Had my 10 month appt. today, for a l4l5 / l5s1 tlif.
Had a CTscan last week, and my NS looked at it today, told me i'm fully fused at l4l5, but l5s1 is just now starting to show signs of fusing.
Why they dont fuse at the same rate, i have no idea, and i forgot to ask NS, but i go see him again in 2 months, and will ask then.
Also getting another CTscan in 6 months to check progress,and hoping it shows i'm fully fused at that time.
Wait and see.