Volume 19, Issue 2

Background and aims There has been no comprehensive evaluation of the efficacy of transcutaneous electric nerve stimulation (TENS) for acute low back pain (LBP). The aim of this systematic review was to investigate the efficacy and safety of TENS for acute LBP. Methods We searched MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, CENTRAL, CINAHL and PsycINFO (inception to May 2018) for randomised placebo controlled trials. The primary outcome measure was pain relief in the immediate term (within 2-weeks of administration) assessed using the 100 mm visual analogue scale. A mean difference of at least 10 points on the 100-point pain scale was considered clinically significant. Methodological quality of the eligible studies was assessed using the PEDro scale and overall quality assessment rating was assessed using GRADE. Results Three placebo controlled studies ( n  = 192) were included. One low quality trial ( n  = 63) provides low quality evidence that ~30 min treatment with TENS in an emergency-care setting provides clinically worthwhile pain relief for moderate to severe acute LBP in the immediate term compared with sham TENS [Mean Difference (MD) – 28.0 (95% CI – 32.7, −23.3)]. Two other studies which administered a course of TENS over 4–5 weeks, in more usual settings provide inconclusive evidence; MD −2.75 (95% CI −11.63, 6.13). There was limited data on adverse events or long term follow-up. Conclusions The current evidence is insufficient to support or dismiss the use of TENS for acute LBP. Implications There is insufficient evidence to guide the use of TENS for acute LBP. There is low quality evidence of moderate improvements in pain with a short course of TENS (~30 min) during emergency transport of patients to the hospital. Future research should evaluate whether TENS has an opioid sparing role in the management of acute LBP.

Background and aims Recent research indicates a previously unknown low-grade systemic or neurogenic inflammation in groups of chronic pain (CP) patients. Low-grade inflammation may have an important role in symptoms that have previously not been well depicted: widespread pain, tiredness and cognitive dysfunctions frequently seen in severely impaired CP patients. This study aimed to investigate the plasma inflammatory profile in a group of very complex CP patients at baseline and at a 1-year follow-up after participation in a cognitive behavior therapy (CBT)-based multimodal pain rehabilitation program (PRP). Methods Blood samples were collected from 52 well-characterized CP patients. Age- and sex-matched healthy blood donors served as controls. The samples were analyzed with a multiple Proximal Extension Analysis allowing a simultaneous analysis of 92 inflammation-related proteins consisting mainly of cytokines, chemokines and growth-factors. At follow-up, 1-year after participation in the RPR samples from 28 patients were analyzed. The results were confirmed by a multi-array technology that allows quantitative estimation. Results Clear signs of increased inflammatory activity were detected in the CP patients. Accepting a false discovery rate (FDR) of 5%, there were significant differences in 43/92 inflammatory biomarkers compared with the controls. In three biomarkers (CXCL5, SIRT2, AXIN1) the expression levels were elevated more than eight times. One year after the PRP, with the patients serving as their own controls, a significant decrease in overall inflammatory activity was found. Conclusions Our results indicate that the most impaired CP patients suffer from low-grade chronic systemic inflammation not described earlier with this level of detail. The results may have implications for a better understanding of the cluster of co-morbid symptoms described as the “sickness-syndrome” and the wide-spread pain seen in this group of patients. The decrease in inflammatory biomarkers noted at the follow-up after participation in the PRP may reflect the positive effects obtained on somatic and psycho-social mechanisms involved in the inflammatory process by a rehabilitation program. Besides the PRP, no major changes in medication or lifestyle factors were implemented during the same period. To our knowledge, this is the first study reporting that a PRP may induce inflammatory-reducing effects. Further studies are needed to verify the objective findings in CP patients and address the question of causality that remains to be solved. Implications The findings offer a new insight into the complicated biological processes underlying CP. It may have implications for the understanding of symptoms collectively described as the “sickness-syndrome” – frequently seen in this group of patients. The lowering of cytokines after the participation in a PRP indicate a new way to evaluate this treatment; by measuring inflammatory biomarkers.

Background and aims This study has two main aims: (1) To explore the overlap between classification criteria in patients with Chronic Widespread Pain (CWP) and (2) To explore the use of the Patient Generated Index (PGI) as a quality of life (QoL) measure in this patient group. Methods Patients with Widespread Pain (ICD-11: pain in four or more out of five bodily regions, i.e. the four quadrants and axially) in a tertiary pain outpatient clinic were assessed according to classification criteria for Fibromyalgia [FM, American College of Rheumatology (ACR) criteria of 1990, 2010, 2011 and 2016], Chronic Fatigue Syndrome [CFS, Fukuda, Canada and International Consensus Criteria (ICC)] and Bodily Distress Syndrome (BDS). Furthermore, patients completed the PGI to assess QoL, and electronic questionnaires including demographic variables and standardised patient-reported outcome measures (PROMs). Results All patients ( n =33) fulfilled the criteria for musculoskeletal type single-organ BDS, 81.8% met the 2016 modified criteria for FM, 30.3% met the Canada criteria for CFS and 24.2% met the criteria for multi-organ type BDS. There was substantial agreement between the 2016 and the 2011 and 2010 criteria sets for FM compared to the 1990 criteria (κ=0.766 and 0.673 compared to 0.279). Patients generally scored low on the PGI, indicating poor QoL (mean PGI 28.9, SD 19.8, range 0–100). Conclusions Our findings support the use of the term musculoskeletal type single-organ BDS to describe patients with CWP and the 2016 revision of the FM criteria. The PGI provides useful clinical information which is not captured by standardised PROMs. Implications The terminology of CWP has become less ambiguous as the new ICD-11 is closely related to the generalised pain criterion of the modified 2016 FM definition. Studies based on the 1990 classification criteria for FM should not be directly compared to studies based on later criteria set. The PGI may be a supplement to other measurements to portray patients’ individual concerns in patients with complex symptom disorders.

Background and aims Complex Regional Pain Syndrome (CRPS) often recovers spontaneously within the first year, but when it becomes chronic, available rehabilitative therapies (pharmacological management, physiotherapy, and psychological intervention) have limited effectiveness. This study examined the effect of a 12-week intensive outpatient rehabilitation on pain relief and function in chronic CRPS patients. Rehabilitation program included memantine and morphine treatment (added to patient’s prior pain medication) and concurrent psychological and physiotherapeutic intervention. Primary outcome measure was a change in CRPS symptom count and secondary outcomes were motor performance, psychological factors, pain intensity, and quality of life. Methods Ten patients with chronic upper limb CRPS I (median 2.9 years, range 8 months to 12 years) were recruited to the study and were assessed before and after the intervention. Hand motor function of the patients was evaluated by an independent physiotherapist. There were standardized questionnaires for depression, pain anxiety, pain acceptance, quality of life, and CRPS symptom count. In addition, psychological factors were evaluated by a semi-structured interview. Severity of experienced pain was rated at movement and at rest. In addition, a video experiment of a hand action observation was conducted pre- and post-intervention to study possible change in neuronal maladaptation. Intervention consisted of pharmacological, psychological and physiotherapeutic treatment. First, 10 mg daily morphine was started and increased gradually to 30 mg daily, if tolerated. After 30 mg/day or tolerated dose of morphine was achieved, 5 mg daily memantine was started and increased gradually to 40 mg, if tolerated. Psychological intervention consisted of weekly group sessions, using cognitive and behavioral methods (relaxation, behavioral activation, and exposure) and acceptance and commitment therapy (ACT) and daily home practice. Physiotherapeutic intervention consisted of graded motor imagery and physiotherapy exercises with weekly group sessions and/or individual guidance by the physiotherapist, and individual exercise of the affected upper limb. Results Multimodal intensive intervention resulted in significant decrease in CRPS symptom count. The effect was strongest in motor and trophic symptoms (19% decrease after intervention) and in sensory symptoms (18% decrease). Additionally, improvement was seen in some, but not all, secondary outcomes (movement pain, motor symptoms, change in perceptions during video experiment of hand actions, and summary index with motor functioning, pain, and psychological factors). There were no dropouts. Conclusions Intensive 12-week multimodal intervention reduced some CRPS symptoms but was not sufficient to alter patients’ rest pain, distress, or quality of life. Implications These results support the efficacy of an interdisciplinary rehabilitation program for pain and function in chronic CRPS patients. After intervention, some CRPS symptoms reduced and function improved, but distress and quality of life were unchanged. This may be due to the relatively short duration of this program; to delayed effects; to particular cognitive problems of CPRS patients; and/or to low distress levels at baseline that make statistically significant reduction less likely.

Background and aims The relative contribution of patient-related factors and intraoperative nerve damage for the development of chronic pain after surgery is unclear. This study aimed to examine chronic pain after bilateral thoracotomy. We hypothesized, that individual patient-related risk factors would be important resulting in an intraindividual uniformity of pain and hyperphenomena between the two sides of the thorax. Methods Twenty patients who had undergone lung transplantation via bilateral thoracotomy 6–12 months previously were included from the Danish Lung Transplant program, Rigshospitalet, Denmark, from October 2016 to August 2017. All patients answered questionnaires about pain in and around the scar, completed the Neuropathic Pain Symptom Inventory, and underwent bedside examination for hyperphenomena (brush- and cold-evoked allodynia, pinprick hyperalgesia) and pinprick hypoalgesia. Results Nine patients reported spontaneous pain bilaterally, five patients had pain on one side only, and six patients had no pain. Hyperphenomena were present on both sides of the thorax in 13 patients, on one side in four patients, and three patients had no hyperphenomena. The intraindividual uniformity of pain ( p =0.029) and hyperphenomena ( p =0.011) between the two sides of the thorax suggests that patient-related factors play an important role in the development of chronic pain. Conclusions The results of the present study provide support for the hypothesis of an individual predisposition for the development of chronic pain after thoracotomy. Implications Patient-related risk factors contribute to the development of chronic pain after thoracotomy. This result most likely can be transferred to chronic pain after other surgical procedures and therefore help us understand risk factors for chronic pain after surgery.

Background and aims Endogenous pain modulation can be studied in humans by conditioned pain modulation (CPM): pain induced by a test stimulus is attenuated by a distantly applied noxious conditioning stimulus. The detection of impaired CPM in individual patients is of potential importance to understand the pathophysiology and predict outcomes. However, it requires the availability of reference values. Methods We determined reference values of CPM in 146 pain-free subjects. Pressure and electrical stimulation were the test stimuli. For electrical stimuli, we recorded both pain threshold and threshold for the nociceptive withdrawal reflex. Cold pressor test was the conditioning stimulus. The 5th, 10th and 25th percentiles for the three tests were computed by quantile regression analyses. Results The average thresholds increased after the conditioning stimulus for all three tests. However, a subset of subjects displayed a decrease in thresholds during the conditioning stimulus. This produced negative values for most of the computed percentiles. Conclusions This study determined percentile reference values of CPM that can be used to better phenotype patients for clinical and research purposes. The negative value of percentiles suggests that a slightly negative CPM effect can be observed in pain-free volunteers. Implications Pain facilitation rather than inhibition during the conditioning stimulus occurs in some pain-free volunteers and may not necessarily represent an abnormal finding.

Background and aims A targeted pain program may prevent the progression and subsequent occurrence of chronic pain in adolescents. This study tested the effectiveness of a new acceptance and commitment therapy -based pain management intervention, using physical and psychological functions as the outcomes. The objective was also to determine whether Pediatric Pain Screening Tool risk profiles function as outcome moderator in the current sample. A valid screening tool would enable the program development. Methods Thirty-two consecutive adolescent patients (13–17 years old) with idiopathic recurrent musculoskeletal pain completed the study. The intervention comprised acceptance and commitment therapy-oriented multidisciplinary treatment. Pediatric Pain Screening Tool, pain frequency, functional disability, school attendance, physical endurance, depressive symptoms, and catastrophizing coping style were measured before treatment (baseline) and again at 6 and 12 months after the initiation of treatment. To test the effectiveness of the new program, we also determined whether the original risk classification of each patient remained constant during the intervention. Results The intervention was effective for high-risk patients. In particular, the pain frequency decreased, and psychosocial measures improved. In post-intervention, the original risk classification of seven patients in the high-risk category changed to medium-risk. PPST classification acted as a moderator of the outcome of the current program. Conclusions The categorization highlighted the need to modify the program content for the medium-risk patients. The categorization is a good tool to screen adolescent patients with pain. Implications The results support using the Pediatric Pain Screening Tool in developing rehabilitation program for pediatric musculoskeletal pain patients. According to the result, for adolescent prolonged musculoskeletal pain patients the use of ACT-based intervention program is warranted.

Background and aims Following spinal cord injury (SCI), a majority of individuals may develop neuropathic pain, which further reduces quality of life. Pain is difficult to treat by medication; in fact, medication overuse may aggravate neuropathic pain in SCI by causing central sensitization (CS): a mechanism of hyper-reactivity of the dorsal horn neurons in the spinal cord with amplified cerebral pain response. The purpose of this study was to examine the presence of neuropathic pain and CS above the spinal lesion in SCI, and to investigate whether injury characteristics or medication influenced pain response. Methods Twenty-four SCI patients with various injury characteristics (eight subacute, traumatic injuries, eight chronic, traumatic injuries, eight non-traumatic injuries) and 12 able-bodied controls underwent sensory testing:pressure algometry, Von Frey filaments (sensitivity), and repetitive pinprick stimulation (pain windup). SCI participants also fulfilled a modified version of the McGill Pain Questionnaire. Data were analyzed regarding (i) SCI patients compared with controlgroup and (ii) SCI subgroup comparison (grouped by a) injury characteristics and (b) intake of analgesics, where low-medicated subgroup were prescribed only non-opioids and high-medicated potent opioids). Results Neuropathic pain was present in 21 of 24 SCI patients. Chronic and non-traumatic SCI patients reported considerably higher present pain intensity than sub-acute traumatic SCI patients on a five-point scale (3.13±0.99, 1.75±1.75 and 0.13±0.35, respectively, p <0.005). Reduced pressure pain detection thresholds (PPDT) were found in SCI patients at several supra-lesional anatomical points compared to controls. Contrarily, tactile detection thresholds were higher in SCI. SCI subgroup analyses showed that i) the low-medicated SCI subgroup displayed significantly lower PPDT compared to the high-medicated subgroup, ii) pain-windup was present in all subgroups although the sub-acute and non-traumatic subgroups displayed lesser pain windup than controls, and the chronic SCI subgroup mainly displayed higher pain windup. Conclusions The reduced PPDT found above lesion suggests the presence of CS in SCI. However, findings regarding SCI subgroup comparison did not support our hypothesis that more medication leads to increased CS. Implications The development of CS may complicate diagnosis and pain treatment following SCI. Prospective studies of SCI with a healthy control group are needed.

Background and aims Pain is the most common reason for delayed discharge after day-case laparoscopic cholecystectomy. This study investigates a simple five-item questionnaire in evaluating the risk of postoperative pain in day-case cholecystectomy and the efficacy and safety of single-dose preoperative pregabalin on patients with multiple risk factors for pain. There are no previous studies on targeting adjuvant pain treatment based on the individual risk factors like the preoperative state of anxiety, acute or chronic pain, and the expectation of pain in day-case surgery. Methods One hundred and thirty patients scheduled for day-case laparoscopic cholecystectomy were evaluated with a five-item questionnaire assessing the risk for postoperative pain. The patients with multiple risk factors ( n =60) were randomized to receive either pregabalin 150 mg or placebo, 1 h before surgery. The primary outcome was abdominal pain intensity on numerical rating scale (NRS) 1 h after surgery. Pain, analgesic consumption and adverse effects during first three postoperative days, and the length of hospital stay were also recorded. Results Pregabalin 150 mg given as an adjuvant analgesic preoperatively did not decrease postoperative abdominal pain or opioid consumption in the first hour after surgery compared to placebo in a preselected group of patients with multiple risk factors for postoperative pain ( p =0.31). Preoperative anxiety assessed with a scale of 0–10 had a positive association with postoperative pain ( p =0.045). Conclusions and implications This was the first trial on systematically selecting patients with a high-risk factor profile for postoperative pain as a target for a preventive adjuvant analgesic intervention. Although numerous previous studies have identified various risk factors, including those used in the current trial, it seems to be challenging to use these risk factors as predictive tools for targeting adjuvant analgesics in day-case surgery. Preoperative anxiety has a positive association with postoperative pain in day-case laparoscopic cholecystectomy, and this should be taken into account when treating these patients.

Background and aims The co-morbidity between pain and depression is a target of interest for treatment. However most of the published literature on the topic has used clinical cohorts as the population of interest. The goal of this study was to use a nationally representative sample to explore how health outcomes varied across pain and depression status in a cohort sampled from the general US population. Methods This was a cross-sectional analysis of adults ≥18 years in the 2009–2010 National Health and Nutrition Examination Survey. The cohort was stratified into: no pain/depression, pain alone, depression alone, and pain with depression. The primary outcome was self-reported general health status, and secondary outcomes were healthcare visits, overnight hospital stays and functional limitation. Survey weighted logistic regression was used to adjust for potential confounders. Results The cohort consisted of 4,213 individuals, of which 186 (4.4%) reported concurrent pain and depression. 597 (14.2%) and 253 (6.0%) were classified with either pain or depression alone, respectively. The majority of individuals with co-morbid pain and depression reported poor health (65.1%, p <0.001) and were significantly more likely than those with neither condition to rate their health as poor after adjustment (OR: 7.77, 95% CI: 4.24–14.26, p <0.001). Those with pain only or depression only were also more likely to rate their health as poor, albeit to a lesser extent (OR: 2.21, 95% CI: 1.21–2.34, p <0.001; OR: 3.75, 95% CI: 2.54–5.54, p <0.001, respectively). A similar pattern was noted across all secondary outcomes. Most notably, those with co-morbid pain and depression were the most likely to endorse functional limitation (OR: 13.15, 95% CI: 8.00–21.61, p <0.001). Comparatively, a similar trend was noted amongst those with pain only or depression only, though with a reduced effect size (OR: 4.23, 95% CI: 3.12–4.77, p <0.001; OR: 5.13, 95% CI: 3.38–7.82, p <0.001). Conclusions Co-morbid pain and depression in the general population resulted in markedly worse outcomes versus isolated pain or depression. Further, the effect appears to be synergistic. Given the substantial burdens of pain and depression, future treatments should aim to address both conditions simultaneously. Implications As a result of the co-morbidity between pain and depression, patients presenting with either condition should increase the index of suspicion among clinicians and prompt screening for the reciprocal condition. Early intervention for co-morbid pain and depression has the potential to mitigate future incidence of chronic pain and major depression.

Background and aims The RELIEF (Real Life) study by AstraZeneca was designed as an observational study to validate a series of Patient Reported Outcome (PRO) questionnaires in a mixed population of subjects with neuropathic pain (NP) coming from diabetes, neurology and primary care clinics. This article is an analysis of a subset of the information to include the medications used and the effects of pharmacological treatment over 6 months. The RELIEF study was performed during 2010–2013. Methods Subjects were recruited from various specialty clinics and one general practice clinic across Canada. The subjects were followed for a total of 2 years with repeated documentation of their status using 10 PROs. A total of 210 of the recruited subjects were entered into the data base and analyzed. Of these, 123 had examination-verified painful diabetic neuropathy (PDN) and 87 had examination-verified post-traumatic neuropathy (PTN). To evaluate the responsiveness of the PROs to change, several time points were included and this study focusses primarily on the first 6 months. Subjects also maintained a diary to document all medications, both for pain and other medical conditions, including all doses, start dates and stop dates, that could be correlated to changes in the PRO parameters. Results RELIEF was successful in being able to correlate the validity of the PROs and this data was used for further AstraZeneca Phase 1, 2, and 3 clinical trials of NP. To our surprise, there was very little change in pain and low levels of patient satisfaction with treatment during the trial. Approximately 15% of the subjects reported improvement, 8% worsening of pain, the remainder reported pain unchanged despite the use of multiple medications at multiple doses, alone or in combination with frequent changes of medications and doses over the study. Those taking predominantly NSAIDs (COX-inhibitors) did no worse than those taking the standard recommended medications against NP. Conclusions Since this is a real-life study, it reflects the clinical utility of a variety of internationally recommended medications for the treatment of NP. In positive clinical trials of these medications in selected “ideal” subjects, the effects are not overwhelming – 30% are 50% improved on average. This study shows that in the real world the results are not nearly as positive and reflects information from non-published negative clinical trials. Implications We still do not have very successful medications for NP. Patients probably differ in many respects from those subjects in clinical trials. This is not to negate the use of recommended medications for NP but an indication that success rates of treatment are likely to be worse than the data coming from those trials published by the pharmaceutical industry.

Background and aims Posttraumatic stress disorder (PTSD) is related to more severe pain among chronic pain patients. PTSD is also related to dysfunctions or biases in several cognitive processes, including autobiographical memory. The autobiographical memories are our memories of specific personal events taking place over a limited amount of time on a specific occasion. We investigated how two biases in autobiographical memory, overgeneral memory style and negative emotional bias were related to pain, PTSD and trauma exposure in chronic pain patients. Methods Forty-three patients with diverse chronic pain conditions were recruited from a specialist pain clinic. The patients were evaluated for psychiatric diagnosis, with a diagnostic interview Mini-International Neuropsychiatric Interview (M.I.N.I) and for exposure to the most common types of traumatic events with the Life Event Checklist (LEC). The patients were tested with the 15-cue-words version of the Autobiographical Memory Test (AMT). In this test the participants are presented verbally to five positive, five neutral and five negative cue words and asked to respond with a personal, episodic memory associated with the cue word. The participant’s responses were coded according to level of specificity and emotional valence. Pain intensity was assessed on a Visual Analogy Scale (VAS) and extent of pain by marking affected body parts on a pre-drawn body figure. Comparisons on autobiographical memory were made between PTSD and non-PTSD groups, and correlations were computed between pain intensity and extent of pain, trauma exposure and autobiographical memory. Results PTSD and extent of pain were significantly related to more negatively emotionally valenced memory responses to positive and negative cue words. There were no significant difference in response to neutral cue words. PTSD status and pain intensity were unrelated to overgeneral autobiographical memory style. Conclusions A memory bias towards negatively emotionally valenced memories is associated with PTSD and extent of pain. This bias may sustain negative mood and thereby intensify pain perception, or pain may also cause this memory bias. Contrary to our expectations, pain, trauma exposure and PTSD were not significantly related to an overgeneral memory style. Implications Cognitive therapies that have an ingredient focusing on amending memory biases in persons with comorbid pain and PTSD might be helpful for this patient population. Further investigations of negative personal memories and techniques to improve the control over these memories could potentially be useful for chronic pain treatment.

Background and aims While the Nordic countries have considerably stricter controls on opioid prescribing for chronic non-cancer pain than other countries, previous research has warned that prescription of strong opioids is increasing. This study examines consumption of and developments in dispensed prescribed opioids to individuals receiving ambulatory care from 2006 to 2017, using publicly available data from each of three Nordic countries’ national prescription registries. Methods Repeated, cross-sectional design. One-year prevalence of all dispensed prescribed opioids in ATC N02A group were reported for Norway, Denmark, and Sweden in the period 2006–2017 by gender. One-year prevalence of the weak opioids tramadol and codeine and the strong opioid oxycodone were then reported separately over this period for each country. The mean defined daily dose (DDD) per user per year, an estimate of the amount of opioids prescribed, was reported for each of the three opioids in 2016. Results Patterns of dispensed prescribed opioids differ greatly between 2006 and 2017 and between countries, with tramadol increasing in Norway, codeine declining across the board, and oxycodone increasing in all three countries. Norway exceeded Sweden and Denmark in prevalence of all dispensed prescribed opioids, with 12.1% of the female Norwegian population and 9.2% of the male Norwegian population dispensed at least one prescribed opioid as an outpatient in 2016. Norway’s high overall prevalence rates are tempered by dispensing the lowest mean doses of both weak opioids compared to Sweden. Similarly, Sweden dispenses the lowest mean doses of oxycodone but to the largest proportion of its population (3.0%). Conclusions Significant shifts have occurred in the dispensing of prescribed opioids in Norway, Sweden, and Denmark over the past 12 years. The increasing prevalence of oxycodone in all three countries should continue to be monitored. Prescription registries provide a wealth of publicly available data that can be used to monitor and to guide prescribing policies in a more knowledge-based direction.

Background and aims Chronic pelvic pain (CPP) in women is a complex condition that can seriously impact health and quality of life. Clinical guidelines for CPP place great demands on healthcare professionals, as they require both specialized knowledge about the pelvic area and knowledge of the mechanisms of chronic pain. To ensure best possible assessment and treatment of these women it is important to bring about more knowledge of the special CPP features. The purpose of this paper is to describe the characteristics of women with CPP evaluated at the University Hospital of North Norway, and further referred to physiotherapy. The frequency of having a history of abuse or previous pelvic surgery will also be reported, and analyses performed to investigate if subjective health status differs between women with and without these experiences. Methods We collected cross-sectional data from 62 women with CPP aged 20–65 (mean age 38.0), referred to physiotherapy after assessment by medical specialists. Data were collected by semi-structured interviews for demographic variables and medical history, and self-administered questionnaires on pain intensity, sexual function, urinary incontinence (UI), anal incontinence (AI), obstructed defecation syndrome (ODS), subjective health complaints (SHC) and symptoms of anxiety and depression. Results Pain duration of more than 10 years was reported by 42%, mean pain score was 4.7/10, and analgesics were used weekly by 48%. Previous pelvic or abdominal surgery was reported by 71%, and sick leave >12 weeks the last year by 34%. Reduced sexual desire was reported by 78%, dyspareunia by 73%, UI by 54%, AI by 23%, and obstructed defecation syndrome (ODS) by 34%. More than 90% reported musculoskeletal or pseudoneurologic complaints. Anxiety and depression scores defined as requiring treatment were reported by 40%. Abuse was reported by 50%, and associated with significantly more reports of ODS ( p =0.02), more SHC ( p =0.02) and higher anxiety scores ( p =0.009). Analgesic use and sick leave were significantly higher both among women with a history of abuse ( p =0.04 and p =0.005) and among those with previous surgery ( p =0.04 and p =0.02). Women with previous surgery reported significantly lower pain intensity during intercourse than those without previous surgery ( p =0.008). Conclusions Women with CPP have complex symptoms and high scores for both physical and psychological complaints. Women exposed to abuse have especially high scores related to analgesic use, sick leave, ODS, anxiety and SHC. Women with previous surgery report more analgesic use and sick leave, and lower pain intensity during intercourse, than those without previous surgery. Implications This study illustrates the complexity of CPP and highlights the need for health professionals to have specialized knowledge of the possible features of the condition. Previous abuse seems to be more associated with poor scores on several health outcomes than surgery, but this needs to be investigated further.

Background and aims Chronic pain is a leading cause to years lived with disability worldwide. However, few of the interventions used in pain medicine have proven efficacy, and evidence from the existing studies may not be valid for the general pain population. Therefore, it is of utmost need that we describe chronic pain conditions in their most relevant aspects, their various guises, as well as the real world outcomes of our clinical interventions. The most obvious and crude way to make these assessments are through large registries where patient characteristics, treatment characteristics (including but not limited to what, when, how often and by whom), treatment outcomes and patient outcomes are scrutinized and recorded. Methods and results This article describes in detail the design and baseline data of the comprehensive Oslo University Hospital Pain Registry (OPR). OPR is the local registry of the largest university and interdisciplinary outpatient pain clinic in Norway. Data registration started in October 2015, and approximately 1,000 patients are assessed and treated at the clinic each year. During the first 2 years of running the OPR (through September 2017), a total of 1,712 patient baseline reports were recorded from 2,001 patients. Clinicians enter data about relevant treatments and interventions, while patients provide self-reported data on aspects related to pain and pain management. The patients complete an electronic registration immediately before their first consultation at the outpatient pain clinic. The baseline questions of the OPR cover: Basic demographics; The Modified Oswestry Disability Index to assess general function; A pain drawing to assess pain location; Questions regarding the temporal aspects of pain; Six 0–10 Numeric Rating Scales to assess pain intensity and bothersomeness; The EQ-5D-5L to measure health-related quality of life; The Hopkins Symptom Check List-25 to assess psychological distress; A single question about self-rated health; The general self-efficacy scale to assess the patient’s perceived self-efficacy; The Bodily Distress Syndrome checklist to assess functional disorders; The Injustice Experience Questionnaire to assess whether the patients experience injustice; Chalder Fatigue Questionnaire to assess fatigue; The Insomnia Severity Index to assesses the levels of insomnia symptoms; The Pain Catastrophizing Scale to measure pain catastrophizing and exaggerated negative orientation toward pain stimuli and pain experience; And the SF36v2 to assess patients’ self-report of generic health and wellbeing. The baseline data show that chronic pain patients have a high degree of negative impact in all aspects of their lives. Conclusions and implications The OPR is the most comprehensive pain registry for multidisciplinary and interdisciplinary outpatient pain clinics in Norway. Detailed design of the registry and key baseline data are presented. Registries are of great value in that they enable real world effectiveness outcomes for patients with chronic pain conditions. The OPR can thus serve as a model for similar initiatives elsewhere. The OPR cohort may also serve as a historical control in future studies, both with experimental and observational design.

Background and aims Patellofemoral pain (PFP) is a common knee condition causing pain around or behind the kneecap which is exacerbated by certain activities. Traditionally it has been viewed as a self-limiting condition. Recent research proves this is not the case and the evidence for poor long-term outcomes is growing. Whilst the evidence base for PFP treatment and the understanding of its aetiology is improving, it remains a complex and difficult to treat condition. In many physical conditions, it has been shown that anxiety and depression negatively affect both their management and duration. It is unclear how prevalent anxiety and depression are in PFP. This study aimed to identify the prevalence of anxiety and depression in people living with PFP in the UK. Methods In order to investigate this, a cross-sectional online survey was undertaken. Four hundred participants with self-reported symptoms of PFP were recruited through a tailored social media campaign, using modified snowball sampling. Eligibility criteria were (i) aged between 18 and 44, (ii) self-reported symptoms of PFP (using accepted criteria) (iii) resident in the UK. Exclusion criteria were previous history of patella dislocation or previous surgery to affected knee. The survey recorded demographic information, previous treatment for both PFP and anxiety and depression, the Hospital Anxiety and Depression Scale and the Anterior Knee Pain Scale. Ethical approval was gained from a University of Plymouth Ethics Committee. Results Half (49.5%; n =198) of respondents were classified as experiencing anxiety and 20.8% ( n =83) as experiencing depression. The levels of anxiety and depression identified in this study are higher than those found in the general population (5.9–7.8% and 3.3–7.8%, respectively). This mirrors results which have been reported in other studies into PFP in different settings and with other musculoskeletal conditions, such as osteoarthritis and contracted shoulder. Conclusions Anxiety and depression are more common in people living with PFP than in the general population. These findings support the need for greater research into the effects of psychological factors, such as anxiety and depression, in PFP. A key area of future research will be to determine whether these psychological factors affect treatment outcomes in people living with PFP. Implications This is the first study to investigate the prevalence of anxiety and depression in people living with patellofemoral pain in the UK. This study shows that anxiety and depression are very common in people living with patellofemoral pain. The need for further work into the effects of psychological factors in patellofemoral pain is indicated.

Background and aims Interpreting pain- and illness-related stimuli as health-threatening is common among chronic pain patients but also occurs in the general population. As interpretation bias (IB) may affect pain perception and might even play part in the development and maintenance of chronic pain, it is important to improve our understanding of this concept. Several studies suggest an association between IB and pain-related anxiety. However, those studies often rely on verbal and pictorial IB tasks that do not entail a threat of actual pain, therefore lacking personal relevance for healthy participants. The current study investigated whether healthy individuals show an IB towards ambiguous health-related stimuli in a context of actual pain threat, and explored whether this bias is associated to pain anxiety constructs. Methods Thirty-six healthy participants were conditioned to expect painful electrocutaneous shocks (unconditioned stimulus – US) after health-threat words (CS+) but not after neutral (non-health-threat) words (CS−) in order to establish fear of pain. Subsequently, they completed a verbal interpretation task that contained new CS+ and CS− stimuli as well as ambiguous non-reinforced health-threat and non-health-threat words. IB was assessed through shock expectancy ratings and startle responses to ambiguous and evident health threatening or neutral word stimuli. Pain-related anxiety was measured with validated questionnaires. Results The results show a general IB towards ambiguous health-related words on pain expectancies but not on startle response. An exploratory analysis suggests that this effect exists irrespective of pain-related anxiety levels which however may be due to a lack of power. Conclusion We present a novel experimental paradigm employing actual health threat that captures IB towards health-related stimuli in healthy individuals. Taken together, results provide evidence for the further consideration of IB as a latent vulnerability factor in the onset and maintenance of pain chronicity. In contrast to previous studies employing a safe, pain-free context, we found that healthy participants show an IB towards ambiguous health-related stimuli, when confronted with pain threat. Implications Like chronic pain patients, healthy individuals display an IB towards health-threat stimuli when these stimuli become personally relevant by carrying information about pending health threat. Therefore, the presented paradigm could be valuable for pain-related cognitive bias research in healthy participants as it may have a higher ecological validity than previous study designs. Future studies will have to elucidate the influence of anxiety constructs on IB in larger samples.

Background and aims Prior research indicates that swearing increases pain tolerance and decreases pain perception in a cold pressor task. In two experiments, we extend this research by testing whether taboo hand gesticulations have a similar effect. Methods Study 1 focused on males and females who, across two trials, submerged an extended middle finger (taboo) and an extended index finger (control) in ice water until discomfort necessitated removal. Study 2 focused exclusively on pain perception in males who, across three trials, submerged their hand, flat, with extended middle finger and with extended index finger, for 45 s each. Results In study 1 taboo gesticulation did not increase pain tolerance or reduce pain perception compared with the index finger control condition, as a main effect or as part of an interaction with condition order. While there was a gesture×gender interaction for pain tolerance, this was driven by an increased pain tolerance for the index finger gesture for women but not men. The results of study 2 again showed that taboo gesticulation did not lower pain perception, although it did increase positive affect compared with both non-taboo gesture conditions. Conclusions Taken together these results provide only limited evidence that taboo gesticulation alters the experience of pain. These largely null findings further our understanding of swearing as a response to pain, suggesting that the activation of taboo schemas is not sufficient for hypoalgesia to occur.

Background and aims Pain is a prevalent problem in many countries. Women are more often on sick-leave for pain than men. Such gender differences have been explained through biological factors, different demands for on the job market, and home conditions. Fewer studies have focused on how gender stereotypes may bias the medical assessment of pain patients. The aim of the present research was to investigate if a gender bias in medical students’ evaluations of chronic pain patients can contribute to explaining the gender differences in sick-leave due to pain. Specifically, we investigated whether medical students’ estimates of a patient’s accuracy of their own work ability and amount of domestic work differed between female and male patients, and how such estimates influenced the medical students’ judgments of the patient’s work ability. Methods Medical students ( n =137; 60 women; 74 men; three unspecified) read a vignette describing a patient with pain and filled out a questionnaire. The vignette was identical and gender neutral, except for the name of the patient signaling gender. A between-subjects experimental design was used in which participants were randomly assigned to an experimental condition. Participants then judged the patient’s work ability, the accuracy of the patient’s self-assessed work ability, and the amount of domestic work they believed was performed by the patient. All ratings were made on seven-point items. Results The results showed that there was no main effect of gender on perceived future work ability of the patient, F (1,131)=0.867, p =0.353. However, male patients were considered to be more accurate in their self-assessed work ability than female patients F (1,131)=5.925 p =0.016 (M female =4.87, SD female =1.22, and M male =5.33, SD male =1.02). Moreover, female patients were thought to perform more domestic work, F (1,131)=25.56, p <0.001 (M female =4.14, SD female =1.41, and M male =3.07, SD male =1.16). Finally, perceived amount of domestic work moderated the effects of perceived future work ability for female but not for male patients, B =0.42, p =0.005. Hence, there was a positive effect of amount of domestic work performed on work ability judgments for women, such that the more domestic work they were assumed to perform, the more they were perceived to be able to work. Conclusions Gender stereotypes influenced assessments of future work ability in pain patients, mainly because women were assumed to perform more domestic work which had a positive effect on perceived work ability. Because domestic work should have a negative effect on recovery, expectations from the physician that domestic work is expected by female patients may in fact have the opposite effect prolonging sick-leave. Moreover, the students trusted the male patients’ ability to assess their own work capacity more than women’s. Implications It is important that medical students receive education about gender biases and how they may influence medical assessment during their training. Such education may alleviate the influence of gender stereotypes.

Background and aims The effect of stretching on joint range of motion is well documented and is primarily related to changes in the tolerance to stretch, but the mechanisms underlying this change are still largely unknown. The aim of this study was to investigate the influence of a remote, painful stimulus on stretch tolerance. Methods Thirty-four healthy male subjects were recruited and randomly assigned to an experimental pain group ( n =17) or a control group ( n =17). Passive knee extension range of motion, the activity of hamstring muscles and passive resistive torque were measured with subjects in a seated position. Three consecutive measures were performed with a 5-min interval between. A static stretch protocol was utilized in both groups to examine the effect of stretching and differences in stretch tolerance between groups. Following this, the pain-group performed a cold pressor test which is known to engage the endogenous pain inhibitory system after which measurements were repeated. Results A significant increase in knee extension range of motion was found in the pain group compared with controls (ANCOVA: p <0.05). No difference was found in muscle activity or passive resistive torque between groups (ANCOVA p >0.091). Conclusions Passive knee extension range of motion following stretching increased when following a distant, painful stimulus, potentially engaging the endogenous pain inhibitory systems. Current findings indicate a link between increased tolerance to stretch and endogenous pain inhibition. Implications The current findings may have implications for clinical practice as they indicate that a distant painful stimulus can influence range of motion in healthy individuals. This implies that the modulation of pain has significance for the efficacy of stretching which is important knowledge when prescribing stretching as part of rehabilitation.

Although fibromyalgia (FM) is now a recognized clinical entity, an early description of this clinical syndrome is found in the Old Testament. In this Letter, biblical passages which are mentioned to the main symptoms of FM (e.g. chronic and disabling pain, unrefreshing sleep and physical exhaustion), actually associated with chronic stress and depression, are presented indicatively.