AskDefine | Define trepan

Dictionary Definition

trepan

Noun

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]

User Contributed Dictionary

English

Etymology 1

from trephine

Noun

  1. A tool used to bore through rock when sinking shafts.
  2. A surgical instrument used to remove a circular section of bone from the skull; a trephine.

Verb

  1. To create a large hole by making a narrow groove outlining the shape of the hole and then removing the plug of material remaining by less expensive means.
  2. To use a trepan; to trephine.

Etymology 2

possibly from treppan, to trap

Noun

  1. A trickster.

Verb

  1. To trick; to ensnare; to seduce.

Extensive Definition

Trepanation (also known as trepanning, trephination, trephining or burr hole) is 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 and for surgical access for certain other neurosurgical procedures, such as intracranial pressure monitoring.
Trepanation was carried out for both medical reasons and mystical practices for a long time: evidence of trepanation has been found in prehistoric human remains from Neolithic times onwards, per cave paintings indicating that people believed the practice would cure epileptic seizures, migraines, and mental disorders. In prehistoric times, trepanation was thought to cure diseases by letting evil spirits escape. The bone that was trepanned was kept by the prehistoric people and worn as charms to keep evil spirits away.
The modern medical procedure of corneal transplant surgery uses a technique known as trepanning or trephining, however the operation is conducted on the eye (not the skull), with an instrument called a trephine.

History

Old World

Trepanation is perhaps the oldest surgical procedure for which there is evidence, and in some areas may have been quite widespread. Out of 120 prehistoric skulls found at one burial site in France dated to 6500 BC, 40 had trepanation holes. Many prehistoric and premodern patients had signs of their skull structure healing; suggesting that many of those that proceeded with the surgery survived their operation.
Trepanation was also practiced in the classical and Renaissance periods. Hippocrates gave specific directions on the procedure from its evolution through the Greek age, and Galen elaborates on the procedure, too.
During the Middle Ages and the Renaissance, trepanation was practiced as a cure for various ailments, including seizures and skull fractures. The survival rate of the operations was high and the infection rate was low.

Pre-Columbian Mesoamerica

In pre-Columbian Mesoamerica, evidence for the practice of trepanation and an assortment of other cranial deformation techniques comes from a variety of sources, including physical cranial remains of pre-Columbian burials, allusions in iconographic artworks and reports from the post-colonial period.
Among New World societies, trephinning is most commonly found in the Andean civilizations such as the Inca. Its prevalence among Mesoamerican civilizations is much lower, at least judging from the comparatively few trepanated crania which have been uncovered.
The archaeological record in Mesoamerica is further complicated by the practice of skull mutilation and modification which was carried out after the death of the subject, in order to fashion "trophy skulls" and the like of captives and enemies. This was a reasonably widespread tradition, illustrated in pre-Columbian art which on occasion depicts rulers adorned with or carrying the modified skulls of their defeated enemies, or of the ritualistic display of sacrificial victims. Several Mesoamerican cultures used a skull-rack (known by its Nahuatl term, tzompantli ) on which skulls were impaled in rows or columns of wooden stakes.
Even so, some evidence of genuine trepanation in Mesoamerica (i.e., where the subject was living) has been recovered.
The earliest archaeological survey published of trepanated crania was a late 19th-century study of several specimens recovered from the Tarahumara mountains by the Norwegian ethnographer Carl Lumholtz. Later studies documented cases identified from a range of sites in Oaxaca and central Mexico, such as Tilantongo, Oaxaca and the major Zapotec site of Monte Albán. Two specimens from the Tlatilco civilization's homelands (which flourished around 1400 BC) indicate the practice has a lengthy tradition.
A study of ten low-status burials from the Late Classic period at Monte Albán concluded that the trepanation had been applied non-therapeutically, and, since multiple techniques had been used and since some people had received more than one trepanation, concluded it had been done experimentally. Inferring the events to represent experiments on people until they died, the study interpreted that use of trepanation as an indicator of the stressful sociopolitical climate that not long thereafter resulted in the abandonment of Monte Alban as the primary regional administrative center in the Oaxacan highlands.
Specimens identified from the Maya civilization region of southern Mexico, Guatemala and the Yucatán Peninsula show no evidence of the drilling or cutting techniques found in central and highland Mexico. Instead, the pre-Columbian Maya seemed to have utilised an abrasive technique which ground away at the back of the skull, thinning the bone and sometimes perforating it, similar to the examples from Cholula. Many of the skulls from the Maya region date from the Postclassic period (ca. 950–1400), and include specimens found at Palenque in Chiapas, and recovered from the Sacred Cenote at the prominent Postclassic site of Chichen Itza in northern Yucatán.

Modern medicine

Trepanation is a treatment used for epidural and subdural hematomas, and for surgical access for certain other neurosurgical procedures, such as intracranial pressure monitoring. Modern surgeons generally use the term craniotomy for this procedure. The removed piece of skull is typically replaced as soon as possible. If the bone is not replaced, then the procedure is considered a craniectomy.

Voluntary trepanation

Although considered today to be pseudoscience, the practice of trepanation for other purported medical benefits continues. The most prominent explanation for these benefits is offered by Dutchman Bart Huges (alternatively spelled Bart Hughes). He is sometimes called Dr. Bart Hughes although he did not complete his medical degree. Hughes claims that trepanation increases "brain blood volume" and thereby enhances cerebral metabolism in a manner similar to cerebral vasodilators such as ginkgo biloba. No published results have supported these claims.
Other modern practitioners of trepanation claim that it holds other medical benefits, such as a treatment for depression or other psychological ailments. In 2000 two men from Cedar City, Utah were prosecuted for practicing medicine without a license after they performed a trepanation on an English woman to treat her chronic fatigue syndrome and depression.
However, individuals may practice non-emergency trepanation for psychic purposes. A prominent proponent of the modern view is Peter Halvorson, who drilled a hole in the front of his own skull to increase "brain blood volume".
trepan in Catalan: Trepanació
trepan in Czech: Trepanace
trepan in German: Trepanation
trepan in Spanish: Trepanación
trepan in French: Trépanation
trepan in Lithuanian: Trepanacija
trepan in Hungarian: Trepanáció
trepan in Japanese: 頭部穿孔
trepan in Polish: Trepanacja
trepan in Portuguese: Trepanação
trepan in Finnish: Trepanaatio
trepan in Swedish: Trepanation
trepan in Turkish: Trepanasyon
trepan in Chinese: 頭部穿孔
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