Incidence of Chronic Postsurgical Pain (CPSP) after General Surgery

Bridging the pain gap after cancer surgery - Evaluating the feasibility of transitional pain service to prevent persistent postsurgical pain - A systematic review and meta-analysis

Background and Aims

The lack of a dedicated pain service catering to the postsurgical period has resulted in the origination of the pain-period gap. This has led to a resurgence of transitional pain service (TPS). Our objective was to evaluate the feasibility of TPS in pain practice among postsurgical cancer patients and its prevention of persistent postsurgical pain (PPSP), culminating in chronic pain catastrophising.

Methods

The protocol for this meta-analysis was registered in the International Prospective Register of Systematic Reviews (ID: CRD42023407190). This systematic review included articles involving all adult cancer patients undergoing cancer-related surgery experiencing pain, involving pharmacological, non-pharmacological and interventional pain modalities after an initial systematic pain assessment by pain care providers across diverse clinical specialities, targeting multimodal integrative pain management. Meta-analysis with meta-regression was conducted to analyse the feasibility of TPS with individual subgroup analysis and its relation to pain-related patient outcomes.

Results

Three hundred seventy-four articles were evaluated, of which 14 manuscripts were included in the meta-analysis. The lack of randomised controlled trials evaluating the efficacy of TPS in preventing PPSP and pain catastrophising led to the analysis of its feasibility by meta-regression. The estimate among study variances τ2 was determined and carried out along with multivariate subgroup analysis. A regression coefficient was attained to establish the correlation between the feasibility of TPS and its patient outcome measures and opioid-sparing.

Conclusion

TPS interventions carried out by multidisciplinary teams incorporating bio-physical-psychological pain interventions have resulted in its successful implementation with improved pain-related patient outcomes mitigating the occurrence of PPSP.

Prevalence of neuropathic pain in patients with symptomatic endometriosis: Assessment using the DN4 score

The mechanisms underlying pain in cases of endometriosis or chronic pelvic pain are complex, often involving various types of pain; mainly nociceptive pain, central sensitization, and neuropathic pain. Our main objective was to examine the prevalence of neuropathic pain in women with symptomatic endometriosis, and secondary, to explore the factors associated with this type of pain and to assess the prevalence of a positive PPSC score and a history of sexual violence within this population. This study is a retrospective, comparative, single-center cohort study conducted from September 2019 to January 2023. The presence of neuropathic pain was confirmed by a positive DN4 score, defined as greater than or equal to 4. The association with the following variables was studied: age, BMI, marital status, smoking, alcohol and drugs consumption, age at menarche, gestity, parity, duration of exposure to endometriosis, MRI locations, laparoscopy for endometriosis and post-laparoscopy r-ASRM classification, hormone treatment, associated symptoms, VAS, associated pathologies, infertility consultation, Pain Center consultation, EPH-5 score, positive PPSC score (≥5), and history of sexual violence. The prevalence of neuropathic pain was 44.1%. Younger age, being in a relationship, having a high EPH-5 score and undergoing laparoscopy for endometriosis are associated with neuropathic pain independently of other variables. Our study underscores the persistent high prevalence of neuropathic pain in endometriosis cases, emphasizing the importance of actively screening for it. Identifying neuropathic pain could prompt referrals to pain specialists, integrating it into a comprehensive multidisciplinary approach.

Vagus nerve stimulation rescues persistent pain following orthopedic surgery in adult mice

ABSTRACT

Postoperative pain is a major clinical problem imposing a significant burden on patients and society. In a survey 2 years after orthopedic surgery, 57% of patients reported persisting postoperative pain. However, only limited progress has been made in the development of safe and effective therapies to prevent the onset and chronification of pain after orthopedic surgery. We established a tibial fracture mouse model that recapitulates clinically relevant orthopedic trauma surgery, which causes changes in neuropeptide levels in dorsal root ganglia and sustained neuroinflammation in the spinal cord. Here, we monitored extended pain behavior in this model, observing chronic bilateral hindpaw mechanical allodynia in both male and female C57BL/6J mice that persisted for >3 months after surgery. We also tested the analgesic effects of a novel, minimally invasive, bioelectronic approach to percutaneously stimulate the vagus nerve (termed percutaneous vagus nerve stimulation [pVNS]). Weekly pVNS treatment for 30 minutes at 10 Hz for 3 weeks after the surgery strongly reduced pain behaviors compared with untreated controls. Percutaneous vagus nerve stimulation also improved locomotor coordination and accelerated bone healing. In the dorsal root ganglia, vagal stimulation inhibited the activation of glial fibrillary acidic protein-positive satellite cells but without affecting microglial activation. Overall, these data provide novel evidence supportive of the use of pVNS to prevent postoperative pain and inform translational studies to test antinociceptive effects of bioelectronic medicine in the clinic.

Incidence and predictors of chronic pain after inguinal hernia surgery: a systematic review and meta-analysis

PURPOSE

The mesh is currently the preferred treatment option for hernia repair surgery. Chronic postoperative inguinal pain (CPIP), lasting more than 3 months after surgery, is a complication that significantly impacts patients' quality of life. Currently, there is a lack of evidence-based information describing the incidence and independent predictive factors of chronic pain, posing a serious challenge in clinical practice for devising personalized prevention strategies. Hence, we conducted this systematic review and meta-analysis to investigate the incidence and predictive factors, aiming to provide a reference for developing plans to prevent chronic pain.

METHODS

We conducted a systematic search of PubMed, Cochrane, Embase, and Web of Science, with the retrieval cutoff date set at December 17, 2022. The included studies underwent assessment using the NOS scale, and subgroup analysis for the incidence was carried out based on different regions.

RESULTS

Ultimately, 18 studies were included, involving 29,466 patients. Meta-analysis showed that the pooled incidence of chronic pain was 17.01% (95%CI 12.78% ~ 21.71%). The incidence was 18.65% (95%CI 13.59% ~ 24.29%) in Europe, 14.70% (95%CI 7.87% ~ 23.17%) in Asia, and 6.04%(95%CI 4.62 ~ 7.64) in North America. Furthermore, We also found that the risk factors for CPIP are younger age [OR = 2.261 (95%CI 1.126 ~ 4.549)], presence of other postoperative complications [OR = 1.849 (95%CI 1.034 ~ 3.305)], hernial sac defect < 3 cm [OR = 1.370 (95%CI 1.012 ~ 1.853)], being female [OR = 1.885 (95%CI 1.024 ~ 3.472)], postoperative pain [OR = 1.553 (95%CI 1.276 ~ 1.889)], preoperative pain [OR = 2.321 (95%CI 1.354 ~ 3.979)], and having a history of ipsilateral inguinal hernia repair [OR = 2.706 (95% CI 1.445 ~ 5.069)].

CONCLUSIONS

The incidence of persistent pain following hernia repair surgery is high in current clinical practice, a concern that should not be overlooked. Stratified assessment tools need to be established for patients experiencing early chronic pain, and personalized follow-up strategies and preventive interventions should be developed for those with potentially high risks. These measures aim to enhance the quality of life for patients after hernia repair.

CXCL13/CXCR5 promote chronic postsurgical pain and astrocyte activation in rats by targeting NLRP3

Chronic postsurgical pain (CPSP) with high incidence negatively impacts the quality of life. X-C motif chemokine 13 (CXCL13) has been associated with postsurgery inflammation and exacerbates neuropathic pain in patients with CPSP. This study was aimed to illustrate the relationship between CXCL13 and nod-like receptor protein-3 (NLRP3), which is also involved in CPSP. A CPSP model was constructed by skin/muscle incision and retraction (SMIR) in right medial thigh, and the rats were divided into three groups: Sham, SMIR, and SMIR + anti-CXCL13 (intrathecally injected with anti-CXCL13 antibody). Then, the paw withdrawal threshold (PWT) score of rats was recorded. Primary rat astrocytes were isolated and treated with recombinant protein CXCL13 with or without NLRP3 inhibitor INF39. The expressions of CXCL13, CXCR5, IL-1β, IL-18, GFAP, NLRP3, and Caspase-1 p20 were detected by real-time quantitative reverse transcription PCR, western blot, ELISA, immunocytochemistry, and immunofluorescence analyses. The anti-CXCL13 antibody alleviated SMIR-induced decreased PWT and increased expression of GFAP, CXCL13, CXCR5, NLRP3, and Caspase-1 p20 in spinal cord tissues. The production of IL-1β, IL-18, and expression of CXCL13, CXCR5, GFAP, NLRP3, and Caspase-1 p20 were increased in recombinant protein CXCL13-treated primary rat astrocytes in a dose-dependent manner. Treatment with NLRP3 inhibitor INF39 inhibited the function of recombinant protein CXCL13 in primary rat astrocytes. The CXCL13/CXCR5 signaling could promote neuropathic pain, astrocytes activation, and NLRP3 inflammasome activation in CPSP model rats by targeting NLRP3. NLRP3 may be a potential target for the management of CPSP.

Incidence of persistent opioid use following traumatic injury

INTRODUCTION

Major traumatic injuries are a known risk factor for persistent opioid use, but data describing the relationship between specific traumatic injuries and opioid use is lacking.

METHODS

We used insurance claims data from January 1, 2001 to December 31, 2020 to estimate the incidence of new persistent opioid use in three hospitalized trauma populations: individuals hospitalized after burn injury (3809, 1504 of whom required tissue grafting), individuals hospitalized after motor vehicle collision (MVC; 9041), and individuals hospitalized after orthopedic injury (47, 637). New persistent opioid use was defined as receipt of ≥1 opioid prescriptions 90-180 days following injury in an individual with no opioid prescriptions during the year prior to injury.

RESULTS

New persistent opioid use was observed in 12% (267/2305) of individuals hospitalized after burn injury with no grafting, and 12% (176/1504) of burn injury patients requiring tissue grafting. In addition, new persistent opioid use was observed in 16% (1454/9041) of individuals hospitalized after MVC, and 20% (9455/47, 637) of individuals hospitalized after orthopedic trauma. In comparison, rates of persistent opioid use in all trauma cohorts (19%, 11, 352/60, 487) were greater than the rates of persistent opioid use in both non-traumatic major surgery (13%) and non-traumatic minor surgery (9%).

CONCLUSIONS

These data demonstrate that new persistent opioid use frequently occurs in these common hospitalized trauma populations. Improved interventions to reduce persistent pain and opioid use in patients hospitalized after these and other traumas are needed.

General practice management of chronic post-surgical pain in patients with hip fracture: a qualitative study

Background

Hip fractures are common among elderly people and often lead to chronic post-surgical pain (CPSP). Effective CPSP management when patients transition from hospital to community settings is essential, but has not been sufficiently researched. This study examined general practitioner (GP) perspectives on managing patients with CPSP after hip fractures in Shanghai, China.

Methods

A descriptive qualitative study was performed wherein semi-structured interviews were conducted with GPs practicing in Shanghai who volunteered to participate. This study was initiated after a regional survey of general practice care for patients with CPSP following hip fracture.

Results

Six key themes emerged: (1) GPs' care priorities for patients with CPSP varied; (2) pharmacological management posed challenges in terms of selecting appropriate medications; (3) consultation time constraints hindered comprehensive management; (4) GPs desired better communication from hospitals at discharge; (5) limited access to services, such as pain specialists and allied health, obstructed optimal care delivery; and (6) patient nonadherence to CPSP treatment was an issue.

Conclusion

Multiple patient-, provider-, and system-level factors affected GP care for patients with CPSP after hip fracture. Improved interdisciplinary communication and education on evidence-based CPSP guidelines are needed to address the knowledge gaps among GPs. Barriers to healthcare access must be minimized to facilitate guideline-based care.

Artificial intelligent patient-controlled intravenous analgesia improves the outcomes of older patients with laparoscopic radical resection for colorectal cancer

METHODS

Patients undergoing elective laparoscopic radical resection of colorectal cancer from July 2019 to May 2021 were selected. The patients were assigned to Ai-PCIA group and control group. Ai-PCIA group received postoperative analgesia management and effect evaluation through intelligent wireless analgesia system + postoperative follow-up twice a day, while control group received analgesia management and effect evaluation through ward physician feedback + postoperative follow-up twice a day. The pain numerical score (NRS), Richards-Campbell Sleep Scale (RCSQ), and adverse outcomes were collected and compared.

RESULTS

A total of 60 patients (20 females and 40 males with average (78.26 ± 6.42) years old) were included. The NRS scores at rest and during activity of the Ai-PCA group at 8, 12, and 24 h after the operation were significantly lower than that of the control group (all P < 0.05). The RCSQ score of Ai-PCA group was significantly higher than that of control group on the 1st and 2nd days after operation (all P < 0.05). There were no significant differences in the incidence of dizziness and nausea, vomiting, and myocardial ischemia (all P > 0.05).

CONCLUSIONS

Ai-PCIA can improve the analgesic effect and sleep quality of older patients after laparoscopic radical resection, which may be promoted in clinical analgesia practice.

Comprehensive quantitative sensory testing shows altered sensory function in women with chronic pelvic pain: results from the Translational Research in Pelvic Pain (TRiPP) Study

ABSTRACT

Chronic pelvic pain (CPP), despite its high prevalence, is still relatively poorly understood mechanistically. This study, as part of the Translational Research in Pelvic Pain (TRiPP) project, has used a full quantitative sensory testing (QST) paradigm to profile n = 85 women with and without CPP (endometriosis or bladder pain specifically). We used the foot as a control site and abdomen as the test site. Across 5 diagnostically determined subgroups, we found features which are common across different aetiologies, eg, gain of function in pressure pain threshold (PPT) when assessing responses from the lower abdomen or pelvis (referred pain site). However, disease-specific phenotypes were also identified, eg, greater mechanical allodynia in endometriosis, despite there being large heterogeneities within diagnostic groups. The most common QST sensory phenotype was mechanical hyperalgesia (>50% across all the groups). A "healthy' sensory phenotype was seen in <7% of CPP participants. Specific QST measures correlated with sensory symptoms assessed by the painDETECT questionnaire (pressure-evoked pain [painDETECT] and PPT [QST] [ r = 0.47, P < 0.001]; mechanical hyperalgesia (painDETECT) and mechanical pain sensitivity [MPS from QST] [ r = 0.38, P = 0.009]). The data suggest that participants with CPP are sensitive to both deep tissue and cutaneous inputs, suggesting that central mechanisms may be important in this cohort. We also see phenotypes such as thermal hyperalgesia, which may be the result of peripheral mechanisms, such as irritable nociceptors. This highlights the importance of stratifying patients into clinically meaningful phenotypes, which may have implications for the development of better therapeutic strategies for CPP.

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.

Vagus nerve stimulation rescues persistent pain following orthopedic surgery in adult mice

Postoperative pain is a major clinical problem imposing a significant burden on our patients and society. Up to 57% of patients experience persistent postoperative pain 2 years after orthopedic surgery [49]. Although many studies have contributed to the neurobiological foundation of surgery-induced pain sensitization, we still lack safe and effective therapies to prevent the onset of persistent postoperative pain. We have established a clinically relevant orthopedic trauma model in mice that recapitulates common insults associated with surgery and ensuing complications. Using this model, we have started to characterize how induction of pain signaling contributes to neuropeptides changes in dorsal root ganglia (DRG) and sustained neuroinflammation in the spinal cord [62]. Here we have extended the characterization of pain behaviors for >3 months after surgery, describing a persistent deficit in mechanical allodynia in both male and female C57BL/6J mice after surgery. Notably, we have applied a novel minimally invasive bioelectronic approach to percutaneously stimulate the vagus nerve (termed pVNS) [24] and tested its anti-nociceptive effects in this model. Our results show that surgery induced a strong bilateral hind-paw allodynia with a slight decrease in motor coordination. However, treatment with pVNS for 30-minutes at10 Hz weekly for 3 weeks prevented pain behavior compared to naïve controls. pVNS also improved locomotor coordination and bone healing compared to surgery without treatment. In the DRGs, we observed that vagal stimulation fully rescued activation of GFAP positive satellite cells but did not affect microglial activation. Overall, these data provide novel evidence for the use of pVNS to prevent postoperative pain and may inform translational studies to test anti-nociceptive effects in the clinic.

A Lifelong Impact on Endometriosis: Pathophysiology and Pharmacological Treatment

Endometriosis is a chronic inflammatory disease associated with bothersome symptoms in premenopausal women and is complicated with long-term systemic impacts in the post-menopausal stage. It is generally defined by the presence of endometrial-like tissue outside the uterine cavity, which causes menstrual disorders, chronic pelvic pain, and infertility. Endometriotic lesions can also spread and grow in extra-pelvic sites; the chronic inflammatory status can cause systemic effects, including metabolic disorder, immune dysregulation, and cardiovascular diseases. The uncertain etiologies of endometriosis and their diverse presentations limit the treatment efficacy. High recurrence risk and intolerable side effects result in poor compliance. Current studies for endometriosis have paid attention to the advances in hormonal, neurological, and immunological approaches to the pathophysiology and their potential pharmacological intervention. Here we provide an overview of the lifelong impacts of endometriosis and summarize the updated consensus on therapeutic strategies.

Perioperative opioids: a narrative review contextualising new avenues to improve prescribing

Opioids have dominated the management of perioperative pain in recent decades with higher doses than ever before used in some circumstances. Through the expanding use of opioids, growing research has highlighted their associated side-effects and the intertwined phenomena of acute withdrawal syndrome, opioid tolerance, and opioid-induced hyperalgesia. With multiple clinical guidelines now endorsing multimodal analgesia, a diverse array of opioid-sparing agents emerges and has been studied to variable degrees, including techniques of opioid-free anaesthesia. It remains unclear to what extent such methods should be adopted, yet current evidence does suggest dependence on opioids as the primary perioperative analgesic might not meet the principles of 'rational prescribing' as described by Maxwell. In this narrative review we describe how, using current evidence, a patient-centred rational-prescribing approach can be applied to opioids in the perioperative period. To contextualise this approach, we discuss the historical adoption of opioids in anaesthesia, our growing understanding of associated side-effects and emerging strategies of opioid-sparing and opioid-free anaesthesia. We discuss avenues and challenges for improving opioid prescribing to limit persistent postoperative opioid use and how these may be incorporated into a rational-prescribing approach.

Trajectory of worst pain within the first two weeks following pelvic and sacral tumor surgery and long-term outcome: a pilot observational prospective cohort study

BACKGROUND

Pain management after pelvic and sacral tumor surgery is challenging and requires a multidisciplinary and multimodal approach. Few data on postoperative pain trajectories have been reported after pelvic and sacral tumor surgery. The aim of this pilot study was to determine pain trajectories within the first 2 weeks after surgery and explore the impact on long-term pain outcomes.

METHODS

Patients scheduled for pelvic and sacral tumor surgery were prospectively recruited. Worst/average pain scores were evaluated postoperatively using questions adapted from the Revised American Pain Society Patient Outcome Questionnaire (APS-POQ-R) until pain resolution was reached or up to 6 months after surgery. Pain trajectories over the first 2 weeks were compared using the k-means clustering algorithm. Whether pain trajectories were associated with long-term pain resolution and opioid cessation was assessed using Cox regression analysis.

RESULTS

A total of 59 patients were included. Two distinct groups of trajectories for worst and average pain scores over the first 2 weeks were generated. The median pain duration in the high vs low pain group was 120.0 (95% CI [25.0, 215.0]) days vs 60.0 (95% CI [38.6, 81.4]) days (log rank p = 0.037). The median time to opioid cessation in the high vs low pain group was 60.0 (95% CI [30.0, 90.0]) days vs 7.0 (95% CI [4.7, 9.3]) days (log rank p < 0.001). After adjusting for patient and surgical factors, the high pain group was independently associated with prolonged opioid cessation (hazard ratio [HR] 2.423, 95% CI [1.254, 4.681], p = 0.008) but not pain resolution (HR 1.557, 95% CI [0.748, 3.243], p = 0.237).

CONCLUSIONS

Postoperative pain is a significant problem among patients undergoing pelvic and sacral tumor surgery. High pain trajectories during the first 2 weeks after surgery were associated with delayed opioid cessation. Research is needed to explore interventions targeting pain trajectories and long-term pain outcomes.

TRIAL REGISTRATION

The trial was registered at ClinicalTrials.gov ( NCT03926858 , 25/04/2019).

Rodent Animal Models of Endometriosis-Associated Pain: Unmet Needs and Resources Available for Improving Translational Research in Endometriosis

Chronic pain induced by endometriosis is a maladaptive pain experienced by half of women with this disease. The lack of pharmacological treatments suitable for the long-term relief of endometriosis-associated pain, without an impact on fertility, remains an urgent unmet need. Progress has been slowed by the absence of a reproducible rodent endometriosis model that fully replicates human physiopathological characteristics, including pain symptoms. Although pain assessment in rodents is a complicated task requiring qualified researchers, the choice of the behavioral test is no less important, since selecting inappropriate tests can cause erroneous data. Pain is usually measured with reflex tests in which hypersensitivity is evaluated by applying a noxious stimulus, yet this ignores the associated emotional component that could be evaluated via non-reflex tests. We conducted a systematic review of endometriosis models used in rodents and the number of them that studied pain. The type of behavioral test used was also analyzed and classified according to reflex and non-reflex tests. Finally, we determined the most used reflex tests for the study of endometriosis-induced pain and the main non-reflex behavioral tests utilized in visceral pain that can be extrapolated to the study of endometriosis and complement traditional reflex tests.

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%).

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.

Considerations for Better Management of Postoperative Pain in Light of Chronic Postoperative Pain: A Narrative Review

Chronic postoperative pain (CPOP) is prevalent, with particularly high rates in breast surgery, thoracotomy, and amputation. As the world emerges from the coronavirus disease 2019 (COVID-19) lockdowns, it is expected that there will be an increase in surgical procedures, elevating the importance of preventing CPOP in the coming years. Risk factors are emerging to better stratify patients at high risk for CPOP. Perioperative analgesia plays an important role in managing acute postoperative pain and in some cases may limit its transition to CPOP. Acute postoperative pain is adaptive, normal, expected, and has a well-defined trajectory, while CPOP is maladaptive and, as a form of chronic pain, is challenging to treat. Good analgesia, early ambulation, and rehabilitation efforts may be helpful in preventing CPOP following certain surgeries. Enhanced Recovery After Surgery (ERAS) protocols present guidance to help promote recovery and prevent CPOP.

Is There a Neuropathic-Like Component to Endometriosis-Associated Pain? Results From a Large Cohort Questionnaire Study

Background: Pain is one of the primary symptoms of endometriosis, a chronic inflammatory condition characterised by the presence of endometrial tissue outside the uterus. Endometriosis-associated pain is commonly considered as nociceptive in nature, but its clinical presentation suggests that it might have neuropathic-like properties in a subgroup of patients.

Methods: This is a cross sectional study using an online survey. The survey was distributed by patient support websites. The survey was composed of validated questionnaires assessing pain symptoms, psychological measures and questions about number of surgeries.

Main Results: We had 1,417 responses which met the inclusion criteria. Using standard painDETECT cut-off scores, we found that pain was classified as neuropathic in 40% of patients and as mixed neuropathic/nociceptive in a further 35%. In line with observations in other neuropathic conditions, the neuropathic subgroup reported higher pain intensities, greater psychological distress and cognitive impairment. Neuropathic pain was also more likely in those with more surgeries to the abdomen and a longer history of pain. As revealed by a cluster analysis, those with a neuropathic pain component could further be divided into two subgroups based on their sensory profile.

Conclusions: The data presented here indicate that endometriosis-associated pain includes a neuropathic-like component in a substantial proportion of women. Although further investigation is required, our finding challenges the current conceptualisation of endometriosis-associated pain as nociceptive and advocates for a new perspective on this type of pain, which is so debilitating to a large number of women.

The Effect of Single-Shot Erector Spinae Plane Block (ESPB) on Opioid Consumption for Various Surgeries: A Meta-Analysis of Randomized Controlled Trials

Study Objective

Design

Setting

Patients

Intervention

Measurements

Results

Conclusion

Avoid Postoperative Pain To Prevent Its Chronification: A Narrative Review

Acute postoperative pain is a normal and expected part of the patient’s postsurgical trajectory, and its intensity, severity, and duration vary with surgery-related and patient factors. In a subset of patients, postoperative pain does not resolve as the tissue heals but instead transitions to chronic postoperative pain, a challenging condition to treat and one associated with decreased quality of life, sleep and mood disorders, and neuropathy. Promptly and adequately treating acute postoperative pain can reduce the risk that it will transition into chronic postoperative pain. Numerous agents are available that may help treat postoperative pain, including nonsteroidal anti-inflammatory drugs, opioids, antidepressants, anticonvulsants, and others. In this connection, it is also important to consider patient factors, such as mental health status and comorbidities, as well as the type and duration of surgery. A multimodal approach is recommended, which uses two or more agents with complementary mechanisms of action, working at different targets. Multimodal analgesia may also reduce adverse events and lessen opioid consumption after surgery. A particularly useful fixed-dose combination product is dexketoprofen/tramadol (DEX-TRA), which is safe and effective in numerous clinical trials. This review is based on a presentation from the Roma Pain Days scientific sessions of 2021.

Pain Management Strategies After Orthopaedic Trauma: A Mixed-Methods Study with a View to Optimizing Practices

PURPOSE

To examine 1) pain management strategies within the care trajectory of orthopaedic trauma patients and patients' perception of their effectiveness, 2) adverse effects (AEs) associated with pharmacological treatments, particularly opioids and cannabis, and 3) patients' perceptions of strategies that should be applied after an orthopaedic trauma and support that they should obtain from health professionals for their use.

PATIENTS AND METHODS

This study was conducted with orthopaedic trauma patients in a level 1 trauma center. A convergent mixed-methods design was used. Data on pain experience, pain management strategies used and AEs were collected with self-administered questionnaires at hospital discharge (T1) and at 3 months after injury (T2). Patients' preferences about the pain management strategies used, the required support and AEs were further examined through semi-structured individual interviews at the same time measures. Descriptive statistics and thematic analyses were performed.

RESULTS

Seventy-one patients were recruited and 30 individual interviews were undertaken. Pharmacological pain management strategies used at T1 and T2 were mainly opioids (95.8%; 20.8%) and acetaminophen (91.5%; 37.5%). The most frequently applied non-pharmacological strategies were sleep (95.6%) and physical positioning (89.7%) at T1 and massage (46.3%) and relaxation (32.5%) at T2. Findings from quantitative and qualitative analyses highlighted that non-pharmacological strategies, such as comfort, massage, distraction, and physical therapy, were perceived as the most effective by participants. Most common AEs related to opioids were dry mouth (78.8%) and fatigue (66.1%) at T1 and insomnia (30.0%) and fatigue (20.0%) at T2. Dry mouth (28.6%) and drowsiness (14.3%) were the most reported AEs by patients using recreational cannabis. An important need for information at hospital discharge and for a personalized follow-up was identified by participants during interviews.

CONCLUSION

Despite its AEs, we found that opioids are still the leading pain management strategy after an orthopaedic trauma and that more efforts are needed to implement non-pharmacological strategies. Cannabis was taken for recreational purposes but patients also used it for pain relief. Support from health professionals is needed to promote the adequate use of these strategies.

Capsaicin 179-mg cutaneous patch in the treatment of post-surgical neuropathic pain: a scoping review of current evidence and place in therapy

INTRODUCTION

The use of topical agents has been suggested for post-surgical neuropathic pain. A high-concentration capsaicin 179-mg cutaneous patch (Qutenza™) is licensed in adults for chronic neuropathic pain in the EU, and neuropathic pain with post-herpetic neuralgia and neuropathic pain with diabetic peripheral neuropathy in the USA. This article aims to describe the use of a topical capsaicin 179-mg cutaneous patch in the treatment of PSNP.

AREA COVERED

This narrative review presents the relevant clinical aspects of the use of a topical capsaicin 179-mg cutaneous patch for the treatment of post-surgical neuropathic pain (PSNP). Randomized control trials, observational studies, case series, and reports investigating the clinical use of the capsaicin patch were searched through MEDLINE, EMBASE, AMED, Cochrane Library, CINAHL, Web of Science, and ROAD databases. Trials from citation lists of reviewed articles and hand-searching were added. The search concluded in September 2020. 10/20 articles were considered.

EXPERT OPINION

Some clinical studies demonstrated the efficacy of the capsaicin 179-mg patch in PSNP as monotherapy and concomitant treatment with oral treatments. This topical treatment of PSNP is better tolerated and accepted compared with systemic treatments. To maximize the effectiveness of the treatment, correct administration recommendations should be followed.

Chinese Association for the Study of Pain: Expert consensus on chronic postsurgical pain

Chronic postsurgical pain is a common surgical complication that severely reduces a patient’s quality of life. Many perioperative interventions and management strategies have been developed for reducing and managing chronic postsurgical pain. Under the leadership of the Chinese Association for the Study of Pain, an editorial committee was formed for chronic postsurgical pain diagnosis and treatment by experts in relevant fields. The editorial committee composed the main content and framework of this consensus and established a working group. The working group conducted literature review (1989-2020) using key words such as “surgery”, “post-surgical”, “post-operative”, “pain”, “chronic”, and “persistent” in different databases including MEDLINE, EMBASE, PubMed, Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews. Only publications in the English language were included. The types of literature included systematic reviews, randomized controlled studies, cohort studies and case reports. This consensus was written based on clinical practice combined with literature evidence. The first draft of the consensus was rigorously reviewed and edited by all the editorial committee experts before being finalized. The level of evidence was assessed by methodological experts based on the Oxford Centre for Evidence-Based Medicine Levels of Evidence. The strength of recommendation was evaluated by all editorial committee experts, and the opinions of most experts were adopted as the final decision. The recommendation level “strong” generally refers to recommendations based on high-level evidence and consistency between clinical behavior and expected results. The recommendation level “weak” generally refers to the uncertainty between clinical behavior and expected results based on low-level evidence.

Pain in survivors of Ewing sarcoma: Prevalence, associated factors and prediction of recurrence

BACKGROUND

While the prognosis of patients with Ewing sarcoma (EwS) is improving, little is known about the frequency of pain and its risk factors in survivors of EwS. This study aims to analyse the prevalence and risk factors of pain and its predictive value for recurrence.

PATIENTS AND METHODS

In patients with remission after treatment of EwS, frequency and characteristics of pain within the first 5 years of follow up were assessed retrospectively.

RESULTS

Of 80 patients, 37 (46%) presented with at least one episode of pain. Chronic pain (>3 months) was observed in 10 patients (13%). Experience of at least one episode of pain was associated with prior combined local treatment (surgery and radiation compared to surgery alone; odds ratio [OR] 5.83, 95% confidence interval [CI] 1.43-34.9, P = .007). A total of 59 episodes of pain were observed, including 47 acute and 12 chronic episodes. Lower limb pain accounted for 46% (27/59) of all episodes of pain, and was associated with primary tumour of the pelvis or lower extremity (OR 4.29, 95% CI 1.18-18.21, P = .025), which represented 64% (51/80) of all EwS. The positive predictive value of pain for recurrence was only 12%.

CONCLUSION

Pain is a common problem in survivors of EwS, which mostly affects the lower extremity, and should be regularly assessed. Interventions to reduce pain may be particularly important in patients with combined local treatment with surgery and radiation, who seem to be at considerably increased risk for pain. Patients presenting with pain should be examined for recurrence.

Unwillingly traumatizing: is there a psycho-traumatologic pathway from general surgery to postoperative maladaptation?

BACKGROUND

Surgery may possibly be undermined by psychologic, psychiatric and psychosomatic problems, as long as these problems interfere with a patient's capacity to cope with surgery adaptively. Recent studies have shown that interpersonal trauma, e.g. abuse or neglect, and its correlates are involved in the adaptation to surgery. This observation is heuristically coherent, given the respective traumatization is an interpersonal event occurring in a relationship. Notably, surgery inevitably leads to the violation of physical boundaries within a doctor-patient relationship. Based on the principles of psycho-traumatologic thinking, such a constellation is deemed qualified to activate posttraumatic symptoms in the traumatized.

METHOD

The present topical review summarizes the respective findings which point to a subgroup of patients undergoing surgery, in whom difficulty bearing tension and confiding in others may cause adaptive problems relevant to surgery. Although this theorizing is empirically substantiated primarily with respect to total knee arthroplasty (TKA), a pubmed-research reveals psychopathologic distress to occur prior to surgery beyond TKA. Likewise, posttraumatic distress occurs in large numbers in the context of several operations, including cardiac, cancer and hernia surgery.

CONCLUSION

Aspects of psychological trauma may be linked to the outcomes of general surgery, as well, e.g. biliary, hernia or appendix surgery. The mechanisms possibly involved in this process are outlined in terms of a hierarchical organization of specific anxiety and negative affect as well as in terms of psychodynamics which imply the unconscious action of psychologic defenses at their core.

IMPLICATIONS

Not least, we encourage the screening for trauma and its correlates including defenses prior to general surgery in order to identify surgical candidates at risk of, e.g. chronic postoperative pain, before the operation.

Pain expectancy, prevalence, severity, and patterns following donor nephrectomy: Findings from the KDOC Study

Postoperative pain is an outcome of importance to potential living kidney donors (LKDs). We prospectively characterized the prevalence, severity, and patterns of acute or chronic postoperative pain in 193 LKDs at six transplant programs. Three pain measurements were obtained from donors on postoperative Day (POD) 1, 3, 7, 14, 21, 28, 35, 41, 49, and 56. The median pain rating total was highest on POD1 and declined from each assessment to the next until reaching a median pain-free score of 0 on POD49. In generalized linear mixed-model analysis, the mean pain score decreased at each pain assessment compared to the POD3 assessment. Pre-donation history of mood disorder (adjusted ratio of means [95% confidence interval (CI)]: 1.40 [0.99, 1.98]), reporting "severe" on any POD1 pain descriptors (adjusted ratio of means [95% CI]: 1.47 [1.12, 1.93]) and open nephrectomy (adjusted ratio of means [95% CI]: 2.61 [1.03, 6.62]) were associated with higher pain scores across time. Of the 179 LKDs who completed the final pain assessment, 74 (41%) met criteria for chronic postsurgical pain (CPSP), that is, any donation-related pain on POD56. Study findings have potential implications for LKD education, surgical consent, postdonation care, and outcome measurements.

Preoperative Assessment and Management of Patients with Pain and Anxiety Disorders

Purpose of Review

This review summarizes selected recent evidence on issues important for preoperative pain evaluation.

Recent Findings

Opioids, though a mainstay of postoperative pain management, are associated with both short and increasingly recognized long-term risks, including persistent opioid use. Risk factors for high levels of acute postoperative pain as well as chronic postsurgical pain may overlap, including psychological factors such as depression, anxiety, and catastrophizing. Tools to predict those at risk for poor postoperative pain outcomes are being studied.

Summary

Preoperative pain and psychological factors can affect postoperative pain outcomes. More work is needed in the future to develop practical interventions in the preoperative period to address these factors.

Management of neuropathic pain induced by surgery: Review of the literature by a group of experts specialized in pain management, anesthesia and surgery

Chronic postsurgical neuropathic pain (CPSNP) is frequent. While prevalence varies considerably according to type of operation and means of evaluation, it can reach 37% following breast surgery. Identification of risk factors related to the procedure and to the patient and taking into account the development of new, minimally invasive surgical techniques is increasingly nerve-sparing and reduces the likelihood of injury. CPSNP diagnosis in daily practice is facilitated by simple and quickly usable tools such as the NP4 4-question test. Management is based on pharmacological (analgesics, antiepileptics, antidepressants, local anesthetics) and non-pharmacological (kinesitherapy, neurostimulation, psychotherapy) approaches. In light of the present review of the literature, the authors, who constitute an expert group specialized in pain management, anesthesia and surgery, express their support for topical treatments (lidocaine, capsaicin) in treatment of localized postsurgical neuropathic pain in adults.

Expert Consensus on Clinical Use of an Orally Administered Dexketoprofen Plus Tramadol Fixed-Dose Combination in Moderate-To-Severe Acute Pain: A Delphi Study

INTRODUCTION

In 2016, the orally administered fixed-dose combination of dexketoprofen 25 mg and tramadol 75 mg (DKP/TRAM FDC) was approved in Europe for short-term treatment of moderate-to-severe acute pain, an indication that encompasses a wide range of post-operative and non-surgical painful conditions. This has suggested the necessity to have a clearer indication on its clinical use, with the support of expert pain clinicians, working in different medical specialities, and reinforced by the data present in the literature.

METHODS

With the aim of assisting clinicians in the use of DKP/TRAM FDC in daily practice, two rounds of a modified Delphi process were conducted. In the first round, a board of nine experts developed a series of consensus statements based on available evidence, and their clinical experience, with DKP/TRAM FDC. In the second round, 75 clinicians with extensive experience in pain management expressed individually their agreement with the statements, using a dedicated online platform. Consensus was defined as at least 70% agreement.

RESULTS

Twenty-eight statements were developed. Of these, 19 reached the defined level of consensus.

CONCLUSION

The agreed consensus statements may assist clinicians in applying the results of clinical studies and clinical experience to routine care settings, providing guidance for use of this new analgesic combination in moderate-to-severe post-operative and non-surgical acute pain.

FUNDING

Menarini Group.

Primary Role of the Amygdala in Spontaneous Inflammatory Pain- Associated Activation of Pain Networks - A Chemogenetic Manganese-Enhanced MRI Approach

Chronic pain is a major health problem, affecting 10–30% of the population in developed countries. While chronic pain is defined as “a persistent complaint of pain lasting for more than the usual period for recovery,” recently accumulated lines of evidence based on human brain imaging have revealed that chronic pain is not simply a sustained state of nociception, but rather an allostatic state established through gradually progressing plastic changes in the central nervous system. To visualize the brain activity associated with spontaneously occurring pain during the shift from acute to chronic pain under anesthetic-free conditions, we used manganese-enhanced magnetic resonance imaging (MEMRI) with a 9.4-T scanner to visualize neural activity-dependent accumulation of manganese in the brains of mice with hind paw inflammation. Time-differential analysis between 2- and 6-h after formalin injection to the left hind paw revealed a significantly increased MEMRI signal in various brain areas, including the right insular cortex, right nucleus accumbens, right globus pallidus, bilateral caudate putamen, right primary/secondary somatosensory cortex, bilateral thalamus, right amygdala, bilateral substantial nigra, and left ventral tegmental area. To analyze the role of the right amygdala in these post-formalin MEMRI signals, we repeatedly inhibited right amygdala neurons during this 2–6-h period using the “designer receptors exclusively activated by designer drugs” (DREADD) technique. Pharmacological activation of inhibitory DREADDs expressed in the right amygdala significantly attenuated MEMRI signals in the bilateral infralimbic cortex, bilateral nucleus accumbens, bilateral caudate putamen, right globus pallidus, bilateral ventral tegmental area, and bilateral substantia nigra, suggesting that the inflammatory pain-associated activation of these structures depends on the activity of the right amygdala and DREADD-expressing adjacent structures. In summary, the combined use of DREADD and MEMRI is a promising approach for revealing regions associated with spontaneous pain-associated brain activities and their causal relationships.

Genetic polymorphisms and prediction of chronic post-surgical pain after hysterectomy-a subgroup analysis of a multicenter cohort study

BACKGROUND

Chronic post-surgical pain (CPSP) is a serious problem. Clinical and psychological variables have not been able to explain all observed variance in prevalence and severity of CPSP. The first objective is to determine the association between genetic polymorphisms and the prevalence of CPSP after hysterectomy. The second objective is to analyze if the implementation of genetic polymorphisms into a previously performed clinical and psychological predictor analysis on the development of CPSP after hysterectomy will improve its discriminatory power.

METHODS

A prospective multicenter cohort study was performed in patients undergoing hysterectomy for benign indication. Clinical and psychological variables were collected by questionnaires in the week before surgery, post-operatively up to day 4, 3 and 12 months after hysterectomy. Blood was collected and 16 polymorphisms previously suggested to be correlated to CPSP (COMT, GCH1, KCNS1, CACNG2, and OPRM1) were genotyped. Logistic regression analyses were performed.

RESULTS

Three hundred and forty-five patients were available for the genetic analyses. The prevalence of CPSP 3 months post-operatively was 10.5% and after 12 months 7.9%. The polymorphism rs4818 within the COMT gene was associated with the prevalence of CPSP after 3 months. No polymorphisms were associated with CPSP after 12 months. The addition of rs4818 to the prediction model did not change its discriminatory power significantly.

CONCLUSION

The rs4818 polymorphism within the COMT gene was associated with the prevalence of CPSP 3 months after hysterectomy, but the implementation of rs4818 into the prediction model did not significantly improve the chance of identifying hysterectomy patients at risk for CPSP.

Chronic post-surgical pain after colon surgery in patients included in an enhanced recovery program

BACKGROUND

Enhanced recovery after surgery (ERAS) program improves immediate recovery. Beyond immediate benefits, long-term impact of ERAS implementation is not yet evident. This retrospective single-center cohort study investigates prevalence and characteristics of chronic post-surgical pain (CPSP) in patients who underwent colon surgery.

METHODS

Two hundred and ninety-seven patients enrolled prospectively in our ERAS database were contacted by mail to question the presence of CPSP. In case of CPSP, intensity, location, and type of pain, impact of pain on quality of life and treatment taken were assessed. Post-operative pain experience during hospital stay, recall of pain, and discomfort duration when back home were assessed in all patients. Comparison between patients with and without CPSP was made to approach the risk factors of CPSP in this population.

RESULTS

At 27 months after colon surgery, 25/198 patients reported CPSP (12.6%) and pain was severe in 5 patients (2.5%). CPSP had a deep abdominal component in 56% of patients and a parietal component in 20% of patients. Patients with CPSP+ differed from patients CPSP- for pre-operative pain presence (56% vs 24.8%, P = 0.004), recalled post-operative pain intensity (4 vs 3, P = 0.045), duration of discomfort after discharge (2 vs 1 weeks, P = 0.035). Pre-operative pain was found as a significant CPSP risk factor (odds ratio 1.34; 95% CI: 1.05-1.70).

CONCLUSION

CPSP prevalence after laparoscopic colon surgery seems not much affected by ERAS context. Pre-operative presence of pain emerged as an important risk factor. These findings should be confirmed in a prospective multicenter study.

The Influence of Race, Ethnicity and Genetic Variants on Postoperative Pain Intensity: An Integrative Literature Review

OBJECTIVES

Chronic postsurgical pain is pain that develops and persists for at least 3 months after a surgical procedure. The purpose of this review was to discover what evidence exists regarding the influence of race and ethnicity on postoperative pain intensity and what evidence exists regarding the influence of genetic polymorphisms on postoperative pain intensity.

DESIGN

Integrative literature review.

DATA SOURCES

CINAHL, PsychInfo, SCOPUS, and PubMed/Medline databases were searched for entries within the last 10 years. Sources included primary research investigating the relationship among race, ethnicity, and genetics in postoperative pain outcomes.

REVIEW/ANALYSIS METHODS

Studies adhered to a strict inclusion and exclusion criteria. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were utilized to evaluate and assess manuscripts for inclusion.

RESULTS

Twelve manuscripts were included for final review. There are significantly higher preoperative and postoperative pain intensity scores reported between African American and Hispanic individuals compared with non-Hispanic whites. Although some studies identified that non-Hispanic whites consumed more opioids and reported increased pain, there were no significant differences in opioid requirements in Hispanic and non-Hispanic individuals. COMT and OPRM1 were the most identified genetic polymorphisms associated with postoperative pain intensity.

CONCLUSIONS

The literature varies with respect to race, ethnicity, and postoperative pain perception. Perioperative pain intensity has been suggested as a significant predictor of chronic postsurgical pain. COMT and OPRM1 may be associated with higher pain perception after surgical procedures.

Inappropriate opioid prescription after surgery

Worldwide, the use of prescription opioid analgesics more than doubled between 2001 and 2013, with several countries, including the USA, Canada, and Australia, experiencing epidemics of opioid misuse and abuse over this period. In this context, excessive prescribing of opioids for pain treatment after surgery has been recognised as an important concern for public health and a potential contributor to patterns of opioid misuse and related harm. In the second paper in this Series we review the evolution of prescription opioid use for pain treatment after surgery in the USA, Canada, and other countries. We summarise evidence on the extent of opioid overprescribing after surgery and its potential association with subsequent opioid misuse, diversion, and the development of opioid use disorder. We discuss evidence on patient, physician, and system-level predictors of excessive prescribing after surgery, and summarise recent work on clinical and policy efforts to reduce such prescribing while ensuring adequate pain control.

Early postoperative neuropathic pain assessed by the DN4 score predicts an increased risk of persistent postsurgical neuropathic pain

BACKGROUND

Acute neuropathic pain can occur in the postoperative period but any link with persistent post-surgical neuropathic pain remains unclear.

OBJECTIVES

The objectives of this study were to prospectively describe the incidence of acute post-surgical neuropathic pain in a large population using the DN4 (clinician administered) questionnaire and to confirm the hypothetical link between acute and persistent neuropathic pain at 2 months after surgery in a large population using the DN2 (self administered) questionnaire.

DESIGN

A multi-centre, prospective and observational trial.

SETTING

Two consecutive days in 27 hospitals in France.

PATIENTS

Six hundred and eight patients undergoing 13 different types of surgery. Fifteen patients were excluded as data were incomplete, and 229 (38.6%) and 260 (43.8%) were not contactable for assessment at 1 and 2 months after surgery, respectively.

MAIN OUTCOME MEASURES

Pain was evaluated at least 2 h postoperatively on the same day (D0),on the second day (D2) and at 1 and 2 months after surgery (M1 and M2). Pain was assessed using a 10-point Numeric Rating Scale. If the Numeric Rating Scale score was greater than 0, neuropathic pain was assessed using a DN4 (clinician administered) questionnaire or using a DN2 (self-administered) questionnaire. Acute and persistent postsurgical neuropathic pain (PPSNP) were defined respectively by a DN4 score at least 4/10 on day 0 and/or day 2 and a DN2 score at least 3/7 at 2 months after surgery.

RESULTS

Of the 593 patients included, 41.2% were in pain before surgery and 8.2% described neuropathic pain. Early after surgery, the majority of the 593 patients (72.2% on the day of surgery and 71.3% on day 2) experienced acute pain. It was neuropathic in nature in 5.6% of patients (95% CI, 3.6 to 8.3) on the day of surgery and 12.9% (95% CI, 9.7 to 16.7) on day 2. Two months after surgery, PPSNP was present in 33.3% of the 333 patients assessed. Multivariate analysis showed that a DN4 score at least 4/10 on the day of surgery or on day 2 was a significant risk factor for PPSNP [odds ratios 4.22 (95% CI, 2.19 to 8.12)].

CONCLUSION

Our results suggest that early acute postsurgical neuropathic pain significantly increases the risk of persistent post-surgical neuropathic pain.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NTC NCT02826317.

Genetic polymorphisms and their association with the prevalence and severity of chronic postsurgical pain: a systematic review

BACKGROUND

Although several patient characteristic, clinical, and psychological risk factors for chronic postsurgical pain (CPSP) have been identified, genetic variants including single nucleotide polymorphisms have also become of interest as potential risk factors for the development of CPSP. The aim of this review is to summarize the current evidence on genetic polymorphisms associated with the prevalence and severity of CPSP in adult patients.

METHODS

A systematic review of the literature was performed, and additional literature was obtained by reference tracking. The primary outcome was CPSP, defined as pain at least 2 months after the surgery. Studies performed exclusively in animals were excluded.

RESULTS

Out of the 1001 identified studies, 14 studies were selected for inclusion. These studies described 5269 participants in 17 cohorts. A meta-analysis was not possible because of heterogeneity of data and data analysis. Associations with the prevalence or severity of CPSP were reported for genetic variants in the COMT gene, OPRM1, potassium channel genes, GCH1, CACNG, CHRNA6, P2X7R, cytokine-associated genes, human leucocyte antigens, DRD2, and ATXN1 CONCLUSIONS: Research on the topic of genetic variants associated with CPSP is still in its initial phase. Hypothesis-free, genome-wide association studies on large cohorts are needed in this field. In addition, future studies may also integrate genetic risk factors and patient characteristic, clinical, and psychological predictors for CPSP.

Multimodal analgesia in moderate-to-severe pain: a role for a new fixed combination of dexketoprofen and tramadol

BACKGROUND

Untreated and under-treated pain represent one of the most pervasive health problems, which is worsening as the population ages and accrues risk for pain. Multiple treatment options are available, most of which have one mechanism of action, and cannot be prescribed at unlimited doses due to the ceiling of efficacy and/or safety concerns. Another limitation of single-agent analgesia is that, in general, pain is due to multiple causes. Combining drugs from different classes, with different and complementary mechanism(s) of action, provides a better opportunity for effective analgesia at reduced doses of individual agents. Therefore, there is a potential reduction of adverse events, often dose-related. Analgesic combinations are recommended by several organizations and are used in clinical practice. Provided the two agents are combined in a fixed-dose ratio, the resulting medication may offer advantages over extemporaneous combinations.

CONCLUSIONS

Dexketoprofen/tramadol (25 mg/75 mg) is a new oral fixed-dose combination offering a comprehensive multimodal approach to moderate-to-severe acute pain that encompasses central analgesic action, peripheral analgesic effect and anti-inflammatory activity, together with a good tolerability profile. The analgesic efficacy of dexketoprofen/tramadol combination is complemented by a favorable pharmacokinetic and pharmacodynamic profile, characterized by rapid onset and long duration of action. This has been well documented in both somatic- and visceral-pain human models. This review discusses the available clinical evidence and the future possible applications of dexketoprofen/tramadol fixed-dose combination that may play an important role in the management of moderate-to-severe acute pain.

[Pain assessment of severely injured patients 2 years after trauma]

BACKGROUND AND OBJECTIVES

Trauma patients often suffer from persisting pain even years after injury, and data on long-term pain management is lacking. The aim of this study was to evaluate the frequency of persisting pain and health-related quality of life (HrQoL) among trauma victims 2 years after injury. Furthermore, the frequency of pain specialist consultation and the quality of outpatient pain management, including phamacological management, was assessed.

MATERIALS AND METHODS

We analyzed prospectively collected data on severely injured adult patients treated between 2008-2011 at the Cologne Merheim Medical Center (CMMC)/Germany.  Data included the 'Polytrauma Outcome Profile' and a standardized questionnaire on outpatient pain management. Exclusion criteria were death, inability to answer the questionnaire due to cognitive disabilities and lack of language knowledge.

RESULTS AND CONCLUSIONS

207/391 (53 %) data sets were available for analysis, presenting a typical trauma collective with injury severity of ISS 19, predominantly male and a mean age of 44 years. 2 years after trauma 59 % still reported that they suffered from severe persisting pain; 53 % of these patients were under pharmacological pain medication. Only 1/5 of the patients with severe persisting pain was treated by a pain specialist. Successful treatment options do exist; improvement of treatment is required.

Incidence and risk factors for rectal pain after laparoscopic rectal cancer surgery

Objective This study was performed to investigate the incidence of and potential risk factors for rectal pain after laparoscopic rectal cancer surgery. Methods We retrospectively analyzed data from 300 patients who underwent laparoscopic rectal cancer surgery. We assessed the presence of rectal pain and categorized patients into Group N (no rectal pain) or Group P (rectal pain). Results In total, 288 patients were included. Of these patients, 39 (13.5%) reported rectal pain and 14 (4.9%) had rectal pain that persisted for >3 months. Univariate analysis revealed that patients in Group P had more preoperative chemoradiotherapy, more ileostomies, longer operation times, more anastomotic margins of <2 cm from the anal verge, more anastomotic leakage, and longer hospital stays. Multivariate analysis identified an anastomotic margin of <2 cm from the anal verge and a long operation time as risk factors. The presence of diabetes mellitus was a negative predictor of rectal pain. Conclusions In this study, the incidence of rectal pain after laparoscopic rectal cancer surgery was 13.5%. An anastomotic margin of <2 cm from the anal verge and a long operation time were risk factors for rectal pain. The presence of diabetes mellitus was a negative predictor of rectal pain. Thus, the possibility of postoperative rectal pain should be discussed preoperatively with patients with these risk factors.

Predictors and trajectories of chronic postoperative pain following hip preservation surgery

Factors contributing to chronic postoperative pain (CPOP) are poorly defined in young people and developmental considerations are poorly understood. With over 5 million children undergoing surgery yearly and 25% of adults referred to chronic pain clinics identifying surgery as the antecedent, there is a need to elucidate factors that contribute to CPOP in surgical patients. The present study includes patients undergoing hip preservation surgery at a children's hospital. The HOOS and SF-12 Health Survey were administered to 614 pre-surgical patients with 421 patients completing follow-up (6-months, 1-year and 2-years post-surgery). Pain, quality of life, and functioning across time were examined for each group within the population. A three trajectory model (low pain, pain improvement and high pain) emerged indicating three categories of treatment responders. Pain trajectory groups did not differ significantly on gender, pre-surgical age, BMI, prior hip surgery, surgical type, joint congruence or Tönnis grade. The groups differed significantly from each other on pre-surgical pain, pain chronicity, quality of life and functioning. Those in the high pain and pain improvement groups endorsed having pre-surgical depression at significantly higher rates and lower pre-surgical quality of life compared to those in the low pain group (P < 0.01). Those in the high pain group reported significantly worse pre-surgical functioning compared to those in the pain improvement (P < 0.0001) and low pain groups (P < 0.0001).The results demonstrate the need for preoperative screening prior to hip preservation surgery, as there may be a subset of patients who are predisposed to chronic pain independent of hip health.