This seems to be a confusing subject with some conflicting information.
I have never been to an osteopath, but I have always considered them equivalent to regular M.D.'s and Wikipedia seems to agree somewhat:
http://en.wikipedia.org/wiki/Cranial_osteopathyThe scope of practice of osteopathic practitioners varies by country. The American Osteopathic Association recommends using the terms osteopathic physician and osteopathic medicine to distinguish individuals trained in osteopathic medicine in the United States who have attained the degree of Doctor of Osteopathic Medicine (D.O.), a degree equivalent, though different in certain aspects, to that of Doctor of Medicine (M.D.),[2][3][4][5] who practice the full scope of medicine and receive additional training in osteopathic manipulative medicine from individuals described as osteopaths who use osteopathy, the restricted-scope form of practice outside of North America.
But then they go on to say this:
The use of osteopathy is not always based on science, and there is little evidence that osteopathy is effective in treating any medical condition except for lower back pain.
Doctors Hospital is located in the town where I live and it seems to operate as any other hospital would:
https://www.ohiohealth.com/aboutdoctors/ As to craniosacral therapy, this is what Wikipedia says:
Craniosacral therapy (CST), or cranial-sacral therapy, is an alternative therapy used by occupational therapists, physiotherapists, massage therapists, naturopaths, and chiropractors. Craniosacral therapy was developed by Dr. John Upledger around 1983, and is loosely based on osteopathy in the cranial field (OCF), which was developed in 1899 by William Garner Sutherland. In the United States, OCF, or cranial osteopathy, as it is more commonly known, can only be practiced by fully licensed physicians (DOs, MDs and, in some states licensed naturopathic physicians, or NDs) and dentists. Cranial osteopathy is considered an extension of osteopathic medicine, and its training is therefore strictly regulated by the osteopathic medical profession and its governing bodies.[1]
The settled scientific consensus is that craniosacral therapy is pseudoscience,[2] and its practice quackery.[3] Medical research has concluded that there is no evidence for the therapy's effectiveness.[4] However, research remains ongoing[citation needed] to determine if mobility of the cranial bones exists and to determine if OCF can be shown to have any therapeutic applications.
So it seems to me that if you have had craniosacral therapy done to you and it works, great for you. If you are considering getting it done, make sure the person has been trained to do it (i.e., with a lot of letters after their name), but don't expect miracles.
As to anyone claiming this has been influenced by Native Medicine bonesetters and is part of their shamanic healing, I would run the other way.