Need to trim 12 foot high arborvitea hedge

 I submitted this to the wrong NG before I found this one.


I have a tall arborvitae hedge (12 feet tall) that I trim using a ladder.
I'd like to buy a trimmer on a pole and use that instead.
I wonder if a prunner would work. What I see on the internet looks like a
small chain saw at the end of a pole.
I'd rather get one like that rather than a trimmer that shears because
sometime a thick branch bends out of place a needs cutting.

Besides the sides, the top needs pruning so as not to grow too tall. After a
couple of years those stems get too big for a trimmer.

But I wonder if a chain saw with small teeth can cut the soft growth or will
it just mash it?

Any advice?