Finite element analysis of two-level discontinuous cervical hybrid revision surgery strategy to reduce biomechanical responses of adjacent segments

JOR Spine, 2024 · DOI: 10.1002/jsp2.70008 · Published: October 10, 2024

Simple Explanation

This study investigates the best surgical method for correcting problems after a previous neck surgery (ACDF) that led to degeneration in segments above and below the fused area. It uses computer models to test different combinations of fusion, zero-profile devices, and artificial discs. The goal is to find a revision surgery (RS) that reduces stress on the adjacent segments and prevents further degeneration. The study compares five revision surgery models with different combinations of cages, zero-profile devices, and artificial discs to identify the most biomechanically favorable option.

Study Duration

Not specified

Participants

CT scans of a 30-year-old female participant without cervical disease

Evidence Level

Not specified

Key Findings

1
The D-C-D model, which uses artificial discs at both adjacent levels, showed the most significant reduction in biomechanical stress compared to other revision surgery models.
2
The P-C-P model, using zero-profile devices, was slightly better than the traditional cage-plus-plate model in reducing biomechanical responses.
3
The D-C-D model demonstrated a ROM distribution closest to the intact spine, suggesting a more natural biomechanical behavior post-revision surgery.

Research Summary

This study uses finite element analysis to compare different hybrid revision surgery strategies for two-level discontinuous adjacent segment degeneration (ASD) following anterior cervical discectomy and fusion (ACDF). The results suggest that a hybrid approach using cervical disc arthroplasty (CDA) at both adjacent levels (D-C-D) provides the best biomechanical outcomes, reducing stress and restoring more natural motion. The P-C-P construct is biomechanically superior to the conventional C-C-C construct, and can be the best recommendation when it does not meet the indications for CDA.

Practical Implications

Surgical Planning

The D-C-D model may be considered as a good surgical option for patients undergoing revision surgery for two-level discontinuous ASD.

Device Selection

Surgeons can consider using a zero-profile device in patients who do not meet the indications for CDA as it provides improved biomechanics compared to traditional cage-plus-plate constructs.

ASD Prevention

The study emphasizes the importance of selecting surgical strategies that minimize stress on adjacent segments to prevent recurrent ASD.

Study Limitations

1
The cervical spine FE model used in the study was based on cervical spine generation in a single healthy individual.
2
The feasibility of the established model is assessed through a comparison with previously published data and has not undergone actual in vitro validation.
3
Our cervical spine model utilizes a bilayer structure consisting of cortical and trabecular bone, with fixed and uniform thickness and material properties for each layer.

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