Gravitational shunt valves in hydrocephalus to challenge the sequelae of over-drainage

In hydrocephalus treatment, ventriculo-peritoneal shunts (VPS) have become the most relevant therapy for seven decades among other treatment options. Due to the hydrostatic pressure in vertical position, CSF diversion is somehow non-physiological. The integration of gravitational valves in VPS was established to counteract the hydrostatic draining force and to approach a physiological condition of the cerebrospinal diverting system. Numerous clinical studies have shown that gravitational valves are able to reduce secondary complications of VPS treatment. It remains a challenge for the treating neurosurgeon to select the correct valve resistance based on individual anatomies and different etiologies of hydrocephalus as well as varying levels of activity of the patient.

This review covers the development of gravitational shunt valves from historical, theoretical and clinical aspects for pediatric and adult etiologies of hydrocephalus. We discuss the role of gravitational shunt valves in preventing over-drainage issues and present the state-of-the-art literature. Furthermore, ongoing prospective trials are presented.

Counteracting the hydrostatic force by selecting the correct valve in a VPS system to achieve physiological balance in CSF diversion during vertical and horizontal body changes has become the current standard for hydrocephalus management. Gravitational shunt valves reliably address this need to minimize over-drainage events in the vertical position without affecting the CSF flow in the horizontal position. The results of ongoing prospective studies on the safety and efficacy of adjustable gravitational valves are still pending. Due to the complexity of the CSF flow, lifelong follow-up care for patients with VPS is critical.