP, the Δct values of mRNA expressions of genes at the end of postoperative day 90 were compared with the baseline control values by one factor repeated ANOVA. P value < 0.005 significant.

Results

The present study demonstrates 38.1% (8 out of 21 patients) incidence of CPPP. The functional status and quality of life as were observed to be significantly diminished in all patients with chronic pain. An up-regulation in the mRNA expression of signal transduction and a positive correlation was noted between the mRNA expression of signal transduction genes and VAS score in all patients with CPPP at the end of postoperative day 90.

Conclusions

The reported incidence of CPPP in patients with carcinoma ovary was 38.1%. An up-regulation and positive correlation between mRNA expression of signal transduction genes and VAS score depicts its potential role in the pathogenesis of CPPP.

A Prospective Cohort Study Evaluating the Ability of Anticipated Pain, Perceived Analgesic Needs, and Psychological Traits to Predict Pain and Analgesic Usage following Cesarean Delivery

Introduction. This study aimed to determine if preoperative psychological tests combined with simple pain prediction ratings could predict pain intensity and analgesic usage following cesarean delivery (CD). Methods. 50 healthy women undergoing scheduled CD with spinal anesthesia comprised the prospective study cohort. Preoperative predictors included 4 validated psychological questionnaires (Anxiety Sensitivity Index (ASI), Fear of Pain (FPQ), Pain Catastrophizing Scale, and Eysenck Personality Questionnaire) and 3 simple ratings: expected postoperative pain (0–10), anticipated analgesic threshold (0–10), and perceived analgesic needs (0–10). Postoperative outcome measures included post-CD pain (combined rest and movement) and opioid used for the 48-hour study period. Results. Bivariate correlations were significant with expected pain and opioid usage (r = 0.349), anticipated analgesic threshold and post-CD pain (r = −0.349), and perceived analgesic needs and post-CD pain (r = 0.313). Multiple linear regression analysis found that expected postoperative pain and anticipated analgesic needs contributed to post-CD pain prediction modeling (R² = 0.443, p < 0.0001); expected postoperative pain, ASI, and FPQ were associated with opioid usage (R² = 0.421, p < 0.0001). Conclusion. Preoperative psychological tests combined with simple pain prediction ratings accounted for 44% and 42% of pain and analgesic use variance, respectively. Preoperatively determined expected postoperative pain and perceived analgesic needs appear to be useful predictors for post-CD pain and analgesic requirements.

Prediction of postoperative pain from assessment of pain induced by venous cannulation and propofol infusion

BACKGROUND

Postoperative pain may lead to delayed mobilization, persisting pain, and psychosocial distress. There are no simple and reliable techniques for prediction of postoperative pain. This study was designed to evaluate if pain induced by venous cannulation or propofol injection can be used to predict postoperative pain.

METHODS

This prospective study included 180 patients scheduled for laparoscopic cholecystectomy. Pain intensity associated with peripheral venous cannulation and administration of propofol preoperatively and pain intensity, and use of opioid postoperatively was recorded.

RESULTS

Patients scoring cannulation-induced pain intensity > 2.0 VAS units were given postoperative opioid more often (65% vs. 36%; P < 0.001), earlier (12 min vs. 90 min; P < 0.001), and in higher doses (4.8 mg vs. 0 mg; P < 0.001), and also reported higher levels of postoperative pain intensity (5.8 vs. 2.9 VAS units; P < 0.001). There were also significant (P < 0.01) correlations with postoperative pain intensity (rs = 0.24), time to opioid administration (rs = -0.26), and total dose of opioid (rs = 0.25). Propofol-induced pain intensity correlated significantly (P < 0.05) with postoperative pain intensity (rs = 0.19).

CONCLUSION

Pain intensity associated with venous cannulation and propofol infusion can easily be evaluated at bedside before surgery without specific equipment or training. Patients scoring > 2.0 VAS units on venous cannulation were found to have 3.4 times higher risk of postoperative pain after laparoscopic cholecystectomy. Low pain intensity associated with venous cannulation and propofol infusion indicate lower risk of postoperative pain.

Prediction of pain in orthodontic patients based on preoperative pain assessment

AIM

To investigate whether pretreatment assessment of experimental pain can predict the level of pain after archwire placement.

METHODS

One hundred and twenty-one general university students seeking orthodontic treatment were enrolled in this study. A cold pressor test was performed to estimate the pain tolerance of subjects before treatment. Self-reported pain intensity was calculated using a 10 cm visual analog scale during the 7 days after treatment. The relationship between pain tolerance and orthodontic pain was analyzed using Spearman's correlation analysis.

RESULTS

The maximum mean level of pain intensity occurred at 24 hours after bonding (53.31±16.13) and fell to normal levels at day 7. Spearman's correlation analysis found a moderate positive association between preoperative pain tolerance and self-reported pain after archwire placement (P<0.01). There was no significant difference in pain intensity between male and female patients at any time point (P>0.05).

CONCLUSION

A simple and noninvasive preoperative sensory test (the cold pressor test) was useful in predicting the risk of developing unbearable pain in patients after archwire placement. Self-reported pain after archwire placement decreased as individual pain tolerance increased.

Pain in cancer survivors

Cancer and its treatment exert a heavy psychological and physical toll. Of the myriad symptoms which result, pain is common, encountered in between 30% and 60% of cancer survivors. Pain in cancer survivors is a major and growing problem, impeding the recovery and rehabilitation of patients who have beaten cancer and negatively impacting on cancer patients' quality of life, work prospects and mental health. Persistent pain in cancer survivors remains challenging to treat successfully. Pain can arise both due to the underlying disease and the various treatments the patient has been subjected to. Chemotherapy causes painful chemotherapy-induced peripheral neuropathy (CIPN), radiotherapy can produce late effect radiation toxicity and surgery may lead to the development of persistent post-surgical pain syndromes. This review explores a selection of the common causes of persistent pain in cancer survivors, detailing our current understanding of the pathophysiology and outlining both the clinical manifestations of individual pain states and the treatment options available.

Conditioned pain modulation and situational pain catastrophizing as preoperative predictors of pain following chest wall surgery: a prospective observational cohort study

BACKGROUND

Variability in patients' postoperative pain experience and response to treatment challenges effective pain management. Variability in pain reflects individual differences in inhibitory pain modulation and psychological sensitivity, which in turn may be clinically relevant for the disposition to acquire pain. The aim of this study was to investigate the effects of conditioned pain modulation and situational pain catastrophizing on postoperative pain and pain persistency.

METHODS

Preoperatively, 42 healthy males undergoing funnel chest surgery completed the Spielberger's State-Trait Anxiety Inventory and Beck's Depression Inventory before undergoing a sequential conditioned pain modulation paradigm. Subsequently, the Pain Catastrophizing Scale was introduced and patients were instructed to reference the conditioning pain while answering. Ratings of movement-evoked pain and consumption of morphine equivalents were obtained during postoperative days 2-5. Pain was reevaluated at six months postoperatively.

RESULTS

Patients reporting persistent pain at six months follow-up (n = 15) were not significantly different from pain-free patients (n = 16) concerning preoperative conditioned pain modulation response (Z = 1.0, P = 0.3) or level of catastrophizing (Z = 0.4, P = 1.0). In the acute postoperative phase, situational pain catastrophizing predicted movement-evoked pain, independently of anxiety and depression (β = 1.0, P = 0.007) whereas conditioned pain modulation predicted morphine consumption (β = -0.005, P = 0.001).

CONCLUSIONS

Preoperative conditioned pain modulation and situational pain catastrophizing were not associated with the development of persistent postoperative pain following funnel chest repair. Secondary outcome analyses indicated that conditioned pain modulation predicted morphine consumption and situational pain catastrophizing predicted movement-evoked pain intensity in the acute postoperative phase. These findings may have important implications for developing strategies to treat or prevent acute postoperative pain in selected patients. Pain may be predicted and the malfunctioning pain inhibition mechanism as tested with CPM may be treated with suitable drugs augmenting descending inhibition.