Research into novel therapeutic strategies for recalcitrant chronic rhinosinusitis (rCRS) has grown in the last few years. The biggest breakthrough came with monoclonal antibodies targeting type 2 inammation (i.e., dupilumab, mepoli­zumab, and omalizumab), which have shown efcacy for treating CRS with nasal polyps (CRSwNP) in large phase three clinical trials [1–3], followed by several

common antiseptic has been safely used for years in otolaryngology and other surgi­cal specialties. In vitro evidence shows that PVP-I solutions can disrupt Staphylococcus spp. biolms [20–22]. Moreover, PVP-I is active against a broad range of viruses [23, 24]. One trial showed that a single application of PVP-I can effectively eliminate nasal S. aureus carriage [25]. Nasal PVP-I irrigations are well tolerated by patients [26] and could serve as adjunct treatment during acute bacterial exacerbations or when chronic biolm is observed. In a prospective study done at our center, rCRS patients were treated with 0.08% PVP-I rinses for 7weeks and evaluated for changes in their Modied Lund-Kennedy (MLK) score and investi­gated for signs of thyroid toxicity or ciliary dysfunction. By the end of the follow-up period, 29 included patients decreased their MLK scores by at least one point, while thyroid and ciliary function remained normal [27]. One randomized controlled trial (RCT) involving 55 CRS patients undergoing primary endoscopic sinus surgery compared endoscopic and SNOT-22 scores of individuals randomized to PVP-I rinses versus those receiving normal saline [28]. After 3months of follow-up, the authors found no difference in clinical scores between the two groups. Finally, one trial involving 62 postsurgical CRS patients failed to demonstrate signicant differ­ences in endoscopic scores between PVP-I rinses, mupirocin rinses, and normal saline during acute bacterial exacerbations [26]. However, all three groups showed improvement at 30days compared to baseline. To date, there is no RCT evaluating PVP-I rinses in rCRS patients. Further research is needed to determine whether PVP-I can remove bacterial biolms invivo and improve endoscopic scores and quality of life in rCRS patients.

Manuka honey (MH), the product of a New Zealand scrub plant, has high concen­trations of antibacterial molecules including methylglyoxal (MGO), defensin-1, and hydrogen peroxide [29]. It has shown disruptive properties against S. aureus and other bacterial biolm invitro [30] and could be a potential alternative for sinonasal biolm control. The efcacy of MH for rCRS is still debated. In 1 single-blind pro­spective study of 34 recalcitrant AFRS patients, participants were asked to rinse 1 nostril with 2mL of a 50/50 mixture of honey-saline solution every day for 30days and saline on the other. At the end of the follow-up period, differences were seen in endoscopic scores between the two sides [31]. There are three RCTs evaluating MH for treatment of bacterial exacerbations of CRS [32–34]. In all three trials, MH treatment was associated with improvement from baseline at 14, 30, and 60days, respectively, but was not signicantly different compared to saline rinses. Treatment was well tolerated by patients, with no signicant adverse events associated with MH use. Similarly, one of the trials showed that smell was unaffected by MH use [32]. Although these results suggest that MH rinses are not superior to saline rinses, the trials were underpowered to detect small differences in endoscopic scores, were subject to varying degrees of confounding by indication (e.g., some participants received oral antibiotics or steroids after randomization at the discretion of the

treating clinician), and used different concentrations of MH, which makes compari­sons difcult. A large, well-designed RCT evaluating the use of MH as sole treat­ment or adjunct therapy for rCRS is still needed.

39]. The rst study compared a CS nasal spray to normal saline in 20 rCRS patients

light (i.e., placebo) for 3weeks. Notably, CRSwNP patients with a history of bacte­rial exacerbations and those with acute viral or bacterial infections were excluded. The authors found no difference in symptomatic scores after 3weeks of treatment and 1month follow-up. Unfortunately, the patient population in this trial is not well described, and there is little information on whether any of the participants had undergone ESS in the past, making it difcult for the reader to extrapolate their results. Combined, these studies are insufcient to answer whether mUV/VIS is effective for CRS but suggest a possible anti-inammatory effect in CRSwNP.