Possible role of the long dorsal sacroiliac ligament in women with peripartum pelvic pain.

BACKGROUND To enhance the understanding of the pathophysiology of women with peripartum pelvic pain, it is necessary to couple anatomical insights with relevant clinical research. In this context, the long dorsal sacroiliac ligament is especially of interest because it was noticed that women diagnosed with peripartum pelvic pain frequently experience pain within the boundaries of this ligament. Njoo (1) found a high intertester reliability and a high specificity for long dorsal sacroiliac ligament pain. The present article focuses on the possible role of the long dorsal sacroiliac ligament in the pain pattern of women with peripartum pelvic pain. The diagnostic and therapeutic consequences are considered. STUDY DESIGN A cross-sectional analysis was performed in a homogenous group of women meeting strict criteria for posterior pelvic pain since pregnancy, diagnosed as having peripartum pelvic pain and excluded for any history of fracture, neoplasm or previous surgery of the lumbar spine, the pelvic girdle, the hip joint or the femur. The patients were also excluded for signs indicating radiculopathy: asymmetric Achilles tendon reflex and/or (passive) straight leg raising restricted by pain in the lower leg. METHODS The study group comprised 178 women diagnosed with peripartum pelvic pain, selected from the outpatient clinic of a specialized rehabilitation center. Selection was based on criteria enabling a strict division between lumbar and pelvic complaints. Pain in the long dorsal sacroiliac ligament was detected by standardized palpation of the long dorsal sacroiliac ligament by specifically trained physicians and scored on a modified scale. Comparisons with the posterior pelvic pain provocation test and the active straight leg raise test was carried out. RESULTS The present study confirms that the long dorsal sacroiliac ligament frequently shows tenderness on palpation in patients with peripartum pelvic pain. Sensitivity was 76%. Sensitivity in a group of 133 women of the study group that scored positive on both active straight leg raise and posterior pelvic pain provocation tests was 86%. When only severe pelvic patients were included, sensitivity increased to 98%. In comparisons between the posterior pelvic pain provocation and the long dorsal sacroiliac ligament tests on the left and right side, Pearson's correlation coefficient was 0.33 and 0.41, respectively. In comparisons between the active straight leg raise and the long dorsal sacroiliac ligament tests on the left and right side, Pearson's correlation coefficient was 0.35 and 0.41, respectively. CONCLUSIONS The present study, carried out on a group of peripartum pelvic pain patients with strict in- and exclusion criteria, attempts to further elucidate the pathophysiology of patients with peripartum pelvic pain by adding a simple pain provocation test. It is concluded that the combination of the active straight leg raise, the posterior pelvic pain provocation and the long dorsal sacroiliac ligament pain tests combined with the proposed in- and exclusion criteria seems promising in differentiating between mainly lumbar and pelvic complaints. Although the sensitivity of the long dorsal sacroiliac ligament pain test seems promising, further clinical study is necessary in targeting specifically the long dorsal sacroiliac ligament. It is suggested that studies initiated to show the prevalence of sacroiliac joint pain in patients presenting nonspecific lumbopelvic pain, by using intra-articularly double block injection techniques, should include a peripheral injection of at least the long dorsal sacroiliac ligament.