title: Programmable shunt valves: in vitro assessment of safety of the magnetic field generated by a portable game machine.
abstract: Cerebrospinal fluid (CSF) shunts are frequently used to treat hydrocephalus. The use of a programmable shunt valve allows physicians to easily change the opening pressure. Since patients with adjustable CSF shunt valves may use portable game machines, the permanent magnets in these machines may alter the shunt valve programmed settings or permanently damage the device. This study investigated the risk of unintentional valve adjustment associated with the use of game machines in patients with programmable CSF shunt valves. Four adjustable valves from 4 different manufacturers, Sophysa Polaris model SPV (Polaris valve), Miethke proGAV (proGAV), Codman Hakim programmable valve (CHPV), and Strata II small valve (Strata valve), were evaluated. Magnetic field interactions were determined using the portable game machine, Nintendo DS Lite (DS). The maximum distance between the valve and the DS that affected the valve pressure setting was measured by x-ray cinematography. The Polaris valve and proGAV were immune to unintentional reprogramming by the DS. However, the settings of the CHPV and Strata valves were randomly altered by the DS. Patients with an implanted shunt valve should be made aware of the risks posed by the magnetic fields associated with portable game machines and commonly used home electronics.
authors.affiliation: Department of Neurosurgery, Showa University Fujigaoka Hospital, Yokohama, Kanagawa, Japan. knakashima@med.showa-u.ac.jp
authors.forename: Koji
authors.initials: K
authors.lastname: Nakashima
authors.forename: Takato
authors.initials: T
authors.lastname: Nakajo
authors.forename: Michiari
authors.initials: M
authors.lastname: Kawamo
authors.forename: Akihito
authors.initials: A
authors.lastname: Kato
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Ishigaki
authors.forename: Hidetomo
authors.initials: H
authors.lastname: Murakami
authors.forename: Yohichi
authors.initials: Y
authors.lastname: Imaizumi
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Izumiyama
mesh_terms: D002557:Cerebrospinal Fluid Shunts / Q000009:adverse effects / Q000295:instrumentation*; D003201:Computers / Q000592:standards*; D006801:Humans; D006849:Hydrocephalus / Q000503:physiopathology / Q000628:therapy*; D060526:Magnetic Fields / Q000009:adverse effects*; D013525:Surgical Instruments / Q000009:adverse effects / Q000592:standards*; D014584:User-Computer Interface; D018910:Video Games / Q000009:adverse effects*