Overshunting-Associated Myelopathy Treated with Endoscopic Third Ventriculostomy

Overshunting-associated myelopathy (OSAM) is a rare complication of cerebrospinal fluid shunt placement. Previous reports have recommended removal or ligation of the shunt and use or revision of a pressure programmable valve to treat OSAM. We present a rare case of OSAM successfully treated with endoscopic third ventriculostomy (ETV).

A 67-year-old female who had undergone ventriculoperitoneal shunting with a constant pressure valve for long-standing overt ventriculomegaly in adults 42 years ago presented to our department with bilateral hand numbness. Magnetic resonance imaging of the cervical spine showed spinal canal stenosis and dilatation of the paravertebral venous plexus with spinal cord compression. Cervical laminoplasty was temporarily effective, but her symptoms reoccurred and worsened. ETV was performed, and a programmable shunt valve adjusted to maximum pressure was also interposed as a safety device. Her symptoms immediately improved after this operation. Cervical magnetic resonance imaging and computed tomography showed that the cervical paravertebral venous dilatation had also resolved immediately. Clinical improvement was maintained with no recurrence of hydrocephalus or paravertebral venous dilatation for 2 years postoperatively.

This is the first case of OSAM treated with ETV. ETV might be a useful treatment option for OSAM after treatment for obstructive hydrocephalus.