Stripped spark plug hole in head!!!HELP

[Premiere Investment Properties,LLC.]

Hi all
I bought a 92 S4 about a year ago, and the car was/is very solid. I went
thru the records and saw it just had a tune up recently from a notable
dealer. Long story short, one of the plugs backed out of the head and in
doing so...Totally stripped any threads in the head along the way, not to
mention destroy the coilpack as well.
My question is, does the head have to come off in order to helicoil the plug
hole or can it be done by someway I am not familiar with.
Any help is appreciated
Thanks
Tim