FIGURE 1. Cumulative distribution of stimulation thresholds after stimulation of the vagus nerve and of the recurrent laryngeal nerve. A, The recurrent laryngeal nerves were stimulated with 3-Hz pulses at currents ranging from 3 mA to 0.01 mA before (triangles) and after dissection but prior to wound closure (circles). The stimulation threshold of the vagus nerve was also recorded prior to wound closure (squares). The cumulative distribution was analyzed separately for patients undergoing surgery for benign disease (closed symbols) and for patients who were reoperated for benign disease (open symbols). B, The stimulation threshold was determined before wound closure in patients undergoing surgery for malignant disease (▴, recurrent nerve = recurrent-mal.; ▵, vagus nerve = vagus-mal.) and reoperation for malignant disease (◆, recurrent nerve = recurrent-mal. reop.; ⋄, vagus nerve = vagus-mal. reop.) The control curves for the recurrent laryngeal (•, recurrent-benign) and the vagus nerve (□, vagus-benign) correspond to patients undergoing surgery for benign disease and are the same as those in A. To normalize for the difference in nerves at risk in each group, the data are expressed as percent of total; the distributions were fitted to the logistic equation N=100* [I^P/(I^P + I_0.5^P)], where N is the number of nerves in % of total, I and I_0.5 are the individual threshold current and the median current in mA, respectively, and P is the slope factor.