Supradjacent disc-degeneration was the most common PJK mechanism. Fracture dislocation presented earliest and with greatest kyphosis. Reoperation was most frequent with screw pullout, lucency, and UIV+1 fracture, while neurologic deficits were most common with lucency and UIV+1 fracture. These results demonstrate that PJK/F occurs in many different forms and ideally should be analyzed independently to further improve our treatment of this vexing complication.
Chanbour et al. (Wed,) studied this question.