10-Year trend of lateral lumbar interbody fusion and the impact of 3D-printed titanium in a high-volume academic center.

PURPOSE: The aim of this study is to evaluate utilization trends of standalone (SA) lateral lumbar interbody fusion (LLIF) and circumferential (360) LLIF after the transition from polyetheretherketone (PEEK) to 3D-printed titanium (3DTi) at a high-volume academic center.

METHODS

We retrospectively reviewed all LLIF procedures performed at a single center from 2014 to 2023, assessing trends in SA-LLIF utilization and cage material choice (PEEK vs. 3DTi). A regression analysis with an interaction term assessed changes in SA-LLIF trends following 3DTi implementation (2017/2018). SA-LLIF rates were compared between 3DTi adopters and a surgeon who continued using PEEK in pre- (2014-2017) and post-transition (2019-2023) periods using chi-square tests.

RESULTS

A total of 1836 patients (3,257 levels) were included, with 41.6% (764 patients; 1332 levels) undergoing SA-LLIF. Three surgeons adopted 3DTi cages in 2017-2018, while one continued using PEEK. During the post-3DTi-transition period, SA-LLIF utilization showed an annual increase of 11% (p = 0.007), while a non-significant downward trend was noted for the surgeon who continued using PEEK. Among 3DTi adopters, SA-LLIF utilization was higher in the post-transition period (44.8% in 2019-2023 vs. 28.3% in 2014-2018, p < 0.001), with no significant change for the surgeon who continued using PEEK. This upward trend was also observed in patients with osteoporosis, obesity, degenerative scoliosis, and prior laminectomy (all p < 0.05).

CONCLUSION

SA-LLIF utilization was significantly higher in the period after 3DTi adoption. These patterns are consistent with the hypothesis that the biomechanical properties of 3DTi cages could support broader use of SA-LLIF in a wider patient population, although causality cannot be established from this study.