Utilization of L5-S1 interbody cage in adult spinal deformity patients undergoing lumbar spinal osteotomies and spinopelvic fixation: A retrospective comparative study

Adult spinal deformity (ASD) surgeries often face complications, such as pseudoarthrosis and rod fractures (RFs), particularly at the lumbosacral junction. While transforaminal lumbosacral interbody fusion (TLIF) at L5-S1 is thought to improve outcomes, its efficacy in major ASD surgeries remains unclear. This study aims to compare clinical and radiological outcomes and implant complications in patients undergoing spinopelvic fixation with or without L5-S1 TLIF.

A retrospective cohort study was conducted, including 157 ASD patients who underwent high-grade osteotomies and spinopelvic fixation from 2021 to 2024. Patients were divided into two groups: those with L5-S1 TLIF (C group, n = 71) and those without (NC group, n = 86). Outcomes included rod fracture (RF) rate, sagittal alignment, and patient-reported measures such as the Visual Analog Scale (VAS), Oswestry disability index (ODI), and 36-Item Short Form Survey (SF-36), assessed at baseline, 1, 6, and 12 months postoperatively.

RFs were significantly lower in the C group (4% vs. 13%, P = 0.03). Improved postoperative sagittal vertical axis and pelvic tilt were noted in the C group (P < 0.01). Both VAS and ODI scores were significantly better at 6 and 12 months in the C group (P < 0.01), along with higher SF-36 scores. No significant differences in baseline characteristics, estimated blood loss, or operation time were observed.

The use of L5-S1 TLIF reduces RF rates, improves sagittal alignment, and clinical outcomes in ASD surgery. Incorporating TLIF at L5-S1 may optimize outcomes without increasing perioperative risks.