Nasal Anatomy and Function.

The nose is a complex structure important in facial aesthetics and in respiratory physiology. Nasal defects can pose a challenge to reconstructive surgeons who must re-create nasal symmetry while maintaining nasal function. A basic understanding of the underlying nasal anatomy is thus necessary for successful nasal reconstruction.

The relationship between nasal resistance to airflow and the airspace minimal cross-sectional area.

The relationship between nasal resistance (R) and airspace minimal cross-sectional area (mCSA) remains unclear. After the introduction of acoustic rhinometry, many otolaryngologists believed that mCSA measurements would correlate with subjective perception of nasal airway obstruction (NAO), and thus could provide an objective measure of nasal patency to guide therapy. However, multiple studies reported a low correlation between mCSA and subjective nasal patency, and between mCSA and R. This apparent lack of correlation between nasal form and function has been a long-standing enigma in the field of rhinology. Here we propose that nasal resistance is described by the Bernoulli Obstruction Theory. This theory predicts two flow regimes. For mCSA>Acrit, the constriction is not too severe and there is not a tight coupling between R and mCSA. In contrast, when mCSAAcrit (estimated to be 0.37cm(2)), this theory suggests that airway constrictions are rarely an exclusive contributor to nasal resistance, which may explain the weak correlation between mCSA and subjective nasal patency.

Simulating the nasal cycle with computational fluid dynamics.

OBJECTIVES: (1) To develop a method to account for the confounding effect of the nasal cycle when comparing preoperative and postoperative objective measures of nasal patency. (2) To illustrate this method by reporting objective measures derived from computational fluid dynamics (CFD) models spanning the full range of mucosal engorgement associated with the nasal cycle in 2 subjects. STUDY DESIGN: Retrospective. SETTING: Academic tertiary medical center. SUBJECTS AND METHODS: A cohort of 24 patients with nasal airway obstruction was reviewed to select the 2 patients with the greatest reciprocal change in mucosal engorgement between preoperative and postoperative computed tomography (CT) scans. Three-dimensional anatomic models were created based on the preoperative and postoperative CT scans. Nasal cycling models were also created by gradually changing the thickness of the inferior turbinate, middle turbinate, and septal swell body. Moreover, CFD was used to simulate airflow and to calculate nasal resistance and the average heat flux. RESULTS: Before accounting for the nasal cycle, patient A appeared to have a paradoxical worsening nasal obstruction in the right cavity postoperatively. After accounting for the nasal cycle, patient A had small improvements in objective measures postoperatively. The magnitude of the surgical effect also differed in patient B after accounting for the nasal cycle. CONCLUSION: By simulating the nasal cycle and comparing models in similar congestive states, surgical changes in nasal patency can be distinguished from physiological changes associated with the nasal cycle. This ability can lead to more precise comparisons of preoperative and postoperative objective measures and potentially more accurate virtual surgery planning.

Do you need to operate following recovery from complications of pediatric acute sinusitis?

OBJECTIVES: There are many studies that evaluate the role of surgery in the treatment of complications of pediatric acute sinusitis; however there are few studies, if any that report the incidence of surgery following recovery from acute complicated sinusitis. The goal of this study was to report the incidence and indications for surgical intervention after recovery from complications of pediatric acute sinusitis. METHODS: We reviewed the records of all children admitted to a tertiary care children's hospital between January 2005 and September 2010 with a diagnosis of sinusitis and an orbital or intracranial complication. Eighty-six patients met inclusion criteria. Charts were reviewed for type of complication, initial treatment (medical or surgical), type of procedure, secondary procedures, age, and comorbidities. Statistical analysis was completed using independent samples student t-tests and Mann-Whitney tests. RESULTS: A total of 86 patients with a mean age of 6.38 years (2 months to 18 years) were identified. Eighty patients had orbital complications while six presented with intracranial complications. Twenty-seven patients (31%) underwent sinus surgery during the acute phase of their illness whereas 59 patients (69%) were treated medically. After hospitalization and recovery for acute complicated sinusitis, surgery was performed on nine patients (mean age 4.86 years) within 1 month to 2 years post hospitalization. Of the nine patients who required secondary surgery following resolution of the initial complicated sinusitis, four patients were following initial surgical intervention and five patients had initially resolved their complication with medical therapy alone. Indications for subsequent surgery included failure of medical therapy for persistent rhinosinusitis (8 patients) and second complication (1 patient). CONCLUSIONS: This study suggests that following resolution of complicated pediatric rhinosinusitis, very few patients may need further surgical intervention. Subsequent intervention is best guided by clinical judgment, symptoms during outpatient clinic visits, and failure of medical therapy.