ABSTRACT
OBJECTIVES: To investigate neurotoxic effect of bone cement (BC) on facial nerve by using electrophysiological and histopathological methods. METHODS: This study included 20 male albino Wistar rats, divided into four equal groups. Group A was designed as the control group, while group B was sham group. In the group C, BC solution was dropped onto the facial nerve trunks of rats and washed with physiological saline after 5 seconds. In the group D, BC solution was dropped onto the facial nerve trunks of rats and after allowing 5 minutes to dry, wounds were closed. Pre- and postoperative (on 4th week) evoked electromyography (EMG) measurements were done. For histopathological assessments, the rats were euthanized and tissue samples of facial nerve and surrounding areas were collected. RESULTS: According to the wave amplitude levels of evoked EMG, postoperative amplitude levels of group D were significantly decreased, compared to preoperative amplitude levels (P=0.043). We found no statistically significant difference in inflammation among the groups. In none of the groups, foreign body reaction and granulation tissue were not detected in any of the groups. In addition, degeneration in axon, myelin, or perineural nets was not detected in any of the groups. CONCLUSION: This study results suggest that BC has no direct toxicity on facial nerve, while it has indirect effects, by decreasing amplitude. Therefore, we conclude that direct contact of BC with nerve should be avoided, and the area should be cleaned by aspiration or washing with physiological saline in case of contact.
ABSTRACT
OBJECTIVE: Sodium-2-mercaptoethanesulfonate (MESNA) is widely used in medicine because of its antioxidant and mucolytic effects. In recent years, it has been used in otologic surgery. Because it cleaves disulfide bonds, it is used to easily dissect the epithelial matrix in cholesteatoma and atelectasis. In this study, we hypothesized that MESNA does not have any toxic effect on the facial nerve, and the effects of MESNA on the facial nerve were examined histologically and electrophysiologically. MATERIALS AND METHODS: Twenty Wistar albino rats were used. Groups A and B were designated as the control and sham groups, respectively. The animals in groups C and D were administered 20% and 50% of MESNA solution, respectively, after the facial nerve was exposed in the parotid region. Electromyography (EMG) measurements were performed preoperatively and postoperatively at 4 weeks. The animals were subsequently euthanized; facial nerve samples were taken for histopathological examination. RESULTS: When EMG parameters were compared within and between each group, preoperative and postoperative results were not statistically significantly different. Histopathological examination showed that MESNA did not cause any inflammation, granulation tissue, or foreign body reaction. CONCLUSION: To the best of our knowledge, the effects of MESNA on facial nerve functions have not been investigated. In this study, the effects of MESNA after direct application to the facial nerve were examined electrophysiologically and histologically, and it was determined that MESNA did not cause any toxic effects. It was concluded that MESNA can, therefore, be safely used during middle ear surgery.