Unilateral phrenic nerve paralysis: a rare complication after total thyroidectomy for a large cervico-mediastinal goitre

Unilateral phrenic nerve paralysis is a rare complication of cervico-mediastinal goitre. It occurs when adhesions grow between the intrathoracic part of the thyroid and the nerve, specially where the goitre enters the mediastinum behind the first rib. The damage may be caused by strain of the nerve due to the descent of the goitre into the chest or may be caused by the surgical manoeuvres during thyroidectomy performed by cervical approach. Two patients operated on for large cervico-mediastinal goitre are reported: a 70-year-old male with a large intrathoracic growth of the left thyroid lobe and a 54-year-old male with a large intrathoracic growth to the right lobe. A few days after total thyroidectomy they showed signs of exertional dyspnoea. The exams performed showed hemi-diaphragm relaxatio due to phrenic nerve paralysis, with resulting reduction of respiratory space. Phrenic nerve paralysis may follow total thyroidectomy for large cervico-mediastinal goitres; is not due to the operative technique, but rather to the particular anatomic conditions which may be found.