The outcomes of intra-articular corticosteroid injection into sacroiliac joint following findings of single-photon emission computed tomography imaging: a retrospective case series.

Abstract

Dear Editor: The sacroiliac joint (SIJ) is the pain generator in 10%–30% of patients presenting with chronic low back pain.1 SIJ pain is usually felt in the buttock and can radiate to the lower back, groin, and posterior thigh.2 Treatment options include oral medication, physical therapy, and corticosteroid injections (CSI) into the SIJ.3 Corticosteroids have a strong anti-inflammatory effect, and patients with evident inflammation within or around the SIJ should have a better therapeutic outcome to CSI than those without. Anatomic imaging modalities, including radiography, computed tomography, and magnetic resonance imaging, can identify sites where degenerative changes and other anatomical abnormalities occur, but they have limitations in localizing the exact pain generators.4 In contrast, bone single-photon emission computed tomography (SPECT) allows the accurate localization of metabolically active sites.4 Bone tracers preferentially localize in areas of bone remodeling and increased perfusion, which could identify sites of inflammation and pain in the SIJ.5 Also, bone SPECT was shown to accurately determine the location of therapeutic injection for controlling low back pain.6,7 Accordingly, bone SPECT imaging could be useful in predicting the therapeutic outcome of intra-articular CSI in patients with SIJ pain by assessing the presence of inflammation within or around the SIJ.