Hi Betty The new osv11 was brilliant for approx 11 months but they only changed the valve itself on initial revision, unfortunately the valve stopped working again so I went in to the same hospital again.I was put under so they could check it all upon waking up I found they had removed the valve & tubing to my abdomen & replaced it all that was nearly 2 years ago & I havent looked back apart from the short term memory problems I was left with after my Medtronic pile of crap caused me. As i have said b4 it was life changing if not life saving to have the Osv11 fitted as it is if only the N.S didnt think they were God & listened to the patient we would all get a better life.You have to go outside your area to get an independent opinion but it is well worth it if I had my way they should BAN Medtronic Stata Valves they are 2 troublesome.Keep in contact if I can help let me know Ian