Background The effects of increases in maxillary sinus (MS) airflow following functional endoscopic sinus surgery (FESS) are unknown. The goal of this study was to quantify the effects of FESS on airflow into the MS in a cohort of patients with chronic rhinosinusitis, and compare MS flow rate with patient-reported outcome measures. Methods A pilot study was conducted in which preoperative and postoperative computed tomography scans of 4 patients undergoing bilateral or unilateral FESS were used to create 3-dimensional (3D) reconstructions of the nasal airway and paranasal sinuses using Mimics™ (Materialise, Inc.). The size of the maxillary antrostomies post-FESS ranged from 107 to 160 mm2. Computational meshes were generated from the 3D reconstructions, and steady-state, laminar, inspiratory airflow was simulated in each mesh using the computational fluid dynamics (CFD) software Fluent™ (ANSYS, Inc.) under physiologic, pressure-driven conditions. Airflow into the MS was estimated from the simulations and was compared preoperatively and postoperatively. In addition, patients completed preoperative and postoperative Rhinosinusitis OutcomeMeasure-31 (RSOM-31) questionnaires and scores were compared with MS airflow rates. Results CFD simulations predicted that average airflow rate into post-FESS MS increased by 18.5 mL/second, and that average flow velocity into the MS more than quadrupled. Simulation results also showed that MS flow rate trended with total RSOM-31 and all domain scores. Conclusion CFD simulations showed that the healed maxillary antrostomy after FESS can greatly enhance airflow into the MS. Our pilot study suggests that to some extent, increasing airflow into the MS may potentially improve chronic rhinosinusitis patients’ quality of life pre-FESS and post-FESS.

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OBJECTIVE To examine the relationship between Cerebrospinal Fluid (CSF) Rhinorrhea and Obstructive Sleep Apnea (OSA). STUDY DESIGN Retrospective chart-review of patients who underwent surgical repair of encephaloceles and/or CSF rhinorrhea at a tertiary medical center over a 12 year period. METHODS Pertinent demographic, clinical and surgical data including age, sex, medical and surgical history was obtained. Patients were classified by etiology of CSF leak into a spontaneous leak group and a non-spontaneous leak group, which included patients with documented trauma, malignancy, or known iatrogenic injury. RESULTS We retrospectively identified126 patients who underwent repair of encephalocele or CSF rhinorrhea. Of these, 70 (55.5%) were found to have a spontaneous etiology, while 56 (44.4%) had a non-spontaneous cause. Patients with spontaneous CSF rhinorrhea were more likely than their non-spontaneous counterparts to have a diagnosis of obstructive sleep apnea (OSA, 30.0% versus 14.3%, p=0.0294) and radiographic evidence of an empty sella on MRI (55.4% vs. 24.3%, p=0.0027). Overall, patients in the spontaneous CSF rhinorrhea group were more likely to be female compared to the non-spontaneous group (84.3% versus 41.1% female, P=0.0001). CONCLUSIONS Our study shows that patients with spontaneous CSF rhinorrhea are significantly more likely to have a diagnosis of OSA compared to those with non-spontaneous causes of CSF leaks, or to the general population (incidence of 1-5% in various population studies). Given the known association between OSA and intracranial hypertension (ICH), it may be prudent to screen all patients with spontaneous CSF rhinorrhea for symptoms of OSA as well as for ICH, and vice versa.

Our findings suggest that FESS, particularly with larger antrostomies, improves topical drug delivery, and that certain particle sizes improve this delivery. Further research is needed to contextualise these findings with other post-surgical effects.