Anti-Siphon Devices Reduce Symptomatic Complications of Ventriculoperitoneal Shunt in Normal Pressure Hydrocephalus Patients

Introduction: Ventriculoperitoneal shunt (VPS) is the mainstay surgical treatment for patients with Normal Pressure Hydrocephalus (NPH). However, complications of VPS, typically relating to over-drainage, can lead to poor outcomes. New VPS devices include anti-siphon valves (ASV’s) that are meant to reduce complications of VPS associated with over-drainage while still maintaining positive shunt responsiveness. We aimed to retrospectively analyze patients with NPH who underwent VPS surgery with and without ASV’s to determine whether ASV’s decrease over-drainage complications associated with VPS while still maintaining response from VPS surgery.

Methods: We retrospectively reviewed patients with suspected NPH who underwent VP shunt surgery at a single academic institution. Patient demographics, post-surgical complications, and VP shunt responsiveness were recorded. Full responders were defined as receiving benefits to the level experienced during the lumbar drain trial at 3 months post-operation. Non-responders included both those who experienced some or no benefit. Symptomatic complications attributed to VPS included falls, headaches with associated symptoms of over-drainage, SDH or hygromas.

Results: Of the 60 patients who underwent VPS surgery, 17 had shunts with ASV’s (median follow up 75 weeks) and 43 has standard shunt placement (median follow up 41 weeks). Patients with ASV’s had similar NPH symptom improvement when compared to patients without ASV’s (p=0.0821). There was no significant difference between patients with ASV’s and those without for subdural hematomas (p=0.661) or hygromas (p=0.490), any type of headache (p=1.00), complications requiring interventions (p=1.00), or ED visits (p=0.0761) when taken individually. However, there were less overall symptomatic complications in patients with ASV’s (Odds Ratio: 3.97, 95% CI: 0.917 to 24.6, p=0.0447) when all complications were grouped together.

Conclusion : ASV’s are associated with overall decreased symptomatic complications when compared to valves without ASV’s for patients with NPH. However, rates of post-surgical complications including subdural hematomas and hygromas, complications requiring intervention, and ED visits remains similar.