Background: When assessing the value of intraoperative nerve monitoring (IONM) during routine thyroidectomy, it is necessary to consider its influence on the surgeon's dissection technique. We investigated the effect of IONM on individual surgeon performance by determining the learning curve associated with this tool.
Methods: A one-year prospective study was conducted between May 2008 and April 2009 within a team of three experienced endocrine surgeons. The measure of surgical performance was based on the detection of immediate postoperative recurrent laryngeal nerve palsy by laryngoscopy. Individual learning curves associated with IONM acquisition were drawn with the cumulative sum (CUSUM) chart. Each surgeon was questioned about possible changes he had experienced in his own surgical technique after the introduction of IONM.
Results: A total of 475 consecutive patients who underwent thyroid surgery with IONM were included. The pattern of learning curves varied among surgeons and ranged from 35 to 304 procedures required for complete IONM acquisition. The surgeon with the longest learning curve also described a drastic modification of his technique related to nerve dissection.
Conclusions: Intraoperative nerve monitoring can induce changes in surgical practice. The different learning curve patterns among surgeons may reflect the variable degree to which surgeons will modify their own dissection technique. Such an effect on learning must be considered when assessing the impact of using IONM on patient safety.