Thyroidectomy for intrathoracic goiter: Surgical procedures, potential complications and postoperative outcomes

Albrecht von Haller first described an Intra-Thoracic Goiter (ITG) in 1749. Terms such as retrosternal, sub-sternal, intrathoracic, or mediastinal have also been used to define a goiter that extends beyond the thoracic inlet. Incidence in the general population, based on mass chest Computed Tomography (CT) screening, is 0.02 - 0.5%. The diagnosis of ITG is frequently made in the fifth or sixth decade of life, with a male/female rate of 1:4. ITG can be classified as either primary or secondary. Primary ITG (<1%) arises from aberrant thyroid tissue ectopically located in the mediastinum, receiving blood supply from mediastinal vessels and not connected to the cervical thyroid. Secondary ITG develops from the thyroid located in its normal cervical site; negative intra-thoracic pressure, gravity, and traction forces during swallowing facilitate downward migration of the thyroid into the mediastinum. The most common symptoms (dyspnea, choking, inability to sleep comfortably, dysphagia, and hoarseness) are related to compression of the airways and the esophagus. Less commonly, signs of compression of vascular and nervous structures are present, such as superior vena cava obstruction and/or Horner's syndrome. The diagnosis of ITG is based upon clinical history and examinations, and imaging findings. Nowadays CT scanning is the most comprehensive examination for the assessment of ITG extension and compression effects on adjacent anatomical structures. Surgical operations on large ITG are a major challenge in endocrine surgery. Surgery for ITG is required for the management of compression symptoms, potential airway compromise, and for the treatment of thyroid malignancy. While most ITG can be resected through a cervical approach, additional incisions, as manubriotomy, sternotomy, and lateral or antero-lateral thoracotomy, may be required. Lateral thoracotomy gives excellent exposure for a large posterior mediastinal goiter placed posterior to trachea with a crossover from the left side to the right side. During ITG operation, furthermore, there is a relevant rate of complications. The most frequent complication is the recurrent laryngeal nerve injury; the visual recognition of recurrent laryngeal nerve and a precise operative technique are still the most important factors for a successful operation. Another complication is parathyroid injury or blood supply impairment leading to postoperative hypocalcaemia. Postoperative hemorrhage is a rare but potentially fatal complication, occurring in 0.3 - 2%. In conclusion, in the presence of an ITG, extra-cervical access approach should be considered. The assessment and surgical treatment of ITG should be performed in specialized centers.