The intervertebral fusion cage is a large, hollow cylinder made of high-grade metal, typically titanium. It is engineered as a "cage" structure, allowing bone graft materials to be placed within the hollow cylinder. This design facilitates spinal fusion between two vertebrae, as the strategic perforations throughout the cage permit bone formation around and through the device, creating a solid biological connection.

Modern intervertebral fusion cages are versatile, supporting both traditional open incision surgery and advanced laparoscopic procedures. While open surgery provides direct visibility for the surgeon, the laparoscopic approach utilizes smaller incisions and specialized camera equipment, often resulting in reduced tissue damage and faster patient recovery times.

Functionally, the cage serves two primary roles: first, it restores the appropriate spacing between vertebrae, enlarging the nerve root openings and tightening surrounding ligaments to reduce instability and mechanical pain. Second, it replaces the disc and maintains correct spinal alignment until permanent bone fusion is achieved.