Shunt Dependency Syndrome after Cyst-Peritoneal Shunt Resolved by Keyhole Microsurgical Cyst Resection: Two Case Reports and Literature Review

Objective  Shunt dependency syndrome after cyst-peritoneal (CP) shunt is a rare but serious complication which leads to increased intracranial pressure and neurological deficit. The possible mechanism still remains in controversy. We present our experience on the treatment of the complication and attempt to find a better therapy strategy for the complication. Methods  Two children with middle fossa arachnoid cysts underwent CP shunt with fixed pressure catheters at an opening pressure of 7 cmH 2 O and then developed dependency syndrome. Both patients were effectively treated by mini-invasive cyst wall excision with the shunts reserved. The clinical manifestation, radiological findings, treatment methods, and therapeutic outcomes were reviewed retrospectively. Results  The time from shunt surgery to shunt dependency syndrome occurrence was 4 and 2 years, respectively. Computed tomography/magnetic resonance findings of the brain showed remarkably collapsed cysts with normal or small ventricles. Both patients underwent secondary mini-invasive cyst wall excision and shunt catheters were reserved. After the operations, their symptoms were resolved except one case with marginally improved visual impairment. Conclusion  Shunt dependency syndrome is a rare but dangerous complication of CP shunt and should be treated in time. Collapsed and thickened cyst wall intermittent covering the catheter head end, decreased brain compliance due to chronic fibrosis, as well as regression of cerebrospinal fluid absorption could be the pathogenesis. We suggest keyhole resection of the residual cyst wall as an effective and mini-invasive treatment option.