trephining

v. (Medicine) perform surgery with a small circular saw for cutting circular discs of bone

Trepanation (also known as trepanning, trephination, trephining or burr hole) is a form of surgery in which a hole is drilled or scraped into the skull, thus exposing the dura mater in order to treat health problems related to intracranial diseases, though in the modern era it is used only to treat epidural and subdural hematomas, as an extreme body modification, and for surgical access for certain other neurosurgical procedures, such as intracranial pressure monitoring.
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Trephine /tre·phine/ 1. a crown saw for removing a disk of bone, chiefly from the skull. 2. an instrument for removing a circular area of cornea. 3. [more]Trephining - Community and Resources

Noun
1. a surgical instrument used to remove sections of bone from the skull
(synonym) trepan
(hypernym) surgical instrument
Verb
1. operate on with a trephine
(hypernym) operate on, operate
(derivation) trephination

(p. pr. & vb. n.)
of Trephine