Sacroiliac joint pain: a comprehensive review of epidemiology, diagnosis and treatment

Sacroiliac joint (SU) pain is an underappreciated source of mechanical low back pain, affecting between 15 and 30% of individuals with chronic, nonradicular pain. Predisposing factors for SIJ pain include true and apparent leg length discrepancy, older age, inflammatory arthritis, previous spine surgery, pregnancy and trauma. Compared with facet-mediated and discogenic low back pain, individuals with SIJ pain are more likely to report a specific inciting event, and experience unilateral pain below L5. Owing in part to its size and heterogeneity, the pain referral patterns of the SIJ are extremely variable. Although no single physical examination or historical feature can reliably identify a painful SIJ, studies suggest that a battery of three or more provocation tests can predict response to diagnostic blocks. Evidence supports both intra- and extra-articular causes for SIJ pain, with clinical studies demonstrating intermediate-term benefit for both intra- and extra-articular steroid injections. In those who fail to experience sustained relief from SIJ injections, radiofrequency denervation may provide significant relief lasting up to 1 year. This review covers all aspects of SIJ pain, with the treatment section being primarily focused on procedural interventions.