Experimental sinusitis in a rhinogenic model.

Objectives/hypothesis: The objectives were to determine the optimal sinusitis induction period and to examine microbiological and histopathological changes of sinusitis recovery stage in a rhinogenic sinusitis model.

Methods: A synthetic sponge was inserted into the right-side nasal cavities of rabbits. The sponge was impregnated with a Streptococcus pneumoniae strain in group 1 and with sterile saline solution in groups 2 and 3. After the fourth day of sponge insertion, sinuses were examined by coronal computed tomography scans at two-day intervals until any radiological evidence of sinusitis was observed. When sinusitis was detected radiologically, five rabbits each from groups 1 and 2 were killed for histological examination. To determine the recovery period of sinusitis, sponges were removed from the rest of the rabbits in groups 1 and 2. Rabbits were selected randomly and killed on the 15th and the 30th days of the recovery period, immediately after radiological examinations. Group 3 was considered a sham group.

Results: Sinusitis induction was performed in all rabbits in groups 1 and 2 until the 8th day. After the sponges were removed, inflammation persisted until the 30th day of the study.

Conclusion: In a rhinogenic sinusitis model, although histological features of sinusitis were demonstrated, further studies are required to standardize this model and to examine whether or not the studied bacterial strain spreads from nasal cavity into sinus.