Role of Titanium Cages in Anterior Cervical Discectomy and Fusion (ACDF)
Titanium cages are the preferred option for interbody fusion in ACDF procedures due to their biologically inert properties, excellent fusion rates, and ability to provide immediate structural stability while minimizing complications. 1
Advantages of Titanium Cages in ACDF
- Biologically Inert Properties: Titanium offers an ultra-structurally smooth surface that doesn't provide adherence for organisms, making it particularly valuable in surgical settings 1
- High Fusion Rates: Studies demonstrate fusion rates of 95-97.6% with titanium cages in ACDF procedures 2, 3
- Immediate Stability: Provides immediate internal orthosis and protection of neural elements 1
- Avoidance of Donor Site Morbidity: Eliminates complications associated with autograft harvesting 2
Clinical Outcomes with Titanium Cages
Titanium cages in ACDF procedures have demonstrated excellent long-term outcomes:
- 80% excellent or good outcomes by Odom's criteria in long-term follow-up (5-8.3 years) 2
- Low complication rates with negligible surgery-related complications 4
- Significant improvement in neurological function post-surgery 4, 5
Types of Titanium Cages
Several titanium cage designs are available for ACDF:
- Cylindrical Threaded Cages: Provide good long-term results with high fusion rates 2
- Rectangular Stand-alone Cages: Standard option with good surgical outcomes and minimal complications 4
- Box-shaped Cages: Effective for fusion but may have subsidence concerns at specific levels 6
- Mesh Cages (TMCs): Used particularly in corpectomy procedures, can be filled with autograft 3
Technical Considerations
Cage Positioning and Sizing
- Optimal Position: Cage should be adjusted to the anterior vertical line to minimize subsidence 4
- Appropriate Sizing: Cage size significantly impacts subsidence rates 4
- Avoid Excessive Distraction: Higher distraction ratios correlate with increased cage subsidence 4
Subsidence Concerns
Subsidence is a potential complication with titanium cages:
- Occurs in approximately 19-23% of cases 4
- More common at C6-C7 level 6
- May lead to early deterioration of local angle and cervical alignment 4
- Modified cage designs with extended contact surface may reduce subsidence into C7 6
Imaging Follow-up After ACDF with Titanium Cages
Post-operative imaging is essential to evaluate fusion and potential complications:
- Initial Assessment: Radiographs immediately post-operation 6
- Follow-up Imaging: At 3 and 6 months post-operation 6
- Fusion Evaluation: Lateral flexion-extension radiographs at 6 months 6
- CT for Complex Cases: CT is the most sensitive and specific modality to assess spinal fusion and can detect adjacent segment degeneration 1
Multi-level ACDF vs. Corpectomy with Titanium Cages
When comparing multi-level ACDF with anterior cervical corpectomy fusion (ACCF) using titanium cages:
- Both procedures show good clinical outcomes and high fusion rates 3
- Multi-level ACDF has lower blood loss and shorter operative time 3
- ACCF has slightly higher rates of early hardware failure and pseudarthrosis 3
- In the absence of specific pathology requiring vertebral body removal, multi-level ACDF with titanium cages may result in lower morbidity 3
Adjacent Segment Degeneration
Long-term follow-up shows:
- Asymptomatic adjacent disc degeneration in approximately 50% of patients 2
- Symptomatic adjacent disc degeneration in only 5% of patients 2
- Additional surgery required in only 2% of cases 2
In conclusion, titanium cages represent an excellent option for ACDF procedures, providing high fusion rates, good clinical outcomes, and avoiding donor site morbidity associated with autografts. Proper cage selection, positioning, and sizing are critical to minimize potential complications such as subsidence.