I asked my doctor if I can just quit having revisions, after my third in 7 days in '06. He said the fluid that won't drain without the shunt, would cause severe dementia, along with the physical symptoms of nausea, pain, etc. as it takes up space in the brain and pushes on important parts of the brain. Of course, everyone is different...but this is just an example. I told him I wanted to quit them if I were much older, this is when he told me about this.
Just the possibility of the dementia and poor quality of life was enough for me to scare me into another shunt if and when I need one. I plan to bypass Lizard's amount of time since last shunt done. (28 years????) I watched my mom with Alzheimer's, and the dementia was devastating to both of us. At times, she was aware of her mental, and emotional, decline, and that alone was so hard to deal with.
She wanted me to sleep with her in her last 4 months, as she had gone back to childhood days, and she had been afraid to sleep alone at that time. Another time she told me I was her mother when I asked if she knew who I was. Everyone knows what Alzheimer's is, it's a type of dementia, but not caused by lack of shunt. Dementia can also cause combativeness when it's advanced. but if your mother can understand she can get Alzheimer symptoms, she may change her mind. I don't mean to scare you, just think this might help convince her. It's scary, and a couple days of discomfort, but you know it's going to go away as you heal.
Good luck. Keep us posted.