How To Treat Sacroiliac Disease And Piriformis Syndrome In Children?

My daughter was in a car accident 10 years ago. Had 3 pelvic fractures, one at the sacrum. She been diagnosed with Sacroiliac disease and periformis syndrome. She hasn t been able to find the correct kind of doctor to treat this or the pain she is constantly in. The daily pain has lead to depression. What kind of doctor treats these issues?