Evaluation of the Possible Neurotoxic Effect of the Bone Cement on the Facial Nerve: An Experimental Study

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.