I am not an expert but that just dont sound right.I thought all hardware was permanent.If it were me I would consult another surgeon before I went through this again.
All of the "instrumentation" looks fine - nothing loose. Another problem is I'am very lean in build - not much meat on my bones for fusion to take place.
I'm guessing there are screws and cables to remove which can be irritating some nerves. Have you asked about that?