Should a Lumbar MRI for back pain routinely include the sacro-iliac joint?

Back pain is a common problem and has been shown to affect approximately 85% of the adult population at any one time. The source of this pain can be difficult to identify and the sacroiliac joint (SIJ) has been proposed as a possible pain source. Its percentage contribution to lower back pain is controversial. Clinical provocative tests for SIJ pathology have been developed but these have high intra and inter-observer variability and the significant of positive findings is unclear. This study proposes that the SIJ should not be imaged as part of a routine MRI lumbar spine series.