Deformities of the Chest Wall

Chest wall deformities are structural abnormalities in the shape, symmetry, or integrity of the thoracic cage, involving the ribs, sternum, or spine. These deformities can be congenital or acquired and may have significant implications for respiratory function, cardiovascular health, and overall physical appearance.

Types of Chest Wall Deformities:

1. Pectus Excavatum (Funnel Chest)

• The most common congenital chest wall deformity, characterized by a sunken appearance of the anterior chest due to posterior displacement of the sternum and costal cartilages.
• Pathophysiology: Results from abnormal growth of the costal cartilages, leading to inward compression of the sternum. The degree of displacement can affect cardiac and pulmonary function due to reduced thoracic volume.
• Clinical Presentation: May include exercise intolerance, chest pain, palpitations, dyspnea, and psychological distress related to body image. Severe cases can cause displacement of the heart (usually leftward) and reduced lung expansion.
• Complications: Includes restrictive lung disease, mitral valve prolapse, and, rarely, arrhythmias due to mechanical compression.

2. Pectus Carinatum (Pigeon Chest)

• Characterized by an outward protrusion of the sternum and adjacent ribs, giving the chest a keeled or bird-like appearance.
• Pathophysiology: Usually caused by overgrowth of the costal cartilages. Can be symmetric or asymmetric and may develop or worsen during periods of rapid growth, such as adolescence.
• Clinical Presentation: Often asymptomatic, but some patients may report dyspnea on exertion, chest pain, or exercise intolerance. Cosmetic concerns are common, leading to psychological distress.
• Complications: Rarely associated with significant cardiorespiratory issues but may contribute to scoliosis or restrictive lung disease in severe cases.

3. Poland Syndrome

• A rare congenital condition characterized by unilateral absence or underdevelopment of the pectoralis major muscle, with possible ipsilateral chest wall deformities, rib anomalies, and limb abnormalities (e.g., brachysyndactyly).
• Pathophysiology: Believed to result from disruption of blood supply to the subclavian artery during embryogenesis.
• Clinical Presentation: May range from mild asymmetry to severe chest wall deformity, often accompanied by upper limb defects such as webbing of the fingers (syndactyly).
• Complications: Can include functional limitations of the shoulder or arm, and psychological impact due to the visible deformity.

4. Jeune Syndrome (Asphyxiating Thoracic Dystrophy)

• A rare genetic disorder characterized by a narrow, small, bell-shaped thorax with shortened ribs, which restricts lung development and expansion.
• Pathophysiology: Caused by mutations affecting ciliary function, leading to defects in skeletal development.
• Clinical Presentation: Presents in infancy or early childhood with respiratory distress due to restrictive lung disease, recurrent respiratory infections, and failure to thrive. In severe cases, it may cause respiratory failure.
• Complications: Includes chronic respiratory insufficiency, recurrent infections, and potentially fatal respiratory failure.

5. Chest Wall Tumors

• Can be primary (originating from bone, cartilage, or soft tissue) or secondary (metastatic).
• Pathophysiology: Tumors such as chondrosarcoma, osteosarcoma, or metastatic lesions from breast or lung cancer can alter the structure and function of the chest wall.
• Clinical Presentation: May include localized pain, a palpable mass, and functional impairment related to respiratory mechanics. Malignant tumors often present with systemic symptoms such as weight loss or fever.
• Complications: Risk of pathologic fractures, respiratory compromise, and metastasis.

6. Scoliosis-Associated Chest Wall Deformities

• Involves lateral curvature of the spine with associated rotation, which can cause rib prominence or asymmetry in the chest wall.
• Pathophysiology: The rotational component of scoliosis causes one side of the ribcage to protrude posteriorly (rib hump), while the other side flattens or is depressed anteriorly.
• Clinical Presentation: May cause uneven shoulder height, back pain, and respiratory issues due to restrictive lung patterns in severe cases.
• Complications: Severe deformities can impair lung function, increase the risk of respiratory infections, and affect cardiovascular function.

Diagnosis:

1. Clinical Evaluation:
   • Comprehensive history and physical examination, noting the type and severity of deformity, associated symptoms, and any family history of congenital abnormalities.
2. Imaging:
   • Chest X-ray: Useful for assessing the bony structure of the thorax and identifying scoliosis or rib abnormalities.
   • CT Scan: Provides detailed visualization of the sternum, ribs, and underlying soft tissues; helps evaluate the degree of deformity and any cardiopulmonary compression.
   • MRI: Used in complex cases to assess soft tissue involvement or spinal abnormalities.
3. Pulmonary Function Tests (PFTs):
   • Assess the impact of the deformity on lung function, particularly in conditions like pectus excavatum or Jeune syndrome, where restrictive lung disease is common.
4. Echocardiography:
   • Recommended for evaluating cardiac displacement or compression in severe cases of pectus excavatum.

Management:

1. Conservative Management

• Bracing: Effective for mild to moderate cases of pectus carinatum, especially in children and adolescents. Braces apply external pressure to gradually reshape the chest wall.
• Physical Therapy and Respiratory Exercises: Beneficial in improving posture, respiratory mechanics, and chest wall mobility.
• Psychological Support: Counseling may be necessary to address body image concerns or anxiety related to physical appearance.

2. Surgical Management

• Nuss Procedure (for Pectus Excavatum):
  • A minimally invasive technique involving the insertion of a curved metal bar under the sternum to elevate it into a more normal position. The bar is typically left in place for 2-3 years before removal.
  • Indicated for severe deformities causing significant cardiopulmonary compromise or psychological distress.
• Ravitch Procedure (for Pectus Excavatum or Carinatum):
  • An open surgical approach that involves resecting abnormal costal cartilages and repositioning the sternum.
  • Usually reserved for complex or recurrent cases.
• Reconstructive Surgery (for Poland Syndrome or Chest Wall Tumors):
  • May involve muscle flap reconstruction, rib grafting, or prosthetic implants to improve chest wall integrity and symmetry.
• Thoracoplasty (for Severe Scoliosis or Chest Wall Tumors):
  • Surgical reshaping of the ribs to correct deformity and improve lung function.

3. Management of Jeune Syndrome

• Ventilatory Support: Early intervention with mechanical ventilation or non-invasive respiratory support may be required for infants with respiratory distress.
• Surgical Rib Expansion: May be performed to enlarge the thoracic cavity and improve lung function.

Complications of Treatment:

• Postoperative complications: Include infection, pneumothorax, bleeding, bar displacement (in Nuss procedure), and chronic pain.
• Recurrence: Deformities like pectus carinatum may recur if bracing or surgical techniques are not maintained for the recommended duration.
• Surgical Risks in High-Risk Patients: Those with comorbidities or severe deformities require careful preoperative evaluation and management.

Prognosis:

• Mild Deformities: Often have a good prognosis with conservative management.
• Severe Cases: Prognosis depends on the extent of cardiopulmonary involvement, underlying syndromic associations (e.g., Jeune syndrome), and timely intervention.
• Surgical Outcomes: Generally favorable, especially for procedures like the Nuss or Ravitch, with significant improvements in quality of life, respiratory function, and cosmetic appearance.