vii. Recurrent Laryngeal Nerve Injury All patients will undergo preoperative and postoperative laryngoscopy the day after surgery. At the end of the operation, response of will be assessed by direct stimulation of the vagus nerve and the recurrent laryngeal nerve. Acoustic response and electrical amplitude will be recorded. In the absence of vocal cord abnormalities in the postoperative laryngoscopy, no further evaluations will be performed. If vocal cord paralysis or paresis were found in the postoperative laryngoscopy, patients will enter a voice rehabilitation program and subsequent laryngoscopies will be performed 2 weeks, 3 months and 6 months after surgery until recovery. Transient recurrent laryngeal nerve paralysis or paresis will be considered if vocal cord movement recovers in less than 6 months and the diagnosis of permanent vocal cord paralysis will be established if vocal cord abnormalities persist for more than 6 months. Differences will be analyzed using the Fisher´s exact test.