Sponylolisthesis eMedicine Radiology

Description: The word spondylolisthesis is derived from the Greek words spondylo, meaning spine, and listhesis, meaning to slip or slide. Spondylolisthesis is a descriptive term referring to slippage (usually forward) of a vertebra and the spine above it relative to the vertebra below.
Diagram shows how to grade spondylolisthesis. The 2 arrows, one indicating vertebral body width and the other indicating the amount of slippage that has occurred, represent the measurements needed. The ratio of amount of slippage to vertebral-body width is obtained as a percentage. Grade 1 is a ratio of 0-25%, grade 2 is 25-50%, grade 3 is 50-75%, and grade 4 is 75-100%.
Zubin Irani, MD, MBBS & Jehangir J Patel, MD Updated: Sep 14, 2009