Pectus excavatum (PE) is the most common deformity of the chest wall, characterized by the abnormal growth of rib cartilage that causes the sternum (breastbone) to sink inward. This structural anomaly gives the chest a characteristic sunken or funnel-shaped appearance. A frequent concern for those managing the condition is whether this depression will deepen over time. Understanding the typical pattern of PE progression is important for effective long-term management.
The Progression of Pectus Excavatum
The progression of pectus excavatum is closely tied to the body’s natural periods of skeletal growth. The most substantial worsening of the chest wall depression typically takes place during the rapid growth phase of adolescence, often between the ages of 10 and 14 years. This accelerated development can transform a mild deformity into a much more noticeable or severe one in a relatively short period.
The underlying cause of this progression during puberty is an overgrowth of the costal cartilage, which connects the ribs to the sternum. As the cartilage grows faster than the surrounding bone structure, it pushes the sternum inward, exaggerating the indentation. This period of rapid change is often when patients first notice the condition or experience a sudden deepening of the depression.
Once an individual reaches skeletal maturity, typically in the late teens or early twenties, the progression of the physical deformity largely stabilizes. At this point, the cartilage and bone growth plates have closed, and the chest wall structure becomes more rigid. The actual depth of the skeletal deformity is unlikely to increase significantly in adulthood.
Any perceived worsening in adults is often related to changes in body composition or posture rather than structural changes in the ribcage. Poor posture, such as chronic slouching, or the accumulation of abdominal fat can visually emphasize the existing depression. While the bony structure generally stops changing, lifestyle factors can influence the appearance and overall physical presentation.
Measuring Severity
To objectively assess the degree of chest wall depression, clinicians rely on the standardized Haller Index (HI). This quantitative measure determines the severity of the pectus excavatum deformity. The calculation is derived from imaging, typically a Computed Tomography (CT) scan, taken at the level of the deepest sternal depression.
The Haller Index is a ratio comparing the maximal transverse diameter of the internal chest cavity to the minimal anteroposterior distance between the sternum and the spine. For an individual without the condition, the HI generally falls around 2.5. A higher numerical value indicates a greater degree of inward displacement of the sternum and a more severe deformity.
An HI greater than 3.25 is often used as a benchmark to classify the condition as severe and is frequently a threshold for considering therapeutic intervention. Quantifying the deformity using this index is important because external appearance does not always reflect the true internal severity. Accurate measurement helps determine the potential for physiological impact and guides management decisions.
Physical and Physiological Effects of Increased Severity
When the pectus excavatum deformity progresses significantly, the sunken sternum begins to exert pressure on the organs within the thoracic cavity, particularly the heart and lungs. A high Haller Index often correlates with an increased likelihood of experiencing these physiological effects. The mechanical compression caused by the inward-caving chest wall can limit the space available for these organs to function optimally.
The impact on the heart is often related to displacement and restricted filling, especially during physical activity. Severe deformities can push the heart to the left side of the chest. The right side of the heart may experience direct compression, impeding its ability to expand fully. This compression can lead to reduced cardiac output, meaning the heart struggles to pump sufficient blood during periods of exertion.
The effect on the lungs primarily involves a restrictive pattern of breathing, where the chest cannot fully expand. The depressed sternum restricts the normal movement of the chest wall during inhalation, which can lead to a decrease in lung volumes, such as forced vital capacity (FVC). This mechanical restriction results in symptoms like shortness of breath, reduced stamina, and fatigue, particularly as physical demands increase.
An HI greater than 3.6 has been associated with measurable pulmonary dysfunction, indicating a restriction in lung function. The degree of physiologic impairment is linked to the severity of the depression, with severe cases having a higher incidence of cardiopulmonary limitations. In rare, extremely severe cases, symptoms such as chronic respiratory acidosis or recurrent syncope due to compression of the inferior vena cava have been documented.
Monitoring and Non-Surgical Interventions
Since the most significant progression occurs during growth spurts, regular clinical monitoring is a primary strategy. Physicians often recommend frequent check-ups, especially after the age of ten, to track the deformity’s depth and symmetry. Early and consistent monitoring allows for timely assessment of the condition’s severity and potential for symptom development.
Non-surgical interventions focus on managing symptoms, improving posture, and potentially mitigating the severity of the depression while the chest wall is still flexible. Physical therapy programs are commonly utilized to address associated issues. Strengthening the back and chest muscles can improve the overall presentation and potentially reduce the visible prominence of the indentation.
Another non-invasive option is the Vacuum Bell device, a suction cup placed on the chest that creates a vacuum to gently pull the depressed sternum forward. This device relies on the flexibility of the chest wall and is considered most effective when treatment begins before the patient reaches full skeletal maturity. Consistent use over an extended period aims to gradually remodel the chest wall structure.
The success of the Vacuum Bell depends on the patient’s compliance and motivation, often requiring daily application for several hours over many months. Combining the use of the device with a structured physical therapy program can lead to better outcomes in terms of correction and improved posture.