Figure 6.

(A–F) Preoperative anterioposterior X-ray, CT, and MRI show L5 spondylolisthesis, with compression of spinal cord. (G, H) Postoperatively, PLIF was performed at L5-S1. (I) Three months later, the lateral X-ray showed cage migration posteriorly of 5 mm. (J) Six months later, the lateral X-ray showed cage migration posteriorly, without significant change when compared with postoperative condition. (K) Twelve months later, the lateral X-ray showed cage migration posteriorly, without significant change when compared with postoperative condition.