When considering interbody material for transforaminal lumbar interbody fusion (TLIF), both standard solid titanium (ST) and 3D-printed porous titanium (3DPT) cages perform well. However, 3DPT cages are associated with lower rates of subsidence. This is the key findings of a recent retrospective study, the findings of which were published in the Global Spine Journal by Nathaniel Toop (Ohio State University School of Medicine, Columbus, USA) et al.
The clinical relevance of these findings deserves further randomised, prospective investigation, say the researchers.
The study sought to determine whether 3DPT interbody cages offer any clinical or radiographic advantage over ST interbody cages in TLIF.
A consecutive series of adult patients undergoing one- or two-level TLIF with either 3DPT or ST ‘banana’ cages were analysed for patient reported outcome measures (PROMs), radiographic complications, and clinical complications. Exclusion criteria included clinical or radiographic follow-up less than one year.
The final cohort included 124 patients (90 ST interbody levels from 74 patients, and 73 3DPT interbody levels from 50 patients). Baseline demographic variables and comorbidity rates were similar between groups (p>0.05).
The study found that subsidence of any grade occurred more frequently in the ST group compared with the 3DPT group (24.4% vs 5.5%, respectively, p=0.001). Further, the ST group was more likely to have higher grades of subsidence than the 3DPT group (p=0.009). All PROMs improved similarly after surgery and revision rates did not differ between groups (both p>0.05).
On multivariate analysis, significant positive correlators with increasing subsidence grade included greater age (p=0.015), greater body mass index (p=0.043), osteoporosis/osteopenia (p<0.027), and ST cage type (p=0.019).