Comparative Effectiveness of Adjustable Lordotic Expandable versus Static Lateral Lumbar Interbody Fusion Devices: One Year Clinical and Radiographic Outcomes

Abstract

Aims: This study aims to understand the clinical and radiographic outcomes between patients treated with static and expandable interbody spacers with adjustable lordosis for minimally invasive (MIS) lateral lumbar interbody fusion (LLIF). Background: The use of large interbody spacers in MIS LLIF offers favorable clinical and radiographic results. Static interbody spacers may cause iatrogenic endplate damage and implant subsidence due to forceful impaction and excessive trialing. Expandable interbody spacers with adjustable lordosis offer in situ expansion that may optimize endplate contact and maximize and maintain sagittal alignment correction until fusion occurs. Objective: The objective of this study is to compare the clinical and radiographic outcomes between patients treated with static and expandable interbody spacers with adjustable lordosis for MIS LLIF. Methods: This is a multi-surgeon, retrospective, Institutional Review Board-exempt chart review of consecutive patients who underwent MIS LLIF at 1-2 contiguous level(s) using either a polyetheretherketone (PEEK) static (32 patients) or a titanium expandable spacer with adjustable lordosis (57 patients). The mean differences of radiographic and clinical functional outcomes were collected and compared from preoperative up to 12-month postoperative follow-up. Statistical results were significant if P<0.05. Results: The mean improvement of VAS back pain scores from preoperative to 6 and 12 months was significantly higher in the expandable group compared to the static group (P<0.05). Mean improvement of Oswestry Disability Index (ODI) scores from preoperative to 3, 6, and 12 months were significantly higher in the expandable group compared to the static group (P<0.001). The expandable group had a significantly greater mean improvement in segmental lordosis from preoperative to 6 weeks, 3, 6, and 12 months (P<0.001). For disc height, the mean improvement from preoperative to 6 weeks and 3 months was more significant in the expandable group compared to the static group (P<0.05). In the expandable group, the mean improvement from preoperative to 6 weeks, 3, and 6 months was significantly greater compared to the static group for neuroforaminal height (P<0.001). Subsidence was 0% in the expandable group and 32.4% (12/37) in the static group. Conclusion: This study showed significant positive clinical and radiographic outcomes for patients who underwent MIS LLIF using titanium expandable interbody spacers with adjustable lordosis based on significant changes in VAS back pain scores, ODI scores, and radiographic parameters at 12month follow-up. There was a 0% subsidence rate in the expandable group, compared to a 32% subsidence rate in the static group.