Postoperative Delirium After OLIF-PPSF Versus TLIF: A Propensity Score-Matched Analysis over 16 Years

Background/Objectives: Postoperative delirium is a clinically important complication after lumbar fusion surgery, yet whether the choice of fusion technique influences its occurrence remains unclear. We compared the incidence of postoperative delirium between oblique lateral interbody fusion with percutaneous pedicle screw fixation (OLIF-PPSF) and transforaminal lumbar interbody fusion (TLIF). Methods: The medical records of 850 patients (335 OLIF-PPSF, 515 TLIF) treated between 2008 and 2023 were retrospectively reviewed; 487 patients were eligible, and propensity score matching yielded 141 matched pairs. Delirium was identified through symptom-triggered psychiatric consultation rather than routine screening. Analyses were stratified by treatment era and repeated within the period in which both procedures were performed. Results: Delirium occurred in no OLIF-PPSF patient and in 9 TLIF patients (6.4%; risk difference 6.4%, 95% CI 2.4-11.7%; McNemar exact p = 0.004; adjusted odds ratio 19.82, 95% CI 1.20-326.53). However, OLIF-PPSF was performed only from 2017 onward, whereas 118 of the 141 matched TLIF operations (83.7%) preceded 2017, and all events occurred during 2008-2014. Within 2017-2023 no delirium occurred after either procedure (0/168 versus 0/34). Conclusions: Although delirium was less frequent after OLIF-PPSF, every event preceded its introduction, and none occurred after either procedure once both were performed contemporaneously. The difference cannot be attributed to the surgical approach and more likely reflects changes in perioperative care over time. These findings are exploratory.