The Delta Valve: a physiologic shunt system.

PS Medical has advanced the state-of-the-art in hydrocephalus valve technology with the introduction of the Delta Valve. The Delta Valve is designed upon the premise that the shunted patient should have intracranial pressure (ICP) maintenance within a normal range regardless of cerebrospinal fluid (CSF) flow rate or body position. All previous valves have performance characteristics that are greatly influenced by the negative hydrostatic pressure caused by the gravitational effect on the vertical water column in the distal catheter. This negative pressure influence is non-physiologic and contributes directly to overdrainage that can cause slit ventricles, subdural hematoma, and proximal catheter occlusions. The Delta Valve is the only valve that maintains a near-constant pressure gradient regardless of flow rate or patient posture. It automatically adjusts for increasing negative pressures in the distal catheter by proportionally increasing its resistance to flow, thus nullifying the adverse effects of the hydrostatic force on intracranial pressures. The result is a shunt system that provides for CSF drainage while allowing the patient's normal physiologic conditions to control ICP. The early use of the Delta Valve in the treatment of hydrocephalus may reduce the incidence of the dramatic complications associated with overdrainage.