Table 1.

Example of a GMDN Preferred Term for medical devices.

GMDN Code: 35965

GMDN Term Name: Hydrocephalic valve

GMDN Definition: A non-active implantable device that functions as part of a hydrocephalic shunt system and is used to reduce the increased pressure from the excessive accumulation of cerebrospinal fluid (CSF) around the brain, by controlling the flow of the fluid. The operating pressure is typically pre-set prior to implantation (by the manufacturer or the surgeon), and the valve is activated when the ventricular (brain) pressure rises above the pressure setting of the valve. Some valve designs may facilitate re-adjustment of the pressure settings in situ using, e.g. a dedicated programmer.