Comparison of a Handheld Device vs Endotracheal Tube–Based Neuromonitoring for Recurrent Laryngeal Nerve Stimulation

Objective: To measure the effect of thyroidectomy difficulty on intraoperative neuromonitoring false loss of signal (LOS) and to compare intraoperative endotracheal tube–based neuromonitoring (ETNM) and Checkpoint palpation-based direct stimulation (pDS) signals with postoperative laryngoscopy. We hypothesized that pDS has higher a positive predictive value for postdissection confirmation of recurrent laryngeal nerve function than ETNM and that this difference is accentuated with increasing thyroidectomy difficulty. Study Design: Prospective single-arm cross-sectional study comparing ETNM and pDS for patients undergoing hemi-, total, or completion thyroidectomy from July 2018 to March 2020. Setting: Single-surgeon series at a tertiary care hospital. Methods: Percentage concordance and positive and negative predictive values were measured. Each thyroidectomy was assigned a validated thyroidectomy difficulty score, and recorded recurrent laryngeal nerve signals were compared with postoperative vocal fold mobility. Results: Percentage concordance was 90.09%. Positive and negative predictive values were 0.19 (95% CI, 0.09-0.31) and 1.0 for ETNM and 0.59 (95% CI, 0.35-0.82) and 1.0 for pDS. The difference in positive predictive value was significant (0.40 [95% CI, 0.33-0.47], P <.001). False LOS rates for ETNM and pDS were 13.19% versus 3.30% (9.89% [95% CI, 1.80%-18.62%], P =.0155), 44.11% versus 0% (44.11% [95% CI, 25.80%-60.54%], P <.001), and 73.33% versus 13.33% (60% [95% CI, 24.76%-78.46%], P =.001) for the second through fourth thyroidectomy difficulty score quartiles, respectively. False LOS with ETNM was linearly correlated with increasing difficulty (R² = 0.97). Conclusion: ETNM was subject to high rates of postdissection false LOS that increased with thyroidectomy difficulty score. pDS is a reliable alternative that has higher positive predictive value than ETNM, particularly in more challenging cases such as those with posteriorly fixed thyroid cancers and fibrotic glands. Evidence level: 2.