This 48-year-old male patient underwent artificial disc replacement (ADR) at C6-C7 for foraminal stenosis 2 years earlier with another surgeon. His pain was reduced by 50% and he did reasonably well until approximately 6 months ago.
He describes a gradual onset of paresthesias and “buzzing” in the left trapezial region (~80% of his symptoms), right upper neck pain (~20% of his symptoms) that radiates into the right paracervical region with diffuse aching of the mid to inferior axial neck region. Furthermore, he indicates decreased energy and fatigue, and has stopped his P90X workouts (the patient thought the workouts helped reduce symptoms), and reports chronic pain has negatively impacted his enjoyment of life.
Current Pain on Visual Analogue Scale (0 to 10)
- Neck pain is a 3 becoming a 7
- Left trapezial pain is a 2 becoming an 8
There is no myelopathy or radicular symptoms. Pain in the left trapezius worsens with sitting and/or cervical flexion lasting longer than five to 10 minutes. He reports cervical extension is “okay.”
Case Discussion from Dr. Lali Sekhon
Dr. Corenman describes an interesting case of a complication from implantation of a Prestige® cervical artificial disc that led to recurrent symptoms, subsidence, and loss of motion. The procedure was salvaged successfully with explantation and interbody fusion.
Several points are worth discussing:
1. Only a 50% reduction in pain after the index procedure is not typical for the outcome for this procedure. To my mind, it suggests inadequate decompression of the uncovertebral joints with persisting stenosis.
2. No x-rays are available immediately after the initial surgery, which was performed elsewhere. The technique necessitates minimal endplate preparation. Subsidence should only occur if the bone quality is poor, excessive endplate resection occurs, or oversizing the implant overloads the interspace. Any or all of these factors would lead to subsidence, loss of motion, and foraminal collapse with focal kyphosis. The x-rays suggest the level has ankylosed.
3. Revision was possible because of the nature of the artificial disc device. Unscrewing the superior and inferior segments allowed easier disarticulation. Devices with rails or keels would necessitate partial or complete corpectomies or explantation.
In short, the author demonstates the perils of poor surgical technique with artificial disc implantation that can lead to radiological and clinical failure. Excessive endplate preparation, potentially oversizing the implant in relation to the interspace, or pre-operative bone quality issues can all lead to endplate failure. Well salvaged.