Radiographic and Patient-Reported Outcomes in Anteriorly Placed Transforaminal Lumbar Interbody Fusion Cage Versus Anterior Lumbar Interbody Fusion with Posterior Instrumentation

Study Design. Retrospective cohort study. Objective. To compare outcomes in anteriorly placed transforaminal lumbar interbody fusions (TLIFs) and anterior lumbar interbody fusions (ALIFs). Summary of Background Data. TLIF and ALIF are surgical techniques that have become more prevalent in recent years. Although studies have compared the two, none have considered TLIFs with anteriorly placed cages, which may serve as a better comparison to ALIFs. Patients and Methods. Patients undergoing TLIF or ALIF with posterior instrumentation from 2010 to 2020 at a tertiary care institution were retrospectively identified. TLIF cage position was assessed and those with anterior placement were included. Electronic medical records were reviewed to identify patient characteristics and patient-reported outcomes. Radiographic outcomes included posterior disc height (DH), lumbar lordosis (LL), sacral slope, pelvic incidence, and pelvic tilt. Statistical analysis was performed to compare the two groups. Results. Of the 351 patients, 108 had ALIF with posterior instrumentation and 207 had a TLIF. Preoperatively, patients undergoing TLIF had less LL (53.7° vs. 60.6°, P < 0.001), sacral slope (38.3° vs. 43.7°, P < 0.001), and pelvic incidence (60.1° vs. 66.1°, P < 0.001), all of which remained significant at 1-year and long-term follow-up (P < 0.001). The TLIF group had less ΔDH (1.51° vs. 5.43°, P < 0.001), ΔLL (1.8° vs. 2.97°, P = 0.038), and Δsegmental lordosis (0.18° vs. 4.40°, P < 0.001) at 1 year postoperatively. At 2 to 3 years, ΔDH (P < 0.001) and Δsegmental lordosis (P = 0.001) remained significant, but ΔLL (P = 0.695) did not. Patients in the TLIF group had higher Visual Analog Scale-Back scores 1 year postoperatively (3.68 vs. 2.16, P = 0.008) and experienced less improvement in Oswestry Disability Index (-17.1 vs. -28.6, P = 0.012) and Visual Analog Scale-Back (-2.67 vs. -4.50, P = 0.008) compared with patients undergoing ALIF. Conclusions. Our findings suggest that ALIF with posterior instrumentation performed superiorly in radiographic outcomes and patient-reported outcomes compared with anteriorly placed TLIFs. Anteriorly placed TLIF cages may not achieve the same results as those of ALIF cages.