Figure 1.

Conditioned pain modulation in 27 patients suffering from painful posttraumatic trigeminal neuropathy (PTTN) and 27 healthy controls. Results show intraoral evaluations in the subjects' affected (injured) and contralateral trigeminal sites and on the dominant forearm. Data are presented as mean ± SD. Nonparametric analysis was used to compare the difference between study groups. The exact Wilcoxon rank sum test was used to compare the medians of 2 groups (PTTN and control), and the exact Kruskal–Wallis test was used to compare the medians across multiple groups (PTTN > 1 year, PTTN < 1 year, and controls). (A) Conditioned pain modulation was significantly (*) less efficient in patients with PTTN compared with the control group in the affected (injured) site and in the arm. Although similar pattern was observed in the contralateral trigeminal site, this was not statistically significant. (B) No significant differences in temporal summation were found between patients with PTTN and healthy controls. (C) Patients with PTTN with longer disease duration (more than a year) demonstrated significantly (*) less efficient conditioned pain modulation compared with the control group when tested intraorally in the affected area. (D) No significant differences in temporal summation were found between patients with PTTN suffering from the condition for more than a year, less than a year, and healthy controls.