The reliability of clinical judgments and criteria associated with mechanisms-based classifications of pain in patients with low back pain disorders: a preliminary reliability study

Abstract

Mechanisms-based classifications of pain have been advocated for their potential to aid understanding of clinical presentations of pain and improve clinical outcomes. However, the reliability of mechanisms-based classifications of pain and the clinical criteria upon which such classifications are based are not known. The purpose of this investigation was to assess the inter-and intra-examiner reliability of clinical judgments associated with: (i) mechanisms-based classifications of pain; and (ii) the identification and interpretation of individual symptoms and signs from a Delphi-derived expert consensus list of clinical criteria associated with mechanisms-based classifications of pain in patients with low back (¡leg) pain disorders. The interand intra-examiner reliability of an examination protocol performed by two physiotherapists on two separate cohorts of 40 patients was assessed. Data were analysed using kappa and percentage of agreement values. Inter-and intra-examiner agreement associated with clinicians' mechanisms-based classifications of low back (¡leg) pain was 'substantial' (kappa 50.77; 95% confidence interval (CI): 0.57-0.96; % agreement 587.5) and 'almost perfect' (kappa 50.96; 95% CI: 0.92-1.00; % agreement592.5), respectively. Sixty-eight and 95% of items on the clinical criteria checklist demonstrated clinically acceptable (kappa > 0.61 or % agreement > 80%) inter-and intra-examiner reliability, respectively. The results of this study provide preliminary evidence supporting the reliability of clinical judgments associated with mechanisms-based classifications of pain in patients with low back (¡leg) pain disorders. The reliability of mechanisms-based classifications of pain should be investigated using larger samples of patients and multiple independent examiners.

Reliability among clinicians diagnosing low back-related leg pain

“…These systems are based on specific algorithms which possibly make it easier to agree on categories [12,22]. This study reflects current clinical practice where an overall clinical impression is made based on the signs and symptoms.…”

“…The number of patients recruited in this reliability study is similar to the majority of published reliability studies on LBP classification systems [12,22]. However, the sample size calculation is based on specifying a zero value for kappa in the null hypothesis.…”

“…Reliability of individual clinical tests to identify NRI has been documented as mainly poor [6] and agreement on self-reported features of NRI has generally not shown better than fair reliability [11,12]. However, the reliability of the overall decision as to whether a clinical presentation in LBLP patients is NRI or referred pain has received less attention.…”

Validation of a pain mechanism classification system (PMCS) in physical therapy practice

“…[8][9][10] Pain mechanism classification systems (PMCSs) have been introduced into the diagnostic process for pain practitioners such as physical therapists (PTs) and physicians. [11][12][13] The clinical indicators of nociceptive, peripheral neuropathic, and central mechanisms have been used to classify patients' reports of pain.…”

“…A preliminary inter-and intraexaminer reliability study concluded that two therapists reliably diagnosed the dominant pain mechanism of patients with low back and leg pain, but concluded that a study with a larger sample of patients with multiple independent examiners was needed. 12 Evidence for discriminative validity of the classification system was established for categories of nociceptive, peripheral neuropathic, and central sensitization with a larger population of patients. 13 The PMCS described by Gifford and Butler 19 was modified and implemented into PT practice within the outpatient clinics of a rehabilitation hospital during the last 11 years.…”