Interspinous soft stabilization (ISS) is a dynamic approach to managing lumbar degenerative disorders, focusing on preserving motion while providing segmental stability. Utilizing artificial ligaments to mimic the biomechanical properties of the posterior ligament complex (PLC), ISS addresses limitations of rigid spinal fusion, such as increased stress on adjacent segments and loss of mobility. Biomechanical studies have demonstrated that ISS effectively restores over 80% of native spinal stiffness and reduces adjacent segment stress by 20–30%. These findings highlight its potential to provide stability without compromising the natural kinematics of the lumbar spine. ISS achieves critical biomechanical goals, including motion preservation, load redistribution, and the maintenance of sagittal alignment. By reducing excessive flexion and extension instability, ISS stabilizes the spine while maintaining dynamic load-sharing mechanisms. Furthermore, ISS minimizes stress concentrations on intervertebral discs and facet joints, promoting balanced load distribution across treated and adjacent segments. Experimental evidence demonstrates ISS’s effectiveness in maintaining rotational and flexion–extension stability under various physiological loads. These biomechanical properties underscore the value of ISS as a motion-preserving alternative to rigid fusion, offering a scientifically grounded solution to lumbar instability. By addressing key biomechanical challenges, ISS optimizes stabilization while minimizing the risk of adjacent segment degeneration.