A trephine (pronounced /trɪˈfaɪn/) is a surgical instrument with a cylindrical blade used to cut out circular sections of bone or other tissue. The term derives from the Greek word τρύπανον (trypanon), meaning "instrument for boring."
Design and Function
A trephine consists of a hollow cylinder with a toothed or serrated lower edge, designed to rotate and cut a circular core of tissue. Many designs include a central guide pin to help position the instrument and a transverse handle for manual rotation. Trephines come in various dimensions and designs depending on their intended surgical application.
Medical Uses
Trephines are used in several distinct medical procedures:
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Cranial surgery: A trephine can be used to cut a circular opening in the skull, a procedure related to trepanation or trephination. This allows access to the brain for surgical intervention or the relief of intracranial pressure.
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Bone biopsy: A bone marrow trephine is specially designed to obtain a cylindrically shaped core of bone and bone marrow. This core sample is typically examined in a histopathology laboratory under a microscope to assess the pattern and cellularity of the bone marrow. This is a useful diagnostic tool in conditions such as bone marrow cancer and leukemia.
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Corneal surgery: A trephine may be used to cut a round piece of the cornea for certain eye surgical procedures.
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Osteochondral procedures: In orthopedic contexts, trephines can be used to core out bone, such as in procedures involving osteochondral lesions, where the instrument may be cannulated to facilitate removal of bone from a specific area.
Historical Context
The trephine is closely related to the trepan, and both instruments are associated with trepanation—one of the oldest known surgical procedures, involving the deliberate drilling or scraping of a hole into the human skull. The use of a circular trephine or crown saw was described in detail by Hippocrates, and by the time of the first-century Roman medical writer Celsus, the instrument had a retractable central pin and a transverse handle. The term "trephine" is attributed to English surgeon John Woodall, who used it in his 1639 text The Surgeon's Mate.
Related Terms
- Trepan: A similar instrument for boring holes, particularly in the skull.
- Trepanning / Trephination: The surgical procedure of creating a hole in the skull using a trepan or trephine.
- Craniotomy: A broader surgical procedure involving the temporary removal of a bone flap from the skull, which may involve the use of a trephine.
References
- Holmes, Oliver Wendell. Medical Essays (2008).
- Liddell, Henry George; Scott, Robert. A Greek–English Lexicon (Perseus Project).
- Merriam-Webster Dictionary, "Trephine."
- Collins English Dictionary, "Trephine."
- National Cancer Institute Dictionary of Cancer Terms, "Trephine."
