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 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.

1.    Dar G, Khamis S, Peleg S, Masharawi Y, Steinburg N, Peled N, Latimer B, Hershkovitz I. Sacroiliac joint fusion and the implications for manual therapy diagnosis and treatment. Manual Therapy. 2008;13:155-58.

In an effort to identify common symptoms or signs that may allow discrimination between inflammatory low back pain (ILBP) and mechanical low back pain (MLBP), Walker and Williamson recently surveyed experienced health professionals from five professions using a questionnaire listing 27 signs/symptoms. Of 129 surveyed, 105 responded (81%). According to their results, constant pain, pain that wakes, and stiffness after resting  were generally considered as moderate indicators of inflammatory LBP. Intermittent pain during the day, pain that develops later in the day, pain on standing for a while, pain bending forward a little, pain on trunk flexion or extension, pain doing a sit up, pain when driving long distances, pain getting out of a chair, and pain on repetitive bending, running, coughing or sneezing were all generally considered as moderate indicators of MLBP. There was, however, no consistency of agreement either between or within professional groups.

While the general absence of agreement regarding signs and symptoms of ILBP and MLBP does not invalidate the pathophysiological paradigms of mechanical and inflammatory pains, it does, however, signal the need for further research. This research should be aimed at testing the indicators identified in this study for their ability to predict the outcome of mechanical and anti-inflammatory treatments of LBP.

Walker BF, Williamson OD. Mechanical or inflammatory low back pain. What are the potential signs and symptoms? Man Ther. 2009 Jun;14(3):314-20. Epub 2008 Jun 13.

Physical activity is often suggested to be important in the prevention and management of low back pain. However, when viewed simply such advice does not take into account the possibility of U-shaped relation between the level of activity and back pain – i.e. both inactivity and excessive activities present an increased risk for back pain.

Heneweer et al. have analyzed cross-sectional data from the Dutch population-based Musculoskeletal Complaints and Consequences Cohort study (DMC(3), 1998) of a sex-age stratified sample of 25 years and older (n=3364). The type of activity (daily routine, leisure time and sport activity), intensity of and time spent on these activities, and back exertion of sport activities were all taken into account. Physical activity was not associated with chronic low back pain (CLBP) when studied by the dimension of activity, by the intensity or by the duration of physical activity. Only engaging in sport activity was associated with less CLBP. The extremes of the total physical activity pattern were associated with CLBP: a moderate increased risk for CLBP was found for both participants with a sedentary lifestyle and for those being involved in physical strenuous activities. This was especially true for women.

This study provides some evidence that the relationship between physical activity and CLBP is U-shaped. Total physical activity appeared to be more significant than individual dimensions of low back exertion.