A Screening Tool for Patients With Lumbar Instability

Study Design. The study is a cross-sectional, diagnostic validity study. Objective. The aim of this study was to examine the performance characteristics and validity of an existing lumbar instability questionnaire as a screening tool for lumbar instability among chronic low back pain (CLBP) patients. Summary of Background Data. Lumbar instability is an initial stage of more severe spinal pathology. Early screening for this condition should help prevent more structural damage. To meet this need, the present study developed numerical cutoff scores for the lumbar instability screening tool. Methods. Lumbar instability screening tool responses and x-ray assessments were reviewed from a sample of 110 patients with CLBP (aged 20–59 years). Receiver operator curves were constructed to optimize sensitivity and specificity of the tool. Results. Fourteen (12.73%) patients had radiological lumbar instability. These patients reported a higher mean lumbar instability questionnaire score than those without radiological lumbar instability. A questionnaire score of at least 7 had a sensitivity of 100% (95% CI, 100–100) and a specificity of 26.04% (95% CI = 17.84–34.24) for detecting lumbar instability when compared with x-ray examination. Receiver operator curve analysis revealed the lumbar instability screening had an area under the curve of 0.62 (95% CI, 0.47–0.77). Conclusion. A lumbar instability screening tool total score of at least 7 was ruled out lumbar instability in CLBP patients. This cutoff score may be used as a marker of conservative treatment response. The sample size of patients with lumbar instability in this study was small, which may hinder the reliability of the data. Further studies are needed. Level of Evidence: 4