One hundred twelve patients with lumbar degenerative disease (LDD) were randomized to TLIF (transforaminal lumbar interbody fusion)+unilateral pedicle screw fixation (UPSF) (n=54) or TLIF+bilateral pedicle screw fixation (BPSF)(n=58). The primary outcome of interest was health-related quality of life (SF-36 PCS/MCS); secondary outcomes included operative time, blood loss, time to ambulation, length of stay, perioperative complications, pain (VAS), disability (ODI), neurological function (JOA), fusion (Bridwell), and global rating (modified MacNab). Outcomes were assessed at 1, 6, and 12 months after surgery. Overall, the results of the study revealed that UPSF shortened operative time and reduced blood loss, lowered complication rates, and yielded higher SF-36 scores at 6 and 12 months, while VAS/ODI/JOA, fusion, and MacNab outcomes were similar between groups. These findings suggest TLIF+UPSF is a less invasive alternative that preserves efficacy and enhances longer-term quality of life in the elderly.