Proximally situated osseous septum in complex spina bifida. Case report.

In Type I split cord malformation (SCM) lesions, the osteocartilaginous spur and its dural sleeve are almost always located in the caudal extent of the median cleft. The authors present a case of lumbar myelomeningocele associated with a thoracic Type I SCM in which an osseous septum is uniquely situated in the proximal extent of the median cleft. Split cord malformations are cord-tethering lesions, which may be associated with a myelomeningocele that causes additional tethering, even in the opposite direction; therefore, both lesions should be treated. In view of this unique case, however, the surgical approach used for tethering lesions in such cases of complex spina bifida should perhaps be tailored. Whenever feasible, meticulous preoperative examination of a patient with spina bifida, including entire craniospinal magnetic resonance imaging followed with perioperative dynamic evaluation, is important for the effectiveness and safety of the surgery.