Secondary sacral tethered cord syndrome after treatment of secondary cervical syringomyelia.

A female patient operated at the age of 11 on a pilocytic astrocytoma in the posterior fossa, was re-operated for a recurrence 9 years later. A Torkildsen drain was placed in the 4th ventricle and she remained asymptomatic for 15 years before presenting again with acute hydrocephalus, tonsillar herniation, and a massive cervicothoracic syrinx. The symptoms retreated following craniocervical untethering and decompression. Two weeks later, however, she suffered from debilitating radiculopathy provoked by tethering of the cauda equina. Again, symptoms retreated completely after microsurgical intervention. This combination of a secondary Chiari-like malformation with cervical syringomyelia and tethering of the cauda equina in a single patient as a delayed complication of posterior fossa surgery has not been reported before. Diagnosis and treatment of lower tethered cord syndrome may be obscured and delayed in complex clinical situations. In particular, awareness to symptoms that are not related to syringomyelia is important in patients with a known syrinx and a history of posterior fossa surgery.