Recurrent laryngeal nerve management in thyroid surgery: consequences of routine visualization, application of intermittent, standardized and continuous nerve monitoring

Abstract

The objective is to compare the consequences of routine visualization (RV) and the application of intermitted (I-IONM), standardized (S-IONM), and continuous monitoring (C-IONM) of recurrent laryngeal nerve (RLN) management. RV includes that 698 RLNs managed solely with visual identification. In a second period 777, RLNs were handled by the I-IONM. The third period 768 RLNs monitoring was performed according to the standards. C-IONM via VN stimulation included 626 RLNs. The following issues were analyzed and compared per each period study: RLN identification rate, branching detection, assessment of NRLN, intraoperative recognizable nerve damage, stage thyroidectomy rate, transient or definitive lesions, bilateral nerve palsy, and recovery time. Significance for nerve identification rate was achieved (p = 0.03) when the statistical analysis was applied between RV vs. S-IONM and C-IONM. Extralaryngeal bifurcation was identified in 21, 44, 43, and 46 of RLN dissected, respectively, per period (p = 0.005). The incidence of paralysis in identified and unidentified RLN was 3.8 % (107/2806) and 82 % (52/63), respectively. Rates of temporary/permanent RLNP were 16.7/1.7, 5/1.1, 4.5/1, and 3.1/0 % per period study, respectively (p = 0.07). Recognizable intraoperatively nerve damage was, respectively, 15, 45, 100, and 100 % for period study (p = 0.03). The recovery of injured nerves was significantly faster in C-IONM group. S-IONM and C-IONM cumulate 40-stage procedures. The standardized technique, guidelines adherences, and C-IONM allowed to (1) increase RLN identification; (2) reduce the severity of injuries in terms of (a) reset bilateral RLNP, (b) faster recovery time, and (c) lower definitive RLNP; (3) gather detection of branching and NRLN; (4) recognize nerve stress; and (5) cumulate stage procedures.