Mucociliary activity and ultrastructural abnormalities of regenerated sinus mucosa in rabbits

The purpose of this study was to observe histologic findings in the regenerated maxillary sinus mucosa and restoration of ciliary activity by measuring the speed of mucociliary transport after complete surgical removal of the maxillary sinus mucosa. The maxillary sinuses of 32 rabbits were opened anteriorly and one side of the sinus mucosa of each animal was completely removed. In 16 animals, the natural ostia were widened, and, in another 16 animals, the natural ostia were left undisturbed. The contralateral, sham-operated sinus was used as a control for each animal. The animals of each group were reanesthetized and the maxillary sinuses were reopened at planned intervals. The speed of mucociliary transport toward the maxillary ostium, determined by India ink particle movement, was reduced to 6.4 mm/min, whereas it was 10.8 mm/min in the control side. Beating cilia were observed in 16% by dark-field microscopy, in contrast to 66% in the control sinus. Pseudostratified columnar epithelia without cilia were present in 12%, with the remaining consisting of pseudostratified ciliated columnar epithelia (88%). Light microscopic examination showed increase in submucosal fibrotic proliferation, decrease in submucosal glands, and infiltration of inflammatory cells. Under transmission electron microscopy, abnormal cilia such as compound cilia or edematous cilia were frequently found in the regenerated specimens. These observations suggest that mucociliary clearance of the regenerated sinus mucosa may be significantly diminished compared with that of the original mucosa.