Posted on Sep 01, 2020
Evidence-based Diagnosis for Low Back Pain
By Robert Vining, DC
Health professionals from different disciplines use diverse diagnostic methods to inform clinical management for patients with low back pain.1 One person may diagnose someone as suffering from sacroiliac joint pain while another might classify the same patient with a movement disorder caused by poor muscle coordination. In a given circumstance, either or both individuals could be right or wrong. However, we can’t realistically discern this until we understand the underlying strength of the diagnostic tests we use.
Part of the problem with diagnosis of spinal conditions in general is terminology. Diagnoses for low back pain are often little more than a repetition of symptoms. For example, common diagnoses include “low back pain,” “lumbalgia,” “mechanical low back pain,” and “non-specific low back pain.”2 These terms are often used because it is difficult to definitively determine a single pain source or cause. The reasons for this problem include:
- varied and conflicting terminology used to describe identical conditions;
- few, if any, diagnostic tests that conclusively identify individual diagnoses;
- multiple conditions that can cause similar or identical symptoms simultaneously; and
- the challenge of understanding how psychological and social factors influence symptoms.
To inform management decisions and differentiate benign from ominous conditions, we need to consistently identify a symptom source with a reasonable degree of confidence.3;4 However, we are hampered if we don’t understand how much to depend on the information used to reach a diagnosis. To address these issues, I led a team of researchers in developing an evidence-based diagnostic classification system for low back pain.5 The classification system is not original research. Rather, it is a synthesis of a large number of clinical studies on the topic of diagnosis, especially those evaluating office-based examination procedures.
Diagnosis of most non-visceral, non-malignant, and non-infections primary low back pain falls into two broad categories, 1) nociceptive, and 2) neuropathic. Nociceptive pain arises from inflammation and/or damage to tissues where nociceptors are located (intervertebral discs, facet joints, sacroiliac joints, muscles and fascia). Neuropathic pain is caused by dysfunction within the peripheral or central nervous system causing pain to arise from nerve trunks rather than nerve endings (compressive and non-compressive radiculopathy, and neurogenic claudication), or augmented pain through sensitization.
Along with the classification system, we developed a checklist that helps standardize terminology, generate diagnoses based on research evidence, and avoid opinion-based diagnostic reasoning errors. The checklist contains criteria for identifying each diagnostic category. For example, clinical research has generally confirmed that centralization with repeated motion is an in-office test and finding that can identify patients likely suffering from discogenic pain (pain from an intervertebral disc). Other diagnostic criteria, when met, suggest patients likely suffer from other diagnoses. There is enough evidence available now for us to begin moving toward research-based diagnosis, which reduces subjectivity and should improve communication between providers, and with payers and patients.
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