Corneal graft Health Dictionary

See BONE TRANSPLANT.... bone graft

The term applied to a piece of tissue removed from one person or animal and implanted in another, or the same, individual in order to remedy some defect. Skin grafts are commonly used, and arti?cial skin for grafting has recently been developed. Bone grafts are also used to replace bone which has been lost by disease: for example, a portion of rib is sometimes removed in order to furnish support for a spine weakened by disease, after removal of the damaged bone. Also, the bone of young animals is used to a?ord additional growth and strength to a limb-bone which it has been necessary to remove in part on account of disease or injury. Research is also underway on arti?cal bone. Vein grafts are used to replace stretches of arteries which have become blocked, particularly in the heart and lower limbs. The veins most commonly used for this purpose are the saphenous veins of the individual in question, provided they are healthy. An alternative is specially treated umbilical vein. (See SKINGRAFTING.)

When a replacement organ, such as kidney, heart or liver, is ‘grafted’ into someone’s body, it called a ‘transplant’ (see TRANSPLANTATION).... graft

See: EYES, INFECTION. ... corneal ulcer

A complication of a bone marrow transplant in which immune system cells in the transplanted marrow attack the recipient’s tissues. Graft-versus-host (GVH) disease may occur soon after transplantation or appear some months later. The first sign is usually a skin rash. This may be followed by diarrhoea, abdominal pain, jaundice, inflammation of the eyes and mouth, and breathlessness.

GVH disease can usually be prevented by administration of immunosuppressant drugs. If the disease develops, it can be treated with corticosteroid drugs and immunosuppressant drugs such as ciclosporin In some cases, however, it can be difficult to control.... graft-versus-host disease

A technique used to repair areas of lost or damaged skin that are too large to heal naturally, that are slow

to heal, or that would leave tethering or unsightly scars. A skin graft is often used in the treatment of burns or sometimes for nonhealing ulcers. A piece of healthy skin is detached from one part of the body and transferred to the affected area. New skin cells grow from the graft and cover the damaged area. In a meshed graft, donor skin is removed and made into a mesh by cutting. The mesh is stretched to fit the recipient site; new skin cells grow to fill the spaces in the mesh. In a pinch graft, multiple small areas of skin are pinched up and removed from the donor site. Placed on the recipient site, they gradually expand to form a new sheet of healthy skin. (See also skin flap.)... skin graft

Instinctive closing of the eyelids when the surface of the cornea (see EYE) is lightly touched with a ?ne hair.... corneal reflex

When coronary arteries, narrowed by disease, cannot supply the heart muscle with su?cient blood, the cardiac circulation may be improved by grafting a section of vein from the leg to bypass the obstruction. Around 10,000 people in the United Kingdom have this operation annually and the results are usually good. It is a major procedure that lasts several hours and requires the heart to be stopped temporarily, with blood circulation and oxygenation taken over by a HEART-LUNG MACHINE.... coronary artery vein bypass grafting (cavbg)

A condition that is a common complication of BONE MARROW transplant (see TRANSPLANTATION). It results from certain LYMPHOCYTES in the transplanted marrow attacking the transplant recipient’s tissues, which they identify as ‘foreign’. GVHD may appear soon after a transplant or develop several months later. The condition, which is fatal in about a third of victims, may be prevented by immunosuppressant drugs such as ciclosporin.... graft versus host disease (gvhd)

An operation in which large breaches of SKIN surface due to wounding, burns or ulceration are closed by TRANSPLANTATION of skin from other parts. There are three methods by which this is done. Most frequently the epidermis only is transplanted, using a method introduced by Reverdin and by Thiersch, and known by their names. For this purpose, a broad strip of epidermis is shaved o? the thigh or upper arm, after the part has been carefully sterilised, and is transferred bodily to the raw or ulcerated surface, or is cut into smaller strips and laid upon it. A second method is for small pieces of the skin in its whole thickness to be removed from the arm and thigh, or even from other people, and then implanted and bound upon the raw surface. (This method has the disadvantage that the true skin must contract at the spot from which the graft is taken, leaving an unsightly scar.) When very large areas require to be covered, a third method is commonly used. A large ?ap of skin, amply su?cient to cover the gap, is raised from a neighbouring or distant part of the body, in such a way that it remains attached along one margin, so that blood vessels can still enter and nourish it. It is then turned so as to cover the gap; or, if it be situated on a distant part, the two parts are brought together and ?xed in this position until the ?ap grows ?rmly to its new bed. The old connection of the ?ap is then severed, leaving it growing in its new place.

Researchers are having success in growing human skin in the laboratory for grafting on to people who have been badly burned and have insu?cient intact skin surface to provide an autologous graft (one provided by the recipient of the graft). Other techniques being researched are the use of specially treated shark skin and the production of arti?cial skin.... skin-grafting

The term given to a method of SKIN-GRAFTING (see also GRAFT) in which strips of skin are shaved from a normal area and placed on a burned, injured or scarred area to be grafted.... thiersch’s graft

A scratch or defect in the epithelium (outer layer) of the cornea caused by a small, sharp particle in the eye (see eye, foreign body in) or by an injury. Corneal abrasions usually heal quickly but may cause severe pain and photophobia. Treatment includes covering the eye with a patch, analgesic drugs to relieve pain, and, if the eye muscles go into spasm, eyedrops containing cycloplegic drugs (which paralyse the ciliary muscle, preventing accommodation). Antibiotic eyedrops are usually

given to prevent bacterial infection, which can lead to a corneal ulcer.... corneal abrasion

See corneal graft.... corneal transplant

a white or greyish line in the periphery of the cornea, concentric with but separated from the edge by a clear zone. It begins above and below but may become a continuous ring. It consists of an infiltration of fatty material and is common in the elderly (arcus senilis). When it occurs in younger people (arcus juvenilis) it may indicate *hyperlipidaemia. It does not affect vision.... corneal arcus

The process of transplanting healthy tissue from one part of the body to another (autografting), from one person to another (allografting), or from an animal to a person (xenografting).

Grafting is used to repair or replace diseased, damaged, or defective tissues or organs. The most common operations of this type are skin graft, bone graft, bone marrow transplant, corneal graft, kidney transplant, heart transplant, liver transplant, heart–lung transplant, heartvalve surgery, and microsurgery on blood vessels and nerves.

With autografting, the grafted tissue is usually assimilated well into the surrounding tissue at the new site.

The general risks of tissue rejection following other forms of grafting are discussed in transplant surgery.... grafting

reflex blinking of both eyes normally elicited by lightly touching the cornea of one eye. This reflex is lost in deep coma, during general anaesthesia, and in death; it is therefore one of the tests used to confirm brainstem death.... corneal reflex

a ring designed to be inserted into the peripheral tissue of the cornea in order to alter the curvature of the corneal surface. It is undergoing trials to assess its ability to correct errors of refraction. In myopia (short-sightedness), for example, the ring would be required to stretch the corneal tissue peripherally and thus flatten the central corneal curvature in order to correct the myopia.... corneal ring

(videokeratography) an imaging technique used to study the shape and refractive power of the cornea in detail. An image projected onto the cornea is analysed by a computer to produce a representation of the shape and refractive power of the corneal surface. Corneal topography has an important role in the management of corneal disease and refractive surgery.... corneal topography

(CABG) *coronary revascularization in which a segment of a coronary artery narrowed by atheroma is bypassed by an *autologous section of healthy saphenous vein or internal mammary artery at *thoracotomy. The improved blood flow resulting from one or more such grafts relieves *angina pectoris and reduces the risk of *myocardial infarction. Recently developed techniques of *minimally invasive surgery have enabled the operation to be performed without the need for thoracotomy.... coronary artery bypass graft

(SSG, Thiersch’s graft) a type of skin graft in which thin partial thicknesses of skin are used to cover and heal a wound. They are removed from one site on the body, cut into narrow strips or sheets, and placed onto the wound area to be healed.... split-skin graft

see split-skin graft. [K. Thiersch (1822–95), German surgeon]... thiersch’s graft