Anterior lumbar interbody fusion implants: a narrative review of current trends and future directions.

Abstract

Background and objective: Anterior lumbar interbody fusion (ALIF) is a safe and effective type of lumbar interbody fusion (LIF) technique. Each LIF technique requires implants specifically designed to accommodate its distinct anatomical corridor and dimensional constraints. This narrative review is about the implants used for ALIF. Specifically, what materials are used to create the implants, and how those properties collectively contribute to arthrodesis. It also summarizes the role of additive manufacturing, also known as 3D printing, in the creation of the next generation of ALIF implants.

Methods: Relevant articles were identified through a comprehensive search of PubMed and Google Scholar, using keywords like "Anterior Lumbar Interbody Fusion (ALIF)", "ALIF Implants", "3D-Printed Implants", "Medical Applications of 3D Printing", "Off-the-Shelf (OTS) Implants", "Patient-Specific Implants". Only peer-reviewed, English-language publications discussing implant materials, properties, or 3D printing integration for ALIF were included.

Key content and findings: Titanium and polyetheretherketone (PEEK) are the primary materials used in ALIF implants. Recent advances in 3D printing technology can create implants with specific design features previously unattainable with conventional methods, which can improve their overall durability and utility. These 3D-printed implants can be customized in terms of porosity, stiffness, and surface texture to promote fusion, increase implant longevity, and support indirect decompression. 3D printed patient-specific implants are now available. Implants are built to specifically match the computed tomography or magnetic resonance imaging rendering of the patient's anatomy.

Conclusions: ALIF is a safe and effective procedure for patients with appropriate indications. The anatomical corridor utilized in ALIF allows for the placement of implants with a large footprint, which, along with specific implant properties, contributes to the high fusion rates associated with this technique. Advances in 3D printing technology now enable the production of titanium and PEEK ALIF implants with enhanced design features, further improving the procedure's safety and efficacy profile.