Footprint mismatch in total cervical disc arthroplasty

Area of Science:

• Spine Surgery
• Biomedical Engineering
• Orthopedic Implants

Background:

• Cervical disc arthroplasty is a common procedure for cervical radiculopathy and myelopathy.
• Implant dimensions are typically based on cadaver studies.
• Optimal prosthetic footprint match is critical for successful surgical outcomes.

Purpose of the Study:

• To evaluate the accuracy of prosthetic footprint match with native cervical endplate dimensions.
• To identify potential size discrepancies in commonly used cervical disc prostheses.

Main Methods:

• Computed tomography (CT) scans of 24 patients (192 endplates) were analyzed.
• Anterior-posterior and mediolateral diameters of cervical endplates were measured.
• Implant dimensions of four common cervical disc prostheses were compared to patient anatomy.

Main Results:

• Over 50% of the largest implant footprints were smaller than the corresponding cervical endplate diameters.
• Inappropriate size match occurred in over 60% of C5/C6 and C6/C7 levels based on anteroposterior diameter.
• A significant percentage of endplates were larger than the most frequently implanted cervical disc devices.

Conclusions:

• A notable size mismatch exists between current cervical disc prostheses and patient anatomy.
• This undersizing may increase risks of subsidence, loosening, and biomechanical failure.
• Surgeons and manufacturers must consider implant sizing for improved safety and efficacy.