Innovations and advances in modelling and measuring pain in animals.

Best practices in preclinical algesiometry (pain behaviour testing) have shifted over the past decade as a result of technological advancements, the continued dearth of translational progress and the emphasis that funding institutions and journals have placed on rigour and reproducibility. Here we describe the changing trends in research methods by analysing the methods reported in preclinical pain publications from the past 40 years, with a focus on the last 5 years. We also discuss how the status quo may be hampering translational success. This discussion is centred on four fundamental decisions that apply to every pain behaviour experiment: choice of subject (model organism), choice of assay (pain-inducing injury), laboratory environment and choice of outcome measures. Finally, we discuss how human tissues, which are increasingly accessible, can be used to validate the translatability of targets and mechanisms identified in animal pain models.

Improvement in Health-Related Quality of Life With Spinal Cord Stimulation in Complex Regional Pain Syndrome: A Single-Center, Retrospective Study.

BACKGROUND: Complex regional pain syndrome (CRPS) can profoundly affect many aspects of everyday life. Spinal cord stimulation (SCS) is a potential therapeutic option. This retrospective, single-site evaluation explored health-related quality of life (HRQoL) in individuals with CRPS treated with SCS in our Pain Service. MATERIALS AND METHODS: All patients aged ≥18 years with fully implanted SCS for CRPS between June 2013 and January 2023 were identified from hospital records. The following data were collected: sex, age, chronic pain diagnosis, CRPS type (I or II), location of CRPS (upper or lower limb), years of CRPS before first SCS implant, SCS system, preimplant and follow-up scores for HRQoL (euroqol 5 dimensions 3 levels [EQ-5D-3L] index score), average pain, worst pain and the influence of pain on aspects of everyday life (all numerical rating scale [NRS]), patient and clinician global impression of change at follow-up, and the occurrence and reasons for revisions and explants. An intention-to-treat approach was used and data statistically analyzed. RESULTS: The final cohort comprised 83 patients (46 women), with a median (minimum, maximum) follow-up duration of 29 months (seven, 72). There were statistically and clinically significant improvements in HRQoL, despite relatively low pain response rates. The pain response rate was 34% (reduction of ≥30% in average pain NRS); the pain remission rate was 13% (average pain score ≤3 NRS), and all patients had preimplant EQ-5D-3L index values below the population norm of 0.82. However, 60% of patients reported EQ-5D-3L index scores greater than the published minimally important difference of 0.074, and scores were better at follow-up than at preimplant (p < 0.001); 44% of patients and 41% of clinicians reported improved symptoms at the most recent follow-up. Explants occurred in eight of 83 patients (10%). CONCLUSIONS: Patients had meaningful improvements in HRQoL, which is a key outcome in ascertaining the overall outcome of SCS in CRPS. Randomized controlled clinical trials should build on the findings to improve understanding of the benefits and risks of treating CRPS with SCS.

Multidimensional Perioperative Recovery Trajectories in a Mixed Surgical Cohort: A Longitudinal Cluster Analysis Utilizing National Institutes of Health Patient-Reported Outcome Measurement Information System Measures.

BACKGROUND: Pain trajectories have been described in numerous surgical settings where preoperative characteristics have been used to predict trajectory membership. Suboptimal pain intensity trajectories have been linked to poor longitudinal outcomes. However, numerous biopsychosocial modulators of postoperative pain may also have distinct longitudinal trajectories that may inform additional targets to improve postoperative recovery. METHODS: Patients undergoing total joint arthroplasty, thoracic surgery, spine surgery, major abdominal surgery, or mastectomy completed Patient Reported Outcome Measurement Information System (PROMIS) measures and additional scales preoperatively and at 1 week, 2 weeks, 1 month, 3 months, and 6 months postoperatively. A k-means clustering for longitudinal data was utilized to explore and describe distinct pain impact (PROMIS Pain Interference and Physical Function) trajectories and associated changes in additional biopsychosocial measures. Follow-up analyses examined participant demographics and clinical characteristics associated with trajectory memberships. RESULTS: Three postoperative biopsychosocial symptom clusters were identified across all patients (n = 402): low (35%), average (47%), and high (18%) performance cluster trajectories. Participants undergoing total knee arthroplasty (TKA), spinal surgery, reporting presurgical opioid use, and higher pain catastrophizing scale scores were found to be associated with the low performance trajectory. Patients within the low performance trajectory, while demonstrating small improvements by 6 months, remained mild to moderately impaired in both pain impact and physical health outcomes. Alternatively, participants in the average performance trajectory demonstrated improvement in pain impact to population norms compared to baseline and demonstrated continued improvement across physical and psychological outcomes. Patients within the high performance cluster started within population norms across all measures at baseline and returned to baseline or exceeded baseline values by 6 months postoperatively. Self-reported opioid utilization was significantly higher in the low performance cluster across all time points. While a larger proportion of average performance patients reported opioid utilization during the first postoperative month compared to the high performance cluster, no differences were detected at 6 months postoperatively between these 2 clusters. CONCLUSIONS: These pain impact trajectories build upon previous unidimensional pain intensity trajectories and suggest that additional distinct biopsychosocial measures may have unique trajectories related to cluster assignment. Additionally, these findings highlight the importance of continued pain impact surveillance through the perioperative recovery period to detect patients at risk of experiencing a poor trajectory and subsequently poor longitudinal health outcomes.

Postoperative Pain and Age: A Retrospective Cohort Association Study.

BACKGROUND: As the population ages, the number of elderly people undergoing surgery increases. Literature on the incidence and intensity of postoperative pain in the elderly is conflicting. This study examines associations between age and pain-related patient reported outcomes and perioperative pain management in a dataset of surgical patients undergoing four common surgeries: spinal surgery, hip or knee replacement, or laparoscopic cholecystectomy. Based on the authors' clinical experience, they hypothesize that pain scores are lower in older patients. METHODS: In this retrospective cohort, study data were collected between 2010 and 2018 as part of the international PAIN OUT program. Patients filled out the International Pain Outcomes Questionnaire on postoperative day 1. RESULTS: A total of 11,510 patients from 26 countries, 59% female, with a mean age of 62 yr, underwent one of the aforementioned types of surgery. Large variation was detected within each age group for worst pain, yet for each surgical procedure, mean scores decreased significantly with age (mean Numeric Rating Scale range, 6.3 to 7.3; ß = -0.2 per decade; P ≤ 0.001), representing a decrease of 1.3 Numeric Rating Scale points across a lifespan. The interference of pain with activities in bed, sleep, breathing deeply or coughing, nausea, drowsiness, anxiety, helplessness, opioid administration on the ward, and wish for more pain treatment also decreases with age for two or more of the procedures. Across the procedures, patients reported being in severe pain on postoperative day one 26 to 38% of the time, and pain interfered moderately to severely with movement. CONCLUSIONS: The authors' findings indicate that postoperative pain decreases with increasing age. The change is, however, small and of questionable clinical significance. Additionally, there are still too many patients, at any age, undergoing common surgeries who suffer from moderate to severe pain, which interferes with function, supporting the need for tailoring care to the individual patient.

Procedure-specific acute pain trajectory after elective total hip arthroplasty: systematic review and data synthesis.

BACKGROUND: For most procedures, there is insufficient evidence to guide clinicians in the optimal timing of advanced analgesic methods, which should be based on the expected time course of acute postoperative pain severity and aimed at time points where basic analgesia has proven insufficient. METHODS: We conducted a systematic search of the literature of analgesic trials for total hip arthroplasty (THA), extracting and pooling pain scores across studies, weighted for study size. Patients were grouped according to basic anaesthetic method used (general, spinal), and adjuvant analgesic interventions such as nerve blocks, local infiltration analgesia, and multimodal analgesia. Special consideration was given to high-risk populations such as chronic pain or opioid-dependent patients. RESULTS: We identified and analysed 71 trials with 5973 patients and constructed pain trajectories from the available pain scores. In most patients undergoing THA under general anaesthesia on a basic analgesic regimen, postoperative acute pain recedes to a mild level (<4/10) by 4 h after surgery. We note substantial variability in pain intensity even in patients subjected to similar analgesic regimens. Chronic pain or opioid-dependent patients were most often actively excluded from studies, and never analysed separately. CONCLUSIONS: We have demonstrated that it is feasible to construct procedure-specific pain curves to guide clinicians on the timing of advanced analgesic measures. Acute intense postoperative pain after THA should have resolved by 4-6 h after surgery in most patients. However, there is a substantial gap in knowledge on the management of patients with chronic pain and opioid-dependent patients.

Comparison between epidural and intravenous analgesia effects on disease-free survival after colorectal cancer surgery: a randomised multicentre controlled trial.

BACKGROUND: Thoracic epidural analgesia (TEA) has been suggested to improve survival after curative surgery for colorectal cancer compared with systemic opioid analgesia. The evidence, exclusively based on retrospective studies, is contradictory. METHODS: In this prospective, multicentre study, patients scheduled for elective colorectal cancer surgery between June 2011 and May 2017 were randomised to TEA or patient-controlled i.v. analgesia (PCA) with morphine. The primary endpoint was disease-free survival at 5 yr after surgery. Secondary outcomes were postoperative pain, complications, length of stay (LOS) at the hospital, and first return to intended oncologic therapy (RIOT). RESULTS: We enrolled 221 (110 TEA and 111 PCA) patients in the study, and 180 (89 TEA and 91 PCA) were included in the primary outcome. Disease-free survival at 5 yr was 76% in the TEA group and 69% in the PCA group; unadjusted hazard ratio (HR): 1.31 (95% confidence interval [CI]: 0.74-2.32), P=0.35; adjusted HR: 1.19 (95% CI: 0.61-2.31), P=0.61. Patients in the TEA group had significantly better pain relief during the first 24 h, but not thereafter, in open and minimally invasive procedures. There were no differences in postoperative complications, LOS, or RIOT between the groups. CONCLUSIONS: There was no significant difference between the TEA and PCA groups in disease-free survival at 5 yr in patients undergoing surgery for colorectal cancer. Other than a reduction in postoperative pain during the first 24 h after surgery, no other differences were found between TEA compared with i.v. PCA with morphine.

Factors associated with rebound pain after peripheral nerve block for ambulatory surgery.

BACKGROUND: Rebound pain is a common, yet under-recognised acute increase in pain severity after a peripheral nerve block (PNB) has receded, typically manifesting within 24 h after the block was performed. This retrospective cohort study investigated the incidence and factors associated with rebound pain in patients who received a PNB for ambulatory surgery. METHODS: Ambulatory surgery patients who received a preoperative PNB between March 2017 and February 2019 were included. Rebound pain was defined as the transition from well-controlled pain (numerical rating scale [NRS] ≤3) while the block is working to severe pain (NRS ≥7) within 24 h of block performance. Patient, surgical, and anaesthetic factors were analysed for association with rebound pain by univariate, multivariable, and machine learning methods. RESULTS: Four hundred and eighty-two (49.6%) of 972 included patients experienced rebound pain as per the definition. Multivariable analysis showed that the factors independently associated with rebound pain were younger age (odds ratio [OR] 0.98; 95% confidence interval [CI] 0.97-0.99), female gender (OR 1.52 [1.15-2.02]), surgery involving bone (OR 1.82 [1.38-2.40]), and absence of perioperative i.v. dexamethasone (OR 1.78 [1.12-2.83]). Despite a high incidence of rebound pain, there were high rates of patient satisfaction (83.2%) and return to daily activities (96.5%). CONCLUSIONS: Rebound pain occurred in half of the patients and showed independent associations with age, female gender, bone surgery, and absence of intraoperative use of i.v. dexamethasone. Until further research is available, clinicians should continue to use preventative strategies, especially for patients at higher risk of experiencing rebound pain.

Posterior decompression and fusion versus laminoplasty for cervical ossification of posterior longitudinal ligament: a systematic review and meta-analysis.

Both posterior decompression and fusion (PDF) and laminoplasty (LAMP) have been used to treat cervical myelopathy due to multilevel ossification of posterior longitudinal ligament (OPLL). However, considerable controversy exists over the choice of the two surgical strategies. Thus, the aim of this study is to compare clinical outcomes of PDF and LAMP for treatment of cervical myelopathy due to multilevel OPLL. We searched PubMed, EMBASE and Cochrane Central Register of Controlled Trials database to identify relevant clinical studies compared with clinical outcomes of PDF and LAMP for cervical OPLL. The primary outcomes including Japanese Orthopaedic Association (JOA) score and recovery rate of JOA were evaluated, and the secondary outcomes involving visual analogue scale (VAS), cervical curvature, OPLL progression rate, complication rate, reoperation rate and surgical trauma were also evaluated using Stata software. A total of nine studies were included in the current study, involving 324 patients. The current study suggests that compared with LAMP, PDF achieves a lower OPLL progression rate, better postoperative cervical curvature and similar neurological improvement in the treatment of multilevel cervical OPLL. However, PDF has a higher complication rate, more surgical trauma and higher postoperative VAS than LAMP.

Thirty-five Years of Acute Pain Services: Where Do We Go From Here?

Acute pain services (APS) have developed over the past 35 years. Originally implemented solely to care for patients with regional catheters or patient-controlled analgesia after surgery, APS have become providers of care throughout the perioperative period, with some institutions even taking the additional step toward providing outpatient services for patients with acute pain. Models vary considerably in terms of tasks and responsibilities, staffing, education, protocols, quality, and financing. Many challenges face today's APS, including the increasing number of patients with preexisting chronic pain, intake of analgesics and opioids before surgery, substance-dependent patients needing special care, shorter hospital stays, early discharge of patients in need of further analgesic treatment, prevention and treatment of chronic postsurgical pain, minimization of adverse events, and side effects of treatment. However, many APS lack a clear-cut definition of their structures, tasks, and quality. Development of APS in the future will require us to face urgent questions, such as, "What are meaningful outcome variables?" and, "How do we define high quality?" It is obvious that focusing exclusively on pain scores does not reflect the complexity of pain and recovery. A broader approach is needed-a common concept of surgical and anesthesiological services within a hospital (eg, procedure-specific patient pathways as indicated by the programs "enhanced recovery after surgery" or the "perioperative surgical home"), with patient-reported outcome measures as one central quality criterion. Pain-related functional impairment, treatment-induced side effects, speed of mobilization, as well as return to normal function and everyday activities are key.

A registry based analysis of the patient reported outcome after surgery for trapeziometacarpal joint osteoarthritis.

BACKGROUND: The aim of the study was to evaluate patient reported outcome measures (PROM) before and after trapeziectomy with or without ligament reconstruction and tendon interposition for trapeziometacarpal joint arthritis with special focus on possible differences due to gender, age and surgical method. METHODS: Data from the Swedish quality registry for hand surgery (HAKIR) was analyzed preoperatively, 3 months and 1 year postoperatively for 1850 patients (mean age 63 years, 79% women). RESULTS: One year postoperatively, mean pain at rest was reduced from 50 to 12 of maximum 100. However, pain on load and weakness had not abated to the same extent (mean 30 and 34 of 100, respectively). The mean improvement in PROM did not differ between age groups or gender. The result was similar after trapeziectomy with ligament reconstruction and tendon interposition (86% of the patients) and simple trapeziectomy but few patients were operated with the latter method. CONCLUSION: Pain on load and weakness remains to some extent 1 year after surgery for trapeziometacarpal joint arthritis. The result is similar after trapeziectomy with or without ligament reconstruction and tendon interposition and the same improvement can be expected after surgery regardless of age and gender.

The association between believing staying active is beneficial and achieving a clinically relevant functional improvement after 52 weeks: a prospective cohort study of patients with chronic low back pain in secondary care.

BACKGROUND: According to clinical guidelines, advice to stay active despite experiencing pain is recommended to patients with non-specific low back pain (LBP). However, not all patients receive guideline-concordant information and advice, and some patients still believe that activity avoidance will help them recover. The purpose was to study whether guideline-concordant beliefs among patients and other explanatory variables were associated with recovery. The main aim was to investigate whether believing staying active despite having pain is associated with a better functional outcome. METHODS: This was a prospective cohort study involving adults with non-specific LBP referred from general practices to the Spine Centre at Silkeborg Regional Hospital, Denmark. Patients reported on their beliefs about the importance of finding the cause, the importance of diagnostic imaging, perceiving to have received advice to stay active, pain duration, pain intensity, and STarT Back Tool. Agreeing to: 'An increase in pain is an indication that I should stop what I'm doing until the pain decreases' adjusted for age, gender, and education level was the primary explanatory analysis. A 30% improvement in the Roland Morris Disability Questionnaire (RMDQ) score after 52 weeks was the outcome. RESULTS: 816 patients were included and 596 (73.0%) agreed that pain is a warning signal to stop being active. Among patients not considering pain as a warning signal, 80 (43.2%) had a favourable functional improvement of ≥30% on the RMDQ compared to 201 (41.2%) among patients considering pain a warning signal. No difference was found between the two groups (adjusted P = 0.542 and unadjusted P = 0.629). However, STarT Back Tool high-risk patients had a less favourable functional outcome (adjusted P = 0.003 and unadjusted P = 0.002). Chronic pain was associated with less favourable functional outcome (adjusted P < 0.001 and unadjusted P < 0.001), whereas beliefs about finding the cause, diagnostic imaging, perceiving to have received advice to stay active, or pain intensity were not significantly associated with outcome. CONCLUSIONS: Holding the single belief that pain is a warning signal to stop being active was not associated with functional outcome. However, patients characterised by having multiple psychological barriers (high-risk according to the STarT Back Tool) had a less favourable functional outcome. TRIAL REGISTRATION: Registered at ClinicalTrials.gov (registration number: NCT03058315), 20 February 2017.

Back pain outcomes after minimally invasive anterior lumbar interbody fusion: a systematic review.

OBJECTIVE: Minimally invasive anterior lumbar interbody fusion surgery (MIS ALIF) is a technique that restores disc height and lumbar lordosis through a smaller exposure and less soft-tissue trauma compared to open approaches. The mini-open and laparoscopic assistance techniques are two main forms of MIS ALIF. The authors conducted a systematic review that sought to critically summarize the literature on back pain following MIS ALIF. METHODS: In March 2020, the authors searched the PubMed, Web of Science, and Cochrane Library databases for studies describing back pain visual analog scale (VAS) outcomes after MIS ALIF. The following exclusion criteria were applied to studies evaluated in full text: 1) the study included fewer than 20 patients, 2) the mean follow-up duration was shorter than 12 months, 3) the study did not report back pain VAS score as an outcome measure, and 4) MIS ALIF was not studied specifically. The methodology for the included studies were evaluated for potential biases and assigned a level of evidence. RESULTS: There were a total of 552 patients included from 13 studies. The most common biases were selection and interviewer bias. The majority of studies were retrospective. The mean sample size was 42.3 patients. The mean follow-up duration was approximately 41.8 months. The mean postoperative VAS reduction was 5.1 points. The mean VAS reduction for standalone grafts was 5.9 points, and 5.0 points for those augmented with posterior fixation. The most common complications included bladder or urinary dysfunction, infection, and hardware-related complications. CONCLUSIONS: This was a systematic review of back pain outcomes following MIS ALIF. Back pain VAS score was reduced postoperatively across all studies. The complication rates were low overall. MIS ALIF is safe and effective at reducing back pain in appropriate patient populations.

A Retrospective Review of School Nurse Approaches to Assessing Pain.

BACKGROUND: When students with intellectual disability (ID) experience pain, the pain may limit the extent to which they may engage in school activities. Although school nurses are primarily responsible for addressing students' pain, there are many barriers to identifying pain in students with ID. AIMS: The purpose of the present study was to describe pain assessment practices of school nurses for students with and without ID. DESIGN: A retrospective review was conducted of 4,660 school health office visit records for elementary school students presenting to the health office with headache, stomachache, or sore throat. METHODS: Data were extracted and transcribed to a matrix. Data extracted included school grade, referral source, visit month, gender, cognitive ability, chief concern, pain assessment, external contact, and disposition. Descriptive statistics were calculated. RESULTS: School nurses spent more time on average addressing pain in neurotypical students than in students with ID. Neurotypical students more often presented with a teacher and were dismissed from school, but parents and guardians were contacted less often for these students, when compared to students with ID. Quantified pain ratings were documented for 1% of visits. CONCLUSIONS: Because pain intensity ratings were rarely documented, the utility of such ratings in the school setting may be low. Alternatively, obtaining pain intensity ratings from younger children may be challenging without the use of appropriate tools. Nurses, teachers, and other staff providing education and care to students with ID may require pain training. Implementation of tools that elicit student pain information from parents/guardians in the school setting could decrease point-of-care contact during the school day and proactively provide information on unique child pain behaviors.

High-Dose Spinal Cord Stimulation for Treatment of Chronic Low Back Pain and Leg Pain in Patients With FBSS, 12-Month Results: A Prospective Pilot Study.

OBJECTIVES: To investigate the long-term effect of high-dose spinal cord stimulation (HD-SCS) in patients with chronic refractory low back and leg pain due to failed back surgery syndrome (FBSS). STUDY DESIGN: Prospective case series; pilot study. MATERIALS AND METHODS: Patients with chronic low back and leg pain (CBLP) due to failed back surgery syndrome (FBSS) were screened for SCS according to the Dutch Neuromodulation Society guidelines. Patients with a pain score of >50 (on a visual analogue scale from 0 to 100) for both low back and leg pain, were selected for participation in this study. During intraoperative screening one or two electrodes were implanted to ensure adequate paresthesia coverage of the back and leg pain area. During the 14 days trial period patients received two programs: a conventional or low-dose (LD) program with 30 Hz; 390 µsec and a high-dose (HD) program with 420 Hz, 400 µsec. They all started with LD-SCS and changed to HD-SCS after three days. If patients reported more than 50% pain relief with either program a rechargeable neurostimulator was implanted for permanent SCS. The scores for low back pain and leg pain were recorded separately. Other therapy related outcomes that were collected are pain medication use, Quebec back pain disability scale (QBPDS), patient satisfaction, employment status, stimulation settings, and adverse events. We present the 6- and 12-months results. Results are presented as mean ± SD. RESULTS: Thirteen patients, nine females and four males (mean age: 49.7 ± 8.1 years), were included between July 2015 and March 2016. Eleven patients responded to SCS during the trial period and were implanted with a neurostimulator. Most patients preferred HD-SCS over LD-SCS and the overall use of HD-SCS increased over time. At 6 to 12 months follow-up, two patients discontinued the study. In one patient low back pain returned despite optimal stimulation settings. The second patient was neither satisfied with LD nor HD and had the system explanted. VAS Leg pain at baseline was 71.2 ± 33.8 and reduced to 25.7 ± 24.0 at 6 months and 23.4 ± 32.0 at 12 months. VAS Back pain at baseline was 66.7 ± 33.2 and reduced to 36.8 ± 41.6 at 6 months and 26.1 ± 33.2 at 12 months. Pain medication was significantly reduced and QBPDS improved from 59.2 ± 12.2 at baseline to 44.1 ± 13.7 at 12 months. Five patients returned to work and overall patient satisfaction at the end of the study was high. CONCLUSION: This pilot study shows promising results of offering HD-SCS in addition to LD-SCS for treatment of chronic back and leg pain in patients with failed back surgery syndrome.

Predictors of Reduced Opioid Use With Spinal Cord Stimulation in Patients With Chronic Opioid Use.

OBJECTIVES: Spinal cord stimulation (SCS) has gained traction as an alternative to chronic opioid therapy in light of the opioid crisis. Prior reports vary widely in their estimates of its effect on opioid consumption. We therefore aimed to address the following questions: 1) Does chronic opioid use change after SCS? 2) Which patient characteristics predict reduced opioid consumption after SCS? MATERIALS AND METHODS: Claims from a private health insurance company were used to identify patients with SCS implantation from 2003 to 2014. We required 12 months of continuous data before and after surgery (i.e., a minimum total observation period of two years), and at least two opioid prescription fills in the six months before surgery. Daily morphine equivalent dose (MED) was calculated from prescription medication claims. Diagnosis codes identified common comorbidities. RESULTS: Hundred forty-five patients met inclusion criteria. MED of 65 was the most statistically meaningful preoperative dose threshold. Approximately half of patients decreased opioid use >20% after SCS implantation. Logistic regression analysis revealed age (p = 0.0362), gender (p = 0.0076), and preoperative daily MED < 65 (p = 0.0322) as predictors of meaningful reduction, which was defined as a 20% reduction in MED. CONCLUSIONS: With only half of chronic opioid users demonstrating meaningful opioid reduction after SCS implantation, we demonstrate that current SCS technology does not reliably help a larger number of patients reduce opioid usage. Women, older age, and preoperative MED < 65 are predictive of meaningful opioid reduction but only one of these is modifiable. As not all patients saw benefit from their therapies, there is still much room for improvement in the treatment of refractory chronic pain that is associated with failed back surgery syndrome and chronic regional pain syndrome.

Update on structured pain assessment for the documentation of diagnosis-independent symptoms and signs associated with pain.

Concerning the diagnosis and therapy of pain syndromes, standardized descriptions similar to those used in the examination of psychopathological findings via the system produced by the AMDP ("Arbeitsgemeinschaft für Methodik und Dokumentation in der Psychiatrie", i. e., the working group establishing standardized methodology and documentation within psychiatry) are still lacking. Therefore, the authors of this article have founded a working group to establish standardized methodology and documentation for symptoms and signs associated with pain, although not at a diagnosis-specific level, in order to promote standardization in the documentation of pain and rating of the symptoms associated with a given set of medical results. This article presents a system for documenting the symptoms and signs associated with pain globally and independently of the diagnosis (Structured Pain Assessment System) with nomenclature that is inspired by the AMDP system. The objective of this working group is to develop documentation for a uniform multidimensional pain assessment (with defined terminology) that serves as a comparable and unified standard in the field.

Increased cerebral responses to salient transitions between alternating stimuli in chronic migraine with medication overuse headache and during migraine attacks.

INTRODUCTION: In a previous study exploring central pain modulation with heterotopic stimuli in healthy volunteers, we found that transitions between sustained noxious and innocuous thermal stimulations on the foot activated the "salience matrix". Knowing that central sensory processing is abnormal in migraine, we searched in the present study for possible abnormalities of these salient transitional responses in different forms of migraine and at different time points of the migraine cycle. METHODS: Participants of both sexes, mostly females, took part in a conditioned pain modulation experiment: Migraineurs between (n = 14) and during attacks (n = 5), chronic migraine patients with medication overuse headache (n = 7) and healthy volunteers (n = 24). To evoke the salience response, continuous noxious cold or innocuous warm stimulations were alternatively applied on the right foot. Cerebral blood oxygenation level dependent responses were recorded with fMRI. RESULTS: Switching between the two stimulations caused a significant transition response in the "salience matrix" in all subject groups (effect of the condition). Moreover, some group effects appeared on subsequent post-hoc analyses. Augmented transitional blood oxygenation level dependent responses in the motor cortex and superior temporal sulcus were found in two patient groups compared to healthy controls: chronic migraine with medication overuse headache patients and migraineurs recorded during an attack. In chronic migraine with medication overuse headache patients, salience-related responses were moreover greater in the premotor cortex, supplementary motor area, lingual gyrus and dorso-medial prefrontal cortex and other "salience matrix" areas, such as the anterior cingulate and primary somatosensory cortices. CONCLUSION: This study shows salience-related hyperactivation of affective and motor control areas in chronic migraine with medication overuse headache patients and, to a lesser extent, in episodic migraine patients during an attack. The greater extension of exaggerated blood oxygenation level dependent responses to unspecific salient stimuli in chronic migraine with medication overuse headache than during a migraine attack could be relevant for headache chronification.

Acute Pain Resolution After an Emergency Department Visit: A 14-Day Trajectory Analysis.

STUDY OBJECTIVE: The objective of the study is to evaluate the acute pain intensity evolution in emergency department (ED) discharged patients, using group-based trajectory modeling. This method identifies patient groups with similar profiles of change over time without assuming the existence of a particular pattern or number of groups. METHODS: This was a prospective cohort study of ED patients aged 18 years or older, with an acute pain condition (≤2 weeks), and discharged with an opioid prescription. Patients completed a 14-day diary assessing daily pain intensity level (numeric rating scale of 0 to 10) and pain medication use. RESULTS: Among the 372 included patients, 6 distinct post-ED pain intensity trajectories were identified. Two started with severe levels of pain; one remained with severe pain intensity (12.6% of the sample) and the other ended with a moderate pain intensity level (26.3%). Two other trajectories had severe initial pain; one decreased to mild pain (21.7%) and the other to no pain (13.8%). Another trajectory had moderate initial pain that decreased to a mild level (15.9%) and the last one started with mild pain intensity and had no pain at the end of the 14-day period (9.7%). The pain trajectory patterns were significantly associated with age, type of painful conditions, pain intensity at ED discharge, and opioid consumption. CONCLUSION: Acute pain resolution after an ED visit seems to progress through 6 different trajectory patterns that are more informative than simple linear models and could be useful to adapt acute pain management in future research.

Developing a Pain Intensity Measure for Persons with Dementia: Initial Construction and Testing.

OBJECTIVE: The goal of this study was to identify a limited set of pain indicators that were most predicive of physical pain. We began with 140 items culled from existing pain observation tools and used a modified Delphi approach followed by statistical analyses to reduce the item pool. METHODS: Through the Delphi Method, we created a candidate item set of behavioral indicators. Next, trained staff observed nursing home residents and rated the items on scales of behavior intensity and frequency. We evaluated associations among the items and expert clinicians' assessment of pain intensity. SETTING: Four government-owned nursing homes and 12 community nursing homes in Alabama and Southeastern Pennsylvania. PARTICIPANTS: Ninety-five residents (mean age = 84.9 years) with moderate to severe cognitive impairment. RESULTS: Using the least absolute shrinkage and selection operator model, we identified seven items that best predicted clinicians' evaluations of pain intensity. These items were rigid/stiff body or body parts, bracing, complaining, expressive eyes, grimacing, frowning, and sighing. We also found that a model based on ratings of frequency of behaviors did not have better predictive ability than a model based on ratings of intensity of behaviors. CONCLUSIONS: We used two complementary approaches-expert opinion and statistical analysis-to reduce a large pool of behavioral indicators to a parsimonious set of items to predict pain intensity in persons with dementia. Future studies are needed to examine the psychometric properties of this scale, which is called the Pain Intensity Measure for Persons with Dementia.