- - amputation k. a broad-bladed k. used primarily for transecting large muscles during major amputations.- Beer k. a triangular k. with a sharp point and one sharp edge, formerly used for incision for cataract.- electrode k. a blade-shaped electrical instrument used to cut tissues by means of a high-frequency electrical current.- free-hand k. a manually operated k. or blade usually used to take split-thickness skin grafts; e.g., Blair-Brown k., Humby k..- gamma k. a minimally invasive radiosurgical system used in the treatment of benign and malignant intracranial neoplasms and arteriovenous malformations. SEE ALSO: radiosurgery.As a preliminary to use of the gamma k., the lesion to be ablated is precisely located by imaging techniques such as MRI, CT, PET, and angiography. Beams of gamma rays from 200 cobalt-60 sources are then directed by a computer so that they converge on the lesion. A series of exposures are made during a period of about 1 hour. Lesions larger than about 3 cm cannot be treated. The mechanism is bulky and costly, but the procedure has shown a success rate of about 85% in the treatment of arteriovenous malformations and 50–95% for neoplasms. Besides avoiding the risks and complications of open surgery, the gamma k. permits treatment of lesions whose location prohibits any attempt at surgical removal. In addition, patient discomfort is minimal and most patients remain in the hospital for only 1 night; many return home, or even to work, on the day of treatment. The gamma k. is expected to prove useful in the treatment of other disorders, such as tumors of the eye and the pituitary gland, trigeminal neuralgia, epilepsy, parkinsonism, and other movement disorders.- hernia k. a slender bladed k., with short cutting edge, for dividing the constricting tissues at the mouth of the hernial sac. SYN: herniotome.- Liston knives long-bladed knives of various sizes used in amputations.
* * *1) any of various instruments used in surgery primarily to sever tissues: asa) a cutting instrument consisting of a sharp blade attached to a handleb) an instrument that cuts by means of an electric current2) SURGERY (3) usu. used in the phrase under the knife <went under the \knife yesterday> <was afraid of the \knife>
* * *(nīf) any of various types of cutting instruments.
Medical dictionary. 2011.