[frank 05 f-150]

i have four broken plugs on a 05 f-150 crew cab, 5.4 3v triton engine, the fact is the electrode, the half porcelain and the electrode still in the head, so i can´t remove the porcelain center, just the nut and the upper porcelain half came out.... so, any idea how i can do the job with out taking out the heads? thank you