PMC9062959_01
A lateral radiograph of the cervical spine shows the presence of ossification along the anterior and posterior aspects of the vertebrae.
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F1
The brain MR ruled out a stroke, while a lateral radiograph of the cervical spine showed both diffuse idiopathic skeletal hyperostosis (DISH) and OPLL [Figure 1].
(a) The ossified mass lies anterior to the K-line as demonstrated by the sagittal CT cut (b), (c) Axial CT cuts showing ossified posterior longitudinal ligament decreasing the space available for the cord.
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F2
The cervical CT further showed hyperdense mixed OPLL that was continuous from C2-C5 and segmental at C6-C7, along with DISH from C2 to C7 [Figure 2]. Due to the presence of a positive K-sign [Figure 2] (i.e., a vertical line drawn between mid-canal points opposite C2 and C7 - if the OPLL mass falls anterior to that line, it is termed as the positive K-sign), the presence of multiple level OPLL, and an adequate cervical lordosis, the patient was managed with laminectomy and posterior fusion.
Postoperative radiographs show the final construct.
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F3
The construct was completed with rods and bone graft fusion was achieved from C1 to C6 [Figure 3].
(a) MRI at presentation demonstrating cord compression due to the OPLL mass with effacement of the anterior thecal sac. (b) MRI at a follow-up of 1 year showed improvement in the cord compression and a reduction in the myelomalacia cord changes. OPLL: Ossification of the posterior longitudinal ligament.
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F4
One year later, the patients' modified Japanese Orthopaedic Association score improved to 13, and the MRI showed adequate cord decompression with a reduction of the intrinsic cord myelomalacia [Figure 4].