It's usually taken to mean that they can, in some circumstances,
execute you, but not torture you or humiliate you.
I tend to think that this would put paid for your plans for the
surviving Tsarneav brother that involved cutting off body parts. Not
only the parts you mentioned, but noses and ears as well. I think.
It would probably mean that hanging, shooting, and electrocution are
acceptable, but pressing, gibbeting or crucifixion would not be.
I also once heard that this referred to a specific kind of punishment
that may have included amputation, but no cite and I haven't found
that anywhere else.