Ray:
Please accept my sympathy for your wife's suffering, apparently brought about by a metal clip that may have been 'left behind' during her AN surgery in 1999. I assumed that surgical instruments and/or temporary items (such as a surgical clip) used during surgery were carefully accounted for before the incision was closed. Perhaps my assumption was a tad naive. I'm surprised the follow-up MRI scans didn't show the metal artifact but if you didn't see them and, as you claim, the doctor gave you inaccurate information, I can understand how that might happen. This is clearly a case for an attorney specializing in medical malpractice to look into. I did not have any issues following my surgery so I cannot offer any personal knowledge that might help you.
I concur with Brian ('Pooter') that it would seem advantageous for your wife's health to consider having the offending artifact surgically removed to help alleviate her distress. As for the metallic dust issue, my neurosurgeon was aware of it, as well as bone dust, and he employed his assistant (another neurosurgeon he is mentoring) to deal with it, although I'm not certain exactly what method they used because I never asked for my surgery report as I saw no need to do so. I believe most surgeons performing skull surgery these days use some kind of sticky gauze to absorb the dust around the drill site and also employ suction to keep the operating area clean. Because your wife underwent her AN surgery a decade ago, this may not have been the standard procedure, then. I have no idea. This is why you need to consult an attorney with experience in this aspect of medical malpractice thresholds. I wish you well as you pursue a remedy for this unhappy situation.
Jim