perforate vs trephine

perforate

verb
  • To pierce; to penetrate. 

  • To make a line of holes in (a thin material) to allow separation at the line. 

adj
  • perforated 

trephine

verb
  • To perforate with a trephine. 

  • To use a trephine during surgery. 

noun
  • A surgical instrument with a cylindrical blade used to remove a circular section of tissue, f.e. bone or cornea; a trepan. 

How often have the words perforate and trephine occurred in a corpus of books? (source: Google Ngram Viewer )