Biomechanics of Spinal Fixation in Metastatic Disease

Abstract

Modern decision-making in the treatment of spinal metastasis is dependent on multiple patient-specific factors, including neurologic function, tumor type, spinal biomechanics, and systemic disease. Instrumented spinal fixation has been a proven treatment modality for spinal metastasis to preserve neurologic function and achieve biomechanical stabilization. However, surgical spinal fixation continues to evolve as both primary and adjunctive treatment for spinal metastasis. In this chapter, we provide an up-to-date synopsis of all biomechanical considerations in the modern-day treatment of spinal metastasis with instrumented fixation. We will discuss the different types of instrumentation and implant technology widely utilized in metastasis surgery, including pedicle screws and interbody cages and graft material. We will review different approaches to all areas where spinal metastasis may arise and the unique biomechanical considerations of spinal fixation with each. Finally, the biomechanics of newer and less invasive approaches to metastasis surgery will be described, including minimally invasive approaches and separation surgery. Spinal instrumentation for spinal metastasis is a growing and ever-changing field, and the biomechanics of traditional and new stabilization strategies must always be considered in surgical planning.