A Systematic Review of SMART Implantable Devices for Spinal Implants: Current Insights and Future Trends

(1) Background: SMART spinal implants combine biomechanical stabilization with embedded sensors for continuous in vivo monitoring of spinal loading and implant behaviour. This systematic review summarizes current SMART implant technologies in spinal surgery and evaluates their potential clinical applications. (2) Methods: A structured literature search was conducted in PubMed and Scopus in December 2025. Two independent reviewers screened studies using predefined criteria, with data extracted on implant design, sensor type, study model, and application; risk of bias was assessed using the Office of Health Assessment and Translation tool. (3) Results: Thirty-four studies met inclusion criteria, including sensor-integrated posterior rods and fixators (n = 16), vertebral body replacements (n = 6), intervertebral cages or disc space sensors (n = 7), and other configurations (n = 5). Devices were tested in human, cadaveric, and animal models. Most systems used strain-based sensors to quantify implant loading, while few employed accelerometers or pressure sensors. Reported results demonstrated activity- and posture-dependent load changes, and several studies indicated potential for monitoring spinal fusion progression by monitoring load trends. (4) Conclusions: Overall, SMART spinal implants primarily support biomechanical monitoring and show promise for real-time assessment of implant performance, though further studies correlating sensor data with clinical outcomes are required.