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Agreement of self-reported items and clinically assessed nerve root involvement (or sciatica) in a primary care setting

updated

Tags: diagnosis, sciatica, back pain, pain problems, spine, butt, hip

Three articles on PainSci cite Konstantinou 2012: (1) A Guide to Sciatica Treatment for Patients(2) Complete Guide to Low Back Pain(3) The Complete Guide to Neck Pain & Cricks

PainSci summary of Konstantinou 2012: ?This page is one of thousands in the PainScience.com bibliography. It is not a general article: it is focused on a single scientific paper, and it may provide only just enough context for the summary to make sense. Links to other papers and more general information are provided at the bottom of the page, as often as possible.

Patient descriptions like “pain below the knee,” “radiating pain in the legs,” “pain running down the leg,” have always been considered indicators of sciatica (radiculopathy caused by nerve root compression). Do any of these common phrases actually identify sciatica? Unfortunately not: in this study of more than 500 back pain patients with pain radiating to the legs, no single self-report, or cluster of them, was clearly associated with cases of sciata identified by careful history and exam. “Pain below the knee” was the closest match, but it was still misleading: not every patient with sciatica has that symptom, and some with that symptom do not have sciatica. Similarly, a cluster of descriptions including “distribution of pain below the knee,” “leg pain that is worse than back pain,” and “feeling of numbness or pins and needles in the leg” also correctly identified many cases, but still misclassified too many.

Certain self-report indicators particularly pain radiating below, leg pain worse than back pain, and numbness, pins and needles in the leg can be useful at a very crude level. However, when accuracy in case definition is of importance, clinical examination is the recommended method.

~ Paul Ingraham

original abstract Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.

INTRODUCTION: We analysed baseline measures from an RCT involving adults with low back pain (LBP) with or without referred leg pain, to identify self-report items that best identified clinically determined nerve root involvement (sciatica).

METHODS: Potential indicators of nerve root involvement were gathered using a self-reported questionnaire. Participants underwent a standardised physical examination on the same day as questionnaire completion. Self-reported items were compared to a reference standard (clinical diagnosis) using sensitivity, specificity, predictive values, likelihood ratios (LRs), the area under the receiver operating characteristic curve and logistic regression. Two reference standards are presented: one based on a clinical diagnosis of nerve root problems and excluding possible/inconclusive cases (referred to as a confirmatory reference), and the other being inclusive of possible/inconclusive cases (referred to as an indicative reference).

RESULTS: Pain below knee was the best single item for diagnostic accuracy with an area under curve (AUC) of 0.67-0.68, which however is slightly less than the 'acceptable discrimination'. A cluster of three items, including distribution of pain below the knee, leg pain that is worse than back pain, and feeling of numbness or pins and needles in the leg, did improve discrimination to an 'acceptable' level with an AUC of 0.72-0.74 in relation to confirmatory and indicative references, respectively. However, the likelihood ratios from the models were reflective of a 'small' amount of discrimination.

CONCLUSION: In this primary care population seeking treatment for LBP with or without leg pain, we found no clear set of self-report items that accurately identified patients with nerve root pain. When accurate case definition is important, clinical assessment should be the method of choice for identifying LBP with possible nerve root involvement.

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