Pectus Deformities

Abstract

Chest wall malformations can be present at birth or become evident in infancy, childhood or early adolescence. Congenital chest wall deformities fall into two groups: those with overgrowth of the rib cartilages causing a depression or protrusion of the sternum, and those with varying degrees of aplasia or dysplasia. The most common chest wall malformations are the depression or protrusion abnormalities called pectus excavatum and pectus carinatum. The excavatum defect constitutes about 88% of the deformities while the carinatum deformity makes up another 5%.

Appendices

Summary Points

Pectus excavatum is the most common (90%) congenital chest wall deformity, occurring in between 1 and 3 in 1,000 individuals.

In addition to poor body image, many patients with pectus excavatum describe symptoms of poor exercise tolerance and shortness of breath, presumably due to compression or displacement of the heart and lungs.

Pectus excavatum mainly involves the lower portion of the sternum below the insertion of the second costal cartilage and can be symmetric or asymmetric.

The Haller index (transverse diameter of chest divided by the antero-posterior diameter at the deepest portion of defect) is a measure of severity of pectus excavatum, >3.25 being a typical indication for surgical correction.

Patients with pectus excavatum should be screened for Marfan’s disease, scoliosis, and congenital heart disease.

The minimally invasive approach to the correction of pectus excavatum has been proven to be safe, effective, and durable.

Pectus carinatum (5% of pectus deformities) is corrected using an external brace that gradually reshapes the sternum posteriorly.

Editor’s Comment

The “Nuss” procedure has revolutionized the treatment of pectus excavatum. It is very effective, has a low complication rate, and is associated with minimal external scarring when compared to the traditional “Ravitch” operation. The principal drawback is extreme pain, which is usually effectively managed in the immediate postoperative period with a thoracic epidural catheter, and for the first 2–3 weeks with narcotic analgesics. Narcotic addiction is a significant concern but should be rare with ethical and appropriate pain management techniques and conversion of non-narcotic analgesics as soon as possible after the operation.

Whether pectus excavatum produces measurable deficits in cardiac or respiratory function is controversial. Although many believe it is purely a cosmetic defect, patients frequently describe significant symptoms before surgery and many report considerable (albeit subjective) improvement in their stamina and comfort after the operation. Especially in active teenagers, flipping of the bar remains a constant worry but is thankfully rare, especially with the current widespread use of bar stabilizers.

The Ravitch repair done well is elegant and effective in its own right, but should only be offered when there are contraindications to the minimally invasive approach. Rather than remove all the costal cartilages, Dr. Haller described a technique whereby some of the cartilages are bisected at an angle (anteromedial to posterolateral) and the medial half is brought anterior to the lateral half, thus helping to push the sternum anteriorly. They should be stitched in this position to avoid postoperative slippage. A bar is not always necessary, but recommended for severe defects especially in older teenagers and adults.

In many cases, pectus carinatum is even more of a cosmetic concern than pectus excavatum. The operations described for correction of this defect are more invasive and perhaps less effective than those available for pectus excavatum. The external bracing technique, in which external pressure is applied to the sternum, appears to be very effective; however, compliance remains a significant hurdle.

Differential Diagnosis

• Pectus excavatum

• Pectus carinatum

• Mixed pectus deformity

Diagnostic Studies

• Thoracic CT scan with calculation of Haller index

• Pulmonary function testing

• EEG/echocardiogram, where appropriate

Parenteral Preparation

• The minimally invasive approach to correction of pectus excavatum is painful but we have a plan to make your child comfortable, including a thoracic epidural catheter for the immediate postoperative period.

• The stabilizer bar(s) passes between the sternum and the heart, but we will use thoracoscopy to help avoid serious injuries.

• The bar(s) will need to be removed in a second procedure 2–3 years after the initial operation.

Preoperative Preparation

• Medical imaging

• Preoperative photographs

• Complete blood count

• Type and crossmatch

Technical Points

• Patient is positioned supine with the arms abducted at the shoulder (at no more than 90º to avoid a brachial plexus nerve injury).

• The bar should be placed at the deepest point of the defect, no lower than the distal sternum.

• The incisions are made laterally on a line that goes through the deepest point of the defect.

• The bar length should be 1 in. less than the distance between the axillary lines measured with tape.

• The bar should be bent into the shape of a semicircle with a 2-cm flat section at the apex, creating a slight over-correction.

• For older children with severe defects, two (or even three) bars might be necessary.

• The chest is entered under thoracoscopic guidance at the top of the pectus ridge, never lateral to the ridge, so that the load is borne by the ribs, not the intercostal muscles.

• Stabilizer bars are useful to prevent flipping of the bar.

• Bars are left in place for 3 years.

• The open (“Ravitch”) technique involves removal of the costal cartilages while preserving the perichondrium, a transverse anterior osteotomy of the sternum, and, sometimes, a straight support bar.