Pain Perception Research Articles

Real-time monitoring of cortical brain activity in response to acute pain using wide-area Ca2+ imaging

Previous human and rodent studies indicated that nociceptive stimuli activate many brain regions that is involved in the somatosensory and emotional sensation. Although these studies have identified several important brain regions involved in pain perception, it has been a challenge to observe neural activity directly and simultaneously in these multiple brain regions during pain perception. Using a transgenic mouse expressing G-CaMP7 in majority of astrocytes and a subpopulation of excitatory neurons, we recorded the brain activity in the mouse cerebral cortex during acute pain stimulation. Both of hind paw pinch and intraplantar administration of formalin caused strong transient increase of the fluorescence in several cortical regions, including primary somatosensory, motor and retrosplenial cortex. This increase of the fluorescence intensity was attenuated by the pretreatment with morphine. The present study provides important insight into the cortico-cortical network during pain perception.

Pain Perception Following Periodontal Decontamination Treatment with Laser Therapies: Comparison between Oxygen High-Level Laser Therapy (OHLLT) and Laser-Assisted New Attachment Procedure (LANAP)

Introduction: Within the field of periodontology, there has been a proposal for the utilization of noninvasive laser therapy as a potential treatment for persistent periodontitis. The Laser-Assisted New Attachment Procedure (LANAP) employs an Nd:YAG laser as a specific technique. Through its interaction with endogenous chromophores, the Nd: YAG laser exhibits a selective effect on the evaporation of granulation tissue, therefore establishing a correlation with reduced bleeding. The study also examined Oxygen High-Level Laser Therapy (OHLLT). The OHLLT technique employs a high-power diode laser in combination with hydrogen peroxide solutions to facilitate the liberation of singlet oxygen, which possesses antibacterial attributes, within the periodontal pockets. The existing literature indicates their potential to promote the regeneration of tooth support tissues. Objective: The aim of this study is to assess the subjective pain levels reported by patients who have undergone surgery using the OHLLT protocol versus those who have undergone surgery using the LANAP technique. Methods: A total of 20 individuals with a stage III–IV periodontitis diagnosis were recruited for the study. The participants were randomly divided into two groups, each consisting of 10 individuals: Group 1, comprising patients treated according to the LANAP protocol, and Group 2, comprising patients treated according to the OHLLT protocol. After their initial session of nonsurgical periodontal therapy, individuals provided feedback regarding their level of pain, utilizing a Numerical Rating Scale (NRS) comprising time intervals of 0 h (T0), 6 h (T1), 12 h (T2), 24 h (T3), 48 h (T4), and 7 days (T5). The Wilcoxon–Mann–Whitney statistical test was employed to assess the variations in NRS scores between Group 1 and Group 2 at each recording period. (p ≤ 0.05). In addition, a microbiological assessment of the bacterial load in the periodontal region was conducted on all subjects using real-time PCR testing at two time points: prior to treatment (T0) and seven days post-treatment (T5). Results: The findings of this study indicate that the OHLLT group exhibited significantly lower pain levels compared to the LANAP group at all time intervals, except for the preoperative period, where no significant difference was observed (p < 0.05). Group 2 exhibited a more rapid decrease in pain, as demonstrated by a score test approaching zero within 24 h. The quantity of periodontal bacteria seen seven days post-treatment was similar between the two groups and was found to be decreased compared to the pre-treatment levels. Conclusions: The OHLLT and LANAP regimens have demonstrated efficacy in the nonsurgical management of periodontal disease. Nevertheless, it should be noted that the OHLLT approach does not subject the patient to any thermal hazards, unlike the LANAP method. The postoperative discomfort experienced following the OHLLT procedure is indeed reduced, as this technique is characterized by lower invasiveness and reduced dependence on the operator.

Framework for Personalized Chronic Pain Management: Harnessing AI and Personality Insights for Effective Care

This paper introduces a cutting-edge framework for personalized chronic pain management, leveraging the power of artificial intelligence (AI) and personality insights. It explores the intricate relationship between personality traits and pain perception, expression, and management, identifying key correlations that influence an individual's experience of pain. By integrating personality psychology with AI-driven personality assessment, this framework offers a novel approach to tailoring chronic pain management strategies for each patient's unique personality profile. It highlights the relevance of well-established personality theories such as the Big Five and the Myers-Briggs Type Indicator (MBTI) in shaping personalized pain management plans. Additionally, the paper introduces multimodal AI-driven personality assessment, emphasizing the ethical considerations and data collection processes necessary for its implementation. Through illustrative case studies, the paper exemplifies how this framework can lead to more effective and patient-centered pain relief, ultimately enhancing overall well-being. In conclusion, the paper positions the need of an "AI-Powered Holistic Pain Management Initiative" which has the potential to transform chronic pain management by providing personalized, data-driven solutions and create a multifaceted research impact influencing clinical practice, patient outcomes, healthcare policy, and the broader scientific community's understanding of personalized medicine and AI-driven interventions.

Pain and its Perceived Relatedness to the Onset, Maintenance, and Relapse of Opioid use Disorder: A Descriptive Study of Non-Treatment-Seeking Individuals

ABSTRACT Background Previous research has found chronic pain to be prevalent among individuals with opioid use disorder (OUD). The perception that pain is related to OUD onset, maintenance, relapse, and treatment delay has been noted in this population. However, prior works primarily involved treatment-engaged populations. Scant research describes such perceptions among non-treatment-seeking individuals. Aims This study describes pain burden and perceptions regarding the role of pain in OUD onset, maintenance, relapse, and addiction treatment delay in a sample of individuals with untreated OUD. Methods This cross-sectional study surveyed syringe exchange participants (n = 141). Participants responded to a survey including Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition OUD criteria, pain survey scales, demographic characteristics, and questions regarding pain and its perceived relatedness to aspects of OUD. Results Most participants reported pain within the past 4 weeks (127, 91.4%). Data displayed a skew toward more intense pain ratings, with 120 reporting their pain as greater than mild (86.3%). A majority of participants agreed that pain was responsible for their OUD onset (79, 56.4%), maintenance (76, 54.3%), past relapse experience (82, 57.9%), and treatment delay (81, 57.9%). Correlative analyses revealed that pain severity and interference measures displayed moderate and statistically significant associations with extent of perceived relatedness of pain to these aspects of OUD. Conclusions Among this sample of individuals with untreated OUD, pain and pain interference were prevalent. Pain was perceived to be related to OUD onset, maintenance, relapse, and treatment delay by a majority of the sample. These findings are in accordance with and expand upon prior works. Abbreviations OUD: opioid use disorder; DSM-5: Diagnostic and Statistical Manual 5; BPI: Brief Pain Inventory; NIDA: National Institute on Drug Abuse; IASP: International Association for the Study of Pain; MOUD: Medications for Opioid Use Disorder; IQR: Interquartile Range.

CROSS-CULTURAL PERSPECTIVES ON PAIN: A COMPREHENSIVE REVIEW OF ANTHROPOLOGICAL RESEARCH

Cross-cultural perspectives on pain offer valuable insights into how different societies understand, experience, and manage pain. This comprehensive review of anthropological research explores the diverse cultural beliefs, practices, and experiences related to pain. It highlights the importance of considering cultural context in understanding pain perception and management. Anthropological research has revealed that pain is not solely a physiological phenomenon but is deeply intertwined with cultural beliefs, social norms, and individual experiences. Different cultures may have varying concepts of pain, with some viewing it as a natural part of life, while others see it as a punishment or a test of endurance. These cultural beliefs can influence how pain is expressed, perceived, and treated within a society. The review examines how cultural factors shape pain communication and expression. For example, some cultures may encourage stoicism and discourage the open expression of pain, while others may view pain expression as a way to seek sympathy and support. These cultural norms can impact how individuals seek help for their pain and how they interact with healthcare providers. Furthermore, the review explores cultural variations in pain management strategies. While some cultures may rely heavily on traditional healing practices such as herbal remedies or spiritual rituals, others may prioritize biomedical interventions. Understanding these cultural differences is essential for healthcare providers to provide culturally sensitive care and improve patient outcomes. Overall, this review underscores the importance of taking a holistic and culturally informed approach to pain management. By recognizing and respecting cultural differences in the experience and expression of pain, healthcare providers can deliver more effective and compassionate care to individuals from diverse cultural backgrounds.
 Keywords: Cross-Cultural, Perspective, Pain, Anthropological, Research.

The relationship between pregnancy and temporomandibular disorder (TMD) through diagnostic criteria for temporomandibular disorders (DC/TMD) axis II evaluation: a case-control cross-sectional study

IntroductionThis study focuses on temporomandibular disorders (TMDs), which affect the temporomandibular joint and related muscles and have multiple causes. Recent studies have examined the connection between menstrual cycles, estrogen levels, and TMDs, but results are inconsistent, highlighting the need for more research. The aim is to explore the prevalence of TMDs in pregnant women and consider how hormonal changes during pregnancy might influence these disorders.MethodsIn this cross-sectional case-control study, we compared 32 pregnant women with 35 non-pregnant women. We evaluated several TMD-related factors such as pain levels, chronic pain classification, scores on the Jaw Functional Limitation Scale-20 and Oral Behaviors Checklist, and psychological health. We used various statistical methods including descriptive statistics, chi-square tests, linear regression, and adjustments for multiple comparisons to analyze the data.ResultsPregnant women showed different pain perceptions, generally reporting less pain and lower severity. Nonetheless, these differences were not uniform across all TMD-related measures. Linear regression did not find a consistent link between pregnancy and TMD scores, except for chronic pain grade, which was not significant after adjusting for multiple comparisons. There was a significant relationship between depression and TMD severity, emphasizing the need to consider mental health in TMD evaluations.DiscussionThe findings suggest that pregnancy is neither a risk nor a protective factor for TMD. Differences in pain perception, functional status, and psychological health were observed in pregnant women but were not consistent for all TMD-related aspects. The role of estrogen in TMJ health and TMD risk is complex and requires further study. The research highlights the necessity of including mental health, especially depression, in TMD assessments. More comprehensive research with larger sample sizes is essential to better understand the connections between pregnancy, TMD, and hormones, aiming to improve TMD management in pregnant women and others.

Therapeutic potential of vitamin supplements in dry eye disease: A comprehensive review

Dry eye disease (DED) stands as a widespread global health issue that impacts people's quality of life, productivity at work, and financial stability significantly. It is identified by either a decrease in tear production, heightened evaporation of tears, or the presence of low-quality tears. These factors collectively contribute to inflammation, damage to the surface of the eye, and unusual perception of pain. The development of DED involving instability in the tear film, increased tear fluid concentration (hyperosmolarity), and inflammation. This cycle tends to sustain itself. Conventional treatments like artificial tear replacements and corticosteroids have proven to be ineffective in addressing this condition. Alongside conventional anti-inflammatory medications, nutrients that possess both anti-inflammatory and antioxidant properties have gained attention as potential DED treatments. Emerging data shows a connection between vitamin deficiencies and a significant DED risk, highlighting the role of vitamins in ocular health. Evidence supports that vitamins may interrupt the vicious cycle of DED pathogenesis and ameliorate inflammation. The review explores the efficacy of vitamins like vitamin A, vitamin D, vitamin C, and vitamin E in mitigating the Complications of DED. The findings suggest that vitamin supplementation holds promise as a complementary approach to managing DED.

A Comparative Evaluation of Pain Experience and Time of Onset of 2% Lignocaine and 4% Articaine in Inferior Alveolar Nerve Block among Pediatric Population: A Clinical Study.

The objective of this research was to conduct a comparison and evaluate the pain perception and time of onset of 2% lignocaine 1:80,000 epinephrine with 4% articaine 1:100,000 epinephrine in the pediatric population. A split-mouth randomized control trial was conducted on 50 children aged 9-14 years who required inferior alveolar nerve block (IANB) anesthesia for bilateral dental treatment in the mandibular arch. The time of onset was recorded when no sensation was reported even when maximum electrical stimulus was applied in an electric pulp testing (EPT). The pain perception was assessed using a visual analog scale (VAS) rated by the patient for subjective symptoms and face, legs, activity, cry, and consolability (FLACC) scale for objective pain rated by the operator. The mean onset of time, pain-VAS, and FLACC score decreased by 1.31, 12.07, and 18.39%, respectively in 4% articaine as compared to 2% lignocaine but the difference did not reach statistical significance (p > 0.05), that is, found to be statistically the same.In conclusion, it can be inferred that the utilization of 4% articaine is as potent as 2% lignocaine solution but showed slightly better onset of anesthesia and pain experience among the children although the findings were not statistically significant. Local anesthesia (LA) is one of the main methods of pain management in pediatric practice which makes it essential to choose an LA agent with a shorter time of onset and less pain on administration. Singh SS, Koul M. A Comparative Evaluation of Pain Experience and Time of Onset of 2% Lignocaine and 4% Articaine in Inferior Alveolar Nerve Block among Pediatric Population: A Clinical Study. Int J Clin Pediatr Dent 2024;17(1):67-71.

Testing Biological and Psychological Pathways of Emotion Regulation as a Primary Mechanism of Action in Yoga Interventions for Chronic Low Back Pain: Protocol for a Randomized Controlled Trial.

Interventions that promote adaptive emotion regulation (ER) skills reduce pain in patients with chronic pain; however, whether the effects of yoga practice on chronic low back pain (CLBP) are due to improvements in ER remains to be examined. This study will test whether the effects of yoga on CLBP (improved pain severity and interference) are mediated by improved ER, the extent to which effects are related to specific aspects of ER, and the role of pain sensitization as a mediator or moderator of effects. In this study, pain sensitization will be assessed by quantitative sensory testing and gene expression profiles to examine whether pain sensitization moderates yoga's effects on pain or whether yoga and ER abilities reduce pain sensitization, leading to decreased pain severity and interference. For this 2-arm parallel group blinded randomized controlled trial, we will enroll 204 adults with CLBP who will be randomized to receive the yoga (n=102) or a control stretching and strengthening (n=102) intervention, which are delivered via web-based synchronous biweekly 75-minute sessions over 12 weeks. Participants are encouraged to practice postures or exercises for 25 minutes on other days using accessible prerecorded practice videos that are sent to participants digitally. Participants will be assessed at 5 time points: baseline, midintervention (6 weeks), postintervention (12 weeks), and 3- and 6-month follow-ups. Assessments of ER, pain severity and interference, pain sensitivity including somatosensory and gene expression profiles, and physical strength and flexibility will be conducted at each visit. The fidelity of the interventions is assessed using a manualized checklist to evaluate recorded group sessions to ensure consistent instructor delivery. The primary outcome will be the mean change in pain severity as measured by the Brief Pain Inventory-Short Form at 12 weeks. The primary mechanism of action is ER measured by change in the Difficulties in Emotion Regulation Scale total score. Secondary outcomes include pain sensitivity, physical strength and flexibility, pain interference, and quality of life. A mediation path analysis and series of moderated mediation path analyses will be conducted to test the study hypotheses. As of January 2024, we have enrolled 138 participants. We expect the study to be completed by May 2025. The study will provide important data for evaluating whether improvements in ER are responsible for reduced pain perception and pain sensitivity as well as increased quality of life in the context of chronic pain. The study findings have important implications for determining the mechanism of action for yoga and possibly other mind-body interventions as nonpharmacological therapies for pain management. The results of the study will inform the content, delivery, and measures for intervention trials involving yoga as a modality for relieving pain and improving function. ClinicalTrials.gov NCT04678297; https://clinicaltrials.gov/study/NCT04678297. DERR1-10.2196/56016.

Hypnosis as an approach to control pain and anxiety in knee pain: A multiple case report

This scientific study explores the efficacy of hypnosis as a therapeutic intervention for managing both pain and anxiety associated with knee pain. The research adopts a multiple case study design, investigating the experiences of individuals suffering from knee pain who underwent hypnosis sessions. The study aims to assess the impact of hypnosis on pain perception, anxiety levels, and overall quality of life in a diverse sample of participants. Methodological rigor is maintained through the use of standardized pain and anxiety assessment tools, longitudinal data collection, and qualitative interviews. Preliminary findings indicate a promising reduction in both pain and anxiety, suggesting the potential of hypnosis as a complementary approach in the multidimensional management of knee pain. The implications of these results for clinical practice and future research avenues are discussed, emphasizing the need for further exploration of hypnosis as a viable therapeutic option in pain and anxiety management.

Efficacy of ShotBlocker device versus vapocoolant spray for spinal needle pain relief during spinal anaesthesia in elective caesarean section - A randomised controlled trial.

Apprehension of pain due to a spinal needle is often a cause of anxiety and refusal. ShotBlocker provides non-painful physical stimulation, inhibiting pain perception. The vapocoolant spray contains ethyl chloride vapours, rapidly raising the skin temperature and hampering the transmission of noxious stimuli. The present study compared the effectiveness of the ShotBlocker device and the vapocoolant spray in reducing spinal needle-associated pain in primigravida women undergoing elective lower-segment caesarean section (LSCS). We enroled 144 primigravida women undergoing elective LSCS and were randomised to Group SB (the ShotBlocker device was firmly pressed over the skin, and the spinal needle was inserted through its slit), Group V (the vapocoolant spray was applied at the puncture site before spinal needle insertion), and Group C (received local infiltration before spinal anaesthesia (SA)). The groups were compared for needle-associated pain and patient satisfaction using a 10-point visual analogue scale (VAS) and a 3-point Likert scale. The mean (standard deviation) [95% confidence interval (CI)] VAS scores of Group SB 3.85 (0.74) [3.64, 4.07] and Group V 3.04 (0.74) [2.83, 3.26] were significantly lower than that of Group C 5.19 (0.92) [3.28, 3.62]). On the Likert scale, the maximum number of patients in the vapocoolant group (64.6%) responded satisfactorily, while in the control group, the majority (62.5%) of participants responded dissatisfied (P < 0.001). Both the ShotBlocker and vapocoolant spray reduce needle puncture-associated pain before SA in primigravida patients undergoing elective LSCS. However, the vapocoolant spray is more beneficial in reducing spinal needle-associated pain than the ShotBlocker device.

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Effects of transcutaneous auricular vagus nerve stimulation at left cymba concha on experimental pain as assessed with the nociceptive withdrawal reflex, and correlation with parasympathetic activity.

The aim of this study was to clarify the effects of transcutaneous auricular vagus nerve stimulation (taVNS) to the left cymba concha on the pain perception using nociceptive withdrawal reflex (NWR), which is known to be associated with chronic pain, and to investigate whether there is a relationship between taVNS-induced suppression of the NWR and parasympathetic activation. We applied either 3.0mA, 100 Hz taVNS for 120 s on the left cymba concha (taVNS condition) or the left earlobe (Sham condition) for 20 healthy adults. NWR threshold was measured before (Baseline), immediately after (Post 0), 10min (Post 10) and 30 min after (Post 30) stimulation. The NWR threshold was obtained from biceps femoris muscle by applying electrical stimulation to the sural nerve. During taVNS, electrocardiogram was recorded, and changes in autonomic nervous activity measured by heart rate variability (HRV) were analyzed. We found that the NWR thresholds at Post 10 and Post 30 increased compared with baseline in the taVNS group (10min after: p = .008, 30 min after: p = .008). In addition, increased parasympathetic activity by taVNS correlated with a greater increase in NWR threshold at Post 10 and Post 30 (Post 10: p = .003; Post 30: p = .001). The present results of this single-blinded study demonstrate the pain-suppressing effect of taVNS on NWR threshold and suggest that the degree of parasympathetic activation during taVNS may predict the pain-suppressing effect of taVNS after its application.

Designing and clinical application of caps for intramedullary pinning to manage long bone fracture in dogs

Study was carried out to design and evaluate clinical application of caps for intramedullary pinning to mange long bone fractures in dogs. Cannulated cancellous caps made of 316 L stainless steel with dimensions of 10 mm × 25 mm (length) cap for 4 mm, 4.5 mm and 5 mm steinmann pin and 8 mm × 25 mm (length) cap for 2.5 mm and 3 mm steinmann pin were designed. A total of 14 cases of dogs presented with simple transverse, short oblique fractures of long bones were equally divided into groups A and B having 7 animals in each. Simple intramedullary pinning was done in group A, whereas, in group B designed caps were fixed at entry point at trochanteric fossa after intramedullary pinning to prevent proximal migration of pins. Posture, gait, perception of pain and lameness scores were assessed during 15, 30 and 60 day, postoperatively. Caps offered rigid fixation along with intramedullary pin resulting in mild or moderate callus formation. Excellent postoperative functional recovery without any pin migration, seroma formation and valgus limb deformity were observed in group B. Results of present preliminary study suggested that designed capped intramedullary pinning offers stable internal fixation and prevented pin migration, sciatic injury and seroma formation.

Neuroplasticity in the pathogenesis and treatment of chronic pain syndrome: new research and therapeutic perspectives

Recent research and therapeutic outlooks examine the impact of neuroplasticity on the progression and management of chronic pain syndrome. Aims: To review neurobiological basis as well as neuroplastic mechanisms in chronic pain syndrome, exploring bidirectional relationship and innovative therapies and to evaluate efficacy/safety of diverse treatments like TENS, rTMS, pharmacotherapies, and exercise in chronic pain management. Study design: A narrative literature review. Place and Duration of Study: 2019 to 2024. Methodology: A narrative review was conducted using the keywords “Neuroplasticity" AND "Chronic Pain" on PubMed yielded a total of 333 publications. Out of the total publications, 21 were deemed directly relevant, probably providing valuable perspectives on the link between neuroplasticity and chronic pain. Results: Results showed that out of the 11 studies analysed, 7 investigated the bidirectional relationship between chronic pain and neuroplasticity. Additionally, 4 studies reviewed pharmacological methods, 2 studies discussed personalised management and mechanistic profiling, and 7 explored neuromodulation and non-pharmacological interventions. Various neurophysiological correlates of chronic pain were studied, including somatosensory and cortical neurophysiology profiles but Central sensitisation and neuroinflammation were the explored key mechanisms. Activity-dependent plasticity, neuroplasticity in pain modulation, and cortical plasticity are extensively explored, revealing changes in neural activity, synaptic strength, and brain structure. Research explores the connection between chronic pain and neuroplasticity, examining how they impact each other and highlighting the constant interaction between pain perception and neural plasticity. Innovative therapeutic strategies include neuromodulation techniques, pharmacological interventions, personalised pain management, and multimodal approach. Non-invasive brain stimulation, transcutaneous electrical nerve stimulation , and home-based focused tDCS show promise in chronic pain management. Conclusion: In summary, these findings highlighted the multifaceted nature of chronic pain and the on-going efforts to develop effective therapeutic interventions, showcasing a dynamic field of research aiming to improve the lives of those suffering from chronic pain.

Reduced reactivity to fear conditioning and pain tests in persons involved in violent video gaming is influenced by adverse childhood experiences.

Video gaming, including violent video gaming, has become very common and lockdown measures of the COVID-19 pandemic even increased the prevalence rates. In this study, we examined if violent video gaming is associated with more adverse childhood experiences (ACE) and if it impairs pain processing and fear conditioning. We tested three groups of participants (violent video gamers, nonviolent video gamers, and non-gamers) and examined fear conditioning as well as pain perception during functional magnetic resonance imaging (fMRI). Violent video gamers displayed significantly higher pain thresholds as well as pain tolerance for electric stimulation, pressure pain stimulation, and cold pressor pain measurements than nonviolent video gamers and non-gamers. This relationship was moderated by adverse childhood experiences, especially physical neglect. Brain images acquired during the fear conditioning fMRI task showed that violent video gamers display significantly less differential brain activation to stimuli signaling pain versus no pain in the anterior cingulate cortex, the juxtapositional lobule cortex, and the paracingulate gyrus compared to non-gamers. There was also a significant negative correlation between adverse childhood experiences and activation in the precuneus and the intracalcarine cortex for signals of pain versus safety. The results of this study imply that violent video gaming is related to reduced processing of pain and signals of pain in a fear learning task, dependent of adverse childhood experiences. These mechanisms need to be examined in more detail and these data could be helpful in preventing the onset and adverse consequences of violent video gaming.

Men and women undergoing total hip arthroplasty have different clinical presentations before surgery and different outcomes at 1-year follow-up.

The purpose of this study was to investigate the influence of sex on patients undergoing total hip arthroplasty (THA) for hip osteoarthritis (HOA), aiming to assess the clinical and functional outcomes using patient-reported outcome measures (PROMs). A retrospective analysis of patients undergoing THA at Ospedale Galeazzi-Sant'Ambrogio between 2016 and 2022 was conducted. Inclusion criteria encompassed Kellgren-Lawrence grade III or IV HOA, with preoperative and 12-month postoperative PROMs. Enroled patients have been selected from a larger cohort without matching design for confounders. The analyses were performed using R software v4.0.3 (R Core Team) and data distributions were assessed using the Shapiro-Wilk normality test. One hundred ninety patients (72 male and 118 female) who had both preoperative and postoperative PROMs have been analysed from our institutional prosthesis registry (Datareg). Baseline and 12-month post-THA PROMs showed significant improvements overall. VAS score dropped notably from baseline to 3 months postsurgery (7.1 ± 2.1 vs. 0.9 ± 1.7). Functional and mental PROMs, including Harris Hip Score-functional (HHS-F), Harris Hip Score-total (HHS-t), SF-12PSand SF-12MS, exhibited substantial improvements post-THA. Stratifying by sex, males had lower baseline VAS, higher HHS-F, SF-12MSand hip disability and osteoarthritis outcome score-physical function short form (HOOS-PS). At 12 months, males displayed significantly better VAS, HHS-F, SF-12PSand HOOS-PS scores. Complication rates were minimal (1.5%), with stable rates across genders, mostly involving dislocation and periprosthetic fractures. Implant survival at 12 months reached an impressive 99%. THA remains an effective treatment for severe HOA. However, females presented with worse baseline conditions and showed relatively less improvement at 1-year postsurgery compared to males. This difference could be attributed to physiological and psychosocial factors associated with sex, including hormonal changes, muscle mass declineand perception of pain. Longer follow-ups and prospective studies are necessary to validate these findings and facilitate personalised approaches in HOA treatment, emphasising the need for careful consideration of sex-related variables in clinical decision-making for THA patients. Level III.

Can we achieve pain stratification in musculoskeletal conditions? Implications for clinical practice.

In the last few years there has been an increased appreciation that pain perception in rheumatic and musculoskeletal diseases (RMDs) has several mechanisms which include nociceptive, inflammatory, nociplastic and neuropathic components. Studies in specific patient groups have also demonstrated that the pain experienced by people with specific diagnoses can present with distinctive components over time. For example, the pain observed in rheumatoid arthritis has been widely accepted to be caused by the activation of nociceptors, potentiated by the release of inflammatory mediators, including prostaglandins, leukotrienes and cytokine networks in the joint environment. However, people with RA may also experience nociplastic and neuropathic pain components, particularly when treatments with disease modifying anti-rheumatic drugs (DMARDs) have been implemented and are insufficient to control pain symptoms. In other RMDs, the concept of pain sensitisation or nociplastic pain in driving ongoing pain symptoms e.g. osteoarthritis and fibromyalgia, is becoming increasingly recognised. In this review, we explore the hypothesis that pain has distinct modalities based on clinical, pathophysiological, imaging and genetic factors. The concept of pain stratification in RMD is explored and implications for future management are also discussed.

Pain catastrophizing in the elderly: An experimental pain study.

Pain catastrophizing in the aging population has not been studied in great detail. Existing investigations have reported conflicting results on the effects of age on pain catastrophizing in relation to pain responses. This study investigated the relationship between pain catastrophizing, and its individual components (rumination, magnification, and helplessness), and the responses to standardized experimental pain stimuli in old and young, healthy adults. Sixty-six volunteers (32 old: 65-87, 18 females; 34 young: 20-35, 17 females) participated in the study. Pain catastrophizing including the components of rumination, magnification, and helplessness was assessed with the pain catastrophizing scale (PCS). Experimental pain was induced by applying predefined pressure stimulations to the trapezius muscle. Pain intensity and unpleasantness were assessed using numerical rating scales. Pain catastrophizing levels and pain responses were statistically compared between the two age groups. Elderly individuals reported significantly (p = 0.028) lower scores of pain catastrophizing (Med = 5; interquartile range [IQR] = 14) than younger individuals; this difference was driven by the significantly lower components of rumination (Med = 2; IQR = 4; p = 0.017) and helplessness (Med = 2; IQR = 7; p = 0.049). A larger proportion of young (57.8%) rated pain catastrophizing at high levels, with scores above the 75th percentile (Med = 20). Additionally, elderly reported the lowest pain intensity (Med = 5; p = 0.034) and pain unpleasantness (Med = 4.5; p = 0.011) responses to the experimental pressure stimuli. In the elderly group, pain unpleasantness was positively and significantly associated with pain catastrophizing (r s = 0.416, p = 0.021), rumination (r s = 0.42, p = 0.019), and helplessness (r s = 0.434, p = 0.015), respectively. No associations were found in the young group. Elderly reported lower PCSs than young adults. Rumination and helplessness were reduced in the elderly group. The elderly population showed positive correlations between catastrophizing levels and pain unpleasantness to standardized pressure pain stimuli. Results supported the view that elderly possess resilience over specific domains of pain catastrophizing that could counteract pain perception due to physiological decline.

Integration of Prior Expectations and Suppression of Prediction Errors During Expectancy-Induced Pain Modulation: The Influence of Anxiety and Pleasantness.

Pain perception arises from the integration of prior expectations with sensory information. Although recent work has demonstrated that treatment expectancy effects (e.g., placebo hypoalgesia) can be explained by a Bayesian integration framework incorporating the precision level of expectations and sensory inputs, the key factor modulating this integration in stimulus expectancy-induced pain modulation remains unclear. In a stimulus expectancy paradigm combining emotion regulation in healthy male and female adults, we found that participants' voluntary reduction in anticipatory anxiety and pleasantness monotonically reduced the magnitude of pain modulation by negative and positive expectations, respectively, indicating a role of emotion. For both types of expectations, Bayesian model comparisons confirmed that an integration model using the respective emotion of expectations and sensory inputs explained stimulus expectancy effects on pain better than using their respective precision. For negative expectations, the role of anxiety is further supported by our fMRI findings that (1) functional coupling within anxiety-processing brain regions (amygdala and anterior cingulate) reflected the integration of expectations with sensory inputs and (2) anxiety appeared to impair the updating of expectations via suppressed prediction error signals in the anterior cingulate, thus perpetuating negative expectancy effects. Regarding positive expectations, their integration with sensory inputs relied on the functional coupling within brain structures processing positive emotion and inhibiting threat responding (medial orbitofrontal cortex and hippocampus). In summary, different from treatment expectancy, pain modulation by stimulus expectancy emanates from emotion-modulated integration of beliefs with sensory evidence and inadequate belief updating.