musa basjoo banana tree

I have one of these and I can't find any information on how to prune the leaves. I cut off the dead brown ones, but now the trunk is getting skinnier and weaker. Is there a certain way to prune these?
Please help before it bends in half.

 

Check out The International Banana Society. They know much about this sort of stuff.

 

Your musa basjoo banana tree may nead some soppurt so you might want to stablise it with wood. Also you might want to put mulch around your banana tree, also they nead lots of water, lots of fertilizer to grow big and strong.