Spine Journal - 2026-06-25 - Journal Article
3D-Printed Porous Titanium versus Polyetheretherketone Cages in Lumbar Interbody Fusion: A Prospective, Multicenter, Randomized Controlled Trial with Bone Mineral Density Stratification.
Shin JW, Park MS, Kwon JW, Kim SH, Seo J, Kim HS, Suk KS, Moon SH, Park SY, Lee BH
Topics
Key Takeaway
In osteoporotic patients undergoing single-level lumbar interbody fusion, 3D-printed porous titanium cages reduced subsidence rate from 58.3% to 12.5% compared to PEEK, with a T-score cut-off of -2.4 (AUC 0.865) identifying patients at elevated PEEK subsidence risk.
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Summary
This multicenter RCT compared 3D-printed porous titanium versus PEEK cages in single-level lumbar interbody fusion, stratifying patients by preoperative BMD. Overall fusion rates were equivalent (92.9% vs. 92.6% per-protocol, p=1.000), but overall subsidence was significantly lower with 3D-Ti (7.1% vs. 37.0%, p=0.010). In the osteoporotic subgroup, PEEK subsidence reached 58.3% versus 12.5% for 3D-Ti (p=0.039), with corresponding inferior VAS back pain and ODI scores in the PEEK cohort.
Key Limitation
The osteoporotic subgroup contained only 8 patients per arm, making the 58.3% vs. 12.5% subsidence comparison statistically underpowered and vulnerable to type I error despite reaching p=0.039.
Original Abstract
BACKGROUND CONTEXT
3D-printed porous titanium (3D-Ti) cages are an alternative to polyetheretherketone (PEEK) cages in lumbar interbody fusion; however, prospective comparative evidence evaluating biomechanical performance in compromised bone quality remains limited.
PURPOSE
To compare radiologic and clinical outcomes of 3D-Ti versus PEEK cages in single-level lumbar interbody fusion, focusing on the impact of bone mineral density (BMD) on structural stability.
STUDY DESIGN
Prospective, multicenter, randomized controlled trial
PATIENT SAMPLE
Sixty-six patients with degenerative lumbar disease were randomized to the PEEK (n=32) or 3D-Ti group (n=34); 55 patients completed the 2-year follow-up.
OUTCOME MEASURES
The primary outcome was the 2-year CT-based fusion rate. Secondary outcomes included cage subsidence, sagittal parameters, disc height index, VAS, ODI, MCID achievement rate, and complications.
METHODS
Patients were randomized 1:1 to receive a PEEK or 3D-Ti cage. Blinded evaluators assessed radiographic outcomes. Per-protocol analysis was conducted for patients who completed the 2-year follow-up. Patients were stratified by preoperative T-scores into normal, osteopenia, and osteoporosis subgroups. Interaction regression and receiver operating characteristic (ROC) curve analyses identified subsidence risk thresholds.
RESULTS
Baseline demographics were comparable. At 2 years, overall fusion rates were comparable between the 3D-Ti and PEEK groups (92.9% vs. 92.6%, p=1.000;
ITT
76.5% vs. 78.1%, p=1.000). However, the overall subsidence rate was significantly lower in the 3D-Ti group (7.1% vs. 37.0%, p=0.010). Outcomes were comparable in normal bone quality, but profound differences emerged in osteoporosis. Osteoporotic PEEK patients exhibited a significantly higher subsidence rate than 3D-Ti patients (58.3% vs. 12.5%, p=0.039), translating to inferior VAS back pain (p=0.012) and ODI scores (p=0.018). Subsidence depth correlated with lower T-scores in PEEK (rho=-0.68, p<0.001) but not 3D-Ti. ROC analysis identified a T-score cut-off of -2.4 (AUC 0.865) for predicting elevated subsidence risk with PEEK.
CONCLUSIONS
While PEEK and 3D-Ti cages provide comparable fusion rates and outcomes in normal bone, 3D-Ti cages demonstrate significantly superior subsidence resistance in osteoporotic patients
CLINICAL TRIAL REGISTRATION
Clinical Research Information Service (CRIS), No. [KCT-0006624].