Wound healing in the rabbi tparanasal sinuses after Coblation: Evaluation for use in endoscopic sinus surgery

Background: Bipolar radiofrequency can be used surgically to excise and cauterize tissue simultaneously. It has potential for use in endoscopic sinus surgery (ESS). This study was performed to determine the extent and pattern of injury in the paranasal sinuses with bipolar radiofrequency and evaluate wound healing. Methods: Eight rabbits underwent Coblation of maxillary sinus mucosa with biopsy immediately, on postoperative day (POD) 3, 7, 14, or 29. Maxillary mucosa was exposed through the nasal dorsum, and a Coblator PROciseXP wand used on a power setting of 7 for 2 seconds. Three of the rabbits also had Coblation of ethmoid mucosa over the lamina papyracea, after extending the maxillary ostomy, with biopsy immediately. Results: Coblation resulted in immediate loss of surface respiratory epithelium and thermal-type injury to the underlying seromucinous glands. On POD 3, the site showed reepithelialization with squamous metaplastic epithelium. The seromucinous glands underwent coagulative necrosis. At POD 7, there was partial replacement of overlying epithelium by respiratory epithelium. The underlying seromucinous glands were lost and replaced by fibroblastic proliferation, with less fibrosis than the mechanically created ostomy site. The underlying bone had reactive, regenerative changes. On PODs 14 and 29, there was further regeneration of respiratory epithelium. Fibrosis was mild. Coblation resulted in gross violation of the bony wall in one maxillary sinus. There were no histological changes in the orbit. Conclusion: Rabbit paranasal sinus mucosa heals appropriately after Coblation injury.