Pectus excavatum (PE), often called “funnel chest” or “sunken chest,” is a common congenital chest wall deformity resulting in an inward depression of the sternum and rib cage. This structural anomaly has a direct relationship with the internal mechanics of the chest, leading to questions about its impact on pulmonary and cardiac function. The core concern for many patients is whether this deformity restricts the body’s ability to breathe and perform physical activity, though severity varies widely.
What Pectus Excavatum Is
Pectus excavatum (PE) is a structural malformation of the anterior thoracic wall characterized by an abnormal shape of the sternum and connected costal cartilages. The condition is caused by the excessive growth of the connective tissue joining the ribs to the breastbone, which pulls the sternum inward, creating a depression that can be symmetric or asymmetric. The deformity is present at birth but often becomes more noticeable and can worsen during periods of rapid growth, such as puberty. For some, the condition is mild and primarily a cosmetic concern. In more severe cases, the depth of the indentation can physically impinge upon the space intended for the organs inside the chest. The structural issue is fundamentally one of skeletal misalignment, rather than a problem with the lungs or heart tissue itself.
The Mechanism of Respiratory Impairment
The primary way pectus excavatum affects breathing is by physically reducing the internal volume of the chest cavity, a phenomenon that contributes to a restrictive lung pattern. The depressed sternum pushes into the mediastinum, the space containing the heart and major blood vessels. This reduces the available space for the lungs to fully expand, limiting maximum lung capacity and tidal volume, making it difficult to take a full, deep breath, especially during intense physical effort.
The inward curvature of the chest wall also mechanically hinders the natural bellows action of the rib cage during inhalation. A normal chest expands outward and upward to create the suction needed to draw air into the lungs, but the depressed portion of a PE chest may not move efficiently. This reduced chest wall motion means the patient must rely more heavily on the diaphragm, contributing to increased effort and fatigue during respiration.
Furthermore, the sternal depression can cause the heart to be displaced and sometimes rotated within the chest. This crowding of the mediastinum can indirectly affect lung capacity. The overall consequence is a reduction in pulmonary reserve, which is the ability to breathe effectively under stress.
Assessing Severity and Common Symptoms
The clinical impact of pectus excavatum is evaluated using objective measures, most notably the Haller Index (HI), which quantifies the severity of the depression. The Haller Index is calculated from a cross-sectional computed tomography (CT) scan as the ratio of the chest’s horizontal width to the shortest distance between the sternum and the spine. A normal HI value is 2.5 or less, and a measurement above 3.25 is considered an indication of a severe deformity.
The severity of the Haller Index correlates directly with the likelihood of functional impairment. Patients with an HI of 7, for example, are four times more likely to exhibit a restrictive pulmonary pattern than those with an HI of 4. This physical limitation manifests in a range of common symptoms, with the most frequent complaint being exercise intolerance. Patients often report shortness of breath, or dyspnea, particularly when engaging in rigorous physical activity.
Other common physical symptoms include chronic fatigue and chest pain, which can be musculoskeletal or related to the heart’s proximity to the compressed sternum. In severe cases, the displacement of the heart can lead to palpitations or an irregular heartbeat, further compounding the physical limitations.
Surgical and Non-Surgical Interventions
When pectus excavatum causes significant cardiopulmonary impairment, a range of interventions are available to restore normal thoracic volume and function. The most common surgical approach is the minimally invasive Nuss procedure, which involves inserting a curved metal bar beneath the sternum to push it outward. This bar is typically left in place for two to three years to allow the chest wall to remodel before it is removed. The Nuss procedure is generally favored for younger patients, as their costal cartilage is more pliable.
A traditional open-chest procedure, known as the Ravitch technique, is an alternative used for more complex cases, such as those with significant asymmetry or for older patients with a more rigid chest wall. This procedure involves making a longer incision, removing the deformed costal cartilage, and repositioning the sternum.
For less severe cases, or for patients who prefer to avoid surgery, non-surgical options like the Vacuum Bell device are available. This device is a suction cup applied to the chest that uses negative pressure to temporarily lift the sunken sternum. Regular use of the Vacuum Bell can gradually correct the deformity over several months.