[A Case of Onion-Skin Hemifacial Dysesthesia Caused by Ossification of the Cervical Posterior Longitudinal Ligament].

BACKGROUND: The spinal trigeminal nucleus is a cranial nerve which extends caudally from the medulla to the upper cervical segment of the spinal cord. An upper cervical lesion can cause pain or dysesthesia of the face sparing the central area, which is called onion-skin pattern. CASE PRESENTATION: We present a rare case of a 73-year-old man with cervical ossification of the posterior longitudinal ligament(OPLL)causing onion-skin pattern dysesthesia. No other brain lesion was detected by MRI. He had received adequate medication for six months, but his dysesthesia persisted. Cervical radiographic studies showed OPLL with slight instability at the C2-3 level and mild spinal cord compression at the C3 vertebral level. The lesion was considered solely responsible for the onion-skin pattern dysesthesia, and it resulted in posterior cervical decompression. Immediately after the surgery, his dysesthesia disappeared. CONCLUSION: The onion-skin pattern dysesthesia could have been caused by the C2-3 lesion.