[Postoperative spinal cord herniation diagnosed by metrizamide CT: a case report].

A 55-year-old man came to our hospital, complaining of progressive deterioration of gait disturbance 13 years following C4-7 laminectomy. Neurological examination showed marked spastic gait, hyperreflexia in the lower limbs, ankle clonus, hypesthesia below C5, and loss of position and vibratory sensations in great toes. Preoperative metrizamide CT clearly demonstrated pseudomeningocele and cervical cord herniation through the dural defect at C6-7 and narrow canal at C3. Moreover, sagittal and coronal reconstructions reveal a clear-cut posterior displacement of the cervical cord with posterior protrusion of the cord through the possible dural defect and the obvious extent of pseudomeningocele. At the operation, herniation of the posterior aspect of the cord through the dural defect at C6-7 was encountered as well as pseudomeningocele from the leakage at the C5 level. The cause of spinal cord herniation is classified into i) congenital, ii) traumatic, iii) iatrogenic. An iatrogenic spinal cord herniation is rare and its preoperative diagnosis used to be hard. Discussion was made on the points of preoperative diagnosis of a postoperative spinal cord herniation by metrizamide CT.