I just found this while surfing around.
http://www.gender.org.uk/conf/2002/thomas22.htm (http://www.gender.org.uk/conf/2002/thomas22.htm)
Interesting that he says narrowing is the problem from lack of dilating, not loss of depth as I've always heard. Actually, that makes sense.
A lot of the other stuff boils down to: The better condition you are in when you go into surgery, the less likely you will have complications.
- Kate