For adult symptomatic thoracolumbar/lumbar scoliosis, few studies have examined fractional curve correction following lengthy fusion between transforaminal lumbar interbody fusion (TLIF) and anterior lumbar interbody fusion (ALIF). This study aimed to assess a fractional penalty, HRQL, and complications associated with L4–S1 TLIF with ALIF as a surgical therapy for ASLS. The authors used a prospective multicenter adult spinal deformity database to conduct a retrospective analysis. A fractional curve of less than 10°, a thoracolumbar/lumbar curve of less than 30°, index TLIF or ALIF performed at L4–5 and L5–S1, and a minimum 2-year follow-up were all required for inclusion. The number and kind of interbody fusions at L4–S1 were propensity-matched between TLIF and ALIF patients.

The required 2-year follow-up was obtained by 106 (78.5%) of 135 theoretically eligible consecutive patients mean ± SD age 60.6 ± 9.3 years, 85% women, 44.3% underwent TLIF, and 55.7% underwent ALIF). ALIF patients had higher cage height (10.9 ± 2.1 mm for TLIF patients vs 14.5 ± 3.0 mm for ALIF patients, p = 0.001), lordosis (6.3° ± 1.6° for TLIF patients vs 17.0° ± 9.9° for ALIF patients, p = 0.001), and surgical length (6.7 ± 1.5 hours for TLIF patients vs 8.9 ± 2.5 hours for ALIF patients, p < 0.001). Total complications were similar (76.6% for TLIF patients vs 71.2% for ALIF patients, p = 0.530), while TLIF patients had significantly more rod fractures (28.6% of TLIF patients vs 7.1% of ALIF patients, p = 0.036). A 1-mm increase in L4–5 TLIF cage height resulted in a 2.2° reduction in L4 coronal tilt (p = 0.011), while a 1° rise in L5–S1 ALIF cage lordosis resulted in a 0.4° increase in L5–S1 segmental lordosis (p = 0.045).

Despite using substantially bigger, more lordotic ALIF cages, surgical treatment of ASLS with L4–S1 TLIF versus ALIF resulted in equal mean fractional curve correction (66.7% vs 64.8%). The ALIF cage lordosis substantially impacted restoring lumbosacral lordosis, whereas the TLIF cage height considerably affected leveling L4 coronal tilt. The benefits of TLIF may include shorter operation times and shorter hospital stays; nevertheless, the related HRQL was lower, and more rod fractures were seen in the TLIF patients in this investigation.