Retrograde Partial Migration of Ventriculoperitoneal Shunt with Chamber: Review of Causative Factors and Its Prevention.

Distal migration of shunt is a very common occurrence. Proximal migration of shunt is rare and possible pathophysiological mechanisms to explain this unusual complication is rarely attempted. A 5-month-old child shunted for posttraumatic hydrocephalus presented 1.5 years later with raised intracranial pressure and seizures. Imaging showed subdural hygroma, partial intracranial migration of shunt/chamber. On endoscopy, choroid plexus was adherent to shunt tip and some pericranial tissue was found in the anchoring suture (intraventricularly displaced). Shunt was retrieved endoscopically and diversion established by endoscopic third ventriculostomy with symptoms free follow-up. Host-related and surgical factors have been postulated. Tug-of-war effect on the anchoring suture and collapsing cortex are the possible mechanisms that explain proximal migration in our case. Three-point fixation of the chamber to pericranium, small burr hole with a smaller durotomy, can prevent shunt migration. Proximal shunt migrations should be dealt with endoscopy so as to avoid complications.