Pectus Excavatum and Pectus Carinatum

DEFINITION

Pectus excavatum is the most common chest wall deformity that involves a concave deflection of the sternum posteriorly, with a wide range of severity from slight depression to almost reaching the level of the vertebrae. This abnormality can be present at birth but more frequently becomes apparent during puberty when rapid growth occurs.
It occurs more frequently in males than females (3:1 ratio).
Indications for repair include symptomatic relief, improved appearance, or to alleviate psychosocial anxiety due to the defect.
Pectus carinatum is a congenital chest wall anomaly sometimes referred to as “pigeon chest,” less common than excavatum, which is associated with a convex deformity of the sternum, leading to protrusion of the chest wall.
Two general types are described: chondrogladiolar, which is symmetric protrusion of the body of the sternum and cartilage, and chondromanubrial, which is protrusion of the manubrium sternum with inward depression of the inferior portion. This generally presents during adolescence and has a male predominance.¹

PATIENT HISTORY AND PHYSICAL FINDINGS

As with any patient, the first approach is a thorough history. The time course of presentation is important to identify, as it can vary from infancy to adolescence.
- The progression of the deformity is important to note. For example, during puberty the deformity can rapidly become much more prominent.
- Symptoms associated with pectus excavatum (PE) are rare but can include dyspnea or exercise intolerance. However, the majority of patients will not report symptoms.
- Often, the presenting complaint is poor appearance due to the enlarging deformity at puberty.
- Clear documentation of dyspnea, exercise intolerance, or worsening dyspnea is important to facilitate insurance coverage.
- Family history regarding chest wall deformities should be obtained; there is a 25% rate of positive family history.
- Cardiopulmonary sequela has long been investigated; however, definitive results are still lacking. It has been shown that patients have normal spirometry preoperatively but can report subjective improvement in breathing postoperatively.
On physical exam, symmetry of the chest should be examined. Often, asymmetry can occur, most frequently favoring the right side. Calipers can be used to determine the depth and width of the deformity; however, computed tomography (CT) scan has become a more standardized way to categorize defects.
Chest wall inspection includes observing chest wall symmetry or asymmetry, as well as the type of deformity present.
Auscultation can reveal displaced cardiac sounds. Additionally, a systolic ejection murmur can sometime be appreciated due to the proximity of the chest wall to the pulmonary artery. Mitral regurgitation can also be present.
Examination of the rest of the body, looking for stigmata of Marfan syndrome including long digits or history of bruising. If present, a full evaluation for Marfan syndrome should be done.

IMAGING AND OTHER DIAGNOSIS STUDIES

Computed tomography of the chest has now become important for diagnosing severity of the PE. The Haller index is calculated from the axial images using the ratio of the transverse diameter from the inner ribs to the length of the greatest point on defect between the posterior sternum and anterior vertebrae. A ratio greater than 3.2 is considered a severe defect.²
Plain chest radiograph, posteroanterior (PA) and lateral views, has been described to calculate the Haller index as well and in some studies has been found to be equivalent for predicting severity.³ However, most patients will generally still have CT scan for evaluation.
Pulmonary function tests in patients with pectus excavatum have been shown to have 10% to 20% less of the expected lung volume on spirometry. Additionally, the forced expiratory volume has been shown to be less than 80% of the predicted value for patients of similar age without pectus abnormalities.⁴
Echocardiogram for cardiac evaluation is very important in this group of patients. There is a higher prevalence of cardiac abnormalities including right ventricular compression, mitral valve prolapse and arrhythmias. An echocardiogram is important to evaluate if cardiac structure is abnormal to allow for proper operative planning if identified.⁴

SURGICAL MANAGEMENT

Preoperative Planning

Pectus Excavatum

In general, it is preferred to time repair during the pubertal growth phase, usually from ages 10 to 15.⁵ This is because the rapid growth phase can worsen pectus and therefore cause a previously repaired defect to recur. However, for children with severe exercise intolerance, earlier repair can be considered.
Indications for operative correction include Haller index greater than 3.2, progression of severity of disease, pulmonary function tests (PFTs) demonstrating obstructive or restrictive lung patterns, or cardiac abnormalities such as displacement, arrhythmias, or murmurs.⁶
There are two different types of repair: open (or Ravitch procedure) and the minimally invasive procedure (Nuss). There are a few important considerations to make when deciding which approach is appropriate. In patients with severe asymmetry, the open approach is often favored. Additionally, in patients presenting with a failed Nuss procedure, the open procedure should be considered for the second repair. However, overall, the Nuss procedure tends to be the procedure of choice for consideration in lower postoperative pain as well as improved appearance from its minimally invasive nature.
If pursuing noninvasive repair with a Nuss bar, it is crucial to determine if the patient has allergies to metal, or a family history of metal allergy. If a family history is present, subsequent skin testing for metal allergy is necessary before proceeding. If an allergy is present, a titanium bar should be used instead of the standard stainless steel.
The bar length for the Nuss procedure should be 2.5 cm shorter than the distance from the right to left midaxillary line.⁷
General anesthesia should be achieved prior to beginning the operation, and a secure airway must be obtained at the beginning of the case.

Pectus Carinatum

In general, most children with pectus carinatum will not require surgery. For children that are younger and have not yet completed puberty, orthotic bracing regimens are attempted to mold the chest into the correct position. Up to 75% of patients will achieve significant or complete correction of the pectus carinatum deformity using bracing alone.⁸
The most common reason for incomplete or failed correction is patient noncompliance with bracing regimen. Noncompliance often results from failure to wear the brace often enough or in time periods long enough to correct the deformity.
If the defect fails to improve, surgical correction can then be pursued.