Fig. 1. Progressive degeneration of proximal adjacent segment (arrow indicates the level of adjacent segment pathology) was observed after lumbar spinal fusion from L3 to S1 in 57-year-old gentleman. Progressive settling, development of retrolisthesis, and segmental kyphosis was gradually developed in the adjacent segment during follow-up. The patient was treated by minimally invasive direct lateral interbody fusion of the adjacent segment and posterior extension of fusion. Postoperative (A) 3 months, (B) 6 months, (C) 9 months, (D) 12 months, (E) 18 months, and (F) after revision.