[Problems encountered with a programmable pressure valve (SOPHY) positioned in the chest wall]

Sixty-eight hydrocephalic patients were treated with a shunt system that incorporated a SOPHY programmable valve. This device is very effective for treating disorders of CSF circulation. However, when the valve is placed on the scalp, it produces artifacts on MR imaging due to its small magnetic rotor, and may cause necrosis of the scalp above it. On the other hand, when it is positioned on the chest, MR artifacts decrease and exchanging the valve devices becomes easier. Therefore, we have positioned the device on the chest. However, some complications were encountered, such as the turning over of the valve in the subcutaneous pocket and the twisting of the shunt tube. Moreover, the shunt tube may stretch due to growth of the neck during development in infantile patients or extension of the neck during exercise. These complications are associated only with subcutaneous placement on the chest, so we conclude that such a valve, if placed on the chest, should be placed in a lower position on the chest, and if MR examination will not be performed in the foreseeable future, we recommend that it be placed on the occipital scalp, especially in infantile patients.