Incarcerated herniation of the cervical spinal cord after laminectomy for an ossification of the yellow ligament.

A 74-year-old man showed a spastic gait and myelopathy in both the hands. Computed tomography revealed an OPLL on C3 and C4, bony spurs on the dorsal side of C4-C6, and an OYL on C3 and C4. We scheduled a two-stage decompression for both the OPLL and OYL. First, we performed laminectomy on the C3-C6 segments and resected the OYL. We did not observe any dural tear or CSF leakage in the dura. The patient's neurological symptoms improved. After the laminectomy, his myelopathy recurred. Postoperative MRI showed a spinal cord herniation. We had the C3/4 anterior cervical disectomy and fusion as we planned. In addition, we performed a surgery to repair the damaged dura mater at the site of spinal cord herniation at the same second surgery. The integrity of the arachnoid membrane was preserved. The patient's myelopathy gradually improved. There have been no reports on postoperative neurological deterioration caused by spinal cord herniation associated with a dural defect at the laminectomy site, without dural tear in the surgery after the resection of a posteriorly located cervical OYL. The possibility of a dural defect in OYL cases should be considered when planning a laminectomy for the resection of the OYL.