Lumbar Isthmic Spondylolisthesis Detection with Palpation: Interrater Reliability and Concurrent Criterion-Related Validity

Abstract

Lumbar spinous process palpation to detect spondylolisthesis is a technique frequently used by clinicians and taught in professional education courses, but it has not been shown to be reliable or valid. The purpose of this study was to assess the diagnostic utility of lumbar spinous palpation as a means of detecting isthmic spondylolisthesis in patients with low back pain. Interrater reliability was assessed by pair-wise comparison of the findings of three therapists palpating the spinous processes on 30 subjects with low back pain. Validity was evaluated by comparing the findings of one therapist to a reference standard of plain film radiographs in 44 patients. The pair-wise kappa values were poor to fair at 0.179, 0.394, and 0.314. Validity testing revealed a sensitivity of 60% (95% CI, 14.7-94.7) and a specificity of 87.2% (95% CI, 72.6-95.7%). The positive likelihood ratio was 4.68 (95% confidence interval (CI): 1.57-13.88) and the negative likelihood ratio was 0.458 (95% CI, 0.155-1.35). Both likelihood ratios produced only a small change in pre- to post-test probabilities. Based on our results, static spinous process palpation by itself is not a definitive method for the detection of spondylolisthesis. However, the study data do not preclude the possible future use of palpation along with other, yet to be identified, validated predictive variables for isthmic spondylolisthesis.

Keywords:

• PHYSICAL EXAMINATION
• LOW BACK PAIN
• INTERRATER RELIABILITY
• SENSITIVITY
• SPECIFICITY
• LIKELIHOOD RATIO
• DIAGNOSTIC IMAGING