Norwood procedure
Encyclopedia
The Norwood Procedure is a surgery
performed on the heart
, the first successful use of the procedure was reported by Norwood and colleagues in 1981.
Cardiopulmonary bypass is required.
, certain types of mitral atresia, or other conditions that result in single ventricle circulation.
In these conditions, the most urgent problem is that the heart is unable to pump blood to the systemic circulation (i.e. to the body). The goal of the Norwood procedure is to connect the single ventricle to the systemic circulation. To accomplish this, blood flow to the lungs is disrupted, and therefore an alternative path must be created to supply the lungs.
This surgery is complex and may vary slightly depending on the diagnosis
and overall condition of the heart
.
The surgery on the heart can be divided into two main steps.
is separated from the left and right portions of the pulmonary artery and joined with the upper portion of the aorta
. Widening of the pulmonary artery
is often necessary, and may be accomplished by using the patient's existing biological tissue
, or appropriate animal tissue. This allows the blood
, a mixture of oxygenated
and deoxygenated, to be pumped to the body via the pulmonary valve
.
After this first step (switching the right ventricle in functional position of the absent left ventricle) children generally proceed down the path to a Fontan procedure
.
Surgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...
performed on the heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
, the first successful use of the procedure was reported by Norwood and colleagues in 1981.
Cardiopulmonary bypass is required.
Indications
This procedure is most often performed to treat Hypoplastic Left Heart SyndromeHypoplastic left heart syndrome
Hypoplastic left heart syndrome , is a rare congenital heart defect in which the left ventricle of the heart is severely underdeveloped.-Causes:...
, certain types of mitral atresia, or other conditions that result in single ventricle circulation.
In these conditions, the most urgent problem is that the heart is unable to pump blood to the systemic circulation (i.e. to the body). The goal of the Norwood procedure is to connect the single ventricle to the systemic circulation. To accomplish this, blood flow to the lungs is disrupted, and therefore an alternative path must be created to supply the lungs.
Process
Entry to the body cavity for the Norwood Procedure is gained by a vertical incision above the sternum. Separation of the sternum is necessary.This surgery is complex and may vary slightly depending on the diagnosis
Diagnosis
Diagnosis is the identification of the nature and cause of anything. Diagnosis is used in many different disciplines with variations in the use of logics, analytics, and experience to determine the cause and effect relationships...
and overall condition of the heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
.
The surgery on the heart can be divided into two main steps.
Providing systemic circulation
The main pulmonary arteryPulmonary artery
The pulmonary arteries carry deoxygenated blood from the heart to the lungs. They are the only arteries that carry deoxygenated blood....
is separated from the left and right portions of the pulmonary artery and joined with the upper portion of the aorta
Aorta
The aorta is the largest artery in the body, originating from the left ventricle of the heart and extending down to the abdomen, where it branches off into two smaller arteries...
. Widening of the pulmonary artery
Pulmonary artery
The pulmonary arteries carry deoxygenated blood from the heart to the lungs. They are the only arteries that carry deoxygenated blood....
is often necessary, and may be accomplished by using the patient's existing biological tissue
Biological tissue
Tissue is a cellular organizational level intermediate between cells and a complete organism. A tissue is an ensemble of cells, not necessarily identical, but from the same origin, that together carry out a specific function. These are called tissues because of their identical functioning...
, or appropriate animal tissue. This allows the blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
, a mixture of oxygenated
Dioxygen complex
Dioxygen complexes are coordination compounds that contain O2 as a ligand. The study of these compounds is inspired by oxygen-carrying proteins such as myoglobin, hemoglobin, hemerythrin, and hemocyanin. Several transition metals form complexes with O2, and many of these complexes form reversibly...
and deoxygenated, to be pumped to the body via the pulmonary valve
Pulmonary valve
The pulmonary valve is the semilunar valve of the heart that lies between the right ventricle and the pulmonary artery and has three cusps. Similar to the aortic valve, the pulmonary valve opens in ventricular systole, when the pressure in the right ventricle rises above the pressure in the...
.
Providing pulmonary circulation
Since the remainder of the pulmonary artery is now disconnected from the heart, one of a few techniques must be used to supply blood to the lungs:- With a modified Blalock-Taussig ShuntBlalock-Taussig shuntThe Blalock–Taussig shunt is a surgical procedure to give palliation to cyanotic heart defects which are common causes of blue baby syndrome...
, a Gore-TexGore-TexGore-Tex is a waterproof/breathable fabric, and a registered trademark of W. L. Gore and Associates. It was co-invented by Wilbert L. Gore, Rowena Taylor, and Gore's son, Robert W. Gore. Robert Gore was granted on April 27, 1976, for a porous form of polytetrafluoroethylene with a...
conduit (a kind of plastic tubing) is used to connect the subclavian arterySubclavian arteryIn human anatomy, the subclavian arteries are two major arteries of the upper thorax , below the clavicle . They receive blood from the top of the aorta...
to the pulmonary artery. In this case, blood comes from the single ventricle, through the pulmonary valve, the reconstructed aorta, the subclavian artery, and the conduit, to the lungs. There are variations on this procedure where the origin of the shunt is elsewhere in the systemic circulation (e.g. from the aorta itself) rather than the subclavian artery. - With a Sano shuntSano shuntA Sano shunt is a shunt from the right ventricle to the pulmonary circulation.In contrast to a Blalock–Taussig shunt, circulation is primarily in systole.It is sometimes used as the first step in a Norwood procedure....
, a hole is made in the wall of the single ventricle, and a Gore-Tex conduit is used to connect the ventricle to the pulmonary artery. The key difference here is that the blood flow is more pulsatile than with the Blalock-Taussig version.
After this first step (switching the right ventricle in functional position of the absent left ventricle) children generally proceed down the path to a Fontan procedure
Fontan procedure
The Fontan procedure, or Fontan/Kreutzer procedure, is a palliative surgical procedure used in children with complex congenital heart defects. It involves diverting the venous blood from the right atrium to the pulmonary arteries without passing through the morphologic pulmonary ventricle...
.
External links
- http://heart.healthcentersonline.com/pediatricheartsurgery/norwoodprocedure.cfm, Health Centers Online
- University of Michigan - HLHS - Stage 1 Norwood Procedure http://www.med.umich.edu/cvc/mchc/parhyp1.htm