BackgRound: The use of anticonvulsants (e.g., gabapentin, pregabalin) to treat low back pain has increased substantially in recent years despite limited supporting evidence. We aimed to determine the efficacy and tolerability of anticonvulsants in the treatment of low back pain and lumbar radicular pain compared with placebo.

Study Design Clinical measurement study. Background The Lumbar Spine Instability Questionnaire (LSIQ) is a self-report measure of 15 items. Previous studies have used the LSIQ as a measure of clinical instability; however, a comprehensive evaluation of its clinimetric properties has not been conducted. Objectives The aim of this study was to evaluate the clinimetric properties of the LSIQ in patients with chronic non-specific low back pain (LBP). Methods We included patients with non-specific LBP presenting to primary care clinicians in Australia. Rasch analysis was conducted to assess item hierarchy, targeting, unidimensionality, person fit, internal consistency and differential item functioning. We also tested test-retest reliability for total scores and each item, and convergent and divergent validity. Results A total of 107 participants with LBP were recruited (60 men and 47 women). The results were variable. The LSIQ appeared to constitute a unidimensional measure, targeted the sample well and showed adequate test-retest reliability. However, the scale had poor internal consistency, did not appear to function as an interval-level measure and had unclear construct validity. Although no items appeared to be redundant, several items were biased by factors other than the proposed construct of the measure. Conclusions The LSIQ does not seem ready to be implemented in clinical practice. We suggest a theoretical reconsideration of this questionnaire. Although the LSIQ provided satisfactory estimates for some clinimetric features, we cannot consider it as an internal-level measure but rather an index. Future studies are needed to investigate whether the LSIQ measures clinical instability or some other construct. J Orthop Sports Phys Ther, Epub 22 Jun 2018. doi:10.2519/jospt.2018.7866.