trepanning
  套孔
  Tre·pan, v. t. & i. [imp. & p. p. Trepanned p. pr. & vb. n. Trepanning.]  Surg. To perforate (the skull) with a trepan, so as to remove a portion of the bone, and thus relieve the brain from pressure or irritation; to perform an operation with the trepan.
  trepan
       n 1: a surgical instrument used to remove sections of bone from
            the skull [syn: trephine]
       2: a drill for cutting circular holes around a center
       v : cut a hole with a trepan, as in surgery
       [also: trepanning, trepanned]