Continuous laryngeal nerve monitoring during thyroidectomy: Does it reduce the injury rate?

Abstract

Problem: To determine if continuous laryngeal nerve integrity monitoring (NIM) during thyroidectomy is associated with a decreased risk of postoperative recurrent laryngeal nerve (RLN) injury. Methods: This was a cohort study of 165 patients who underwent thyroidectomy at a resident teaching institution between 1999 and 2002. The control group had 120 nerves at risk (NAR) while the NIM group consisted of 116 NAR. Primary outcome measures included postoperative RLN paralysis, paresis, and total injury rates. Results: RLN paralysis occurred in 2.54% of NAR in the control group and 0.86% in the NIM group (RR = 0.34, CI95 = 0.04–3.27, P = 0.62). Temporary RLN paresis occurred in 4.24% of NAR in the control group and 3.45% in the NIM group (RR = 0.9, CI95 = 0.23–3.55, P = 0.89). Total RLN injury occurred in 6.78% of NAR in the control group and 4.31% in the NIM group (RR = 0.66, CI95 = 0.21–2.09, P = 0.48). When compared to all other NAR, advanced T-stage malignancy was associated with a significantly increased risk of RLN paresis (T4 RR = 9.0, CI95 = 2.56–31.67, P = 0.0006; T3+T4 RR = 7.5, CI95 = 2.17–25.86, P = 0.0001) but not paralysis. NIM use did not significantly reduce risk of RLN paresis in the advanced T-stage subset (T3+T4 RR = 0.36, CI95 = 0.04–3.0, P = 0.59). Conclusion: There were no statistically significant differences in RLN paralysis, paresis, or total injury rates between control and NIM groups, even in subsets with advanced T-stage and increased baseline risk. Advanced T-stage is a significant predictor of RLN paresis in this cohort. Significance: NIM does not appear necessary in routine thyroidectomy, although it may be considered in patients with T3 and T4 tumors given an increased risk of RLN injury in these patients. Support: None reported.