title: Overdrainage of cerebrospinal fluid caused by detachment of the pressure control cam in a programmable valve after 3-tesla magnetic resonance imaging.
abstract: The authors report a rare case of overdrainage of the CSF caused by the malfunction of a Codman-Hakim programmable valve (CHPV) following a 3-T MR imaging procedure. Nine years ago this 72-year-old woman underwent ventriculoperitoneal shunt placement with a CHPV system for hydrocephalus due to subarachnoid hemorrhage. The postoperative course was uneventful and the system functioned well. A radiograph obtained immediately after 3-T MR imaging revealed that the pressure control cam in the valve system was detached from the base plate. Intracranial hypotension syndrome occurred several hours after the MR imaging study, and a CT scan revealed a decrease in ventricle size. A revision of the system promptly resolved the symptoms, and a postoperative CT scan revealed that the ventricle size was restored to normal. Examination of the extracted valve showed a Y-shaped crack in the plastic housing as well as detachment of the white marker and cam from the base plate. A reduction in the power of the flat spring to press the valve ball led to CSF overdrainage because of a loss of support by the cam. Because the patient had incurred no head injury during the day and radiographic studies of the system 5 years previously had shown detachment of the white marker, damage to the system might have been caused by a past impact. These facts may indicate that the antimagnetic performance of the system could have decreased due to a previous impact and that the strong magnetic force in a 3-T MR imaging environment might have caused detachment of the cam.
authors.affiliation: Department of Neurosurgery, Seguchi Neurosurgical Hospital, Kamisato Kuroda, Iida, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Watanabe
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Seguchi
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Hongo
mesh_terms: D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology; D002552:Cerebral Ventricles / Q000473:pathology; D014695:Cerebral Ventriculography; D002555:Cerebrospinal Fluid; D004322:Drainage / Q000295:instrumentation*; D004868:Equipment Failure; D005260:Female; D006801:Humans; D006849:Hydrocephalus / Q000209:etiology / Q000601:surgery; D019585:Intracranial Hypotension / Q000000981:diagnostic imaging / Q000209:etiology* / Q000628:therapy; D008279:Magnetic Resonance Imaging / Q000009:adverse effects*; D011312:Pressure; D013345:Subarachnoid Hemorrhage / Q000150:complications / Q000601:surgery; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D017287:Ventriculoperitoneal Shunt / Q000295:instrumentation*