Maximal cardiopulmonary exercise test in patients with chronic low back pain: feasibility, tolerance and relation with central sensitization. An observational study:feasibility, tolerance and relation with central sensitization. An observational study

PURPOSE: To analyze the feasibility of and pain-related tolerance to a maximal cardiopulmonary exercise test (CPET), and the relationship between the aerobic capacity and central sensitization (CS) in patients with chronic low back pain (CLBP).METHODS: An observational study, combining a cross-sectional and a prospective 24-hour follow-up was performed. Participants underwent a maximal CPET on a cycle ergometer and were assessed with three measures of CS (CS Inventory, quantitative sensory testing and heart rate variability). Before the CPET, immediately afterwards and 24 h after, the Pain Response Questionnaire (PRQ) was filled out. The CPET was considered feasible when &gt;80% performed maximally, and tolerable when &lt;20% reported relevant pain increase, body reactions and additional pain medication use in the PRQ. Multiple regression analyses were applied to assess the relationship between the aerobic capacity (VO2max) and CS measures, corrected for confounders.RESULTS: 74 patients with CLBP participated of which 30 were male, mean age was 40.4 years (SD: 12.4) and median VO2max was 23.9 ml/kg/min (IQR: 18.2-29.4). CPET was completed by 92%. No serious adverse events occurred. A relevant pain increase was reported in the upper legs by 40% immediately after CPET and by 28% 24 h afterwards, 27% reported body reactions after 24 h, and 22% increased pain medication use 24 h after CPET. Very weak and not significant relations (rpartial=-0.21 to 0.05; p &gt; 0.10) were observed between aerobic capacity and CS measures.CONCLUSIONS: A maximal CPET is feasible in patients with CLBP. Most, but not all, tolerated it well. CS was not related to aerobic capacity.Implications for rehabilitationMaximal CPET is feasible in patients with CLBP and well tolerated by most patients.Maximal CPET can be safely applied to assess the aerobic capacity of patients with CLBP.Aerobic capacity is unrelated to central sensitization.Outcomes of a maximal CPET and the pain response to straining activity can be used to provide valid information for the decision-making of exercise therapy.</p

Association between central sensitization and gait in chronic low back pain:Insights from a machine learning approach

BACKGROUND: Central sensitization (CS) is often present in patients with chronic low back pain (CLBP). Gait impairments due to CLBP have been extensively reported; however, the association between CS and gait is unknown. The present study examined the association between CS and CLBP on gait during activities of daily living. METHOD: Forty-two patients with CLBP were included. CS was assessed through the Central Sensitization Inventory (CSI), and patients were divided in a low and high CS group (23 CLBP- and 19 CLBP+, respectively). Patients wore a tri-axial accelerometer device for one week. From the acceleration signals, gait cycles were extracted and 36 gait outcomes representing quantitative and qualitative characteristics of gait were calculated. A Random Forest was trained to classify CLBP- and CLBP + based on the gait outcomes. The maximum Youden index was computed to measure the diagnostic test's ability and SHapley Additive exPlanations (SHAP) indexed the gait outcomes' importance to the classification model. RESULTS: The Random Forest accurately (84.4%) classified the CLBP- and CLBP+. Youden index was 0.65, and SHAP revealed that the gait outcomes' important to the classification model were related to gait smoothness, stride frequency variability, stride length variability, stride regularity, predictability, and stability. CONCLUSIONS: CLBP- and CLBP + patients had different motor control strategies. Patients in the CLBP- group presented with a more "loose control", with higher gait smoothness and stability, while CLBP + patients presented with a "tight control", with a more regular, less variable, and more predictable gait pattern

Validity of the Central Sensitization Inventory to Address Human Assumed Central Sensitization:Newly Proposed Clinically Relevant Values and Associations

Central sensitization cannot be directly demonstrated in humans and thus a gold standard is missing. Therefore, we used human assumed central sensitization (HACS) when associated with humans. The central sensitization inventory (CSI) is a screening questionnaire for addressing symptoms that are associated with HACS. This cross-sectional study compared patients with chronic pain and at least one central sensitivity syndrome with healthy, pain-free controls via ROC analyses. Analyses were performed for all participants together and for each sex separately. Regression analyses were performed on patients with chronic pain with and without central sensitivity syndromes. Based on 1730 patients and 250 healthy controls, cutoff values for the CSI for the total group were established at 30 points: women: 33 points; men: 25 points. Univariate and multivariate regression analyses were used to identify possible predictors for the CSI score in 2890 patients with chronic pain. The CSI score is associated with all independent factors and has a low association with pain severity in women and a low association with pain severity, age, and body mass index in men. The newly established CSI cutoff values are lower than in previous studies and different per sex, which might be of clinical relevance in daily practice and importance in research.</p

Multifactoriële analyse in de medisch-specialistische revalidatie

Als een patiënt met chronische pijn wordt verwezen naar de revalidatiearts dan kan er sprake zijn van laag complexe of hoog complexe problematiek. Interdisciplinaire behandeling in de medisch-specialistische revalidatie (MSR) is alleen geïndiceerd bij hoog-complexe problematiek. Bij de vaststelling van de mate van complexiteit van het pijnprobleem maakt de revalidatiearts gebruik van verwijsinformatie (correspondentie, eerder verrichte diagnostiek), neemt een uitgebreide anamnese af, eventueel gecombineerd met korte vragenlijsten, verricht lichamelijk onderzoek en laat zo nodig zelf aanvullende diagnostiek verrichten. Als er voldoende informatie is verzameld, begint het proces van analyse. Voor analyse wordt gebruik gemaakt van de zogenaamde ‘vlaggen’, waarbij de aanwezigheid van rode vlaggen kan wijzen op onderliggende (ernstige) somatische problematiek en de overige vlaggen (geel, oranje, blauw, zwart) te beschouwen zijn als prognostisch relevante factoren. Daarnaast wordt gebruik gemaakt van het exploreren van predisponerende, uitlokkende en onderhoudende factoren als hulpmiddel bij de analyse, waarbij met name de laatste van groot belang zijn voor het bepalen van mogelijke aangrijpingspunten van behandeling. Zo komt de revalidatiearts tot een indicatiestelling voor een interventie en aangrijpingspunten voor behandeling. In dit hoofdstuk worden de predisponerende, uitlokkende en onderhoudende factoren besproken. Onderhoudende factoren kunnen biomedisch, psychologisch en/of sociaal zijn en al deze worden factoren worden uitgebreid toegelicht. Er wordt speciaal aandacht geschonken aan de mogelijk negatieve beïnvloeding door medewerkers uit het (para en peri-)medische circuit

Relationship between physical activity and central sensitization in chronic low back pain: Insights from machine learning

Background and objectives: Chronic low back pain (CLBP) is a leading cause of disability. The management guidelines for the management of CLBP often recommend optimizing physical activity (PA). Among a subsample of patients with CLBP, central sensitization (CS) is present. However, knowledge about the association between PA intensity patterns, CLBP, and CS is limited. The objective PA computed by conventional approaches (e.g. cut-points) may not be sensitive enough to explore this association. This study aimed to investigate PA intensity patterns in patients with CLBP and low or high CS (CLBP-, CLBP+, respectively) by using advanced unsupervised machine learning approach, Hidden semi-Markov model (HSMM). Methods: Forty-two patients were included (23 CLBP-, 19 CLBP+). CS-related symptoms (e.g. fatigue, sensitivity to light, psychological features) were assessed by a CS Inventory. Patients wore a standard 3D-accelerometer for one week and PA was recorded. The conventional cut-points approach was used to compute the time accumulation and distribution of PA intensity levels in a day. For the two groups, two HSMMs were developed to measure the temporal organization of and transition between hidden states (PA intensity levels), based on the accelerometer vector magnitude. Results: Based on the conventional cut-points approach, no significant differences were found between CLBP- and CLBP+ groups (p = 0.87). In contrast, HSMMs revealed significant differences between the two groups. For the 5 identified hidden states (rest, sedentary, light PA, light locomotion, and moderate-vigorous PA), the CLBP- group had a higher transition probability from rest, light PA, and moderate-vigorous PA states to the sedentary state (p < 0.001). In addition, the CBLP- group had a significantly shorter bout duration of the sedentary state (p < 0.001). The CLBP+ group exhibited longer durations of active (p < 0.001) and inactive states (p = 0.037) and had higher transition probabilities between active states (p < 0.001). Conclusions: HSMM discloses the temporal organization and transitions of PA intensity levels based on accelerometer data, yielding valuable and detailed clinical information. The results imply that patients with CLBP- and CLBP+ have different PA intensity patterns. CLBP+ patients may adopt the distress-endurance response pattern with a prolonged bout duration of activity engagement