title: The impact of endoscopic sinus surgery on paranasal physiology in simulated sinus cavities.
abstract: Surgery improves symptoms for the majority of chronic rhinosinusitis (CRS) patients; however, physiological changes in the sinus cavities remain poorly characterized. Direct measurement of changes in airflow, pressure, temperature, humidity, and intranasal spray distribution following surgery is technically challenging. Accordingly, we have used computational fluid dynamic modeling to quantify how these parameters change postoperatively.
  
  
  
  Computed tomography images from a normal control, a patient with CRS preoperatively and postoperatively, and a patient following an endoscopic Lothrop procedure (ELP) were used to create 4 three-dimensional models of the sinus cavities. Changes in physiologic parameters and topical drug distribution were modeled (inhaled air at 16°C and 10% humidity) at the maxillary ostium, frontal recess, and sphenoid ostium.
  
  
  
  Large differences were seen between models. Following surgery, the maxillary ostia were found on average to be cooler (by 2.4°C), with an increased airflow (0.26 m/second; from 0 m/second), and a 9% reduction in absolute humidity. Sphenoid ostial parameters followed a similar trend. Significant changes in frontal recess physiology were seen following ELP in which the recess was 4.2°C cooler, had increased airflow (0.76 m/second) and a 17% reduction in absolute humidity. Topical drug distribution increased with surgery, particularly after ELP.
  
  
  
  Surgery changes the geometry and physiology of the paranasal sinuses. These changes are likely to have an impact on wound healing, mucociliary function, and microbial ecology in postoperative cavities. Application of this model to further understand the effects of surgery may help to optimize surgical techniques and improve topical drug delivery.
authors.affiliation: Department of Surgery, The University of Auckland, Auckland, New Zealand.
authors.forename: Ravi
authors.initials: R
authors.lastname: Jain
authors.affiliation: Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand.
authors.forename: Haribalan
authors.initials: H
authors.lastname: Kumar
authors.affiliation: Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand.
authors.forename: Merryn
authors.initials: M
authors.lastname: Tawhai
authors.affiliation: Department of Surgery, The University of Auckland, Auckland, New Zealand.
authors.forename: Richard
authors.initials: R
authors.lastname: Douglas
mesh_terms: D002908:Chronic Disease; D003198:Computer Simulation; D004724:Endoscopy; D006801:Humans; D008953:Models, Anatomic; D059085:Nasal Sprays; D010256:Paranasal Sinuses / Q000000981:diagnostic imaging / Q000378:metabolism / Q000502:physiology* / Q000601:surgery*; D012220:Rhinitis / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000503:physiopathology / Q000601:surgery; D012852:Sinusitis / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000503:physiopathology / Q000601:surgery; D014057:Tomography, X-Ray Computed
chemical_list: D059085:Nasal Sprays
keywords: computer simulation; humidity; intranasal drug administration; intranasal surgery; paranasal sinuses; physiology; pressure; respiratory airflow; sinusitis; temperature