The biochemical study of intermaxillary fixation (IMF) stress in oral surgery inpatients

Although intermaxillary fixation (IMF) is performed to treat the patients with maxillary fracture, this procedure is very stressful to the patients. IMF has been reported to increase noradrenaline (NA) release in the brain and elevate plasma corticosterone contents in the rat. These changes were significantly attenuated by diazepam, an anxiolytic of the benzodiazepine family. These results suggest that IMF could greatly affect the pituitary-adrenal system as a stress. In the present study, in order to examine the influence of IMF on the human body function, we measured levels of 17-hydrocorticosteroids (17-OHCS) and 17-ketosteroid (17-KS), which are metabolites of the adreno-cortical hormone cortisol, in the urine of inpatients undergoing IMF. The subjects were requested to fill out a questionnaire on irritableness caused by IMF. In these patients, urinary 17-OHCS levels were significantly increased after IMF and well correlated to the results of the questionnaire. The finding suggested that urinary 17-OHCS levels reflect stress related to IMF, and that such stress mainly causes an irritated feeling. Natural killer cell activity (NK activity), which is considered to be related to stress, was measured in these patients. The relationship between 17-OHCS levels and NK activity was examined in reference to the results of the questionnaire. Questionnaire showed that most patients noted insomnia and an irritated feeling during IMF. To examine the influence of anxiolytic agents on stress related to IMF, an anxiolytic agent, ethyl loflazepate, was administered during IMF, and urinary 17-OHCS levels were measured. There was no correlation between 17-OHCS levels and NK activity in the patients. Furthermore, no correlation was observed between visual analogue scale (VSA) and NK activity. Increases in 17-OHCS levels in the group treated with ethyl loflazepate, an anxiolytic of the benzodiazepine family, were significantly lower than in the untreated group. This suggests that ethyl loflazepate reduced stress responses to IMF. It has been reported that NK activity is reduced inpatients with depression or chronic fatigue syndrome. However, NK activity may not be affected by mechanical stress such as IMF. The finding that an anxiolytic agent, ethyl loflazepate, inhibited stress responses to IMF further suggests that anxiolytic drugs are very useful for treatment of irritated feeling of the patients undergoing IMF.