Radiofrequency volumetric tissue reduction of the inferior turbinate in a sheep model.

OBJECTIVES/HYPOTHESIS To validate the sheep model for endoscopic nasal surgery, and to utilize this model to compare the immediate and early postoperative histopathologic effects of four electrosurgical turbinate reduction techniques. STUDY DESIGN Pilot comparative study of electrosurgical devices for inferior turbinate reduction using a sheep model. METHODS Three radiofrequency devices (one monopolar and two bipolar) were compared to monopolar electrosurgery in a sheep model of inferior turbinate reduction. Procedures were performed according to device manufacturer guidelines using standard endoscopic instruments. Normative acoustic rhinometry data were obtained for the sheep model. Histopathologic analysis of turbinate specimens was performed at postoperative day 0 and 21. RESULTS Turbinate reduction was performed on seven sheep, one procedure on each side, yielding 14 turbinate specimens. Acoustic rhinometry was validated in the sheep model and demonstrated increased nasal volumes following decongestion and turbinate reduction. Submucosal destruction of glands and venous sinusoids and replacement with fibrosis were demonstrated as a common mechanism of action for all four electrosurgical devices. Epithelial disruption was seen with all devices on postoperative day 0. Squamous metaplasia and normal respiratory epithelial regeneration were documented variably between devices at postoperative day 21. CONCLUSIONS The sheep model is useful for study of both the anatomic and histopathologic effects of endonasal procedures. Standard endoscopic instruments and acoustic rhinometry can be used in this model with reproducible results. In this pilot animal study, radiofrequency devices for inferior turbinate reduction demonstrated greater preservation of normal nasal mucosal respiratory epithelium when compared to monopolar electrosurgery.