Chapter 96

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1648 PART 5 ■ Anesthetic, Surgical, and Interventional Procedures: Considerations can accommodate the repair, which includes closure of the sternal defect, repair of the diaphragmatic hernia, and closure of the omphalocele. 30 Pectus Excavatum Pectus excavatum accounts for approximately 90% of chest wall defects, with an incidence of 1 in 300 live births. The etiology is possibly related to the overgrowth of cartilage in the adjacent ribs, displacing the sternum posteriorly. Clinically, it presents more commonly in boys at a ratio of 3:1, becoming more progressive in posterior displacement as the child enters puberty. It is associated with Marfan’s syndrome (2% of cases), diaphragmatic abnormalities (2% of cases) and congenital heart disease (1.5%). 31 Patients may present asymptomatically or may have complaints of chest pain, palpitations, and asthma-like symptoms. There continues to be considerable debate about the clinical impact of this defect upon cardiovascular and pulmonary function. Intuitively, the compression of the heart and the lungs by the sternum should result in dysfunction. Lower lung volumes and decreased cardiac output have been recorded in patients with severe defects during exercise; 32–33 improvements in function have been demonstrated in patients postoperatively. Indications for surgical repair are more commonly psychological, related to issues around poor self-image, and less commonly related to issues of physiologic compromise of clinically relevant cardiopulmonary dysfunction; the latter may be important for a patient with a severe defect who also happens to be a competitive athlete. The occasional child with a concurrent diagnosis of Marfan’s syndrome or congenital heart disease should be considered for repair of the chest wall defect before open heart surgery to avert the issues of compression of the cardiac structures. The surgical options are essentially two: the Ravitch procedure (an open surgical approach) and the Nuss procedure (a minimally invasive approach). The former technique has been used for more than 50 years and has undergone minor revisions over time. Figure 96–11AB shows a patient with pectus excavatum before and after a Ravitch repair. Intraoperative and postoperative considerations include pneumothorax, hemorrhage, and pain management. In long-term follow-up, patients will experience minor recurrences of the defect in 10 to 15% of cases and major recurrences in 10 to 15% of cases for an overall recurrence rate of 20 to 30%. 34–35 Because of an infrequent but devastating long-term complication of thoracic dystrophy, children should be at least 6 years of age before undergoing surgical correction of this defect; some authors now recommend delaying repair until 12 to 16 years of age to reduce the chance of this complication. 36 The Nuss procedure has become the de facto procedure for the correction of pectus excavatum in the United States. The attraction of this technique is its cosmetically more acceptable outcome, because it eliminates the transverse chest incision of the Ravitch procedure and replaces it with two small lateral chest wall incisions; it functions on the premise that the chest wall can be remodeled over a nondeformable metal bar that forcibly pushes the sternum and ribs from the spine, increasing the anteriorposterior distance; the bar is usually left in place for 2 to 3 years to reduce the chance of recurrence of the defect. The intraoperative and postoperative considerations include pain management, pneumothorax, and metal bar displacement. More serious complications have included cardiac perforation, empyema, pericarditis, and the development of thoracic outlet syndrome. The overall complication rate is 20 to 28%, which is higher than for the Ravitch procedure (
CHAPTER 96 ■ Thoracic Surgery: Surgical Considerations 1649 A Figure 96-12. A and B: This series demonstrates a patient with pectus carinatum before and after a Ravitch repair (looking from the side of the patient). B defects may result in changes in pulmonary function, which should be assessed with a complete set of PFTs. The classical surgical treatment is similar to the approach for pectus excavatum with a Ravitch repair. This treatment, which usually yields a very good cosmetic result, is associated with a transverse scar across the low3er portion of the chest; figure 96– 12AB shows a patient with pectus carinatum before and after a Ravitch repair. As such, some authors have advocated the use of orthotic compression bracing of the chest wall to induce remodeling of the underlying ribs and sternum. 42–43 One of these studies found that the bracing led to positive outcomes, provided that the patients were compliant with wearing their compression vests. The difficulty with compliance was the requirement to wear the compression vest for 14 to 16 hours a day for 24 months. 44 The role of surgical intervention in this chest wall abnormality will likely decrease over time as the nonoperative options of bracing becomes more accepted and will only be reserved for children and adolescents who are noncompliant with the bracing regimen. DIAPHRAGMATIC ANOMALIES Among diaphragmatic anomalies, the most common are Bochdalek (or posteriolateral) congenital diaphragmatic hernias, at an incidence of 1 in 4000-5000 live births/year. This specific topic will be reviewed and discussed in Chapter 85. Other anomalies of the diaphragm, including Morgagni diaphragmatic hernias and diaphragmatic eventrations, will be discussed below. All of these hernias develop as a result of an abnormality of embryological development. The diaphragm, whereby the pleuroperitoneal cavity is separated into two distinct cavities, usually forms between 4 and 8 weeks of gestation. The diaphragm is normally composed of a central tendon and a peripheral muscular section; the former arises from the transverse septum and the latter arises from the posterolateral pleuroperitoneal folds. Some diaphragmatic anomalies form as a result of failure of fusion of the septum and folds; others arise from defects in formation of the diaphragmatic muscle itself. Morgagni diaphragmatic hernias develop as a failure of fusion in which the anterior diaphragm muscle attaches to the sternum. Morgagni Diaphragmatic Hernia Morgagni diaphragmatic hernias account for approximately 2% of all congenital diaphragmatic hernias. They occur in the anterior midline directly posterior to the sternum or in the parasternal location through the foramen of Morgagni. Unlike the classical Bochdalek congenital diaphragmatic hernia, these hernias usually present with features of intestinal obstruction instead of respiratory compromise. Usually, children are older when they become symptomatic, or defects are discovered incidentally on chest imaging. The hernia sac often contains a portion of the liver and transverse colon; occasionally it can also contain the small bowel and stomach, depending on size. These diaphragmatic defects can be surgically treated with open and laparoscopic techniques, including either primary closure of the defect or placement of a synthetic patch. The MAS approach has become the operation of choice for patients, who are not in any respiratory distress and can tolerate peritoneal CO 2 insufflation. Surgical repair involves a laparoscopic approach with either primary closure of the defect or placement of a synthetic patch. Video 2 demonstrates a laparoscopic view of a moderately-sized Morgagni hernia. Various authors have successfully applied this technique 45–46 ; in addition to primary closure of these defects, some of the authors were able to repair them with prosthetic patches with only one recurrence in long-term follow-up. Diaphragmatic Eventration Diaphragmatic eventration, which usually presents with unilateral elevation of a hemidiaphragm, can present as congenital or acquired disease. The former is a result of a defect in adequate muscularization of the diaphragm; in this case, the diaphragm is abnormally thin, often lacking muscle and being membranous in quality. 47 The latter is usually a result of iatrogenic injury of the phrenic nerve from surgery or from direct invasion of the phrenic nerve by a neoplasm; in this case, the diaphragmatic muscle is normal in quality. A portion of or all of the hemidiaphragm may be involved. The diagnosis can be made on history, especially in the case of acquired disease. Although most children with
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Chapter 96

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