This research design is called a “cohort comparison study,” and it is retrospective. Comparing minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) to minimally invasive unilateral laminotomy with bilateral decompression (MIS-ULBD) for the treatment of low-grade lumbar degenerative spondylolisthesis in terms of perioperative outcomes, radiographic parameters, and patient-reported outcome measures (PROMs) was the goal of this research.  Degenerative spondylolisthesis of the lumbar spine is quite prevalent, but the best way to treat it surgically is still up for debate. Newer minimally invasive surgical procedures (MIS) are thought to lower the risk of iatrogenic instability and may avoid the need for fusion since they maintain bone, paraspinal muscles, and posterior midline stabilizers. However, there are currently only a few trials comparing different MIS approaches for treating low-grade lumbar degenerative spondylolisthesis. Using a prospectively collected spine surgery registry from April 2017 through November 2021, researchers identified consecutive patients with low-grade (Meyerding grade I or II) lumbar degenerative spondylolisthesis treated with single-level MIS-ULBD or MIS-TLIF. Data from radiological imaging and patient-reported outcomes (PROMs) were also analyzed to evaluate perioperative success. MIS-ULBD or MIS-TLIF procedures were performed on 188 individuals (79 MIS-ULBD and 109 MIS-TLIF). Patients who underwent MIS-ULBD were found to be older, to have a higher Charlson Comorbidity Index, to have a lower mean percentage of back pain, to have a higher percentage of L4/L5 pathology, to have a shorter operative time, to have a lower estimated blood loss, and to have less postoperative pain (P<0.05). At 12 months, both groups showed statistically significant improvement on 5 of 6 PROMs (P<0.05): Oswestry Disability Index (ODI), visual analog scale (VAS)-back pain, VAS-leg pain, Short Form 12 Physical Component Score (SF12-PCS), and Patient-Reported Outcomes Measurement Information System (PROMIS). The minimal clinically meaningful difference at 1 year for any of the PROMs investigated was not associated with operation type on multivariate analysis adjusting for covariates. Patients with low-grade lumbar degenerative spondylolisthesis may benefit from either MIS-ULBD or MIS-TLIF, as both procedures were found to significantly reduce pain and increase physical function in the current study.