Recurrent laryngeal nerve injury in thyroid surgery

Vocal cord paresis or paralysis due to iatrogenic injury of the recurrent laryngeal nerve (RLNI) is one of the main problems in thyroid surgery. Although many procedures have been introduced to prevent the nerve injury, still the incidence of recurrent laryngeal nerve palsy varies between 1.5-14%. The aim of the present study is to assess the risk factors of recurrent laryngeal nerve injury during thyroid surgery.

Patients who had thyroid surgery between 1990 and 2005 and were admitted to the surgical department of King Fahd hospital of the University, Al-Khobar, Saudi Arabia were enrolled for this retrospective review, Factors predisposing to recurrent laryngeal nerve injury were evaluated such as pathology of the lesions and the type of operations and identification of recurrent laryngeal nerve intra-operatively. Preoperative and postoperative indirect laryngoscopic examinations were performed for all patients.

340 patients were included in this study. Transient unilateral vocal cord problems occurred in 11 (3.2%) cases, and in 1 (0.3%) case, it became permanent (post Rt. Hemithyroidectomy). Bilateral vocal cord problems occurred in 2 cases (0.58%), but none became permanent. There were significant increases in the incidence of recurrent laryngeal nerve injury in secondary operation (21.7% in secondary vs. 2.8% in primary, p=0.001), total/near total thyroidectomy (7.2% in total vs. 1.9% in subtotal, p=0.024), non-identification of RLN during surgery (7.6% in non-identification vs. 2.6% in identification, p=0.039) and in malignant disease (12.8% in malignant vs. 2.9% in benign, p=0.004). However, there was no significant difference in the incidence of recurrent laryngeal nerve injury with regards to gender (4.1% in male vs 3.8% in female, p=0.849).

The present study showed that thyroid carcinoma, re-operation for recurrent goiter, non-identification of RLN and total thyroidectomy were associated with a significantly increased risk of operative recurrent laryngeal nerve injury.