Background Neck and low back pain represent dynamic conditions that change over time, often with an initial improvement after the onset of a new episode, followed by flare-ups or variations in intensity. Pain trajectories were previously defined based on longitudinal studies of temporal patterns and pain intensity of individuals with low back pain. In this study, we aimed to 1) investigate if the defined patterns and subgroups for low back pain were applicable to neck pain patients in chiropractic practice, 2) explore the robustness of the defined patterns, and 3) investigate if patients within the various patterns differ concerning characteristics and clinical findings. Methods Prospective cohort study including 1208 neck pain patients from chiropractic practice. Patients responded to weekly SMS-questions about pain intensity and frequency over 43 weeks. We categorized individual responses into four main patterns based on number of days with pain and variations in pain intensity, and subdivided each into four subgroups based on pain intensity, resulting in 16 trajectory subgroups. We compared baseline characteristics and clinical findings between patterns and between Persistent fluctuating and Episodic subgroups. Results All but two patients could be classified into one of the 16 subgroups, with 94% in the Persistent fluctuating or Episodic patterns. In the largest subgroup, “Mild Persistent fluctuating” (25%), mean (SD) pain intensity was 3.4 (0.6) and mean days with pain 130. Patients grouped as “Moderate Episodic” (24%) reported a mean pain intensity of 2.7 (0.6) and 39 days with pain. Eight of the 16 subgroups each contained less than 1% of the cohort. Patients in the Persistent fluctuating pattern scored higher than the other patterns in terms of reduced function and psychosocial factors. Conclusions The same subgroups seem to fit neck and low back pain patients, with pain that typically persists and varies in intensity or is episodic. Patients in a Persistent fluctuating pattern are more bothered by their pain than those in other patterns. The low back pain definitions can be used on patients with neck pain, but with the majority of patients classified into 8 subgroups, there seems to be a redundancy in the original model.

Study Design. A prospective observational study. Objective. To externally validate the prediction model developed by Schellingerhout and colleagues predicting global perceived effect at 12 weeks in patients with neck pain and to update and internally validate the updated model. Summary of Background Data. Only one prediction model for neck pain has undergone some external validation with good promise. However, the model needs testing in other populations before implementation in clinical practice. Methods. Patients with neck pain (n ¼ 773) consulting Norwegian chiropractors were followed for 12 weeks. Parameters from the original prediction model were applied to this sample for external validation. Subsequently, two random samples were drawn from the full study sample. One sample (n ¼ 436) was used to update the model; by recalibration, removing noninformative covariates, and adding new possible predictors. The updated model was tested in the other sample (n ¼ 303) using stepwise logistic regression analysis. Main outcomes for performance of models were discrimination and calibration plots. Results. Three hundred seventy patients (47%) in the full study sample reported persistent pain at 12 weeks. The performance of the original model was poor, area under the receiver operating characteristics curve was 0.55 with a Confidence Interval of 0.51-0.59. The updated model included Radiating pain to shoulder and/or elbow, education level, physical activity, consultation-type (first-time, follow-up or maintenance consultation), expected course of neck pain, previous course of neck pain, number of pain sites, and the interaction term Physical activity##Number of pain sites. The area under the receiver operating characteristics curve was 0.65 with a 95% Confidence Interval of 0.58-0.71 for the updated model. Conclusion. The predictive accuracy of the original model performed insufficiently in the sample of patients from Norwegian chiropractors and the model is therefore not recommended for that setting. Only one predictor from the original model was retained in the updated model, which demonstrated reasonable good performance predicting outcome at 12 weeks. Before considering clinical use, a new external validation is required.

BackgroundThe reliability of musculoskeletal diagnostic ultrasound imaging (MSK-DUSI) for the evaluation of neck musculature has been sparsely documented in the research literature. Until now, research has featured a limited number of subjects and only few studies have tested for both inter- and intra-reliability using appropriate methodology.MethodsFour examiners conducted an inter- and intra-rater reliability and agreement study. Fifty females with and without neck pain (NP) between the ages of 20–70 were recruited from October 2014 to April 2015. The muscles that were evaluated were the longus colli (Lcol), the rectus capitis posterior major (Rcpm), the deep cervical extensors (Dce) and the semispinalis capitis (Sscap). Each of the examiners captured ultrasound images of their allocated muscle and measured the thickness of that muscle twice, on separate occasions, for the first part of the intra-rater reliability study. For the second part, a second image of the same muscle was taken on the same subject and measured by the same examiner. The four examiners then met to measure on each other’s images, to test inter-rater reliability. Their results were compared pair-wise using Interclass Correlation Coefficients (ICC) and Bland-Altman plots. Linear regression analysis was performed to evaluate for possible bias.ResultsInter-rater reliability was found to be good for Lcol and Sscap muscles and moderate towards poor for the deeper Rcpm and Dce muscles. Intra-rater reliability was good for all the muscles, with the exception of the Dce, which was found to be moderate in the second part of the study. The B&A plots showed good agreement, few outliers, and no bias. However, the agreement intervals indicated a measurement error within the variance of the method that may not have been acceptable for these small muscles if the aim is to evaluate change in thickness.ConclusionsThis study found that MSK-DUSI had variable reliability in assessing the thickness of the Lcol, Rcpm, Dce, and Sscap muscles. No bias was demonstrated, but agreement intervals were wide.

Background A novel approach capturing both temporal variation and pain intensity of neck pain is by visual trajectory patterns. Recently, both previous and expected visual trajectory patterns were identified as stronger predictors of outcome than traditional measures of pain history and psychological distress. Our aim was to examine patient characteristics within the various previous and expected patterns, relationship between the two patterns and predictive value of a variable combining the previous and expected patterns. Methods Patients with neck pain (n = 932) consulting chiropractors were included. Baseline measures included pain intensity, disability, psychological variables and symptom history and expectations. Participants reported global perceived effect after 12 weeks. Analyses included descriptive statistics and logistic regression. Results Pain intensity, disability, psychological and worse outcome expectations increased from a single pain episode to severe ongoing pain of previous and expected patterns. Having a severe pain history was associated with poor prognosis, particularly if combined with negative expectations. The variable combining previous and expected patterns had a discriminative ability similar to that of other predictors AUC = 0.64 (95% CI = 0.60–0–67) versus AUC = 0.66 (95% CI = 0.62–0.70). The model with highest discriminative ability was achieved when adding the combined patterns to other predictors AUC = 0.70 (95% CI = 0.66–0.73). Conclusion The study indicates that pain expectations are formed by pain history. The patients’ expectations were similar to or more optimistic compared with their pain history. The prognostic ability of the model including a simplified combination of previous and expected patterns, together with a few other predictors, suggests that the trajectory patterns might have potential for clinical use. Significance The dynamic nature of neck pain can be captured by visual illustrations of trajectory patterns. We report, that trajectory patterns of pain history and future expectations to some extent are related. The patterns also reflect a difference in severity assessed by higher degree of symptoms and distress. Moreover, the visual trajectory patterns predict outcome at 12‐weeks. Since the patterns are easily applicable, they might have potential as a clinical tool.

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