Table 3. Spine surgeons’ familiarity with vertical spinal instability concept.

1. How familiar are you with the concept of “vertical instability” being the result of degenerative disc disease and collapse of the lumbar motion segment causing sciatica-type back- and leg pain on a Likert scale from 1 to 10?

2. On a Likert scale from 1 to 10, how likely are you to agree with the statement that vertical instability is the result of a collapsing lumbar disc? 1–10

3. On a Likert scale from 1 to 10, how likely are you to agree vertical instability precedes anterolateral lumbar instability (degenerative spondylolisthesis)?