Can overdrainage of csf fluid cause a vacuum effect?

My son sustained a subdural hemotoma while playing high school football which resulted in a emergency craniotomy. Three months later after his surgery to replace his skull cap he had about a 1/4 inch drop/indentation in his skull where the cap was replaced. It continued without much change for approximately one year. We were told he needed a shunt placed which was done 7 months after the craniotomy do to hydrocephalus. A CT was done at this time. 6 months later another CT was done after he had a gran mal seizure. The radiologist noted significant changes at this time in the craniotomy. My son continued to have headaches and severe neck aches. Another year passed and his complaints were dismissed by his doctor as having "tone". After much insistance another CT was performed 14 months later showing a drop of 3/4 inch in his craniotomy now. After taking my son to another doctor he had suggested that maybe the shunt be clamped off to see if too much csf fluid is causing a vacuum effect. Can this be possible? Can it cause his skull to continue to drop/indent? The CT is showing his skull now pushing on his brain and pushing it over the midline.

[Dr. A. Srivastava]

Thank you for your question. Although without being able to examine him I can not offer you the specific advice on diagnosis and treatment that he needs, but I would try to provide you some relevant information about his health concern.

If he has continuous headache, possible causes may be shunt is either under-draining or over-draining. His doctor can assess this with a lumbar puncture and measures the fluid pressure. He/She may make some adjustment of the shunt to allow it to drain more and can monitor if the headache improve. Another possibility could be shunt is over-draining, that may lead to low CSF pressure that can also lead to headache. This may improve when the person lies down and gets worse when the person sits or stands. Even then if he suffers continuous headache, please arrange an appointment with a neurologist right away who will evaluate the further underlying disorders here that may be the main reasons of her headaches and can suggest her appropriate treatment. Hope this information proves helpful to you.