Can an iPhone 4 screen be repaired while the back is smashed?

I have purchased an iPhone 4 screen replacement from eBay and plan to install it myself. Although, while the screen was on its way, I dropped my phone and the back glass smashed.

If I try to remove the back glass, will it fall to pieces, or will it stay together for me to be able to remove it, replace the front screen, and then put the back glass back on?

The back glass is held together with two screws on the bottom. If they back is taken out all the parts will stay inside the phone. There's nothing attached to the back glass.you'll be fine. But it depends on the how bad the glass is smashed. If its just a couple of scratches then the white/black part should be enough to hold it. I suggest putting tape over it to hold it down and to protect your hand. The screen can be installed since the back has to be removed anyway.