Methods: Between 2011 and 2018, data from 447 consecutive patients undergoing one/two-level lumbar fusion were analyzed. Posterior lumbar interbody fusion (PLIF) with bilateral muscle strip or Wiltse approach, open transforaminal lumbar interbody fusion (TLIF) and minimally invasive TLIF, and posterolateral fusion only were among the surgical techniques used. Core outcomes measure index (COMI) questionnaires were distributed before surgery and at 3 months, 1 year, and 2 years postoperatively to establish patient selfreported outcome measures. Demographic data (age, gender, and body mass index [BMI]) for each patient were also collected in addition to surgical indication, previous operative history, perioperative outcomes, and complications, and whether later revision surgery was required. Pearson’s chi-square test, Kruskal-Wallis test, repeated measure mixed-effects models, and ordinal logistic regression were used for statistical analysis. Results: Postoperative COMI scores improved across all procedures compared with pre-surgery (p<0.001). There was no significant difference between different postoperative COMI scores. Significant predictors of higher postoperative COMI score included higher pretreatment COMI score (p≤0.001), previous surgery (p≤0.04), younger age (p≤0.05), higher BMI (p≤0.005), and the indications of lytic spondylolisthesis (p=0.02) and degenerative disc disease (p<0.001). Patients undergoing minimally invasive TLIF had a significantly shorter post-surgery stay than patients undergoing open PLIF (Kruskal-Wallis test, p=0.03). Conclusions At 2 years postoperatively, there was no significant difference in clinical outcomes between open and minimally invasive techniques. These findings suggest that the main determinant of surgical approach should be surgeon preference and training.