Early Clinical Outcomes Comparing Porous PEEK, Smooth PEEK, and Structural Allograft Interbody Devices for Anterior Cervical Discectomy and Fusion
Background: Recently, material surface advancements have been promoted to improve spinal implant osseointegration. While rough and porous titanium implants have gained traction due to their osteoconductive properties, polyetheretherketone (PEEK) devices have remained popular due to their radiographic properties and similar modulus of elasticity to bone. However, traditional smooth PEEK devices elicit fibrous tissue responses leading to poor implant osseointegration. Recently, PEEK implants have been developed with surface porosity allowing for direct bone in-growth. Despite preclinical data suggesting implant osseointegration with porous PEEK implants, comparative clinical results between implants with and without porous surface architecture are heretofore reported. The objective of this single-site retrospective study was to comparatively evaluate early clinical efficacy in patients undergoing ACDF treated with porous PEEK interbody implants to patients treated with structural allograft or traditional smooth PEEK implants. Methods: 167 consecutive patients presenting with cervical degenerative disc disease and radiculopathy underwent ACDF using one of three implants (porous PEEK (Cohere®, NuVasive Inc., San Diego, CA), structural allograft, or smooth PEEK). After preop evaluation and surgery, patients were followed per standard of care 0.5, 1.5, 3, 6, and 12 months post-op. At each time, patient outcomes were measured by disability (Neck Disability Index) and pain (visual analogue score (VAS) neck/arm pain). Results: Patients treated with porous PEEK implants achieved significantly greater NDI and neck pain improvement by 6 weeks post-op when compared to patients receiving structural allograft or smooth PEEK devices. These significantly greater NDI and neck pain improvements for patients treated with porous PEEK devices compared to structural allograft and smooth PEEK were sustained through 12 months post-op. Conclusion: 12 month follow-up data in patients with degenerative disc disease and radiculopathy demonstrates a clear benefit of porous PEEK in promoting improved early outcomes over structural allograft and smooth PEEK in ACDF procedures.