Cycling low grade fevers after treatment for spinal infectinon?

My 19 year old daughter had spinal fusion surgery june 2009 for kyphosis. December 2009, she started having throbbing pain and fevers. March 2010, she underwent a clean out surgery, drs found a large pocket of pus in lower right part of her back. She was put on 6 week pic line then several months of oral antiobiotics. By may 2010, she started cycling fevers and pain again. In July 2010, drs removed all metals from her back and again found a large pocket of fluid in lower right area of back.She did 10 days of iv antiobiotics while in hospital. In Jan 2011, she started to have severe back pain again and fevers... March 2011, drs found her spine had fractured and then put metal rods back in to stabilize her spine. 24 hours after this surgery, her fever returned Drs could not locate infection. . She did 6 weeks of a picc line again and is currently on oral antiobiotics. Within the last 2 weeks, she has started to cycle low grade fevers, fatigue and back pain again. We have heard that residual infection can be left in her scar tissue and muscle around the spine and as she does more and moves more, this residual infection comes to the surface as fevers. Has anyone heard of this? We are desperate to get our daughter well.