Assessment and treatment for sacroiliac dysfunction is common in manual therapy management for spinal pain and is based on the assumption that small movements occur at the sacroiliac joints (SIJ). SIJ dysfunction is often addressed using manipulation techniques, usually involving the application of manual forces to the joint complex. Considering the fact many of these treatments rely on the hypothesis that SIJ motion is directly alterable by such forces it is important for practitioners to be aware that producing movement at the SIJ may not be possible in many individuals due to the presence of joint fusion.
Dar et al.1 have recently conducted a study with aim of determining the prevalence of SIJ fusion using 3-D CT imaging. The study examined 287 consecutive patients (159 male, 128 female) referred to a hospital radiology department for a variety of abdominal complaints. The patients ranged from 22-93 years. Patients with spinal diseases, such as spondyloarthropathy and diffuse idiopathic hyperostosis (DISH), were excluded. Unfortunately, information on low back pain status was not reported. 3-D images of pelvises were obtained using a 64-slice CT scanner, and volume rendering sections of 1-2mm thickness. Multiplanar reformation was used to detect whether the fusion was intra- or extra-articular. The SIJs of each image were divided into six equal areas and the presence, side and location of fusions were recorded. Assessment was made by two radiologists who were blind to each others results and the interexaminer agreement was substantial.
SIJ fusion was found in 16.7% of subjects and was far more prevalent in males (27.7%) than females (2.3%). All fusions were extra-articular. Fusion in males was strongly correlated with age: 5.6% in the 20-39y.a. cohort, 15.85% in the 40-59y.a. cohort, 31.1% in the 60-79y.a. cohort, 46.7% in individuals aged over 80. Fusion among females was not significantly correlated with age. Fusion was present bilaterally in 11.9% of males. Diffuse fusion was present in 7.5% of males, four cases were bilateral. The superior region was involved in all male individuals manifesting the phenomenon. No fusions were isolated to the inferior part of the joint. Fusion of the females was at just above and under the arcuate line at the most anterior point of the joint.
The results of this study accord with previous skeletal and cadaver studies and demonstrate that SIJ fusion is common. Further, it is clearly an age and gender biased phenomenon. The authors suggest that osteopaths and other manual therapists who frequently utilise manipulation techniques aimed at addressing sacroiliac articular mobility or that result in forces across the sacroiliac joint should be aware of the limited potential for compliance at this joint in older males. The risk of injury may be far greater than the potential benefits of manually applied forces during the treatment of SIJ dysfunction in this population.
