Sex differences in the incidence of severe pain events following surgery: a review of 333,000 pain scores

Impact of Body Mass Index on Postoperative Pain and Opioid Administration After Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC)

PURPOSE

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a new surgical technique, developed for the treatment of peritoneal carcinomatosis (PC). In this retrospective observational study we assessed the impact of body mass index (BMI) on postoperative pain and opioid consumption.

METHODS

We analyzed pain scores after 100 PIPAC procedures using either oxaliplatin or doxorubicin-cisplatin performed in 49 patients with PC between July 2016 and September 2020. The patients were divided into 3 groups (BMI <18.5, 18.5 ≥ BMI < 25, BMI≥25). Pain was self-rated on a visual analogue scale (VAS) from 0 to 10.

RESULTS

Univariate logistic regression analysis identified oxaliplatin and PCI score to be associated with moderate to severe pain (VAS 4-10 at 8 am D1) after adjustment on BMI (OR [95% CI]; 3.26[1.00 - 10.65] p=0.050) and (OR [95% CI]; 1.09[1.01 - 1.17] p=0.019). The level of pain appeared significantly different between the treatment groups (median 2.5[0; 5] vs 0[0; 2.5] p=0.0017) irrespective of BMI (p =0.705 and p=0.118). Multivariate logistic regression analysis identified moderate to severe pain and synchronous PC to be associated with greater use of opioids (OR [95% CI]: 3.91 [1.24 - 12.32]) and (OR [95% CI]: 5.16 [1.71 - 15.58]; respectively. Opioids were administered after 45 procedures (45%) and was comparable between the treatment groups. Opioid administration and length-of-stay were similar among BMI bands.

CONCLUSION

BMI is not related to postoperative pain or opioid use, howevermoderate to severe pain and synchronous PC are factors associated with requiring opioids.

Pain After Outpatient Surgical Procedures

BACKGROUND

Approximately 8.1 million outpatient surgical procedures were performed in Germany in 2021. Little is known about the quality of postoperative pain treatment in the outpatient sector.

METHODS

The AQS1 project comprises a combined survey of patients and staff in the framework of quality control for ambulatory surgery. The primary endpoint of this study was the prevalence of relevant incisional pain (≥ 4/10 on the numerical rating scale) up to postoperative day 3. Secondary endpoints included prognostic variables for pain and pain-associated outcomes, based on the AQS1 patient questionnaire. Moreover, mixed regression models were used to analyze potential prognostic variables and associations of pain with other outcomes (study registration number DRKS00028052).

RESULTS

Data from 330 008 patients were evaluated (from 1 July 2001 to 31 December 2021). The overall prevalence of relevant incisional pain up to postoperative day 3 was 22.5%, with major differences between different types of procedure (3.2%-51.2%). Pain was most common after hemorrhoid surgery (51.2%) and the laparoscopic lysis of large and small bowel adhesions (45.4%). The main associations of relevant pain were with younger age (odds ratio [OR] 1.87, 95% confidence interval [1.82; 1.91]), early postoperative pain (1.34, [1.30; 1.39]), inadequate provision of analgesics (2.90, [2.71; 3.09]), and surgical wound infections (2.60, [2.43; 2.78]). Patients with pain reported lower overall satisfaction with the procedure and a longer inability to work.

CONCLUSION

These data have not been tested for representativeness. They can serve as a point of departure for the optimization of individualized perioperative pain therapy and for the planning of prospective studies.

Factors associated with the use of traditional doses of amitriptyline for chronic pain management: A cross-sectional study

There are studies on the effect of low-dose amitriptyline on pain control, but there is a lack of studies on the use of amitriptyline for chronic pain and the factors associated with the prescription of traditional doses. We used a national sample cohort of patients aged ≥ 18 years who were prescribed amitriptyline along with chronic pain, without psychiatric disorders, between 2002 to 2015. We categorized the prescriptions into 2 groups according to the daily dose: low doses (≤25 mg) and traditional doses (>25 mg). Multivariable logistic regression models were used to identify factors associated with traditional dose prescriptions. Among 177,769 prescriptions for amitriptyline, 15,119 (8.5%) were prescribed for chronic pain. The prevalence of prescriptions and proportion of traditional doses of amitriptyline tended to decrease during the study period. Male sex (odds ratio [OR] 1.09, 95% confidence interval [CI] 1.05-1.13); age 65-80 years (OR 1.12, 95% CI 1.08-1.16), especially ≥ 80 years (OR 1.55, 95% CI 1.45-1.65); headaches (OR 1.18, 95% CI 1.10-1.27), receiving medical aids (OR 2.58, 95% CI 2.46-2.71); and being prescribed benzodiazepines or zolpidem concomitantly (OR 1.10, 95% CI 1.06-1.15) were significantly associated with traditional dose prescriptions of amitriptyline. Although traditional dose prescriptions of amitriptyline have been declining, close monitoring is still required in the presence of the above-mentioned factors.

Inpatient pain alleviation after orthopaedic trauma surgery-are we doing a good job?

PURPOSE

Poor pain alleviation (PPA) after orthopaedic surgery is known to increase recovery time, readmissions, patient dissatisfaction, and lead to chronic postsurgical pain. This study's goal was to identify the magnitude of PPA and its risk factors in the orthopaedic trauma patient population.

METHODS

A single-institution's electronic medical records from 2015 to 2018 were available for retrospective analysis. Inclusion criteria included orthopaedic fracture surgery patients admitted to the hospital for 24 h or more. Collected variables included surgery type, basic demographics, comorbidities, inpatient medications, pain scores, and length of stay. PPA was defined as a pain score of ≥ 8 on at least three occasions 4-12 h apart. Associations between collected variables and PPA were derived using a multivariable logistic regression model and expressed in adjusted odds ratios.

RESULTS

A total of 1663 patients underwent fracture surgeries from 2015 to 2018, and 25% of them reported PPA. Female sex, previous use of narcotics, increased ASA, increased baseline pain score, and younger age without comorbidities were identified as significant risk factors for PPA. Spine procedures were associated with increased risk of PPA, while procedures in the hip, shoulder, and knee had reduced risk. Patients experiencing PPA were less likely to receive NSAIDs compared to other pain medications.

CONCLUSIONS

This study found an unacceptably high rate of PPA after fracture surgery. While the identified risk factors for PPA were all non-modifiable, our results highlight the necessity to improve application of current multimodal approaches to pain alleviation including a more personalized approach to pain alleviation.

Risk Factors for Severe Pain and Impairment of Daily Life Activities after Cesarean Section-A Prospective Multi-Center Study of 11,932 Patients

Cesarean section (CS) is the most widely performed and one of the most painful surgeries. This study investigated postoperative pain after CS using patient-related outcomes (PROs) to identify risk factors for severe pain. The secondary outcome was to evaluate the influence of surgery indication (primary CS (PCS) vs. urgent CS (UCS)). This multi-center, prospective cohort study included data submitted to the pain registry "quality improvement in postoperative pain treatment" (QUIPS) between 2010 and 2020. In total, 11,932 patients were evaluated. Median of maximal pain was 7.0 (numeric rating scale (NRS) 0 to 10); 53.9% suffered from severe pain (NRS ≥ 7), this being related to impairment of mood, ambulation, deep breathing and sleep, as well as more vertigo, nausea and tiredness (p < 0.001). Distraction, relaxation, mobilization, having conversations, patient-controlled analgesia (PCA) and pain monitoring were shown to be protective for severe pain (p < 0.001). Maximal pain in PCS and UCS was similar, but UCS obtained more analgesics (p < 0.001), and experienced more impairment of ambulation (p < 0.001) and deep breathing (p < 0.05). Severe pain has a major effect on daily-life activities and recovery after CS, and depends on modifiable factors. More effort is needed to improve the quality of care after CS.

Tapentadol Immediate Release (IR) versus Morphine Hydrochloride for Postoperative Analgesia of Patients Undergoing Total Abdominal Hysterectomy-A Prospective Cohort Study

Background and Objectives: This study aimed to examine the efficacy of tapentadol immediate release (IR) and morphine hydrochloride in the treatment of acute postoperative pain after total abdominal hysterectomy, as well as to examine the frequency of opioid-related side effects in observed patients. Materials and Methods: The prospective observational study was conducted over five months, and it included a total number of 100 patients. The two cohorts had different types of postoperative analgesia, and the effects were observed for 24 h postoperatively, by following the pain scores on NRS (Numerical Pain Scale), contentment with analgesia, and opioid-related side effects. Results: Statistical significance was found when assessing pain 24 h after surgery while coughing, where patients in the tapentadol IR group had significantly higher mean pain scores (p < 0.01). The subjective feeling of satisfaction with postoperative analgesia was statistically significant in the tapentadol IR group (p = 0.005). Vertigo appeared significantly more in patients from the morphine group (p = 0.03). Conclusions: Tapentadol IR (immediate release) and morphine hydrochloride are both effective analgesics used in the first 24 h after total transabdominal hysterectomy. Overall satisfaction of patients with analgesia was good. The frequency of side effects was higher in the morphine group, with statistical significance regarding the vertigo.

Postoperative pain-related outcomes and perioperative pain management in China: a population-based study

Background

Postoperative pain poses a significant challenge to the healthcare system and patient satisfaction and is associated with chronic pain and long-term narcotic use. However, systemic assessment of the quality of postoperative pain management in China remains unavailable.

Methods

In this cross-sectional study, we analyzed data collected from a nationwide registry, China Acute Postoperative Pain Study (CAPOPS), between September 2019 and August 2021. Patients aged 18 years or above were required to complete a self-reported pain outcome questionnaire on the first postoperative day (POD1). Perioperative pain management and pain-related outcomes, including the severity of pain, adverse events caused by pain or pain management, and perception of care and satisfaction with pain management were analyzed.

Findings

A total of 26,193 adult patients were enrolled. There were 48.7% of patients who had moderate-to-severe pain on the first day after surgery, and pain severity was associated with poor recovery and patient satisfaction. The systemic opioid use was 68% on the first day after surgery, and 89% of them were used with intravenous patient-controlled analgesia, while the rate of postoperative nerve blocks was low.

Interpretation

Currently, almost half of patients still suffer from moderate-to-severe pain after surgery in China. The relatively high rate of systemic opioid use and low rate of nerve blocks used after surgery suggests that more effort is needed to improve the management of acute postoperative pain in China.

Funding

National Key Research and Development Program of China (No. 2018YFC2001905).

Flexible ureteroscopic lithotripsy with a suctioning ureteral access sheath for removing upper urinary calculi under local anesthesia

Objectives

We aimed to probe the safety and effectiveness of flexible ureteroscopic lithotripsy (FURL) with a suctioning ureteral access sheath (S-UAS) for removing upper urinary calculi under local anesthesia (LA).

Materials and methods

The clinical data of 56 patients with upper urinary calculi treated by FURL with an S-UAS under LA during the period between September 2019 and November 2022 were analyzed retrospectively. For LA, intramuscular pethidine (1.0-2.0 mg/kg) and phenergan (25 mg) were administered 30 min prior to surgery, and oxybuprocaine hydrochloride gel was administered through the urethra at the start of the surgery. The S-UAS and flexible ureteroscope were used for FURL. Demographic characteristics, stone-related parameters, and clinical outcomes were analyzed.

Result

A total of 66 procedures were performed successfully on 46 patients (Group A), who underwent unilateral surgeries, and on 10 patients (Group B) who underwent same-session bilateral surgeries. All 56 patients were operated upon without altering the anesthesia strategy, and none required additional analgesia. The mean stone sizes of the Group A and Group B patients were 20.24 ± 5.45 mm and 29.40 ± 3.89 mm, respectively. The mean operative times of the two groups were 53.04 ± 13.35 min and 90.00 ± 15.81 min, respectively. In Group A, the stone-free rates (SFRs) were 76.1% (35/46) and 85.1% (40/46) at postoperative day 1 and day 30, respectively. In Group B, the SFRs were 80.0% (16/20) and 85.0% (17/20), respectively. Four (8.7%) patients in Group A suffered complications such as fever, stent pain, urosepsis, and steinstrasse. In Group B, one (10%) patient suffered from fever.

Conclusion

FURL, combined with an S-UAS under LA, is a feasible option and provides satisfactory clinical outcomes for appropriately selected patients.

Post-operative pain following percutaneous nephrolithotripsy- clinical correlates

OBJECTIVES

Management of postoperative pain following percutaneous nephrolithotripsy (PCNL) is a significant goal. We sought to identify risk factors and clinical correlates of postoperative pain in order to improve perioperative management and patient satisfaction.

MATERIALS AND METHODS

A single-center, retrospective analysis, from a prospectively maintained database, of all consecutive patients who underwent PCNL for renal calculi between January 2011 and August 2018. Postoperative pain was assessed using the visual analog scale (VAS) and analgesic use. We considered VAS score above 4 as meaningful. Pain management was standardized according to patirnt reported VAS scores. Multivariable logistic regression was performed to identify risk factors and clinical correlates.

RESULTS

A total of 496 patients were analyzed. Younger age was associated with VAS above 4 on the operative day and the first postoperative following PCNL (p = 0.003 and p < 0.001, respectively). Female gender was associated with VAS above 4 in the first 2 days following the operation (p < 0.001).

CONCLUSIONS

Younger age and female gender would most likely benefit from pre-emptive improved pain management protocols following PCNL.

Intraoperative Esketamine Is Effective at Reducing Acute Postoperative Pain in Bariatric Surgery Patients: a Randomized Control Trial

BACKGROUND

The analgesic effect and postoperative effects of esketamine are not yet clear in bariatric surgeries. Many bariatric surgery patients suffer from acute abdominal pain after surgery which leads to increased opioid use. This study aimed to determine whether intraoperative use of esketamine could reduce acute postoperative pain in bariatric surgery patients.

METHODS

We designed a randomized double-blinded controlled trial. Included patients between the ages of 18 and 50 years with a body mass index ≥27 kg/m2 and American Society of Anesthesiologists Physical Status of I-III, scheduled to undergo sleeve gastrectomy. We divided them into two groups, the control group which received a placebo, and the esketamine group which received a loading dose of esketamine 0.2 mg/kg and a maintenance dose of 0.2 mg/(kg·h) along with other anesthetic drugs during the surgery. After the surgery, they were assessed for Numerical Rating Scale (NRS) pain scores and Post Operative Nausea and Vomiting (PONV) scores, while other surgical data were recorded during the surgery.

RESULTS

We enrolled 68 patients, 52 females, and 16 males. The 0.5 h, 1 h, 2 h, 6 h, and 12 h NRS scores were significantly lower in the esketamine group compared to the control group, and the extra painkillers administered were significantly lower in the esketamine group (p<0.05).

CONCLUSION

Intraoperative use of esketamine can reduce acute postoperative pain in bariatric surgery patients. Further studies should explore whether the reduced pain is due to the anti-depressive effect of esketamine or purely the analgesic effect.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (ChiCTR2100054038, https://www.chictr.org.cn/com/25/showproj.aspx?proj=142806 ).

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.

Assessment of postoperative pain after pressurized intraperitoneal aerosol chemotherapy (PIPAC) in the treatment of peritoneal metastasis

PURPOSE

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a new surgical technique, for the treatment of initially unresectable peritoneal metastasis (PM). Our objective was to assess postoperative pain and morbidity.

METHODS

Between July 2016 and September 2020, data from 100 consecutive PIPAC procedures with oxaliplatin (PIPAC Ox) or doxorubicin-cisplatin (PIPAC C/D) in 49 patients with PM (all etiologies) were analyzed. Pain was self-assessed using a visual analog scale (VAS) of 0-10.

RESULTS

The median PIPAC procedures per patient were 2 [1-3]. Patients indicated greatest pain at 4 pm on the day of the procedure (D0) and on postoperative D1 at 8 am and 4 pm. Postprocedural moderate-to-severe pain (VAS 4-10) was more frequent with PIPAC Ox than with PIPAC C/D, respectively 14 (36.8%) vs 7 (13.5%); p = 0.010. Hospitalization was longer for patients with moderate-to-severe pain than for others (median 4 days [3-7] vs 3 days [2-4], p = 0.004). Multivariate analysis identified oxaliplatin as a factor associated with greater pain (OR [95% CI], 2.95 [1.10-7.89]. Opiate administration was similar after PIPAC Ox and PIPAC C/D procedures, p = 0.477.

CONCLUSION

PIPAC was well-tolerated, and pain was well-controlled in the majority of patients. Pain was greatest at 4 pm on D0 and 8 am and 4 pm on D1. PIPAC Ox is associated with greater pain than PIPAC C/D, independently of opiate treatment. Moderate-to-severe pain was associated with longer hospital stays.

Global Research Trends of Gender-Related Artificial Intelligence in Medicine Between 2001-2020: A Bibliometric Study

This study aimed to assess the research on medical Artificial intelligence (AI) related to sex/gender and explore global research trends over the past 20 years. We searched the Web of Science (WoS) for gender-related medical AI publications from 2001 to 2020. We extracted the bibliometric data and calculated the annual growth of publications, Specialization Index, and Category Normalized Citation Impact. We also analyzed the publication distributions by institution, author, WoS subject category, and journal. A total of 3,110 papers were included in the bibliometric analysis. The number of publications continuously increased over time, with a steep increase between 2016 and 2020. The United States of America and Harvard University were the country and institution that had the largest number of publications. Surgery and urology nephrology were the most common subject categories of WoS. The most occurred keywords were machine learning, classification, risk, outcomes, diagnosis, and surgery. Despite increased interest, gender-related research is still low in medical AI field and further research is needed.

Acute postoperative pain in 23 procedures of gynaecological surgery analysed in a prospective open registry study on risk factors and consequences for the patient

Effective perioperative pain management is essential for optimal patient recovery after surgery and reduces the risk of chronification. However, in clinical practice, perioperative analgesic treatment still needs to be improved and data availability for evidence-based procedure specific analgesic recommendations is insufficient. We aimed to identify procedures related with high pain scores, to evaluate the effect of higher pain intensity on patients and to define patient and intervention related risk factors for increased pain after standard gynaecological and obstetrical surgery. Therefore, we performed a prospective cross-sectional study based on the German registry for quality in postoperative pain (QUIPS). A cohort of 2508 patients receiving surgery between January 2011 and February 2016 in our tertiary referral centre (university departments of gynaecology and obstetrics, respectively) answered a validated pain questionnaire on the first postoperative day. Maximal pain intensity was measured by means of a 11-point numeric rating scale (NRS) and related to procedure, perioperative care as well as patient characteristics. The interventions with the highest reported pain scores were laparoscopic removal of ovarian cysts (NRS of 6.41 ± 2.12) and caesarean section (NRS of 6.98 ± 2.08). Factors associated with higher pain intensity were younger age (OR 1.75, 95% CI 1.65-1.99), chronic pain (OR 2.08, 95% CI 1.65-2.64) and surgery performed outside the regular day shift (OR 1.67, 95% CI 1.09-2.36). Shorter duration of surgery, peridural or local analgesic and preoperative sedation reduced postoperative pain. Patients reporting high pain scores (NRS ≥ 5) showed relevant impairment of daily activities and reduced satisfaction. Caesarean section and minimal invasive procedures were associated with the highest pain scores in the present ranking. Pain management of these procedures has to be reconsidered. Younger age, receiving surgery outside of the regular shifts, chronic pain and the surgical approach itself have a relevant influence on postoperative pain intensity. When reporting pain scores of 5 or more, patients were more likely to have perioperative complications like nausea or vomiting and to be impaired in mobilisation. Registry-based data are useful to identify patients, procedures and critical situations in daily clinical routine, which increase the risk for elevated post-intervention pain. Furthermore, it provides a database for evaluation of new pain management strategies.

Effectiveness of a Peer-Led Pain Management Program in Relieving Chronic Pain and Enhancing Pain Self-Efficacy Among Older Adults: A Clustered Randomized Controlled Trial

Chronic pain is common in nursing home residents, who may have difficulty seeking out pain management strategies. Peer support model show promise as a strategy for managing chronic conditions. This was a clustered randomized controlled trial. A peer-led pain management program was provided for the experimental group. Pain situation, depression, quality of life, non-drug strategies used, and pain knowledge were measured. A total of 262 participants joined the study (146 were allocated as experimental group and 116 as control group). Before our intervention, the mean pain score reported was as high as 6.36 on a 10-point Likert Scale. The high intensity of their pain very much interfered with the daily activities of the participants. Pain interference was high and the participants had poor coping as indicated by the low pain self-efficacy. Depression and a low quality of life score was found. Upon completion of our PAP, there was a significant increase in pain self-efficacy, pain interference as well as quality of life for the participants in the experimental group and not in the control group, and this improvement sustained in 3-month follow up. The present study used a peer support models and proven to be effective in managing pain and pain related situations for nursing home residents with chronic pain. The peer volunteers involved in the pain management program taught relevant pain knowledge and pain management strategies to help our participants.

Clinical Trial Registration:https://clinicaltrials.gov/ct2/show/NCT03823495, NCT03823495.

Sex differences in the consumption of over-the-counter analgesics among amateur volleyball players

Background

Compared with the normal adult population, athletes of several sport disciplines, such as endurance sports, ball sports, cycling and swimming, have higher use of over-the-counter analgesics (OTC analgesics). The aim of this study was to describe the epidemiology of OTC analgesic use in volleyball players as a typical competitive sport discipline. One particular focus was placed on the analysis whether the athletes’ use of OTC analgesics was influenced by their performance motivation.

Methods

A cross-sectional survey among amateur volleyball players was carried out using a web-based sports questionnaire. The study included athletes of both sexes, 18 years and older, currently playing in a German volleyball league. The athletes’ sport-related complaints were evaluated regarding the use of OTC analgesics. The use of OTC analgesics by athletes was compared with their performance motivation, based on the „Achievement Motives Scale - Sport” (AMS-Sport) questionnaire.

Results

The analysis of 114 completed questionnaires of amateur athletes revealed that the use of OTC analgesics was sex dependent, with a higher prevalence of use in female players (60%) versus male players (38%). The main reasons for consumption of OTC analgesics were pain in the head, knee and shoulder. The most frequently taken drug was ibuprofen, most often taken at competitions and over a period of 4 years (median). The analysis of the AMS-Sport questionnaire revealed that a logistic regression model for estimating the probability of drug use can be explained by the factors hope of success and years of playing practise in female players but not male players. In females, an increase in the factor hope of success resulted in a lower probability of OTC analgesic use, while an increase in years of playing practise resulted in a higher probability of use.

Conclusion

The average duration that volleyball players in this study took OTC analgesics was higher than that of the German population, and OTC analgesic use was more prevalent in female than male volleyball players. Thus, to reduce the prevalence of OTC analgesic use, educational programs should be implemented in sports teams; and, to reduce direct and indirect social pressure, sports teams should also receive sex-specific psychological support.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13102-021-00273-5.

Enhanced Recovery After Surgery Reduces Postoperative Opioid Use and 90-Day Readmission Rates After Open Thoracolumbar Fusion for Adult Degenerative Deformity

BACKGROUND

The role of enhanced recovery after surgery (ERAS) pathways implementation has not been previously explored in adult deformity patients.

OBJECTIVE

To determine the impact of ERAS pathways implementation in adult patients undergoing open thoraco-lumbar-pelvic fusion for degenerative scoliosis on postoperative outcome, opioid consumption, and unplanned readmission rates.

METHODS

In this retrospective single-center study, we included 124 consecutive patients who underwent open thoraco-lumbar-pelvic fusion from October 2016 to February 2019 for degenerative scoliosis. Primary outcomes consisted of postoperative supplementary opioid consumption in morphine equivalent dose (MED), postoperative complications, and readmission rates within the postoperative 90-d window.

RESULTS

There were 67 patients in the ERAS group, and 57 patients served as pre-ERAS controls. Average patient age was 69 yr. The groups had comparable demographic and intraoperative variables. ERAS patients had a significantly lower rate of postoperative supplemental opioid consumption (248.05 vs 314.05 MED, P = .04), a lower rate of urinary retention requiring catheterization (5.97% vs 19.3%, P = .024) and of severe constipation (1.49% vs 31.57%, P < .0001), and fewer readmissions after their surgery (2.98% vs 28.07%, P = .0001).

CONCLUSION

A comprehensive multidisciplinary approach to complex spine surgery can reduce opioid intake, postoperative urinary retention and severe constipation, and unplanned 90-d readmissions in the elderly adult population.

Patient and Procedural Determinants of Postoperative Pain Trajectories

BACKGROUND

The primary goal of this study was to evaluate patterns in acute postoperative pain in a mixed surgical patient cohort with the hypothesis that there would be heterogeneity in these patterns.

METHODS

This study included 360 patients from a mixed surgical cohort whose pain was measured across postoperative days 1 through 7. Pain was characterized using the Brief Pain Inventory. Primary analysis used group-based trajectory modeling to estimate trajectories/patterns of postoperative pain. Secondary analysis examined associations between sociodemographic, clinical, and behavioral patient factors and pain trajectories.

RESULTS

Five distinct postoperative pain trajectories were identified. Many patients (167 of 360, 46%) were in the moderate-to-high pain group, followed by the moderate-to-low (88 of 360, 24%), high (58 of 360, 17%), low (25 of 360, 7%), and decreasing (21 of 360, 6%) pain groups. Lower age (odds ratio, 0.94; 95% CI, 0.91 to 0.99), female sex (odds ratio, 6.5; 95% CI, 1.49 to 15.6), higher anxiety (odds ratio, 1.08; 95% CI, 1.01 to 1.14), and more pain behaviors (odds ratio, 1.10; 95% CI, 1.02 to 1.18) were related to increased likelihood of being in the high pain trajectory in multivariable analysis. Preoperative and intraoperative opioids were not associated with postoperative pain trajectories. Pain trajectory group was, however, associated with postoperative opioid use (P < 0.001), with the high pain group (249.5 oral morphine milligram equivalents) requiring four times more opioids than the low pain group (60.0 oral morphine milligram equivalents).

CONCLUSIONS

There are multiple distinct acute postoperative pain intensity trajectories, with 63% of patients reporting stable and sustained high or moderate-to-high pain over the first 7 days after surgery. These postoperative pain trajectories were predominantly defined by patient factors and not surgical factors.

EDITOR’S PERSPECTIVE

Efficacy of methylprednisolone on pain, trismus and quality of life following surgical removal of mandibular third molars: a double-blind, split-mouth, randomised controlled trial

Background

The objective of the present study was to compare the efficacy of different doses of methylprednisolone on postoperative sequelae and quality of life (QoL) following surgical removal of mandibular third molars (SRM3).

Material and Methods

Fifty-two patients (16 men and 36 women, mean age 25.9 years, range: 18-39) with bilateral impacted mandibular third molars were randomly allocated into intraoperative muscular injection of either 20mg, 30mg, 40mg methylprednisolone or saline injection. Baseline measurements were obtained preoperatively and compared with assessment after one day, three days, seven days and one month. Pain and trismus were estimated by visual analog scale score and interincisal mouth opening, respectively. Subjective assessment of QoL included Oral Health Impact Profile (OHIP-14). Descriptive and generalized estimating equation analyses were made and expressed as mean values with a 95% confidence interval.

Results

Methylprednisolone revealed no significant differences in pain, trismus and QoL compared with placebo. Higher prevalence of postoperative pain and worsening in QoL were observed with increased age (P=0.00). Smoking and increased time of surgery decreased mouth opening in the early healing phase (P=0.00).

Conclusions

The present study revealed no significant improvement of methylprednisolone on postoperative sequelae and QoL following SRM3 compared with placebo.

Key words:Corticosteroids, dentistry, mandible, methylprednisolone, pain, third molar, trismus.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

SIGNIFICANCE

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

Evaluating the association of preoperative parecoxib with acute pain trajectories after video-assisted thoracoscopic surgery: a single-centre cohort study in Taiwan

OBJECTIVE

The efficacy of parecoxib as pre-emptive analgesia still remains controversial. This study aimed to investigate how pre-emptive analgesia with parecoxib affected postoperative pain trajectories over time in patients undergoing thoracic surgery.

DESIGN

Retrospective cohort study.

SETTING

A single medical centre in Taiwan.

PARTICIPANTS

We collected 515 patients undergoing video-assisted thoracoscopic surgery at a tertiary medical centre between September 2016 and August 2017.

INTERVENTIONS

Pre-emptive parecoxib before surgery.

PRIMARY AND SECONDARY OUTCOME MEASURES

Daily numeric rating pain scores in the first postoperative week.

RESULTS

A total of 196 (38.1%) of the recruited patients received parecoxib preoperatively. The latent curve analysis revealed that woman, higher body weight and postoperative use of parecoxib were associated with increased baseline level of pain scores over time (p=0.035, 0.005 and 0.048, respectively) but epidural analgesia and preoperative use of parecoxib were inclined to decrease it (both p<0.001). Regarding the decreasing trends of changes in daily pain scores, older age and epidural analgesia tended to steepen the slope (p=0.014 and <0.001, respectively). Preoperative use of parecoxib were also related to decreased frequency of rescue morphine medication (HR=0.4; 95% CI 0.25 to 0.65).

CONCLUSIONS

Pre-emptive analgesia with parecoxib was associated with decreased baseline pain scores but had no connection with pain decreasing trends over time. Latent curve analysis provided insights into the dynamic relationships among the analgesic modalities, patient characteristics and postoperative pain trajectories.

OPRM1 and COMT polymorphisms: implications on postoperative acute, chronic and experimental pain after cardiac surgery

Aim: Investigate the potential role of OPRM1 (mu-opioid receptor) and COMT (catechol-O-methyltransferase enzyme) polymorphisms in postoperative acute, chronic and experimental thermal pain. Methods: A secondary analysis of 125 adult cardiac surgery patients that were randomized between fentanyl and remifentanil during surgery and genotyped. Results: Patients in the fentanyl group with the COMT high-pain sensitivity haplotype required less postoperative morphine compared with the average-pain sensitivity haplotype (19.4 [16.5; 23.0] vs 34.6 [26.2; 41.4]; p = 0.00768), but not to the low-pain sensitivity group (30.1 [19.1; 37.7]; p = 0.13). No association was found between COMT haplotype and other pain outcomes or OPRM1 polymorphisms and the different pain modalities. Conclusion: COMT haplotype appears to explain part of the variability in acute postoperative pain in adult cardiac surgery patients.

Sex and gender differences in anesthesia: Relevant also for perioperative safety?

Sex (a biological determination) and gender (a social construct) are not interchangeable terms and both impact perioperative management and patient safety. Sex and gender differences in clinical phenotypes of chronic illnesses and risk factors for perioperative morbidity and mortality are relevant for preoperative evaluation and optimization. Sex-related differences in physiology, as well as in pharmacokinetics and pharmacodynamics of anesthetic drugs may influence the anesthesia plan, the management of pain, postoperative recovery, adverse effects, patient satisfaction, and outcomes. Further studies are needed to characterize outcome differences between men and women in non-cardiac, cardiac, and transplantation surgery in order to individualize perioperative management and improve patient safety. Transgender patients represent a vulnerable population who need special perioperative care. Gender balance increases team performance and may improve perioperative outcomes.

Gender Differences in Postoperative Pain, Nausea and Vomiting After Elective Laparoscopic Cholecystectomy

BACKGROUND

Although reports suggest that pain and postoperative nausea and vomiting (PONV) may be more frequent in women, the evidence is inconsistent. The objective of this study was to investigate whether women are more sensitive to pain and PONV after laparoscopic cholecystectomy (LC).

METHODS

A total of 370 women and 275 men were included in a retrospective cohort study. All underwent LC under standardized general anesthesia. The variables analyzed included clinical and anthropometric parameters. End points were the incidence of nausea, vomiting, pain, and the requirement for additional pain relievers and antiemetics to control these.

RESULTS

The women were younger and had lower body weight than the men (p < 0.001). Body mass index was within the normal range for 50% of women and 30% of men (p < 0.001). Pain was more common in women at 1, 6, 12 and 24 h after surgery (p < 0.02). Narcotics in addition to the doses used to lessen pain intensity (p = 0.01) were required in 60 women and 19 men (p < 0.001). PONV was more frequent in women at 1 and 6 h after surgery (p < 0.01). Rescue antiemetics were required in 35 women and 11 men (p = 0.008). Hospital stay was shorter for men (p < 0.001). Four patients in each group developed postoperative complications (p = 0.14). There was no mortality.

CONCLUSIONS

Early postoperative pain, nausea and vomiting after LC were more common in women, who more frequently required analgesic and antiemetic rescue medication.

Sex Comparisons in Opioid Use and Pain After Colorectal Surgery Using Enhanced Recovery Protocols

BACKGROUND

Differences in nociception and use of opioids between sexes are of particular interest, considering higher rates of persistent opioid use among women after surgery. Although enhanced recovery protocols (ERPs) have improved postoperative pain control in colorectal surgery, sex-based comparisons of inpatient opioid use after surgery in an ERP remain understudied.

METHODS

This retrospective study analyzed data from adults after colorectal surgery using an ERP at a single hospital between 2015 and 2017. The main outcome was the rate of opioid consumption measured as oral morphine equivalents per inpatient day. Poisson regression determined association between sex and opioid consumption, accounting for early discharge, using inverse probability weighting and adjusting for covariates that retained significance on univariate analysis. Linear regression assessed the association between sex and pain scores on postoperative days 0-5 adjusting for covariates.

RESULTS

Of 588 patients included, 43% were men and 57% were women. In the unadjusted model, malignancy, prehospital psychiatric medication and analgesic use, tobacco, ileostomy creation, operative time, and postoperative complications were associated with increased opioid consumption. In multivariate analyses, prehospital opioid and nonopioid analgesic use, operative time, anastomotic leak, and postoperative ileus remained significantly associated with increased inpatient opioid consumption. However, there was no significant association between sex and opioid use in crude or adjusted analysis (incidence rate ratio: 1.09; 95% confidence interval: 0.90, 1.32). Women reported higher average daily pain scores (coefficient: 0.29; 95% confidence interval: 0.04, 0.55) in adjusted analyses.

CONCLUSIONS

Among patients undergoing colorectal surgery using an ERP, sex-based differences exist in pain scores but not early postoperative opioid consumption. Identification of intragroup differences in postoperative pain and opioid use among patients managed with an ERP serves as targets for customization and enhancement of current protocols. Furthermore, incongruence between reported pain and analgesic administration may have important implications for sex-related differences in persistent opioid use.

Antinociceptive and Immune Effects of Delta-9-Tetrahydrocannabinol or Cannabidiol in Male Versus Female Rats with Persistent Inflammatory Pain

Chronic pain is the most common reason reported for using medical cannabis. The goal of this research was to determine whether the two primary phytocannabinoids, delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), are effective treatments for persistent inflammatory pain. In experiment 1, inflammation was induced by intraplantar injection of Complete Freund's adjuvant (CFA). Then THC (0.0-4.0 mg/kg, i.p.) or CBD (0.0-10 mg/kg, i.p.) was administered twice daily for 3 days. On day 4, THC, CBD, or vehicle was administered, and allodynia, hyperalgesia, weight-bearing, locomotor activity, and hindpaw edema were assessed 0.5-4 hours postinjection. In experiment 2, CFA or mineral oil (no-pain control)-treated rats were given THC (2.0 mg/kg, i.p.), CBD (10 mg/kg, i.p.), or vehicle in the same manner as in experiment 1. Four hours postinjection on day 4, serum samples were taken for analysis of cytokines known to influence inflammatory pain: interleukin (IL)-1β, IL-6, IL-10, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α THC dose-dependently reduced pain-related behaviors but did not reduce hindpaw edema, and little tolerance developed to THC's effects. In contrast, CBD effects on inflammatory pain were minimal. THC produced little to no change in serum cytokines, whereas CBD decreased IL-1β, IL-10, and IFN-γ and increased IL-6. Few sex differences in antinociception or immune modulation were observed with either drug, but CFA-induced immune activation was significantly greater in males than females. These results suggest that THC may be more beneficial than CBD for reducing inflammatory pain in that THC maintains its efficacy with short-term treatment in both sexes and does not induce immune activation. SIGNIFICANCE STATEMENT: The pain-relieving effects of cannabidiol (CBD) and delta-9-tetrahydrocannabinol (THC) are examined in male and female rats with persistent inflammatory pain to determine whether individual phytocannabinoids could be a viable treatment for men and women with chronic inflammatory pain. Additionally, sex differences in the immune response to an adjuvant and to THC and CBD are characterized to provide preliminary insight into immune-related effects of cannabinoid-based therapy for pain.

Postoperative pain after colorectal surgery

PURPOSE

Postoperative pain is a keystone in perioperative programs, as pain negatively impacts recovery. This study aimed to evaluate pain after elective colorectal surgery and to identify risk factors for postoperative pain.

METHODS

This prospective cohort study comprised consecutive patients undergoing elective colorectal surgery within the Enhanced Recovery after Surgery (ERAS) perioperative program between March 2013 and April 2017. The numeric rating scale (NRS) was used to estimate maximum pain. Logistic regression was used to model associations with the type of surgery, age, gender, and comorbidities.

RESULTS

The cohort comprised 434 of 459 eligible patients. On the day of surgery to postoperative day 3, 50-64% of patients reported moderate to severe pain (NRS 4-10). Postoperative pain was similar for open and minimally invasive rectal surgery, while patients undergoing minimally invasive colonic surgery experienced more pain on the day of surgery and less pain on postoperative days 2 and 3 vs. open colonic surgery. Younger age was associated with more pain every postoperative day and by 0.7 NRS/10 years (95% CI 0.5-0.9, P < 0.001) on the day of surgery, while having diabetes type 2 was associated with less postoperative pain by - 1.3 NRS (95% CI - 2.4 to - 0.2) on the day of surgery.

CONCLUSIONS

The majority, and young patients in particular, experience moderate to severe pain after open and minimally invasive colorectal surgery, despite following ERAS perioperative program. There is a need for effective and individualized analgesia after colorectal surgery, since the individual pain response to surgery is difficult to predict.

Is There an Impact of Sex on Acute Postthoracotomy Pain? A Retrospective Analysis

BACKGROUND

Current knowledge about sex-related differences states that pain is generally more frequent and intense in women. Because severe postthoracotomy pain is associated with complications, sufficient pain control is essential. Data on sex-related aspects in the context of pain after thoracotomy are scarce. The study attempted to determine whether sex significantly affects pain and pain treatment after thoracotomy.

METHODS

This retrospective study assessed visual analogue scale (VAS) scores and analgesic consumption (opioids and diclofenac) during the first 5 days after surgery and the point in time when analgesics were changed from the intravenous to the oral route in patients who had open lung surgery. The influences of sex, PCEA (patient-controlled epidural analgesia), age, and surgical factors were evaluated with mixed-model analysis.

RESULTS

The study was able to include 344 patients (130 female, 214 male). The VAS scores model did not consider sex as relevant. The opioid model showed a PCEA-time-sex interaction with increasing opioid demand after day 3 that predominantly affected male patients (P < .001). Diclofenac doses where significantly higher in an interaction of female sex and small extent of surgery (P = .007). Posterolateral thoracotomy led to significantly higher VAS scores (P < .001) and higher demand for opioids (P = .007) and diclofenac (P = .012).

CONCLUSIONS

The study concluded that there are no general sex-related differences in pain intensity and analgesic requirement after thoracotomy. Anterolateral thoracotomy was the less painful surgical approach. PCEA had favorable results, although there seemed to a rebound pain phenomenon after epidural catheter removal on postoperative day 3 that mainly affected male patients.

Is topical lidocaine beneficial before catheter insertion in esophageal manometry and ambulatory pH monitoring?

BACKGROUND

Conventionally, topical anesthesia is applied to improve the tolerance of esophageal manometry (EM) and ambulatory pH monitoring (apH) but there is presently no evidence supporting this practice. We aimed to compare the tolerance of EM and apH with vs without topical lidocaine anesthesia.

METHODS

A prospective study was conducted at our center between January 2017 and January 2019. All patients who underwent EM or apH and completed a systematically distributed standardized patient survey were included. From January 2017 to June 2018, all patients had a viscous lidocaine solution applied before EM and apH ("lidocaine" group). After June 2018, we ceased applying any topical anesthesia ("no lidocaine" group). Patient-reported adverse effects and satisfaction scores were compared between these two patient groups.

KEY RESULTS

Two hundred forty-nine patient surveys were included. "Lidocaine" (n = 124) and "no lidocaine" (n = 125) groups were similar in age (56.9 ± 14.0 vs 56.0 ± 13.7; P = .77) and gender distributions (65.9% vs 63.3% female; P = .68). Patients in the "lidocaine" group were less likely to report pain during catheter insertion (33.6% vs 50.8%; P = .007, OR: 0.49 [95% CI 0.29-0.83]) and reported a lower overall pain score (2.82 ± 1.38 vs 3.20 ± 1.42 on 5; P = .04). There was a tendency toward increased global satisfaction with lidocaine application but that was not statistically significant (4.36 ± 1.05 vs 4.11 ± 1.13; P = .08). In subgroup analyses, female patients, younger patients, and patients who underwent EM were more likely to benefit from lidocaine application.

CONCLUSIONS AND INFERENCES

Application of topical lidocaine before esophageal motility tests reduces pain during catheter insertion and overall pain.

Preoperative predictors of poor acute postoperative pain control: a systematic review and meta-analysis

OBJECTIVES

Inadequate postoperative pain control is common and is associated with poor clinical outcomes. This study aimed to identify preoperative predictors of poor postoperative pain control in adults undergoing inpatient surgery.

DESIGN

Systematic review and meta-analysis DATA SOURCES: MEDLINE, Embase, CINAHL and PsycINFO were searched through October 2017.

ELIGIBILITY CRITERIA

Studies in any language were included if they evaluated postoperative pain using a validated instrument in adults (≥18 years) and reported a measure of association between poor postoperative pain control (defined by study authors) and at least one preoperative predictor during the hospital stay.

DATA EXTRACTION AND SYNTHESIS

Two reviewers screened articles, extracted data and assessed study quality. Measures of association for each preoperative predictor were pooled using random effects models.

RESULTS

Thirty-three studies representing 53 362 patients were included in this review. Significant preoperative predictors of poor postoperative pain control included younger age (OR 1.18 [95% CI 1.05 to 1.32], number of studies, n=14), female sex (OR 1.29 [95% CI 1.17 to 1.43], n=20), smoking (OR 1.33 [95% CI 1.09 to 1.61], n=9), history of depressive symptoms (OR 1.71 [95% CI 1.32 to 2.22], n=8), history of anxiety symptoms (OR 1.22 [95% CI 1.09 to 1.36], n=10), sleep difficulties (OR 2.32 [95% CI 1.46 to 3.69], n=2), higher body mass index (OR 1.02 [95% CI 1.01 to 1.03], n=2), presence of preoperative pain (OR 1.21 [95% CI 1.10 to 1.32], n=13) and use of preoperative analgesia (OR 1.54 [95% CI 1.18 to 2.03], n=6). Pain catastrophising, American Society of Anesthesiologists status, chronic pain, marital status, socioeconomic status, education, surgical history, preoperative pressure pain tolerance and orthopaedic surgery (vs abdominal surgery) were not associated with increased odds of poor pain control. Study quality was generally high, although appropriate blinding of predictor during outcome ascertainment was often limited.

CONCLUSIONS

Nine predictors of poor postoperative pain control were identified. These should be recognised as potentially important factors when developing discipline-specific clinical care pathways to improve pain outcomes and to guide future surgical pain research.

PROSPERO REGISTRATION NUMBER

CRD42017080682.

A prospective study of patients’ pain intensity after cardiac surgery and a qualitative review: effects of examiners’ gender on patient reporting

Background and aims

As indicated by experimental studies, reports of pain intensity may depend on the examiner’s gender. Until now, it is unclear whether this is relevant in clinical routine. This study investigated prospectively whether the gender of assessor plays a role in patients’ pain reports and whether this role differs in male and female patients.

Methods

165 patients (66.4 years±0.63; 118 males) scheduled for heart surgery were allocated consecutively to one examiner out of four students of both genders: two females and two males (aged 24.3 years±1.7). Therefore, the following study groups were defined: Group 1: female assessors-female patients, 2: female-male; 3: male-female, 4: male-male. Using a standardized analgesic scheme, patients were asked to rank their pain intensity on a numeric rating scale (NRS: 0–10), postoperatively. Statistics: Kruskal-Wallis, Mann-Whitney; p<0.05. Additionally, a qualitative literature review of the databases Medline and CENTRAL was performed focusing on experimental and clinical studies on experimenter gender bias. Due to the review, this prospective clinical study was designed to investigate whether patients after surgery report lower pain intensities when assessed by a female compared to a male assessor.

Results

Summarizing all patients, pain intensity on POD_1 was rated 4.0±2.4 on NRS and decreased on POD_2 to 3.0±2.1 [H(3)=37.941, p=0.000]. On average, pain intensity did not differ between males and females (NRS: 3.5 vs. 3.6). Only on the second postoperative day, more intense pain was reported in front of female assessors and less intense pain in front of male assessors (NRS: 3.4 vs. 2.4; p=0.000). A main effect for the four groups was seen (p=0.003): male patients reported higher pain scores to female assessors (NRS: 3.5 vs. 2.3; p=0.000).

Conclusions

Together, contrary to the expectations, patients after cardiac surgery reported a higher pain intensity in front of a female and a lower pain intensity in front of a male assessor. In particular, female caregivers may heighten the reported pain intensity up to 1.2 NRS-points; this bias seems to be more relevant for male patients.

Implications

Therefore, despite some methodological weakness, our data suggest that attention should be paid to a rather small, but somehow significant and consistent examiner gender bias after cardiac surgery especially in male patients. Further clinical studies are needed to show the true extent of clinical relevance and exact mechanisms underlying these gender reporting bias.

Preemptive Caffeine Administration Blocks the Increase in Postoperative Pain Caused by Previous Sleep Loss in the Rat: A Potential Role for Preoptic Adenosine A2A Receptors in Sleep-Pain Interactions

Sleep and pain are reciprocally related, but the precise mechanisms underlying this relationship are poorly understood. This study used a rat model of surgical pain to examine the effect of previous sleep loss on postoperative pain and tested the hypothesis that preoptic adenosinergic mechanisms regulate sleep-pain interactions. Relative to ad libitum sleep, 6 hours of total sleep deprivation prior to a surgical incision significantly enhanced postoperative mechanical hypersensitivity in the affected paw and prolonged the time to recovery from surgery. There were no sex-specific differences in these measures. There were also no changes in adrenocorticotropic hormone and corticosterone levels after sleep deprivation, suggesting that this effect was not mediated by the stress associated with the sleep perturbation. Systemic administration of the nonselective adenosine receptor antagonist caffeine at the onset of sleep deprivation prevented the sleep deprivation-induced increase in postoperative hypersensitivity. Microinjection of the adenosine A2A receptor antagonist ZM 241385 into the median preoptic nucleus (MnPO) blocked the increase in surgical pain levels and duration caused by prior sleep deprivation and eliminated the thermal hyperalgesia induced by sleep deprivation in a group of nonoperated (i.e., without surgical incision) rats. These data show that even a brief sleep disturbance prior to surgery worsens postoperative pain and are consistent with our hypothesis that adenosine A2A receptors in the MnPO contribute to regulate these sleep-pain interactions.

Characterizations of Temporal Postoperative Pain Signatures With Symbolic Aggregate Approximations

OBJECTIVES

The primary aim was to characterize the temporal dynamics of postoperative pain intensity using symbolic aggregate approximation (SAX). The secondary aim was to explore the effects of sociodemographic and clinical factors on the SAX representations of postoperative pain intensity.

MATERIALS AND METHODS

We applied SAX to a large-scale time series database of 226,808 acute postoperative pain intensity ratings. Pain scores were stratified by patient age, sex, type of surgery, home opioid use, and postoperative day (POD), and costratified by age and sex. Cosine similarity, a metric that measures distance using vector angle, was applied to these motif data to compare pain behavior similarities across strata.

RESULTS

Across age groups, SAX clusters revealed a shift from low-to-low pain score transitions in older patients to high-to-high pain score transitions in younger patients, whereas analyses stratified by sex showed that males had a greater focus of pain score transitions among lower-intensity pain scores compared with females. Surgical stratification, using cardiovascular surgery as a reference, demonstrated that pulmonary surgery had the highest cosine similarity at 0.855. With POD stratification, POD 7 carried the greatest cosine similarity to POD 0 (0.611) after POD 1 (0.765), with POD 3 (0.419) and POD 4 (0.441) carrying the lowest cosine similarities with POD 0.

DISCUSSION

SAX offers a feasible and effective framework for characterizing large-scale postoperative pain within the time domain. Stratification of SAX representations demonstrate unique temporal dynamic profiles on the basis of age group, sex, type of surgery, preoperative opioid use, and across PODs 1 to 7.

Acute pain and peripheral sensitization following cautery disbudding in 1- and 4-week-old calves

Acute pain and peripheral sensitization development after cautery disbudding was investigated in 33 calves administered preventive multimodal analgesia. The animals were assigned randomly to three groups: 1) Group SH (Control), undergoing sham disbudding at 1 and 4weeks of age; 2) Group ED (Early Disbudding), undergoing disbudding at 1week of age and sham disbudding at 4weeks of age; 3) Group LD (Late Disbudding), undergoing sham disbudding at 1week of age and disbudding at 4weeks of age. Physiological parameters (heart rate, respiratory rate, rectal temperature, invasive blood pressure, cortisol, β-endorphin, interleukin-1β, interleukin-6, tumor necrosis factor-α and haptoglobin plasmatic concentration), local variables (tactile sensitivity score, pressure pain thresholds and horn temperature), behavior and pain scores [multidimensional pain scale and visual analogue scale (VAS)] were assessed at baseline and at several pre-determined time points until 24h after disbudding. Tactile sensitivity score significantly and equally increased in both groups ED and LD and pressure pain thresholds significantly decreased in group LD until 24h after disbudding compared to group SH. Pain and VAS scores significantly and equally increased in both groups ED and LD until 24h after disbudding compared to group SH. No significant differences in physiological parameters, behavior and horn temperature were detected among groups. The present study suggests that acute pain and peripheral sensitization develop and do not differ in calves disbudded at 1week and 4weeks of age. Moreover, the use of physiological and behavioral parameters as sole indicators of acute pain might lead to improper conclusions and should be reassessed.

Predictors of Cold and Pressure Pain Tolerance in Healthy South African Adults

Background

Studies on relationships between sex, ethnicity, and pain have largely emanated from the United States and Europe. We compared cold (CPT) and pressure pain tolerance (PPT) in male and female South Africans of African and European ancestry and assessed whether psychosocial factors (including pain beliefs) predicted differences in pain tolerance.

Methods

We recruited 106 (62 female) students of African ancestry and 106 (55 female) of European ancestry and subjected them to a cold-pressor test and pressure algometry. Socioeconomic status (SES), pain catastrophizing, depression, anxiety, and pain beliefs were assessed as predictors of pain tolerance.

Results

CPT was lower in students of African compared with European ancestry (for both sexes), and PPT was lower in female than male students (for both ethnicities). Females were very accepting of men expressing pain and males less so. Males of African ancestry were least accepting but still tolerant. Multivariate analysis identified African ancestry, and particularly being a female of African ancestry, as strong predictors of lower CPT. Anxiety was a weak predict or of CPT. Sex was the only strong predictor of PPT on multivariate analysis (PPT females < males), and catastrophizing was a weak predictor. Female sex and African ancestry were strong predictors of acceptance of expression of pain in males. SES was a weak predictor of the Appropriate Pain Behavior Questionnaire-Malescore.

Conclusions

Despite different cultural and social backgrounds from US and European cohorts, we saw similar patterns of sex and ethnic differences in CPT and PPT in an African cohort. Traditional psychosocial predictors of pain sensitivity predicted variation in the outcome variables but were not strong predictors.

Factors associated with postoperative pain after retrograde intrarenal surgery for kidney stones

OBJECTIVE

We aimed to investigate factors related to early postoperative pain after retrograde intrarenal surgery (RIRS).

MATERIAL AND METHODS

A prospective data analysis of 250 patients who underwent RIRS due to kidney stones was performed. Postoperative pain was evaluated in all patients by using visual analogue scale (VAS). Patients with severe pain (VAS score ≥7) were separated and included in Group I (n=46). While patients without pain or with insignificant pain were included in Group II (n=204). The impact of patient-related (age, gender, renal anomalies, shock wave lithotripsy history, preoperative hydronephrosis) stone-related (stone number, side, size, location and opacity) and operation-related (preoperative and postoperative ureteral J-stenting, ureteral injury, postoperative bleeding and fever, stone-free rates, size of access sheath, and sheath indwelling time) factors on early stage postoperative pain (if any) were investigated.

RESULTS

Female gender increased the risk for pain 3.6-fold (p<0.05). One millimeter increase in stone diameter increased the risk for postoperative pain 1.15-fold. Prolonged sheath time was another important factor which increased the risk for pain (p<0.05). Patients with high residual fragments were also prone to early postoperative pain.

CONCLUSION

According to our results, patient-, stone-and operation-related factors associated with postoperative pain after RIRS were female gender, stone size and sheath time.

Impact of Gender Disparities on Short-Term and Long-Term Patient Reported Outcomes and Satisfaction Measures After Elective Lumbar Spine Surgery: A Single Institutional Study of 384 Patients

BACKGROUND

There is a paucity of data determining the impact that gender disparities have on spine outcomes, particularly perception of health and satisfaction. The aim of this study was to determine whether there is a difference in 3-month and 1-year patient-reported outcomes and satisfaction after elective lumbar spine surgery.

METHODS

This was a retrospectively analyzed study from a maintained prospective database of 384 patients who underwent elective lumbar spine surgery. Patients were categorized by gender (men, n = 199; women, n = 185). Patient-reported outcome instruments (Oswestry disability index, visual analogue scale-back pain/leg pain, EuroQol visual analogue scale, and EuroQol 5 dimensions questionnaire) were completed before surgery, then at 3 and 12 months after surgery along with patient satisfaction measures.

RESULTS

Baseline patient demographics, comorbidities, and operative variables were similar between both cohorts. The female cohort had a slightly longer hospital stay than male cohort (P = 0.007). Baseline patient-reported outcome measures were different between both cohorts, with female patients having more Oswestry disability index (23.8 vs. 20.4; P ≤ 0.0001) and visual analogue scale-back pain (7.2 vs. 6.2; P = 0.0004), and a lower EuroQol 5 dimensions questionnaire (0.34 vs. 0.49; P = 0.0001) compared with the male cohort. At 1-year follow-up, the male cohort had a significantly more mean change in visual analogue scale-leg pain (-3.9 vs. -2.8; P = 0.04) and trended to have more mean change in visual analogue scale-back pain (-3.4 vs. -2.5; P = 0.06) and EuroQol visual analogue scale (8.6 vs. 3.4; P = 0.054) scores compared with the female cohort. At 1-year a significantly more portion in the male cohort found that surgery met their expectations compared with the female cohort (65.0% vs. 49.5%; P = 0.02).

CONCLUSIONS

Our study suggests that there may be differences in perception of health, pain, and disability between men and women at baseline, short-term and long-term follow-up that may influence overall patient satisfaction.

Age and preoperative pain are major confounders for sex differences in postoperative pain outcome: A prospective database analysis

Objectives

Current literature is in disagreement regarding female sex as a risk factor for pain after surgery. We hypothesized, that sex differences exist but that they are influenced by certain factors. Here, we investigated the influence of sex for different clinically relevant postoperative pain (POP) outcome parameters and evaluated the role of assumed confounders for sex differences.

Methods

From 1372 screened patients undergoing orthopedic surgery at the university hospital of Muenster between March 2010 and June 2011, 890 patients were included. The validated International Pain Outcomes questionnaire was used to assess the role of sex for several aspects of POP including pain severity, physical and emotional functional interference as well as the patient’s perceptions of the care they received on the first day after surgery. Assessed confounders were age, preoperative chronic pain, anesthetic technique employed and surgical procedure. All statistical analyses were performed with SPSS Statistics Software 22.

Results

Linear regression analysis demonstrated that sex was a statistically significant risk factor for “worst pain since surgery”. Additionally, significant sex differences in “time spent in severe pain”, “feeling anxious due to pain”, “feeling helpless due to pain” and “opioid consumption since surgery” could be identified. An univariate general linear model showed that “age” and “preoperative pain” were significant confounders for sex differences. Further descriptive subgroup analysis revealed consistent sex differences for several POP outcome variables especially in patients older than 50 years or patients with preoperative chronic pain. However, sex differences disappeared in younger patients and in patients without preoperative pain.

Discussion

Our data confirmed that sex differences exist in pain intensity and frequency, pain interference with feelings and opioid consumption during the first 24 hours postoperatively. However, sex differences were significantly influenced by the factors “age” and “preoperative pain”. These findings may in part explain why clinical studies get different results related to sex differences and renders specific awareness in older women and female patients with preoperative chronic pain.

Sensitivity to Pain Traumatization Scale: development, validation, and preliminary findings

Background

This article reports three studies describing the development and validation of the 12-item Sensitivity to Pain Traumatization Scale (SPTS-12). SPT refers to the anxiety-related cognitive, emotional, and behavioral reactions to pain that resemble the features of a traumatic stress reaction.

Methods

In Study 1, a preliminary set of 79 items was administered to 116 participants. The data were analyzed by using combined nonparametric and parametric item response theory resulting in a 12-item scale with a one-factor structure and good preliminary psychometric properties. Studies 2 and 3 assessed the factor structure and psychometric properties of the SPTS-12 in a community sample of 823 participants (268 with chronic pain and 555 pain-free) and a clinical sample of 345 patients (126 with chronic post-surgical pain, 92 with other nonsurgical chronic pain, and 127 with no chronic pain) at least 6 months after undergoing coronary artery bypass graft surgery, respectively.

Results

The final SPTS-12 derived from Study 1 comprised 12 items that discriminated between individuals with different levels of SPT, with the overall scale showing good to very good reliability and validity. The results from Studies 2 and 3 revealed a one-factor structure for chronic pain and pain-free samples, excellent reliability and concurrent validity, and moderate convergent and discriminant validity.

Conclusion

The results of the three studies provide preliminary evidence for the validity and reliability of the SPTS-12.

Markov chain evaluation of acute postoperative pain transition states

Previous investigations on acute postoperative pain dynamicity have focused on daily pain assessments, and so were unable to examine intraday variations in acute pain intensity. We analyzed 476,108 postoperative acute pain intensity ratings, which were clinically documented on postoperative days 1 to 7 from 8346 surgical patients using Markov chain modeling to describe how patients are likely to transition from one pain state to another in a probabilistic fashion. The Markov chain was found to be irreducible and positive recurrent, with no absorbing states. Transition probabilities ranged from 0.0031, for the transition from state 10 to state 1, to 0.69 for the transition from state 0 to state 0. The greatest density of transitions was noted in the diagonal region of the transition matrix, suggesting that patients were generally most likely to transition to the same pain state as their current state. There were also slightly increased probability densities in transitioning to a state of asleep or 0 from the current state. An examination of the number of steps required to traverse from a particular first pain score to a target state suggested that overall, fewer steps were required to reach a state of 0 (range 6.1-8.8 steps) or asleep (range 9.1-11) than were required to reach a mild pain intensity state. Our results suggest that using Markov chains is a feasible method for describing probabilistic postoperative pain trajectories, pointing toward the possibility of using Markov decision processes to model sequential interactions between pain intensity ratings, and postoperative analgesic interventions.

Prevalence and characteristics of chronic body pain in China: a national study

Background

Chinese citizens regularly experience some form of bodily pain, yet little is known regarding the epidemiology of pain.

Methods

We conducted a nationally representative sample cross sectional study to estimate the prevalence of pain and identify risk factors of pain among 19,665 community residents aged 18–65 years in China. The China Sub-optimal Health Survey (CSHS) data was used to estimate pain prevalence. Body pain was also estimated by self-reports from the sample population. A logistical regression model was applied to estimate the odds ratio and 95 % CIs of acute pain and chronic pain to explore the potential risk factors.

Results

Women had a higher prevalence of pain than men (39.92 vs. 32.17 % for chronic pain). The prevalence of pain increased with age (29.72 % for ages 18–25 vs. 42.23 % for ages 45–65). The most common complaints were head, neck/shoulder, and waist/back pain. Females (OR 1.57, 95 % CI 1.44–1.71) ages 25 or older (25–45: OR 1.19, 95 % CI 1.04–1.36; 45–65: OR 1.47, 95 % CI 1.26–1.73) were more likely to report having chronic pain. Subjects’ living areas, and their drinking status (OR 1.32, 95 % CI 1.13–1.53) or smoking status (OR 1.01, 95 % CI 0.91–1.11), were also factors that were significantly associated with increased reporting of chronic pain.

Conclusion

Women had a higher prevalence of chronic pain than men, although both sexes had a high prevalence for chronic pain. There were significant differences between the two sexes and the location of chronic pain in the body, most notably in the shoulders, stomach, abdomen, and waist.

Inter-Hospital Variability of Postoperative Pain after Tonsillectomy: Prospective Registry-Based Multicentre Cohort Study

Objectives

Although tonsillectomy is one of the most frequent and painful surgeries, the association between baseline and process parameters and postoperative pain are not fully understood.

Methods

A multicentre prospective cohort study using a web-based registry enrolled 1,527 women and 1,008 men aged 4 to 85 years from 52 German hospitals between 2006 and 2015. Maximal pain (MP) score the first day after surgery on a numeric rating scale (NRS) from 0 (no pain) to 10 (MP) was the main outcome parameter.

Results

The mean maximal pain score was 5.8±2.2 (median 6). Multivariable analysis revealed that female gender (Odds ratio [OR] = 1.33; 95% confidence interval [CI] = 1.12 to 1.56; p = 0.001), age <20 years (OR = 1.56; CI = 1.27 to 1.91; p<0.0001), no pain counselling (OR = 1.78; CI = 1.370 to 2.316; p<0.001), chronic pain (OR = 1.34; CI = 1.107 to 1.64; p = 0.004), and receiving opioids in recovery room (OR = 1.89; CI = 1.55 to 2.325; p<0.001) or on ward (OR = 1.79; CI = 1.42 to 2.27; p<0.001) were independently associated with higher experienced maximal postoperative pain (greater the median of 6). The effect of age on pain was not linear. Maximal pain increased in underage patients to a peak at the age of 18 to 20 years. From the age of ≥20 years on, maximal pain after tonsillectomy continuously decreased. Even after adjustment to all statistically important baseline and process parameters, there was substantial variability of maximal pain between hospitals with a heterogeneity variance of 0.31.

Conclusion

Many patients seem to receive insufficient or ineffective analgesia after tonsillectomy. Further research should address if populations at risk of higher postoperative pain such as females, younger patients or those with preexisting pain might profit from a special pain management protocol. Beyond classical demographical and process parameters the large variability between different hospitals is striking and indicates the existence of other unknown factors influencing postoperative pain after tonsillectomy.

Clinically derived early postoperative pain trajectories differ by age, sex, and type of surgery

The objective of this study was to determine the effects of age, sex, and type of surgery on postoperative pain trajectories derived in a clinical setting from pain assessments in the first 24 hours after surgery. This study is a retrospective cohort study using a large electronic medical records system to collect and analyze surgical case data. The sample population included adult patients undergoing nonambulatory nonobstetric surgery in a single institution over a 1-year period. Analyses of postoperative pain trajectories were performed using a linear mixed-effects model. Pain score observations (91,708) from 7293 patients were included in the statistical analysis. On average, the pain score decreased about 0.042 (95% confidence interval [CI]: -0.044 to -0.040) points on the numerical rating scale (NRS) per hour after surgery for the first 24 postoperative hours. The pain score reported by male patients was approximately 0.27 (95% CI: -0.380 to -0.168) NRS points lower than that reported by females. Pain scores significantly decreased over time in all age groups, with a slightly more rapid decrease for younger patients. Pain trajectories differed by anatomic location of surgery, ranging from -0.054 (95% CI: -0.062 to -0.046) NRS units per hour for integumentary and nervous surgery to -0.104 (95% CI: -0.110 to -0.098) NRS units per hour for digestive surgery, and a positive trajectory (0.02 [95% CI: 0.016 to 0.024] NRS units per hour) for musculoskeletal surgery. Our data support the important role of time after surgery in considering the influence of biopsychosocial and clinical factors on acute postoperative pain.

Associations between psychological variables and pain in experimental pain models. A systematic review

BACKGROUND

The association between pain and psychological characteristics has been widely debated. Thus, it remains unclear whether an individual's psychological profile influences a particular pain experience, or if previous pain experience contributes to a certain psychological profile. Translational studies performed in healthy volunteers may provide knowledge concerning psychological factors in healthy individuals as well as basic pain physiology. The aim of this review was to investigate whether psychological vulnerability or specific psychological variables in healthy volunteers are predictive of the level of pain following experimental pain models.

METHODS

A systematic search on the databases, PubMed, Embase, Cochcrane library, and Clinicaltrials.gov was performed during September 2014. All trials investigating the association between psychological variables and experimental pain in healthy volunteers were considered for inclusion.

RESULTS

Twenty-nine trials met the inclusion criteria, with a total of 2637 healthy volunteers. The included trials investigated a total of 45 different psychological tests and 27 different types of pain models. The retrieved trials did not present a sufficiently homogenous group to perform meta-analysis. The collected results were diverse. A total of 16 trials suggested that psychological factors may predict the level of pain, seven studies found divergent results, and six studies found no significant association between psychological variables and experimental pain.

CONCLUSION

Psychological factors may have predictive value when investigating experimental pain. However, due to substantial heterogeneity and methodological shortcomings of the published literature, firm conclusions are not possible.

Efficacy of Tramadol as a Sole Analgesic for Postoperative Pain in Male and Female Mice

Tramadol is a centrally acting weak μ opioid agonist that has few of the adverse side effects common to other opioids. Little work has been done to establish an effective analgesic dose of tramadol specific for surgical laparotomy and visceral manipulation in mice. We used general appearance parameters to score positive indicators of pain including posture, coat condition, activity, breathing, and interactions with other mice, activity events (that is, the number of times each mouse stretched up in a 3-min period) used as an indicator of decreased pain, von Frey fibers, and plasma levels of corticosterone to determine whether tramadol at 20, 40, or 80 mg/kg prevented postoperative pain in male and female C57BL/6 mice. A ventral midline laparotomy with typhlectomy was used as a model of postoperative pain. In male mice, none of the markers differed between groups that received tramadol (regardless of dose) and the saline-treated controls. However, general appearance scores and plasma corticosterone levels were lower in female mice that received 80 mg/kg tramadol compared with saline. In summary, for severe postoperative pain after laparotomy and aseptic typhlectomy, tramadol was ineffective in male C57BL/6 mice at all doses tested. Although 80 mg/kg ameliorated postoperative pain in female C57BL/6 mice, this dose is very close to the threshold reported to cause toxic side effects, such as tremors and seizures. Therefore, we do not recommend the use of tramadol as a sole analgesic in this mouse model of postoperative pain.