*2.12.2.2 Tracheomalacia*

Respiratory symptoms occurring after repair of OA can be due to tracheomalacia. Tracheomalacia is defined as generalized or localized weakness of the trachea that allows the anterior and posterior tracheal walls to come together during expiration or coughing.

Symptoms of tracheomalacia are often difficult to clinically distinguish from those of recurrent TOF, anastomotic leak, or gastro-oesophageal reflux. Embryologic events leading to TOF are believed to contribute to the development of tracheomalacia [61]. The tracheal cartilage is shorter than normal, thereby failing to provide the support necessary to maintain a patent airway [61]. The trachea may also be compressed between the aorta anteriorly and the often dilated upper oesophagus posteriorly after repair of OA; and such compression has been considered a significant contributor to the pathophysiology of tracheomalacia [61]. The tracheal collapse usually occurs in the region of or just above the original site of TOF in the distal third of the trachea which is generally at the level of the aortic arch; and severe tracheomalacia appears less common in infants with pure OA. Tracheomalacia has broad clinical manifestations, ranging from a "brassy" or "barking" cough in mild cases to recurrent pneumonia or acute, life-threatening

apnoeic spells. Because of difficulty in breathing or cyanotic attacks during feeding, infants with tracheomalacia are often reluctant to feed. Life-threatening apnoeic and cyanotic spells occur during or within 5–10 min of a meal. They are characterized by cyanosis progressing to apnoea, bradycardia, and ultimately, cardiorespiratory arrest if not detected and managed promptly. Diagnosis is established by bronchoscopy with spontaneous ventilation. This reveals a slit-like lumen of the trachea at the involved area. However, because the symptoms overlap those of a stricture or gastro-oesophageal reflux, contrast oesophagogram is usually done as an initial investigation. Close attention to the tracheal air column on the lateral views during such a study will often reveal complete tracheal collapse during forced expiration (i.e., crying) or when contrast fills a distended upper oesophagus just above the anastomosis. Most mild to moderate symptoms of tracheomalacia tend to improve with time. Hence, operative intervention is not required. Operative treatment of choice for patients with severe symptoms, including acute life-threatening events, is aortopexy [46, 61, 66]. This is usually performed through a left anterior mediastinotomy (Chamberlain approach) or anterolateral thoracotomy [61]. The ascending aorta and arch are sutured to the posterior surface of the sternum after partial thymectomy [61]. The lifting of the aorta up in this fashion raises the anterior wall of the trachea and opens the tracheal lumen. In cases in which the aortic arch would not reach the posterior aspect of the sternum without undue tension, the use of a flap of pericardium based at the root of the aorta to be sutured to the sternum may be used [61]. Aortopexy and tracheopexy have also been done through anterior mediastinal approach via a low transverse cervical incision.
