OBJECTIVE The study aimed to investigate the frequency of anatomical variations on sacroiliac joint and reveal their importance by distinguishing the findings that mimic sacroiliitis in patients with low back pain.
STUDY DESIGN Descriptive study.
PLACE AND DURATION OF STUDY Ondokuz Mayıs University, Faculty of Medicine, Samsun, Turkey, from 2018 to 2020.
METHODOLOGY This study included all SIJ MRI examinations of patients ≥ 18 and<65 years of age during 24 months. Data collection consisted of the patient’s age at the time of imaging, gender, presence of active-chronic sacroiliitis and lumbosacral transitional vertebra. Also, all images were assessed for the presence of major sacroiliac joint variations described in the literature. Structural and edematous changes were noted.
RESULTS A total of 1020 MRI examinations were included. SIJ variations were identified in 323 of them. The frequency order of anatomical variants of SIJs was as follows: 1. LSTV (114 patients, 12.2%) 2. Accessory sacroiliac joint (80 patients, 7.8%); 3. Iliosacral complex (66 patients, 6.4%); 4. Sacral defect (61 patients, 5.9%) and 5. Isolated synostosis (2 patients, 0.2%). Structural and edematous findings were frequently observed in LSTV and accessory SIJ.
CONCLUSION We conclude that the lumbosacral transition segments and various anatomical SIJ variations are common in the low back pain population especially in women. Moreover, these variations may be associated with some degenerative and edematous signal intensity changes that mimic sacroiliitis.