Assessment of Neuropathic Pain in Erosive Hand Osteoarthritis.

Background/Objectives: Erosive hand osteoarthritis (EHOA) is an aggressive form of hand osteoarthritis (OA) and a severely disabling condition. Patients affected by OA frequently lament symptoms suggestive of neuropathic pain (NP). The aim of our study was to ascertain the presence and severity of NP in patients with EHOA and correlate its presence with EHOA clinical characteristics. Methods: In this retrospective study, we included all consecutive EHOA patients with NP symptoms who underwent upper limb electroneurography (ENoG) and nerve ultrasound. The presence of NP was screened using the ID pain neuropathic pain-screening questionnaire (ID-Pain). In addition, the following NP questionnaires were also used: Douleur Neuropathique en 4 Questions (DN4), PainDETECT, and Neuropathic Pain Symptom Inventory (NPSI). Moreover, patients completed the Australian/Canadian Osteoarthritis Hand Index (AUSCAN) and Dreiser's algofunctional finger index questionnaires assessing EHOA disease activity. The following clinical and laboratory data were collected: age, sex, BMI, disease duration, intensity of pain (VAS 0-10), painful and swollen joints, and inflammatory indices, as well as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). Results: Of the 34 patients studied, 24 (70.6%) presented NP to the ID-Pain questionnaire. According to DN4, 14 (41.2%) patients had NP, while using the PainDETECT questionnaire, 67.6% had NP. Patients with NP were statistically younger and had a higher VAS pain score compared to subjects without NP. The ENoG and median nerve ultrasound were normal in 81% of patients, while four patients had carpal tunnel syndrome. The ID-Pain questionnaire correlated with the number of painful joints (r = 0.48, p = 0.03) and with the AUSCAN questionnaire (r = 0.37, p = 0.05). The DN4 questionnaire correlated with PainDETECT (r = 0.58, p < 0.01). The PainDETECT questionnaire correlated with VAS pain (r = 0.49, p = 0.02), the DN4 questionnaire (r = 0.58, p < 0.01), and AUSCAN (r = 0.51, p = 0.02). The NPSI questionnaire correlated negatively with BMI (r = -0.53, p = 0.01) and positively with the PainDETECT questionnaire (r = 0.49, p = 0.02). Conclusions: Our study revealed that 32% to 70% of EHOA patients exhibited symptoms consistent with NP, with observed variability depending on the questionnaire utilized. Despite patients frequently exhibiting symptoms compatible with NP, only 19% of patients presented alterations on ENoG and ultrasound examinations confirming CTS. This suggests a probable nociplastic component for pain in patients with EHOA, which warrants tailored treatment. In the present study, NP correlated with clinical and functional indices of EHOA.

Probiotic and high-fat diet: effects on pain assessment, body composition, and cytokines in male and female adolescent and adult rats.

Obesity in adolescence is increasing in frequency and is associated with elevated proinflammatory cytokines and chronic pain in a sex-dependent manner. Dietary probiotics may mitigate these detrimental effects of obesity. Using a Long-Evans adolescent and adult rat model of overweight (high-fat diet (HFD) - 45% kcal from fat from weaning), we determined the effect of a single-strain dietary probiotic [Lactiplantibacillus plantarum 299v (Lp299v) from weaning] on the theoretically increased neuropathic injury-induced pain phenotype and inflammatory cytokines. We found that although HFD increased fat mass, it did not markedly affect pain phenotype, particularly in adolescence, but there were subtle differences in pain in adult male versus female rats. The combination of HFD and Lp299v augmented the increase in leptin in adolescent females. There were many noninteracting main effects of age, diet, and probiotic on an array of cytokines and adipokines with adults being higher than adolescents, HFD higher than the control diet, and a decrease with probiotic compared with placebo. Of particular interest were the probiotic-induced increases in IL12p70 in female adolescents on an HFD. We conclude that a more striking pain phenotype could require a higher and longer duration caloric diet or a different etiology of pain. A major strength of our study was that a single-strain probiotic had a wide range of inhibiting effects on most proinflammatory cytokines. The positive effect of the probiotic on leptin in female adolescent rats is intriguing and worthy of exploration.NEW & NOTEWORTHY A single-strain probiotic (Lp299v) had a wide range of inhibiting effects on most proinflammatory cytokines (especially IL12p70) measured in this high-fat diet rat model of mild obesity. The positive effect of probiotic on leptin in female adolescent rats is intriguing and worthy of exploration.

Assessment of orofacial nociceptive behaviors of mice with the sheltering tube method: Oxaliplatin-induced mechanical and cold allodynia in orofacial regions.

Preclinical studies on pathological pain rely on the von Frey test to examine changes in mechanical thresholds and the acetone spray test to determine alterations in cold sensitivity in rodents. These tests are typically conducted on rodent hindpaws, where animals with pathological pain show reliable nocifensive responses to von Frey filaments and acetone drops applied to the hindpaws. Pathological pain in orofacial regions is also an important clinical problem and has been investigated with rodents. However, performing the von Frey and acetone spray tests in the orofacial region has been challenging, largely due to the high mobility of the head of testing animals. To solve this problem, we implemented a sheltering tube method to assess orofacial nociception in mice. In experiments, mice were sheltered in elevated tubes, where they were well accommodated because the tubes provided safe shelters for mice. Examiners could reliably apply mechanical stimuli with von Frey filament, cold stimuli with acetone spray, and light stimuli with a laser beam to the orofacial regions. We validated this method in Nav1.8-ChR2 mice treated with oxaliplatin that induced peripheral neuropathy. Using the von Frey test, orofacial response frequencies and nociceptive response scores were significantly increased in Nav1.8-ChR2 mice treated with oxaliplatin. In the acetone spray test, the duration of orofacial responses was significantly prolonged in oxaliplatin-treated mice. The response frequencies to laser light stimulation were significantly increased in Nav1.8-ChR2 mice treated with oxaliplatin. Our sheltering tube method allows us to reliably perform the von Frey, acetone spray, and optogenetic tests in orofacial regions to investigate orofacial pain.

An overview of diagnosis and assessment methods for neuropathic pain.

Neuropathic pain, defined as pain arising as a consequence of a lesion or disease affecting the somatosensory nervous system, requires precise diagnostic assessment. Different diagnostic tools have been devised for the diagnosis of neuropathic pain. This review offers insights into the diagnostic accuracy of screening questionnaires and different tests that investigate the somatosensory nervous system, in patients with suspected neuropathic pain. Thus, it illustrates how these tools can aid clinicians in accurately diagnosing neuropathic pain.

Neuropathic pain after surgery - A clinical validation study and assessment of accuracy measures of the 5-item NeuPPS scale.

OBJECTIVE: The aim of this study was to validate the Neuropathic Pain for Post-Surgical Patients (NeuPPS) scale against clinically verified neuropathic pain (NP) by quantitative sensory testing (QST) as well as evaluation of other psychometric properties. The NeuPPS is a validated 5-item scale designed to evaluate NP in surgical populations. METHODS: Data from 537 women aged >18 years scheduled for primary breast cancer surgery enrolled in a previous study for assessing risk factors for persistent pain after breast cancer treatment were used. Exclusion criteria were any other breast surgery or relevant comorbidity. A total of 448 eligible questionnaires were available at 6 months and 455 at 12 months. At 12 months, 290 patients completed a clinical examination and QST. NeuPPS and PainDETECT were analyzed against patients with and without clinically verified NP. NP was assessed using a standardized QST protocol including a clinical assessment. Furthermore, the NeuPPS and PainDETECT scores were psychometrically tested with an item response theory method, the Rasch analysis, to assess construct validity. Primary outcomes were the diagnostic accuracy measures for the NeuPPS, and secondary measures were psychometric analyses of the NeuPPS after 6 and 12 months. PainDETECT was also compared to clinically verified NP as well as NeuPPS comparing the stability of the estimates. RESULTS: Comparing the NeuPPS scores with verified NP using a receiver operating characteristic curve, the NeuPPS had an area under the curve of 0.80. Using a cutoff of 1, the NeuPPS had a sensitivity of 88% and a specificity of 59%, and using a cutoff of 3, the values were 35 and 96%, respectively. Analysis of the PainDETECT indicated that the used cutoffs may be inappropriate in a surgical population. CONCLUSION: The present study supports the validity of the NeuPPS as a screening tool for NP in a surgical population.

Sensitivity and Specificity of a Neuropathic Screening Tool (Self-Report Leeds Assessment of Neuropathic Symptoms and Signs, S-LANSS) in Adolescents With Moderate-Severe Chronic Pain.

Neuropathic screening tools improve recognition of neuropathic pain in adults. Although utilized in pediatric populations, the sensitivity, specificity and methodology of screening tool delivery have not been compared in children. We evaluated the Self-Report Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS) in adolescents (10-18 years) referred to a tertiary pediatric pain clinic. History and examination by specialist clinicians and multidisciplinary assessment informed classification of the primary pain type. In a prospective cohort, scores were obtained at interview (S-LANSS interview; n = 161, 70% female), and following substitution of self-reported signs with examination findings in the primary pain region (Leeds Assessment of Neuropathic Symptoms and Signs, LANSS examination). Secondly, we retrospectively retrieved questionnaires self-completed by adolescents at their initial clinic appointment (S-LANSS self-completed; n = 456, 73% female). Thirdly, we explored relationships between patient-reported outcomes and S-LANSS scores. S-LANSS interview scores varied with pain classification, and S-LANSS self-completed scores were similarly highest with neuropathic pain (median [interquartile range]: 18 [11, 21]) and complex regional pain syndrome (21 [14, 24]), variable with musculoskeletal pain (13 [7, 19]) and lowest with visceral pain (6.5 [2, 11.5]) and headache (8.5 [4, 14]). As in adults, the cutpoint score of 12/24 was optimal. Sensitivity was highest with inclusion of examination findings and lowest with self-completion (LANSS examination vs S-LANSS interview vs S-LANSS self-completed: 86.3% vs 80.8% vs 74.7%), but specificity was relatively low (37.8% vs 36.7% vs 48%). High S-LANSS scores in non-neuropathic groups were associated with female sex and high pain catastrophizing. The S-LANSS is a sensitive screening tool for pain with neuropathic features in adolescents, but needs to be interpreted in the context of clinical evaluation (clinicaltrials.gov NCT03312881). PERSPECTIVE: This article reports high sensitivity of the S-LANSS screening tool for identifying pain with neuropathic features in adolescents with moderate-severe chronic pain. However, as sensitivity is lower than in adult populations, further interdisciplinary evaluation is necessary to inform diagnosis and management.

Assessment of neuropathic pain following cancer treatment.

Neuropathic cancer pain (NCP) is prevalent affecting up to 58% of those with persistent pain following cancer treatment. Neuropathic pain can develop from malignancy, after neural tissue insult during surgery and/or exposure to radiation or neurotoxic agents used as part of cancer treatment regimens. Pain following cancer treatment is commonly under-treated and one barrier identified is poor recognition of pain and inadequate assessment. Recognition of the presence of NCP is important to inform pain management, which is challenging to treat and warrants the use of specific treatments to target neuropathic mechanisms. In this review, approaches for screening and classifying NCP are described. These include screening questionnaires and the application of the updated neuropathic pain grading system in a cancer context. The evidence from neuropathic pain related assessments in cancer populations is provided and highlighted under different neuropathic pain grades. Recommendations for assessment in practice are provided.

Pain with neuropathic characteristics after surgically treated lower limb fractures: Cost analysis and pain medication use.

Introduction: Neuropathic pain is prevalent among people after lower limb fracture surgery and is associated with lower health-related quality of life and greater disability. This study estimates the financial cost and pain medication use associated with neuropathic pain in this group. Methods: A secondary analysis using pain data collected over six postoperative months from participants randomised in the Wound Healing in Surgery for Trauma (WHiST) trial. Pain states were classified as pain-free, chronic non-neuropathic pain (NNP) or chronic neuropathic pain (NP). Cost associated with each pain state from a UK National Health Service (NHS) and personal social services (PSS) perspective were estimated by multivariate models based on multiple imputed data. Pain medication usage was analysed by pain state. Results: A total of 934 participants who provided either 3- or 6-months pain data were included. Compared to participants with NP, those with NNP (adjusted mean difference -£730, p = 0.38, 95% CI -2368 to 908) or were pain-free (adjusted mean difference -£716, p = 0.53, 95% CI -2929 to 1497) had lower costs from the NHS and PSS perspective in the first three postoperative months. Over the first three postoperative months, almost a third of participants with NP were prescribed opioids and 8% were prescribed NP medications. Similar trends were observed by 6 months postoperatively. Conclusion: This study found healthcare costs were higher amongst those with chronic NP compared to those who were pain-free or had chronic NNP. Opioids, rather than neuropathic pain medications, were commonly prescribed for NP over the first six postoperative months, contrary to clinical guidelines.

Exploring the prevalence, characteristics and nursing assessment of neuropathic pain.

Neuropathic pain results from damage to the nerves. It affects many in the general population, but its prevalence is higher in certain groups, for example those who have undergone certain procedures or systemic anti-cancer therapy and people with conditions such as diabetes mellitus, viral infections or central nervous system disorders. Regardless of the cause, neuropathic pain can have significant adverse effects on people's quality of life, so nurses need to be able to conduct a holistic pain assessment that incorporates physical, emotional, social and spiritual aspects. This article explores the prevalence, characteristics and nursing assessment of neuropathic pain with the aim of improving nurses' awareness, practice and care of people affected by this type of pain.

Joint European Academy of Neurology-European Pain Federation-Neuropathic Pain Special Interest Group of the International Association for the Study of Pain guidelines on neuropathic pain assessment.

BACKGROUND AND PURPOSE: In these guidelines, we aimed to develop evidence-based recommendations for the use of screening questionnaires and diagnostic tests in patients with neuropathic pain (NeP). METHODS: We systematically reviewed studies providing information on the sensitivity and specificity of screening questionnaires, and quantitative sensory testing, neurophysiology, skin biopsy, and corneal confocal microscopy. We also analysed how functional neuroimaging, peripheral nerve blocks, and genetic testing might provide useful information in diagnosing NeP. RESULTS: Of the screening questionnaires, Douleur Neuropathique en 4 Questions (DN4), I-DN4 (self-administered DN4), and Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) received a strong recommendation, and S-LANSS (self-administered LANSS) and PainDETECT weak recommendations for their use in the diagnostic pathway for patients with possible NeP. We devised a strong recommendation for the use of skin biopsy and a weak recommendation for quantitative sensory testing and nociceptive evoked potentials in the NeP diagnosis. Trigeminal reflex testing received a strong recommendation in diagnosing secondary trigeminal neuralgia. Although many studies support the usefulness of corneal confocal microscopy in diagnosing peripheral neuropathy, no study specifically investigated the diagnostic accuracy of this technique in patients with NeP. Functional neuroimaging and peripheral nerve blocks are helpful in disclosing pathophysiology and/or predicting outcomes, but current literature does not support their use for diagnosing NeP. Genetic testing may be considered at specialist centres, in selected cases. CONCLUSIONS: These recommendations provide evidence-based clinical practice guidelines for NeP diagnosis. Due to the poor-to-moderate quality of evidence identified by this review, future large-scale, well-designed, multicentre studies assessing the accuracy of diagnostic tests for NeP are needed.

Carbamazepine for Chronic Muscle Pain: A Retrospective Assessment of Indications, Side Effects, and Treatment Response.

Myopathies fall under the umbrella of rare diseases, however, muscle pain is a relevant, under-recognized symptom with limited treatment options. Carbamazepine is an oral sodium channel blocker approved for the treatment of seizures and neuropathic pain. In 54 individuals receiving carbamazepine for muscle pain, we retrospectively assessed the subjective treatment response, side effects, and reasons for carbamazepine discontinuation. The underlying diagnoses leading to muscle pain were diverse, ranging from metabolic (n = 5) and other hereditary (n = 9) to acquired (n = 2) myopathies and myotonia syndromes (n = 22). Under carbamazepine (daily dose 254 ± 138 mg), patients reported a significant reduction of pain, quantified by an 11-point numeric rating scale (−1.9 ± 1.8, p < 0.001). Compared to age- and sex-matched controls, our sensory assessment revealed a significant dysfunction of Aδ-nerve fibers in patients with chronic muscle pain. Neuropathic pain components identified by the painDETECT questionnaire or quantitative sensory testing did not seem to influence the reported treatment response. Side effects (n = 18) such as fatigue, elevated liver enzymes, and diarrhea, as well as lack of pain improvement (n = 6), led to carbamazepine discontinuation in 44.4% (24/54). Mediated by dysfunctional Aδ-nerve fibers, muscle pain is common in a variety of myopathies. Carbamazepine may reduce pain levels, but comes with therapy-limiting side effects.

[Assessment of neuropathic pain among women with suspected endometriosis based on two specific surveys]. / Évaluation de la douleur neuropathique en cas de suspicion d'endométriose à partir de deux questionnaires spécifiques.

OBJECTIVES: A significant proportion of women with suspected endometriosis present neuropathic pain. The aim of this study is to assess this prevalence and the relevance of specific tests used. METHODS: This is a single-center retrospective study in the CHI of Poissy Saint Germain en Laye with patients who were referred for suspected endometriosis and who benefited from evaluation of neuropathic pain by two distinct questionnaires. The PAINdetect was evaluated by a series of 7 questions scored from 0 to 5 with a positive test if score>18. For the DN4, 7 binary questions were asked and 3 other questions were related to the clinical examination with a positivity threshold reached if score≥4 and in the absence of clinical examination if score≥3. RESULTS: From November 2020 to June 2022, 57 patients were examined with a prevalence of neuropathic pain (one of the two test positive) evaluated at 36.8%. PAINdetect and DN4 positivity rates were at 26.8% and 30.9%. A discordance was found in 14.8% of cases with a kappa coefficient calculated at 0.63. There was a significant association between radiological examination and neuropathic pain with more neuropathic pain when the radiological examination was negative (P=0.03). The myofascial syndrome was present in only 59.5% of the patients and wasn't associated with neuropathic pain (P=1.00). CONCLUSION: Prevalence of neuropathic pain in case of suspected endometriosis appears to be high. This need to be confirmed in a multicenter study with also assessment of the validity of the two diagnostic tests.

Assessment of neuropathic pain, functional activity limitation and quality of life of people affected by leprosy in an endemic area in Northeast Brazil: a cross-sectional study.

BACKGROUND: This study investigated the prevalence of neuropathic pain (NP) among people affected by leprosy and its effects on functional limitation and health-related quality of life (HRQoL) in an endemic area in Northeast Brazil. METHODS: This is a cross-sectional study of 122 leprosy patients. Functional limitation and HRQoL were assessed using the Screening of Activity Limitation and Safety Awareness (SALSA) and WHO Quality-of-Life (WHOQoL-BREF) scales, respectively. Participants were assessed for the presence of pain and completed the Douleur Neuropathique 4 and the Brief Pain Inventory scales. RESULTS: The prevalence of NP was 59%. Participants with NP had higher SALSA scores than those without pain (median; IQR: 42; 32-49.5 vs 27.5; 24-34; p=0.002). Increasing SALSA scores were related to decreasing WHOQoL-BREF scores in the physical (r=-0.54; p<0.001), psychological (r=-0.33; p=0.002) and environmental (r=-0.22; p=0.01) domains, but not in the social domain (r=-0.14; p=0.10). Individuals with NP had the lowest scores in all domains compared with individuals without pain. CONCLUSIONS: Appropriate tools and training of clinicians for diagnosing NP in leprosy patients are necessary for their appropriate management and better HRQoL outcomes.

The assessment of neuropathic pain in patients with prediabetes.

AIMS: Neuropathic pain is associated with several clinical conditions, including anxiety, depression, sleep disorders, and decreased quality of life; however, less evaluated in prediabetes. This study aims to assess neuropathic pain through validated diagnostic tools in prediabetes. METHODS: One hundred and seventy-two patients with prediabetes and 170 controls were included in this cross-sectional study. The Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) Pain Scale and Douleur Neuropathique 4 Questions (DN4) were used to evaluate neuropathic pain. The Visual Analog Scale (VAS) was used to estimate pain intensity. RESULTS: Twenty-three (13.4%) and 12 (7%) patients with prediabetes were diagnosed with neuropathic pain using DN4 and LANSS questionnaires, respectively. Neuropathic pain rates of the patients were higher than controls with two pain scales (p < 0.001). VAS scores were higher in prediabetes group than in controls (p = 0.021). LANSS, DN4, and VAS scores were positively correlated with HbA1c level (r = 0.184, p = 0.016; r = 0.180, p = 0.018; r = 0.188, p = 0.014, respectively). LANNS and DN4 scores were higher in female patients than in males (p < 0.001). CONCLUSIONS: Neuropathic pain was increased in prediabetes by DN4 and LANNS questionnaires. An appropriate diagnosis of neuropathic pain in prediabetes may prevent patients from different pain-related clinical conditions.

Functional and morphometric assessment of small-fibre damage in late-onset hereditary transthyretin amyloidosis with polyneuropathy: the controversial relation between small-fibre-related symptoms and diagnostic test findings.

INTRODUCTION: We aimed at investigating whether functional and morphometric tests assessing small-fibre damage, ie quantitative sensory testing, Sudoscan and skin biopsy, reliably reflect neuropathic pain and autonomic symptoms in patients with late-onset hereditary transthyretin amyloidosis with polyneuropathy (ATTRv-PN). METHODS: In 30 patients with late-onset ATTRv-PN, we collected quantitative sensory testing, Sudoscan and skin biopsy with assessment of intraepidermal, piloerector muscle and sweat gland nerve fibre density. We then correlated these functional and morphometric parameters with neuropathic pain and autonomic symptoms as assessed with the Neuropathic Pain Symptom Inventory (NPSI) and Composite Autonomic Symptom Score-31 (COMPASS-31). RESULTS: 50% of patients showed small-fibre damage in the form of a pure small-fibre neuropathy, 47% in the context of a mixed fibre neuropathy with small and large fibre involvement. All patients complained of at least one autonomic symptom and 60% had neuropathic pain. Whereas quantitative sensory testing and Sudoscan parameters correlated with neuropathic pain and autonomic symptoms as assessed by NPSI and COMPASS-31, intraepidermal, piloerector muscle and sweat gland nerve fibre density quantification did not. CONCLUSIONS: Our findings indicate that functional test parameters reliably reflect neuropathic pain and autonomic symptoms related to small-fibre damage. These findings might help to identify clinically useful biomarkers to assess patient follow-up.

Screening trials of spinal cord stimulation for neuropathic pain in England-A budget impact analysis.

Screening trials of spinal cord stimulation (SCS) prior to full implantation of a device are recommended by expert guidelines and international regulators. The current study sought to estimate the budget impact of a screening trial of SCS and the costs or savings of discontinuing the use of a screening trial. A budget impact analysis was performed considering a study population that reflects the size and characteristics of a patient population with neuropathic pain in England eligible for SCS. The perspective adopted was that of the NHS with a 5-year time horizon. The base case analysis indicate that a no screening trial strategy would result in cost-savings to the NHS England of £400,000-£500,000 per year. Sensitivity analyses were conducted to evaluate different scenarios. If ≥5% of the eligible neuropathic pain population received a SCS device, cost-savings would be >£2.5 million/year. In contrast, at the lowest assumed cost of a screening trial (£1,950/patient), a screening trial prior to SCS implantation would be cost-saving. The proportion of patients having an unsuccessful screening trial would have to be ≥14.4% for current practice of a screening trial to be cost-saving. The findings from this budget impact analysis support the results of a recent UK multicenter randomized controlled trial (TRIAL-STIM) of a policy for the discontinuation of compulsory SCS screening trials, namely that such a policy would result in considerable cost-savings to healthcare systems.

Healthcare costs of post-traumatic trigeminal neuropathy in Belgium - A retrospective analysis.

The present aim was to estimate direct health care costs of patients suffering from post-traumatic trigeminal neuropathy (PTTN) and to compare the use of health care services, medications, and costs between temporary and persistent (>3 months) PTTN cohorts. A pre-existing clinical dataset of PTTN patients visiting a tertiary orofacial pain clinic in Belgium was utilized, including symptoms and quality of life measurements. Cost and resource utilization data were obtained by Belgium's largest health insurance provider for a period of 5 years after onset. Data from 158 patients was analyzed. The average cost per patient in the first year after injury was €2353 (IQR 1426-4499) with an out-of-pocket expense of 25% of the total cost. Hospitalization and technical interventions were the main drivers of cumulative costs, followed by consultation costs. For each cost category, expenditure was significantly higher in patients with persistent PTTN than in those with temporary PTTN (median 5-year total costs in persistent PTTN patients yielded €8866 (IQR 4368-18191) versus €4432 (IQR 2156-9032) in temporary PTTN, p <0.001) PTTN patients received repeated and frequent head and neck imaging (mean number of imaging investigations per patient was 10 ± 12). Medication consumption was high, with an unwarranted higher use of opioids and antibiotics in persistent PTTN patients. Within the limitations of this study, it seems there is a need for informing patients in detail on the inherent risks of nerve damage during dental and oromaxillofacial procedures. Every surgery should be preceded by a risk-benefit assessment in order to avoid unnecessary nerve damage.

Operant Self-medication for Assessment of Spontaneous Pain Relief and Drug Abuse Liability in Mouse Models of Chronic Pain.

The search for safe and efficient chronic pain treatments is dampened by the lack of reliable models that faithfully reproduce current pharmacological treatments for chronic spontaneous pain in humans. Preclinical models often assess the antinociceptive efficacy of non-contingent pharmacological treatments evaluated in the short-term. Here, we provide a protocol of contingent operant self-medication in mice, which allows the estimation of spontaneous pain relief and drug abuse liability in models of persistent pain. This paradigm requires preliminary habituation and animal handling, followed by training of mice in operant conditioning boxes, to allow subsequent analgesic drug self-administration. After the initial acquisition of food-maintained operant behavior, a chronic pain sensitization is induced. Posterior intravenous jugular catheterization and coupling of operant conditioning boxes to perfusion pumps allow quantification of operant responding for intravenous drug self-administration. All mice show an initial operant drug self-administration behavior associated with the previous food-maintained operant training. This initial operant responding is extinguished after administration of ineffective treatments, but continues when the compounds have analgesic efficacy or intrinsic reinforcing properties. The identification of a significant drug self-administration selectively expressed in mice exposed to the chronic pain condition is indicative of analgesic drug effects, whereas persistent self-administration in control mice is indicative of abuse liability. The present protocol provides the behavioral and surgical procedures needed to assess spontaneous pain relief and potential for abuse of pharmacological treatments, through contingent analgesic self-medication in mice. Graphic abstract: Experimental design. Animals are subjected to a 5-day food self-administration protocol with a fixed ratio of reinforcement of 1 (FR1, 1 interaction with the active nose-poke causes the release of 1 reinforcer/infusion), to acquire the operant behavior. After this training, mice are subjected to the chronic pain or sham procedure, and four days later an intravenous (i.v.) catheterization is performed, to allow self-administration with the selected compound or its vehicle. Three days after the catheterization, animals start the drug/vehicle self-administration protocol at FR1. The patency of the catheter is evaluated with the thiopental test after the last self-administration session. Adapted from Bura et al. (2018).

An overview of pain assessment and management.

Pain is a distressing, subjective and complex phenomenon that all nurses will encounter in their clinical practice. Effective pain management requires nurses to undertake a structured assessment to identify the probable causes of pain and guide management. Interventions used to reduce pain can be varied and multimodal. This article provides an overview of pain including its definition, classifications, assessment and management. It emphasises the importance of a person-centred approach to care which reflects Margo McCaffery's seminal quote that pain is 'whatever the experiencing person says it is'.