Reliability and diagnostic accuracy of the clinical tests for lumbar instability: a systematic review

Study design: Systematic review. Background. Lumbar segmental instability represents a low back pain subgroup. Several clinical tests have been proposed on this topic, but its clinical usefulness for detecting lumbar instability is not yet clear. Objectives. To summarize the current literature on the accuracy and reliability of the clinical tests for lumbar instability. Methods. Two independent reviewers searched Medline, Embase, Cinahl, PubMed and Scopus Databases. Diagnostic test studies were collected on Aberrant Movements Pattern (AMP), Active Straight Leg Raise test (ASLR), Passive Lumbar Extension test (PLE), Posterior Shear test (PST), Prone Instability test (PIT), and Prone and Supine Bridge tests (PB and SB). The quality of the studies was evaluated by QUADAS and QAREL scales. Results. Five articles respected search criteria about four tests. Two studies examined the diagnostic accuracy of AMP, PIT, PLE and PST, showing sensitivity from poor (AMP) to excellent (PLE) and specificity from moderate (PIT, PST) to excellent (AMP, PLE). The reliability of AMP, PIT, PLE and PST was investigated by four articles and resulted respectively low (PST), uncertain (AMP) and good (PLE, PIT). Conclusion. PLE test demonstrated excellent diagnostic accuracy and good reliability, PIT test good diagnostic accuracy and moderate reliability. AMP test showed high specificity, low sensitivity, and disputed reliability while PST showed lowest accuracy and reliability. These results suggest that PLE and PIT are the most appropriate tests to detect lumbar instability.