Evaluation of sheep model with regard to healing of nasal epithelium after endoscopic sinus surgery
Date
2001
Authors
Shaw, Chi-kee Leslie
Editors
Advisors
Wormald, Peter-John
Journal Title
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Thesis
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Abstract
Four studies were performed to evaluate the influence of endoscopic sinus surgery (ESS) on the healing of nasal respiratory epithelium in a sheep model. The first study validated the sheep as a suitable animal model. As part of the standardization of the animal model a middle turbinectomy needed to be performed. The effects of middle turbinectomy on the nasal respiratory epithelium and cilial function were studied. At 3 weeks post turbinectomy the cilial function and histology of the respiratory epithelium was unchanged. The standardized and validated model could now be used to conduct further studies on the effect of ESS on respiratory epithelium. The second study investigated the effects of pre-operative packing with ribbon gauze and neuropatties on the nasal mucosa of sheep. Both ribbon gauze and neuropatties caused significant mucosal loss when compared with the control. The neuropatties caused less mucosal damage when compared with the ribbon gauze but this difference was not statistically significant. This damage to the epithelium is significant as it may add to the insult of ESS and may cause stasis of secretions with crusting in the post-operative phase. The third study assessed the temporal healing process of nasal epithelium after full-thickness and partial thickness mucosal removal in sheep. On day 84 post injury there was no significant difference between partial and full-thickness injuries. However there was a significant difference in the re-ciliation of the two types of wounds. The baseline mucociliary clearance did not differ significantly for either the partial thickness or the full-thickness wounded side. A significant interesting finding was that the healing process took much longer than expected and was still incomplete on day 84 when the sheep were sacrificed. This may account for some of the symptoms seen in the healing period in patients after ESS. The fourth study assessed cilial regeneration post mucosal injury by scanning electron microscopy. Using a new technique, two blinded observers validated the technique with little intra- or inter-individual difference seen when assessing the specimens. This technique may be useful in further studies as re-ciliation after surgery is crucial for nasal epithelium to gain health and normal function. This thesis has validated the sheep as a suitable animal model to study ESS and to evaluate factors that may play a role in the healing of nasal epithelium after surgery. Nasal packing was shown to cause a significant injury and should be used by ESS surgeons with caution. Full-thickness wounds should be avoided in the nose where possible as the re-ciliation was significantly reduced when compared to partial-thickness wounds. In addition the healing of nose took significantly longer than previously thought and was incomplete 84 days after surgery. Scanning electron microscopy was shown to be an important outcome measure for the healing of the nasal mucosa after ESS and a new technique for measuring the re-ciliation was validated.
School/Discipline
Department of Surgery
Dissertation Note
Thesis (MS) -- University of Adelaide, Department of Surgery, 2002
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