Laxity measurements of the Sacroiliac joints in women with pregnancy-related pelvic pain

The review of the origin, the diagnosis and treatment of pregnancy-related pelvic pain led to the conclusion that laxity of the S!Js may play a central role in the understanding of this syndrome. The department of Biomedical Physics and Technology and the department of Rehabilitation have studied the biomechanical properties of the pelvic joints, in particular the SUs for many years. Because no instrumented method was available, Snijders proposed a new vihration method for the in vivo assessment of SIJ laxity. This resulted in the method of Doppler imaginj\ of vibrations (DIV), which runs as a continuous thread throughout this thesis. 3·14 Chapter 2 describes the intra- and inter-tester reliability indexes of D!V in SIJ laxity measurements performed by several testers, including one experienced tester as well as inexperienced testers. The contribution of various sources of measurement enor associated with the measurement design is also addressed. Chapter 3 presents the pregnancy part of a longitudinal study on 163 subjects with and without PRPP. This study was designed to investigate the association between PRPP and S!J laxity at 36 weeks of pregnancy. Chapter 4 describes the postpartum part of the study presented in chapter 3. The aims of this study were to describe the association between PRPP and SIJ laxity 8 weeks after childbirth and to determine to what extent asymmetric laxity of the SUs during pregnancy has predictive power with regard to postpartum PRPP. Chapter 5 presents a study designed to establish the influence of a pelvic belt on S!J laxity. The belt was tested at two positions (low: at the level of the pubic symphysis, and high: just below the anterior superior iliac spines) and at two tensions (50 and 100 N) in ten healthy subjects. Finally, the study in chapter 6 investigates the influence of a pelvic belt at low and high position on SIJ laxity and its effect on the active straight leg raise (ASLR) test in 25 women with PRPP.