Safety and biological effectiveness of transforaminal (TLIF) and oblique lumbar interbody fusion (OLIF): a retrospective cohort study including patients with significant comorbidity

The aim of the study was to compare the safety, perioperative outcomes, and radiographic fusion rate of oblique lumbar interbody fusion (OLIF) and transforaminal lumbar interbody fusion (TLIF) in patient population including highly comorbid patients who underwent lumbar fusion for degenerative pathology. This retrospective cohort study included 268 patients who underwent one- or two-level lumbar interbody fusion (L3–L5) between 2017 and 2021. 201 patients underwent TLIF and 67 received OLIF surgery. Demographic, operative, postoperative clinical, and radiographic data were collected. One-year CT and X-ray scans in a subset (n = 157 and n = 174) were used to evaluate bony fusion. Adverse Events (AEs) were categorized using the SAVES-V2 system. Multivariate logistic and linear regressions models were applied to identify predictors of AEs and LOS. Baseline characteristics were comparable between groups. OLIF demonstrated significantly reduced intraoperative blood loss, minor perioperative decline in serum Hgb and shorter hospital stay, whereas TLIF had shorter operative times. Early postoperative AEs and reoperation rates did not differ significantly. High-comorbidity patients showed similar safety profiles. The overall one-year fusion rate was high in both groups (CT: 90.9% TLIF vs. 91.5% OLIF on CT- and 92.5% in TLIF, 87% in OLIF on X-ray based measurements). OLIF achieved fusion more frequently within the cage, whereas TLIF more often demonstrated fusion around the cage. Independent predictors of AEs included age, anthropometric factors, and intraoperative blood loss. The regression model showed good discriminatory ability (AUC = 0.735). Both OLIF and TLIF are safe and effective techniques for the surgical treatment of degenerative lumbar conditions also in medically complex patients. OLIF offers advantages in blood loss and LOS, while TLIF allows shorter operative times. Surgical approach should be individualized based on patient anatomy and surgeon expertise.