Central Sensitization Inventory as a Predictor of Worse Quality of Life Measures and Increased Length of Stay Following Spinal Fusion

Establishing central sensitization inventory cut-off values in Dutch-speaking patients with chronic low back pain by unsupervised machine learning

BACKGROUND

Human Assumed Central Sensitization (HACS) is involved in the development and maintenance of chronic low back pain (CLBP). The Central Sensitization Inventory (CSI) was developed to evaluate the presence of HACS, with a cut-off value of 40/100. However, various factors including pain conditions (e.g., CLBP), contexts, and gender may influence this cut-off value. Unsupervised clustering approaches can address these complexities by considering diverse factors and exploring possible HACS-related subgroups. Therefore, this study aimed to determine the cut-off values for a Dutch-speaking population with CLBP based on unsupervised machine learning.

METHODS

Questionnaire data covering pain, physical, and psychological aspects were collected from patients with CLBP and aged-matched healthy controls (HC). Four clustering approaches were applied to identify HACS-related subgroups based on the questionnaire data and gender. The clustering performance was assessed using internal and external indicators. Subsequently, receiver operating characteristic (ROC) analysis was conducted on the best clustering results to determine the optimal cut-off values.

RESULTS

The study included 63 HCs and 88 patients with CLBP. Hierarchical clustering yielded the best results, identifying three clusters: healthy group, CLBP with low HACS level, and CLBP with high HACS level groups. The cut-off value for the overall groups were 35 (sensitivity 0.76, specificity 0.76).

CONCLUSION

This study found distinct patient subgroups. An overall CSI cut-off value of 35 was suggested. This study may provide new insights into identifying HACS-related patterns and contributes to establishing accurate cut-off values.

Influence of Preoperative Pain, Cognitions, and Quantitative Sensory Testing Measures on the Effects of Perioperative Pain Neuroscience Education for People Receiving Surgery for Lumbar Radiculopathy: Secondary Analysis of a Randomized Controlled Trial

OBJECTIVE: To explore whether preoperative pain intensity, pain cognitions, and quantitative sensory measures influence the established effectiveness of perioperative pain neuroscience education (PPNE) on health-related quality of life at 1 year after surgery for lumbar radiculopathy. DESIGN: Secondary analysis of a triple-blinded randomized controlled trial. METHODS: Participants (n = 90) were Dutch-speaking adults (18-65 years) who were scheduled for surgery for lumbar radiculopathy in 3 Belgian hospitals. They were randomized (1:1) to receive PPNE (n = 41) or perioperative biomedical education (n = 49). Linear mixed models were built for health-related quality of life (ie, SF-6D utility values, Physical and Mental Component of the 36-item Short Form Health Survey) using the following independent variables: therapy, time, and preoperative scores for back and leg pain intensity, pain catastrophizing, kinesiophobia, hypervigilance, and quantitative sensory measures. RESULTS: The impact of PPNE on SF-6D utility values over time was influenced by kinesiophobia (F = 3.30, P = .02) and leg pain intensity (F = 3.48, P = .02). Regardless of the intervention, back pain intensity negatively influenced SF-6D values over time (F = 3.99, P = .009). The Physical Component scores were negatively impacted by back pain intensity (F = 9.08, P = .003) and were influenced over time by leg pain intensity (F = 2.87, P = .04). The Mental Component scores were negatively impacted by back pain intensity (F = 6.64, P = .01) and pain catastrophizing (F = 5.42, P = .02), as well as hypervigilance (F = 3.16, P = .03) and leg pain intensity (F = 3.12, P = .03) over time. CONCLUSION: PPNE may be more effective than perioperative biomedical education in improving postoperative health utility values in patients who reported higher kinesiophobia and leg pain intensity before surgery for lumbar radiculopathy. J Orthop Sports Phys Ther 2024;54(4):1-10. Epub 8 January 2024. doi:10.2519/jospt.2024.12051.

Relationship Between Central Sensitization-Related Symptoms and Pain-Related Disability After Cervical Spine Surgery: A Structural Equation Model

BACKGROUND

It is unknown if central sensitization (CS)-related symptoms have an intermediate role that might explain how disability develops from pain after cervical spinal surgery.

AIMS

The study aim was to investigate the role of CS-related symptoms in the relationship between pain and disability reported after cervical spinal surgery.

DESIGN

Cross-sectional study.

SETTINGS

Tertiary care spinal surgery center.

PARTICIPANTS/SUBJECTS

The participants included individuals with a cervical degenerative condition who had undergone surgery.

METHODS

The following patient-reported outcome measures were evaluated: (1) Numerical Rating Scale; (2) Neck Disability Index; and (3) Short Form of the Central Sensitization Inventory. A hypothesized model containing the CS-related symptoms and the relationships between pain and disability was constructed and tested by structural equation modeling.

RESULTS

Questionnaires were mailed to 280 individuals, and responses were obtained from 145 participants. Of these respondents, 99 (68.3%) were males and 46 (31.7%) were females, with a mean age of 64.4 ± 12.3 years. The latent variable for pain, represented by the neck (coefficient: 0.856, p < .001) and upper limb pain (0.568, p < .001), influenced CS-related symptoms (coefficient: 0.504, p < .001). Pain directly affected disability (coefficient: 0.497, p < .001) and indirectly through CS-related symptoms. Bootstrap analysis confirmed this indirect effect (point estimate: 2.85, 95% confidence interval: 1.04 to 6.30, p = .04).

CONCLUSIONS

The results revealed that neck and upper limb pain affected disabilities both directly and through CS-related symptoms. Future research should focus on the efficacy of biopsychosocial approaches for patients after cervical spine surgery with a high risk of disability due to CS-related symptoms.

Nociceptive, neuropathic, or nociplastic low back pain? The low back pain phenotyping (BACPAP) consortium's international and multidisciplinary consensus recommendations

The potential to classify low back pain as being characterised by dominant nociceptive, neuropathic, or nociplastic mechanisms is a clinically relevant issue. Preliminary evidence suggests that these low back pain phenotypes might respond differently to treatments; however, more research must be done before making specific recommendations. Accordingly, the low back pain phenotyping (BACPAP) consortium was established as a group of 36 clinicians and researchers from 13 countries (five continents) and 29 institutions, to apply a modified Nominal Group Technique methodology to develop international and multidisciplinary consensus recommendations to provide guidance for identifying the dominant pain phenotype in patients with low back pain, and potentially adapt pain management strategies. The BACPAP consortium's recommendations are also intended to provide direction for future clinical research by building on the established clinical criteria for neuropathic and nociplastic pain. The BACPAP consortium's consensus recommendations are a necessary early step in the process to determine if personalised pain medicine based on pain phenotypes is feasible for low back pain management. Therefore, these recommendations are not ready to be implemented in clinical practice until additional evidence is generated that is specific to these low back pain phenotypes.

Towards comprehensive management of symptomatic endometriosis: beyond the dichotomy of medical versus surgical treatment

Except when surgery is the only option because of organ damage, the presence of suspicious lesions, or the desire to conceive, women with endometriosis-associated pain often face a choice between medical and surgical treatment. In theory, the description of the potential benefits and potential harms of the two alternatives should be standardized, unbiased, and based on strong evidence, enabling the patient to make an informed decision. However, doctor's opinion, intellectual competing interests, local availability of specific services and (mis)information obtained from social media, and online support groups can influence the type of advice given and affect patients' choices. This is compounded by the paucity of robust data from randomized controlled trials, and the anxiety of distressed women who are eager to do anything to alleviate their disabling symptoms. Vulnerable patients are more likely to accept the suggestions of their healthcare provider, which can lead to unbalanced and physician-centred decisions, whether in favour of either medical or surgical treatment. In general, treatments should be symptom-orientated rather than lesion-orientated. Medical and surgical modalities appear to be similarly effective in reducing pain symptoms, with medications generally more successful for severe dysmenorrhoea and surgery more successful for severe deep dyspareunia caused by fibrotic lesions infiltrating the posterior compartment. Oestrogen-progestogen combinations and progestogen monotherapies are generally safe and well tolerated, provided there are no major contraindications. About three-quarters of patients with superficial peritoneal and ovarian endometriosis and two-thirds of those with infiltrating fibrotic lesions are ultimately satisfied with their medical treatment although the remainder may experience side effects, which may result in non-compliance. Surgery for superficial and ovarian endometriosis is usually safe. When fibrotic infiltrating lesions are present, morbidity varies greatly depending on the skill of the individual surgeon, the need for advanced procedures, such as bowel resection and ureteral reimplantation, and the availability of expert colorectal surgeons and urologists working together in a multidisciplinary approach. The generalizability of published results is adequate for medical treatment but very limited for surgery. Moreover, on the one hand, hormonal drugs induce disease remission but do not cure endometriosis, and symptom relapse is expected when the drugs are discontinued; on the other hand, the same drugs should be used after lesion excision, which also does not cure endometriosis, to prevent an overall cumulative symptom and lesion recurrence rate of 10% per postoperative year. Therefore, the real choice may not be between medical treatment and surgery, but between medical treatment alone and surgery plus postoperative medical treatment. The experience of pain in women with endometriosis is a complex phenomenon that is not exclusively based on nociception, although the role of peripheral and central sensitization is not fully understood. In addition, trauma, and especially sexual trauma, and pelvic floor disorders can cause or contribute to symptoms in many individuals with chronic pelvic pain, and healthcare providers should never take for granted that diagnosed or suspected endometriosis is always the real, or the sole, origin of the referred complaints. Alternative treatment modalities are available that can help address most of the additional causes contributing to symptoms. Pain management in women with endometriosis may be more than a choice between medical and surgical treatment and may require comprehensive care by a multidisciplinary team including psychologists, sexologists, physiotherapists, dieticians, and pain therapists. An often missing factor in successful treatment is empathy on the part of healthcare providers. Being heard and understood, receiving simple and clear explanations and honest communication about uncertainties, being invited to share medical decisions after receiving detailed and impartial information, and being reassured that a team member will be available should a major problem arise, can greatly increase trust in doctors and transform a lonely and frustrating experience into a guided and supported journey, during which coping with this chronic disease is gradually learned and eventually accepted. Within this broader scenario, patient-centred medicine is the priority, and whether or when to resort to surgery or choose the medical option remains the prerogative of each individual woman.

Characterizing clinical progression in patients with musculoskeletal pain by pain severity and central sensitization-related symptoms

Central sensitization-related symptoms (CSS) are associated with the severity and progression of pain. The relationship between the severity of pain/CSS and clinical progresses remains unclear. This multicenter, collaborative, longitudinal study aimed to characterize the clinical outcomes of patients with musculoskeletal pain by classifying subgroups based on the severity of pain/CSS and examining changes in subgroups over time. We measured the pain intensity, CSS, catastrophic thinking, and body perception disturbance in 435 patients with musculoskeletal pain. Reevaluation of patients after one month included 166 patients for pain intensity outcome and 110 for both pain intensity and CSS outcome analysis. We classified the patients into four groups (mild pain/CSS, severe pain/mild CSS, severe pain/CSS, and mild pain/severe CSS groups) and performed multiple comparison analyses to reveal the differences between the CSS severity groups. Additionally, we performed the adjusted residual chi-square to identify the number of patients with pain improvement, group transition, changing pain, and CSS pattern groups at baseline. The most characteristic result was that the mild and severe CSS groups showed worsening pain. Moreover, many of the group transitions were to the same group, with a few transitioning to a group with mild pain/CSS. Our findings suggest that the severity and improvement of CSS influence pain prognosis.

Effects of sleep quality on pain, cognitive factors, central sensitization, and quality of life in patients with chronic low back pain

BACKGROUND

Sleep quality in patients with chronic low back pain (CLBP) may affect quality of life (QoL), possibly due to worsening pain, central sensitization (CS), and cognitive factors. However, causal relationship among the factors has not been confirmed yet.

OBJECTIVE

The purpose of this study was to test the hypothesis that sleep quality in patients with CLBP is attributable to pain, cognitive factors, and CS, and influences QoL, by structural covariance analysis.

METHODS

This is a cross-sectional study. Participants were recruited from six health care facilities and 101 patients with CLBP were included. Structural covariance analysis assessed the fit of data to the model using goodness of fit index (GFI), adjusted goodness of fit index (AGFI), comparative fit index (CFI), and mean squared approximation error (RMSEA).

RESULTS

The structural covariance analysis showed that the goodness-of-fit indices were high (GFI = 0.993, AGFI = 0.964, CFI = 1.00, RMSEA < 0.01). Sleep quality was not directly influenced by QoL but rather by CS and cognitive factors.

CONCLUSION

This study suggests that sleep quality in patients with CLBP is indirectly mediated through multiple pathways, including cognitive factors and CS, which may influence QoL.

Central sensitization adversely affects quality of recovery following lumbar decompression surgery

BACKGROUND

Central sensitization (CS) is defined as increased responsiveness of nociceptive neurons in the central nervous system to normal or subthreshold afferent input. The CS phenomenon is caused by continuous, intense nociceptor inputs triggering a prolonged but reversible increase in the excitability and synaptic efficacy of neurons in the central nociceptive pathway. Most patients undergoing surgery for lumbar spinal stenosis (LSS) experience symptoms for more than three months; therefore, it is possible that CS is associated with postoperative symptoms of LSS. The aim of this study was to clarify the influence of CS in patients who underwent surgery for LSS.

METHODS

We used the Central Sensitization Inventory (CSI) to evaluate CS preoperatively. Clinical and neurological symptoms were assessed before surgery and three months after surgery using the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOA-BPEQ) and the Oswestry Disability Index (ODI). To evaluate the correlation between the preoperative CSI score and each parameter of the JOA-BPEQ before and three months after surgery, a Pearson correlation coefficient was used. We also evaluated the correlation between preoperative CSI and improvement scores for each parameter of the JOA-BPEQ for surgery. Similarly, the ODI was assessed.

RESULTS

This study included 118 patients. After surgery, the parameters of lumbar function disorder, social life function disorder, and mental health disorder revealed a statistically significant relationship (r = -0.289, -0.0354, and -0.493, respectively). There was no significant correlation between CSI and improvement scores of the JOA-BPEQ. The ODI assessment after surgery revealed a statistically significant relationship (r = 0.344). There was no significant correlation between the CSI and ODI improvement scores.

CONCLUSION

This study showed that the severity of the CSI influenced the postoperative outcomes, and that surgical treatment improved the symptoms of LSS regardless of the occurrence of CS preoperatively.

Central sensitization as a predictive factor for the surgical outcome in patients with lumbar spinal stenosis: a multicenter prospective study

PURPOSE

The impact of central sensitization (CS) on neurological symptoms and surgical outcomes in patients with lumbar spinal stenosis (LSS) remains unknown. This study aimed to investigate the influence of preoperative CS on the surgical outcomes of patients with LSS.

METHODS

A total of 197 consecutive patients with LSS (mean age 69.3) who underwent posterior decompression surgery with or without fusion were included in this study. The participants completed the CS inventory (CSI) scores and the following clinical outcome assessments (COAs) preoperatively and 12 months postoperatively: the Japanese Orthopaedic Association (JOA) score for back pain, JOA back pain evaluation questionnaire, and Oswestry Disability Index (ODI). The association between preoperative CSI scores and preoperative and postoperative COAs was analyzed, and postoperative changes were statistically evaluated.

RESULTS

The preoperative CSI score significantly decreased at 12 months postoperatively and was significantly correlated with all COAs preoperatively and 12 months postoperatively. Higher preoperative CSI showed worse postoperative COAs and inferior postoperative improvement rates in the JOA score, VAS score for neurological symptoms, and ODI. Multiple regression analysis demonstrated that preoperative CSI was significantly associated with postoperative low back pain (LBP), mental health, quality of life (QOL), and neurological symptoms at 12 months postoperatively.

CONCLUSIONS

Preoperative CS evaluated by CSI had a significantly worse impact on surgical outcomes, including neurological symptoms, disability, and QOL, especially related to LBP and psychological factors. CSI can be used clinically as a patient-reported measure for predicting postoperative outcomes in patients with LSS.

Association of central sensitization, visceral fat, and surgical outcomes in lumbar spinal stenosis

BACKGROUND

Controversy remains regarding predictors of surgical outcomes for patients with lumbar spinal stenosis (LSS). Pain sensitization may be an underlying mechanism contributing to LSS surgical outcomes. Further, obesity is associated with dissatisfaction and poorer outcomes after surgery for LSS. Therefore, this study aimed to examine the relationship between central sensitization (CS), visceral fat, and surgical outcomes in LSS.

METHODS

Patients with LSS were categorized based on their central sensitization inventory (CSI) scores into low- (CSI < 40) and high- (CSI ≥ 40) CSI subgroups. The participants completed clinical outcome assessments preoperatively and 12 months postoperatively.

RESULTS

Overall, 60 patients were enrolled in the study (28 men, 32 women; mean age: 62.1 ± 2.8 years). The high-CSI group had significantly higher mean low back pain (LBP), leg pain, and leg numbness visual analogue scale (VAS) scores than the low-CSI group (p < 0.01). The high-CSI group had a significantly higher mean visceral fat area than the low-CSI group (p < 0.01). Postoperatively, LBP VAS score was significantly worse in the high-CSI group. Relative to preoperatively, postoperative leg pain and leg numbness improved significantly in both groups.

CONCLUSIONS

We believe that neuro decompression can be effective for LSS surgical outcomes in patients with CS; nonetheless, it should be approached with caution owing to the potential for worsening LBP. Additionally, visceral fat is an important indicator suggesting the involvement of CS.

Effect of perioperative pain neuroscience education in people undergoing surgery for lumbar radiculopathy: a multicentre randomised controlled trial

BACKGROUND

Perioperative education should be improved to decrease unfavourable outcomes after lumbar surgery. This trial aimed to compare effectiveness in terms of pain, quality of life, pain cognition, surgical experience, healthcare use, work resumption, and cost-effectiveness of perioperative pain neuroscience education (PPNE) vs traditional biomedical education (perioperative biomedical education [PBE]) in people undergoing surgery for lumbar radiculopathy.

METHODS

In this multicentre RCT (ClinicalTrials.gov: NCT02630732), patients undergoing surgery for lumbar radiculopathy in three Belgian hospitals were randomised to receive PPNE or PBE. Both groups received one preoperative and one postoperative one-to-one education session and a booklet (balanced interventions), with an essentially different content (PPNE: biopsychosocial; PBE: biomedical). Pain was the primary outcome (Visual Analogue Scales+quantitative sensory testing). Assessments were at 3 days, 6 weeks, and 6 and 12 months after surgery.

RESULTS

Between March 2016 and April 2020, participants were randomly assigned to PPNE (n=58) or PBE (n=62). At 12 months, PPNE did not lead to significantly better pain outcomes, but it did result in more favourable 36-item Short Form Health Survey physical component (additional increase: 46.94; 95% confidence interval [CI]: 14.16-79.73; medium effect), Tampa Scale of Kinesiophobia (additional decrease: 3.15; 95% CI: 0.25-6.04; small effect), and Pain Catastrophising Scale (additional decrease: 6.18; 95% CI: 1.97-10.39; medium effect) scores. Females of the PPNE group showed higher probability for work resumption (95% vs 60% in the PBE group). PPNE was cost-effective compared with PBE (incremental costs: €-2732; incremental quality-adjusted life years: 0.012).

CONCLUSIONS

Perioperative pain neuroscience education showed superior clinical and cost-effectiveness than perioperative biomedical education in people undergoing surgery for lumbar radiculopathy.

CLINICAL TRIAL REGISTRATION

NCT02630732.

Evaluation of Central Sensitization Inventory in Patients Undergoing Elective Spine Surgery in a Multicenter Study

STUDY DESIGN

This study is a retrospective review.

OBJECTIVE

Central sensitization (CS) is a neurological phenomenon that involves hypersensitivity of the central nervous system. The central sensitization inventory (CSI) was developed as a screening tool to assess CS-related symptoms. The purpose of this study was to evaluate the association of preoperative CSI scores with patient-reported outcome measures (PROMs) including neurological symptoms for patients who underwent spine surgeries in a multicenter study.

METHODS

A consecutive 673 patients who underwent spine surgery at 8 different institutions were included in this study. Preoperative CSI scores were assessed for all subjects. The participants completed the following PROMs: the Oswestry Disability Index (ODI), the Japanese Orthopaedic Association (JOA) back pain evaluation questionnaire (JOABPEQ) for lumbar spinal diseases, and the JOA cervical myelopathy evaluation questionnaire (JOACMEQ) for cervical spinal diseases. The association of CSI scores with PROMs was statistically evaluated.

RESULTS

The average CSI score for the total subjects was 23.6 ± 13.5. The subjects with CS-related symptoms (CSI ≥ 40) were 13.2% (n = 89). The CSI score showed a significant and weak-to-moderate correlation with the PROMs including neurological symptoms that included all the domains of the JOACMEQ for cervical spinal diseases, and JOABPEQ and ODI for lumbar spinal diseases. Among these, psychological factors had the most influence on the correlation with CSI score.

CONCLUSION

Central sensitization evaluated by the CSI is related to neurological symptoms and health-related quality of life in patients undergoing elective spine surgery.

Does Central Sensitization Influence Outcomes of Lumbar Discectomy Surgery in Patients With Lumbar Disc Herniation? A Multicenter Prospective Study

STUDY DESIGN

Multicenter prospective study.

OBJECTIVE

Patients with central sensitization (CS) are reported to be at high risk of poor outcomes after spinal surgery. However, the influence of CS on surgical outcomes for lumbar disc herniation (LDH) remains unknown. This study aimed to examine the association between preoperative CS and surgical outcomes in LDH patients.

METHODS

A total of 100 consecutive patients with LDH (mean age 51.2) who underwent lumbar surgery were included in this study. The extent of CS was evaluated using the central sensitization inventory (CSI), a screening tool for CS-related symptoms. The patients completed the following CSI and clinical outcome assessments (COAs) preoperatively and 12 months postoperatively: the Japanese Orthopaedic Association (JOA) score for back pain, JOA back pain evaluation questionnaire (JOABPEQ), and Oswestry Disability Index (ODI). The association between preoperative CSI scores, and preoperative and postoperative COAs was analyzed, and the postoperative changes were statistically evaluated.

RESULTS

The preoperative CSI score significantly decreased 12 months postoperatively. Preoperative CSI scores showed a significant correlation with most COAs; however, a significant correlation was only identified in the social function and mental health domains of JOABPEC postoperatively. Higher preoperative CSI showed worse preoperative COAs; however, all COAs significantly improved regardless of CSI severity. There were no significant differences in any COAs among the CSI severity groups 12 months postoperatively.

CONCLUSIONS

The results of this study showed that lumbar surgeries significantly improved the COAs regardless of preoperative severity of CS in patients with LDH.

Predictors of persistent post-surgical pain intensity and interference at 1 year after breast cancer surgery: assessing central sensitization, central sensitivity symptoms, and psychological factors

BACKGROUND

Persistent post-surgical pain (PPSP) is associated with upper limb dysfunction and decreased quality of life and causes long-term suffering for breast cancer survivors after surgery. However, the predictors of PPSP remain unclear. The purpose of this study was to examine predictors of PPSP intensity and interference at 1 year postoperatively, focusing on treatment-related factors, pre- and postoperative central sensitization (CS), CS-related symptoms (e.g., muscle stiffness, fatigue, sleep disturbances), and psychological factors.

METHODS

Eighty-eight women with planned unilateral breast cancer surgery were included in this longitudinal study. CS, CS-related symptoms, and psychological factors were assessed preoperatively, 1 month postoperatively, and 1 year postoperatively. Analysis of covariance was used to compare the groups with and without PPSP, accounting for treatment-related factors. Multiple regression analysis was performed to identify predictors of PPSP intensity and interference at 1 year postoperatively.

RESULTS

Even after adjusting for covariates, preoperative and 1-month postoperative Central Sensitization Inventory scores in the PPSP group were significantly higher than scores in the group without PPSP. Multiple regression analysis showed that axillary lymph node dissection (ALND) and 1-month postoperative CS-related symptoms were independent predictors of PPSP intensity and interference at 1 year postoperatively (p < 0.01).

CONCLUSION

We found that ALND and 1-month postoperative CS-related symptoms were predictors of PPSP intensity and interference at 1 year postoperatively.

Association of Central Sensitization Inventory Scores With Pain Outcomes After Endometriosis Surgery

IMPORTANCE

A subset of people who undergo surgery for endometriosis have persistent pain, suggesting that other factors besides the endometriosis, such as central sensitization, may play a role in this pain. The Central Sensitization Inventory, a validated self-reported questionnaire of central sensitization symptoms, may identify individuals with endometriosis who have more pain after surgery due to pain sensitization.

OBJECTIVE

To examine whether greater baseline Central Sensitization Inventory scores are associated with postsurgical pain outcomes.

DESIGN, SETTING, AND PARTICIPANTS

This prospective, longitudinal cohort study performed at a tertiary center for endometriosis and pelvic pain in British Columbia, Canada, included all patients aged 18 to 50 years with diagnosed or suspected endometriosis and a baseline visit between January 1, 2018, and December 31, 2019, who underwent surgery after the baseline visit. Individuals who were menopausal, had a prior hysterectomy, or were missing data for outcomes or measures were excluded. Data analysis was performed from July 2021 to June 2022.

MAIN OUTCOMES AND MEASURES

The primary outcome was chronic pelvic pain at follow-up measured on a scale of 0 to 10, with 0 to 3 indicating no pain or mild pain, 4 to 6 indicating moderate pain, and 7 to 10 indicating severe pain. Secondary outcomes were deep dyspareunia, dysmenorrhea, dyschezia, and back pain at follow-up. The main variable of interest was baseline Central Sensitization Inventory score (measured from 0 to 100, consisting of 25 self-reported questions rated from 0 to 4 [never, rarely, sometimes, often, and always, respectively]).

RESULTS

A total of 239 patients (mean [SD] age, 34 [7] years; 189 [79.1%] White [11 (5.8%) identified as White mixed with another ethnicity], 1 [0.4%] Black or African American, 29 [12.1%] Asian, 2 [0.8%] Native Hawaiian or Pacific Islander, 16 [6.7%] other, and 2 [0.8%] mixed race or ethnicity) with follow-up data at more than 4 months after surgery were included in this study (71.0% follow-up rate). The mean (SD) baseline Central Sensitization Inventory score was 43.8 (18.2), and the mean (SD) follow-up was 16.1 (6.1) months. Higher baseline Central Sensitization Inventory scores were significantly associated with higher chronic pelvic pain (odds ratio [OR], 1.02; 95% CI, 1.00-1.03; P = .02), deep dyspareunia (OR, 1.03; 95% CI, 1.01-1.04; P = .004), dyschezia (OR, 1.03; 95% CI, 1.01-1.04; P < .001), and back pain (OR, 1.02; 95% CI, 1.00-1.03; P = .02) at follow-up, when controlling for baseline pain scores. The Central Sensitization Inventory scores themselves decreased slightly from baseline to follow-up (mean [SD] score, 43.8 [18.2] vs 41.7 [18.9]; P = .05); however, individuals with high baseline Central Sensitization Inventory scores still had high scores at follow-up.

CONCLUSIONS AND RELEVANCE

In this cohort study of 239 patients with endometriosis, higher Central Sensitization Inventory scores at baseline were associated with worse pain outcomes after endometriosis surgery, when controlling for baseline pain scores. The Central Sensitization Inventory could be used to counsel patients with endometriosis on their expected outcomes after surgery.

Axial Spondyloarthritis: Reshape the Future-From the "2022 GISEA International Symposium"

The term "axial spondyloarthritis" (axSpA) refers to a group of chronic rheumatic diseases that predominantly involve the axial skeleton and consist of ankylosing spondylitis, reactive arthritis, arthritis/spondylitis associated with psoriasis (PsA) and arthritis/spondylitis associated with inflammatory bowel diseases (IBD). Moreover, pain is an important and common symptom of axSpA. It may progress to chronic pain, a more complicated bio-psychosocial phenomena, leading to a significant worsening of quality of life. The development of the axSpA inflammatory process is grounded in the complex interaction between genetic (such as HLA B27), epigenetic, and environmental factors associated with a dysregulated immune response. Considering the pivotal contribution of IL-23 and IL-17 in axSpA inflammation, the inhibition of these cytokines has been evaluated as a potential therapeutic strategy. With this context, here we discuss the main pathogenetic mechanisms, therapeutic approaches and the role of pain in axSpA from the 2022 International GISEA/OEG Symposium.

The relationship between the Keele STarT back screening tool, the short form of central sensitivity inventory and health-related quality of life in patients with low back pain

INTRODUCTION

It has been reported that the scores of the Keele STarT Back Screening Tool (SBST) and the short form of Central Sensitization Inventory (CSI-9) are associated with Health-Related Quality of Life (HRQoL) in patients with low back pain (LBP). However, it is unclear which screening tool is more associated with HRQoL in patients with LBP.

OBJECTIVE

To identify which SBST and CSI-9 are more related to HRQoL and investigate the association between SBST and CSI-9 scores.

STUDY DESIGN

Cross-sectional study.

METHOD

A multiple regression analysis was conducted to examine the factors associated with the HRQoL using age, pain intensity, disability, SBST score, and CSI-9 score as independent variables. Spearman's rank correlation coefficient was also conducted to determine the association between SBST and CSI-9 score.

RESULTS

Multiple regression analysis revealed that the Oswestry Disability Index (ODI) score (p < 0.01, β = -0.62, VIF = 1.70) and SBST score (p < 0.01, β = -0.32, VIF = 1.86) were significant associated variables. A significant association was found between SBST and CSI-9 scores (p < 0.01, ρ = 0.47).

CONCLUSION

The results showed that in patients with LBP the association of HRQoL with SBST was more substantial than with CSI-9.

Resistance training protects against muscle pain through activation of androgen receptors in male and female mice

ABSTRACT

Resistance training-based exercise is commonly prescribed in the clinic for the treatment of chronic pain. Mechanisms of aerobic exercise for analgesia are frequently studied, while little is known regarding resistance training mechanisms. We developed a resistance training model in mice and hypothesized resistance training would protect against development of muscle pain, mediated through the activation of androgen receptors. Activity-induced muscle hyperalgesia was produced by 2 injections of pH 5.0 stimuli with fatiguing muscle contractions. Resistance training was performed by having mice climb a ladder with attached weights, 3 times per week. Resistance training acutely increased blood lactate and prolonged training increased strength measured via forepaw grip strength and 1 repetition maximum, validating the exercise program as a resistance training model. Eight weeks of resistance training prior to induction of the pain model blocked the development of muscle hyperalgesia in both sexes. Resistance training initiated after induction of the pain model reversed muscle hyperalgesia in male mice only. A single resistance training bout acutely increased testosterone in male but not female mice. Administration of the androgen receptor antagonist flutamide (200 mg pellets) throughout the 8-week training program blocked the exercise-induced protection against muscle pain in both sexes. However, single administration of flutamide (1, 3, 10 mg/kg) in resistance-trained animals had no effect on existing exercise-induced protection against muscle pain. Therefore, resistance training acutely increases lactate and testosterone and strength overtime. Eight weeks of resistance training prevents the development of hyperalgesia through the activation of androgen receptors in an animal model of muscle pain.

Early response to JAK inhibitors on central sensitization and pain catastrophizing in patients with active rheumatoid arthritis

Objectives

To evaluate the effect of 4 weeks of treatment with Janus kinase inhibitors (JAKis) on central sensitization (CS) and pain catastrophizing, and to determine the pain-related variables predictive of disease activity improvement, in patients with active rheumatoid arthritis (RA).

Methods

Consecutive RA patients with active disease starting a JAKi have been enrolled in this prospective observational study. Patients have been assessed at baseline and after 4 weeks of treatment. The evaluation was comprehensive of disease activity [Simplified Disease Activity Index (SDAI) and ultrasonographic (US) score] and of questionnaires aimed at investigating primarily CS [Central Sensitization Inventory (CSI)] and pain catastrophizing [Pain Catastrophizing Scale (PCS)]. Differences (Δ values) between the final and baseline were studied with the t test, Δ values of the variables were correlated with each other using Pearson’s test, and predictor variables for improvement in SDAI were also investigated using multivariate regression analysis.

Results

A total of 115 patients were evaluated. Overall, all variables demonstrated significant improvement between baseline and final except the US score. In particular, CSI decreased from 36.73 to 32.57 (p < 0.0001), PCS decreased from 32.46 to 28.72 (p = 0.0001). ΔSDAI showed a significant correlation with both ΔPCS and ΔCSI (r = 0.466 and 0.386, respectively, p < 0.0001). ΔPCS was the only variable predictive of an improvement in SDAI (coefficient = 0.500, p = 0.0224).

Conclusion

JAKis would appear to have a positive effect on pain-related variables, particularly CS and pain catastrophizing, for the genesis of which extra-synovial mechanisms are responsible.

Signs Indicative of Central Sensitization Are Present but Not Associated with the Central Sensitization Inventory in Patients with Focal Nerve Injury

Objective: Carpal tunnel syndrome (CTS) is the most common focal nerve injury. People with CTS may show alterations in central processing of nociceptive information. It remains unclear whether the central sensitization inventory (CSI) is capable of detecting such altered central pain processing. Methods: Thirty healthy volunteers were matched with 30 people with unilateral CTS from the orthopaedic waitlist. Changes to central pain processing were established through psychophysical sensory testing (bilateral pressure pain thresholds (PPT), conditioned pain modulation, temporal summation) and pain distribution on body charts. Patients also completed pain severity and function questionnaires, psychological questionnaires and the CSI. Results: Compared to healthy volunteers, patients with CTS have lower PPTs over the carpal tunnel bilaterally (t = −4.06, p < 0.0001 ipsilateral and t = −4.58, p < 0.0001 contralateral) and reduced conditioned pain modulation efficacy (t = −7.31, p <0.0001) but no differences in temporal summation (t = 0.52, p = 0.60). The CSI was not associated with psychophysical measures or pain distributions indicative of altered central pain processing. However, there was a correlation of the CSI with the Beck Depression Inventory (r = 0.426; p = 0.019). Conclusion: Patients with CTS show signs of altered central pain mechanisms. The CSI seems unsuitable to detect changes in central pain processing but is rather associated with psychological factors in people with focal nerve injuries.

Characteristics of clusters with contrasting relationships between central sensitization-related symptoms and pain

The central sensitization inventory (CSI) evaluates the central sensitization (CS)-related symptoms associated with increased pain sensitivity. However, the CSI includes items that are not directly related to pain. In this study, 146 patients with pain were classified into subgroups by k-means cluster analysis based on the short form of the central sensitization inventory (CSI9) and pain scores. In addition, inter-group and multiple comparisons were performed to examine the characteristics of each group. As a result of this study, there were three subgroups (clusters 1, 2, and 3) in which the CSI9 and pain intensity were both low, moderate, and high, and one subgroup (cluster 4) in which only CSI9 was high and pain intensity was low. Two subgroups with high CSI9 scores but contrasting pain intensities (clusters 3 and 4) were extracted; the pattern of CS-related symptoms in these two groups was very similar, with no differences in most of the non-pain factors. It is necessary to consider these points when interpreting the clinical condition of a patient with pain when using the assessment of CS-related symptoms.

Central sensitization inventory in endometriosis

ABSTRACT

A key clinical problem is identifying the patient with endometriosis whose pain is complicated by central nervous system sensitization, where conventional gynecologic treatment (eg, hormonal therapy or surgery) may not completely alleviate the pain. The Central Sensitization Inventory (CSI) is a questionnaire previously validated in the chronic pain population. The objective of this study was an exploratory proof-of-concept to identify a CSI cutoff in the endometriosis population to discriminate between individuals with significant central contributors (identified by central sensitivity syndromes [CSS]) to their pain compared to those without. We analyzed a prospective data registry at a tertiary referral center for endometriosis, and included subjects aged 18 to 50 years with endometriosis who were newly or re-referred to the center in 2018. The study sample consisted of 335 subjects with a mean age of 36.0 ± 7.0 years. An increasing number of CSS was significantly correlated with dysmenorrhea, deep dyspareunia, dyschezia, and chronic pelvic pain scores (P < 0.001), and with the CSI score (0-100) (r = 0.731, P < 0.001). Receiver operating characteristic analysis indicated that a CSI cutoff of 40 had a sensitivity of 78% (95% CI: 72.7%-84.6%) and a specificity of 80% (95% CI: 70.3%-84.5%) for identifying a patient with endometriosis with ≥3 CSS. In the group with CSI ≥ 40, 18% retrospectively self-reported pain nonresponsive to hormonal therapy and 40% self-reported daily pain, compared with 6% and 20% in the CSI < 40 group (P = 0.003 and 0.002, respectively). In conclusion, a CSI ≥ 40 may be a practical tool to help identify patients with endometriosis with pain contributors related to central nervous system sensitization.

Scientific Knowledge Graph and Trend Analysis of Central Sensitization: A Bibliometric Analysis

Background

Central sensitization refers to a state of hypersensitivity in the central nervous system and is associated with the development and maintenance of chronic pain. Central sensitization plays an essential role in various diseases. Nevertheless, there has been no bibliometric analysis before in this field. The purpose of this study was to provide critical themes and trends in the area of central sensitization, to build a network of knowledge, and to facilitate the future development of relevant basic and clinical research.

Methods

Publications on central sensitization were extracted from the Science Citation Index-Expanded. We used R software to systematically analyze the countries, institutions, authors, journals, references, and keywords of the publications. Besides, conceptual structure, intellectual structure, and social structure were constructed.

Results

A total of 4466 publications were included. Research in the field of central sensitization generally showed a steady upward trend. The three structural networks showed that the United States is the leading country in this field. Arendt-Nielsen L and Woolf CJ were the most productive and influential authors, respectively. “Pain” was the journal with the most studies. Most journals that published and cited articles about central sensitization were academically influential. Cluster analysis revealed that research in central sensitization contains three main conceptual clusters, and the themes of research evolve frequently. Current research focuses on the pathogenesis of central sensitization in neuropathic pain, the role of central sensitization in different diseases, and related clinical double-blind trials.

Conclusion

Central sensitization received widespread attention. The United States led the way in academic activity. In this field, the current situation of cooperation and communication between different countries and institutions is positive. The present research hotspots were the pathogenesis of central sensitization in neuropathic pain, the role of central sensitization in different diseases, and related clinical double-blind trials.

Central sensitization has major impact on quality of life in patients with axial spondyloarthritis

INTRODUCTION

Persistent pain has large potential impact on quality of life (QoL). During the course of the disease, many patients with axial spondyloarthritis (axSpA) report persistent pain. Central sensitization (CS) may explain part of this chronic pain. However, the role of CS in relation to QoL has been sparsely studied in axSpA. Therefore, our aim was to explore the relationship between CS and QoL in patients with axSpA.

METHODS

Consecutive outpatients from the Groningen Leeuwarden axSpA (GLAS) cohort completed the Central Sensitization Inventory (CSI; range 0-100) and the AS Quality of Life (ASQoL; range 0-18). Multivariable linear regression analysis was used to explore the relationship between CSI and ASQoL scores correcting for potential confounders.

RESULTS

Of the 178 included axSpA patients, mean CSI score was 38.0 ± 14.1 and 45% scored ≥40, which indicates a high probability of CS. Mean ASQoL score was 6.0 ± 5.3 and mean ASDAS_CRP 2.1 ± 1.0. A CSI score ≥40 was significantly associated with higher ASQoL score (mean 9.7 vs. 3.3), higher ASDAS_CRP (mean 2.6 vs. 1.7), female gender (60% vs. 29%) and more often entheseal involvement (61% vs. 26%). In univariable analysis, CSI score explained a large proportion of the variation in ASQoL (B = 0.06, 95%CI: 0.05-0.07; R²=0.46). This association remained significant after correction for ASDAS_CRP, gender, entheseal involvement, comorbidities, symptom duration, smoking status, BMI class and educational level (B = 0.04, 95%CI: 0.03-0.05).

CONCLUSION

CS is strongly related to patient-reported QoL in patients with axSpA independently from other patient- and disease-related aspects.

A large-scale population-based epidemiological study on the prevalence of central sensitization syndromes in Japan

A cross-sectional study of 21,665 Japanese residents was performed to investigate the prevalence of central sensitization syndromes (CSS). CSS were assessed using the Central Sensitization Inventory (CSI-A). CSS were defined as a CSI-A score of 40 or higher. Age, sex, district, 10 CSS-related diseases (CSI-B), lifestyle, and mental factors were rated in a self-reported survey. The prevalence of CSS and its relationship with potential factors were examined by sex using descriptive and logistic regression models. The prevalence of CSS was 4.2% in all participants and was significantly higher in women (4.9%) than in men (2.7%). Adjusted odds ratios correlated with CSS for an age of 80–97 years versus 60–79 years (2.07 and 2.89), one or more CSI-B diseases (3.58 and 3.51), few sleeping hours (2.18 and 1.98), high perceived stress (5.00 and 4.91), low (2.94 and 2.71) and high (0.45 and 0.66) resilience versus moderate resilience, and exercise habits (0.68 and 0.55) in men and women (all P < 0.05). The relationship between CSS and age 20 and 59 years, ex-smokers, coffee intake, and alcohol intake differed by sex. The prevalence of CSS was estimated to be low in the healthy population. CSS correlated with CSS-related diseases and some positive and negative factors.

Do patients with low back pain and central sensitization have differences in physical fitness?

INTRODUCTION

Low back pain is one of the main musculoskeletal complaints, and may be associated with central sensitization (CS). The physical capacity of patients with low back pain and CS is not very clear.

METHODS

A cross-sectional study, with 92 patients divided into two groups according to their risk of CS. The patient's physical capacity ability was assessed using 6-min walking test (6MWT); timed up and go test (TUG); sit-to-stand test (STS); and trunk flexor, extensor and side-bridge endurance tests. In addition, participants completed questionnaires regarding disability, kinesiophobia, catastrophization and quality of life.

RESULTS

The group with a higher risk of CS had worst performance in the 6MWT (U = 1248; p < 0.001), STS (t(83) = 3.63; p < 0.001) and TUG (t(83) = -4.46; p < 0.001). Similarly, endurance in the right (U = 1453,5; p = 0,002) and left (U = 1467; p = 0,003) side-bridge tests, and the trunk extensor test (U = 1546; p = 0,003) was worse. Disability (U = 1272; p < 0.001), physical capacity kinesiophobia (t(83) = -2.21; p = 0.03) work kinesiophobia (U = 1452; p < 0.001), and pain catastrophization (t(77.57) = -5.03; p < 0.001), were also higher in the group with a higher risk of CS. Quality of life indicators were worse in the higher risk group for all domains of the EQ-5D-3L: Mobility (X²(1) = 12.92; p < 0.001), self-care (X²(1) = 16,3; p = 0,012), usual activities (X²(2) = 14.14; p = 0.001), pain (X²(2) = 27.79; p < 0.001), anxiety and depression (X²(2) = 15.05; p = 0.001).

CONCLUSION

Patients with low back pain and higher risks of CS appear to show lower performance in physical capacity tests, higher rates of disability, kinesiophobia, pain catastrophization, and lower quality of life compared to those with lower risks of CS.

Can Central Sensitization after injury persist as an autonomous pain generator? - A comprehensive search for evidence

OBJECTIVE

To conduct a comprehensive search for evidence whether Central Sensitization following an injury can act as a persistent autonomous pain generator after the inducing injury has healed.

METHODS

We searched Medline on PubMed and the Cochrane Library, screening 3,572 abstracts, from which 937 full text articles were obtained, with 186 of these discarded as irrelevant to the question being posed. The remaining 751 articles were studied for evidence.

RESULTS

Fourteen publications were judged to provide weak evidence for the hypothesis of central sensitization as a persisting autonomous pain generator, but none addressed the question directly. No strong evidence for the affirmative answer was found.Sixty-two publications were judged to provide weak evidence for a negative answer, and nine judged to provide strong evidence.Unexpectedly, serious weaknesses were discovered in the literature underpinning the validity of the clinical diagnosis of Central Sensitization in man:(i)  Inappropriate extrapolation, in many publications, of laboratory animal data to humans.(ii) Failure to demonstrate the absence of peripheral pain generators which might be perpetuating Central Sensitization.(iii) Many factors now shown to confound what is being measured by quantitative sensory testing, conditioned pain modulation, and Central Sensitization Inventory.

CONCLUSIONS

We found no evidence proving that central sensitization can persist as an autonomous pain generator after the initiating injury has healed.Our review has also shown that the evidential basis for the diagnosis of CS in individual patients is seriously in question.

Adaptive body awareness predicts fewer central sensitization-related symptoms and explains relationship between central sensitization-related symptoms and pain intensity: A cross-sectional study among individuals with chronic pain

BACKGROUND

Central sensitization (CS), defined as the amplification of neural signaling within the CNS that elicits pain hypersensitivity, is thought be a characteristic of several chronic pain conditions. Maladaptive body awareness is thought to contribute and maintain CS. Less is known about the relationship between CS and adaptive body awareness.

PURPOSE

This cross-sectional study investigated relationships among self-reported adaptive body awareness (Multidimensional Interoceptive Awareness Scale-2; MAIA-2), CS-related symptoms (Central Sensitization Inventory; CSI), and pain intensity and further delineate potential direct and indirect links among these constructs.

METHODS

Online surveys were administered to 280 individuals with chronic pain reporting elevated CSI scores. Strategic sampling targeted respondents to reflect the 2010 census. Pearson's correlations characterized overall relationship between variables. Multiple regression analyses investigated potential direct links. A path analysis assessed mediational effects of CS-related symptoms on the relationship between adaptive body awareness and pain intensity.

RESULTS

CSI demonstrated strong, inverse correlations with some MAIA-2 subscales, but positive correlations with others. Higher CSI scores predicted greater pain intensity (b = 0.049, p ≤ 0.001). Two MAIA-2 subscales, Not-Distracting (b = -0.56, p ≤ 0.001) and Not-Worrying (b = -1.17, p ≤ 0.001) were unique predictors of lower CSI. Not-Distracting (b = -0.05, p = 0.003) and Not-Worrying (b = -0.06, p = 0.007) uniquely predicted lower pain intensity. CSI completely mediated the relationship between adaptive body awareness and pain intensity [point estimate = -0.04; 95% bootstrap confident intervals (CI) = -0.05 to -0.02].

CONCLUSIONS

Findings also support future research to explore causal relationships of variables. Findings suggest that frequency of attention to bodily sensations is distinct from cognitive-affective appraisal of bodily sensation, and the two distinct higher order processes may have divergent influences on perceived pain and CS-related symptoms. Results also support future research to explore causal relationships of variables.

Health-related quality of life deviations from population norms in patients with lumbar radiculopathy: associations with pain, pain cognitions, and endogenous nociceptive modulation

PURPOSE

The primary goal of this study was to compare the health-related quality of life (HRQoL) of people with lumbar radiculopathy to age- and sex-adjusted population norms. Additionally, it aimed to explore the associations between the HRQoL difference scores and measures related to pain cognitions, pain intensity, and endogenous nociceptive modulation.

METHODS

Using answers from the Short Form 36-item Health Survey and UK population norms, SF-6D difference scores were calculated. A one-sample t test was used to assess the SF-6D difference scores. Univariate and multivariate regression analyses were used to assess the associations between SF-6D difference scores and pain intensity [Visual Analogue Scale (VAS) for back and leg pain], pain cognitions [Pain Catastrophizing Scale (PCS), Tampa Scale for Kinesiophobia (TSK), Pain Vigilance and Awareness Questionnaire (PVAQ)], and correlates for endogenous nociceptive modulation using quantitative sensory testing.

RESULTS

One hundred and twenty people with lumbar radiculopathy scheduled for surgery were included in this study. The mean SF-6D difference score of - 0.26 [SD = 0.09] was found to be significantly less than 0 [95%CI: - 0.27 to - 0.24]. Univariate analyses showed a significant influence from PCS, TSK, and PVAQ on the SF-6D difference scores. The final multivariate regression model included PCS and PVAQ, with only PCS maintaining a statistically significant regression coefficient [b = - 0.002; 95% CI: - 0.004 to - 0.001].

CONCLUSION

People diagnosed with lumbar radiculopathy report significantly lower HRQoL scores when compared with age- and sex-adjusted UK norm values. Even though all examined pain cognitions were found to have a significant association, pain catastrophizing showed the most significant relation to the SF-6D difference scores.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov Identifier No. NCT02630732. Date of registration: November 25, 2015.

Nociplastic Pain Criteria or Recognition of Central Sensitization? Pain Phenotyping in the Past, Present and Future

Recently, the International Association for the Study of Pain (IASP) released clinical criteria and a grading system for nociplastic pain affecting the musculoskeletal system. These criteria replaced the 2014 clinical criteria for predominant central sensitization (CS) pain and accounted for clinicians' need to identify (early) and correctly classify patients having chronic pain according to the pain phenotype. Still, clinicians and researchers can become confused by the multitude of terms and the variety of clinical criteria available. Therefore, this paper aims at (1) providing an overview of what preceded the IASP criteria for nociplastic pain ('the past'); (2) explaining the new IASP criteria for nociplastic pain in comparison with the 2014 clinical criteria for predominant CS pain ('the present'); and (3) highlighting key areas for future implementation and research work in this area ('the future'). It is explained that the 2021 IASP clinical criteria for nociplastic pain are in line with the 2014 clinical criteria for predominant CS pain but are more robust, comprehensive, better developed and hold more potential. Therefore, the 2021 IASP clinical criteria for nociplastic pain are important steps towards precision pain medicine, yet studies examining the clinimetric and psychometric properties of the criteria are urgently needed.

Criterion validity and discriminatory ability of the central sensitization inventory short form in individuals with inflammatory bowel diseases

OBJECTIVES

Increased symptoms related to central sensitization have previously been reported in inflammatory bowel disease (IBD) patients, identified by the original central sensitization inventory (CSI-25). However, the recently developed CSI short form (CSI-9) may be more clinically useful. The aim of the present study was to evaluate the performance of CSI-9 compared to the original CSI-25 in individuals with IBD. Study objectives were to investigate the criterion validity of the CSI-9 to the CSI-25, assess individual association of the CSI measures with clinical features of IBD and pain presentations, and to establish disease-specific CSI-9 and CSI-25 cut-off scores for discriminating the presence of self-reported pain in individuals with IBD.

METHODS

Cross-sectional online survey was performed on adults with IBD exploring self-reported demographics, comorbidity, and clinical IBD and pain features. Criterion validity of the CSI-9 was investigated using intraclass correlation coefficient (ICC)_3,1. Area under the receiver operating characteristic curve (AUC-ROC) analysis was conducted to investigate the discriminative ability of both versions of CSI.

RESULTS

Of the 320 participants, 260 reported the presence of abdominal and/or musculoskeletal pain. CSI-9 and CSI-25 demonstrated substantial agreement (ICC_3,1=0.64, 95% CI [0.58, 0.69]). AUC (95% CI) indicated that CSI-9 (0.788 (0.725, 0.851), p<0.001) and CSI-25 (0.808 (0.750, 0.867), p<0.001) were able to adequately discriminate the presence of pain using cut-offs scores of ≥17 (CSI-9) and ≥40 (CSI-25). Abdominal pain severity was the only feature to differ in significant association to CSI-25 (p=0.002) compared to CSI-9 (p=0.236). All other features demonstrated significant associations to both CSI versions, except age (p=0.291 and 0.643) and IBD subtype (p=0.115 and 0.675).

CONCLUSIONS

This is the first study to explore and validate the use of CSI-9 in IBD patients. Results demonstrated concurrent validity of the CSI-9 to CSI-25, with similar significant association to multiple patient features, and a suggested cut-off value of 17 on CSI-9 to screen for individuals with pain experiences. Study findings suggest that CSI-9 is suitable to use as a brief tool in IBD patients.

Establishing Central Sensitization-Related Symptom Severity Subgroups: A Multicountry Study Using the Central Sensitization Inventory

OBJECTIVES

The goal of this study was to identify central sensitization-related symptom severity subgroups in a large multicountry sample composed of patients with chronic pain and pain-free individuals using the Central Sensitization Inventory (CSI).

METHODS

A large, pooled international (N = 8 countries) sample of chronic pain patients plus healthy subjects (total N = 2,620) was randomly divided into two subsamples for cross-validation purposes. First, a hierarchical cluster analysis (HCA) was performed using CSI item-level data as clustering variables (test sample; N = 1,312). Second, a latent profile analysis (LPA) was conducted to confirm the optimal number of CSI clusters (validation sample; N = 1,308). Finally, to promote implementation in real-world clinical practice, we built a free online Central Sensitization Inventory Symptom Severity Calculator.

RESULTS

In both HCA (N = 1,219 valid cases) and LPA (N = 1,245 valid cases) analyses, a three-cluster and three-profile solution, respectively, emerged as the most statistically optimal and clinically meaningful. Clusters were labeled as follows: (i) Low Level of CS-Related Symptom Severity, (ii) Medium Level of CS-Related Symptom Severity, and (iii) High Level of CS-Related Symptom Severity.

CONCLUSIONS

Our results indicated that a three-cluster solution clearly captured the heterogeneity of the CSI data. The calculator might provide an efficient way of classifying subjects into the cluster groups. Future studies should analyze the extent to which the CSI cluster classification correlates with other patient-reported and objective signs and symptoms of CS in patients with chronic pain, their associations with clinical outcomes, health-related costs, biomarkers, (etc.), and responsiveness to treatment.

Central Sensitization in Chronic Musculoskeletal Pain Disorders in Different Populations: A Cross-Sectional Study

OBJECTIVE

Chronic musculoskeletal pain disorders (CMPDs) are among the leading causes of disabilities across populations, resulting in high social and financial burden. This persistent pain condition may include the central sensitization (CS) phenomenon, which implies a wide range of symptoms and that may be taken into account in CMPD treatment. CS symptoms can be measured by the Central Sensitization Inventory (CSI). The aims of the study were to describe CS symptoms in patients suffering from several CMPDs and to analyze differences due to gender, age, and body mass index (BMI).

DESIGN

This cross-sectional study recruited a total of 395 Spanish participants suffering from several CMPDs.

SETTING

CS symptoms were measured with the Spanish Version of the CSI. The total score (0-100) and a cutoff score of 40 were recorded.

SUBJECTS

A total of 395 participants were included.

RESULTS

The mean CSI total score for the whole sample was 24.6 ± 12.0 points. CSI total score had subclinical values in the whole sample, whereas participants with scores >40 were found across different CMPDs, such as low back pain (37.8%) and neck pain (32.4%); 14.6% of females and 1.7% of males presented CSI scores >40. Patients showed significant differences in CSI cutoff point by gender (P = 0.010) and CSI total score by age (P = 0.014).

CONCLUSIONS

Given the high prevalence of clinically relevant CSI scores (>40) in people with a CMPD, especially low back pain and neck pain, we recommend that clinicians supplement their assessment with the CSI for improved decision-making during treatment.

Association between central sensitivity syndrome and psychological factors in people with presurgical low back pain: A cross-sectional study

BACKGROUND

Low back pain (LBP) is a major problem; it causes significant burden, incurs considerable economic and human costs, and adversely affects the quality of life (QoL). Central sensitivity syndrome (CSS) is known as a group of overlapping conditions that share a common pathophysiological mechanism of central sensitization. Previous studies have shown that CSS is present in several disorders. However, it has been studied for people with presurgical LBP. The purpose of the study was to investigate the proportion of patients with CSS for presurgical LBP and to analyse the association of CSS with clinical symptoms and psychological factors.

METHODS

Data of demographics, the central sensitization inventory (CSI), psychological measures, clinical symptoms of 238 patients with presurgical LBP were evaluated. The patients were divided into two groups depending on the CSI scores (≥40 and < 40). The two groups were compared, and the correlation between the CSI scores and other outcomes was analysed. Furthermore, multiple regression analysis was performed to identify factors contributing to the CSI scores.

RESULTS

13.0% of participants were CSS. All outcomes were significantly different between the groups and significant associations were found between the CSI scores and all other outcomes. In addition, Pain Catastrophizing Scale (PCS) was most significant associated scale for the CSI scores.

CONCLUSION

We found that certain patients had CSS with presurgical LBP. The CSI scores were significantly associated with the majority of the factors. The PCS was the factor with the most influence on the CSI scores.

Central sensitisation in chronic pain conditions: latest discoveries and their potential for precision medicine

Chronic pain is a leading cause of disability globally and associated with enormous health-care costs. The discrepancy between the extent of tissue damage and the magnitude of pain, disability, and associated symptoms represents a diagnostic challenge for rheumatology specialists. Central sensitisation, defined as an amplification of neural signalling within the CNS that elicits pain hypersensitivity, has been investigated as a reason for this discrepancy. Features of central sensitisation have been documented in various pain conditions common in rheumatology practice, including fibromyalgia, osteoarthritis, rheumatoid arthritis, Ehlers-Danlos syndrome, upper extremity tendinopathies, headache, and spinal pain. Within individual pain conditions, there is substantial variation among patients in terms of presence and magnitude of central sensitisation, stressing the importance of individual assessment. Central sensitisation predicts poor treatment outcomes in multiple patient populations. The available evidence supports various pharmacological and non-pharmacological strategies to reduce central sensitisation and to improve patient outcomes in several conditions commonly seen in rheumatology practice. These data open up new treatment perspectives, with the possibility for precision pain medicine treatment according to pain phenotyping as a logical next step. With this view, studies suggest the possibility of matching non-pharmacological approaches, or medications, or both to the central sensitisation pain phenotypes.

Central Sensitization Inventory is a useless instrument for detection of the impairment of the conditioned pain modulation in patients with chronic musculoskeletal pain

OBJECTIVE

The current study aimed to evaluate the concurrent validity and the diagnostic accuracy of the Central Sensitization Inventory (CSI) in detecting the impairment of the pain modulation in patients with chronic musculoskeletal pain.

METHODS

A cross-sectional study was conducted in 267 patients with chronic musculoskeletal pain enrolled consecutively in an outpatient department. The CSI (index method) were compared with the cold pressor test, which was the psychophysical test used to assess the conditioned pain modulation (CPM), (reference standard). Spearman's correlations assessed the concurrent validity, and measurements of the diagnostic accuracy were performed.

RESULTS

Ninety-three (34.8%) patients had CSI scores≥40. No significant correlation was found between CSI findings and the results of the CPT (dorsal forearm site or tibialis anterior site) was found. The cutoff point of 40 of the CSI showed values of sensitivity (35.1%, 95% CI: 22.6, 49.3) and specificity (65.2%, 95% CI: 58.4, 71.6) below 70%, and an accuracy of 59.1 (95% CI: 53.0, 65.1) when compared to the CPT to detect deficit. The ROC curve analysis yielded an area under the curve of 0.54 (95% CI: 0.45, 0.63, P>0.05).

CONCLUSIONS

The CSI is a useless instrument to detect the deficit in the CPM in patients with chronic musculoskeletal pain due to the absence of correlation with the psychophysical test result and the insufficient measurements of diagnostic accuracy.

Assessment of diagnostic criteria for the identification of central sensitization in patients with osteoarthritis pain: Results from a Delphi survey

To assess diagnostic criteria and currently used tools for the identification of central sensitization (CS) in patients with joint pain due to osteoarthritis (OA).Qualitative, cross-sectional and multicenter study based on a 2-round Delphi surveyPublic and private medical centers attending patients with joint pain.A total of 113 specialists in traumatology, physical medicine and rehabilitation, pain management, rheumatology, primary care physicians and geriatrics were enrolled in the study.Participants completed an ad-hoc 26-item questionnaire available from a microsite in Internet.The questionnaire was divided into 6 sections with general data on CS, impact of CS in patients with knee osteoarthritis (KOA), diagnostic criteria for CS, non-pharmacological and pharmacological treatment of CS and usefulness of the concept of CS in the integral management of patients with KOA. Consensus was defined as 75% agreement.Diagnostic criteria included pain of disproportionate intensity to the radiological joint lesion (agreement 86.7%), poor response to usual analgesics (85.8%), progression of pain outside the site of the lesion (76.1%) and concurrent anxiety and depression (76.1%). Based on the opinion of the specialists, about 61% of patients with KOA present moderate-to-severe pain, 50% of them show poor response to conventional analgesics, and 40% poor clinical-radiological correlation. Patients with KOA and CS showed higher functional disability and impairment of quality of life than those without CS (88.5%) and have a poor prognosis of medical, rehabilitation and surgical treatment (86.7%). Early diagnosis and treatment of CS may preserve function and quality of life during all steps of the disease (90.3%).The management of patients with osteoarthritis pain and CS requires the consideration of the intensity of pain related to the joint lesion, response to analgesics, progression of pain to other areas and concurrent anxiety and depression to establish an adequate therapeutic approach based on diagnostic criteria of CS.

Cross-cultural adaptation and validation of the Korean version of the Central Sensitization Inventory in patients undergoing total knee arthroplasty for knee osteoarthritis

The purpose of this study was to establish a Korean version of the Central Sensitization Inventory (CSI-K) for Korean-speaking patients facing total knee arthroplasty (TKA) for knee osteoarthritis (OA) and to investigate the psychometric characteristics of the CSI-K. We recruited a total of 269 patients with knee OA who were scheduled to undergo TKA for the study. CSI-K and pain-related outcomes, including the pain visual analog scale (VAS) and the Western Ontario and McMaster Universities OA Index (WOMAC) pain sub-scores, were measured. Since central sensitization (CS) is closely related to the quality of life (QOL) and limited functionality as well as pain, the patient's function was measured using the WOMAC function sub-scores, and QOL was measured using the EuroQol five-dimension test (EQ-5D). Reliability and validity were evaluated. Exploratory factor analysis (EFA) was conducted to begin the data reduction to validate the existing questionnaire translation. The internal consistency was excellent, with a Cronbach's alpha of 0.941. The test-retest reliability was acceptable-to-excellent with an ICC of 0.888. As expected, the CSI scores correlated strongly with the WOMAC pain scores (r = 0.524, p < 0.001) and moderately with the pain VAS (r = 0.496, p < 0.001), the WOMAC function (r = 0.408, p < 0.001), and the EQ-5D scores (r = 0.437, p < 0.001). EFA resulted in a six-factor model. The findings demonstrate that the CSI was successfully trans-culturally adapted into a simplified Korean version (CSI-K) that was reliable and valid for Korean-speaking patients who awaiting TKA for knee OA.

Effects of Central Sensitivity Syndrome and Psychological Factors on the Clinical Features of Patients with Cervical Degenerative Disease: A Cross-Sectional Study

Study Design

Single-center cross-sectional study.

Purpose

The present study aimed to clarify the effects of central sensitivity syndrome (CSS) and psychological factors on the clinical features in patients with cervical degenerative disease (CDD).

Overview of Literature

The presence of CSS and psychological factors can influence the clinical features of patients with musculoskeletal disorders including CDD. However, the precise effects of CSS are unclear.

Methods

Patients admitted for surgical treatment of CDD were recruited. The following patient-reported outcome measures were recorded on the day before the surgery: the Numerical Rating Scale (NRS) for neck pain intensity, Neck Disability Index (NDI), EuroQol 5-Dimensions (EQ-5D) survey, Central Sensitization Inventory (CSI), Pain Catastrophizing Scale, Tampa Scale for Kinesiophobia, and the Hospital Anxiety and Depression Scale were used. We performed three multiple regression analyses to investigate the effects of CSS and psychological factors on the clinical features.

Results

Multiple regression analysis revealed that CSI had a significant effect on NRS (β, 0.50; 95% confidence interval [CI], 0.29 to 0.71), NDI (β, 0.64; 95% CI, 0.45 to 0.82), and EQ-5D (β, −0.55; 95% CI, −0.75 to −0.35). Multiple regression analysis revealed that psychological factors did not exert a significant effect on the clinical features.

Conclusions

Our results demonstrated that CSI was able to identify the clinical features in CDD patients, suggesting that CSS does affect the clinical features of such patients.

Perioperative intravenous lignocaine infusion for postoperative pain control in patients undergoing surgery of the spine: protocol for a systematic review and meta-analysis

INTRODUCTION

Intravenous lignocaine is an amide local anaesthetic known for its analgesic, antihyperalgesic and anti-inflammatory properties. Administration of intravenous lignocaine has been shown to enhance perioperative recovery parameters. This is the protocol for a systematic review which intends to summarise the evidence base for perioperative intravenous lignocaine administration in patients undergoing spinal surgery.

METHODS AND ANALYSIS

Our primary outcomes include: postoperative pain scores at rest and movement at predefined early, intermediate and late time points and adverse events. Other outcomes of interest include perioperative opioid consumption, composite morbidity, surgical complications and hospital length of stay. We will include randomised controlled trials, which compared intravenous lignocaine infusion vs standard treatment for perioperative analgesia. We will search electronic databases from inception to present; MEDLINE, EMBASE and Cochrane Library (Cochrane Database of Systematic Reviews and CENTRAL). Two team members will independently screen all citations, full-text articles and abstract data. The individual study risk of bias will be appraised using the Cochrane risk of bias tool. We will obtain a risk ratio or mean difference (MD) from the intervention and control group event rates based on the nature of data. We will correct for the variable measurement tools by using the standardised MD (SMD). We will use a random-effects model to synthesise data. We will conduct five subgroup analysis: major versus minor surgery, emergency versus elective surgery, patients with chronic pain conditions versus patients without, duration of lignocaine infusion and adult versus paediatric. Confidence in cumulative evidence for will be classified according to the Grading of Recommendations, Assessment, Development and Evaluation system. We will construct summary of findings tables supported detailed evidence profile tables for predefined outcomes.

ETHICS AND DISSEMINATION

Formal ethical approval is not required as primary data will not be collected. The results will be disseminated through a peer-reviewed publication.

PROSPERO REGISTRATION NUMBER

CRD420201963314.

Central sensitization inventory scores correlate with pain at rest in patients with hip osteoarthritis: a retrospective study

Background

Patients with persistent pain due to osteoarthritis (OA) complain of multiple symptoms that cannot be explained solely by structural changes. A poor correlation exists between structural and inflammatory changes in OA and pain levels. Central sensitization (CS) has been identified as a factor that induces chronic pain in patients with OA. Although it is important to identify osteoarthritis patients with CS components, the prevalence and characteristics of CS, especially those in patients with hip OA, are not well understood. Thus, we aimed to determine the prevalence and characteristics of CS in patients with hip OA, in this study.

Methods

The CS Inventory (CSI), used as a non-invasive routine clinical tool to evaluate the presence of CS 1 month before surgery in 100 patients with hip OA, was measured at our outpatient clinic, and the data were retrospectively reviewed. We determined the number of patients with a CSI score of 40 points or higher and assessed the relationships between the CSI score and clinical factors (including age, duration of hip pain, degree pain at rest and on activity, by using the visual analogue scale [VAS] and the Harris Hip Score) using the Spearman’s correlation coefficient.

Results

The mean age of participants was 63.9 ± 11.6 years, and there were 15 men and 85 women. All patients had hip OA, categorised as advanced and terminal stage (Tönnis grade 2–3) on preoperative plain radiography. The mean duration of hip pain was 4.2 ± 4.4 years. The mean CSI score was 19.5 ± 11.3 and 5 (5.0%) of the patients had a score of 40 or more points. CSI scores correlated significantly only with VAS pain at rest (r = 0.348, P < 0.001).

Conclusion

In this study, 1 out of every 20 hip OA patients had CS components. CSI scores were significantly correlated with pain at rest in hip OApatients. CS approaches to hip OA may be one of the treatment options for pain at rest.

How Does Preoperative Central Sensitization Affect Quality of Life Following Total Knee Arthroplasty?

BACKGROUND

Central sensitization (CS) has been recently identified as a significant risk factor for persistent pain and patient dissatisfaction following total knee arthroplasty (TKA). However, it remains unclear as to whether the preoperative CS persists after the elimination of a nociceptive pain source by TKA, or how CS affects the quality of life after TKA.

METHODS

A total of 222 consecutive patients undergoing primary TKA were enrolled in the study. All patients were preoperatively screened for CS using the Central Sensitization Inventory (CSI) and categorized into either a CS (n = 55; CSI ≥ 40) or non-CS group (n = 167; CSI < 40). CSI, pain visual analog scale (VAS), Knee Society Score (KSS), Western Ontario and McMaster Universities Osteoarthritis Index score, and satisfaction were recorded at postoperative 2 years.

RESULTS

Two years after TKA, preoperative CS remained unchanged; there was no difference between preoperative and postoperative CSI scores, and both preoperative and postoperative CSI severity levels were similar (P > .1). The CS group showed worse pain VAS, KSS, and Western Ontario and McMaster Universities Osteoarthritis Index scores than did the non-CS group (P < .01) and more patients in the CS group were dissatisfied with all activities (P < .01). However, a similar percentage of the CS group achieved the previously documented minimal clinically important difference in pain VAS and KSS, compared with the non-CS group. Multivariate regression analysis revealed that preoperative CSI scores were associated with dissatisfaction at postoperative 2 years.

CONCLUSION

Preoperative CS was persistent at 2 years after TKA. Although CS patients achieved comparable clinical improvement following TKA, CS patients had worse quality of life, functional disability, and dissatisfaction than non-CS patients.

Difference in the impact of central sensitization on pain-related symptoms between patients with chronic low back pain and knee osteoarthritis

Purpose: The aims of the present study were to investigate whether the association between the Central Sensitization Inventory (CSI) score, pain-related symptoms, pain-related disability, and health-related quality of life differed by disease (chronic low back pain [CLBP] vs knee osteoarthritis [KOA]), and to determine optimal cutoff scores for the CSI reflecting disease-specific characteristics.

Patients and methods: A total of 104 patients with CLBP and 50 patients with KOA were recruited. Central sensitization-related symptoms (CSI), EuroQol 5-dimension (EQ-5D), Brief Pain Inventory, widespread pain (Widespread Pain Index [WPI]), pressure pain threshold (PPT), and temporal summation (TS) were assessed and compared between the CLBP and KOA groups. Univariate correlation analysis was performed in each group. The receiver operating characteristic (ROC) curve analysis was performed to identify 1) presence/absence of central sensitization (CS), 2) presence/absence of central sensitivity syndromes (CSSs), and 3) pain intensity and pain interference in each group.

Results: The CSI and WPI scores were significantly higher in the CLBP group than in the KOA group. EQ-5D and pain interference scores significantly correlated with the CSI score in both the CLBP and KOA groups. The WPI score, PPT, and TS did not correlate with the CSI score in either the CLBP or KOA group. The suggested cutoff scores were 28 in the CLBP group and 17 in the KOA group to identify presence or absence of CSSs, and 34 in the CLBP group and 18–19 in the KOA group to identify pain severity.

Conclusion: The impact of CS on pain could differ between CLBP and KOA and that cutoff scores differ by each parameter we attempted to identify. Therefore, we should use the appropriate cutoff scores for the purposes and consider the difference in the impact of CS on pain by the patient group.

Comparison of central sensitization-related symptoms and health-related quality of life between breast cancer survivors with and without chronic pain and healthy controls

BACKGROUND

In breast cancer survivors, multiple risk factors for health-related quality of life (HRQoL) and chronic pain, including cancer treatment-related factors, psychosocial factors, and central sensitization (CS), have been suggested; however, there has been no comparative study between breast cancer survivors with and without pain. This study aimed to compare the demographic characteristics, psychological factors, and CS-related symptoms between breast cancer survivors with pain, those without pain, and healthy controls, and to investigate the relationships of these factors with HRQoL.

METHODS

We conducted a cross-sectional survey of 218 women, including patients who underwent breast cancer surgery and adjuvant therapy and healthy women.

RESULTS

Patients were divided into the pain group (n = 42), without-pain group (n = 51), and healthy group (n = 47); thus, among breast cancer survivors, 45% reported chronic pain. The proportion of participants who received breast cancer treatments, such as axillary lymph node dissection and chemotherapy, was higher in the pain group than in the without-pain group (p < 0.05). The Central Sensitization Inventory (CSI) and psychosocial factors in the pain group were higher than those in the without-pain group and healthy group (p < 0.01). The CSI and PCS showed larger effect sizes than treatment-related factors. Moreover, HRQoL was significantly correlated with CSI, PCS, Patient Health Questionnaire-2, and Generalized Anxiety Disorder-2 scale (all, p < 0.01). On multiple linear regression analysis, CSI accounted for 43% of the variance in HRQoL.

CONCLUSIONS

CS and pain catastrophizing may be more associated with the development and/or maintenance of persistent pain than treatment-related factors.

Development and psychometric properties of short form of central sensitization inventory in participants with musculoskeletal pain: A cross-sectional study

Background

The central sensitization inventory (CSI) comprises 25 items and is commonly used to measure somatic and emotional symptoms related to central sensitization symptoms. CSI was developed as an easy-to-administer screening instrument for patients at high risk of developing central sensitization in whom it was essential to quickly evaluate the condition. The purpose of the present study was to develop a short form of CSI and evaluate its psychometric properties using a contemporary approach called Rasch analysis.

Methods

A total of 505 patients with musculoskeletal disorders were recruited in this study. The CSI, pain intensity, pain interference, and the health-related quality of life (QOL) were evaluated for each participant. The original CSI items were consecutively analyzed using the Rasch model. Successive Rasch analyses were performed until a final set of items satisfied the model fit requirements. We also analyzed the psychometric properties of the original and short forms of CSI.

Results

Four consecutive Rasch analyses identified the removable items. Finally, the shortest questionnaire obtained that maintained the correct psychometric properties based on the Rasch model contained only 9 items (CSI-9). Rasch analysis showed that the CSI-9 had acceptable internal consistency, exhibited unidimensionality, had no notable differential item functioning, and was functional on the category rating scale.

Conclusions

The nine-item short form of CSI has acceptable psychometric properties and is suitable for use for patients with musculoskeletal pain. Thus, the CSI-9 can be used as a brief instrument to evaluate central sensitization.