Fig. 1.

aTLIF inadequate fusion. CT scan at 16-month FU. Fused right facet joint (P1), interbody pseudarthosis (A-5). bTLIF solid fusion. CT scan at 22-month FU. Fused right facet joint (P-1), interbody solid fusion (A-1). cAPF inadequate fusion. CT scan at 33-month FU. L4–L5 posterior nonunion (P-3), interbody nonunion (A-5) L5–S1 posterior solid fusion (P-1), interbody nonunion (A-5). dAPF solid fusion. CT scan at 35-month FU. L4–L5 posterior solid fusion (P-1), interbody solid fusion (A-1). L5–S1 posterior solid fusion (P-1), interbody solid fusion (A-1)