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About Pectus Excavatum

 

Pectus Excavatum is the most frequent congenital deformity of the thoracic cavity, since it represents almost 95% of cases. It is characterized by a depression of the sternum that gives a sunken appearance to the chest, also known as a funnel chest. The malformation is diagnosed in newborns and develops progressively during puberty. It is estimated to occur in approximately one in 500-1000 births and is generally more frequent in males (male: female ratio = 3: 1). The opposite deformity, also common among thoracic deformities, is known as Pectus Carinatum.

The etiology of the Pectus Excavatum remains unknown, although it can be considered as a hereditary condition. The suspicion is strong of an intrinsic disease on a molecular level of the cartilage of the costernal unions with a variable number and intensity. On rare occasions, the Pectus Excavatum is syndromic (Marfan, Morquio, Pierre Robin, Prune Belly, Poland, Jeune, etc.), although it usually occurs in isolation.

 

Diagnosis of Pectus Excavatum

Clinical diagnosis

The deformity is visible already in the first year of life. The patient’s respiratory pattern should be carefully observed. If sternal sinking occurs with inspiration, there is what is called a reverse or paradoxical breathing. This is correlated with an unfavorable evolution of the case. Monitoring will be carried out with visits every six months, which can be made more frequent in the event that the patient presents more serious respiratory disorders that require being admitted to hospital. Until approximately the age of four, it is not necessary to do any additional physical exam, since this adds nothing new.

Conventional radiology

It allows a look at the sternal sinking in the lateral view and the possiblity to taking the AP diameter measurement as well as the cross one. A metal or barium marker can be placed at the bottom of the deepest part. It also allows to see associated malformations, such as scoliosis, hemivertebrae, rib fusion, etc.

Computed tomography

Patients will undergo computed tomography (CT Scan or CAT) of the chest. Only a few funnel slices are requested, except in the case of a more complex deformity, in which case a helical CT scan may be used.

Conventional slices at the level of maximum subsidence allow to appreciate the degree of the Pectus Excavatum from the calculation of the Haller Index. This index is calculated by dividing the transverse axis (horizontal distance from the inside of the rib cage) by the anteroposterior axis (shorter distance between the vertebrae and the sternum) and correlates with the surgical indication when it is equal to or greater than 3.25 .

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Other complementary tests

Cardiac and pulmonary evaluations will also be done through:

  • Electrocardiograms
  • Echocardiograms, mandatory in all cases to obtain a state of the cardiovascular conditions.
  • Ergo-spirometries,  which are always performed in a protocolized way, after an effort, thereby obtaining patients’ breathing pattern (either restrictive or normal)
  • Limb telemetry, indicated in cases with accompanying scoliosis, without sternal rotation, in order to rule out limb dysmetry.

The monitoring of the patients requires in many cases to repeat some or all of the tests to assess stabilization or worsening evolution, and to prescribe the indication more accurately.

Pathophysiology of Pectus Excavatum

Approximately half of the affected cases of Pectus Excavatum will show clinical symptoms that will be due to the pathophysiological alteration of the deformity. Therefore, there will be a large population of patients with Pectus Excavatum who probably will not have symptoms nor will consequently have correction criteria.

In the affected cases, the shortening of the anteroposterior diameter of the thorax causes a deviation of the mediastinal viscera, generally towards the left hemithorax, which leads to a deviation of the cardiac axis to the left and a restrictive ventilatory pattern.

In these cases, deficits in blood filling can also be detected in the right chambers of the heart; cardiac displacement / rotation with a subsequent decrease in left ventricular ejection volume, and a reduced ability to pump efficiently; mitral valve prolapse; arrhythmias; or ventricular hypertrophy due to axial offset.

 

Symptomatology of Pectus Excavatum

The presentation of the deformity is visual and is noticeable in the first year of life, although it goes unnoticed due to the absence of symptoms, which will become evident in prepubertal age. The cases detected early must be monitored at least until that time, since this is when sports activity begins and the deficiencies that Pectus Excavatum causes are revealed.

Patients suffering from this deformity may experience:

  • Failure to adapt to physical activity
    The mediastinum deviation towards the left leads to a decrease in cardiac volume and, consequently, a failure to adapt to physical activity.
  • Respiratory problems
    Decreased tolerance for exercise tolerance, tiredness and shortness of breath, caused by decline in lung function or respiratory infections such as bronchopneumopathy, but also severe restrictions of pulmonary ventilation with a restrictive pattern.
  • Heart disturbances
    Precordial pain, palpitations, syncope, and arrhythmias may appear.
  • Morphological impairment of the spine
    It is common for Pectus Excavatum to occur not infrequently associated with scoliosis, which can cause chest or lower back pain.
    Scoliosis occurs in all cases with a certain degree of sternal rotation, which causes the ribs to rotate the vertebrae leading to deformation of the rachis, and not vice versa. All patients are born with the Pectus Excavatum without scoliosis, and this deformity appears over time in asymmetric cases.
  • Psychological disorders
    Many people affected by this chest deformity have behavioral disorders which can lead to solitude and social withdrawal.

Other manifestations

Many cases initially show a mild Poland sequence with chest hypoplasia of the breast and nipple, usually the right one, which is increased over time and worsens at puberty, especially in female patients.

TYPES OF PECTUS EXCAVATUM PATIENTS

  1. Asymptomatic patients with mild to moderate non-progressive deformity.
  2. Asymptomatic patients who have a severe and progressive chest deformity.
  3. Symptomatic patients with severe and progressive chest deformity, showing signs of lung or heart compression.
  4. Patients with Pectus Excavatum and other associated syndromes, such as Marfan syndrome, Poland syndrome, and severe heart abnormalities.