The Basis of Preoperative Vocal Fold Paralysis in a Series of Patients Undergoing Thyroid Surgery: The Preponderance of Benign Thyroid Disease

School of Medicine, Chung-Shan Medical University, Taichung, Taiwan.
Thyroid: official journal of the American Thyroid Association (Impact Factor: 3.84). 08/2011; 21(8):867-72. DOI: 10.1089/thy.2010.0280
Source: PubMed

ABSTRACT Preoperative vocal fold paralysis (VFP) is thought to be rare in patients with benign thyroid disease (BTD). In contrast with cases of malignancy, in which the recurrent laryngeal nerve (RLN) should be severed, in patients with BTD and VFP the RLN can be preserved without threatening patients' lives. This study investigates the clinical features that enable identification of patients who have VFP associated with BTD.
Medical records of 187 consecutive patients who underwent thyroid surgery were retrospectively reviewed. The association between preoperative VFP and pathology (benign or malignant), clinical features, and treatment results of patients with BTD and VFP were analyzed.
Of the 187 patients, 145 patients had BTD and 8 of these cases (5.52%) had preoperative unilateral VFP. The prevalence of BTD with VFP was 4.3% (8/187). The other 42 patients had malignant thyroid disease and 4 of these cases (9.52%) had preoperative unilateral VFP. None of the aforementioned VFP was caused by previous thyroidectomy or surgery to the neck. Although the relative risk of VFP in patients with thyroid malignancy was 1.726 (9.52%/5.52%), there was no significant association between VFP and malignancy. Of the eight patients with BTD, benign fine-needle aspiration cytology or frozen sections, goiter with a diameter larger than 5 cm, cystic changes, and significant radiologic tracheo-esophageal groove compression were the common findings. During thyroidectomy, the RLN was injured but repaired in three patients. Two events occurred in patients who had severe RLN adhesion to the tumor caused by thyroidectomy performed decades ago. Two of the five patients without nerve injury recovered vocal fold function. The overall VFP recovery rate for patients with BTD and VFP was 25% (2/8).
Preoperative unilateral VFP is not uncommon in thyroid surgery. Obtaining information on laryngeal function is of extreme importance when planning surgery, especially contralateral surgery. Goiter with preoperative VFP is not necessarily an indicator of malignancy. Benign perioperative cytopathologic findings with typical radiographic compression strongly suggest that VFP is caused by BTD. If, during thyroidectomy, the RLN is carefully preserved, recovery of vocal fold function may still be possible.

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