Tonsillar herniation is a rare and seldom reported complication after lumboperitoneal (LP) shunting. There have been only few reports that have presented possible options for treatment with varying degrees of success. In this report, we describe a rare case of tonsillar herniation after LP shunting and review related literature.A 17-year-old girl with hydrocephalus related to a traumatic brain injury underwent implantation of an adjustable pressure shunt (valve setting2.5) and a small lumen peritoneal catheter via the L4-L5 interspinal space. One month later, she was admitted to the emergency room with a Glasgow Coma Scale score ofE1M1Vt and dilated pupil. Image studies demonstrated new-onset tonsillar herniation and a mild cervical syrinx. Emergent suboccipital decompressive craniectomy, C1 laminectomy, and duraplasty were performed. This was followed with ligation of the LP shunt and implantation of a ventriculoperitoneal (VP) shunt a few days later. The patient's Glasgow Coma Scale score gradually recovered to 6, which was her previous neurologic status.Tonsillar herniation as a complication after LP shunting is best treated with decompression, ligation or removal of the LP shunt, and a shift to a VP shunt. The tonsillar herniation should be rapidly addressed to avoid persistent symptoms or progression of the neurologic deficits.
Keywords: Tonsillar herniation; acquired Chiari malformation; lumboperitoneal shunt; syringomyelia.