Pectus excavatum is the most frequent type of congenital chest wall deformities with one in 1000 children.
There is a male preponderance, and in some patients it is a familial lesion.

Unknown.

The depression of the sternum and of the adjacent pairs of ribs is wide and dell-like or narrow and deep, and asymmetrical or symmetrical, constituting 4 anatomical variations.
In addition, the funnel chest may be combined with a protrusion deformity (pectus carinatum).
Altogether, 3 types of depression deformities result.

In infants and toddlers one may observe inappetence, dysphagia, failure to thrive, inspiratory stridor, and akinesia.
In schoolchildren, psychological problems are in the forefront, such as loss of self-confidence and abnormal behavior (for instance, avoidance of public swimming pools). Especially boys may lament their limitations during sports competitions, or in some physical activities, such as cycling up-hill. In both sexes, typical cardio-respiratory symptoms and signs are rarely present in childhood.

The clinical presentation is according to the already mentioned anatomical types and variations. A general clinical examination is very important: muscular or asthenic posture, the latter with hanging shoulders, bowing of the upper part of the body, and protruding belly. In addition, scoliosis and other deformities of the spine, and combined malformations can be present.

The outer sagittal diameter of the thorax serves as an objective and reproducible measure (the depth of the sternum is one of the various elements of a depression deformity); it can be determined with a pelvimeter and includes the distance between the deepest point of the sternum and the opposite spinous process. In body lengths of 55, 105 and 155 cm, the values of 8, 12 and 14 cm or lower, respectively, are abnormal. Beside the body length and weight and their percentiles, deviations of the spine at rest and on defined movements must be determined. Also, a photographic documentation of the deformity is necessary with shots taken from the front and from both sides with an oblique view.

See Pathophysiology and clinical presentation.

The following points are important for therapeutic and prognostic reasons:
1. A spontaneous resolution of a funnel chest is unusual, even if the malformation is already present in infancy.
2. A delay of surgery up to the second decade, when the pectus excavatum becomes symptomatic, and the patient can express his or her own opinion concerning surgery, has many disadvantages; especially the expense of surgery is larger while the results may be less favorable.

With the knowledge of the clinical features of a pectus excavatum and a precise clinical examination, there is no differential diagnosis except for:
a) types with a combination with a pectus carinatum (protrusion deformity),
b) strictly localized congenital deformities of the chest wall, and
c) acquired pathologies without/with previous thoracic surgery.

The additional examinations serve as an objective definition of the type and the degree of funnel chest or another chest wall deformity.
Chest x-rays in two planes: Determination of the inner sagittal diameter between the inner sternal surface and the anterior part of the opposite vertebral body (< 5, 7 and 8 or less cm, respectively = abnormal values for the body lengths mentioned above) and of other distances and indices. Moreover, visualization of possible anomalies of the spine and the respiratory and cardio-vascular system.
CT: Determination of the CT-Index = transverse diameter divided by the sagittal diameter of the thorax, and 3-dimensional reconstruction of the chest wall deformity.
Photographs: Visually possible comparison of the local findings prior to and after surgery, which is understandable to both the parents and the patient.
Pulmonary functional tests (pre- and postoperatively, frequent associated asthmoid bronchitis) and echocardiography (dilatation of the aortic root in Marfan syndrome).

In contrast to the pectus carinatum, there is no other therapy in funnel chest than surgery, and the indications are:
a) obvious functional and/or psychological embarrassment;
b) for relief of extreme kyphotic and other deformities of the vertebral column;
c) significant deviations of the radiologically obtained measurements, e. g. of the Haller CT-Index (Haller JA Jr et al. J Pediatr Surg 22:904,1987).
Possible procedures are:
a) open surgery according to Ravitch without implants, and
b) thoracoscopically guided elevation of the funnel chest according to Nuss with implants.

With open surgery, the deformity remains relieved in more than 80 %, and physical activity is restored distinctly. Nevertheless, at least in open surgery there is a decreased elasticity of the chest wall.

For the Nuss-procedure which was initiated in 1998, long-term data over many years are not yet available, and beyond puberty the procedure is more difficult to perform. The early results are excellent or good in more than 90 % while asymmetric variants of funnel chest are less suitable for this type of surgery (Hosie S et al and Nuss D et al: Eur J Pediatr Surg 12:235 and 230, 2002).

In general, a more advanced age at the time of surgery, and an asthenic posture are unfavorable conditions for surgery. Recurrences occur with both procedures. In Nuss-procedure the implants are removed 2 to 4 years later.