The Effects of MESNA on the Facial Nerve, an Experimental Animal Study.

Objective: MESNA (Sodium-2-mercaptoethanesulfonate) is a mucolytic substance that is used for chemically assisted tissue dissection in various surgical operations. The aim of this study was to address the issue of possible neurotoxicity from topical administration of MESNA solution on the facial nerve. We used different concentrations of MESNA solution and evaluated their effects on facial nerve by histopathological and functional analysis.

Materials And Methods: These groups were the saline administered group (control) (3 rats, 6 facial nerves), the 25% MESNA solution group (3 rats, 6 facial nerves), and the 100% MESNA solution group (3 rats, 6 facial nerves). Under general anesthesia (ketamine 150 mg/kg, xylocaine 4 mg/kg), the bilateral facial nerves of rats were dissected. The saline, 25% MESNA, and 100% MESNA solutions. Facial nerve functions of the rats were evaluated using mustachewhisker and blink reflex scores at day 20 days. On day 20, the rats were sacrificed and the buccal and marginal mandibular branches of the facial nerve were removed. The specimens were examined in terms of inflammation, granulation tissue, and foreign body reaction formation around the nerve. The functional and histopathological changes on facial nerves were compared between groups.

Results: Mustache and blink reflex scores of the rats were 5 (normal) in both the control and study groups. There were no statistically significant differences between the three groups in terms of facial nerve functions (p=1.00). On histopathologic examination, the 25% and 100% MESNA groups had significantly more inflammation compared with the control group (p=0.038 and p=0.007, respectively). There were no statistically significant differences between the 25% and 100% MESNA groups in term of inflammation (p > 0.05). There were no statistically significant differences between the three groups in terms of foreign body reaction formation (p > 0.05).

Conclusion: Topical administration of MESNA solution onto the facial nerve causes increased inflammation in both the 25% and 100% concentrations. Nevertheless, it does not cause any facial nerve dysfunction.