Tethered brainstem repair and near-fatal ventriculoperitoneal shunt insertion. Case report.

The authors report a case of primary brainstem tethering, a component of a spinal dysraphic state, occurring in a 13-year-old girl. This patient also had associated hydrocephalus, a low-lying tethered cord, and a syrinx in her conus medullaris. The significance of imaging surveys of the craniospinal region and head in a case involving a low-lying tethered cord is highlighted. The insertion of a ventriculoperitoneal shunt, leading to traction on the tethered brainstem, proved nearly fatal for this patient. In cases involving a multiple-level tethered cord, the sequence of detethering should be decided on with caution. It seems prudent to detether the vital neural structure first, so as to minimize the traction force on that structure. All four previously reported cases of secondary tethered brainstem and cerebellar vermis in the literature are reviewed and compared with the present case of primary brainstem tethering. The literature describing brainstem dysfunction caused by ventricular drainage is also reviewed.