Fig. 1From: Comparison of SDSG and CARDS classifications for L5/S1 lumbar degenerative spondylolisthesis: an independent inter- and intra-observer agreement studySpinal Deformity Study Group (SDSG) classification of lumbosacral spondylolisthesis. Low-grade spondylolisthesis: type 1 (low PI), type 2 (normal PI), and type 3 (high PI). High-grade spondylolisthesis: type 4 (balanced sacro-pelvis), type 5 (retroverted sacro-pelvis with balanced spine), and type 6 (retroverted sacro-pelvis with unbalanced spine)Back to article page