Insufficient sagittal endplate-bone graft contact is a risk factor for high-grade cage subsidence occurring after lateral lumbar interbody fusion supplemented with lateral plate: An analysis of 122 cases

Abstract

Background Lateral lumbar interbody fusion (LLIF) is a minimally invasive fusion technique that can be performed with lateral plate. Insufficient contact between the endplate and bone graft in the fusion segment may result in instability and subsequent cage subsidence. This study aimed to investigate the potential correlation between endplate-bone graft contact and high-grade cage subsidence (HCS) occurring after LLIF supplemented with lateral plate. Method Between June 2017 and February 2023, 122 patients (47 males, 75 females; mean age 62.7 years; minimum follow-up period 12 months) undergoing LLIF supplemented with lateral plate were retrospectively reviewed. The incidence of HCS was assessed, and patients were categorized into HCS group or non-HCS group based on the occurrence of HCS. Comparative analyses were performed on demographic characteristics, surgical variables, and parameters related to endplate-bone graft contact between the two groups. Multivariable logistic regression analysis was employed to identify the potential risk factors associated with HCS. Results The HCS group comprised 13 patients, while the non-HCS group included 109 patients. The incidence of HCS occurring after LLIF supplemented with lateral plate was 10.7%. The sagittal contact rate of endplate-bone graft (OR, 0.844; 95% CI, 0.766–0.931; P < 0.001) and inferior cage-endplate angle (OR, 1.869, 95% CI, 1.215–2.873, P = 0.004) were determined to be significantly correlated with HCS occurring after LLIF supplemented with lateral plate. Compared to non-HCS group, the patients in HCS group had a lower sagittal contact rate of endplate-bone graft and a larger inferior cage-endplate angle. Conclusion The incidence of HCS occurring after LLIF supplemented with lateral plate was 10.7%. HCS was significantly associated with insufficient sagittal endplate-bone graft contact. Further study aiming to optimize the sagittal endplate-cage contact in the procedure of LLIF supplemented with lateral plate are warranted to enhance clinical outcomes.