Identification of the correct lumbar level using passive intersegmental motion testing

This study aimed to assess the accuracy and agreement between examiners when attempting to identify a single lumbar spinal level using passive intersegmental motion testing, a technique commonly used by physical therapists. Thirty-five adults were examined independently by an experienced and a novice clinician. Each examiner was asked to identify and note the interspace between the fifth lumbar vertebra and the first sacral vertebra, and to mark it. The mark was invisible to the second clinician asked to identify the same lumbar interspace. The true level was then identified by fluoroscopic imaging and was correct in 54-57% of cases. Interobserver agreement was poor. A significant learning effect was found for the experienced examiner, with proportionately more correct levels identified during the second part of the study (79%) when compared to the first (31%). The results show that intersegmental motion testing is a relatively unreliable method of identifying the correct spinal level.