NeuroTalk Support Groups - Another surgery

Sooo...
Im not sure how many surgeries ive had since the fiasco of sep 08, but im sure its in the double figues. :o

But last week, I was admitted after my GP AND my local hospital surgeon doctor person both diagnosed papilledema.
I was then referred to Great ormond street, who looked at my eyes under dialation and a proper opthamology machine thing. Surprise...There was no papilledema :Oops::Oops:

...But my hospital continued to investigated the 'Strange' headache I was getting and the continuous nausea.
They put me onto ICP monitoring which was done under general anesthetic a few days after arriving at hospital, I was kept on it for 2 days.
In that time my junior neurosurgeon ( who I say, was the most gorgeous guy in medical history to have ever have stepped foot into a hospital:p:p) could surely tell, that I wasnt suffering from high pressure, infact the complete opposite.

My reading whilst lying down ranged from 3 to 9.
Whilst sitting up however, these dropped alot. Which ranged from -13 to -21.

So its came to the conclusion that my fixed shunt is draining the right amount, and is working a little too hard.
Therefore currently, on wednesday I'm being readmitted for valve exchange on Thursday. They want to put in a programmable valve this time round to see if this sorts it out.

But what im finding difficult to understand is that, at the moment when Im lying down, my pressure is at a perfect level. The second they turn that valve down so that im not overdraining whilst im upright, im not going to be draining as much when im lying flat, giving higher pressure whilst im sleeping.
Unless of course they put in an antisiphon device.

Im just wondering if anyone else has had a similar problem and whether these prgrammables come with an antisiphon.