Clinical tests to diagnose lumbar segmental instability : a systematic review

Study Design: Systematic literature review. Objectives: To evaluate the diagnostic accuracy of clinical tests used to diagnose patients with structural lumbar segmental instability (LSI). Backround: Patients with structural LSI represent an important, identifiable subgrouping of individuals with low back pain. Numerous clinical tests have been proposed to diagnose structural LSI; however, data on the diagnostic accuracy of these tests have not yet been evaluated through a systematic review of the literature. Methods: A systematic review was conducted in 6 electronic databases for diagnostic accuracy studies, published between January 1950 and March 2010, that evaluated clinical tests against radiological diagnosis of structural LSI. The diagnostic accuracy of the clinical tests from the retrieved articles was independently evaluated, reviewed, and quality scored using the QUADAS tool. Results: Four articles and a total of 11 clinical tests used in the diagnosis of structural LSI met the study inclusion criteria. The majority of tests had high specificity but low sensitivity, with positive likelihood ratios ranging from very small to moderate. QUADAS scores ranged from 16 to 25 out of a possible 26. The passive lumbar extension test was the most accurate clinical test, with high sensitivity (84%), specificity (90%), and a positive likelihood ratio of 8.8 (95% CI: 4.5, 17.3), indicating that this clinical test may be useful in the differential diagnosis of structural LSI. Conclusion: This systematic review found that the majority of clinical tests routinely employed to diagnose structural LSI demonstrated only limited ability to do so. The results do, however, indicate that the passive lumbar extension test may be useful in orthopaedic clinical practice to diagnose structural LSI. Additional research is required to further validate its use for diagnosing structural LSI in all populations of those with low back pain.