Severe heterotopic ossification in a seronegative spondyloarthritis patient after cervical Bryan disc arthroplasty: A case report

Figure 1 Herniation of the intervertebral disc at the C4-C5, C5-C6, and C6-C7 levels.

Figure 2 Postoperative cervical radiographs in the dynamic (flexion and extension) and anteroposterior views. AP: Anteroposterior.

Figure 3 C3-C4 herniation of the intervertebral disc with spinal cord compression in the fourth year after the operation.

Figure 4 Initial X-rays at four years after the motorcycle accident. Left: Shiny corner sign, a sclerotic margin of the T-L vertebral body corner, compatible with seronegative spondyloarthropathy; Right: Bone sclerotic change in the bilateral sacroiliac joint, compatible with bilateral sacroiliitis, grade I.

Figure 5 Pre-operative and postoperative radiographs during follow-up.

Figure 6 Cervical computed tomography images showing anterior spur formation without spinal canal stenosis. February 2014: 1.5 years after the first operation; August 2016: 4 years after the first operation; September 2017: 1 year after the second operation.