Subsidence Rates Associated With Porous 3D-Printed Versus Solid Titanium Cages in Transforaminal Lumbar Interbody Fusion
Nathaniel Toop, Joravar Dhaliwal, Andrew J. Grossbach, David Gibbs, Nihaal Reddy, Alexander Keister, Noah Mallory, David S. Xu, Stephanus Viljoen
Abstract
Study Design Retrospective Cohort Study. Objective To determine whether 3D-printed porous titanium (3DPT) interbody cages offer any clinical or radiographic advantage over standard solid titanium (ST) interbody cages in transforaminal lumbar interbody fusions (TLIF). Methods A consecutive series of adult patients undergoing one- or two-level TLIF with either 3DPT or ST “banana” cages were analyzed for patient reported outcome measures (PROMs), radiographic complications, and clinical complications. Exclusion criteria included clinical or radiographic follow-up less than 1 year. Results The final cohort included 90 ST interbody levels from 74 patients, and 73 3DPT interbody levels from 50 patients for a total of 124 patients. Baseline demographic variables and comorbidity rates were similar between groups ( P > .05). Subsidence of any grade occurred more frequently in the ST group compared with the 3DPT group (24.4% vs 5.5%, respectively, P = .001). Further, the ST group was more likely to have higher grades of subsidence than the 3DPT group ( P = .009). All PROMs improved similarly after surgery and revision rates did not differ between groups (both P > .05). On multivariate analysis, significant positive correlators with increasing subsidence grade included greater age ( P = .015), greater body mass index ( P = .043), osteoporosis/osteopenia ( P < .027), and ST cage type ( P = .019). Conclusions When considering interbody material for TLIF, both ST and 3DPT cages performed well; however, 3DPT cages were associated with lower rates of subsidence. The clinical relevance of these findings deserves further randomized, prospective investigation.