ectus excavatum is a malformation of the anterior P chest characterized by a posterior curvature of the lower two-thirds of the sternum, usually with the deepest point just above the xiphoid. The lower costal cartilages curve inward to form a broad symmetrical depression. The first and second ribs and costal cartilages, as well as the manubrium, are normal in most patients. Asymmetric deformities are common, with the concavity usually deeper on the right and the sternum rotated slightly, with the heart shifted into the left chest (Fig 1). Occasional patients may have protrusion of a few costal cartilages on the left. The chest wall characteristically has a decreased anteroposterior diameter. There is often an outward bowing of the lower costal cartilages over the abdomen, giving a “pot-bellied” appearance, particularly in younger children. An asthenic build and slumped posture are common. The pathogenesis of pectus excavatum remains unclear, but it has no relationship to rickets.’ An abnormality of the diaphragm or a band of tissue retracting the sternum posteriorly has been suggested; however, this is not supported by operative findings, or by the therapeutic ineffectiveness of simple retrosternal dissection. A recent theory is that the deformity results from an unbalanced growth in costochondral regions, further explaining the occasional asymmetric appearance, frequent association of other defects of osteogenesis and chondrogenesis, and the existence of the converse type of deformity, pectus carinatum. The involved cartilages are often fused, bizarrely deformed, or rotated. Resected cartilage segments occasionally show a disorderly arrangement of cartilage cells, perichondritis, and areas of aseptic necrosis. Abnormalities in the costal cartilages, with decreased levels of zinc and increased levels of magnesium and calcium, have been demonstrated.2 Pectus excavatum is inherited, although not clearly as a recessive trait. A member of the immediate family constellation with a chest wall deformity can be identified in approximately 40% of cases. The anomaly is believed to occur in as many as 1 in 400 births, but is uncommon in blacks and Hispanics (Personal communication, March 1995, March of Dimes Birth Defects Foundation, White Plains, NY). Other malformations may coexist, especially musculoskeletal anomalies, including scoliosis (16%), Marfan’s syndrome, clubfoot, and others. The deformity is usually apparent soon after birth, progresses slowly during childhood, and becomes much more severe during the rapid skeletal growth of early adolescence. Deep inspiration characteristically accentuates the deformity. Spontaneous regression rarely, if ever, occurs. During the past few years, many adults have sought surgical repair of pectus excavatum deformities that were not repaired earlier and that caused persistent symptoms and limitations in a~tivity.~ Symptoms are uncommon during early childhood, apart from an awareness of the abnormality and an unwillingness to expose the chest while swimming or engaging in other social or athletic activities. Easy fatigability and decreased stamina and endurance often become apparent during early adolescence when children become involved in competitive sports. In a severe deformity pulmonary expansion during inspiration is moderately confined in the relatively fixed thoracic compartment. Some very competitive children are able to compensate for the pectus-induced limitations in chest expansion in short-duration athletic activities with wider diaphragmatic excursions at a cost of greater energy expenditure. There is an appreciable incidence of chronic bronchitis, asthma, and occasional bronchiectasis, particularly in adolescents and adults. The xiphoid may be bifid, twisted, elongated, or displaced to one side.
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Mar 1, 2008
Ravindra K Vegunta + 3
Open Access