shunt blockage

Me best friend has been diagnosed with hydrocephalus at age 54. She has undergone 4 surgeries due to the fact that the shunt keeps blocking. The doctor said the blockage was from fat and pus. They put her on antibiotics and/or replaced the shunt but it seems to keep happening approximately every 3 weeks. Prior to surgery she can barely talk, extremely tired and her cognitive abilities are low. After the surgery her energy returns, she is speaking well and her cognitive abilities are much better. The doctor can not continue to operate on her every 3 weeks. Has anyone else experienced this problem or heard of any solutions with regards to the blockage.