Biomarkers and longitudinal changes in lumbar spine degeneration and low back pain: the Johnston County Osteoarthritis Project.

OBJECTIVE: To determine if baseline biomarkers are associated with longitudinal changes in the worsening of disc space narrowing (DSN), vertebral osteophytes (OST), and low back pain (LBP). DESIGN: Paired baseline (2003-2004) and follow-up (2006-2010) lumbar spine radiographs from the Johnston County Osteoarthritis Project were graded for severity of DSN and OST. LBP severity was self-reported. Concentrations of analytes (cytokines, proteoglycans, and neuropeptides) were quantified by immunoassay. Pressure-pain threshold (PPT), a marker of sensitivity to pressure pain, was measured with a standard dolorimeter. Binary logistic regression models were used to estimate odd ratios (OR) and 95% confidence intervals (CI) of biomarker levels with DSN, OST, or LBP. Interactions were tested between biomarker levels and the number of affected lumbar spine levels or LBP. RESULTS: We included participants (n = 723) with biospecimens, PPT, and paired lumbar spine radiographic data. Baseline Lumican, a proteoglycan reflective of extracellular matrix changes, was associated with longitudinal changes in DSN worsening (OR = 3.19 [95% CI 1.22, 8.01]). Baseline brain-derived neuropathic factor, a neuropeptide, (OR = 1.80 [95% CI 1.03, 3.16]) was associated with longitudinal changes in OST worsening, which may reflect osteoclast genesis. Baseline hyaluronic acid (OR = 1.31 [95% CI 1.01, 1.71]), indicative of systemic inflammation, and PPT (OR = 1.56 [95% CI 1.02, 2.31]) were associated with longitudinal increases in LBP severity. CONCLUSION: These findings suggest that baseline biomarkers are associated with longitudinal changes occurring in structures of the lumbar spine (DSN vs OST). Markers of inflammation and perceived pressure pain sensitivity were associated with longitudinal worsening of LBP.

Effects of functional taping compared with sham taping and minimal intervention on pain intensity and static postural control for patients with non-specific chronic low back pain: a randomised clinical trial protocol.

OBJECTIVES: To investigate the immediate and 1-month effects of functional taping to lumbar spine for pain intensity and postural control in patients with chronic non-specific low back pain. DESIGN: Randomised clinical trial. PARTICIPANTS: One hundred and twenty participants aged 18 to 50 years. INTERVENTIONS: Participants will be allocated at random to receive one of three interventions: functional star-shape taping for 7 days, sham functional taping for 7 days or minimal intervention, one session. MAIN OUTCOME MEASURES: The primary outcomes will be pain intensity and postural control. Four measurements of static posturography will be conducted: pre-intervention, immediately after application of the tape, 7 days post-intervention (after removal of the tape) and 1-month follow-up. The secondary outcomes will be low-back-pain-related disability, global perceived effect of treatment and fear avoidance beliefs. Primary and secondary outcomes will be assessed on three occasions: pre-intervention, 7 days post-intervention and at 1-month follow-up. All statistical analyses will be conducted following intention-to-treat principles, and the treatment effects will be calculated using linear mixed models. DISCUSSION: The results of this study will determine the effects of functional taping on pain intensity and postural control compared with sham taping and minimal intervention. CLINICAL TRIAL REGISTRATION NUMBER: NCT02546466.

Temporal summation of second pain: variability in responses to a fixed protocol.

BACKGROUND: Temporal summation of second pain (TSSP) is relevant for the study of central sensitization, and refers to increased pain evoked by repetitive stimuli at a constant intensity. While the literature reports on participants whose pain ratings increase with successive stimuli, response to a TSSP protocol can be variable. The aim of this study was to characterize the full range of responses to a TSSP protocol in pain-free adults. METHOD: Three hundred twelve adults received a train of brief, repetitive heat stimuli at a fixed temperature and rated the intensity of second pain after each pulse. TSSP response (Δ in pain ratings) was quantified using the most common methods in the literature, and response groups were formed: TSSP (Δ > 0), no change (Δ = 0), and temporal decrease in second pain (TDSP) (Δ < 0). A cluster analysis was performed on the Δ values to empirically derive response groups. RESULTS: Depending on how TSSP response was quantified, 61-72% of the sample demonstrated TSSP, 11-28% had no change in pain ratings and 0-20% demonstrated TDSP. The cluster analysis found that the majority (59%) of participants fell in the no change cluster, 29% clustered into the TSSP group and 12% in the TDSP cluster. CONCLUSIONS: Using a fixed thermal paradigm, pain-free adults exhibit substantial variability in response to a TSSP protocol not well characterized by group-mean slopes. Studies are needed to determine TSSP response patterns in clinical samples, identify predictors of response and determine the clinical implications of response variability.

A comparison of fear-avoidance beliefs in patients with lumbar spine pain and cervical spine pain.

STUDY DESIGN: A prospective consecutive cohort study of patients with cervical spine pain and patients with lumbar spine pain referred to an academic medical center. OBJECTIVES: To investigate the presence of fear-avoidance beliefs in a sample of patients with cervical spine pain and to compare the association of pain intensity, disability, and fear-avoidance beliefs in patients with cervical spine pain with that in patients with lumbar spine pain. SUMMARY OF BACKGROUND DATA: Fear-avoidance beliefs are a specific psychosocial variable involved in the development of disability from low back pain. Psychosocial variables are believed to play a role in cervical disability, but specific variables have not been investigated. METHODS: Consecutive patients referred to a multidisciplinary center completed self-reports of disability, pain intensity, and fear-avoidance beliefs during an initial evaluation session. Gender, type of symptom onset, acuity, and payer source were also recorded. Associations between disability, pain intensity, and fear-avoidance beliefs were investigated in patients with cervical spine pain and patients with lumbar spine pain. RESULTS: In all, 163 patients completed the self-reports and were included in this study. Weaker relations between fear-avoidance beliefs and disability were found in patients with cervical pain than in those with lumbar pain. Significant differences in fear-avoidance beliefs were found for gender, type of symptom onset, and payer source (workers' compensation, auto insurance, and traditional insurance). CONCLUSION: The associations among fear-avoidance beliefs, pain intensity, and disability differed between patients with cervical spine pain and patients with lumbar spine pain. Fear-avoidance beliefs were significantly different in subgroups of patients.