Trans-sacral screw fixation in the treatment of high dyplastic developmental spondylolisthesis

Figure 1 Seriated radiological exams showing the progression of the spondylolisthesis from grade I in 1963, to grade III in 2010.

Figure 2 Analysis of the severity index and of the square of unstable zone. It’s described by Lamartina[14]. SI: Severity index.

Figure 3 Intraoperative picture that showed the insertion of the trans sacral screw.

Figure 4 Computer tomography scan at 12 mo follow-up that showed the correct positioning and fusion of the system.