Innominate artery compression of the trachea: relationship to cervical herniation of the normal thymus.

Abstract

To document the possible association of segmental tracheomalacia in the thoracic inlet with the combination of a large thymus and normal innominate artery. Eight infants with symptoms of innominate artery compression of the trachea were studied. The diagnostic approach included observation of posterior tracheal displacement and focal tracheal collapse at fluoroscopy, ablation of the right radial pulse by rigid endoscopic pressure, and compression of the anterior tracheal wall by the innominate artery at magnetic resonance imaging. Six patients had relief of symptoms with either thymectomy and innominate artery reimplantation (n = 4) or subtotal thymectomy and innominate artery suspension (n = 2). The ratio of the sagittal diameter of the thymus to the sagittal diameter of the thoracic inlet was significantly (P < .0009) higher in the symptomatic patients (0.58 +/- 0.03) than in age-matched control subjects (0.35 +/- 0.08). Crowding of the thoracic inlet by cervical herniation of an enlarged but normal thymus may contribute to the development of tracheomalacia and the symptoms of innominate artery compression.