Emergency Help Needed!
Dried out lucky bamboo!

I have three lucky bamboos, this is the 4th or 5th year that I've had them. I have them in a glass vase in water, and in all these years i have only added some water to the vase from time to time, never changed the water and the water was always clean and clear. They have grown almost to the ceiling and they were very healthy.

Now the problem!:
About a month ago i suddenly realized that they don't look healthy and straight as usual and I was shocked when I found the empty dry vase!! :(( I don't know for how long it has been dried out but it must have been a couple of days since it was completely empty. I immediately filled the vase with water but in two weeks time there was no change, they looked very weak and the leaves were facing down, although still green; and I found out the water is not clear after two weeks and it smells for the first time in years, so i changed the water again and washed and cleaned the roots (the glass vase narrows as it gets to the bottom, so the roots are very compact and densely stuck together). By that time they were so week that I had to tie them to something so they could stand straight and don't faint.

Now after another week still no progress; they are still weak (actually weaker) and the water is getting unclear again. and i think the tip of the leaves are beginning to become dry :((

I believe that by the time the vase was empty the roots were dried and damaged so they don't function properly and also make the water unclear.

Now my question is that is there any way to save my bamboos? what happens if I cut the roots off from like 10 cm above them! will they have new roots again or they will die?

Please please please someone help!! I don't want to lose them!