Persistent postsurgical pain in a general population: prevalence and predictors in the Tromsø study

Chronic postsurgical pain: A European survey

BACKGROUND

Chronic postsurgical pain (CPSP) is a clinical problem, and large prospective studies are needed to determine its incidence, characteristics, and risk factors.

OBJECTIVE

To find predictive factors for CPSP in an international survey.

DESIGN

Observational study.

SETTING

Multicentre European prospective observational trial.

PATIENTS

Patients undergoing breast cancer surgery, sternotomy, endometriosis surgery, or total knee arthroplasty (TKA).

METHOD

Standardised questionnaires were completed by the patients at 1, 3, and 7 days, and at 1, 3, and 6 months after surgery, with follow-up via E-mail, telephone, or interview.

MAIN OUTCOME MEASURE

The primary goal of NIT-1 was to propose a scoring system to predict those patient likely to have CPSP at 6 months after surgery.

RESULTS

A total of 3297 patients were included from 18 hospitals across Europe and 2494 patients were followed-up for 6 months. The mean incidence of CPSP at 6 months was 10.5%, with variations depending on the type of surgery: sternotomy 6.9%, breast surgery 7.4%, TKA 12.9%, endometriosis 16.2%. At 6 months, neuropathic characteristics were frequent for all types of surgery: sternotomy 33.3%, breast surgery 67.6%, TKA 42.4%, endometriosis 41.4%. One-third of patients experienced CPSP at both 3 and 6 months. Pre-operative pain was frequent for TKA (leg pain) and endometriosis (abdomen) and its frequency and intensity were reduced after surgery. Severe CPSP and a neuropathic pain component decreased psychological and functional wellbeing as well as quality of life. No overarching CPSP risk factors were identified.

CONCLUSION

Unfortunately, our findings do not offer a new CPSP predictive score. However, we present reliable new data on the incidence, characteristics, and consequences of CPSP from a large European survey. Interesting new data on the time course of CPSP, its neuropathic pain component, and CPSP after endometriosis surgery generate new hypotheses but need to be confirmed by further research.

TRIAL REGISTRATION

clinicaltrials.gov ID: NCT03834922.

Postoperative Pain Following Eye Enucleation: A Prospective Observational Study

Background and Objectives: Enucleation of an eye is the most invasive procedure in ophthalmologic surgery. It can be the result of various diseases (malignant/chronic/trauma/infection) and is nevertheless relatively rare, but leads to the loss of a strongly innervated neuronal organ. This study systematically evaluates postoperative pain levels following enucleation of the eye globe. Materials and Methods: This prospective single-center study enrolled twenty-four patients undergoing enucleation of the eye globe. Perioperatively all patients completed (preoperative day, day of surgery, 1st, 2nd, and 3rd day following surgery) standardized questionnaires concerning their pain experience and treatment-related side-effects (internal protocol, QUIPS, painDETECT®). Patients received usual pain therapy in an unstandardized individual manner. Results: Preoperatively, mean average pain intensity of all included patients was 3.29 ± 2.46 (range, 0-8), 3.29 ± 3.24 (range, 0-8) on the day of surgery, 4.67 ± 1.90 (range, 2-10) on day 1, 3.25 ± 1.39 (range, 1-6) on day 2, and 2.71 ± 1.30 (range, 1-6) on day 3 after surgery. Mean maximum pain intensity was 4.71 ± 3.28 (range, 0-10) preoperatively, 4.04 ± 3.78 (range, 0-10) on the day of surgery, 5.75 ± 2.01 (range, 2-10) on day 1, 4.25 ± 1.89 (range, 2-10) on day 2, and 3.88 ± 1.54 (range, 2-8) on day 3 after surgery. Nineteen patients (79.2%) stated that they would have preferred more pain therapy. Conclusions: Patients undergoing eye enucleation report pain sensations in need of intervention in this university hospital. Thus, effective standardized pain treatment concepts are now a high priority to be established in an interdisciplinary manner containing standardized regimens and continuous regional procedures. Awareness of this problem in the medical team should be sharpened through targeted training and information.

Mechanisms of pain in aging and age-related conditions: Focus on caregivers

Pain is a complex, subjective experience that can significantly impact quality of life, particularly in aging individuals, by adversely affecting physical and emotional well-being. Whereas acute pain usually serves a protective function, chronic pain is a persistent pathological condition that contributes to functional deficits, cognitive decline, and emotional disturbances in the elderly. Despite substantial progress that has been made in characterizing age-related changes in pain, complete mechanistic details of pain processing mechanisms in the aging patient remain unknown. Pain is particularly under-recognized and under-managed in the elderly, especially among patients with Alzheimer's disease (AD), Alzheimer's disease-related dementias (ADRD), and other age-related conditions. Furthermore, difficulties in assessing pain in patients with AD/ADRD and other age-related conditions may contribute to the familial caregiver burden. The purpose of this article is to discuss the mechanisms and risk factors for chronic pain development and persistence, with a particular focus on age-related changes. Our article also highlights the importance of caregivers working with aging chronic pain patients, and emphasizes the urgent need for increased legislative awareness and improved pain management in these populations to substantially alleviate caregiver burden.

Trajectories of pain and opioid use up to one year after surgery: analysis of a European registry

BACKGROUND

Long-term opioid use after surgery is a crucial healthcare problem in North America. Data from European hospitals are scarce and differentiation of chronic pain has rarely been considered.

METHODS

In a mixed surgical cohort of the PAIN OUT registry, opioid use and chronic pain were evaluated before surgery, and 6 and 12 months after surgery (M6/M12). Subgroups with or without opioid medication and pre-existing chronic pain were analysed. M12-chronic pain was categorised as chronic postsurgical pain (CPSP) meeting the ICD-11 definition, chronic pain related to surgery not meeting the ICD-11 definition, and chronic pain unrelated to surgery. Primary endpoint was the rate of M12 opioid users. Variables associated with M12 opioid use and patient-reported outcomes were evaluated.

RESULTS

Of 2326 patients, 5.5% were preoperative opioid users; 4.4% and 3.5% took opioids at M6 and M12 (P<0.001). Chronic pain before operation and at M6/M12 was reported by 41.2%, 41.8%, and 34.7% of patients, respectively (P<0.001). The rate of M12 opioid users was highest in group unrelated (22.3%; related 8.3%, CPSP 1.5%; P<0.001). New opioid users were 1.1% (unrelated 7.1%, related 2.3%, CPSP 0.7%; P<0.001). M12 opioid users reported more pain, pain-related physical and affective interference, and needed more opioids than non-users. The predominant variable associated with M12 opioids was preoperative opioid use (estimated odds ratio [95% confidence interval]: 28.3 [14.1-56.7], P<0.001).

CONCLUSIONS

Opioid use was low in patients with CPSP, and more problematic in patients with chronic pain unrelated to surgery. A detailed assessment of chronic pain unrelated or related to surgery or CPSP is necessary.

CLINICAL TRIAL REGISTRATION

NCT02083835.

Cosmetic surgery and associated chronic postsurgical pain: A cross-sectional study from Norway

OBJECTIVES

Chronic postsurgical pain (CPSP) is a common postoperative sequela. Despite the increasing popularity of cosmetic surgeries, there is a notable lack of research on CPSP in this context, with existing studies focusing on breast surgeries only. To address existing gaps in knowledge, the objective of the present study was to investigate the self-reported prevalence of cosmetic surgery and associated CPSP among Norwegian adults.

METHODS

An online questionnaire consisting of three questions inquiring prior cosmetic surgeries, associated CPSP, and whether participants had sought for pain management was constructed and distributed among adults residing in Norway.

RESULTS

Between November 30, 2022 and December 16, 2022, 1,746 participants were recruited. 10% of respondents, 73.3% of which were female, affirmed to have undergone cosmetic surgery. About 1 in 4 of these was aged 18-29 years. The prevalence of CPSP was 12.6%. CPSP was five times more common among male, compared to female respondents. While about two thirds of participants indicating to have experienced CPSP were aged 18-29 years, CPSP was much less common among individuals of other ages.

CONCLUSION

Consistent with international trends, there appears to be a young and growing population of cosmetic surgery consumers in Norway. According to our results, about 1 in 8 of these might be affected by CPSP, a condition that is notoriously hard to treat and weighting heavily on public healthcare and social welfare systems. Large-scale longitudinal studies further investigating the topic are thus urgently needed.

The role of neuroinflammation in the transition of acute to chronic pain and the opioid-induced hyperalgesia and tolerance

Current evidence suggests that activation of glial and immune cells leads to increased production of proinflammatory mediators, creating a neuroinflammatory state. Neuroinflammation has been proven to be a fundamental mechanism in the genesis of acute pain and its transition to neuropathic and chronic pain. A noxious event that stimulates peripheral afferent nerve fibers may also activate pronociceptive receptors situated at the dorsal root ganglion and dorsal horn of the spinal cord, as well as peripheral glial cells, setting off the so-called peripheral sensitization and spreading neuroinflammation to the brain. Once activated, microglia produce cytokines, chemokines, and neuropeptides that can increase the sensitivity and firing properties of second-order neurons, upregulating the signaling of nociceptive information to the cerebral cortex. This process, known as central sensitization, is crucial for chronification of acute pain. Immune-neuronal interactions are also implicated in the lesser-known complex regulatory relationship between pain and opioids. Current evidence suggests that activated immune and glial cells can alter neuronal function, induce, and maintain pathological pain, and disrupt the analgesic effects of opioid drugs by contributing to the development of tolerance and dependence, even causing paradoxical hyperalgesia. Such alterations may occur when the neuronal environment is impacted by trauma, inflammation, and immune-derived molecules, or when opioids induce proinflammatory glial activation. Hence, understanding these intricate interactions may help in managing pain signaling and opioid efficacy beyond the classical pharmacological approach.

Does Immediate Long-Span Nerve Allograft Reconstruction Affect the Incidence of Chronic Postsurgical and Neuropathic Pain in the Reconstructed Mandible Following Resection for Benign and Malignant Disease

BACKGROUND

Peripheral nerve injury can lead to chronic postsurgical pain (CPSP) and neuropathic pain following major surgery.

PURPOSE

Determine in patients undergoing ablative mandibular operations with transection of the trigeminal nerve: do those who undergo immediate repair, when compared to those whose nerves are not repaired, have a decreased or increased risk for CPSP or post-traumatic trigeminal neuropathic pain (PTTNp)?

STUDY DESIGN, SETTING, SAMPLE

A multisite, retrospective cohort of patients who underwent resection of the mandible for benign or malignant disease with either no repair or immediate repair of the intentionally transected trigeminal nerve with a long-span nerve allograft were analyzed for the presence or absence of CPSP and PTTNp at 6 months.

PREDICTOR VARIABLE

The primary predictor was the immediate repair or no repair of the trigeminal nerve.

MAIN OUTCOME VARIABLE

The primary outcome was the presence or absence of CPSP and PTTNp at 6 months postsurgery.

COVARIATES

There were 13 covariate variables, including age, sex, ethnicity, nerve injury, type of PTTNp, malignant or benign pathology and subtypes of each, use of radiation or chemotherapy, treatment of transected nerve end, longest follow-up time, pain scale, and onset of pain.

ANALYSES

Two-tailed Student's t test and Welch's t test were performed on mean scores and post hoc logistics and linear regression modeling were performed when indicated. The confidence level for statistical significance was P value <.05.

RESULTS

There were 103 and 94 subjects in the immediate and no-repair groups, respectively. The incidence of CPSP in the no-repair group was 22.3% and PTTNp was 2.12%, while there was 3.8% CPSP and 0% PTTNp in the repair group, which was statistically significant (P = <.001). Logistic regression modeling showed a statistically significant inverse relationship between the immediate repair and the incidence of CPSP/PTTNp with an odds ratio of 0.43, 95% confidence interval 0.18 to 1.01, P = .05. Greater age, malignant pathology, and chemo/radiation treatments were covariates found more frequently in the no repair group.

CONCLUSION AND RELEVANCE

Immediate repair of an intentionally transected trigeminal nerve with a long-span nerve allograft during resection of the mandible for both benign and malignant disease appears to reduce CPSP and possibly eliminate the development of PTTNp.

Effect of Local Ketamine Subcutaneous Injection at the Incision Site in Reducing the Postoperative Pain Score after Transabdominal Hysterectomy

Background

Pain control after operations is essential in decreasing the patient recovery period and potential morbidity. Prescribing opiates is very effective, but significant side effects accompany them. This study aims to examine the effect of local ketamine infiltration in decreasing pain intensity in patients undergoing transabdominal hysterectomy.

Methods

In this double-blind, randomized, controlled clinical trial, a total of 92 patients undergoing transabdominal hysterectomy aged 30-60 years were selected and divided into two intervention and control groups randomly. For the intervention group, ketamine was injected subcutaneously into the incision site at a dose of 0.5 mg/kg after the operation. In the control group, 5 mg normal saline was used in the same method. Postoperative pain intensity was measured using the visual analog scale (VAS: 0-10). The pain score and dose of administered opioids were documented at 1, 2, 4, 6, 12, and 24 hours and compared between the two groups.

Results

Postoperative pain intensity was significantly lower in the intervention group than in the control group, except for hour 24. The mean amounts of administered opioids were significantly lower in the intervention group at hours 6 and 12, as well as the total amount of used opioids, and no significant side effects were documented.

Conclusion

Local ketamine subcutaneous injection in the incisional site is effective and is a safe procedure for reducing pain scores in patients who underwent a transabdominal hysterectomy.

Immediate postoperative topical lidocaine gel for the treatment of eye pain following corneal abrasion in descemet membrane endothelial keratoplasty (DMEK) under general anaesthesia: a pilot retrospective analysis

BACKGROUND

Patients undergoing corneal abrasion as part of Descemet membrane endothelial keratoplasty (DMEK) under general anesthesia suffer from early burning pain postoperatively. This pain appears to be poorly treatable with systemic analgesics. This study aims to evaluate postoperative pain management using topical lidocaine gel after DMEK with iatrogenic corneal abrasion.

METHODS

Retrospective analysis of 28 consecutive patients undergoing DMEK with corneal abrasion from October 19, 2021, to November 12, 2021, at a German university hospital. Patients during week 1 and 2 received peri-operative standard pain treatment (cohort S) and additional local lidocaine gel during week 3 and 4 immediately postoperatively (cohort L).

RESULTS

13 patients were included in cohort S and 15 patients in cohort L. At awakening all patients (100%) in cohort S reported burning pain, and six of 15 patients (40%) in cohort L reported burning pain. Burning pain scores were significantly lower in cohort L (p < 0.001 at awakening, p < 0.001 at 10 min, p < 0.001 at 20 min, p < 0.001 at 30 min, p = 0.007 at 40 min after awakening, and p < 0.001 at leaving recovery room). No significant differences between cohort S and cohort L were detected concerning surgical outcome during 1-month-follow-up (p = 0.901 for best corrected visual acuity).

CONCLUSION

Patients undergoing DMEK with corneal abrasion suffer significant pain in the recovery room. A single dose of topic lidocaine gel reduces the early postoperative burning pain sufficiently and does not affect the surgical outcome.

The Acute Perioperative Pain Service: Impact, Organization, and Future Directions

PURPOSE OF REVIEW

The Acute Perioperative Pain Service has been established as a relatively new but important concept and service in clinical patient care. Many surgical institutions have dedicated inpatient acute pain services with variable compositions. This review aims to investigate the purpose, clinical and economic implications, and future direction of the Acute Perioperative Pain Service (APPS).

RECENT FINDINGS

There is growing evidence of the multiple benefits of a dedicated APPS, especially pertaining to patients at higher risk of poorly controlled postoperative pain. Healthcare providers furthermore realize the importance of the perioperative pain management continuity of care, consisting of preoperative pain evaluations and post-discharge follow-up in an outpatient pain management setting, in coordination with the primary teams. The Transitional Pain Service (TPS) has emerged as the next step in this evolution and has been successfully implemented at various medical centers. With the growing number of surgical procedures and the increasing complexity of the patient population, effective management of acute postoperative pain continues to be challenging, despite ongoing advances in clinical care, analgesic modalities, and research. The APPS is becoming the clinical standard of care for managing postoperative pain, and its role continues to expand worldwide.

The mechanisms and management of persistent postsurgical pain

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

Prevalence and Characteristics of Persistent Postoperative Pain After Thoracic Surgery: A Systematic Review and Meta-Analysis

BACKGROUND

A systematic review and meta-analysis was conducted to investigate the prevalence and characteristics of persistent (≥3 months) postoperative pain (PPP) after thoracic surgery.

METHODS

For this purpose, Medline, Embase, and CINAHL databases were searched for the prevalence and characteristics of PPP after thoracic surgery from their inception to May 1, 2022. Random-effect meta-analysis was used to estimate pooled prevalence and characteristics.

RESULTS

We included 90 studies with 19,001 patients. At a median follow-up of 12 months, the pooled overall prevalence of PPP after thoracic surgery was 38.1% (95% confidence interval [CI], 34.1-42.3). Among patients with PPP, 40.6% (95% CI, 34.4-47.2) and 10.1% (95% CI, 6.8-14.8) experienced moderate-to-severe (rating scale ≥4/10) and severe (rating scale ≥7/10) PPP, respectively. Overall, 56.5% (95% CI, 44.3-67.9) of patients with PPP required opioid analgesic use, and 33.0% (95% CI, 22.5-44.3) showed a neuropathic component.

CONCLUSIONS

One in 3 thoracic surgery patients developed PPP. There is a need for adequate pain treatment and follow-up in patients undergoing thoracic surgery.

Effectiveness of Communication Strategies in the Management of Chronic Postsurgical Pain: Protocol for a Systematic Review and Meta-Analysis

Purpose

To describe the details of a systematic review to assess the current evidence about the efficacy of communication strategies on the prevention of chronic postsurgical pain (CPSP).

Methods

The protocol for this systematic review was based on the Cochrane Handbook methodology and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) recommendations. A systematic search of the literature on electronic databases Medline, Embase, Cochrane Library, CINAHL, PsycINFO, and Web of Science (from the inception to 19 June 2022) was carried out using predefined search terms to identify relevant studies. This review will include randomized clinical trials or observational studies. The search strategy consisted of keywords and index terms related to "clinician", "communication" or "post-surgical pain". Inclusion criteria are as follows: randomized clinical trials or observational studies using a parallel group design that assess the efficacy of communication interventions in patients undergoing surgery and that assess pain and pain-related disability. We considered interventions that included any type of written, verbal, and non-verbal communication in combination with other interventions or without. Control groups may include no communication intervention or another intervention distinctly different. We excluded studies with follow-up duration of less than 3 months, patients aged <18 years, and studies for which no reviewer had language proficiency (eg, Chinese, Korean). Descriptive statistics will be used to summarize quantitative findings. Meta-analysis will only be considered if at least three studies used the same outcome with comparable interventions, as we expect a wide heterogeneity of study population and settings.

Conclusion

This systematic review and meta-analysis will be an important source for clinicians and researchers to understand the influence of communication to prevent CPSP.

Study Registration

This protocol is registered with the International Prospective Register of Systematic Reviews (PROSPERO). Registration number: CRD42021241596.

A prospective study of chronic postsurgical pain in elderly patients: incidence, characteristics and risk factors

BACKGROUND

Due to the continued growth of surgical procedures in older adults and the significant impact of chronic postsurgical pain (CPSP), it is crucial to improve our understanding of the occurrence of CPSP as well as the appropriate prevention and treatment. We therefore conducted this study to determine the incidence, characteristics and risk factors of CPSP in elderly patients at both 3 and 6 months after surgery.

METHODS

Elderly patients (aged ≥ 60 years) undergoing elective surgery in our institution between April 2018 and March 2020 were prospectively enrolled in this study. Data on demographics, preoperative psychological well-being, intraoperative surgical and anesthesia management, and acute postoperative pain intensity were collected. At 3 and 6 months after surgery, patients received telephone interview and completed the questionnaires regarding chronic pain characteristics, analgesic consumption, and interference of the pain with activities of daily living (ADL).

RESULTS

A total of 1065 elderly patients were followed up for 6 postoperative months and included in final analysis. At 3 and 6 months after operation, the incidence of CPSP was 35.6% [95% confidence interval (95% CI) 32.7 - 38.8%] and 21.5% (95% CI 19.0% - 23.9%), respectively. CPSP cause negative impacts on patient's ADL and most particularly on mood. Neuropathic features were found in 45.1% of the patients with CPSP at 3 months. At 6 months, 31.0% of those with CPSP reported that the pain had neuropathic features. Preoperative anxiety [3 months: Odds ratio (OR) 2.244, 95% CI 1.693 to 2.973; 6 months: OR 2.397, 95% CI 1.745 to 3.294], preoperative depression (3 months: OR 1.709, 95% CI 1.292 to 2.261; 6 months: OR 1.565, 95% CI 1.136-2.156), orthopedic surgery (3 months: OR 1.927, 95% CI 1.112 to 3.341; 6 months: OR 2.484, 95% CI 1.220 to 5.061), higher pain severity on movement within postoperative 24 h (3 months: OR 1.317, 95% CI 1.191 to 1.457; 6 months: OR 1.317, 95% CI 1.177 to 1.475) were associated with a higher risk for CPSP independently at both 3 and 6 months after surgery.

CONCLUSIONS

CPSP is a common postoperative complication in elderly surgical patients. Preoperative anxiety and depression, orthopedic surgery, and greater intensity of acute postoperative pain on movement are associated with an increased risk for CPSP. It should be kept in mind that developing psychological interventions to reduce anxiety and depression and optimizing the management of acute postoperative pain will be effective in reducing the development of CPSP in this population.

Risk factors and protective factors of acute postoperative pain: an observational study at a German university hospital with cross-sectional and longitudinal inpatient data

OBJECTIVES

Surgical fear is one of the most important psychological risk factors for postoperative pain, but less is known about the contribution of protective factors. This study investigated somatic and psychological risk and resilience factors of postoperative pain and validated the German version of the Surgical Fear Questionnaire (SFQ).

SETTING

University Hospital of Marburg, Germany.

DESIGN

Single-centre observational study and cross-sectional validation study.

PARTICIPANTS

Data for validating the SFQ were obtained from a cross-sectional observational study (N=198, mean age 43.6 years, 58.8% female) with persons undergoing different kinds of elective surgery. A sample of N=196 (mean age 43.0 years, 45.4% female) undergoing elective (orthopaedic) surgery was analysed to investigate somatic and psychological predictors of relevant acute postsurgical pain (APSP).

OUTCOME MEASURES

Participants completed preoperative and postoperative assessments at postoperative days 1, 2 and 7. Presurgical pain, age, gender, pain expectation, surgical setting, physical status, anaesthesia, surgical fear, pain catastrophising, depression, optimism and self-efficacy were examined as predictors.

RESULTS

Confirmatory factor analysis confirmed the original two-factor structure of the SFQ. Correlation analyses indicated good convergent and divergent validity. Internal consistency (Cronbach's α) was between 0.85 and 0.89. Blockwise logistic regression analyses for the risk of APSP revealed outpatient setting, higher preoperative pain, younger age, more surgical fear and low dispositional optimism as significant predictors.

CONCLUSIONS

The German SFQ is a valid, reliable and economical instrument with which the important psychological predictor surgical fear can be assessed. Modifiable factors that increase the risk of postoperative pain were higher pain intensity before surgery and being fearful about negative consequences of the surgery whereas positive expectations seem to buffer against postsurgical pain.

TRIAL REGISTRATION NUMBERS

DRKS00021764 and DRKS00021766.

Surgeon Postoperative Opioid Prescribing Intensity and Risk of Persistent Opioid Use Among Opioid-naive Adult Patients: A Population-based Cohort Study

OBJECTIVE

The aim of this study was to determine the relationship between surgeon opioid prescribing intensity and subsequent persistent opioid use among patients undergoing surgery.

SUMMARY BACKGROUND DATA

The extent to which different postoperative prescribing practices lead to persistent opioid use among surgical patients is poorly understood.

METHODS

Retrospective population-based cohort study assessing opioid-naive adults who underwent 1 of 4 common surgeries. For each surgical procedure, the surgeons' opioid prescribing intensity was categorized into quartiles based on the median daily dose of morphine equivalents of opioids dispensed within 7 days of the surgical visit for all the surgeons' patients. The primary outcome was persistent opioid use in the year after surgery, defined as 180 days or more of opioids supplied within the year after the index date excluding prescriptions filled within 30 days of the index date. Secondary outcomes included a refill for an opioid within 30 days and emergency department visits and hospitalizations within 1 year.

RESULTS

Among 112,744 surgical patients, patients with surgeons in the highest intensity quartile (Q4) were more likely to fill an opioid prescription within 7 days after surgery compared with those in the lowest quartile (Q1) (83.3% Q4 vs 65.4% Q1). In the primary analysis, the incidence of persistent opioid use in the year after surgery was rare in both highest and lowest quartiles (0.3% Q4 vs 0.3% Q1), adjusted odds ratio (AOR) of 1.18, 95% CI 0.83-1.66). However, multiple analyses using stricter definitions of persistent use that included the requirement of a prescription filled within 7 days of discharge after surgery showed a significant association with surgeon quartile (up to an AOR 1.36, 95% CI 1.25, 1.47). Patients in Q4 were more likely to refill a prescription within 30 days (4.8% Q4 vs 4.0% Q1, AOR 1.14, 95% CI 1.04-1.24).

CONCLUSIONS

Surgeons' overall prescribing practices may contribute to persistent opioid use and represent a target for quality improvement. However, the association was highly sensitive to the definition of persistent use used.

Risk factors for postoperative pain after cystocele repair with mesh

INTRODUCTION AND HYPOTHESIS

Prolapse is a common condition seen in women and its therapeutical management consists first and foremost of surgery. Postoperative pain is one of the most common side effects seen after surgery. The objective of this study was to identify risk factors for postoperative pain after cystocele repair with mesh.

METHODS

This is a secondary analysis of the multicenter randomized trial PROSPERE, which compared cystocele repair with mesh according to the vaginal or laparoscopic approach. The presence of postoperative pain was assessed by a pain-specific self-reported questionnaire (Questionnaire de Baudelocque). The statistical analysis is based on the Wilcoxon, Chi-squared, and Fisher's tests.

RESULTS

The prevalence of postoperative pain (pain persisting more than 6 months) was 39% (80 out of 205, 95% CI 32.4-46.1), with 6.3% (13 out of 205) of chronic pain reports. Preoperative pain was the only statistically significant risk factor OR = 2.32 (p = 0,007; 95% CI 1.24-4.36).

CONCLUSIONS

Surgeons must be careful with preoperative painful prolapse and should inform their patient of the risk of developing postoperative chronic pain.

Pain Treatment and Cancer Patients: Are we Heeding Quality of Life?

The use of opioid analgesics remains the primary therapy for pain control in cancer patients. However, ample evidence persists showing that treatment is still inadequate. This cross-sectional study was carried out during one year in a Brazilian Cancer Hospital to evaluate the impact of opioid use on analgesia and patients' quality of life. The Pain Management Index (PMI), EORTC QLQ.C30 (Quality of Life of Cancer Patients), Karnofsky Performance Status (KPS), Douleur Neuropathique 4 (DN4), and Brief Pain Inventory-Short Form (BPI-SF) were used. A hundred patients with advanced solid tumors and using opioids were included, with 82% of them reporting daily pain with 58% having intense pain. Morphine with a mean dose of 49 Morphine Milligram Equivalent were used by 57% of them, and PMI was negative in 34% of the sample. Neuropathic pain was found in 72% of patients. The pain was related to all BPI variables. Despite the substantial negative impact of pain on QOL, no association was found between the clinical factors assessed and QOL itself. This gap can be related to the persistence of high levels of sub-treatment, depression, and neuropathic pain associated with the use of low doses of opiates and adjuvant medications in the sample.

Pelvic pain is a common prolapse symptom and improvement after ventral mesh rectopexy is more frequent than deterioration or de novo pain

AIM

The aim of this work was to assess the relationship between pelvic pain and rectal prolapse both before prolapse surgery and in the long term after ventral mesh rectopexy (VMR).

METHOD

Patients undergoing VMR between 2004 and 2017 were contacted. Outcomes including the severity of pelvic pain were recorded using a numeric rating scale.

RESULTS

Four hundred and seventy eight of the 749 patients (64%) were successfully contacted. Of these, 39% reported pre-existing pelvic pain prior to VMR (group A) and 61% were pain free (group B). The median follow-up time was 8.0 years (interquartile range 5.0-10.0 years). Symptoms of obstructed defaecation were significantly more common (p = 0.002) in group A (91/187, 49%) than in group B (101/291, 35%). In contrast, faecal incontinence was more common (p = 0.007) in group B (75/291, 26%) than in group A (29/187, 15%). In group A, 76% showed improvement in pelvic pain after VMR: 61% were pain free and 39% had partial improvement in their pre-existing pelvic pain. Patients with persistent pelvic pain were younger (p = 0.01) and more likely to have revisional surgery after VMR (p = 0.0003), but there was no relation to the indication for surgery (p = 0.59). In group B, 15% reported de novo pelvic pain after VMR, and this was more common in women under 50 years old (p = 0.001), when obstructed defaecation was the indication (p = 0.03), in mesh erosion (p = <0.05) and when associated with revisional surgery (p = 0.005).

CONCLUSION

Pelvic pain is common (39%) in patients undergoing prolapse surgery, and VMR improves this pain in most patients (76%). However, a significant number of patients fail to improve (12%), experience worsening of pain (12%) or develop de novo pelvic pain (15%).

Continued persistent facial pain despite several surgical interventions in the temporomandibular joint

This article describes a woman in her forties who spontaneously developed facial pain 19 years after double-jaw orthognathic surgery. The focus of her pain was the left side of the face, including the temporomandibular joint (TMJ). Conservative treatment was initiated, including several occlusal splints, in addition to injections with local anesthesia, botulinum toxin, and corticosteroids, with limited effects. Surgical treatments with arthroscopy and discectomy, and ultimately a TMJ prosthesis, improved the patient's joint function but did not reduce pain. The question is whether the degenerated joint was due to progression of the original disease process or to multiple surgical procedures.

Plant-derived natural products targeting ion channels for pain

Chronic pain affects approximately one-fifth of people worldwide and reduces quality of life and in some cases, working ability. Ion channels expressed along nociceptive pathways affect neuronal excitability and as a result modulate pain experience. Several ion channels have been identified and investigated as potential targets for new medicines for the treatment of a variety of human diseases, including chronic pain. Voltage-gated channels Na⁺ and Ca²⁺ channels, K⁺ channels, transient receptor potential channels (TRP), purinergic (P2X) channels and acid-sensing ion channels (ASICs) are some examples of ion channels exhibiting altered function or expression in different chronic pain states. Pharmacological approaches are being developed to mitigate dysregulation of these channels as potential treatment options. Since natural compounds of plant origin exert promising biological and pharmacological properties and are believed to possess less adverse effects compared to synthetic drugs, they have been widely studied as treatments for chronic pain for their ability to alter the functional activity of ion channels. A literature review was conducted using Medline, Google Scholar and PubMed, resulted in listing 79 natural compounds/extracts that are reported to interact with ion channels as part of their analgesic mechanism of action. Most in vitro studies utilized electrophysiological techniques to study the effect of natural compounds on ion channels using primary cultures of dorsal root ganglia (DRG) neurons. In vivo studies concentrated on different pain models and were conducted mainly in mice and rats. Proceeding into clinical trials will require further study to develop new, potent and specific ion channel modulators of plant origin.

Transcutaneous electrical acupoint stimulation to reduce opioid consumption in patients undergoing inguinal hernia repair: protocol for a randomized controlled trial

BACKGROUND

The purpose of this study is to evaluate the efficacy and safety of transcutaneous electrical acupoint stimulation (TEAS) in the postoperative treatment of patients undergoing inguinal hernia repair compared with sham and no treatment group.

METHODS

This study is a protocol for a three-armed, single-blinded, placebo-controlled randomized controlled trial. Ninety participants scheduled for inguinal hernia repair will be randomly assigned to the TEAS group (n = 30), sham group (n = 30), and control group (n = 30). The TEAS group will receive treatment using four portable coin-sized electro-stimulators at both local and distal acupuncture points. The sham group will receive sham treatment with mock electrostimulation. The treatment groups will receive mixed frequency stimulation (alternating at 2 and 100 Hz every 3 s) in continuous mode for 30 min at intervals of 2 h for 24 h postoperatively. The control group will receive postoperative pain control using patient-controlled analgesia (PCA) device. The primary outcome is the total morphine dose received in the postoperative period (mg) using PCA 24 h after surgery. The number of PCA demands (i.e., times the button will be pressed) and delivered bolus doses, score on the Visual Analogue Scale, opioid-related side effects, the requirement for supplemental medications, score on the Hospital Anxiety and Depression Scale (HADS), and blood levels of stress hormones cortisol and prolactin.

DISCUSSION

The results of this trial will determine whether TEAS with intensified stimulation protocol is a safe and effective option for reducing analgesic consumption and postoperative pain.

TRIAL REGISTRATION

ISRCTN76428396. Registered on 05 October 2020. https://www.isrctn.com/ISRCTN76428396.

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

ABSTRACT

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

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

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

Sex-related differences in experimental pain sensitivity in subjects with painful or painless neuropathy after surgical repair of traumatic nerve injuries

Higher pain intensities at all experimental stimuli but a tendency to faster recovery after cold conditioning stimuli were seen in women with neuropathy in comparison with men.

Introduction:

Sex-related influences represent a contributor to greater pain sensitivity and have a higher prevalence of many chronic pain conditions, including neuropathic pain (NP), among women.

Objectives:

The aim was to analyze how differences in ongoing pain, experimental pain intensity, and conditioned pain modulation (CPM) relate to sex in subjects with neuropathy after traumatic nerve injuries.

Methods:

Endogenous pain modulation was compared between male (n = 77) and female (n = 55) subjects and between subjects with NP (female = 31, male = 39) and pain-free subjects with posttraumatic neuropathy (female = 24, male = 38). Conditioned pain modulation was assessed by pain ratings to pressure stimuli before and after a noxious conditioning stimulus (CS) conducted with one arm submerged in cold water (4°C) for 1 minute. Time of recovery (Time off) of pain intensity from peak VAS_maxc after CS was recorded and compared between male and female patients.

Results:

Greater ongoing pain intensity was found among female patients compared with male patients and more experimental pain after pressure and cold induced pain. Summing all groups together, women had 0.8 times higher odds (20%) of recovering sooner than men after CS (95% CI = 0.65–2.9). No differences in CPM, time off, and psychosocial variables were seen between female and male patients (P < 0.05).

Conclusion:

Our hypothesis for sex differences in endogenous pain modulation was only supported by a shorter after-sensation time after cold CS in female patients. No sex differences in the magnitude of CPM effect were identified. Increased pain intensity for experimental pain, in both neuropathic pain and neuropathy without pain, was found in female patients.

Monoaminergic mediation of hyperalgesic and analgesic descending control of nociception in mice

ABSTRACT

Descending control of nociception (DCN; also known as conditioned pain modulation [CPM], the behavioral correlate of diffuse noxious inhibitory controls) is the phenomenon whereby pain inhibits pain in another part of the body and is the subject of increasing study because it may represent a biomarker of chronic pain. We recently discovered that pain modulation upon application of a DCN paradigm involving low-intensity test stimuli occurs in the direction of hyperalgesia in healthy mice and rats, whereas the use of high-intensity stimuli produces analgesia. To elucidate the physiological mechanisms underlying hyperalgesic DCN, we administered agonists and antagonists of norepinephrine (NE) and serotonin (5-HT) receptors, key neurochemical players in the production of analgesic DCN. We find that three different monoamine reuptake inhibitors-the NE-selective reboxetine, the 5-HT-selective fluoxetine, and the dual NE/5-HT agonist duloxetine-all abolish hyperalgesic DCN when administered into the spinal cord (but not systemically), with no effect on heat or mechanical pain sensitivity. Reboxetine's attenuation of hyperalgesic DCN is mediated by α 2 -adrenergic receptors (i.e., blocked by atipamezole), and fluoxetine's effect is mediated by 5-HT 7 receptors (i.e., blocked by SB269970). In contrast, analgesic DCN was found to be reversed by atipamezole and SB269970 themselves, with no effect of reboxetine or fluoxetine. Thus, hyperalgesic DCN appears to be the neurochemical opposite to analgesic DCN. These data further validate and help elucidate a pre-clinical paradigm that mimics dysfunctional CPM, and thus may form the basis of translational experiments that aim to reveal preventative pharmacological strategies for individuals predisposed to persistent pain.

Sleep disturbance, dyspnea, and anxiety following total joint arthroplasty: an observational study

BACKGROUND

Patient-Reported Outcomes Measurement Information System (PROMIS) domains for sleep disturbance, anxiety, and dyspnea have been under-reported for total joint arthroplasty (TJA). The aims of this study were to report postoperative differences for these domains based on TJA location and chronic pain state. We also investigated whether these domains were associated with physical function and pain interference outcomes.

METHODS

This was a retrospective, observational study of patients who underwent hip, knee, or shoulder TJA (primary and revision surgeries) at a single academic tertiary referral center. A subset of these patients completed an email-based survey for chronic pain grade (Chronic Pain Grade Scale-Revised) and sleep disturbance, anxiety, dyspnea, physical function, and pain interference (PROMIS short forms). Pre-operative and operative data were extracted from the electronic health record. Data analysis investigated PROMIS domains for differences in TJA location and chronic pain grade. Hierarchical linear regression determined associations of these domains with physical function and pain interference.

RESULTS

A total of 2638 individuals provided informed consent and completed the email survey. In the ANOVA models for sleep disturbance, anxiety, and dyspnea, there was no location by chronic pain grade interaction (p > 0.05) and no difference based on TJA location (p > 0.05). There were differences for chronic pain grade (p < 0.01). The poorest postoperative outcome score for each domain was associated with high impact chronic pain. Furthermore, sleep disturbance and dyspnea had the strongest associations with physical function and pain interference (p < 0.01).

CONCLUSIONS

Sleep disturbance, anxiety, and dyspnea did not vary based on TJA location, but were associated with postoperative chronic pain grade. Sleep disturbance and dyspnea were strongly associated with commonly reported outcomes of physical function and pain interference. These findings provide guidance for those interested in expanding TJA outcome assessment to include sleep disturbance, anxiety, and/or dyspnea.

Kinematic Analyses Using Finger-Tapping Task for Patients After Surgery With Distal Radius Fracture at Acute Phase

BACKGROUND

After a distal radius fracture (DRF), severe pain, disabilities, and pain-related psychological problems can arise and sometimes remain ~1 year later. DRF-related disabilities have been assessed with questionnaires but not by kinematic evaluations; the kinematic features of DRF patients are unknown. Here, we investigated the kinematic characteristics of DRF patients and explored the relationship between their clinical assessments and kinematic characteristics.

METHODS

We analyzed 20 patients with DRFs after their surgeries. We recorded their finger-tapping using a magnetic sensor, and we calculated the velocity, magnitude, and movement-initiation hesitation. The patients' pain intensity and fear of movement were assessed by a visual analogue scale and the Disabilities of the Arm, Shoulder, and Hand Questionnaire (DASH). To investigate the features of the patients who achieved only slight improvement, we compared the kinematic characteristics of the DRF patients in 2 subgroups: the "good improvement group" and the "slight improvement group" based on a cutoff value of the DASH score (>40) at 1 month postsurgery.

RESULTS

The DASH score at 30 days postsurgery was significantly correlated with hesitation at 1 day postsurgery (r = .66, P < .0071) and with velocity at 7 days (r = -.54, P < .0071). Our kinematic analyses revealed significant differences in velocity at 7 days postsurgery (P < .05) and in hesitation at 1 day postsurgery (P < .05) between the subgroups.

CONCLUSIONS

Since assessments using range-of-motion measurements or a questionnaire are not sufficient to evaluate a patient's movement disorder, a kinematic analysis should be conducted for quantitative assessments.

Chronic postsurgical pain after minimally invasive adrenalectomy: prevalence and impact on quality of life

BACKGROUND

Minimally invasive adrenalectomy is the standard of care for small adrenal tumours. Both the transperitoneal lateral approach and posterior retroperitoneal approach are widely used and have been proven to be safe and effective. However, the prevalence of chronic postsurgical pain has not been specifically investigated in previous studies. The primary goal of this study was to identify the prevalence of chronic postsurgical pain after minimally invasive adrenalectomy.

METHODS

A cross-sectional study was performed among all consecutive patients who had undergone minimally invasive adrenalectomy in a single university medical centre. The primary outcome was the prevalence of chronic postsurgical pain. Secondary outcomes were the prevalence of localized hypoesthesia, risk factors for the development of chronic postsurgical pain, and the Health-Related Quality of Life. Three questionnaires were used to measure the prevalence and severity of chronic postsurgical pain, hypoesthesia, and Health-Related Quality of Life. Logistic regression analysis was performed to determine risk factors for development of chronic postsurgical pain.

RESULTS

Six hundred two patients underwent minimally invasive adrenalectomy between January 2007 and September 2019, of whom 328 signed informed consent. The prevalence of chronic postsurgical pain was 14.9%. In the group of patients with chronic postsurgical pain, 33% reported hypoesthesia as well. Young age was a significant predictor for developing chronic postsurgical pain. The prevalence of localized hypoesthesia was 15.2%. In patients with chronic postsurgical pain, Health-Related Quality of Life was significantly lower, compared to patients without pain.

CONCLUSIONS

The prevalence of chronic postsurgical pain following minimally invasive adrenalectomy is considerable. Furthermore, the presence of chronic postsurgical pain was correlated with a significant and clinically relevant lower Health-Related Quality of Life. These findings should be included in the preoperative counselling of the patient. In the absence of evidence for effective treatment in established chronic pain, prevention should be the key strategy and topic of future research.

Pain management with transdermal drug administration: A review

Pain management is an urgent issue to solve with complex mechanisms. Localized acute pain requires rapid and accurate delivery of drugs with less distribution in the blood circulation while chronic pain requires controlled release of drugs with long drug retention time. The transdermal route, a promising way with high patient compliance was known for painless delivery, long drug retention time, stable blood concentration, easily controlled dosage and release rate as well as the fewer side effects. This review presents transdermal route for pain management according to the different sites of action which drugs aim to reach, and illustrates different analgesic mechanisms, dosage forms, transdermal enhancements and clinical applications. In addition, the review concludes the difference of pain types and presents the future aims of pain management, thereby providing a reference for researches focusing on percutaneous analgesia.

Presence and predictors of pain after orthopedic surgery and associated orthopedic outcomes in children with cerebral palsy

While children with cerebral palsy (CP) may undergo 8‐22 orthopedic surgeries in their lifetime, little is known about the associated pain. We aimed to assess the pain presence before and one year after lower extremity orthopedic surgery, predictors of pain presence at follow‐up, and the association between pain and orthopedic outcomes related to surgery. This retrospective study included 86 children with CP (M age = 10.0 years, SD = 3.2; range = 4.1‐17.3 years, Gross Motor Functional Classification System (GMFCS) level I‐III) who underwent orthopedic surgery and had completed questionnaires at gait analyses before (M = 2.7 months; range = 0.0‐5.7) and after surgery (M = 11.8 months; range = 9.0‐14.9). Pain presence, location, and Pediatric Outcomes Data Collection Instrument (PODCI) scores were documented before and after surgery at gait analyses. Pain prevalence was 60% at baseline and 56% at follow‐up. Significant predictors of pain presence at follow‐up included (1) pain presence at baseline (range of odds ratios [OR] across any/all locations = 3.22 to 15.54), (2) older age (range of OR for any pain, back, knee, and foot pain = 1.24‐1.26), (3) female sex (decreased OR for males for ankle pain = 0.12), (4) having hip surgery (decreased OR for foot pain = 0.20), and (5) lower GMFCS level (OR for foot pain = 0.41). Changes in PODCI Sports and Physical Function scores were associated with changes in hip and knee pain (P < .03); PODCI scores worsened for patients who had pain at both time points and improved for patients who had pain at baseline but not follow‐up. Pain was present for over half of the participants before and after orthopedic surgery. Pain presence at follow‐up was predicted by pain presence at baseline. Pain and functional outcomes were correlated at follow‐up. Prospective studies examining perioperative pain experience and factors predicting pain outcomes are warranted.

Chronic Pain Prevalence and Factors Associated With High Impact Chronic Pain following Total Joint Arthroplasty: An Observational Study

Hip, knee, and shoulder arthroplasty are among the most frequently performed orthopaedic procedures in the United States. High impact and bothersome chronic pain rates following total joint arthroplasty (TJA) are unknown; as are factors that predict these chronic pain outcomes. This retrospective observational study included individuals that had a TJA from January 2014 to January 2020 (n = 2,638). Pre-operative and clinical encounter information was extracted from the electronic health record and chronic pain state was determined by email survey. Predictor variables included TJA location, number of surgeries, comorbidities, tobacco use, BMI, and pre-operative pain intensity. Primary outcomes were high impact and bothersome chronic pain. Rates of high impact pain (95% CI) were comparable for knee (9.8-13.3%), hip (8.3-11.8%) and shoulder (7.6-16.3%). Increased risk of high impact pain included non-white race, two or more comorbidities, age less than 65 years, pre-operative pain scores 5/10 or higher, knee arthroplasty, and post-operative survey completion 24 months or less. Rates of bothersome chronic pain (95% CI) were also comparable for knee (24.9-29.9%) and hip (21.3-26.3%) arthroplasty; but higher for shoulder (26.9-39.6%). Increased risk of bothersome chronic pain included non-white race, shoulder arthroplasty, knee arthroplasty, current or past tobacco use, and being female. PERSPECTIVE: In this cohort more than 1/3rd of individuals reported high impact or bothersome chronic pain following TJA. Non-white race and knee arthroplasty were the only two variables associated with both chronic pain outcomes.

New Vistas in microRNA Regulatory Interactome in Neuropathic Pain

Neuropathic pain is a chronic pain condition seen in patients with diabetic neuropathy, cancer chemotherapy-induced neuropathy, idiopathic neuropathy as well as other diseases affecting the nervous system. Only a small percentage of people with neuropathic pain benefit from current medications. The complexity of the disease, poor identification/lack of diagnostic and prognostic markers limit current strategies for the management of neuropathic pain. Multiple genes and pathways involved in human diseases can be regulated by microRNA (miRNA) which are small non-coding RNA. Several miRNAs are found to be dysregulated in neuropathic pain. These miRNAs regulate expression of various genes associated with neuroinflammation and pain, thus, regulating neuropathic pain. Some of these key players include adenylate cyclase (Ac9), toll-like receptor 8 (Tlr8), suppressor of cytokine signaling 3 (Socs3), signal transducer and activator of transcription 3 (Stat3) and RAS p21 protein activator 1 (Rasa1). With advancements in high-throughput technology and better computational power available for research in present-day pharmacology, biomarker discovery has entered a very exciting phase. We dissect the architecture of miRNA biological networks encompassing both human and rodent microRNAs involved in the development of neuropathic pain. We delineate various microRNAs, and their targets, that may likely serve as potential biomarkers for diagnosis, prognosis, and therapeutic intervention in neuropathic pain. miRNAs mediate their effects in neuropathic pain by signal transduction through IRAK/TRAF6, TLR4/NF-κB, TXIP/NLRP3 inflammasome, MAP Kinase, TGFβ and TLR5 signaling pathways. Taken together, the elucidation of the landscape of signature miRNA regulatory networks in neuropathic pain will facilitate the discovery of novel miRNA/target biomarkers for more effective management of neuropathic pain.

Virtual reality and hypnosis for anxiety and pain management in intensive care units: A prospective randomised trial among cardiac surgery patients

BACKGROUND

Virtual reality and hypnosis are little studied in complex contexts, such as intensive care, where patients need significant physical and psychological assistance.

OBJECTIVES

To compare and combine hypnosis and virtual reality benefits on anxiety and pain on patients before and after cardiac surgery.

DESIGN

Prospective randomised controlled clinical trial.

SETTING

The study was conducted in the University Hospital of Liege (Belgium) from October 2018 to January 2020.

PATIENTS

One hundred patients (66 ± 11.5 years; 24 women, 76 men) were included. Participants were adults undergoing cardiac surgery. Exclusion criteria: psychiatric diseases, claustrophobia, acrophobia, hearing loss, visual impairment, extreme fatigue, confusion surgery cancelled.

INTERVENTIONS

Patients were randomly assigned to four arms (control; hypnosis; virtual reality; virtual reality hypnosis) and had 20 min of one of the techniques the day before and the day after surgery.

MAIN OUTCOMES MEASURES

Anxiety, pain, fatigue, relaxation, physiological parameters, and opioid use were evaluated before and after each session.

RESULTS

The main results did not show any significant differences between the groups. In all groups, anxiety decreased and pain increased from baseline to the postoperative day. Relaxation increased in all groups in the pre-operative (P < 0.0001) and postoperative period (P = 0.03). There were no significant differences for fatigue, physiological measures, or opioid use.

CONCLUSION

As there were no significant differences between groups for the measured variables, we cannot affirm that one technique is better than another. Additional studies are required to compare and evaluate the cost-effectiveness of these techniques for critical care patients and caregivers.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT03820700. https://clinicaltrials.gov/ct2/show/NCT03820700. Retrospectively registered on 29 January 2019.

Chronic Pain Following Fracture-Related Surgery: Posttraumatic Rather Than Postsurgical Origin Promotes Chronification-A Prospective Observational Study With 1-Year Follow-up

BACKGROUND

Chronic posttraumatic/postsurgical pain (CPSP) is common after traumatic or surgical damage. Exposure to both trauma and surgery, with the potential for repeated bone and nerve damage, may increase the risk of CPSP after fracture-related surgery. But the (long-term) incidences of CPSP and neuropathic CPSP and the ensuing burdens are unknown. Therefore, the patients were prospectively assessed within 1 year, and the patient-specific characteristics were explored.

METHODS

Between 2017 and 2018, 127 patients (age: 52.9 ± 17.1 years, male: 55.1%) with traumatic fractures needing osteosynthesis (extremities: 91.3%) were assessed posttrauma (before surgery), postsurgery at days 1 to 5, 6 weeks, 3 and 12 months. The primary outcomes are as follows: incidence at 3 and 12 months of CPSP (defined as pain intensity on a numerical rating scale [NRS: 0-10] ≥3), secondary exploration: neuropathic CPSP (NRS ≥3 and Douleur Neuropathique 4 interview [DN4i] score ≥3 [Douleur Neuropathique interview: 0-7]); burden: quality of life (QoL, the EuroQOL five dimensions questionnaire [EQ-5D-3L] descriptive system); and inter alia, the number of analgesics (trial registration: DRKS00011601).

RESULTS

The incidence of CPSP was 57.1% (52/91, n/N) at 3 and 42.7% (35/82) at 12 months postsurgery, including neuropathic CPSP 7.7% (4/52) and 17.1% (6/35), respectively. Descriptively, posttraumatic higher pain intensity at rest (difference of 0.9 ± 1.8 NRS) and the need for more frequent analgesics (by 34.3%) were associated with CPSP a year after surgery compared to those without. As soon as week 6, these patients had developed descriptively a 15% more impaired QoL, with 25% more impairment after 1 year. The patients with CPSP presented with at least 1 neuropathic symptom 12 months later in 68.6% (24/35) of cases, mainly with an early posttraumatic occurrence (without fulfilling the definition of neuropathic CPSP).

CONCLUSIONS

After early fracture-related surgery, high incidences of CPSP (43%) were prospectively observed 1 year postsurgery, up to approximately 1 in 5 patients who had neuropathic CPSP. At the same time, CPSP was accompanied with an impacted QoL and analgesic dependence, both indicating clinical relevance. Moreover, the high incidence and the early posttraumatic occurrence of more intense pain suggest that the initial fracture-related trauma, rather than the surgical trauma, may predominantly trigger CPSP at Y1 (1 year). Therefore, these exploratory results set the direction of required future research. A future clinical hypothesis might be: treat first what hurts first.

Association of postoperative complications with persistent post-surgical pain: a multicentre prospective cohort study

BACKGROUND

Persistent post-surgical pain is an important and under-recognised problem that is difficult to treat. Postoperative complications have been identified as possible risk factors for persistent post-surgical pain. We conducted a secondary analysis of the Measurement of Exercise Tolerance before Surgery (METS) cohort study to characterise the association of major postoperative complications with post-surgical pain at 30 days and 1 yr after major surgery.

METHODS

The analysis included 1313 participants (≥40 yr old) who had inpatient noncardiac surgery and survived for 1 yr. The co-primary outcomes were 30-day post-surgical pain and 1-yr post-surgical pain. Post-surgical pain was defined as pain or discomfort that was of moderate or severe intensity (EuroQoL-5D [EQ-5D] instrument) and unimproved compared with preoperative pain or discomfort. The principal exposure was major in-hospital complications (moderate or severe by modified Clavien-Dindo criteria). Multivariable logistic regression modelling was used to characterise the adjusted association of major complications with outcomes.

RESULTS

Of the cohort, 12% (n=163) experienced major complications, 51% (n=674) reported 30-day post-surgical pain, and 42% (n=545) reported 1-yr post-surgical pain. Major complications were associated with 30-day post-surgical pain (adjusted odds ratio [aOR]=1.54; 95% confidence interval [CI], 1.05-2.23) and possibly 1-yr post-surgical pain (aOR=1.42; 95% CI, 0.98-2.06). When analyses were repeated after multiple imputation of missing covariate and outcome data, complications were associated with both 30-day and 1-yr post-surgical pain.

CONCLUSIONS

Patients who developed major complications were more likely to report pain at 30 days and possibly 1 yr after surgery. Research is necessary to validate these findings and delineate underlying mechanisms.

Predictors of Chronic Postsurgical Pain in Elderly Patients Undergoing Hip Arthroplasty: A Multi-Center Retrospective Cohort Study

Background

Identifying patients at high risk of developing chronic postsurgical pain (CPSP) is of extreme importance in order to help launch appropriate therapeutic strategies and intensive initiation of pain management.

Aim

In this study, we aimed to conduct a multi-center retrospective cohort study to establish a prognostic model and a nomogram to predict the risks of CPSP in elderly patients who underwent hip arthroplasty at 6 months postoperatively.

Methods

We collected data from 736 patients aged >65 years who had undergone hip arthroplasty from October 1, 2016 to September, 30, 2018 at multiple tertiary referral centers in Guangzhou, China. All data were randomly stratified into a training set and a testing set at a ratio of 8:2. Data were analyzed via multiple logistic regression analysis with receiver operating characteristic (ROC) curves and areas under the curve. This model was further validated by estimating calibration and discrimination. A nomogram was ultimately developed.

Results

A total of 736 eligible patients were enrolled, 27.20% of whom developed CPSP within 6 months postoperatively. Preoperative pain in the surgical area (OR=2.456, 95% CI:1.814–3.327, P<0.001), preoperative depression state (OR=1.256, 95% CI:1.146–1.378, P<0.001), surgical type (OR=7.138, 95% CI:3.548–14.364, P<0.001), acute postoperative numerical rating scale score (OR=5.537, 95% CI:3.607–8.499, P<0.001) and analgesic type (patient-controlled epidural analgesia: OR=0.129, 95% CI:0.055–0.299, P<0.001; patient-controlled intravenous analgesia: OR=0.033, 95% CI:0.011–0.097, P<0.001) were identified as independent significant factors associated with CPSP. A prognostic model was established and further validated. An ROC curve confirmed the predictive ability of this model with a high sensitivity value of 92.12% (95% CI:86.90–95.74) and specificity value of 91.72% (95% CI:88.77–94.11). A nomogram was developed to simplify the use of the predictive model in clinical practice.

Conclusion

This prognostic model could be of great value in clinical practice, serving as the basis for early personalized analgesic management of elderly patients undergoing hip arthroplasty.

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

Purpose

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

Patients and Methods

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

Results

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

Conclusion

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

Pain in the Cancer Survivor

Recent decades have demonstrated significant strides in cancer screening, diagnostics and therapeutics. As such there have been dramatic changes in survival following a diagnosis of cancer.

Psychophysical predictors of experimental muscle pain intensity following fatiguing calf exercise

Musculoskeletal pain affects approximately 20% of the population worldwide and represents one of the leading causes of global disability. As yet, precise mechanisms underlying the development of musculoskeletal pain and transition to chronicity remain unclear, though individual factors such as sleep quality, physical activity, affective state, pain catastrophizing and psychophysical pain sensitivity have all been suggested to be involved. This study aimed to investigate whether factors at baseline could predict musculoskeletal pain intensity to an experimental delayed onset of muscle soreness (DOMS) pain model. Demographics, physical activity, pain catastrophizing, affective state, sleep quality, isometric force production, temporal summation of pain, and psychophysical pain sensitivity using handheld and cuff algometry were assessed at baseline (Day-0) and two days after (Day-2) in 28 healthy participants. DOMS was induced on Day-0 by completing eccentric calf raises on the non-dominant leg to fatigue. On Day-2, participants rated pain on muscle contraction (visual analogue scale, VAS, 0-10cm) and function (Likert scale, 0–6). DOMS resulted in non-dominant calf pain at Day-2 (3.0±2.3cm), with significantly reduced isometric force production (P<0.043) and handheld pressure pain thresholds (P<0.010) at Day-2 compared to Day-0. Linear regression models using backward selection predicted from 39.3% (P<0.003) of VAS to 57.7% (P<0.001) of Likert score variation in DOMS pain intensity and consistently included cuff pressure pain tolerance threshold (P<0.01), temporal summation of pain (P<0.04), and age (P<0.02) as independent predictive factors. The findings indicate that age, psychological and central pain mechanistic factors are consistently associated with pain following acute muscle injury.

Sources of Individual Differences in Pain

Pain is an immense clinical and societal challenge, and the key to understanding and treating it is variability. Robust interindividual differences are consistently observed in pain sensitivity, susceptibility to developing painful disorders, and response to analgesic manipulations. This review examines the causes of this variability, including both organismic and environmental sources. Chronic pain development is a textbook example of a gene-environment interaction, requiring both chance initiating events (e.g., trauma, infection) and more immutable risk factors. The focus is on genetic factors, since twin studies have determined that a plurality of the variance likely derives from inherited genetic variants, but sex, age, ethnicity, personality variables, and environmental factors are also considered.

The effect of common variants in GDF5 gene on the susceptibility to chronic postsurgical pain

Background

The growth differentiation factor 5 (GDF5) gene regulates the growth of neuronal axons and dendrites and plays a role in the inflammatory response and tissue damage. The gene may also be associated with chronic postsurgical pain. This study aimed to reveal the relationship between SNPs in the GDF5 gene and orthopedic chronic postsurgical pain in Han Chinese population based on a case-control study.

Methods

We genotyped 8 SNPs within GDF5 gene in 1048 surgical patients with chronic postsurgical pain as the case group and 2062 surgical patients who were pain free as the control group. SNP and haplotypic analyses were performed, and stratified analyses were conducted to determine the correlations between significant SNPs and clinical characteristics.

Results

Only rs143384 in the 5′UTR of GDF5 was identified as significantly associated with increased susceptibility to chronic postsurgical pain, and the risk of A allele carriers was increased approximately 1.35-fold compared with that of G allele carriers. Haplotypes AGG and GGG in the LD block rs143384-rs224335-rs739329 also showed similar association patterns. Furthermore, we found that rs143384 was significantly correlated with chronic postsurgical pain in the subgroup aged ≤ 61 years, subgroup with a BMI ≤ 26, subgroup with no-smoking or no pain history, and subgroup with a drinking history.

Conclusion

Our study provided supportive evidence that genetic variations in the GDF5 gene are potential genetic factors that can increase the risk of chronic postsurgical pain in the Han Chinese population, but further research is necessary to elucidate the underlying mechanism.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02549-5.

Prevalence and predictors of chronic postsurgical pain after colorectal surgery: A prospective study

AIM

The aim was to investigate the incidence, characteristics and the potential predictors of chronic postsurgical pain (CPSP) after colorectal surgery.

METHOD

Patients who underwent colorectal surgery at our institution from July 2014 to December 2016 were prospectively enrolled in this study. Perioperative potential demographic, clinical and psychological predictors for CPSP were collected. The follow-up visits were conducted through telephone interviews at 3 and 6 months postoperatively. The interview questionnaire comprised items regarding pain intensity, frequency, site, analgesic administration and impact on activities of daily living.

RESULTS

A total of 624 patients completed the 6-month follow-up and were included in the analysis. CPSP was reported by 32.1% of these patients at 3 months and 21.8% at 6 months after colorectal surgery. The pain interfered with several activities of daily living in a considerable proportion of CPSP cases. At 3 months, the identified predictors of CPSP were young age, preoperative abdominal pain and pain elsewhere, preoperative anxiety and depression, longer duration of surgery, and high pain intensity on movement within 24 h after surgery. Predictors of CPSP at 6 months were young age, preoperative abdominal pain, preoperative anxiety, longer duration of surgery, and high pain intensity on movement within 24 h after surgery.

CONCLUSION

Chronic pain after colorectal surgery is a common complication associated with young age, preoperative abdominal pain and pain elsewhere, preoperative anxiety and depression, longer duration of surgery, and high pain intensity on movement within 24 h after surgery.

Enrollment in Treatment at a Specialized Pain Management Clinic at a Tertiary Referral Center after Surgery for Ulnar Nerve Compression: Patient Characteristics and Outcome

Purpose

To study patients who enroll in treatment at a specialized pain management clinic at a tertiary referral center following ulnar nerve decompression.

Methods

Data from medical charts and postoperative questionnaires were collected for all patients after surgery for ulnar nerve compression at the elbow from 2011 to 2014 (n = 173) at a tertiary referral center. Differences in characteristics between patients who enrolled in treatment at the pain management clinic (study group, n = 26) and the rest of the patients (reference group, n = 147) were analyzed. The study group was further evaluated using questionnaires from the Swedish Quality Registry for Pain Rehabilitation (SQRP) and regarding outcome of pain treatment.

Results

The study group was characterized by prior pain conditions, earlier contact with a pain management clinic, and high degrees of kinesiophobia, depression/anxiety, low quality of life, and low life satisfaction. These patients had significantly higher postoperative Disabilities of the Arm, Shoulder, and Hand (DASH) scores, were significantly younger, and had bilateral surgery significantly more often than the reference group. For patients with unilateral surgery, simple decompression was significantly more common in the reference group. The most common treatments at the clinic were antidepressants and anticonvulsants for neurogenic pain. In 5 of 26 patients, pain relief, or pain reduction was the documented reason for discharge.

Conclusions

Pain is a relevant outcome measure for ulnar nerve decompression among complicated cases at a referral center. Severe postoperative pain is connected to higher disability, reduced life satisfaction, and overall low health status. This study maps out characteristics of patients who postoperatively enroll in treatment at a specialized pain management clinic following ulnar nerve decompression. Further studies are needed to define predictive factors for such pain.

Type of study/level of evidence

Prognostic III.