Cranial osteopathic manipulation can be quite effective in treating tinnitus.
By manipulating cranial bones and varying the tensions on the dural membranes and tension on the auditory nerve
(cranial nerve 8), much can be done to help with tinnitus. I (medical student dave miller) have certainly benefited from this treatment. It is a specialized skill so you might have to hunt to find a doc.
Answer assisted by David Miller, Medical Student