David S,
When I was comparison shopping, I read that the perineal approach (
between scrotum and anus) is good for guys who are heavy, because you
avoid going through a thick abdomenal fat pad. The word  "peritoneal"
refers to the abdomenal cavity.
Steve U

hi david - one of the reasons that the RPP isn't favored as compared to
the RRP and LRP is because of the after effects of nerve sparing.

as been discussed many times here, the more times the erection nerves
are disturbed, stretched, stripped, or tampered with, the more problems
one has with potency afterwards.

it was best described that the RPP can be viewed as picturing the
prostate being a that of a boxcar sitting on set of railroad tracks -
which is the erection nerves.

now, spread the tracks and pull the enlarged boxcar that may be twice
the size through them.  one can only imagine the complications that
would arise from some an adventure.

the RRP and LRP are viewed as opening up the patient and lifting the
boxcar off of the tracks - leaving the tracks undisturbed as much as
possible.

~ curtis

knowledge is power - growing old is mandatory - growing wise is optional    
"Many more men die with prostate cancer than of it. Growing old is
invariably fatal. Prostate cancer is only sometimes so."
http://community.webtv.net/PALMER_ENT/doc