hello, first of all:
the normal pressure in a human cerebrospinal fluid is between 90 and 120 mmHg!
A vp shunt with valve MAYBE needed but not obligatory after an Arnold-Chiari malformation!
The decision to insert or not is helped by an intraventricular pressure measurement, less by the lengh of the frontal horns (done in other types of hydrocephalus!)
why? Because in my opinion, a patient with Arnold-Chiari malformation treated with decompression at age of 50 is no longer requiring a VP-shunt because this patient was in a hydrolic equilibrium despite the form of his/her ventricules! That what your mom created through years؛ she did a ''climatization''. I am not aware about her symptoms before the surgery, but maybe the VP-shunt was not needed or the VP-shunt was just needed but without a skull base decompression procedure, one of them was suffucient!
She had a vp shunt with valve inserted but maybe that valve was not functioning until an incident like a head shaking or trauma happened during her last hospital stay or maybe the valve is too sensitive it changes settings near an MRI device or near a mobile phone...
Most of valve could be regulated between 30 and 200 mmHg.
if a valve is set on 60 mmHg thats mean WHENEVER THE PRESSURE IS ABOVE 60, THE VALVE WILL DRAIN FLUID ! thats mean that your mom at the lowest valve settings she was draing too much! At the time when she needs to be not drained at all! So the settings should be the highest lets say 150... Now once she has a valve inserted (plus anti-syphon device implanted) i will not tell you to remove, but let the NS just stop its functioning by setting it to the highest barier, I mean 170-200, then wait and see. Let him forget about the shape of the ventricules on the CT scan because it has little to say for the patient who had a very large ventricules for almost 50 y. Your moms neural pathways were formed during years in a shape to maintain good voltage indepandently of the shape of her ventricules.
The remnant question is: what your mom presented before the discovery of her ACM, and does she really had a symptomatic ACM (not just an incidental finding) to be treated at age of 50?
Does her symptoms were a ACM???
You are welcome for any further information. Please expect a normal state in 5 days after valve closure. She will be fine :)
Your mom's case is a teaching case for the whole world.
Nassim Abi Chahine, Medhelp Medical Expert in Neurosurgery, International Neurosurgery Forum
Thanks so much for your input- I really appreciate it. To give a bit more info- mom had many neurological issues for a large portion of her life before they were able to finally diagnose the ACM. We will never know if she really needed the shunt because she had the decompression surgery two days after having the shunt placed. Either way, her symptoms and quality of life were dramatically improved post both of those procedures. Not really sure that I understand what you mean by setting the shunt to its highest barrier- her current setting is a 2.5, which we were told is the lowest (meaning draining the least amount of fluid) that it could go. Her ns said the next option may be to somehow close off the shunt completely. Not sure if this is commonly done, or if there are any risks involved with this.
Thanks again!