Comprehensive management of paranasal sinus fungus balls: A Young-IFOS consensus statement.

BACKGROUND: Paranasal sinus fungus balls (PSFB) are a common form of surgically treatable, noninvasive mycosis. To date, no guidelines have standardized PSFB treatment or management of difficult cases (eg, immunocompromised or fragile patients). The clinical consensus statement presented herein aims to provide a comprehensive management guide to PSFB based on current evidence. METHODS: A multidisciplinary, international panel of 19 specialists judged statements in 3 rounds of a modified Delphi method survey. Statements encompassed the following PSFB management issues: definition, diagnostic workup; treatment indications and modalities; and follow-up. Otolaryngologists, maxillofacial surgeons, infectious disease specialists, and transplant physicians were considered the target audience. RESULTS: Among the 23 statements, 7 reached strong consensus and 16 reached consensus. Consensus was reached on the definition, diagnosis, and treatment modalities for PSFB. Postoperative follow-up modalities and scenarios with bacterial superinfection were the most debated issues. CONCLUSION: Until further data are available, these points provide a framework for the management of PSFB. Moreover, PSFB should be considered a noninvasive mycosis that is not necessarily symptomatic or related to odontogenic conditions. Although diagnosis may be incidental, endoscopy and single imaging (computed tomography or magnetic resonance imaging, with distinctive features) are required for diagnosis, whereas contrast medium would allow for differential diagnosis. Although treatment of PSFB should be considered mandatory before sinus augmentation and is recommended for symptomatic patients, immunosuppressed patients, or patients with planned immunosuppression, watchful waiting could be considered for asymptomatic patients with chronic rhinosinusitis who are provided with appropriate advice and assessment.

A 2 and 5-Year Longitudinal Analysis of 671 Consecutive Patients Diagnosed with Unilateral Vestibular Schwannoma.

OBJECTIVE: To analyse the 2 and 5-year outcomes of a cohort of patients with newly diagnosed vestibular schwannoma patients. STUDY DESIGN: Longitudinal cohort study. SETTING: Tertiary skull base referral unit. PATIENTS: Six hundred and seventy-one consecutive patients referred to the Cambridge Skull Base Unit between 2005 and 2010. MAIN OUTCOME MEASURES: 1) Treatment outcomes, 2) hearing preservation, 3) facial nerve function, and 4) gross tumor control. RESULTS: At initial diagnosis, 440/671(65.6%) of patients entered a watch, wait and rescan (WWR) pathway, 208/671 (31%) underwent primary microsurgical excision and 23/671 (3.4%) primary radiotherapy. Of patients who entered WWR, 144/440 (32.7%) exhibited tumor growth necessitating secondary intervention at a mean of 22.7 months; 67.4% had radiotherapy and 32.6% surgery. Radiotherapy was successful at achieving tumor control in 95% of cases. Primary surgery via the translabyrinthine route was performed in the majority of cases allowing for a radiologically clear surgical resection in 93% of cases. CONCLUSION: The Cambridge philosophy of treating the newly diagnosed vestibular schwannoma aims at preserving functional status where possible. In patients with small tumors it is recommended that they are placed on to a WWR pathway, of which 67.3% will not exhibit any growth by 5 years. If small tumors grow more than 2 mm by serial scanning, radiotherapy offers a high rate of tumor control. In patients with larger tumors more than 20 mm we would advocate microsurgical excision by the translabyrinthine route which offers excellent functional outcomes and gross tumor control.

The Use of Postoperative Antibiotics Following Endoscopic Sinus Surgery for Chronic Rhinosinusitis: A Systematic Review and Meta-analysis.

BACKGROUND: Endoscopic sinus surgery is performed for medically recalcitrant chronic rhinosinusitis. There is no universally accepted strategy regarding post-operative antibiotics despite the high rates of usage worldwide. The aim of this study was to analyse patient-reported and objective outcomes behind antibiotic use following endoscopic sinus surgery. METHODS: A search of electronic databases was performed. Eligible randomised controlled trials (RCTs) and observational trials were included. The primary outcome was patient reported outcome measures. Secondary outcomes were local infections, endoscopy scores and adverse events. Meta-analysis was performed. RESULTS: Of 1045 publications identified, 7 were included in the qualitative synthesis and 5 RCTs were included in meta-analysis. Antibiotic regimens varied between studies in terms of antibiotic selection, timing commenced and duration of use. Meta-analysis suggested no significant difference between placebo and antibiotics in patient reported outcome measures (standardised mean difference (SMD) -0.215, 95% confidence interval (CI) -0.637 to 0.207) or endoscopic scores (SMD -2.86, 95% CI -0.846 to 0.273). There was no consistent definition in reporting of infection; therefore, this outcome cannot be comprehensively considered. No severe adverse events were attributable to antibiotics. CONCLUSIONS: From the studies analysed, there is no level 1 evidence to suggest that antibiotics improved patient outcomes following sinus surgery. However, there was significant heterogeneity in outcome measures and no clear data exists regarding the effects of antibiotics on postoperative infections. The available evidence at present is not enough to make a recommendation in either direction. Further designed larger RCTs are required to investigate these questions in more detail.

Latest developments on topical therapies in chronic rhinosinusitis.

PURPOSE OF REVIEW: Topical therapies play an important role in the management of chronic rhinosinusitis (CRS). A detailed literature review was undertaken to appraise recent evidence surrounding current topical therapies and novel treatments used in the setting of recalcitrant CRS. RECENT FINDINGS: Effective sinus surgery aids in the delivery of topical therapies. Budesonide nasal rinses delivered by saline irrigation offer clinical and symptomatic improvements pre and postoperatively with a well-proven safety profile. Topical steroids may additionally offer direct antibacterial effects as per in-vitro testing. Topical antibiotics are not recommended in routine practice; however, they may be of benefit for short-term eradication therapy. Novel treatments are under keen investigation and include bacteriophage, colloidal silver and manuka honey. The evidence base for these treatments is not robust enough to recommend their routine use at present. SUMMARY: Topical steroids delivered in conjunction with saline nasal irrigation offer the best combination of treatments in CRS and should be considered a standard of care. Wide surgical access and aggressive surgical debridement of polyposis facilitates the delivery of steroid irrigations to sinonasal mucosa and is associated with improved long-term outcomes following endoscopic sinus surgery. The use of novel treatments remains within the research setting alone.

Prelacrimal approach for nasolacrimal duct excision in the management of lacrimal system tumours.

Purpose: To report a case of a lacrimal sac tumour and describe a prelacrimal approach to the maxillary sinus to excise the nasolacrimal duct in its management. To our knowledge, this approach has not been adapted to remove the nasolacrimal duct for the management of pathological processes involving the nasolacrimal system. Methods: A 58-year-old female patient presented with a 6-month history of epiphora. A lacrimal sac mass was identified, and a biopsy revealed squamous cell carcinoma. Surgical excision was performed via a combined external and endoscopic prelacrimal approach. Results: A prelacrimal approach to the maxillary sinus to excise the nasolacrimal duct in combination with an external approach facilitated an en-bloc excision of the nasolacrimal apparatus. This allowed preservation on the entire inferior turbinate following reconstitution of the lateral nasal wall at the completion of the procedure. Conclusion: The endoscopic endonasal prelacrimal approach to the maxillary sinus is a useful method to approach and excise the nasolacrimal duct in the management of nasolacrimal pathology.

Endoscopic transnasal repair of two cases of spontaneous cerebrospinal fluid fistula in the foramen rotundum.

We report two female patients aged 16 and 33 who presented with spontaneous cerebrospinal fluid (CSF) rhinorrhoea. Beta-2 transferrin was positive in both cases. Initial high-resolution CT showed fluid in the maxillary sinus but no obvious bony defect. MR imaging revealed maxillary sinus cysts with high signal on T2 sequences. Endoscopic transnasal surgery with intrathecal fluorescein was undertaken and in both cases a leak was identified from foramen rotundum and repaired. Both patients are symptom free at 6 months. These cases highlight the rare occurrence of spontaneous CSF leak from the foramen rotundum, and how they can be effectively repaired using the endoscopic transnasal approach.

Partial resection of the middle turbinate during endoscopic sinus surgery for chronic rhinosinusitis does not lead to an increased risk of empty nose syndrome: a cohort study of a tertiary practice.

BACKGROUND: The treatment of the middle turbinate (MT) during endoscopic sinus surgery (ESS) for chronic rhinosinusitis (CRS) remains a contentious issue with arguments both for and against its resection. The purpose of this study was to examine the clinical impact of partial MT resection (PMTR) during ESS, paying particular attention to the risk of developing empty nose syndrome (ENS) and alteration to olfaction. METHODS: This cohort study was performed on prospectively collected data. A total of 177 patients underwent ESS for CRS; 93 had PMTR and 84 MT preservation (MTP). Preoperative data collection included subjective symptom scores as per the Adelaide Disease Severity Score (ADSS), Lund-Mackay scores, and nasal polyp status. The Empty Nose Syndrome 6-Item Questionnaire (ENS6Q) was administered by telephone consultation and analyzed alongside postoperative symptom scores. RESULTS: There was no difference in ENS6Q scores in patients who underwent PMTR vs those who had MTP. Patients who underwent PMTR had a higher baseline disease on Lund-Mackay scoring, and were more likely to be nasal polyp patients and be undergoing revision surgery. ADSS scores demonstrated significant improvements in all rhinologic symptoms, with no difference between the cohorts. CONCLUSION: PMTR is an adjunctive procedure to ESS. This study has established that PMTR as performed by the senior author carries no additional risk of developing ENS symptoms as defined by the ENS6Q, and that it carries no additional risk to olfaction or other rhinologic symptoms. PMTR can be safely considered at time of ESS, especially in patients at risk of lateralization of the MT.

The implications of pneumomediastinum and subcutaneous emphysema for the paediatric otolaryngologist.

Three patients presented within a 6-month period with pneumomediastinum. The underlying cause in each was distinct. One case occurred due to blunt laryngeal trauma and required urgent surgical intervention due to a decompensating airway. The second case was related to tracheal perforation secondary to a myofibroblastic tracheal tumour and the final case was related to adenovirus upper respiratory tract infection. Pneumomediastinum may be spontaneous or secondary to an underlying cause. Children should be managed using a multidisciplinary approach. Investigation and management should be influenced by clinical stability and invasive procedures should only be considered in patients who exhibit respiratory distress.

Association of intracellular Staphylococcus aureus with prognosis in chronic rhinosinusitis.

BACKGROUND: Staphylococcus aureus (S. aureus) has been shown to exist within nasal epithelial cells in chronic rhinosinusitis (CRS) patients. This study investigates the localization of intracellular S. aureus (ICSA) in CRS patients, the associated histopathology changes, and their effect on long-term postoperative outcomes. METHODS: A prospective study of patients with CRS with and without polyps and control patients (n = 25, 15, and 8, respectively) undergoing endoscopic sinus surgery was performed. Validated patient reported symptom scores and objective endoscopic scores were collected preoperatively and 12 months postoperatively. Mucosal tissue samples were collected and examined for the presence of ICSA using immunohistochemical analysis. Tissue also underwent routine hematoxylin and eosin and Sirius Red staining to evaluate the inflammatory cell load and extent of fibrosis. RESULTS: ICSA appeared to localize to the perinuclear region of the pseudostratified columnar respiratory epithelium. ICSA was more prevalent in CRS without nasal polyps (CRSsNP) than in CRS with nasal polyps (CRSwNP) or controls (80% vs 56% vs 38%, respectively). ICSA positive status did not appear to influence symptom or endoscopic scores at the time of surgery nor 12 months postoperatively. Lymphocytes and total inflammatory cells were significantly increased in ICSA(+) group than ICSA(-) groups (36.4 vs 22.4 cells/area and 53.8 vs 29.1 cells/area, respectively). There was no difference found in fibrosis. CONCLUSION: This study indicated that ICSA was most prevalent in CRSsNP patients and was associated with increased lymphocytia and total inflammatory cells but not with worse symptomatology, endoscopy results, or basement membrane (BM) thickening.

Comparative study of nJ- and µJ-energy level femtosecond lasers: evaluation of flap adhesion strength, stromal bed quality, and tissue responses.

PURPOSE: To compare flap adhesion strength, stromal bed quality, and tissue responses after flap preparation using nJ- and µJ-energy level femtosecond lasers. METHODS: All corneal flaps were created by either VisuMax laser (µJ-energy level) or femto-LDV (nJ-energy level). Flap adhesion strength in the rabbits was measured with a tension meter 1 and 2 months postoperatively. To investigate tissue responses to laser delivery, immunofluorescence staining and TUNEL assay were performed 4 and 24 hours postoperatively. To assess flap bed smoothness, human donor corneas were used. Surface irregularities were graded based on scanning electron microscopy results. RESULTS: The flap adhesion strength in the VisuMax group at month 1 and 2 was 16.95 ± 1.45 kPa and 18.33 ± 1.81 kPa, respectively; and 12.31 ± 4.15 kPa and 13.85 ± 4.78 kPa in the LDV group, respectively. No significant difference was found between the groups. Fibronectin and apoptotic cells were largely absent at the central incision site in the LDV group, but were present in the VisuMax group. The smoothness of flap beds appeared similar for both groups. An observer scored the VisuMax group 8.00 ± 1.00 and the LDV group 7.33 ± 0.58 (P = 0.387). CONCLUSIONS: The flap adhesion strength increased over time after treatment with both lasers. The nJ-energy pulses produced minimal wound healing reaction and apoptotic cells along the incision plane. The application of an nJ-energy laser, which can incise the cornea without inducing significant damage to cells and wound healing reaction, offers great potential at reducing scarring following incisional laser stromal surgery.

Safety and efficacy of topical bacteriophage and ethylenediaminetetraacetic acid treatment of Staphylococcus aureus infection in a sheep model of sinusitis.

BACKGROUND: Treatment of sinonasal bacterial biofilms continues to be a challenge in modern rhinology. This study's objective was to assess the safety and efficacy of topically applied Cocktail of S. aureus specific phage (CTSA) alone and in combination with ethylenediaminetetraacetic acid (EDTA) for treatment of Staphylococcus aureus biofilms in vivo. METHODS: Using a sheep model of sinusitis, frontal sinuses (n = 6 per treatment) were flushed once daily with a CTSA (2 × 10(6) plaque forming units [PFU]/mL), with or without EDTA (0.075 mg/mL), and compared to a control flush containing saline and heat-inactivated CTSA. Safety was assessed using histology and scanning electron microscopy (SEM) after treatment for 3 days. Efficacy was assessed by quantifying the generation of S. aureus biofilms in the frontal sinuses after 5 days of treatment. Biofilm mass was compared between treatment groups and controls using LIVE/DEAD BacLight staining and confocal scanning laser microscopy to visualize the tissue sections. COMSTAT2 software was used to compute the biofilm mass present on tissue sections. RESULTS: Tissue morphology was conserved, with no significant signs of inflammation, when comparing control and test treatments. Furthermore, SEM analysis indicated test treatments were not toxic or damaging to mucosal cilia. COMSTAT2 quantification of biofilm showed a significant reduction in biofilm levels when comparing the control with CTSA (p = 0.0043), EDTA (p = 0.0095), and CTSA-EDTA (p = 0.0022) treatments. CONCLUSION: Results indicate that CTSA and EDTA are safe and efficacious for short-term topical application against S. aureus infection in a sheep sinusitis model, and have the potential to be translated to a clinical setting.

Safety evaluation of a sinus surfactant in an explant-based cytotoxicity assay.

OBJECTIVES/HYPOTHESIS: Biofilms are associated with clinical relapse following surgery for chronic rhinosinusitis. Encased bacteria are protected from innate immunity and antimicrobial therapy. Surfactants can disperse the biofilm into its planktonic phenotype so that traditional treatments may be effective. The aim of this study was to assess a surfactant for its cytotoxicity profile. STUDY DESIGN: In vitro explant-based cytotoxicity study. METHODS: Sinonasal mucosa harvested from patients undergoing sinus surgery was tested using an air-liquid interface explant system. Surfactant at 1×, 2×, and 3× manufacturer's recommended concentrations were compared to control (saline) and Zinc Sulphate (ZnSO4 ), a known cytotoxic agent. Culture supernatant was analyzed for lactate dehydrogenase (LDH) as a marker of cellular toxicity. After 7 days, specimens were imaged using structured histopathology and scanning electron microscopy. RESULTS: Application of surfactant at 1× concentration did not elicit an elevation in LDH, whereas ZnSO4 caused a significant rise 1 day after application. Specimens tested with a 2× and 3× surfactant demonstrated LDH rises 4 days and 2 days after application, respectively. Mucosa tested with the 1× surfactant and control demonstrated intact cellular structures on histopathology and preserved cilial ultrastructure on SEM. In ZnSO4 -treated specimens, marked cellular degradation and ciliary denudation occurred. CONCLUSION: The surfactant does not appear to elicit cellular toxicity using an in vitro explant model at the manufacturer's recommended concentration. At higher concentrations, there may be dose-related toxicity that requires further investigation. In vivo testing is required to prove its efficacy in the treatment of recalcitrant chronic rhinosinusitis. LEVEL OF EVIDENCE: N/A.

Intracellular Staphylococcus aureus: the Trojan horse of recalcitrant chronic rhinosinusitis?

BACKGROUND: Despite recent evidence suggesting that Staphylococcus aureus exists within the sinonasal epithelium of chronic rhinosinusitis (CRS) patients, certain questions remain. The intracellular environment may provide a protective niche for pathogenic bacteria to evade host immunity and yet provide a reservoir for reinfection. To date, no studies have examined the impact of this bacterial phenotype; therefore, this study was designed to evaluate the role of intracellular S. aureus on postsurgical outcomes. METHODS: This study included 51 patients undergoing endoscopic sinus surgery (ESS) for medically-recalcitrant CRS. Sinonasal mucosa harvested at the time of surgery was dually stained with fluorescent molecular probes and imaged using confocal scanning laser microscopy for biofilm and intracellular status. Patients were followed in their early and late postoperative course for evidence of ongoing disease and signs of clinical relapse. RESULTS: Intracellular S. aureus was identified in 20 of 51 (39%) patients, and all were associated with surface biofilm. Biofilm alone was found in 16 of 51 (31%) patients and 15 of 51 (29%) patients had no evidence of S. aureus. Intracellular positive patients had a significantly higher risk of late clinical and microbiological relapse (p = 0.014). In this study, biofilm status without coexisting intracellular bacteria did not appear to impact on outcomes. CONCLUSION: Clinical and microbiological relapse of disease following ESS is significantly associated with intracellular S. aureus. Evidence suggests that this disease association is independent to surface biofilm status. Intracellular bacteria should be taken into consideration when designing novel treatment strategies to lessen the chance of reinfection.

Gene expression differences in nitric oxide and reactive oxygen species regulation point to an altered innate immune response in chronic rhinosinusitis.

BACKGROUND: The complex interplay between host, environment, and microbe in the etiopathogenesis of chronic rhinosinusitis (CRS) remains unclear. This study focuses on the host-microbe interaction, specifically the regulation of nitric oxide (NO) and reactive oxygen species (ROS) against the pathogenic organism Staphylococcus aureus (S. aureus). NO and ROS play crucial roles in innate immunity and in the first-line defense against microbial invasion. METHODS: Sinonasal tissue samples were harvested from CRS and control patients during surgery. CRS patients were classified S. aureus biofilm-positive (B+) or biofilm-negative (B-) using fluorescence in situ hybridization and clinically as polyp-positive (P+) or polyp-negative (P-). Samples were assessed using an NO polymerase chain reaction (PCR) array containing 84 genes involved in NO and ROS regulation, and gene expression of all subgroups were compared to each other. RESULTS: Twenty-three samples were analyzed with 31 genes significantly changed, the greatest seen in the B+P+ CRS patients. Four genes consistently displayed differential expression between the groups including the cytoprotective oxidation resistance 1 (OXR1) and peroxiredoxin 6 (PRDX6), neutrophil cytosolic factor 2 (NCF2), and the prion protein (PRNP) genes. CONCLUSION: Alteration in gene expression points to impaired innate immune responses differing among CRS subgroups based on S. aureus biofilm and polyp status. The consistent alteration of 4 genes among distinct groups demonstrates that S. aureus biofilms and polyps are associated with specific changes in gene expression. Further studies are required to validate these findings in a wider cohort of patients and correlate this to protein expression and disease manifestation.

Identifying intracellular Staphylococcus aureus in chronic rhinosinusitis: a direct comparison of techniques.

BACKGROUND: The emerging concept of intracellular pathogens such as Staphylococcus aureus playing a role in chronic rhinosinusitis (CRS) has led to the development of numerous imaging techniques for their identification. Traditional methods of bacterial culture are not effective at localizing bacteria to the surface or within tissue samples. The aim of this study was to develop and validate a novel imaging technique using confocal scanning laser microscopy (CSLM) coupled with a fluorescence in situ hybridization (FISH) probe and nucleic acid counterstain (propidium iodide [PI]) that allows for simultaneous analysis of S. aureus intracellular status and surface biofilm within whole mucosal samples. METHODS: A prospective study was performed including 17 patients undergoing endoscopic sinus surgery for CRS. Tissue samples were analyzed with both CSLM-FISH/PI and immunohistochemistry (IHC) for intracellular S. aureus status. RESULTS: Using CSLM-FISH/PI intracellular S. aureus was identified in 9/17 (47%) patients and in 7/17 (39%) using IHC. Surface biofilm can be identified with CSLM-FISH/PI in the same piece of tissue; however, deeper imaging to the submucosa is impossible. IHC showed submucosal bacteria in three patients. CONCLUSION: Both CSLM-FISH/PI and IHC are complementary techniques that can be used to identify intracellular S. aureus. CSLM-FISH/PI allows for the simultaneous detection of intracellular status and surface biofilm within the tissue analyzed. IHC has a role in the identification of intracellular and submucosal S. aureus within these tissues. Additional investigation is required to identify the true pathogenic nature of intracellular organisms as well as any relationship to surface biofilm status.

Prevention of false positive binding during immunofluorescence of Staphylococcus aureus infected tissue biopsies.

Immunofluorescence is a fundamental tool used to analyse tissue and cell samples with a wide variety of available antibodies targeting specific proteins or molecules. Staphylococcal surface protein A is used both in clinical, research and industrial settings for its ability to bind mammalian immunoglobulin G. Spurious binding between protein A and IgG antibodies can lead to false-positive fluorescence and misleading results. Here we demonstrate this occurring in formalin-fixed patient samples that harbour Staphylococcus aureus infection, and characterise methods to overcome this issue. Specifically the use of F(ab') fragment antibodies or blocking with human IgG is shown to prevent antibody-protein A interaction in formalin-fixed S. aureus smears, biopsies obtained from infected patients, and experimentally infected tissue samples.

Reproducibility and age-related changes of ocular parametric measurements in rabbits.

BACKGROUND: The rabbit is a common animal model for ophthalmic research, especially corneal research. Ocular structures grow rapidly during the early stages of life. It is unclear when the rabbit cornea becomes mature and stabilized. We investigated the changes of keratometry, refractive state and central corneal thickness (CCT) with age. In addition, we studied the intra- and inter-observer reproducibility of anterior chamber depth (ACD) and anterior chamber width (ACW) measurements in rabbits using anterior segment-optical coherence tomography (AS-OCT). RESULTS: The growth of New Zealand White rabbits (n = 16) were monitored from age 1 to 12 months old. Corneal keratometric and refractive values were obtained using an autorefractor/keratometer, and CCT was measured using an AS-OCT. Keratometry and CCT changed rapidly from 1 to 7 months and appeared to be stabilizing after 8 months. The reduction of corneal curvature was approximately 1.36 diopter (D)/month from age 1 to 7 months, but the change decelerated to 0.30 D/month from age 8 to 12 months. An increase of 10 µm/month in CCT was observed from age 1 to 7 months, but the gain was reduced to less than 1 µm/month from age 8 to 12 months. There was a hyperopic shift over the span of 12 months, albeit the increase in spherical equivalent was slow and gradual. Rabbits of random age were then selected for 2 repeated ACD and ACW measurements by 2 independent and masked observers. Bland-Altman plots revealed a good agreement of ACD and ACW measurements inter- and intra-observer and the ranges of 95% limit of agreement were acceptable from a clinical perspective. CONCLUSIONS: Corneal keratometry, spherical equivalent refraction and CCT changed significantly during the first few months of life of rabbits. Young rabbits have been used in a large number of eye research studies. In certain settings, the ocular parametric changes are an important aspect to note as they may alter the findings made in a rabbit experimental model. In this study, we have also demonstrated for the first time a good between observer reproducibility of measurements of ocular parameters in an animal model by using an AS-OCT.

The multiplicity of Staphylococcus aureus in chronic rhinosinusitis: correlating surface biofilm and intracellular residence.

OBJECTIVES/HYPOTHESIS: The biofilm paradigm of chronic rhinosinusitis (CRS) is increasingly understood to play a key role in the pathophysiology of this disease. The role of intracellular infection of sinonasal epithelial cells has been suggested as a potential reservoir of pathogenic organisms that can lead to recalcitrant disease despite maximal medical and surgical treatment. Could a surface biofilm play a role in allowing intracellular infection to occur, and what are the factors associated with potential intracellular infections? The aim of this study was to investigate these questions. STUDY DESIGN: A prospective study including 36 CRS patients undergoing endoscopic sinus surgery and five control patients undergoing endonasal pituitary surgery. METHODS: Sinonasal mucosa harvested at the time of surgery was examined with a Staphylococcus aureus fluorescence in situ hybridization probe and propodium iodide counterstain using the confocal scanning laser microscope for both biofilm status and evidence of intracellular organisms. RESULTS: Intracellular S aureus was identified in 20/36 (56%) CRS patients compared to 0/8 (0%) control patients. CRS patients with intracellular infection were significantly more likely to harbor surface biofilm (20/20, P = .0014) and have a S aureus-positive culture swab (12/20, P = .0485). CONCLUSIONS: This study gives further evidence supporting a role of intracellular S aureus in CRS. In all cases intracellular infection was associated with surface biofilm, suggesting a potential relationship between the two. Further work is required to delineate the true mechanisms of intracellular persistence and also the role that it plays in the recalcitrant nature of CRS.