Porous Cage Macro-Topography Improves Early Fusion Rates in Anterior Cervical Discectomy and Fusion

Area of Science:

• Spine surgery
• Orthopedic implants
• Biomaterials

Background:

• Anterior cervical discectomy and fusion (ACDF) aims to alleviate pain and neurological symptoms by achieving bony fusion.
• The correlation between fusion rates and clinical outcomes after ACDF is not fully understood.
• Novel interbody cage designs with macro-topographic and porous features aim to enhance bone-implant integration and promote early fusion.

Purpose of the Study:

• To compare clinical outcomes and computed tomography (CT)-evaluated fusion rates between traditional NanoMetalene™ (NM) cages and NanoMetalene™ cages with machined porous features (NMRT).
• To assess the impact of cage design on the speed and quality of bony fusion after ACDF.

Main Methods:

• A prospective, observational, nonrandomized cohort study included 89 patients undergoing ACDF.
• Patients received either NM cages (n=41) or NMRT cages (n=48).
• Clinical outcomes (VAS, NDI, SF-12) were assessed preoperatively and at 3 and 6 months postoperatively. CT scans at 3 and 6 months evaluated fusion using Bridwell grading.

Main Results:

• Both cage types showed significant improvement in clinical outcomes from baseline to 6 months.
• The NMRT group exhibited significantly higher CT fusion rates at 3 months (79% vs. 56%, p=0.02) compared to the NM group.
• At 6 months, fusion rates were similar (NMRT: 83% vs. NM: 78%, p=0.69), but the NMRT group showed a trend towards higher fusion quality (mean Bridwell grade 1.4 vs. 1.8, p=0.08).

Conclusions:

• NMRT cages demonstrated superior early fusion rates at 3 months post-ACDF compared to NM cages.
• The improved early fusion with NMRT suggests enhanced cage integration.
• Early CT assessment at 3 months may be sufficient for evaluating fusion in patients receiving NMRT cages, potentially allowing for earlier return to activity.