Rare Posterior Dislocation of Mobi-C Cervical Disc: A Case Report and Surgical Resolution

Area of Science:

• Neurosurgery
• Orthopedic Surgery
• Biomedical Engineering

Background:

• Cervical disc prosthesis (CDP) offers motion preservation for degenerative disc disease, reducing adjacent segment issues compared to ACDF.
• While effective with low failure rates, rare complications like prosthesis migration can occur.
• Posterior migration of a CDP is exceptionally rare, with limited literature documenting such events.

Purpose of the Study:

• To report a unique case of posterior intraprosthetic dislocation of a Mobi-C prosthesis.
• To contribute knowledge regarding this rare complication of cervical disc replacement.
• To evaluate the efficacy of salvage surgery for this complication.

Main Methods:

• A case report of a 50-year-old female patient who underwent Mobi-C implantation at C6-C7 for cervical disc herniation.
• Postoperative follow-up including imaging (CT) to diagnose the complication.
• Revision surgery involving removal of the dislocated prosthesis and conversion to ACDF with the Anchor C system.

Main Results:

• The patient initially experienced symptom relief but later presented with neck pain and right upper limb numbness after 2.5 years.
• CT imaging revealed posterior migration of the polyethylene insert, causing spinal cord compression.
• Revision surgery successfully resolved symptoms, with proper implant alignment and no complications.

Conclusions:

• Posterior intraprosthetic dislocation of the Mobi-C prosthesis is an extremely rare complication.
• ACDF serves as an effective salvage procedure for this complication, as demonstrated by long-term follow-up.
• Further research into failure mechanisms and improved CDP designs is warranted to prevent such occurrences.