Figure 1From: The effects of anterior vacuum disc on surgical outcomes of degenerative versus spondylolytic spondylolisthesis: at a minimum two-year follow-up Radiography of degenerative and spondylolytic spondylolisthesis. (A) Radiograph, showing a case of degenerative spondylolisthesis (L4-5) with an anterior disc vacuum sign. (B) Radiograph, showing a case of isthmic spondylolisthesis (L5-S1) with an anterior vacuum phenomenon.Back to article page