Perspectives on the Etiology of Chronic Rhinosinusitis: An Immune Barrier Hypothesis

Background Chronic rhinosinusitis (CRS) has been defined as persistent symptomatic inflammation of the nasal and sinus mucosa resulting from the interaction of multiple host and environmental factors. Recent studies have implicated Alternaria fungi or toxigenic Staphylococcus aureus as critical agents in CRS pathogenesis. The emphasis on environmental agents in CRS etiology has focused interest toward elimination of those agents as the prime mechanism of therapy. This viewpoint is in marked contrast to the current perspective on some other chronic inflammatory epithelial disorders that afflict the skin, lungs, and gut, wherein host factors are believed to predispose to disease expression in the presence of ubiquitous environmental agents. Methods The current review evaluates CRS etiology from this perspective and considers that CRS develops, in part, as an outcome of a dysfunctional host response. Specifically, evidence from our laboratory and others will be reviewed indicating that CRS is associated with a failure of the mechanical and immunologic barriers across the nasal mucosa. The hypothesis would further propose that genetic and epigenetic variation predisposes susceptible individuals to barrier failure in the presence of environmental stress leading to CRS. Results From this unifying perspective, bacteria and fungi are seen as disease modifiers rather than primary etiologic agents. Conclusion The goal is to place concepts of CRS pathophysiology in a framework consistent with a current understanding of chronic inflammation in general and epithelial disease in particular.

In Vivo Laser Tissue Welding in the Rabbit Maxillary Sinus

Background One of the challenges in the current expansion of endoscopic sinonasal surgery is the ability to adequately reconstruct the skull base. Laser tissue welding (LTW) uses laser energy coupled to a biological solder to produce tissue bonds with burst thresholds exceeding human intracranial pressure. This technology could be used to reduce the rate of postoperative cerebrospinal fluid (CSF) leak. We performed this study to determine whether LTW can create durable tissue bonds in sinonasal mucosa that support normal wound healing and produce minimal collateral thermal injury. Methods Bilateral maxillary sinus mucosal incisions were made in 20 New Zealand white rabbits and one side was repaired using LTW. Burst pressure thresholds were measured on postoperative days 0, 5, and 15 and were compared with control using a two- way ANOVA and a post hoc Tukey test. Welds were examined histologically for thermal injury, inflammation, and fibroplasia and graded on a 4-point scale by three blinded observers. Results The burst pressures of the LTW group were significantly higher than control on postoperative day 0 (120.85 mm Hg, N = 4, SD = 47.84 versus 7.85 mm Hg, N = 4, SD = 0.78), and day 5 (132.56 mm Hg, N = 8, SD = 24.02 versus 41.7 mm Hg, N = 8, SD = 7.2; p < 0.05). By postoperative day 15 there was no significant difference between LTW (169.64 mm Hg, N = 8, SD = 18.49) and control (160.84 mm Hg, N = 8, SD = 14.16) burst thresholds. There was no evidence of thermal injury to the surrounding tissue in any group as well as no difference between experimental group and control with respect to inflammation or fibroplasia. Conclusion This is the first in vivo study showing that LTW is capable of producing tissue bonds exceeding human intracranial pressure with negligible thermal injury in sinonasal tissue. Welding can be performed endoscopically using a fiberoptic cable and may be useful in CSF leak and skull base repair.

Attachment-oriented Endoscopic Surgical Strategy for Sinonasal Inverted Papilloma

Background It is well documented that inverted papillomas (IP) have a localized attachment site. Still, instead of concentrating on the attachment site, endoscopic surgeons often perform an extended resection similar to the one achieved after external surgery. Objective Our objective was to evaluate an attachment-oriented endoscopic surgical strategy and to determine IP attachment diameter and location. Methods A prospective study was conducted. Thirty-three consecutive patients who underwent endoscopic IP excision (2001-2007) were enrolled. Thirty patients had adequate follow-up. Attachment diameters were measured in 25/33 patients. Surgery included debulking, identifying the precise mucosal attachment site, subperiosteal dissection and excision of the attachment, frozen section control, and resection/drilling of underlying bone. Results The mean measured attachment diameter (n = 25) was 8.4 ± 6 mm (range, 3-23 mm). Attachment locations included maxillary sinus (39%), ethmoid sinus (21%), nasal cavity (21%), frontal sinus (6%), sphenoid sinus (6%), lamina papyracea (3%), and cribriform plate (3%). The mean follow-up (n = 30) was 40 ± 21 months. Three patients had Krouse stage 1, 10 patients had stage 2, and 17 patients had stage 3. Nine patients had undergone previous surgeries. After attachment-oriented endoscopic surgery, three patients had persistent disease. Nasolacrimal duct stenosis was the only complication (n = 1). Conclusion Even advanced IP have small attachments. Their Identification facilitates efficacious resection with minimal morbidity.

Acoustic Rhinometry of Asian Noses

Background Each ethnic group has different nasal cavity geometries. The reference value of the minimal cross-sectional area (MCA) and the nasal volume (NV) is mandatory for rhinologic evaluation in regular practice and for research. This study was designed to study the normal value of acoustic rhinometry (AR) in Asian subjects in comparison with other ethnic groups. Methods AR was performed in 135 healthy Thai subjects. Subjects were divided into two groups: group I, with normal anterior rhinoscopic appearance; group II included subjects with asymptomatic, slightly deviated nasal septa. Results The mean of the MCA was 0.61 ± 0.60 cm2 before decongestion and 0.64 ± 0.14 cm2 after decongestion. The mean distance from the nostril to the point of MCA (D) was 1.66 ± 0.59 cm before decongestion and 1.41 ± 0.74 cm after decongestion. The mean of the NV measured between 0 and 4 cm was 3.66 ± 0.67 cm3 before decongestion and 4.18 ± 0.75 cm3 after decongestion. Before decongestion, there were no significant differences in the mean of the MCA, D, and NV between group I and group II subjects; however, there were significant differences in mean MCA and NV after decongestion. There were no differences in the parameters between male and female subjects before decongestion, except for the D, but after decongestion the mean values of the MCA, D, and NV were significantly higher in male subjects compared with female subjects. Conclusion The results of this study can be used as a reference value for Asian ethnicities. Thai subjects had measurements comparable with those of the European study and somewhat different from the study in black populations.

Comparison of Laryngeal Mask with Endotracheal Tube for Anesthesia in Endoscopic Sinus Surgery

Background The purpose of this study was to compare surgical conditions, including the amount of intraoperative bleeding as well as intraoperative blood pressure, during functional endoscopic sinus surgery (FESS) using flexible reinforced laryngeal mask airway (FRLMA) versus endotracheal tube (ETT) in maintaining controlled hypotension anesthesia induced by propofol-remifentanil total i.v. anesthesia (TIVA). Methods Sixty normotensive American Society of Anesthesiologists I—II adult patients undergoing FESS under controlled hypotension anesthesia caused by propofol-remifentanil-TIVA were randomly assigned into two groups: group I, FRLMA; group II, ETT. Hemorrhage was measured and the visibility of the operative field was evaluated according to a six-point scale. Results Controlled hypotension was achieved within a shorter period using laryngeal mask using lower rates of remifentanil infusion and lower total dose of remifentanil. Conclusion In summary, our results indicate that airway management using FRLMA during controlled hypotension anesthesia provided better surgical conditions in terms of quality of operative field and blood loss and allowed for convenient induced hypotension with low doses of remifentanil during TIVA in patients undergoing FESS.

Squamous Metaplasia and Chronic Rhinosinusitis: A Clinicopathological Study

Background The significance of squamous metaplasia (SM) in chronic rhinosinusitis (CRS) is unknown. The objectives of this study were to determine the prevalence of SM in histopathological specimens from patients with CRS and to correlate these histological findings with clinical features. Methods We reviewed the clinical records and pathological slides from 87 consecutive patients who underwent endoscopic sinus surgery for CRS. Demographic and clinical data, preoperative Chronic Sinusitis Survey (CSS) scores, and sinus CT stage were evaluated. Pathological slides were graded by a pathologist to characterize the degree of inflammation and SM, when present. CRS patients with and without SM were compared using student's t-test and χ2 test. Results Evaluation of the pathology slides revealed that 18.4% of specimens had SM present, whereas only 2.2% of pathology reports noted this. Histological grading of chronic inflammation showed significantly greater severity in specimens with SM (n = 16) when compared with the cohort without SM (n = 75; 100.0% versus 77.5%, respectively; p = 0.016). There was no difference in preoperative CT stage or the presence of hyperostosis on imaging, CSS scores, duration of CRS symptoms, or other clinical features between those with SM and those without SM (p > 0.05). Immunodeficiency was the only comorbidity more prevalent in the metaplastic group (12.5% versus 0%, respectively; p = 0.003). Conclusion SM is present in ∼18% of routine CRS specimens. It has a positive correlation with the severity of inflammation noted histologically in CRS but does not correlate with disease severity or chronicity, clinically.

Olfactory Bulb Volume in Patients with Sinonasal Disease

Background The aim of this study was to assess the volume of the olfactory bulb (OB) in patients with chronic rhinosinusitis (without nasal polyposis at the endoscopic evaluation) and to evaluate the correlation between this measure and the degree of sinonasal inflammation. Methods Patients with sinonasal disease (SND; n = 22) were compared with healthy controls (n = 16) using orthonasal and retronasal olfactory test results and OB volumes measurement calculated by planimetric manual contouring using standardized methods. The Lund-Mackay score (originally described for CT scan) was also used to gauge sinonasal inflammation (SND score). Results The two groups were not significantly different in terms of age or distribution of sex. Patients had significantly higher right- and left-sided SND scores than controls. There was no significant group difference between patients and controls with regard to OB volume. However, patients with an SND score ≥12 had larger OB volumes than patients with higher SND scores (p < 0.001). Even when controlling for the subjects’ age, a significant correlation was present between OB volume and SND score (r =-0.52; p = 0.001) with smaller OB volumes being associated with a higher degree of sinonasal pathology. Conclusion OB volume correlated with the SND score, which is an indicator of the degree of sinonasal inflammation. SND patients with a slight decrease or even normal olfactory function may already exhibit changes in their OB volume. This study also seems to emphasize the idea that OB volume changes are more sensitive to subtle changes in the olfactory system than results from psychophysical testing.