The pectus carinatum (carina thorax) as well as other rare deformities of the front part of the thorax are linked to an enlargement of certain costal cartilages. Of varying severity, these deformities are generally without impact on health, but their aesthetic and psychological repercussions justify medical follow-up from childhood and the implementation of corrective orthopedic or surgical methods.

Definition

The pectus carinatum (carina thorax) is an infrequent deformation of the front part of the thorax: the sternum is thrown forward, the rib cage being bulging like the hull of a ship. The appearance is therefore opposite to that of the most common thoracic deformity, called pectus excavatum (funnel thorax), which corresponds to a hollow chest with a sunken breastbone.

People with pectus arcuatum have a mixed deformity in which the upper part of the sternum is prominent (pectus carinatum-type anomaly). The protrusion of the adjacent costal cartilages forms an arc which delimits a sternal “basin” in the underlying part (anomaly of the pectus excavatum type).

There are other mixed forms of anterior chest wall malformations, more or less complex and rare. Some are asymmetrical, the abnormalities being more marked on one side of the body than on the other.

The impact is above all aesthetic and psychological. In the most severe forms, cardio-respiratory disorders can develop.

Causes

Thoracic deformities are linked to an excess of development of costal cartilages in certain regions of the ribs, their enlargement leading to displacement of the sternum. Connective tissue abnormalities are sometimes associated. Genetic factors are believed to be involved but have not yet been identified.

Diagnostic

Careful examination of the thoracic deformity is sufficient to make a clinical diagnosis in children or adolescents. Rarely detected at birth, a keeled thorax becomes more visible as early as 3 or 4 years old and can no longer be ignored around puberty, when the rapid growth results in a very pronounced protrusion of the sternum.

A chest CT scan can be done in mixed and complex forms of rib cage deformities.

The people concerned

According to a 2013 American study (1), 0.6% to 0.7% of children aged 7 to 14 present with pectus carinatum, boys being four times more affected than girls.

The pectus carinatum would represent 10 to 15% of the thoracic deformities in France, and the pectus arcuatum of 1 to 5% according to the sources. Other forms of thoracic deformity are even rarer.

Risk factors

In 25% of cases, pectus carinatum is part of a family history of thoracic deformities.

It can appear in isolation but is quite frequently associated with other musculoskeletal disorders such as scoliosis or with syndromes such as Marfan syndrome or Noonan syndrome. 

Thoracic deformities

In many cases, deformities of the chest wall are the only manifestation of the disease. Most often, they appear and gradually worsen during childhood, peaking at puberty. The psycho-social impact of aesthetic damage can be considerable in adolescents in the process of constructing their identity.

Respiratory problems

A lack of endurance and breathing difficulties during exercise are quite common, the pectus carinatum preventing the complete exhalation of air and limiting gas exchange. Some people have asthma or have recurrent respiratory infections.

And more rarely:

• rapid heartbeat,
• tired,
• pains.

Orthopedic treatment

In children, the thorax is still elastic and can be reshaped by wearing an external compression device, implemented under medical supervision for at least 6 months.

The very restrictive rigid corsets of the past are increasingly being replaced by lighter dynamic compression devices, such as harnesses or bras. These devices exert a constant pressure on the protrusion of the sternum, adjusted by pressure sensors.

The aesthetic improvement is most often convincing and lasting, except for the most severe deformities.

Surgical treatment

In more severe forms and in adolescents over the age of puberty, surgical treatment remains the standard treatment. It is offered to adults or adolescents who have completed their growth spurt in order to avoid the risk of recurrence.

Operative procedures are less cumbersome than in the past and minimally invasive surgery is sometimes possible. Postoperative complications are rare, and results generally good.

The technique called simplified sternochondroplasty (or Ravitch technique) is the most common. It is based on the removal of abnormal cartilages, which may be associated with a partial section of the sternum. In mixed deformities, a titanium splint is sometimes implanted to promote repositioning of the sternum. A second operation will be necessary to remove it after 6 months.

Physical exercise

Strength training is not in itself a treatment, but the development of the pectoral muscles allows aesthetic improvement. Exercises that promote good posture and posture should be encouraged.