Assessment of Ankylosing Spondylitis Criteria in Patients with Chronic Low Back Pain and Vertebral Endplate Modic I Signal Changes

Abstract

Objective.Patients with chronic low back pain (cLBP) and vertebral endplate Modic I signal changes on lumbar magnetic resonance imaging (MRI) have clinical features that could mimic inflammatory back pain related to spondyloarthritis (SpA) and/or ankylosing spondylitis (AS). We aimed to assess whether such patients fulfilled criteria for SpA and/or AS.Methods.For 5 months in 2008, all patients (n = 314) referred to a tertiary care physical medicine and rehabilitation facility in France were consecutively screened. A total of 185 hospitalized for non-specific cLBP were prospectively assessed. Forty patients fulfilling inclusion criteria were consecutively enrolled and included in 2 groups according to MRI findings: Modic I (n = 15) and non-Modic I (n = 25). MRI findings were assessed independently by 2 spine specialists and a radiologist. HLA-B27 status was determined. Data were collected on clinical measurements and fulfillment of Amor criteria (AC) and modified New York criteria (mNYC). All assessors were blinded to HLA-B27 status.Results.Whatever the Modic group, no patient fulfilled AC or mNYC, and mean total scores were comparable [3 ± 2 (range 0–22; p = 0.977), 1 ± 1 (range 0–3; p = 1.000), and 0 ± 0 (range 0–1; p = 1.000) for AC and clinical and radiological mNYC, respectively]. HLA-B27 status was similar in both groups [n = 2 (13%) vs n = 0 (0%); p = 0.135].Conclusion.Patients with cLBP and Modic I vertebral endplate signal changes on lumbar MRI do not fulfill widely used and validated criteria for SpA and/or AS. Such cases are clinically distinct from SpA and AS.