Risk Factors and Consequences of Cage Subsidence after Single-level Posterior or Transforaminal Lumbar Interbody Fusion: A Retrospective Multicenter Study

Introduction: Cage subsidence (CS) after posterior or transforaminal lumbar interbody fusion (PLIF or TLIF) is challenging; however, its impact on health-related quality of life (HRQOL) remains unclear. This study aimed to explore the impact of CS occurrence on HRQOL and identify the risk factors in patients following PLIF or TLIF. Methods: A total of 138 patients (mean age, 67 years; follow-up period, 12 months) who underwent single-level PLIF or TLIF were retrospectively analyzed. CS was defined as >1 mm sinking of the intervertebral cage evaluated via computed tomography. The patients were divided into the CS and nonsubsidence (NS) groups. HRQOL was assessed using the Oswestry Disability Index (ODI) scores. Results: <0.001, respectively). Conclusions: The use of two intervertebral cages may enhance initial stability and reduce CS risk after PLIF. Initial intervertebral stability was crucial to preventing CS occurrence, as evidenced by the high occupancy rates of autograft in patients without CS. Surgical factors, including surgical strategy and intraoperative techniques, should be considered to prevent CS occurrence and to improve surgical outcomes and patient satisfaction.