(lă-seg′) [Ernest C. Lasègue, Fr. physician, 1816–1883] In lumbar disk disease, pain that radiates into the leg after the hips and knees are flexed and the knee is extended. The test is suggestive of lumbar disc disease. It is usually performed with the patient supine or seated. Its diagnostic accuracy is best when pain occurs at less than 40° of flexion.
(lā′zĕr) [Acronym forlight amplification by stimulated emission of radiation] A device that emits intense heat and power on small target by converting various frequencies of light into a unified beam of a single frequency or wavelength. Lasers can influence cellular chemistry (the photochemical effects) and damage tissues by generating heat (such as producing coagulation, the photothermal effects). They can drill into, cavitate, or explode tissues (photomechanical effects) and can ablate tissues after transforming them into plasma. Lasers can also be used diagnostically (as by illuminating cells or tissues, as in fluorescence). They have many applications in laboratories and in surgical procedures. In ophthalmology, they are used to treat cataracts, diabetic retinopathy, macular degeneration, and retinal detachment; in cardiology, to vaporize arterial obstructions; in dermatology, to obliterate blood vessels and to remove warts, skin cancers, nevi, excess tissue, and tattoos; in gynecology, to remove vulval lesions, including genital warts; in gastroenterology, to control bleeding in the gastrointestinal tract; and in oral surgery and dentistry, to remove tumors. Many kinds of lasers are used depending upon the wavelength and power required, including argon, carbon dioxide, copper vapor, dye, excimer, helium-neon, ion, krypton, neodymium:yttrium-aluminum garnet, and ruby lasers.
Laser safety precautions must be observed: Warning signs should be posted indicating that a laser is being used; equipment must be checked before the procedure; conventional endotracheal tubes must be wrapped with aluminum foil tape (flexible metallic endotracheal tubes insulated with silicone may be used); skin preparation solution should not contain combustible agents; and towels draped around the site must be kept wet. The laser equipment must be moved carefully to avoid jarring the mirrors out of alignment. Alcohol-based skin preparations should not be used.
argon l. A gas-produced laser (in the blue and green visible light spectrum) with a wavelength 488 nm to 633 nm, used in the coagulation of tissue and in photodynamic therapy. Argon lasers are used to treat skin lesions, bleeding ulcers, hemangiomas, periodontal disease, glaucoma, and retinal diseases.
carbon dioxide l. ABBR: CO2 laser. A gas-produced colorless laser with a wavelength of 10,600 nm (infrared), used in dermatological surgeries to remove scars, wrinkles, and solar skin damage. Carbon dioxide lasers can also be used as a scalpel in stereotactic neurosurgeries and gynecological surgeries.
PATIENT CARE: Laser precautions must be observed. The staff support the patient by answering questions and explaining the need for eye covering during the procedure. ...