Unnecessary Surgery

Why would anyone perform an unnecessary surgery?
I know of two reasons. One is to make money and the second is to gain power through other means such as contracts with equipment makers, publishing of articles on a subject, academic advancement or any other secondary gain.
Types of unnecessary surgery
One case deals with a patient who has been suffering from a symptom such as low back or neck pain where little is helping them with their problem. Diagnostic studies reveal little as to what is causing the pain and so surgery as a last resort is suggested. In today’s world of spine surgery, operations in these circumstances usually involve an instrumented fusion, but only in those circumstances where there is an adequate source of payment for the surgery. Some of these patients had the underlying condition present before they were involved in a minor accident and now they suddenly have a surgical condition.
Some of the unnecessary surgical procedures that I see are done by surgeons who have a hammer, as I call it, and they are looking for a nail to bang on. An example would be an ear, nose and throat (ENT) surgeon who performs endoscopic sinus surgery for conditions that could be managed without surgery, or a pain management physician doing questionable nerve blocks and nerve obliteration procedures without proper indications.
Every surgical procedure carries a risk of complications with it, and every surgical procedure should have well thought out indication to be done. I think that the recommendation for obtaining a second opinion is most important when surgery has been suggested.