Volume 21, Issue 2

Objectives Experimental pain is a commonly used method to draw conclusions about the motor response to clinical musculoskeletal pain. A systematic review was performed to determine if current models of acute experimental pain validly replicate the clinical experience of appendicular musculoskeletal pain with respect to the distribution and quality of pain and the pain response to provocation testing. Methods A structured search of Medline, Scopus and Embase databases was conducted from database inception to August 2020 using the following key terms: “experimental muscle pain” OR “experimental pain” OR “pain induced” OR “induced pain” OR “muscle hyperalgesia“ OR (“Pain model” AND “muscle”). Studies in English were included if investigators induced experimental musculoskeletal pain into a limb (including the sacroiliac joint) in humans, and if they measured and reported the distribution of pain, quality of pain or response to a provocation manoeuvre performed passively or actively. Studies were excluded if they involved prolonged or delayed experimental pain, if temporomandibular, orofacial, lumbar, thoracic or cervical spine pain were investigated, if a full text of the study was not available or if they were systematic reviews. Two investigators independently screened each title and abstract and each full text paper to determine inclusion in the review. Disagreements were resolved by consensus with a third investigator. Results Data from 57 experimental pain studies were included in this review. Forty-six of these studies reported pain distribution, 41 reported pain quality and six detailed the pain response to provocation testing. Hypertonic saline injection was the most common mechanism used to induce pain with 43 studies employing this method. The next most common methods were capsaicin injection (5 studies) and electrical stimulation, injection of acidic solution and ischaemia with three studies each. The distribution of experimental pain was similar to the area of pain reported in clinical appendicular musculoskeletal conditions. The quality of appendicular musculoskeletal pain was not replicated with the affective component of the McGill Pain Questionnaire consistently lower than that typically reported by musculoskeletal pain patients. The response to provocation testing was rarely investigated following experimental pain induction. Based on the limited available data, the increase in pain experienced in clinical populations during provocative maneuvers was not consistently replicated. Conclusions Current acute experimental pain models replicate the distribution but not the quality of chronic clinical appendicular musculoskeletal pain. Limited evidence also indicates that experimentally induced acute pain does not consistently increase with tests known to provoke pain in patients with appendicular musculoskeletal pain. The results of this review question the validity of conclusions drawn from acute experimental pain studies regarding changes in muscle behaviour in response to pain in the clinical setting.

Background Surgery may possibly be undermined by psychologic, psychiatric and psychosomatic problems, as long as these problems interfere with a patient’s capacity to cope with surgery adaptively. Recent studies have shown that interpersonal trauma, e.g. abuse or neglect, and its correlates are involved in the adaptation to surgery. This observation is heuristically coherent, given the respective traumatization is an interpersonal event occurring in a relationship. Notably, surgery inevitably leads to the violation of physical boundaries within a doctor-patient relationship. Based on the principles of psycho-traumatologic thinking, such a constellation is deemed qualified to activate posttraumatic symptoms in the traumatized. Method The present topical review summarizes the respective findings which point to a subgroup of patients undergoing surgery, in whom difficulty bearing tension and confiding in others may cause adaptive problems relevant to surgery. Although this theorizing is empirically substantiated primarily with respect to total knee arthroplasty (TKA), a pubmed-research reveals psychopathologic distress to occur prior to surgery beyond TKA. Likewise, posttraumatic distress occurs in large numbers in the context of several operations, including cardiac, cancer and hernia surgery. Conclusion Aspects of psychological trauma may be linked to the outcomes of general surgery, as well, e.g. biliary, hernia or appendix surgery. The mechanisms possibly involved in this process are outlined in terms of a hierarchical organization of specific anxiety and negative affect as well as in terms of psychodynamics which imply the unconscious action of psychologic defenses at their core. Implications Not least, we encourage the screening for trauma and its correlates including defenses prior to general surgery in order to identify surgical candidates at risk of, e.g. chronic postoperative pain, before the operation.

Objectives Fear-avoidance beliefs questionnaire (FABQ) is a self-report, valid and reliable questionnaire to quantify fear and avoidance beliefs related to physical activity and work. Furthermore, it can be used to predict prolong disability in patients with non-specific neck pain. Although it was originally developed to manage patients with low back pain, it has also been studied in individuals with neck pain. This questionnaire was translated into several languages following reports of potential benefits in patients with neck pain. Recently, Thai neck clinical trials, international multi-centre trials and data sharing are growing throughout the world but no validated Thai version of the FABQ is available for clinical and research uses. Our objectives were to translate and cross-culturally adapt the FABQ into Thai version and evaluate its psychometric properties in Thai patients with non-specific neck pain. Methods Cross-cultural translation and adaptation of the FABQ were conducted according to standard guidelines. A total of 129 participants with non-specific neck pain were invited to complete the Thai versions of the FABQ (FABQ-TH), neck disability index and visual analogue scale for pain intensity. Psychometric evaluation included exploratory factor analysis, internal consistency, test-retest reliability, agreement, and convergent validity. Thirty participants completed the FABQ-TH twice with a 48-h interval between tests to assess the test-retest reliability. Results Factor analysis identified four components for the FABQ-TH (66.69% of the total variance). The intraclass correlation coefficient of test-retest reliability was excellent for the total score (0.986), work attitudes (0.995), physical activity attitudes (0.958), physical activity experiences (0.927), and expected recovery (0.984). Cronbach’s alpha for internal consistency was excellent (range 0.87–0.88) for all items. The minimal detectable change of the FABQ-TH was 5.85. The FABQ-TH correlated to its subscales (range 0.470–0.936), indicating the strongest association with work attitude. The weakest correlation was observed between the FABQ-TH and disability ( r s =0.206, p=0.01). Missing data and significant floor or ceiling effects were not found. Conclusions The Thai version of the FABQ for non-specific neck pain was successfully adapted. It is a valid and reliable instrument to quantify fear and avoidance beliefs among patients with non-specific neck pain who speak and read Thai.

Objectives Patients with head and neck cancer (HNC) experience serious pain related to tumour, surgery, chemotherapy, and radiotherapy treatment (RT). Oral mucositis, a painful complication of RT, may require opioid analgesics to control pain.This longitudinal study, during RT but also four weeks post-RT, examines the relationships between oral mucositis, pain, and opioid doses in in HNC patients. The aim was to evaluate the clinical effectiveness of an opioid treatment strategy. Methods Sixty-three patients with HNC undergoing radiotherapy answered self-reported questionnaires on pain intensity on a 0–10 numerical rating scale (NRS) three times a week. Oral mucositis signs were evaluated using the WHO mucositis index score, ranging from 0 (normal) to 4 (severe), and pharmacological treatment with opioids was registered prospectively once a week. All data were related to given radiation dose, and all outcome measures at each time point therefore relate to the same radiation dose (i.e., not to when the patient was included in the study). Results Opioids were used by 78% of the patients. Most of the patients experienced only mild pain (NRS 0–4), although the majority developed mucositis grade 2–4 according to WHO mucositis index. Function-related pain intensity and opioid doses were highest during the sixth week of RT, with 3.67 (0–9) in NRS and 84 (0–430) mg oral morphine equivalents per day (median, range). At that same time point, significant positive correlations were found between the grade of mucositis and pain intensities. Patients with mucositis grade 2–4 were investigated further; in this subgroup, we found that opioid doses did not differ between patients with mild pain and patients with moderate to severe pain. Our multivariate data analysis defined a cluster of patients characterized by the presence of mucositis, cancer site in pharynx, concomitant chemotherapy, and the absence of surgery. Conclusions In HNC patients who were followed closely by pain care personnel during and after RT, pain was often satisfactorily alleviated with a structured use of opioids, including stepwise increases of fentanyl patches and oral morphine as needed. However, some patients with oral mucositis grade 2–4 experienced severe pain. Strong opioids, i.e. the third step of the WHO pain ladder, remain the mainstay of analgesic therapy in treating moderate to severe cancer-related pain, including patients with HNC. This real-life study indicates that RT-related pain is not a fatality. A proactive stance, monitoring these patients closely and regularly, is probably crucial in order to achieve good treatment results. Further studies are needed to develop better pain treatment strategies for those patients who develop severe oral mucositis-related pain despite intensive opioid treatment.

Objectives It is important to validate self-reported musculoskeletal pain used in epidemiological studies for evaluation of pain outcome measures. The main objective of this paper was to assess the association between self-reported neck/shoulder/upper limb pain and clinical signs of disorders in the region, especially by comparing a measure that only used pain intensity with a measure that combined pain intensity and pain duration. Methods Four hundred and twenty technical school students of both genders were included with a median age of 17 years (16–28). The students stated the pain in four intensity grades and the pain duration in four period lengths within the preceding four weeks period. A pain severity index was calculated by multiplying the pain intensity (0–3) and the duration (1–4). A clinical examination was performed within a week after completing the form. The associations were evaluated by agreement, correlation and symmetric strength of association (contingency). Results The study found low correlation and low positive agreement for neck/shoulder and upper limb pain related to clinical signs of disorders in the region. However, the relationship showed high negative agreement and high contingency. The negative agreement increased for the neck/shoulder region with higher cut-off points for dichotomization, but not for the upper limb region. The index combining reports of pain intensity with pain duration, do not improve agreement, correlation or contingency with clinical signs compared to use of pain intensity alone. Conclusions This study showed an association between self-reported neck/shoulder/upper limb pain intensity and clinical signs of musculoskeletal disorders of the region. An index combining pain intensity and duration (Pain Severity Index) did not increase this association. From the results we suggest using pain intensity reports alone and if dichotomizing is wanted, choosing a cut-off point at high pain levels, especially for neck and shoulder pain.

Objectives Chronic, clinical pain states are often accompanied by distress such as anxiety and depression. The aim of this study was to determine if certain clinical pain variables could predict the level of anxiety and depression in subjects with musculoskeletal pain. Methods Two multiple linear regression analyses were conducted on a sample consisting of 189 subjects with clinical pain with the independent pain variables of pain intensity, the influence of pain on daily activities, pain persistence, pain duration, and the number of pain locations. The dependent variables measured anxiety and depression, respectively. Result Two statistically significant models were found, where the predicted variables accounted for 37.0% of the variability in the anxiety levels and 43.7% of the variability in the depression levels. The independent variable, the influence of pain on daily activities, significantly predicted the level of anxiety. The variables, the influence of pain on daily activities and the number of pain locations, significantly predicted the levels of anxiety and depression. Conclusions This study showed that two different independent variables, the influence of pain on daily activities and the number of pain locations, significantly predicted the levels of depression. The predictor, the influence of pain on daily activities, significantly predicted the levels of anxiety. The knowledge gained about which specific pain variables are more likely to coexist with anxiety and depression in clinical pain states could be important in implementing holistic treatment plans for chronic pain.

Objectives Musculoskeletal (MSK) pain is a common complaint in patients with inflammatory bowel diseases (IBD). MSK pain in IBD has previously demonstrated association with symptoms of central sensitization; however it is uncertain whether these symptoms are influenced simply by the presence of MSK pain and/or IBD. Primary aim of this study was to investigate whether symptoms of central sensitization differed across three groups: IBD patients with and without MSK pain and healthy controls. Secondary aim was to investigate between-group differences for measures of somatosensory functioning. Methods Cross-sectional study was performed on adults with IBD. Assessments included: central sensitization inventory (CSI), pressure pain threshold, temporal summation, conditioned pain modulation, perceived stress, affect style, anxiety, depression, and pain catastrophizing. One-way analyses of variance and covariance were used to investigate between-group differences for measures of central sensitization and potential confounding by psychological factors. Results Study participants (n = 66) were age/gender matched across three study groups. Between-group differences were solely demonstrated for CSI scores [ F (2,63)=19.835, p<0.001, r=0.62], with IBD patients with MSK pain demonstrating the highest CSI scores and healthy controls the lowest. After controlling for individual psychological features, post hoc comparisons indicated that CSI scores were significantly different between-groups (p≤0.025) after controlling for most psychological variables, with the exception of perceived stress (p=0.063) and pain catastrophizing (p=0.593). Conclusions IBD patients as a whole demonstrated significantly greater symptoms of central sensitization compared to healthy controls. However, IBD patients with persistent MSK pain demonstrated the greatest symptoms of central sensitization compared to patients without MSK pain and healthy controls. Between-group differences for CSI in IBD patients with MSK were not confounded by psychological features. Implications Study results indicate that persistent MSK pain in IBD represents patients with greater central sensitization symptomology. This increased symptomology is suggestive of underlying mechanisms related to central sensitization, highlighting patient potentially at risk for worse pain experiences.

Objectives Chronic neuropathic pain is common in people living with HIV. Psychological treatments can improve quality of life for people with chronic pain in general, and online delivery can increase access to these treatments. However, the acceptability of psychological treatment and online delivery have not been investigated in-depth in people living with HIV and chronic neuropathic pain. Therefore, a qualitative study was undertaken to explore views about a psychological treatment for pain management in this population and to investigate the acceptability of online treatment delivery. Methods Qualitative interviews were conducted and analysed using inductive thematic analysis, adopting a critical realist perspective. Twenty-six people living with HIV and chronic neuropathic pain completed semi-structured interviews. Their views about a psychological treatment for pain management and online delivery were explored in-depth. Results Three themes and 12 subthemes were identified. Theme one represents a desire for a broader approach to pain management, including not wanting to take more pills and having multidimensional goals that were not just focussed on pain relief. Theme two includes barriers to online psychologically-based pain management, including concerns about using the Internet and confidentiality. Theme three describes treatment facilitators, including accessibility, therapist support, social connection, and experiencing success. Conclusions A psychological treatment for chronic neuropathic pain management appears acceptable for people living with HIV. Therapist-supported online delivery of cognitive-behavioural pain management may be acceptable for people living with HIV given appropriate development of the treatment to address identified barriers to engagement. These data can inform developments to enhance engagement in online psychologically-informed pain management in people living with HIV and more broadly in remote delivery of psychological treatments.

Objectives Dance teachers are strongly dependent on their functional body in their professional practice. As yet, it has largely been unclear whether the musculoskeletal system is endangered by a dance teaching activity. Pain can be a warning signal for a health hazard. The aims of the study were (a) to determine the pain prevalence, location and assessment of dance teachers and (b) to identify determinants of pain occurrence over a 3-month period prior to the survey. Methods The quantitative, retrospective cohort study was conducted with n=166 dance teachers by an anonymous online survey. The data on the study sample, professional practice and pain prevalence, location and assessment were presented descriptively. A binary logistic regression was used to identify determinants of pain occurrence in the last 3 months from the sample parameters and the data of professional practice. Results In the 3-month period n=143 (86.1%) of dance teachers had been in pain, often localized in the lower back and lower extremities. In the binary logistic regression model, the Body mass index (BMI) (odds ratio (OR)=1.15, 95% CI: 0.93–1.42, p=0.18), age (OR=1.03, 95% CI: 0.99–1.08, p=0.11) and the presence of disease (OR=2.81, 95% CI: 0.78–10.15, p=0.12) were identified as determinants of pain occurrence (LR-Chi 2 =7.8, p<0.05, pseudo R 2 =0.06, n=160). Conclusions Pain occurs in dance teachers under multifactorial conditions. Pain occurrence seems to be favored by context factors, such as the BMI, age and the presence of diseases. However, none of these factors could be identified as a significant, clear risk factor for the occurrence of pain in this sample. Education and preventive measures, that consider pain as a warning signal, should take effect early in the dance career.

Objectives Somatosensory amplification (SA) has been described as an important feature of somatoform disorders, and an “amplifying somatic style” has been reported as a negative connotation of body perception. As widespread pain (WSP) in fibromyalgia (FM) is due to a central sensitization (CS) rather than organic alterations, there has been discussion as to whether FM is equivalent to or distinct from somatization disorder (SD). Assuming SD and FM are two distinct entities, an increase in somatic amplification should be expected only in subjects who have SD, regardless of the type of pain they experience. Purpose of the study was to explore the magnitude of SA in FM, and whether this depends on the association with SD. Methods FM (n=159) other forms of chronic pain (OCP, n=582), psychiatric (Psy, n=53) and healthy (H, n=55) subjects were investigated using the Somatosensory Amplification Scale (SSAS), Illness Behavior Questionnaire, (IBQ), Italian Pain Questionnaire (IPQ), and Cold Pressor Test (CPT) in a retrospective observational study. Results FM subjects displayed higher SSAS scores than the other groups. High SSAS score was associated with FM (OR=8.39; 95%CI: 5.43–12.46) but not OCP. Although FM has the highest prevalence of SD (x 2 =14.07; p=.007), high SSAS scores were associated with SD in OCP but not in FM. Conclusions Unlike in OCP, in FM high SSAS scores were independent of the presence of SD. From a biopsychosocial perspective, SSAS may be a factor associated with the onset of FM.

Objectives Advice, reassurance and education are recommended as first line treatments for musculoskeletal pain conditions such as low back pain. Osteopaths are registered primary contact allied health professionals in the Australian healthcare system who primarily manage acute and chronic musculoskeletal pain conditions. This study aimed to investigate the proportion of Australian osteopaths who do and do not utilise advice, reassurance and education (pain counselling) in their clinical practice, and determine the characteristics associated with the frequency of using pain counselling in clinical practice. Methods A secondary analysis of practice characteristics from a nationally representative sample of Australian osteopaths was undertaken. Participants completed a 27-item practice characteristics questionnaire between July-December 2016. Bivariate analyses were used to identify significant variables for inclusion in a backward multiple logistic regression model. Adjusted odds ratios (OR) were calculated for significant variables. Results Responses were received from 991 Australian osteopaths, representing 49% of the profession. Of these 264 (26.64%) indicated often utilising pain counselling, and 727 (73.36%) reported not often utilising pain counselling. Those who utilised pain counselling were more than twice as likely to report research evidence had a high impact on their clinical practice (OR 2.11), and nearly twice as likely to discuss physical activity with their patients (OR 1.84). Conclusions Pain counselling is under-utilised by nearly three quarters of the Australian osteopathic profession as a management strategy. Future studies are required to explore the reasons why most in the profession comprised in this sample are infrequently utilising this guideline recommendation. Given the frequency of chronic musculoskeletal pain conditions presenting to Australian osteopaths, strategies appear to be needed to advance the profession via professional development in accessing and using evidence-based care for pain conditions.

Objectives Bowel dysfunction is a major complication following open surgery for invasive cancer of the bladder that results in significant discomfort; complications and can prolong the length of stay. The incidence of postoperative ileus following open radical cystectomy has been reported as 23–40%. The median length of hospital stay after this surgery in the United Kingdom is 11 days. Standard analgesic techniques include wound infusion analgesia combined with systemic morphine or thoracic epidural analgsia. Combined erector spinae plane and intrathecal opioid analgesia is a novel technique that has been reported to be an effective method of providing perioperative analgesia thereby enhancing recovery after open radical cystectomy. Methods We performed a prospective study on the effectiveness of the novel analgesic technique (combined erector spinae plane and intrathecal opioid analgesia) in reducing the incidence of postoperative ileus, thereby facilitating early discharge following open radical cystectomy when compared to a contemporaneous control group receiving standard analgesia. Twenty-five patients received the novel analgesia while 31 patients received standard analgesia as a part of enhanced recovery programme. Standard analgesia arm included 14 patients who recived thoracic epidural analgesia (14/31, 45%) and 17 patients who received combined wound infusion analgesia and patient controlled analgesia with morphine (17/31, 55%). Primary outcome was the incidence of postoperative ileus. Secondary outcomes included length of hospital stay, tramadol consumption and time to bowel opening. Results Combined erector spinae plane and intrathecal opioid analgesia was associated with a reduced incidence of postoperative ileus (16 [4/25] vs. 65% [20/31], p<0.001), reduced time to first open bowel (4.4 ± 2.3 vs. 6.6 ± 2.3, p<0.001) and reduced median (IQR) length of hospital stay (7[6, 12] vs. 10[8, 15], p=0.007). There was no significant difference in rescue analgesia (intravenous tramadol) consumption. Complete avoidance of systemic morphine played a key role in improved outcomes. Conclusions ESPITO was successful in reducing postoperative ileus and length of hospital stay after open radical cystectomy when compared to standard analgesia within an enhanced recovery programme.

Objectives Shoulder pain is a prevalent problem and has a considerable impact on the use of primary and specialist health care in Norway. It is important to improve short-term recovery and reduce long-term consequences regarding pain and disability, the high costs of treatment and the amount of sick-leave. Treatment for non-specific shoulder pain is mainly non-operative. The aims of this study were to investigate if there are differences in main characteristics, pain and disability (SPADI-score) and psycho-social factors between patients in primary and specialist health care. Methods This cross-sectional study included patients consulting physiotherapy in primary health care and patients at an outpatient clinic in specialist health care. Well-known and tested questionnaires for these populations were used and variables were divided into clinical, sociodemographic, psycho-social, and shoulder pain and disability. Descriptive statistics were applied. Two-sample t -test and linear regression were used for continuous data whereas chi-square tests and logistic regression were applied to test differences in categorical data between the two study populations. Results Two hundred and 36 patients were recruited from primary health care (FYSIOPRIM, Physiotherapy In Primary Care) and 167 from specialist health care. Patients in primary health care reported less regular use of pain medication (30.7 vs. 61.3%) and fewer patients had symptom duration >12 months (41.9 vs. 51.0%). Furthermore, they reported lower pain intensity, less shoulder pain and disability (SPADI-score), lower scores on psycho-social factors, but higher on expectations of recovery. Conclusions Patients with shoulder pain treated in primary health care and in specialist health care are different according to factors such as duration of symptoms, pain and disability, and some of the psycho-social variables. However, the differences are small and the variations within the two study samples is large. Patients treated in primary health care seemed to be less affected and to have higher expectations concerning their recovery. However, based on our results we may question why many patients are referred to specialist health care rather than continuing treatment in primary health care.

Objectives The effect of stretching on joint range of motion is well documented, and although sensory perception has significance for changes in the tolerance to stretch following stretching the underlining mechanisms responsible for these changes is insufficiently understood. The aim of this study was to examine the influence of endogenous pain inhibitory mechanisms on stretch tolerance and to investigate the relationship between range of motion and changes in pain sensitivity. Methods Nineteen healthy males participated in this randomized, repeated-measures crossover study, conducted on 2 separate days. Knee extension range of motion, passive resistive torque, and pressure pain thresholds were recorded before, after, and 10 min after each of four experimental conditions; (i) Exercise-induced hypoalgesia, (ii) two bouts of static stretching, (iii) resting, and (iv) a remote, painful stimulus induced by the cold pressor test. Results Exercise-induced hypoalgesia and cold pressor test caused an increase in range of motion (p<0.034) and pressure pain thresholds (p<0.027). Moderate correlations in pressure pain thresholds were found between exercise-induced hypoalgesia and static stretch (Rho>0.507, p=0.01) and exercise-induced hypoalgesia and the cold pressor test (Rho=0.562, p=0.01). A weak correlation in pressure pain thresholds and changes in range of motion were found following the cold pressor test (Rho=0.460, p=0.047). However, a potential carryover hypoalgesic effect may have affected the results of the static stretch. Conclusions These results suggest that stretch tolerance may be linked with endogenous modulation of pain. Present results suggest, that stretch tolerance may merely be a marker for pain sensitivity which may have clinical significance given that stretching is often prescribed in the rehabilitation of different musculoskeletal pain conditions where reduced endogenous pain inhibition is frequently seen.

Objectives Ultra-endurance research interest has increased in parallel with an increased worldwide participation in these extreme activities. Pain-related data for the growing population of ultra-endurance athletes, however, is insufficient. More data is especially needed regarding the variation in the aging populations of these athletes. We have previously shown that peripheral and central pain sensitivity increases during an ultra-marathon. To further clarify these changes in pain sensitivity during ultra-endurance competition we investigated these variations in two age populations: Younger runners ≤ 39-year-old (younger) and an older group of runners being ≥ 40 years of age (older). Methods Subjects were recruited from ultra-marathon competitions held over a three-year period in Florida, USA. All courses were flat with either hard macadam surface or soft sandy trails; run in hot, humid weather conditions. Pressure pain threshold (PPT) was measured with a pressure algometer on the distal, dominant arm before and immediately after an ultra-marathon. Conditioned pain modulation (CPM) was also measured pre and post, immediately after the PPT by placing the non-dominant hand in a cold-water bath maintained at 13.5 ± 1.5 °C. The difference between the pre and post measurements for both PPT and CPM were calculated and referred to as ΔPPT and ΔCPM, respectively for analysis. Data were analyzed with a Mixed 2 × 2 (Within X Between) MANOVA. Results Both PPT and CPM decreased during the ultra-marathons (p<0.05) in the younger group of runners. In the older runners there was not a statistically significant decrease in PPT during the ultramarathons whereas CPM did significantly decrease statistically (p=0.031). The ΔPPT was less in the older group compared to the younger group (p=0.018). The difference between the younger and older groups ΔCPM approached statistical significance at p=0.093. Conclusions This statistical evidence suggests that the overall increase in peripheral and possibly central pain sensitivity was different between our age groups. Pain sensitivity during the ultra-marathon increased more in our younger group of runners than in our older group. This study suggests that there is an unidentified factor in an older population of ultra-marathon runners that results in an attenuated increase in pain sensitivity during an ultra-endurance activity. These factors may include a decreased innate immune response, lower fitness level, lower exertion during the ultra-marathon, variation in endorphin, enkephalin, endocannabinoid and psychological factors in the older age runners.

Objectives The present pilot study aims to investigate DNA methylation changes of genes related to fibromyalgia (FM) development and its main comorbid symptoms, including sleep impairment, inflammation, depression and other psychiatric disorders. Epigenetic modifications might trigger or perpetuate complex interplay between pain transduction/transmission, central pain processing and experienced stressors in vulnerable individuals. Methods We conducted DNA methylation analysis by targeted bisulfite NGS sequencing testing differential methylation in 112 genomic regions from leukocytes of eight women with FM and their eight healthy sisters as controls. Results Tests for differentially methylated regions and cytosines brought focus on the GRM2 gene, encoding the metabotropic glutamate receptor2. The slightly increased DNA methylation observed in the GRM2 region of FM patients may confirm the involvement of the glutamate pathway in this pathological condition. Logistic regression highlighted the simultaneous association of methylation levels of depression and inflammation-related genes with FM. Conclusions Altogether, the results evidence the glutamate pathway involvement in FM and support the idea that a combination of methylated and unmethylated genes could represent a risk factor to FM or its consequence, more than single genes. Further studies on the identified biomarkers could contribute to unravel the causative underlying FM mechanisms, giving reliable directions to research, improving the diagnosis and effective therapies.

Objectives In this sub-study of the ‘Paracetamol and Ibuprofen in Combination’ (PANSAID) trial, in which participants were randomised to one of four different non-opioids analgesic regimen consisting of paracetamol, ibuprofen, or a combination of the two after planned primary total hip arthroplasty, our aims were to investigate the distribution of participants’ pain (mild, moderate or severe), integrate opioid use and pain to a single score (Silverman Integrated Approach (SIA)-score), and identify preoperative risk factors for severe pain. Methods We calculated the proportions of participants with mild (VAS 0–30 mm), moderate (VAS 31–60 mm) or severe (VAS 61–100 mm) pain and the SIA-scores (a sum of rank-based percentage differences from the mean rank in pain scores and opioid use, ranging from −200 to 200%). Using logistic regression with backwards elimination, we investigated the association between severe pain and easily obtainable preoperative patient characteristics. Results Among 556 participants from the modified intention-to-treat population, 33% (95% CI: 26–42) (Group Paracetamol + Ibuprofen (PCM + IBU)), 28% (95% CI: 21–37) (Group Paracetamol (PCM)), 23% (95% CI: 17–31) (Group Ibuprofen (IBU)), and 19% (95% CI: 13–27) (Group Half Strength-Paracetamol + Ibuprofen (HS-PCM + IBU)) experienced mild pain 6 h postoperatively during mobilisation. Median SIA-scores during mobilisation were: Group PCM + IBU: −48% (IQR: −112 to 31), Group PCM: 40% (IQR: −31 to 97), Group IBU: −5% (IQR: −57 to 67), and Group HS-PCM + IBU: 6% (IQR: −70 to 74) (overall difference: p=0.0001). Use of analgesics before surgery was the only covariate associated with severe pain (non-opioid: OR 0.50, 95% CI: 0.29–0.82, weak opioid 0.56, 95% CI: 0.28–1.16, reference no analgesics before surgery, p=0.02). Conclusions Only one third of participants using paracetamol and ibuprofen experienced mild pain after total hip arthroplasty and even fewer experienced mild pain using each drug alone as basic non-opioid analgesic treatment. We were not able, in any clinically relevant way, to predict severe postoperative pain. A more extensive postoperative pain regimen than paracetamol, ibuprofen and opioids may be needed for a large proportion of patients having total hip arthroplasty. SIA-scores integrate pain scores and opioid use for the individual patient and may add valuable information in acute pain research.

Objectives Complex regional pain syndrome (CRPS) is a persistent pain condition which is often misunderstood and poorly managed. Qualitative studies are needed to explore the lived experience of the condition and to better understand patient perspectives on their management experiences and needs. The aim of this study was to explore the lived experience of CRPS in Australia, including exploration of their perceptions of care and advice received from healthcare professionals. Methods A qualitative study with individual in-depth semi-structured, face-to-face interviews was performed (n=15, 80% female, average time elapsed since diagnosis 3.8 years). Qualitative data were analysed using an inductive thematic analysis approach. Results Four main themes with associated subthemes were identified, representing the participants’ journey: (1) Life Changing Impact of CRPS (Subthemes: Impact on self, Impact on others); (2) Variable Experiences of Care (Subthemes: Helpful experiences of care, Unhelpful experiences of care); (3) Making Sense of CRPS (Subthemes: Knowledge and understanding, Dealing with unpredictability); and (4) Perceptions on Lessons Learned from Living with CRPS (Subthemes: Acceptance was an important part of the journey, Trial and error was necessary to find an individual way forward, Coping strategies). Conclusions The themes identified align to and expand on prior qualitative research findings in people with CRPS. It highlights the challenges people face related to their personal self, their close relationships and their social and work roles. It highlights the difficulties these people have in finding reliable, trust-worthy information. These findings suggest that healthcare professionals may benefit from education about how to better support people with CRPS, including helping people to navigate to the right care. Engaging people with CRPS in the development of educational resources should be a future research goal. It is recommended that patient perspectives are incorporated into the development of care pathways for CRPS.

Objectives Opioids are often used in treatment of severe pain, although many patients experience gastrointestinal side-effects like constipation. The aim of the current study was to investigate changes in colonic volume, as the result of both colonic motility and fluid transport, in healthy volunteers during opioid treatment with tapentadol as compared with oxycodone and placebo. Methods In a randomized, double-blind, cross-over study, 21 healthy male volunteers were administered equianalgesic dosages of oral tapentadol (50 mg bid), oxycodone (10 mg bid) or corresponding placebo for 14 days. Segmental colonic volumes were quantified using T2-weighted magnetic resonance images, and gastrointestinal side-effects were assessed with questionnaires. Results Total colonic volume increase during treatment was higher during tapentadol and oxycodone treatment (median 48 and 58 mL) compared to placebo (median −14 mL, both p≤0.003). Tapentadol (and placebo) treatment resulted in more bowel movements (both p<0.05) and softer stool consistency as compared with oxycodone (both p<0.01). Only oxycodone treatment was associated with increased constipation, straining during defecation, and tiredness (all p≤0.01). The colonic volume increase during treatment was directly associated with softer stools during tapentadol treatment (p=0.019). Conclusions Tapentadol treatment increased colonic volume without leading to harder stools, likely as the opioid sparing effects result in less water absorption from the gut lumen. Oxycodone treatment also increased colonic volume, but with a simultaneous increase in stool dryness and gastrointestinal and central nervous system side-effects. The results confirm that tapentadol treatment may be advantageous to oxycodone regarding tolerability to pain treatment.

Electrode migration is a challenge, even with adequate anchoring techniques, due to the high mechanical stress on components of occipital nerve stimulation (ONS) for headache disorders. When a lead displacement of an ONS implant is diagnosed, there are currently different approaches described for its management. Nevertheless current neuromodulation devices are designed like a continuum of components without any intermediate connector, and if a lead displacement is diagnosed, the solution is the complete removal of the electrode from its placement, and its repositioning through an ex-novo procedure. The described technique can allow ONS leads to be revised while minimizing the need to reopen incisions over the IPG, thus improving patients’ intraoperative and postoperative discomfort, shortening surgical time and medical costs, reasonably reducing the incidence of infective postoperative complications.