Is sacroiliac joint fusion surgery a major surgery?

Yes: Sacroiliac fusion is rarely done for a very specific type of back pain coming from the sacroiliac joints. A very thorough work up is needed prior to surgery to be sure that the symptoms are coming from sacroiliac joint problems. If not and the surgery is done, the person will be no better afterwards and my in fact be worse.

Safe but yes: The si joint fusion is only indicated for patients that have failed extensive conservative care and have been symptomatic for at least 6 months. It is a viable option but most patients will get better with appropriate therapy.