For a study, the researchers sought to determine a link between vertebral HU value and cage subsidence after OLIF. Researchers conducted retrospective research. Cage subsidence, disc height, global HU value of the vertebral body, HU value of the upper and lower instrumented vertebrae, HU value of the endplate, fusion rate. Patients who had single-level OLIF at one institution between October 2017 and August 2020 were included in the retrospective research. Cage subsidence was assessed post-operatively using a CT scan based on cage protrusion through the vertebral endplates. Preoperative CT was used to calculate the HU values, which were calculated using previously published procedures. The research comprised 70 individuals who were followed for an average of 15.4 months. The subsidence rate (n=18/70) was 25.7%. With a 0–7.7 mm range, the average cage subsidence was 2.2 mm. Age, sex, and body mass index (BMI) did not differ significantly between the 2 groups. The lumbar vertebral body (L1–5) had a mean global HU value between 142.7 and 30.1 in nonsubsidence and somewhere between 103.7 and 11.5 in subsidence (P=0.004). The HU value of the upper instrumented vertebrae (UIV) was somewhere between 141.4 and 29.7 in nonsubsidence and somewhere between 101.1 and 10.2 in subsidence, respectively (P=0.005). In nonsubsidence, the lower instrumented vertebrae (LIV) HU value was somewhere between 147.4 and 34.9, while in subsidence, it was somewhere between 108.1 and 13.7 (P<0.001). The UIV HU value’s AUC was 0.917 (95% CI: 0.853–0.981), and the HU value’s most acceptable threshold was 115. (sensitivity: 84.6% , specificity: 100%). The LIV HU value’s AUC was 0.893 (95% CI: 0.819–0.966), and the HU value’s most acceptable threshold was 125. (sensitivity: 76.9% , specificity: 100%). The mean HU value for the top endplate was somewhere between 235.4 and 50.9, while the mean HU value for the lower endplate was between 193.4 and 40.3. There was no significant difference between the 2 groups (upper endplate P=0.314, lower endplate P=0.189). Cage subsidence after single-level OLIF was linked to lower pretreatment vertebral body HU values. On the other hand, the endplate HU values were not linked to cage sinking. The cage sinking could have been predicted using preoperative HU measurements.