Cervical spondylosis, a prevalent orthopedic condition affecting countless patients, has long been treated with anterior cervical discectomy and fusion (ACDF) as the gold standard for degenerative disc diseases. The procedure aims to restore spinal stability, reconstruct disc height, and optimize cervical alignment, thereby alleviating symptoms and improving quality of life.

In ACDF surgeries, the conventional "cage-plate" (CP) system —combining titanium plates with interbody cages—has been widely adopted due to its excellent postoperative stability, high fusion rates, and effective correction of cervical curvature. The titanium plate prevents graft displacement and cage subsidence, ensuring robust bony fusion. However, this approach is not without drawbacks, including complications like dysphagia, tracheoesophageal injuries, and plate migration, which have prompted clinical scrutiny.

The Rise of Zero-Profile Standalone Devices

To address these limitations, standalone cages emerged as an alternative, though challenges persisted in maintaining stability and correcting spinal alignment. This led to the development of zero-profile integrated devices , which merge polyetheretherketone (PEEK) cages with a thin titanium alloy plate. Their compact design minimizes contact with anterior soft tissues, reducing esophageal compression and surgical dissection, thereby lowering dysphagia rates.

Recent studies suggest zero-profile implants achieve comparable clinical and radiological outcomes to CP systems in single- and multi-level ACDF, with fewer complications. However, debates continue regarding their efficacy in multi-segment cases, particularly in restoring cervical alignment and preventing subsidence.

Comparative Study Design

A retrospective analysis evaluated 63 patients undergoing two-level ACDF for degenerative disc disease between December 2006 and February 2015. Participants were divided into CP (n=32) and zero-profile (n=31) groups, matched for preoperative characteristics. Key exclusion criteria included prior cervical surgery or inadequate follow-up.

Notably, the zero-profile group demonstrated significantly shorter operative times ( P=0.043 ), suggesting procedural efficiency. Both groups predominantly involved C5/6 and C6/7 levels, with no statistical differences in preoperative kyphosis ( P=0.936 ).

Clinical Implications and Surgical Evolution

The progression from standalone grafts to CP systems marked significant advancements in ACDF, yet multi-level fusions revealed escalating complication risks. Zero-profile devices respond to this need by unifying structural support into a low-profile implant, reducing tissue trauma while preserving stability.

For two-level ACDF, these devices offer equivalent stability to CP systems with diminished soft-tissue irritation. Precise implantation—positioning the titanium plate flush with vertebral edges—is critical to maximize biomechanical performance and alignment correction.

Limitations and Future Directions

This single-center retrospective study acknowledges potential selection bias and limited follow-up duration. Larger prospective trials are needed to validate long-term outcomes, including fusion stability and adjacent-segment degeneration. Further research should explore:

1. Long-term radiographic and clinical outcomes
2. Performance in patients with osteoporosis or spinal instability
3. Biomechanical comparisons using finite element analysis
4. Patient-reported quality-of-life metrics

Conclusion

Zero-profile implants present a promising alternative to CP systems in two-level ACDF, achieving similar efficacy with reduced operative time and complication rates. Their success hinges on meticulous surgical technique, particularly optimal device positioning. While long-term data remain essential, these innovations signify a shift toward minimally invasive, patient-tailored cervical spine surgery.