Hemimyeloschisis associated with hydrocephalus.

Hemimyeloschisis is a very rare congenital malformation of the spine which is characterized by a split cord malformation associated with complete exposureof the one hemicord to the exterior. We report a case of hemimyeloschisis on the right hemicord in a patient with hydrocephalus. The patient was a female neonate with myeloschisis, skin defect, and hypertrichosis visible at birth in the upper lumbar region. There was also skin defect around the myeloschisis. Computed tomography (CT) revealed a bony septum at the L2 level as well as the myeloschisis on the right hemicord, which enabled us to make a precise preoperative diagnosis of this rare malformation. There was also mild hydrocephalus in cranial CT scan. Closure of the myeloschisis and removal of the septum were successfully performed associated with the closure of the skin in one stage surgery to prevent subsequent infection and neurological deterioration. Ventriculoperitoneal shunt insertion was performed for hydrocephalus. The presence of combined split cord malformation and myeloschisis is consistent with the hypothesis of an ontogenic basis of development. This combination also emphasizes the importance of early imaging for diagnosis in this complex malformation.