I had spinal fusion at L4-L5. My own bone was used in the cages. I understand new bone growth is very important. I was told bending too soon will disrupt, slow, or stop new bone growth. Is this true? I'm 7 weeks post-op. My six week dr appt went well. I was told the new X-ray looks good and on target. At what stage, week, will new bone growth be seen?