Impact of Cage Placement on Vertebral Endplate Cyst Formation and Bone Union in Transforaminal Lumbar Interbody Fusion.

Study DesignRetrospective cohort study.ObjectivesTo determine the ideal cage placement position in transforaminal lumbar interbody fusion (TLIF) surgery to prevent vertebral endplate cyst (VEC) formation and improve bone union rates.MethodsThis study retrospectively analyzed 69 patients who underwent TLIF, and 88 intervertebral levels were observed. Patients were categorized into peripheral, central, and mixed types based on the cage placement. The incidence of VEC formation and endplate injuries (EIs) were assessed using computed tomography 1 year postoperatively. Factors associated with VEC formation and non-union, including patient demographics, clinical data, cage placement, Hounsfield unit values, and intraoperative EIs, were analyzed.ResultsVECs occurred in 55.7% of surgical levels and were significantly associated with non-union ( < .001). Center-type cage placement was a strong predictor of VEC formation ( = .028, OR = 16.3, 95% confidence interval [CI]: 1.36-195.0), along with EIs ( = .003, OR = 5.86, 95% CI: 1.80-19.0). In contrast, pre-existing VECs appeared to have a protective effect ( = .046, OR = 0.272, 95% CI: 0.076-0.979).ConclusionsCage placement in the central region significantly increases the risk of VEC formation and non-union. Periphery-type placement may be preferable to reduce endplate damage and improve fusion outcomes. Preventing EIs and optimizing cage positioning are critical to minimize VEC formation. Further prospective studies are needed to refine surgical strategies and improve long-term outcomes following TLIF.