Pectus Excavatum, or sunken chest, is a structural deformity of the front chest wall where the breastbone and connecting ribs grow abnormally inward. This creates a distinct caved-in appearance in the center of the chest. It is the most common congenital abnormality of the chest wall, affecting approximately 1 in 400 to 1,000 newborns. While present from birth, the deformity often becomes more noticeable and can worsen significantly during periods of rapid growth, especially adolescence.
Defining Pectus Excavatum and Its Appearance
Pectus Excavatum involves the inward depression of the sternum (breastbone) and typically affects four to five connecting ribs on each side. The severity of the indentation ranges from a slight dip to a deep depression. The resulting concavity can be cup-shaped, involving only the lower end of the sternum, or a broader depression involving the upper costal cartilages.
The deformity’s appearance can be symmetrical (the sternum caving straight back) or asymmetrical (where the sternum is rotated to one side). The lower ribs often protrude outward, known as flared ribs, which emphasizes the sunken appearance. The condition is classified as mild, moderate, or severe based on the depth of the depression, correlating to the degree of potential internal compression.
Underlying Causes and Risk Factors
The mechanism behind this deformity is the excessive, irregular growth of the costal cartilage, the flexible tissue connecting the ribs to the sternum. This overgrowth creates outward pressure, forcing the breastbone inward. Although the exact trigger for this abnormal growth is not fully understood, a genetic component is suspected.
The condition often runs in families; approximately 40% of affected individuals have family members with the same deformity, suggesting an inherited predisposition. Pectus Excavatum is associated with certain connective tissue disorders, which affect the body’s structural proteins. Specific conditions include Marfan syndrome and Ehlers-Danlos syndrome.
Physical and Functional Impact on the Body
In moderate to severe cases, the inward depression of the sternum reduces space within the chest cavity, leading to functional consequences for the heart and lungs. The heart can become compressed or displaced, often rotating into the left side of the chest. This compression impairs the heart’s ability to fill with blood efficiently, particularly the right ventricle, which decreases stroke volume during physical activity.
Reduced cardiac efficiency manifests as symptoms such as a fast or pounding heart, shortness of breath, and loss of endurance or tiredness during exercise. The restricted space affects lung function, sometimes causing a restrictive pattern of breathing that diminishes total lung capacity. Chronic pain in the chest and back is common, often resulting from poor posture and muscle strain associated with concealing the deformity.
The condition’s visible nature leads to significant psychological effects, especially during adolescence when body image concerns are heightened. Individuals often experience self-consciousness, low self-esteem, and social anxiety, sometimes avoiding activities that require exposing the chest. To assess functional impact and severity, physicians use imaging like a computed tomography (CT) scan to calculate the Haller Index. This index measures the ratio between the internal transverse diameter of the chest and the shortest distance from the sternum to the spine; a ratio greater than 3.25 indicates a severe deformity and correlates with cardiopulmonary impairment.
Treatment Options for Correction
Treatment decisions depend on the severity of the deformity and the presence of functional or psychological symptoms. For mild cases without cardiopulmonary issues, non-surgical management is the first approach. This involves targeted physical therapy to improve posture and strengthen chest muscles, which may help mask the indentation.
Another non-surgical option is the vacuum bell device, a suction cup placed on the chest that creates a vacuum to gently pull the sternum outward over time. This device is used for younger patients with flexible chest walls, requiring consistent daily wear for a year or more for lasting correction. For moderate to severe cases with functional impairment, surgical correction is recommended.
The two main surgical procedures are the minimally invasive Nuss procedure and the modified Ravitch procedure. Both approaches aim to relieve pressure on the heart and lungs while correcting the chest wall’s appearance.
Nuss Procedure
The Nuss procedure involves placing a curved metal bar behind the sternum through small incisions. The bar is then flipped to push the breastbone into a normal position. It remains in place for two to three years before removal and is the most common technique for younger patients.
Ravitch Procedure
The Ravitch procedure is a traditional, open-chest technique where the deformed costal cartilage is surgically removed, and the sternum is repositioned.