For a study, the researchers sought to determine any risk variables for radiographic ASD in individuals who had single-level PLIF for L5–S1 spondylolysis spondylolisthesis. The researchers conducted retrospective research. The research looked at 135 patients with symptomatic L5–S1 spondylolysis spondylolisthesis with single-level PLIF. There were 91 men and 44 women in total. Standing radiographs were used to quantify the preoperative and postoperative spinopelvic parameters, % slip, sacral slope, lumbar lordosis (LL), pelvic tilt, pelvic incidence (PI), PI minus LL (PI−LL), lumbosacral angle, C7 sagittal vertical axis, and thoracic kyphosis. Between the pre-and postoperative radiographs, radiographic ASD was defined as disc height loss (>3 mm), an increase of posterior angulation (>5°), or advancement of spondylolisthesis (>3 mm). The classification of Pfirrmann was employed to assess disc degeneration. For the non-ASD and ASD groups, radiographic parameters and variations between pre-and postoperative values were assessed and compared. The adjusted correlations between each putative explanatory variable and ASD development were evaluated using binary logistic regression analysis. The incidence of ASD was found to be 11% on radiography. Furthermore, at 1 year, 60% of individuals with ASD developed radiographical ASD, and all occurrences of radiographical ASD during this follow-up period happened within 3 years of the first operation. The average time for ASD to appear after initial surgery was between 21.7 and 12.6 months. For radiographic ASD, no patients required reoperation. A preoperative (OR, 5.9; 95% confidence interval [CI], 1.2–28.9; P=0.03) and postoperative (OR, 6.5; 95% confidence interval [CI], 1.2–34.5; P=0.03) PI LL of more than or equal to 15° were both risk factors for radiographical ASD, according to multivariate analysis. In patients with L5–S1 spondylolysis spondylolisthesis, PI−LL value mismatch was a significant independent risk factor for radiographic ASD before and after surgery. Getting a bigger lordosis at L5–S1 could have been the key to avoiding radiological ASD.