The objective of this study was to evaluate the pain relief effect of locally injected corticosteroid treatment in women with long-lasting sacral low back pain with onset during pregnancy. Thirty-six women were allocated to injection treatment, with slow-release triamcinolone and lidocaine or saline and lidocaine, given at the sacrospinous ligament insertion on the ischiadic spine bilaterally with 4 weeks follow-up time. Primary outcome measure was reported pain intensity on visual analogue scale and secondary outcome measures number of pain-drawing locations and pain-provoking test results. The triamcinolone treatment group had significantly reduced pain intensity, number of pain locations, and pain-provoking test results between baseline and follow-up as compared with the saline treatment group. A reduced number of pain drawing locations was reported by 16 of 18 women in the triamcinolone group as compared with 10 of 18 in the saline group. In the triamcinolone treatment group, 17 of 18 women had an improved pain provocation test result as compared with 9 of 18 in the saline treatment group.
The anatomic region around the sacrospinous ligament insertion on the ischial spine is suggested to be one source of long-lasting sacral low back pain with onset during pregnancy. The pain was relieved by slow-release corticosteroid injection treatment to the ischial spine.