Value of recurrent laryngeal nerve monitoring in the operative strategy during total thyroidectomy and parathyroidectomy

ObjectiveThe purpose of this study was to assess the role of recurrent laryngeal nerve (RLN) monitoring in the operative strategy during total thyroidectomy and parathyroidectomy. Due to the risk of serious respiratory complications of bilateral recurrent nerve paralysis, two-stage surgery may be considered in the case on negative stimulation of the first side.Patients and methodsThis prospective study was conducted in 100 consecutive patients between May 2007 and March 2011. Translaryngeal monitoring was performed. When stimulation of the RLN on the first side dissected was negative, dissection of the other side was deferred to avoid the risk of bilateral RLN paralysis.ResultsThe main surgical indications were thyroid carcinoma (34%), Graves’ disease (27%), multinodular goitre (27%) and parathyroid hyperplasia (9%) with seven cases of redo surgery. Four RLN identified on the first side gave a negative response to stimulation and surgery to the other side was therefore deferred. Transient unilateral RLN paralysis was observed in these four patients and two cases of RLN paralysis were observed among patients with positive RLN stimulation. Among the 96 contralateral RLNs tested, two were not visualized (one case of transient RLN paralysis, one case of permanent RLN paralysis), two gave a negative response to stimulation (two cases of permanent RLN paralysis) and 92 gave a positive response to stimulation (nine cases of transient RLN paralysis, including two cases associated with transient paralysis of the first side, and one case of permanent RLN paralysis). The incidence of RLN paralysis by nerve was 9.6% for transient RLN paralysis and 2% for permanent (unilateral) RLN paralysis.ConclusionWhen bilateral RLN dissection is planned, RLN monitoring is particularly useful to limit the risk of bilateral RLN paralysis. Two-stage thyroidectomy, following functional recovery of the damaged RLN, can therefore be proposed. The risk of bilateral RLN paralysis was avoided in four patients, while transient bilateral RLN paralysis was observed in two patients despite positive stimulation.