[ceejayoz]

That's a pretty reasonable filter to have. Sure, there'll be some cases like yours where you've got enough knowledge to request a specific surgery, but for every one of those there's likely to be several "your back pain is caused by weight and posture, surgery isn't indicated" (and the occasional "why don't we see a psychiatrist about that radio the CIA put in your brain instead of a neurosurgeon...") that the GP can winnow out at a quarter of the cost and without tying up an already in-demand specialist.