OBJECTIVE: Local application of mitomycin-c (MMC) seems to be effective in reducing adhesions and stenosis after FESS. However this is not clearly seen in frontal sinusotomy. This study assesses the effectiveness of local MMC in the frontal ostium using a foamy material (otowick) and compared with cottonoids.METHODS: Forty-seven patients with chronic rhinosinusitis without polyps enrolled in this study. Two subgroups were studied: one with MMC application in one nostril using cottonoids and a second with MMC injected in an otowick. In all patients MMC was applied twice, intraoperatively and 4 weeks later. In both groups normal saline was applied to the other nostril on the same material with the MMC side. Six months postoperatively all patients were assessed endoscopically by a clinician blinded to the MMC side.RESULTS: Overall, MMC application was more effective than normal saline in both groups. Otowick use presented favorable initial results especially in primary cases regarding ostium patency, and need for revision surgery. The use of MMC cottonoids did not show any benefit in primary cases.CONCLUSION: The described technique seems to be effective in maintaining frontal ostium patency as it provides a more precise and deeper drug delivery to this area.