Background:After resection, specimens are subjected to formalin fixation during histologic processing. This procedure can result in tissue shrinkage, with amount of shrinkage related to tissue composition and tissue type.
Aims: In this study,we aimed to evaluated shrinkage of nasal mucosa and cartilage tissue and compared differences in shrinkage after resection, after formalin fixation, and during microscopic examination to understand differences in rate of shrinkage with different tissue types.
Study Design:Animal experimentation.
Methods:Fresh sheep nasal septa were excised (10 mm diameter in 40 sheep and 20 mm diameter in 40 sheep). The mucosa was separated from 1 side of the cartilage, with the contralateral mucosa remaining attached to the cartilage. Specimen diameters were measured in situ, after resection, after fixation for 6 or 24 hours (10% formalin), and during microscopic examination.
Results:We found no significant changes in specimen diameters (both 10 mm and 20 mm) between in situ and resected tissue. Shrinkage was noted in all fixated specimens, and further shrinkage was noted after microscopic examination. We found p=0.004 for free mucosa, p=0.005 for mucosa attached to cartilage, and p=0.008 for cartilage in 10 mm, and p=0.007 for free mucosa, p=0.004 for mucosa attached to cartilage, and p=0.01 for cartilage in 20 mm specimen diameter. Tissue shrinkage was greatest in free mucosal tissue and least in cartilage.
Conclusion: We found that tissue shrinkage was greatest in free mucosal tissue, less in mucosa attached to cartilage, and least in cartilage. These results should be considered when evaluating patients undergoing surgical procedures fornasal cavity and paranasal sinus malignancies. Surgical margins should be measured before fixation or evaluated if possible before fixation and shrinkage.