Thymectomy

Thymectomy is removal of the thymus gland, which sits in the front of the chest behind the sternum, on top of the pericardium and the great veins. The thymus is large in infants and shrinks and turns to fat after puberty. The operation is done to remove tumors of the thymus (thymoma and thymic carcinoma) and to treat myasthenia gravis, an autoimmune disease of muscle weakness that is closely linked to the thymus. The standard approach, and the one walked through here, is a median sternotomy: the sternum is split with a saw or sternal knife, and the whole gland is removed together with the fat around it, from the innominate vein down to the diaphragm and out to both phrenic nerves. Smaller tumors and myasthenia gravis are often treated through less invasive approaches instead: a small incision in the lower neck (transcervical), VATS, or robotic surgery. Bleeding from the thymic veins or the innominate vein, injury to the phrenic nerves, the heart or the pericardium, air leaks and chylothorax are the main risks. Patients with myasthenia gravis are stabilized before surgery and may have breathing problems afterward, so the drugs used to treat the disease and a tracheostomy tray should be at hand.