Effects of middle ear packing with collagen polyvinylpyrrolidone and hyaluronic acid in guinea pigs.

Objective: The aim of this study was to evaluate otoscopic and microscopic changes produced on the healthy mucosa of the middle ear (ME) and tympanic membrane (TM) of guinea pigs after packing with a collagen polyvinylpyrrolidone (CPVP) sponge soaked in hyaluronic acid (HA).

Material And Methods: In 24 guinea pigs, myringotomy on the right side was created and the ME was packed as follows: Group I (n = 6): Absorbable gelatin sponge (AGS) soaked in saline solution; Group II (n = 6): AGS sponge soaked in HA, Group III (n = 6): CPVP sponge soaked in saline solution, Group IV (n = 6): CPVP sponge soaked in HA. Four weeks after miringotomy, the ME and TM integrity and residual packing material were evaluated otoscopically. Histologically, we evaluated inflammatory changes on the ME mucosa.

Results: All animals in Groups I and II showed residual packing material (p < .001 ANOVA, TUKEY). Histologically, more inflammation was observed in Groups I, II, and III than in Group IV (p < .001 ANOVA, TUKEY). Group IV showed greater fibroblastic reaction (p < .02, ANOVA, TUKEY) versus other groups.

Conclusion: The CPVP sponge soaked in HA used as ME packing material is biocompatible and nontoxic, because it produces minimal inflammatory changes on the healthy mucosa of the ME and TM of guinea pigs. However, more research with injured mucosa is needed to validate its usefulness in otosurgery.