I have had my second opinion & am now getting my strata adjustable valve removed due to the huge amount of problems with it re adjusting itself so when you are told that they cannot do it do not believe it. It seems that the manufacture of this shunt & the neuro people do not want to admit there is a problem probably due to the liability they may end up with.All i can suggest is that anyone suspecting there is a problem, get an independant second opinion as you as the person with this unit will well know when things are not right.I am going to have an Integra OSV11 shunt fitted if any one has any experiences with these i would love to hear from you.