Volume 21, Issue 4

Objectives The pathogeneses of chronic tension-type headache (CTTH) and cervicogenic headache (CEH) are not well established. Peripheral activation or sensitization of myofascial nociceptors is suggested as a potential mechanism and injections of botulinum toxin (BONTA) have thus been used in the treatment for both headache conditions. BONTA inhibits the release of acetylcholine at the neuromuscular junction and inhibits contraction of skeletal muscles. If the pain is precipitated by increased tone in cervical muscles, local injections of BONTA could represent a prophylactic measure. However, the treatment is still controversial, and a thorough assessment of the current evidence is required. This review aims to assess the evidence of BONTA injection as a prophylactic treatment for CTTH and CEH by reviewing and examining the quality of placebo-controlled, randomized trials. Methods Data sources: we searched in the following databases: PubMed (including Medline), Embase, Cochrane Central register of Controlled Trials, Cinahl, Amed, SCOPUS and Google Scholar including other repository sources. Both MeSH and free keywords were used in conducting the systematic search in the databases. The search covered publications from the root of the databases to November 2020. Study eligibility criteria The review included RCTs, comparing single treatment of BONTA with placebo on patients with CTTH or CEH above 18 years of age, by measuring pain severity/relief or headache frequency. Data extraction The following data were extracted: year of publication, country, setting, trial design, number of participants, injection procedure, BONTA dosages, and clinical outcome measures. Study appraisal To assess validity and quality, and risk of bias, the Oxford Pain Validity Scale, Modified Jadad Scale, last version of Cochrane Collaboration’s tool for assessing risk of bias (RoB 2), and the CONSORT 2010 Checklist were used. The trials were assessed, and quality scored independently by two of the reviewers. A quantitative synthesis and meta-analyses of headache frequency and intensity were performed. Results We extracted 16 trials, 12 on prophylactic BONTA treatment for CTTH and four on CEH. Of these 12 trials (8 on CTTH and 4 on CEH) were included in the quantitative synthesis. A majority of the trials found no significant difference on the primary outcome measure when BONTA treatment was compared with placebo. Three “positive” trials, reporting significant difference in favor of BONTA treatment, but two of these were hampered by low validity and quality scores and high risk of bias. Conclusions There is no clear clinical evidence supporting prophylactic treatment with BONTA for CTTH or CEH.

Objectives Musculoskeletal pain is common among children and adolescents. Despite the lack of evidence regarding harms and benefits, musculoskeletal pain is often managed with pain medication. The aim of this systematic review is to assess the prevalence of pain medication use for musculoskeletal pain among children and adolescents and the factors and side effects associated with use. Content Three databases (EMBASE, CINAHL and PsychINFO) were systematically searched to identify studies designed to examine the prevalence, frequency or factors associated with the use of pain medication for musculoskeletal pain in children and adolescents (aged 6–19 years). The included studies were assessed for study quality and data were extracted. Summary The search initially provided 20,135 studies. After screening titles, abstracts and full-texts, 20 studies were included. In school settings, 8–42% of children used pain medication for musculoskeletal pain, and 67–75% of children in sports clubs and from pain clinics used pain medication. The most consistent factors associated with the use of pain medications were pain characteristics and psychological factors (e.g. being bullied, low-self-esteem), while mixed evidence was found for increasing age and female gender. Only two studies reported on the duration of use and only one study on adverse effects related to the use of pain medication. Outlook We found that 8–42% of adolescents from school-based samples use pain medication for MSK pain, while the prevalence among adolescents from sports clubs and pain clinics is higher (67–75%). Pain characteristics (pain duration, severity, intensity, disability levels and the presence of ≥2 pain conditions or multisite pain) and psychological factors were associated with a higher use of pain medication, while for higher age and female gender the evidence of association was mixed. Future studies should systematically collect information on the type, duration of use of pain medication and side effects to confirm the findings of this review.

Erector Spinae Plane Block (ESPB) was described by Forero in 2016. ESPB is currently widely used in acute postoperative pain management. The benefits of ESPB include simplicity and efficacy in various surgeries. The aim of this review was to conduct a comprehensive overview of available evidence on erector spinae plane block in clinical practice. We included randomized controlled trials and systematic reviews reporting the ESPB in human subjects. The review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Twenty-one articles including five systematic reviews and 16 randomized controlled trials were included and analyzed. ESPB appears to be an effective, safe, and simple method for acute pain management in cardiac, thoracic, and abdominal surgery. The incidence of side effects has been reported to be rare. A critical issue is to make sure that new evidence is not just of the highest quality, in form of well powered and designed randomized controlled trials but also including a standardized and homogeneous set of indicators that permit to assess the comparative effectiveness of the application of ESPB in acute interventional pain management.

Objectives Labour is one of the most painful experiences in a woman’s life. Epidural analgesia using low-concentration local anaesthetics and lipophilic opioids is the gold standard for pain relief during labour. Pregnancy in general, particularly labour, is associated with changes in maternal haemodynamic variables, such as cardiac output and heart rate, which increase and peak during uterine contractions. Adrenaline is added to labour epidural solutions to enhance efficacy by stimulating the α2-adrenoreceptor. The minimal effective concentration of adrenaline was found to be 2 μg mL −1 for postoperative analgesia. The addition of adrenaline may also produce vasoconstriction, limiting the absorption of fentanyl into the systemic circulation, thereby reducing foetal exposure. However, adrenaline may influence the haemodynamic fluctuations, possibly adding to the strain on the circulatory system. The aim of this study was to compare the haemodynamic changes after application of labour epidural analgesia with or without adrenaline 2 μg mL −1 . Methods This was a secondary analysis of a single-centre, randomised double-blind trial. Forty-one nulliparous women in labour requesting epidural analgesia were randomised to receive epidural solution of bupivacaine 1 mg mL −1 , fentanyl 2 μg mL −1 with or without adrenaline 2 μg mL −1 . The participants were monitored using a Nexfin CC continuous non-invasive blood pressure and cardiac output monitor. The primary outcomes were changes in peak systolic blood pressure and cardiac output during uterine contraction within 30 min after epidural activation. The effect of adrenaline was tested statistically using a linear mixed-effects model of the outcome variables’ dependency on time, adrenaline, and their interaction. Results After excluding three patients due to poor data quality and two due to a malfunctioning epidural catheter, 36 patients (18 in each group) were analysed. The addition of adrenaline to the solution had no significant effect on the temporal changes in peak systolic blood pressure (p = 0.26), peak cardiac output (0.84), or heart rate (p = 0.91). Furthermore, no significant temporal changes in maternal haemodynamics (peak systolic blood pressure, p=0.54, peak cardiac output, p=0.59, or heart rate p=0.55) were associated with epidural analgesia during 30 min after epidural activation in both groups despite good analgesia. Conclusions The addition of 2 μg mL −1 adrenaline to the epidural solution is not likely to change maternal haemodynamics during labour.

Objectives Breakthrough cancer pain (BTcP) is a transient exacerbation of pain that occurs over persistent, stable, and adequately controlled cancer background pain. It is prevalent and bears severe consequences to patients’ quality-of-life. The effective management of BTcP depends on fast and reliable (re)assessment. The Breakthrough pain Assessment Tool (BAT) is one of the most concise and reliable self-report instruments adapted to clinical contexts so far, showing good psychometric qualities in the United Kingdom, the Netherlands, and South Korea. As to promote the effective management of BTcP in Portuguese-speaking communities this study, first aimed to culturally adapt and validate the Portuguese version of the BAT (BAT-Pt). Second, and most importantly, it sought to provide novel evidence on its criterion validity by investigating its association with measures of psychological distress, which has not been yet investigated. Methods The BAT was translated into European Portuguese, using the back-translation method, and culturally adapted. Its psychometric properties (factor structure, internal consistency, construct and criterion validity) were analyzed in a cross-sectional multicenter study, with a sample of 65 cancer patients (49.2% women) recruited from eight hospitals in mainland Portugal ( a priori power analysis determined a minimum sample of 50). Health professionals collected patients’ clinical information, assessed their functional disability ( ECOG Performance Status ) and the adequacy of pain control. In addition to the Portuguese version of the BAT (BAT_Pt), patients completed the Portuguese versions of the Brief Pain Inventory , the Hospital Anxiety and Depression Scale , a Distress Thermometer and answered questions about the adequacy of pain control. Results The BAT-Pt was very well accepted by experts and patients. As hypothesized, a Principal Axis Factor Analysis revealed two underlying factors accounting for 55.2% of the variance: (1) Pain Severity and Impact of BTcP and (2) Duration of BTcP and Medication Inefficacy. Two items (on episode frequency and medication efficacy) were analyzed separately given their lower/cross loadings. The BAT-Pt showed good internal consistency overall ( α =0.79) and for each sub-scale, namely, Pain Severity and Impact of BTcP (n=5 items; α =0.86) and Duration of BTcP and Medication Inefficacy (n = 2 items; r sb =0.62). The BAT-Pt showed good convergent validity, being moderately to strongly associated with overall pain severity and interference (0.46<r<0.77, p<0.001). It also showed good concurrent validity by being associated not only with physical outcomes – such as functional disability (r=0.40, p<0.001) and patient- and physician-determined adequacy of BTcP control (|0.25<r pb <0.63|, p s <0.05) – but also, with distress (0.33<r<0.46, p s <0.001), anxiety (0.28<r<0.44, p s <0.05) and depression (r=0.47, p<0.001). Conclusions The BAT-Pt is a reliable and valid measure of breakthrough pain in Portuguese cancer patients and it is strongly associated to physical and psychological outcomes. This study confirms and extends the psychometric validation of the BAT to a new cultural context, promoting its diffusion and use by researchers and clinicians in Portuguese-speaking communities. The BAT-Pt may be an invaluable tool for daily clinical practice by tapping multiple aspects of BTcP experiences that are associated to patients’ physical and psychological outcomes.

Objectives Opioid analgesics are essential in clinical practice, but their excessive use is associated with addiction risk. Increases in opioid prescription rates have fuelled an epidemic of opioid addiction in the USA, making statistics on medical opioid use a critical warning signal. A dramatic 150% increase in Swedish opioid access 2001–2013 was recently reported based on data from the International Narcotics Control Board (INCB; Berterame et al. 2016) in conflict with other studies of opioid use in the Nordic countries. This article aims to analyse to what degree published INCB statistics on opioids in Scandinavia (Denmark, Norway and Sweden) reflect actual medical use and study the methodological reasons for putative discrepancies. Methods Data on aggregated total national sales of opioids for the whole population, including hospitals, were collected from the Swedish e-Health Authority. Total sales data for Denmark and drugs dispensed at pharmacies in Norway are publicly available through the relevant authorities’ websites. Results INCB opioid statistics during the period 2001–2013 were markedly inconsistent with sales data from Scandinavia, calling the reliability of INCB data into question. INCB-data were flawed by (a) over-representing the volume of fentanyl, (b) under-reporting of codeine, and (c) by not including tramadol. Conclusions Opioid availability, as expressed by INCB statistics, does not reflect medical opioid use. It is crucial to underline that INCB statistics are based on the manual compilation of national production, import and export data from manufacturers and drug companies. This is not the same amount that is prescribed and consumed within the health care system. Moreover, there are methodological problems in the INCB reports, in particular concerning fentanyl, codeine and tramadol. We suggest that INCB should carefully review the quality of their data on medical opioids.

Objectives Granisetron and lidocaine injections have been used for the management of myofascial pain syndrome. This study was aimed to compare the efficacy of granisetron and lidocaine injections to trigger points of upper trapezius in the management of myofascial pain syndrome. Methods We performed a double-blind randomized clinical trial in an outpatient clinic of physical medicine and rehabilitation at a teaching hospital. A total of 40 patients aged ≥18 with neck pain due to myofascial pain syndrome were included. They had pain for at least one month with the intensity of at least 30 mm on a 100 mm visual analog scale. Each participant received a single dose of 1 mL lidocaine 2% or 1 mg (in 1 mL) granisetron. The solutions were injected into a maximum of three trigger points of the upper trapezius. We instructed all patients to remain active while avoiding strenuous activity for three or four days, and to perform stretch exercise and massage of their upper trapezius muscles. We assessed the patients before the interventions, and one month and three months post-injection. The primary outcome was the Neck Disability Index and the secondary outcome was the Neck Pain and Disability Scale. Results Both interventions were successful in reducing neck pain and disability (all p-values <0.001). However, the neck pain and disability responded more favorably to lidocaine than granisetron (p=0.001 for Neck Disability Index, and p=0.006 for Neck Pain and Disability Scale). No significant side-effect was recognized for both groups. Conclusions Both lidocaine and granisetron injections to trigger points are effective and safe for the management of the syndrome and the benefits remain at least for three months. However, lidocaine is more effective in reducing pain and disability. The injections are well-tolerated, although a transient pain at the site of injections is a common complaint. One mL of lidocaine 2% is more effective than 1 mg (in 1 mL) granisetron for injecting into the trigger points of the upper trapezius in myofascial pain syndrome.

Objectives This 10-year follow-up study aimed to examine the persistence of SF-36 pain intensity and pain-related interference and to identify baseline factors that may relate to pain experience among community-dwelling aging adults. Methods Questionnaire and clinical data on a total of 1,954 participants (mean age at baseline 63 years) were collected in 2002, 2005, 2008, and 2012. Based on pain reports, four pain intensity, pain interference (PIPI) groups were formed at each time point: PIPI group I: none to mild pain intensity and interference; II: moderate to extreme pain intensity, none to mild pain-related interference; III: None to mild pain intensity, moderate to extreme pain-related interference, IV: Moderate to extreme pain intensity and interference. Results Participants with the most pain at baseline improved their pain situation the most during the follow-up. Higher BMI was associated with pain interference, and metabolic syndrome (MetS) and musculoskeletal diseases with both pain intensity and interference (p<0.05, statistically significant interaction between pain intensity and pain interference) at baseline. According to multivariate logistic regression analysis the following baseline characteristics were associated with remaining in PIPI group I throughout the follow-up: presence of musculoskeletal disease (OR 0.22 [95% CI 0.16–0.30]), high BMI (OR 0.93 [95% CI 0.90–0.97]), high household income (OR 1.46 [95% CI 1.07–1.98]), good childhood home environment (OR 1.03 [95% CI 1.00–1.05]). Conclusions Multiple factors may affect pain persistence in late adulthood with varying effect on pain intensity and pain-related interference. Pain situation of even those with most pain may be improved.

Objectives Insomnia is commonly comorbid with chronic pain, and typically leads to worse outcomes. Two factors that could contribute to a cycle of pain and sleeplessness are pre-sleep cognitive arousal (repetitive thought processes) and low mood. This study aimed to examine how pain, sleep disturbance, mood, and pre-sleep cognitive arousal inter-relate, to determine whether low mood or pre-sleep cognitive arousal contribute to a vicious cycle of pain and insomnia. Methods Forty seven chronic pain patients completed twice daily diary measures and actigraphy for one week. Analyses investigated the temporal and directional relationships between pain intensity, sleep quality, time awake after sleep onset, anhedonic and dysphoric mood, and pre-sleep cognitive arousal. Fluctuations in predictor variables were used to predict outcome variables the following morning using mixed-effects modelling. Results For people with chronic pain, an evening with greater pre-sleep cognitive arousal (relative to normal) led to a night of poorer sleep (measured objectively and subjectively), lower mood in the morning, and a greater misperception of sleep (underestimating sleep). A night of poorer sleep quality led to greater pain the following morning. Fluctuations in pain intensity and depression did not have a significant influence on subsequent sleep. Conclusions For people with chronic pain, cognitive arousal may be a key variable exacerbating insomnia, which in turn heightens pain. Future studies could target cognitive arousal to assess effects on sleep and pain outcomes.

Objectives The use of the Injustice Experience Questionnaire (IEQ) in psychological assessment of individuals with chronic pain is supported by research. The psychometric properties of the Swedish version, the IEQ-S, has not yet been evaluated. Hence, the aim was to investigate structural validity, and concurrent criterion validity of the IEQ-S against the Work Ability Index (WAI), the Pain Catastrophizing Scale (PCS-SW), the Patient Health Questionnaire 9-item depression module (PHQ-9), and the Generalized anxiety disorder 7-item scale (GAD-7). Internal consistency and test-retest reliability were also studied. Methods Sixty-five participants, referred to a University hospital, with a pain duration over three months were consecutively sampled. They completed the IEQ-S at admission and again within six weeks. A confirmatory factor analysis was performed for the study of structural validity. Concurrent criterion validity was evaluated using Spearman’s correlation coefficient. Internal consistency reliability for the full IEQ-S was calculated using the Cronbach’s alpha. Test-retest reliability was calculated using an Intraclass Correlation Coefficient (ICC). Results The median total score (0–48, where high scores indicate high levels of injustice) at admission (test 1) was 27.0 (n=64), 25th percentile=15.3, 75th percentile=37.8, range=3–48 points. A one-factor model was supported with item-loadings between 0.67–0.92. Spearman’s correlation coefficient between the IEQ-S and the WAI (n=56) was r S =−0.46; the PCS-SW (n=63) was r S =0.68, the PHQ-9 (n=64) was r S =0.50 and the GAD-7 (n=64) was r S =0.57, p<0.01. Cronbach’s alpha was 0.94 (n=64). The ICC was 0.80 (n=55), with a 95% confidence interval, ranging between 0.69–0.88. Conclusions Our study supported structural validity and concurrent criterion validity of the IEQ-S against other measures of psychological constructs and work ability. It also supported the internal consistency reliability of the IEQ-S and the test-retest reliability with a retest interval up to six weeks, was good. These findings support the use of the IEQ-S as an adjunct tool to assess appraisals of injustice in patients with chronic pain who are referred to tertiary care in Sweden. The added value might be identification of those who are at risk for slow or no improvement in their pain condition over time, and sick-leave, but this has to be confirmed in future studies. Ethical committee number EPN Uppsala D-No 2016-376.

Objectives A fundamental principle of pain management is educating patients on their pain using current neuroscience. However, current pain neurophysiology education (PNE) interventions show variable success in improving pain outcomes, and may be difficult to integrate with existing understanding of pain. This study aimed to investigate how people with chronic pain understand their pain, using qualitative exploration of their conceptualisations of pain, and how this understanding accommodated, or resisted, the messages of PNE. Methods Twelve UK adults with chronic pain were recruited through advertisements on online pain networks. Semi-structured interviews were conducted remotely, with responses elicited using the Grid Elaboration Method (GEM) and then a PNE article. Participants’ grid elaborations and responses to PNE were analysed using thematic analysis (TA). Results Three main themes were extracted from participants' grid elaborations: communicating pain, explaining pain and living with pain. These themes incorporated varied, inconsistent sub-themes: of pain as simultaneously experiential and conceptual; in the body and in the mind; diagnosable and inexplicable; manageable and insuperable. Generalised, meta-level agreement was identified in participants' PNE responses, but with doubts about its practical value. Conclusions This study shows that people understand pain through inconsistent experiential models that may resist attempts at conceptual integration. Participants' elaborations showed diverse and dissonant conceptualisations, with experiential themes of restricted living; assault on the self; pursuit of understanding pain and abandonment of that pursuit. Responses, although unexpectedly compatible with PNE, suggested that PNE was perceived as intellectually engaging but practically inadequate. Experiential disconfirmation may be required for behavioural change inhibited by embedded fears and aversive experiences. Ethical committee number UCL REC# 17833/003.

Objectives In patients with multiple sclerosis (MS), a relationship between physical disability and pain has been observed. In addition a relationship between physical disability and cognition in MS has been suggested. However, cognitive functions and pain appear not to be correlated in MS patients. Therefore, we examined whether a possible relationship between pain and cognitive functioning may exist, and if so, if such a relationship is mediated by physical disability. Methods Forty-five MS patients with chronic pain, and in an advanced stage of the disease were included. Physical disabilities were assessed by the Expanded Disability Status Scale (EDSS). Episodic memory was assessed by means of the Eight Words test, and Face and Picture Recognition. Executive functions (EF) were examined by Digit Span Backward for working memory, and the Rule Shift Cards and Category Fluency test for cognitive flexibility. Pain Intensity and Pain Affect were assessed by means of visual analogue scales and one verbal pain scale and mood (depression, anxiety) by the Beck Depression Inventory and the Symptom Check List (SCL-90). The research questions were analyzed by means of regression analyses and the Sobel test for mediation. Results A significant relationship was found between Pain Affect and EF, but that relationship was not mediated by physical disabilities (EDSS). In addition, Pain Intensity and EF showed a significant relationship but only in combination with physical disabilities (EDSS). Finally, mood was related to pain affect. Discussion The findings suggest that the lower the EF, exclusively or in combination with more physical disabilities, the more the patient may suffer from pain. Implications The more one is cognitively and physically impaired, the more one might suffer from pain, and, the less one is able to communicate pain. The latter could put MS patients at risk for underdiagnosing and undertreatment of pain.

Objectives This observational study aimed to assess the difference in disability, burden, and sensitization between migraine patients with low-frequency headache attack (1–8 headache days/month), high-frequency headache attack (9–14 headache days/months), and patients with chronic migraine (>14 headache days/months). Methods Migraine patients with or without aura were divided into three groups according to headache frequency (low-frequency episodic migraine; high-frequency episodic migraine; chronic migraine). Questionnaires were used to assess the burden of headache, quality of life, phycological burden, and symptoms related to sensitization (estimated by the Central Sensitization Inventory). Differences among migraine groups were assessed using Chi-Quadro test, ANOVA, or Kruskal–Wallis as appropriate. Results 136 patients were included (68 low-frequency episodic migraine, 45 high-frequency episodic migraine, 23 chronic migraine). Patients with high frequency episodic migraine and chronic migraine differed from patients with low frequency episodic migraine showing a worse burden of headache (p=0.002; p=0.002), worse level of physical (p=0.001; p<0.001) and mental (p=0.002; p=0.001) quality of life, worse level of depression (p=0.008; p=0.003), and increase presence of symptoms related to sensitization (p<0.001; p=0.003). No differences were found in any variables between patients with high-frequency episodic migraine and patients with chronic migraine (p>0.05). Conclusions Patients with high-frequency episodic migraine and chronic migraine could be considered in the same segment of the migraine population, with similar degrees of disability and sensitization related symptoms.

Objectives Tension-type headache (TTH) is the most prevalent primary headache disorder. We assessed the cross-sectional impact of TTH on health related quality of life (HRQoL) in a general population. We also examined the association of HRQoL scores with headache frequency, disability, medication overuse, poor self-rated health, psychiatric comorbidity, and pain sensitivity in individuals with TTH. Methods A sample of 547 subjects completed a headache diagnostic interview, the SF-12 to calculate physical (PCS) and mental (MCS) health component scores, depression (major depression inventory [MDI]) and neuroticism (Eysenck Personality Questionnaire) measures. We defined the following headache diagnosis categories: pure TTH, pure migraine, and coexistent headache (TTH + migraine). Cases were further classified into chronic (≥15) or episodic (<15 headache days/month). Results Using generalized linear models (GLM) adjusted for age, sex and education, both PCS-12 and MCS-12 scores varied in groups distinguished by migraine and TTH status; scores were lower for individuals with coexistent headache (TTH + migraine; n=83), followed by pure TTH (n=97) and pure migraine (n=43) compared to the no headache group (n=324) (p≤0.001). In analyses considering chronicity, PCS-12 scores were lower in chronic coexistent headache followed by pure chronic TTH (CTTH), episodic migraine +/− episodic TTH (ETTH) and pure ETTH than in the no headache group (p≤0.001). MCS-12 scores were lower in pure CTTH, followed by chronic coexistent headache, episodic migraine +/− ETTH and pure ETTH compared to the no headache group (p≤0.001). Multiple regression models showed that in TTH, lower PCS-12 scores were associated with age (p=0.04), female sex (p=0.02), and poor self-rated health (p≤0.001). Lower MCS-12 scores in TTH were associated with depression (p≤0.001). Conclusions In a population sample, TTH, and to higher degree CTTH, are associated with decreased HRQoL.

Objectives Patients with facial pain are sometimes referred for neurosurgical treatment with a poorly documented diagnosis of trigeminal neuralgia. In such cases, neurosurgery will usually not be helpful. We conducted a re-evaluation of the diagnosis in patients referred for neurosurgical treatment of presumed trigeminal neuralgia. Our objective was to find out why and how often misdiagnosis occurred. Methods A retrospective study was done in consecutive first-time patients referred for trigeminal neuralgia to our outpatient clinic in 2019. We used five ICHD-3-based clinical criteria to verify or exclude the diagnosis. In patients where trigeminal neuralgia was excluded, we established a diagnosis for their facial pain based upon medical history and a physical examination by a neurosurgeon – often supplemented with examination by an oral surgeon. Results Thirty-eight patients were referred for presumed trigeminal neuralgia. Only 17 of them fulfilled the five criteria and were diagnosed with trigeminal neuralgia. In 20 of the remaining 21 patients trigeminal neuralgia could be clearly excluded, while one of the patients had a periodontitis closely mimicking trigeminal neuralgia. In 14 of the 21 patients we diagnosed temporomandibular dysfunction or dental conditions. MRI scans had detected low-grade neurovascular contacts in 13 of the 21 patients, a finding that was clearly overestimated by the referring neurologists in seven patients. Conclusions Overdiagnosis of trigeminal neuralgia was common in patients referred for neurosurgery, mostly due to insufficient clinical evaluation combined with an overestimation of MRI-detected NVCs. The clinical diagnosis should be critically re-evaluated before recommending neurosurgery to patients referred for presumed trigeminal neuralgia.

Objectives Continuous peripheral nerve blocks (cPNBs) have shown promising results in pain management after orthopaedic surgeries. However, they can be associated with some risks and limitations. The purpose of this study is to describe our experience with the cPNBs regarding efficacy and adverse events in patients undergoing orthopedic surgeries on the lower extremity in different subspecialties. Methods This is a prospective cohort study on collected data from perineural catheters for pain management after orthopedic surgeries in lower limbs. Catheters were placed by experienced anesthesiologists using sterile technique. After an initial bolus dose of 10–20 mL ropivacaine 0.5% (weight adjusted), the catheters were secured and connected to disposable mechanical infusion pumps with ropivacaine 0.2% (basal infusion rate = 6 mL/h; weight adjusted (0.2 mL/kg/h)). After catheterization, the patients were examined daily, by specially educated acute pain service nurses. Pro re nata (PRN) or fixed boluses (10 mL bupivacaine 0.25%; weight adjusted) with an upper limit of 4 times/day, were administered if indicated. Patients’ demographic data, physiological status, and pre-op intake of opioids and other analgesics were registered. The severity of post-operative pain was assessed with ‘Numeric Rating Scale’ (NRS) and ‘Face, legs, Activity, Cry, Consolability’ (FLACC) scale for adults and children, respectively. The need for additional opioids and possible complications were registered. Results We included 547 catheters of 246 patients (Range 1–10 catheters per patient). Overall, 115 (21%) femoral, 162 (30%) saphenous, 66 (12%) sciatic, and 204 (37%) popliteal sciatic nerve catheter were used. 452 (83%) catheters were inserted by a primary procedure, 61(11%) catheters employed as a replacement, and 34 catheters (6.2%) used as a supplement. For guiding the catheterization, ultrasound was applied in 451 catheters (82%), nerve stimulator in 90 catheters (16%), and both methods in 6 catheters (1.1%). The median duration a catheter remained in place was 3 days (IQR = 2–5). The proportion of catheters with a duration of two days was 81, 79, 73, and 71% for femoral, sciatic, saphenous, and popliteal nerve, respectively. In different subspecialties, 91% of catheters in wound and amputations, 89% in pediatric surgery, 76% in trauma, 64% in foot and ankle surgery, and 59% in limb reconstructive surgery remained more than two days. During first 10 days after catheterization, the proportion of pain-free patients were 77–95% at rest and 63–88% during mobilization, 79–92% of the patients did not require increased opioid doses, and 50–67% did not require opioid PRN doses. In addition to 416 catheters (76%), which were removed as planned, the reason for catheter removal was leaving the hospital in 27 (4.9%), loss of efficacy in 69 (13%), dislodgement in 23 (4.2%), leakage in 8 (1.5%), and erythema in 4 catheters (0.73%). No major complication occurred. Conclusions After orthopaedic procedures, cPNBs can be considered as an efficient method for improving pain control and minimizing the use of additional opioids. However, the catheters sometimes might need to be replaced to achieve the desired efficacy.

Objectives Targeted corticosteroid injections (CSI) are one of the treatments that can provide pain relief and thereby, enhance quality of life in patients with chronic pain. Corticosteroids (CS) are known to impair immune response. The objective was to evaluate the risk of developing post-procedural infection within 4 weeks of receiving depot CSI for chronic pain as part of on going quality improvement project. We hypothesised that interventional treatment with depot steroids will not cause a significant increase in clinical infection in the first 4 weeks. Methods Telephone follow-up was performed as a part of prospective longitudinal audit in a cohort of patients who received interventional treatment for chronic pain at a multidisciplinary pain medicine centre based at a university teaching hospital. Patients who received interventional treatment in the management of chronic pain under a single physician between October 2019 and December 2020 were followed up over telephone as part of on going longitudinal audits. Data was collected on any infection within 4 and 12 weeks of receiving the intervention. Outcomes collected included type of intervention, dose of depot steroids and pain relief obtained at 12 weeks following intervention. Results Over a 15 month period, 261 patients received pain interventions with depot CS. There was no loss to follow-up. Nine patients reported an infection within 4 weeks of receiving depot steroids (9/261, 3.4%). None of the patients tested positive for Covid-19. Eight patients (8/261, 3%) reported an infection between 5 and 12 weeks following the corticosteroid intervention. Although none of the patients tested positive for Covid-19, two patients presented with clinical and radiological features suggestive of Covid-19. Durable analgesia was reported by 51% (133/261) and clinically significant analgesia by 30% (78/261) at 12 weeks following the intervention. Failure rate was 19% (50/261). Conclusions Pain medicine interventions with depot steroids do not appear to overtly increase the risk for Covid-19 infection in the midst of a pandemic.

Objectives Low back pain (LBP) is the leading cause of disability and a global public health concern. Studies indicate that pain self-efficacy is associated with the development of disability in chronic LBP (CLBP) patients. The Pain Self-Efficacy Questionnaire (PSEQ) is a commonly used questionnaire to assess pain self-efficacy in patients with CLBP. It is essential to examine the psychometric properties of the PSEQ in the population in which it is to be used. Thus, the aim of this study is to evaluate the reliability and smallest detectable change of the Danish version of the Pain Self-Efficacy Questionnaire (PSEQ-DK) in patients with CLBP before implementing it as an outcome measure in an inpatient rehabilitation context. Methods This observational study including 92 patients with CLBP was conducted in a multidisciplinary rehabilitation facility in Denmark. The psychometric properties statistically tested included reliability, smallest detectable change and floor and ceiling effect of the PSEQ-DK. Results The reliability analysis included 92 patients and revealed an weighted kappa of 0.82 (95% Cl 0.75; 0.88) and Intraclass correlation coefficient of 0.83 (95% CI 0.75; 0.88), which corresponds to a good reliability. The smallest detectable change was 12.67. Conclusions The present study demonstrated that the PSEQ-DK had a good reliability in patients with CLBP in an inpatient rehabilitation context. The current results expand our knowledge of the reliability and smallest detectable change of the PSEQ-DK. In order to implement PSEQ-DK in a rehabilitation context for evaluative purposes future studies should focus on examining responsiveness and interpretability.

Objectives The association between an individuals’ demographic and health characteristics and the presence of multiple chronic conditions is not well known among older United States (US) adults. This study aimed to identify the prevalence and associations of having multiple chronic conditions among older US adults with self-reported pain. Methods This retrospective, cross-sectional study used data from the 2017 Medical Expenditure Panel Survey. Study subjects were aged ≥50 years and had self-reported pain in the past four weeks. The outcome variable was multiple (≥5) chronic conditions (vs. <5 chronic conditions). Hierarchical logistic regression models were used to identify significant associations between demographic and health characteristics and multiple chronic conditions with significance indicated at an a priori alpha level of 0.05. The complex survey design was accounted for when obtaining nationally-representative estimates. Results The weighted population was 57,074,842 US older adults with pain, of which, 66.1% had ≥5 chronic conditions. In fully-adjusted analyses, significant associations of ≥5 comorbid chronic conditions included: age 50–64 vs. ≥65 years (adjusted odds ratio [AOR]=0.478, 95% confidence interval [CI]=0.391, 0.584); male vs. female gender (AOR=1.271, 95% CI=1.063, 1.519); white vs. other race (AOR=1.220, 95% CI=1.016, 1.465); Hispanic vs. non-Hispanic ethnicity (AOR=0.614, 95% CI=0.475, 0.793); employed vs. unemployed (AOR=0.591, 95% CI=0.476, 0.733); functional limitations vs. no functional limitations (AOR=1.862, 95% CI=1.510, 2.298); work limitations vs. no work limitations (AOR=1.588, 95% CI=1.275, 1.976); little/moderate vs. quite a bit/extreme pain (AOR=0.732, 95% CI=0.599, 0.893); and excellent/very good (AOR=0.375, 95% CI=0.294, 0.480) or good (AOR=0.661, 95% CI=0.540, 0.810) vs. fair/poor physical health. Conclusions Approximately 38 million of the 57 million US older adults with pain in this study had ≥5 chronic conditions in 2017. Several characteristics were associated with multiple chronic conditions, which may be important for health care professionals to consider when working with patients to manage their pain. This study was approved by The University of Arizona Institutional Review Board (2006721124, June 12, 2020).

Objectives The incidence of chronic postoperative pain after total knee replacement (TKR) is approx. 20%, and hence preoperative risk factors are important to identify. Recent studies have indicated that preoperative inflammatory markers might hold prognostic information for the development of chronic postoperative pain. Long non-coding RNA (lncRNA) regulates the expression of genes related to e.g. inflammatory processes. The current study aimed to investigate the preoperative lncRNA signature as possible preoperative predictive markers for chronic postoperative pain following TKR. Methods Serum samples, collected preoperatively from 20 knee osteoarthritis (KOA) patients, were analyzed for 84 validated circulatory lncRNA. Pain intensity was assessed using a visual analog scale (VAS) before and one-year after TKR. Differences for the lncRNA expression were analyzed between patients with chronic postoperative pain (VAS≥3) and those with a normal postoperative recovery (VAS<3). Results LncRNA Myeloid Zinc Finger 1 Antisense RNA 1 (MZF1-AS1) (fold change −3.99; p-value: 0.038) (shown to be involved neuropathic pain) Metastasis associated lung adenocarcinoma transcript 1 (MALAT1) (fold change −3.39; p-value: 0.044) (shown to be involved neuropathic pain); Patched 1 pseudogene (LOC100287846) (fold change −6.99; p-value: 0.029) (unknown in pain) were down-regulated preoperatively in the group with chronic postoperative pain compared to the group normal postoperative pain recovery. Conclusions These findings suggest, that TKR patients with chronic postoperative pain present preoperative downregulations of three specific lncRNA detectable at the systemic level. The presented study might give new insights into the complexity of chronic postoperative pain development and show how non-coding RNA plays a role in the underlying molecular mechanisms of pain.

Objectives There is no effective evidence-based non-pharmacological treatment for severe neuropathic pain after spinal cord injury (SCI). Paired associative stimulation (PAS) has been used in motor rehabilitation of patients after SCI. In the SCI-PAS protocol for tetraplegic patients, peripheral and central nerve tracts are activated with subject-specific timing, such that ascending and descending signals appear simultaneously at the cervical level. The effect on motor rehabilitation is thought to arise via strengthening of cervical upper and lower motoneuron synapses. We have observed an analgesic effect of PAS on mild-to-moderate neuropathic pain in tetraplegic patients receiving PAS for motor rehabilitation. Here, we applied PAS to a patient with severe drug-resistant neuropathic pain. Methods The patient is a 50-year-old man who had a traumatic cervical SCI three years earlier. He has partial paresis in the upper limbs and completely plegic lower limbs. The most severe pain is located in the right upper limb and shoulder region. The pain has not responded to either pharmacological therapy or repetitive-TMS therapy targeted to either primary motor cortex or secondary somatosensory cortex. PAS was targeted to relieve pain in the right upper arm. Peripheral nerve stimulation targeted the median, ulnar, and radial nerves and was accompanied by TMS pulses to the motor representation area of abductor pollicis brevis, abductor digiti minimi, and extensor digitorum communis muscles, respectively. Results Hand motor function, especially finger abduction and extension, was already enhanced during the first therapy week. Pain decreased at the end of the second therapy week. Pain was milder especially in the evenings. Numerical rating scale scores (evening) decreased 44% and patient estimation of global impression of change was 1, subjectively indicating great benefit when compared to before therapy. Quality of sleep also improved. Conclusions The SCI-PAS protocol reduced neuropathic pain in our subject. The mechanism behind the analgesic effect may involve the modulation of nociceptive and sensory neuronal circuits at the spinal cord level. The possibility to use PAS as an adjunct treatment in drug-resistant post-SCI neuropathic pain warrants further investigation and sham-controlled studies. Patients with neuropathic pain due to SCI may benefit from PAS therapy in addition to PAS therapy-induced improvement in motor function.

Objectives Changes in brain connectivity have been observed within the default mode network (DMN) in chronic low back pain (CLBP), however the extent of these disruptions and how they may be related to CLBP requires further examination. While studies using seed-based analysis have found disrupted functional connectivity in the medial prefrontal cortex (mPFC), a major hub of the DMN, limited studies have investigated other equally important hubs, such as the posterior cingulate cortex (PCC) in CLBP. Methods This preliminary study comprised 12 individuals with CLBP and 12 healthy controls who completed a resting-state functional magnetic resonance imaging (fMRI) scan. The mPFC and PCC were used as seeds to assess functional connectivity. Results Both groups displayed similar patterns of DMN connectivity, however group comparisons showed that CLBP group had reduced connectivity between the PCC and angular gyrus compared to healthy controls. An exploratory analysis examined whether the alterations observed in mPFC and PCC connectivity were related to pain catastrophizing in CLBP, but no significant associations were observed. Conclusions These results may suggest alterations in the PCC are apparent in CLBP, however, the impact and functional role of these disruptions require further investigation.