[Two cases of failure of a programmable pressure valve]

Two cases of a programmable pressure valve trouble are reported. Case #1 was that of a 49-year-old male who had received a ventriculoperitoneal shunt (VPS) using a Sophy programmable pressure valve (Model S3) after the removal of the fourth ventricle ependymoma. After the VPS, the patient went through several episodes of complaining of headache due to the spontaneous movement of the rotor from the high pressure position to the medium or low pressure position. The symptom had disappeared after exchanging the valve for a new one and by setting the valve pressure at high. Examination of the removed valve revealed that the bending-degree of the spring tip was insufficient, and that the opening pressures at the medium and high pressure positions were both lower than the desired range. Case #2 was that of a 62-year-old female who had received a VPS for normal pressure hydrocephalus using a Sophy programmable pressure valve (Model S3) with the valve pressure set a high. However, her symptoms did not improve, so an attempt was made to change the valve pressure from the high pressure position to the medium pressure position with a ring magnet. But the rotor could not be moved. The valve was exchanged and the valve pressure was set at medium, and the symptoms of the patient improved postoperatively. Examination of the removed valve revealed that the movement of the rotor with a ring magnet was not able to be carried out smoothly.(ABSTRACT TRUNCATED AT 250 WORDS)