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Ototoxic effect of Ultrastop antifog solution applied to the guinea pig middle ear
Kazuhiro Nomura1, Hidetoshi Oshima2, Daisuke Yamauchi2
1Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan kazuhiroe@gmail.com.
Objectives:
Recent advances in endoscopic technology have allowed its application to middle ear surgery. An antifog agent is necessary for endoscopy because moisture and blood may obscure visibility. Ultrastop is one of the most commonly used antifog agents. The current study examined the ototoxic effect of topical application of Ultrastop in the guinea pig ear.
Study Design:
A preliminary experimental animal study.
Setting:
University hospital.
Subjects And Methods:
Eighteen male Hartley guinea pigs (weight, 480-620 g) were divided into 3 groups to be treated with Ultrastop, gentamicin (50 mg/mL, positive control), or saline solution (negative control). After auditory brainstem responses were measured, topical solutions of 0.2 mL were applied through a small hole made at the tympanic bulla. Posttreatment auditory brainstem responses were obtained 14 days after the treatment. The extent of middle ear damage was investigated and scored.
Results:
The saline-treated group showed no deterioration in auditory brainstem response threshold. The Ultrastop-treated and gentamicin-treated groups showed severe deterioration in auditory brainstem response threshold. Middle ear examination revealed extensive changes in the Ultrastop-treated group and medium changes in the gentamicin-treated group.
Conclusion:
Ultrastop applied topically to the guinea pig middle ear caused significant middle ear inflammation and hearing impairment.
