PET/CT after PLIF spondylodesis. Example of a patient, 7 months after PLIF for a lysis-olisthesis of L5-S1. Moderate subsidence on CT (upper left, closed arrow) and vertebral endplate activity on PET (upper right). Associated pedicle screw entrance point hyperactivity on PET (lower right, cross), possibly indicating continued bone stress post-surgery. The intervertebral area (dotted arrow) shows the bone fragments inside the cage and one of its posterior radiological markers.