Predicting Sacroiliac Syndrome: The Association Between Noninvasive Sacroiliac Joint Tests and Sacroiliac Joint Injections

Study Design. A prospective single sample observational design was performed. Sacroiliac tests that predicted ≥ 75% pain relief after sacroiliac joint (SIJ) injection were considered valid diagnostic tests for SIJ syndrome. Objectives. To identify valid noninvasive sacroiliac tests that can be used to diagnose SIJ syndrome. Summary of Background Data. The criterion standard for diagnosing SIJ syndrome is with SIJ intraarticular injections under fluoroscopy. This procedure is costly, invasive, and impractical for routine use. Clinicians need practical ways to diagnose SIJ syndrome; however, few studies have been performed to validate existing sacroiliac tests against SIJ Injections. Methods. Nineteen subjects who were scheduled for a SIJ injection, and without lumbar discogenic symptoms were recruited for the study. Subjects were included who identified their pain below the 5th lumbar vertebra (L5), including the posterior superior iliac spine (RSIS). Pain presentation could also include the groin, hip, and/or entire lower limb. Prior to the injection, four sacroiliac tests were performed: the march test, PSIS symmetry, sacroiliac ligament tenderness, and the supine to long-sit test. Subjective pain intensity was recorded before and after the injection, on a 0 to 10 scale. Results. The supine to long-sit test was a valid and fair predictor of sacroiliac joint syndrome (sensitivity = 100%, specificity 45%, PV+ = 50%, PV- = 100%, p=.026). Conclusion. The supine to long-sit test is a fair predictor of sacroiliac joint syndrome when used in combination with sacroiliac tests that are highly specific for SIJ syndrome. Keywords: Sacroiliac joint, injection, diagnosis, validit