Answer: trephined

AnswerCrossword Clue
trephinedto operate upon with a trephine
trephinedTREPHINE, to operate on with a surgical saw, also TREPAN, TRAPAN
trephinedsmall circular saw with a center pin mounted on a strong hollow metal shaft to which is attached a transverse handle: used in surgery to remove circular disks of bone from the skull