Acquired isolated unilateral fourth nerve palsy after ventriculoperitoneal shunt surgery.

Ventriculoperitoneal shunt has been the surgical procedure of choice for many years for both communicating and noncommunicating hydrocephalus.(1) High failure rates and complications have been reported, despite major improvements in shunt technology(2); however, fourth (trochlear) nerve palsy has not been reported after this procedure. We describe 2 patients who developed a fourth nerve palsy after shunt surgery. Recovery was incomplete, and strabismus surgery was required.