Optical coherence tomography for biofilm detection in chronic rhinosinusitis with nasal polyposis

Chronic rhinosinusitis with nasal polyposis (CRSwNP) is a multifactorial disease that seems to be associated with the presence of microbial biofilms and corresponding subepithelial inflammatory reactions. Optical coherence tomography (OCT) might be applied to detect bacterial and fungal biofilms in patients with CRSwNP. A total of 27 patients with CRSwNP undergoing endoscopic sinus surgery (ESS) were analyzed. The negative control group consisted of six patients undergoing septoplasty for nasal obstruction without CRSwNP. The nasal polyps and inferior turbinate mucosa specimens applied as negative controls were processed to OCT analysis and H.E. and Gram staining. Biofilm was detected in 22 of 27 patients (81.5 %) with CRSwNP and in none of six negative controls. In our series, OCT scan showed an obvious association with the findings of H.E. and Gram staining and was allocated to be a good predictor of biofilm existence. On OCT images, biofilms were displayed as distinct superficial layers with high optical density. It was found that microscopic architecture of biofilms was strongly associated with the integrity of nasal mucosa and to the cellular pattern of subepithelial inflammatory reaction. This study confirmed the presence of microbial biofilms in patients with CRSwNP according to OCT scans and histological analysis. Since biofilms may affect the severity and recurrence rate of CRS treated by ESS they should be detected preoperatively. In conclusion, single application of OCT analysis or combination with conventional histological protocols provides a robust and reliable method for the detection of bacterial and fungal biofilms in CRSwNP. Level of evidence 3b, individual case–control study.