Spinal degenerative diseases constitute an increasing public health issue attributed to the aging demographic and the load placed on the lumbar spine during routine activities. The implantation of interbody cages is a surgical procedure designed to achieve vertebral fusion and stabilize the segment under physiological loads. Nonetheless, the torsional performance of these implants is not sufficiently documented. This study examines the biomechanical response of swine lumbar segments (L1–L5) subjected to quasi-static torsional payloads, contrasting to the performance of samples with and without a titanium interbody prosthesis positioned between L3 and L4. Each specimen underwent a torsion test at a constant angular velocity of 15°/min until structural collapse or the machine’s maximum torque of 50 N · m was reached. The findings indicated that the prosthesis enhanced system stiffness by 9% and reduced the range of motion by 7.5%. The endplate cartilaginous layer is a crucial area where failure typically begins. The data recorded during the test indicate that the material and geometry of the implant significantly influence load distribution and spinal integrity under rotational stress.