Biomechanical Role of Lumbar Spine Ligaments in Flexion and Extension: Determination Using a Parallel Linkage Robot and a Porcine Model

STUDY DESIGN: Porcine lumbar spine specimens were cyclically loaded in flexion and extension with a pure moment. The resistance to flexion and extension of the individual spinal elements was quantified using a sequential resection procedure. OBJECTIVE: To determine the biomechanical contribution of the individual posterior spinal ligaments, including the interconnections between the supraspinous and interspinous ligaments, to resisting flexion-extension moments applied to the lumbar spine. SUMMARY OF BACKGROUND DATA: Numerous experimental studies have performed repeated tests with sequential resection to determine the role of spinal ligaments. Most studies have not maintained the kinematics across trials, and therefore these studies have assessed the kinematics and kinetics of injured spines rather than delineating the mechanics of individual ligaments. METHODS: The L4-L5 motion…