Volume 21, Issue 1

Objectives Repetitive transcranial magnetic stimulation (rTMS) of the primary motor cortex (M1) with frequencies 5–20 Hz is an expanding non-invasive treatment for chronic neuropathic pain (NP). Outcome data, however, show considerable inhomogeneity with concern to the levels of effect due to the great diversity of treated conditions. The aim of this review was to survey the literature regarding the efficacy and safety of M1 rTMS, and the accuracy to predict a positive response to epidural motor cortex stimulation (MCS) which is supposed to give a more longstanding pain relief. Methods A systematic literature search was conducted up to June 2019 in accordance with the PRISMA guidelines. We used the PICO Model to define two specific clinical questions: (1) Does rTMS of M1 relieve NP better than sham treatment? (2) Can the response to rTMS be used to predict the effect of epidural MCS? After article selection, data extraction, and study quality assessment, the certainty of evidence of treatment effect was defined using the GRADE system. Results Data on 5–20 Hz (high-frequency) rTMS vs. sham was extracted from 24 blinded randomised controlled trials which were of varying quality, investigated highly heterogeneous pain conditions, and used excessively variable stimulation parameters. The difference in pain relief between active and sham stimulation was statistically significant in 9 of 11 studies using single-session rTMS, and in 9 of 13 studies using multiple sessions. Baseline data could be extracted from 6 single and 12 multiple session trials with a weighted mean pain reduction induced by active rTMS, compared to baseline, of −19% for single sessions, −32% for multiple sessions with follow-up <30 days, and −24% for multiple sessions with follow-up ≥30 days after the last stimulation session. For single sessions the weighted mean difference in pain reduction between active rTMS and sham was 15 percentage points, for multiple sessions the difference was 22 percentage points for follow-ups <30 days, and 15 percentage points for follow-ups ≥30 days. Four studies reported data that could be used to evaluate the accuracy of rTMS to predict response to MCS, showing a specificity of 60–100%, and a positive predictive value of 75–100%. No serious adverse events were reported. Conclusions rTMS targeting M1 can result in significant reduction of chronic NP which, however, is transient and shows a great heterogeneity between studies; very low certainty of evidence for single sessions and low for multiple sessions. Multiple sessions of rTMS can maintain a more longstanding effect. rTMS seems to be a fairly good predictor of a positive response to epidural MCS and may be used to select patients for implantation of permanent epidural electrodes. More studies are needed to manifest the use of rTMS for this purpose. Pain relief outcomes in a longer perspective, and outcome variables other than pain reduction need to be addressed more consistently in future studies to consolidate the applicability of rTMS in routine clinical practice.

Objectives A significant proportion of adolescents with chronic musculoskeletal pain (CMP) experience difficulties in physical functioning, mood and social functioning, contributing to diminished quality of life. Generalized joint hypermobility (GJH) is a risk factor for developing CMP with a striking 35-48% of patients with CMP reporting GJH. In case GJH occurs with one or more musculoskeletal manifestations such as chronic pain, trauma, disturbed proprioception and joint instability, it is referred to as generalized hypermobility spectrum disorder (G-HSD). Similar characteristics have been reported in children and adolescents with the hypermobile Ehlers-Danlos Syndrome (hEDS). In the management of CMP, a biopsychosocial approach is recommended as several studies have confirmed the impact of psychosocial factors in the development and maintenance of CMP. The fear-avoidance model (FAM) is a cognitive-behavioural framework that describes the role of pain-related fear as a determinant of CMP-related disability. Content Pubmed was used to identify existing relevant literature focussing on chronic musculoskeletal pain, generalized joint hypermobility, pain-related fear and disability. Relevant articles were cross-referenced to identify articles possibly missed during the primary screening. In this paper the current state of scientific evidence is presented for each individual component of the FAM in hypermobile adolescents with and without CMP. Based on this overview, the FAM is proposed explaining a possible underlying mechanism in the relations between GJH, pain-related fear and disability. Summary and outlook It is assumed that GJH seems to make you more vulnerable for injury and experiencing more frequent musculoskeletal pain. But in addition, a vulnerability for heightened pain-related fear is proposed as an underlying mechanism explaining the relationship between GJH and disability. Further scientific confirmation of this applied FAM is warranted to further unravel the underlying mechanism. In explaining disability in individuals with G-HSD/hEDS, it is important to focus on both the physical components related to joint hypermobility, in tandem with the psychological components such as pain-related fear, catastrophizing thoughts and generalized anxiety.

Objectives During the current COVID-19 pandemic, healthcare has been transformed by the rapid switch from in person care to use of remote consulting, including video conferencing technology. Whilst much has been published on one-to-one video consultations, little literature exists on use of this technology to facilitate group interventions. Group pain management programmes are a core treatment provided by many pain services. This rapid review aimed to identify the extent of use of video conferencing technology for delivery of group pain management programmes and provide an overview of its use. Methods A rapid review of the literature published up to April 2020 (PubMed, PsycINFO and PEDro) was performed. The search string consisted of three domains: pain/CP (MeSH term) AND Peer group[MeSH] AND Videoconferencing[MeSH]/Telemedicine[MeSH]/Remote Consultation[MeSH]. The studies were of poor methodological quality and study design, and interventions and chronic pain conditions were varied. Results Literature searching yielded three eligible papers for this review. All studies had low methodological quality and risk of bias. Heterogeneity and variability in outcome reporting did not allow any pooling of data. The results demonstrated that videoconferencing for delivery of group programmes is possible, yet there is little extant literature on how to develop, deliver and measure outcomes of such programmes. Conclusions This review demonstrates that there is little evidence to support or guide the use of synchronous videoconferencing to deliver pain management programmes. We present issues to consider, informed by this review and our experience, when implementing video conferencing. Study quality of existing work is variable, and extensive future research is necessary.

Objectives Chronic pain patients often suffer in multiple locations. In health care, examinations of bodily pain usually do not include questions about temporomandibular disorders (TMD); hence TMD symptoms and potential comorbidities are not regularly assessed. Therefore, the primary aim was to evaluate the prevalence of TMD in patients referred to a pain rehabilitation clinic, and the secondary aim was to evaluate possible factors associated with TMD symptoms. Methods Consecutive chronic pain patients referred to the Pain Rehabilitation Clinic at the Umeå University Hospital in Sweden were included. TMD symptoms were assessed using three valid screening questions – 3Q/TMD. Pain sites, emotional distress, kinesiophobia, and demographics were obtained from the Swedish Quality Registry for Pain Rehabilitation. Results In total, 188 (144 women) chronic pain patients (mean age 41.8 years) were included. Of these, 123 (96 women) answered affirmatively to at least one of the 3Q/TMD. The relative risk of TMD symptoms among the patients with chronic pain, in comparison to the general population, was 7.1 (95% CI 5.9–8.4). Age was the only independent variable associated with TMD among the patients (p = 0.018). Conclusions The prevalence of TMD symptoms was higher in a chronic pain population compared to the general population. The 3Q/TMD questionnaire could be a suitable screening tool at pain rehabilitation clinics to identify patients for further examination of involvement of pain in the trigeminal region. Our results reinforce the clinical importance of paying attention to concurrent widespread pain and local TMD symptoms.

Objectives Multimodal rehabilitation programs (MMRPs) have been shown to be both cost-effective and an effective method for managing chronic pain in specialist care. However, while the vast majority of patients are treated in primary healthcare, MMRPs are rarely practiced in these settings. Limited time and resources for everyday activities alongside the complexity of chronic pain makes the management of chronic pain challenging in primary healthcare and the focus is on unimodal treatment. In order to increase the use of MMRPs incentives such as cost savings and improved health status in the patient group are needed. The aim of this study was to evaluate the cost-effectiveness of MMRPs for patients with chronic pain in primary healthcare in two Swedish regions. The aim of this study was to evaluate the cost-effectiveness of MMRPs at one-year follow-up in comparison with care as usual for patients with chronic pain in primary healthcare in two Swedish regions. Methods A cost-utility analysis was performed alongside a prospective cohort study comparing the MMRP with the alternative of continuing with care as usual. The health-related quality of life (HRQoL), using EQ5D, and working situation of 234 participants were assessed at baseline and one-year follow-up. The primary outcome was cost per quality-adjusted life year (QALY) gained while the secondary outcome was sickness absence. An extrapolation of costs was performed based on previous long-term studies in order to evaluate the effects of the MMRP over a five-year time period. Results The mean (SD) EQ5D index, which measures HRQoL, increased significantly (p<0.001) from 0.34 (0.32) to 0.44 (0.32) at one-year follow-up. Sickness absence decreased by 15%. The cost-utility analysis showed a cost per QALY gained of 18 704 € at one-year follow-up. Conclusions The results indicate that the MMRP significantly improves the HRQoL of the participants and is a cost-effective treatment for patients with chronic pain in primary healthcare when a newly suggested cost-effectiveness threshold of 19 734 € is implemented. The extrapolation indicates that considerable cost savings in terms of reduced loss of production and gained QALYs may be generated if the effects of the MMRP are maintained beyond one-year follow-up. The study demonstrates potential benefits of MMRPs in primary healthcare for both the patient with chronic pain and the society as a whole. The cost-effectiveness of MMRPs in primary healthcare has scarcely been studied and further long-term studies are needed in these settings.

Objectives In non-athletes, fear-avoidance and endurance-related pain responses appear to influence the development and maintenance of low back pain (LBP). The avoidance-endurance model (AEM) postulates three dysfunctional pain response patterns that are associated with poorer pain outcomes. Whether comparable relationships are present in athletes is currently unclear. This cross-sectional case-control study explored frequencies and behavioral validity of the AEM-based patterns in athletes with and without LBP, as well as their outcome-based validity in athletes with LBP. Methods Based on the Avoidance-Endurance Fast-Screen, 438 (57.1% female) young adult high-performance athletes with and 335 (45.4% female) without LBP were categorized as showing a “distress-endurance” (DER), “eustress-endurance” (EER), “fear-avoidance” (FAR) or “adaptive” (AR) pattern. Results Of the athletes with LBP, 9.8% were categorized as FAR, 20.1% as DER, 47.0% as EER, and 23.1% as AR; of the athletes without LBP, 10.4% were categorized as FAR, 14.3% as DER, 47.2% as EER, and 28.1% as AR. DER and EER reported more pronounced endurance- and less pronounced avoidance-related pain responses than FAR, and vice versa. DER further reported the highest training frequency. In athletes with LBP, all dysfunctional groups reported higher LBP intensity, with FAR and DER displaying higher disability scores than AR. Conclusions The results indicate that also in athletes, patterns of endurance- and fear-avoidance-related pain responses appear dysfunctional with respect to LBP. While EER occurred most often, DER seems most problematic. Implications Endurance-related pain responses that might be necessary during painful exercise should therefore be inspected carefully when shown in response to clinical pain.

Objectives Severe persistent post-surgical pain (PPSP) remains a significant healthcare problem. In the third most common surgical procedure in the U.K., groin hernia repair, including 85,000 surgeries, estimated 1,500–3,000 patients will annually develop severe PPSP. While the trajectory of PPSP is generally considered a continuation of the acute post-surgery pain, recent data suggest the condition may develop with a delayed onset. This study evaluated pain-trajectories in a consecutive cohort referred from groin hernia repair-surgeons to a tertiary PPSP-center. Potential explanatory variables based on individual psychometric, sensory, and surgical profiles were analyzed. Methods Patients completed graphs on pain trajectories and questionnaires on neuropathic pain, pain-related functional assessments, and psychometrics. Surgical records and quantitative sensory testing profiles were obtained. Pain trajectories were normalized, and pre- and post-surgical segments were analyzed by a normalized area-under-the-curve (AUC) technique. Principal component analysis (PCA) was applied to the explanatory variables. Significant PCA-components were further examined using multiple logistic regression models. Results In 95 patients, the AUC identified groups of post-surgical pain trajectories (p<0.0001): group I (n=48), acute high-intensity pain progressing to PPSP; group II (n=28), delayed onset of PPSP; group III (n=7), repeat-surgery gradually inducing PPSP. Data from groups IV (n=3) and V (n=9) were not included in the statistical analysis due to small sample size and data heterogeneity, respectively. The PCA/logistic analyses indicated that neuropathic pain scores, composite pain scores, and pain-related functional assessments were explanatory variables for groups I and II . Conclusions Pain trajectories in PPSP after groin hernia repair are heterogeneous but can be classified into meaningful groups. Examination of pain trajectories, mirroring the transition from acute to severe persistent post-surgical pain, has the potential of uncovering clinically relevant pathophysiological mechanisms.

Objectives Chronic non-malignant pain (CNP) is a significant healthcare problem with considerable consequences for patients, relatives and society. CNP is a lifelong condition that calls for acceptance and self-management. Existing research indicates that the involvement of relatives improves patients’ and relatives’ management of CNP, but the area is, at present, scarcely described. Research is required to obtain knowledge about the patients’ experiences, needs and preferences concerning the involvement of their relatives within the frame of CNP rehabilitation, which is the aim of this study. Methods The study applied a qualitative phenomenological-hermeneutic design conducting individual interviews with 10 patients with CNP from three selected Multidisciplinary Pain Centres (MPC). The analysis was guided by Paul Ricoeur’s philosophy of interpretation of the text. Results The findings illuminated the patients’ perspectives on the involvement of relatives within three key themes, each having two or three sub-themes. The analysis revealed that patients in CNP rehabilitation had various interpretations of the substance of involving relatives, reflecting their sparse experiences. It seemed arbitrary, who during the rehabilitation actually experienced the involvement of their relatives, leaving the impression of an area short of structure. This shortage was troublesome, due to a heartrending impact of CNP. Patients’ reduced functional level, combined with their surroundings difficulties in grasping the magnitude of CNP led to a loss of relationships and a risk of social isolation. Patients’ close relationships became essential but were under pressure as well. Patients living with a spouse/cohabitant experienced that the relationship was affected by a disrupted balance and pain-related emotional outbursts. The patients experienced a profound need for being understood, but the text also revealed a need for mutual understanding to acknowledge the relatives’ strain as well. Particular patients with children living at home experienced to be under great strain, complicated by a deep concern for long-term consequences for their children growing up influenced by parental CNP. Experienced involvement of relatives, even to a minor extend was perceived as beneficial for the patients, who experienced increased understanding and support from the relatives. However, due to the lack of a structured service, the patients’ access to the involvement of relatives became dependent on their ability to define their need and pick it out. Thus the patients also expressed a general preference for mandatory and structured involvement, yet tailored to the specific patient. Conclusions The study showed an overwhelming need for the involvement of relatives among patients with CNP, indicating that increased attention and investigation of relevant interventions are required. Despite differences between the MPC, our primary impression was that the involvement of relatives reached a minimal level of what was expected, which might entail desertion of patients scarce of resources. Individualised adjusted involvement of relatives is assumed to improve patient’s management of CNP in everyday life. A family systems nursing (FSN) approach is a relevant proposal for intervention, useful in other illness areas. Still, research needs to shed light on the appropriateness of FSN when involving relatives in the rehabilitation of CNP.

Objectives The association between socioeconomic status and recurrent abdominal pain (RAP) among adolescents is an understudied issue. No study has examined whether such an association changes over time. The aim was to examine trends in RAP among adolescents in Denmark from 1991 to 2018, to examine whether there was social inequality in RAP and whether this inequality varied over time. Methods The study used data from the Danish part of the international Health Behaviour in School-aged Children (HBSC) study of nationally representative samples of 11-, 13- and 15-year-olds. This study pooled data from eight comparable surveys from 1991 to 2018, overall participation rate 88.0%, n=30,048. The definition of RAP was self-reported stomach-ache daily or several days per week during the past six months. We reported absolute inequality as prevalence difference in RAP between low and high socioeconomic status and relative inequality as odds ratio for RAP by socioeconomic status. Results In the entire study population, 5.6% reported RAP, 3.1% among boys and 7.8% among girls. There was a significant increase in RAP from 1991 to 2018 among boys and girls, test for trend, p<0.0001. The prevalence of RAP was significantly higher in low than high socioeconomic status, OR=1.63 (95% CI: 1.42–1.87). The absolute social inequality in RAP fluctuated with no consistent increasing or decreasing pattern. Conclusions The prevalence of RAP increased from 1991 to 2018. The prevalence was significantly higher among girls than among boys, and significantly higher in low socioeconomic status families. Professionals should be aware of RAP as common and potentially serious health problems among children and adolescents. In addition to clinical examination it is important to focus on improving the child’s quality of life, reduce parents’ and children’s concerns about the seriousness of the condition, and consider supplements to medicine use.

Objectives Orebro Musculoskeletal Pain Screening Questionnaire (OMPSQ) is widely used in clinical practice and for research purpose to screen the risk of chronicity in patients with Non-specific low back pain (NSLBP). The questionnaire has been cross-culturally adapted into different languages, but to date, there has not been Hausa version of the questionnaire. This study is important as the Hausa language is widely spoken across sub-Saharan Africa. The study aims to cross-culturally translate the English version of the (OMPSQ) into Hausa language (OMPSQ-H) and to test its psychometric properties in Hausa patients with NSLBP. Methods This observational study involved the use of forward-backwards translation method for the English version of OMPSQ. Thus, 124 male and female participants with subacute NSLBP were recruited using convenient sampling techniques. The psychometric properties statistically tested included reliability, internal-consistency, ceiling and floor effects, acceptability and construct validity. Results The Hausa version of OMPSQ has demonstrated good reliability (ICC=0.82) and internal consistency (Cronbach’s alpha=0.72) with good acceptability as all questions were answered in 5 min. Responsiveness was adequate as OMPSQ-H retest scores demonstrated good correlation with the global rating of change scale scores ( r =0.67, p=0.01). Construct validity was evaluated using principal component analysis and it reveals six components structure for the OMPSQ-H. Conclusions The OMPSQ-H was successfully translated and cross-culturally adapted with no problem of comprehension. Moreover, it has shown adequate psychometric properties in terms of internal consistency, reliability, responsiveness and constructs validity. Consequently, the OMPSQ-H can be considered as a valid tool for identifying and screening both psychosocial risk factors and risk of chronicity of NSLBP in Hausa population.

Objectives Physical activity is essential for long-term chronic pain management, yet individuals struggle to participate. Exercise professionals, including fitness instructors, and personal trainers, are preferred delivery agents for education and instruction on chronic pain, physical activity, and strategies to use adherence-promoting behavioral skills. However, exercise professionals receive no relevant training during certification or continuing education opportunities to effectively support their participants living with chronic pain. Based on the ORBIT model for early pre-efficacy phases of development and testing of new behavioral treatments, the present Phase IIa proof-of-concept study was conducted. The purpose was to examine the impacts of a newly developed chronic pain and physical activity training workshop on psychosocial outcomes among exercise professionals. Outcomes included knowledge and attitudes regarding chronic pain, attitudes and beliefs about the relationship between pain and impairment, and self-efficacy to educate and instruct participants with chronic pain. Methods Forty-eight exercise professionals ( M age =44.4±11.0 years) participated in a three-hour, in-person workshop that was offered at one of four different locations. Participants completed pre- and post-workshop outcome assessment surveys. Results Mixed MANOVA results comparing time (pre- versus post-workshop) by workshop location (sites 1 to 4) illustrated a significant within-subjects time effect ( p <0.001). All outcomes significantly improved from pre- to post-workshop ( p ′s<0.001), demonstrating large effect sizes (partial eta-squared values ranging from 0.45 to 0.59). Conclusions Findings offer early phase preliminary support for the effectiveness of the chronic pain and physical activity training workshop for exercise professionals. Based on ORBIT model recommendations, findings warrant future phased testing via a pilot randomized clinical trial as well as testing for impacts that trained professionals have on activity adherence among their clients living with chronic pain. Eventual workshop adoption by exercise professional certification organizations would ensure widespread and sustainable access to qualified exercise professionals to help individuals engage in physical activity. By increasing the capacity of available exercise professionals to deliver effective support, active individuals could better manage their chronic pain and live well.

Objectives Severe post-operative pain is common after total knee arthroplasty. Patient-controlled analgesia is an alternative method of pain management, whereby a patient administers his or her own pain medication. Patients seem to prefer this method over nurse-administered analgesia. However, it remains unclear whether patients using patient-controlled analgesia devices use higher or lower doses of opioids compared to patients treated with oral opioids. Methods This retrospective study examined 164 patients undergoing total knee arthroplasty. Post-operatively, 82 patients received oxycodone via intravenous patient-controlled analgesia devices, while the pain medication for 82 patients in the control group was administered by nurses. The main outcome measure was the consumption of intravenous opioid equivalents within 24 h after surgery. Secondary outcome measures were the use of anti-emetic drugs and the length of stay. Furthermore, we evaluated opioid-related adverse event reports. Results The consumption of opioids during the first 24 h after surgery and the use of anti-emetic drugs were similar in both groups. The median opioid dose of intravenous morphine equivalents was 41.1 mg (interquartile range (IQR): 29.5–69.1 mg) in the patient-controlled analgesia group and 40.5 mg (IQR: 32.4–48.6 mg) in the control group, respectively. The median length of stay was 2 days (IQR: 2–3 days) in the patient-controlled analgesia group and 3 days (IQR: 2–3 days) in the control group (p=0.02). The use of anti-emetic drugs was similar in both groups. Conclusions The administration of oxycodone via intravenous patient-controlled analgesia devices does not lead to increased opioid or anti-emetic consumptions compared to nurse-administered pain medication after total knee arthroplasty. Patient-controlled analgesia might lead to shortened length of stay.

Objectives The prevalence and impact of pain among patients with multiple myeloma (MM) in their everyday life require renewed attention. MM patients’ survival has increased considerably over the last decades and active disease episodes are interrupted by longer periods with disease inactivity. The aim with this study is to explore pain intensity and pain interference with daily activities during periods of stable or inactive MM disease. Methods In a cross-sectional study from September 2017 to May 2019, self-reliant MM patients in stable disease filled a comprehensive selection of validated questionnaires regarding pain, other symptoms and quality of life, which they experienced in their daily living. Patient reported pain intensity and interference with daily activities were analyzed for associations with several clinical and demographic factors and discussed from a total pain perspective. The two outcomes, pain intensity and pain interfering with daily activities, were analyzed in two age groups (<65 years or ≥65 years). Results Among 92 participants, 80% experienced pain to interfere with their daily activities (equal in both age groups), and 63% reported moderate to severe pain intensity; (75% ≥65 years, and 49% <65 years). Pain intensity was significantly associated with signs of depression (OR 4.0 [95% CI: 1.2–13.9]) and age ≥65 years (OR 3.3 [95% CI: 1.2–9.2]). Pain interfering with daily activities was nearly significantly associated with bone involvement (OR 3.4 [95% CI: 1.0–11.6]) and signs of depression (OR 5.9 [95% CI: 1.0–36.3]). The patients were bothered with many problems in addition to pain; fatigue (91%), bone involvement (74%), signs of depression (41%), signs of anxiety (32%), comorbidity (29%) and uncertainty in relation to employment or pension (25%). Neuropathic pain was more prevalent in the feet (33% [95% CI: 23%, 43%]) compared with pain in the hands (13% [95% CI: 7%, 22%]). Conclusions In periods of stable disease, many MM patients continue to live with intense pain interfering with their daily activities. Additional or associated problems are the presence of bone involvement, neuropathic pain, older age, uncertainty in relation to employment or pension, comorbidity, signs of depression, anxiety and fatigue. This highlights the importance of health professionals being receptive to the patients’ experience of pain throughout their trajectories, to assess pain systematically and to interpret this experience from a total pain perspective. While pain problems in relation to diagnosing and treating MM is well known, this study brings the message that even during periods of stable or inactive MM disease, the patients experience pain with a moderate to severe intensity, that interferes with their everyday living. The improved survival and the consequential long trajectories make coherence in the pain treatment even more important for the patients, who may see different professionals in different health care settings for different reasons. The patient group requires a coordinated, holistic patient-centered pain treatment throughout the disease trajectory.

Objectives Several clinical and experimental studies reported the anxiety as one of the neuropathic pain comorbidities; however, the mechanisms involved in this comorbidity are incompletely cleared. The current study investigated the consequence of pain induced by peripheral neuropathy on the serotonin (5-HT) level of the CA1 region of the hippocampus, which is known as a potential reason, for anxiety associated with neuropathic pain. Methods In this manner, 72 male rats were inconstantly subdivided into three experimental groups as follows: control, sham, and chronic constriction injury (CCI). Neuropathic pain was initiated by the CCI of the sciatic nerve, and then, mechanical allodynia, thermal hyperalgesia, and anxiety-like behavior were evaluated using the von Frey filaments, radiant heat, open field test (OFT), and elevated plus maze (EPM) respectively. To investigate the probable mechanisms, the in vivo extracellular levels of 5-HT were assessed by microdialysis and using reverse-phase high-pressure liquid chromatography (HPLC) in the CA1 region of hippocampus on days 16 and 30 post-CCI. Results Our data suggested that CCI caused anxiety-like behavior in OFT and EPM test. 5-HT concentration in the CA1 region of the hippocampus significantly (F=43.8, p=0.000) reduced in CCI rats, when the pain threshold was minimum. Nevertheless, these alterations reversed while the pain threshold innate increased. Conclusions Neuropathic pain, initiated by constriction of the sciatic nerve can induce anxiety-like behavior in rats. This effect accompanies the reduction in 5-HT concentration in the CA1 region of the hippocampus. When the pain spontaneously alleviated, 5-HT level increased and anxiety-like behavior relieved.

Objectives Physical activity can lead to hypoalgesic effects and is often recommended as part of multidisciplinary pain management. Based on the idea, that in future specific and more differentiated sports therapeutic interventions could be used for a multidisciplinary pain management, various type of sports and their effects on pain sensitivity should be analysed. Whereas endurance as well as strengthening exercises are associated with a decrease in pain sensitivity in healthy people as well as people with chronic pain states, the effects of a specific coordination training (CT) on pain sensitivity have not yet been sufficiently investigated. Therefore, aim of the present study was to examine if a single bout of CT leads to exercised-induced hypoalgesia in young healthy men. Methods Thirty five healthy men (mean age 27 ± 3 years) were examined in a randomised crossover design before and after a single bout of 45-min CT and a 45-min resting session as control condition by means of Quantitative Sensory Testing (QST). The QST is a validated instrument to assess the function of the somatosensory system, by applying thermal and mechanical stimuli. By doing so, various detection and pain thresholds were determined at the dorsum of one foot. Exercises of CT were chosen to generate high proprioceptive input for the ankle joints. Results Analysis of the QST data in respect of the factors group (CT/control condition), time (pre/post) and stimuli (parameter of QST) revealed no statistically significant main effects of a single bout of CT on somatosensory system, neither for the factors group*time (p=0.51), nor the factors group*time*stimuli (p=0.32). All stimuli remained constant in the course of both conditions (e.g. mean ± sd of heat pain threshold pre/post in °C: coordination: 44.7 ± 3.1/44.8 ± 2.9; rest: 45.5 ± 3.0/44.9 ± 3.0). Conclusions In this setting, a single bout of CT had no effect on the somatosensory system in young healthy men. Therefore, this specific CT did not lead to an exercised-induced hypoalgesia in healthy people. Intensity of sensory input during training intervention might be too low to generate analgesic effects in a non-pathological altered somatosensory system of young healthy men. Further research is needed to clarify if a CT can induce exercised-induced hypoalgesia in people with pathological alterations of the somatosensory system. In addition, it has to examined if analgesic effects can be induced by changing the intensity of CT in healthy people. Detailed knowledge regarding the effects of different training interventions on pain modulation is needed to completely understand the mechanism of exercised-induced hypoalgesia.

Objectives In evidence-based medicine, we base our conclusions on the effectiveness of interventions on the results of high-quality meta-analysis. If a new randomized controlled trial (RCT) is unlikely to change the pooled effect estimate, conducting the new trial is a waste of resources. We evaluated whether recommendations not to conduct further RCTs reduced the number of trials registered for two scenarios. Methods Analysis of registered trials on the World Health Organisation (WHO) International Clinical Trials Registry Platform (ICTRP). We regarded trial protocols relevant if they evaluated the effectiveness of (1) exercise for chronic low back pain (LBP) and (2) cognitive behavioural therapy (CBT) for chronic pain. We calculated absolute and relative numbers and change of registered trials in a pre-set time window before and after publication of the recommendations, both published in 2012. Results We found 1,574 trials registered in the WHO trial registry for exercise in LBP (459 before 2012; 1,115 after) and 5,037 trials on chronic pain (1,564 before 2012; 3,473 after). Before 2012, 13 trials on exercise for LBP (out of 459) fit the selection criteria, compared to 42 trials (out of 1,115) after, which represents a relative increase of 33%. Twelve trials (out of 1,564) regarding CBT for chronic pain, fit the selection criteria before 2012 and 18 trials (out of 3,473) after, representing a relative decrease of 32%. We found that visibility, media exposure and strength of the recommendation were related to a decrease in registered trials. Conclusions Recommendations not to conduct further RCTs might reduce the number of trials registered if these recommendations are strongly worded and combined with social media attention.

Objectives The underlying mechanisms for individual differences in experimental pain are not fully understood, but genetic susceptibility is hypothesized to explain some of these differences. In the present study we focus on three genetic variants important for modulating experimental pain related to serotonin (SLC6A4 5-HTTLPR/rs25531 A>G), catecholamine (COMT rs4680 Val158Met) and opioid (OPRM1 rs1799971 A118G) signaling. We aimed to investigate associations between each of the selected genetic variants and individual differences in experimental pain. Methods In total 356 subjects (232 low back pain patients and 124 healthy volunteers) were genotyped and assessed with tests of heat pain threshold, pressure pain thresholds, heat pain tolerance, conditioned pain modulation (CPM), offset analgesia, temporal summation and secondary hyperalgesia. Low back pain patients and healthy volunteers did not differ in regards to experimental test results or allelic frequencies, and were therefore analyzed as one group. The associations were tested using analysis of variance and the Kruskal-Wallis test. Results No significant associations were observed between the genetic variants (SLC6A4 5-HTTLPR/rs25531 A>G, COMT rs4680 Val158Met and OPRM1 rs1799971 A118G) and individual differences in experimental pain (heat pain threshold, pressure pain threshold, heat pain tolerance, CPM, offset analgesia, temporal summation and secondary hyperalgesia). Conclusions The selected pain-associated genetic variants were not associated with individual differences in experimental pain. Genetic variants well known for playing central roles in pain perception failed to explain individual differences in experimental pain in 356 subjects. The finding is an important contribution to the literature, which often consists of studies with lower sample size and one or few experimental pain assessments.

Objectives The decoding of facial expressions of pain plays a crucial role in pain diagnostic and clinical decision making. For decoding studies, it is necessary to present facial expressions of pain in a flexible and controllable fashion. Computer models (avatars) of human facial expressions of pain allow for systematically manipulating specific facial features. The aim of the present study was to investigate whether avatars can show realistic facial expressions of pain and how the sex of the avatars influence the decoding of pain by human observers. Methods For that purpose, 40 female (mean age: 23.9 years) and 40 male (mean age: 24.6 years) observers watched 80 short videos showing computer-generated avatars, who presented the five clusters of facial expressions of pain (four active and one stoic cluster) identified by Kunz and Lautenbacher (2014). After each clip, observers were asked to provide ratings for the intensity of pain the avatars seem to experience and the certainty of judgement, i.e. if the shown expression truly represents pain. Results Results show that three of the four active facial clusters were similarly accepted as valid expressions of pain by the observers whereas only one cluster (“raised eyebrows”) was disregarded. The sex of the observed avatars influenced the decoding of pain as indicated by increased intensity and elevated certainty ratings for female avatars. Conclusions The assumption of different valid facial expressions of pain could be corroborated in avatars, which contradicts the idea of only one uniform pain face. The observers’ rating of the avatars’ pain was influenced by the avatars’ sex, which resembles known observer biases for humans. The use of avatars appeared to be a suitable method in research on the decoding of the facial expression of pain, mirroring closely the known forms of human facial expressions.

Objectives Burning mouth syndrome (BMS) is a long-lasting pain condition which is commonly associated with anxiety symptoms and experience of adverse, stressful life events have been reported by those diagnosed with the syndrome. Stress-related biomarkers have been related to personality traits in BMS and a personality with high stress susceptibility and perceived stress may be of importance. Although biopsychosocial approaches are suggested to manage long-lasting orofacial pain, to date little is known about physical activity in women with BMS. The aim of this study was to investigate if personality, perceived stress and physical activity distinguish women with BMS from controls. Methods Fifty-six women with BMS and 56 controls matched on age and gender completed Swedish universities Scales of Personality (SSP), Perceived Stress Questionnaire (PSQ) and a general questionnaire with an item on weekly physical activity frequency. In addition, health-related quality of life was explored by additional questionnaires and reported in a companion article (Jedel et al. Scand J Pain. 2020. PubMed PMID: 32853174). Results SSP subscales Somatic Trait Anxiety, Psychic Trait Anxiety, Stress Susceptibility and Verbal Trait Aggression differed between women with BMS and controls and the personality factor scores for Neuroticism and Aggressiveness were higher. Perceived stress measured by PSQ index was higher for women with BMS compared to controls. Women with BMS reported lower physical activity frequency compared to controls and those reporting physical activity <4 days/week scored higher on PSQ compared to those with weekly physical activity ≥4 days/week. Conclusions Personality distinguished women with BMS from controls in this study. Perceived stress was higher and weekly physical activity was lower in women with BMS compared to controls. Our findings suggest physical activity should be more comprehensively measured in future BMS studies and, by extension, physical activity may be a treatment option for women with BMS. Pain management aiming to restore function and mobility with stress reduction should be considered in clinical decision making for women with BMS who have a personality with stress susceptibility, especially if reporting high perceived stress and insufficient physical activity.

Objective To highlight an extremely unusual presentation of an aggressive, rare small bowel malignancy presenting as abdominal myofascial pain syndrome. Case presentation The report is presented from a tertiary pain medicine unit at a university teaching hospital. A female patient presenting with chronic abdominal pain was initially diagnosed as abdominal myofascial pain syndrome. The report details the possible facilitation of the diagnosis of a rare, highly aggressive small bowel tumour by interventional treatment for abdominal myofascial pain syndrome. Conclusion This case highlights a rare and aggressive malignancy of the small intestine presenting clinically as abdominal myofascial pain syndrome.

Objectives Nerve injury may lead to pain and sensory changes such as dysesthesia and paresthesia. Quantitative sensory testing (QST) is a psychophysical testing method used to quantify nerve damage and monitor its recovery. Duloxetine is used in the management of neuropathic pain conditions, but its effect on taste recovery has not been previously reported. Case representation A 65-year-old female, presented to the orofacial pain clinic, with a chief complaint of a burning sensation on the tongue, taste changes and a feeling of tightness beneath the tongue for five months. She reported that the complaints began subsequent to a complicated dental extraction during which she experienced trauma to the tongue. Patient was advised to take duloxetine 60 mg in divided doses three times daily. The assessment and monitoring of the recovery pattern were performed using QST. Electrical taste detection (mediated by chorda tympani) and electrical detection/tingling thresholds were performed at periodic intervals for up to a year following the nerve injury in the chorda tympani and lingual nerve territory. The patient reported complete recovery in taste sensation with duloxetine and this correlated with the QST results. QST documented at the end of one year revealed the electrical taste detection threshold and electrical detection threshold return to near normal values. Conclusions QST may be a useful diagnostic tool to assess and monitor lingual and chorda tympani nerve injuries. Duloxetine may aid in the recovery of the taste changes following lingual and chorda tympani nerve injury.

Objectives The purpose of this case report is to describe an occurrence of a rare complication of lead extrusion, which was observed 10 months after spinal cord stimulator (SCS) implantation. Methods A patient with low back pain and failed back surgery syndrome underwent implantation of a SCS without complications. Ten months after implantation, one SCS lead extruded from her lower back leading to surgical removal of the leads. Results After identifying the complication of a SCS lead extruding from the patient’s back, a surgical revision was performed to remove the SCS leads but retain the implantable pulse generator (IPG) in the gluteal region. During the surgery, it was noted that the anchors were in the appropriate position, sutured and fibrosed to a deep fascial layer. There were no complications from the surgical revision and no infectious process was observed. Conclusions We report the occurrence and management of a rare complication of SCS lead extrusion after SCS implantation for failed back surgery syndrome. After recognition, removal of the leads with retention of the IPG was able to effectively resolve the complication. The revising procedure was well tolerated but resulted in the recurrence of the patient’s previous low back pain. We believe that knowledge of this case and its management will aid future physicians in the recognition and management of this rare complication of SCS implantation. Furthermore, as there is a paucity of literature discussing the management of lead extrusion after SCS implantation, we hope that this case report will spur additional research on the management of this complication.

Objectives Opioids are the most potent analgesics in the treatment of postoperative pain. Respiratory depression is, however, a serious side effect. The aims of this study were to evaluate current practice and routines for post-operative administration of opioids in a Norwegian university hospital and to evaluate whether the clinical safeguards adequately protected patients’ safety regarding risk of respiratory depression. Methods The study had a retrospective cross-sectional design and included 200 patients, treated with opioids postoperatively. The patients were treated in a post-anesthesia care unit (PACU) before transferal to a surgical ward. Relevant data such as opioid dosages, routes of administration, sedation and respiratory function, routines for patient monitoring, and numbers of patients with opioid induced respiratory depression was collected. Results Two patients (1%) developed respiratory depression that needed naloxone to reverse the effect, and 32 patients (16%) had a respiratory rate (RR) <10/min, which may have been caused by opioids. In the PACU, the patient’s RR was evaluated on a routine base, but after transferal to a surgical ward RR documented in only 7% of the patients. Conclusions The lack of routines for patient monitoring, especially RR, represented a risk of not detecting opioid induced respiratory depression.