title: High-resolution computed tomography analysis of the frontal sinus ostium: a pilot study.
abstract: OBJECTIVE
  Identification and exposure of the frontal sinus recess (FSR) during endoscopic sinus surgery (ESS) are challenging due to the variable anatomy, the narrow opening of the frontal sinus ostium (FSO), and the proximity of vital anatomic structures. Hence, a strong understanding of frontal sinus anatomy is required to prevent intracranial entry. Consistent and easily identifiable landmarks and measurements could assist safe entry into the FSO. In this study, we determine the distances from the columella and anterior nasal spine (ANS) to the nasofrontal beak (NFB) and anterior skull base (ASB) using high-resolution computed tomography (HRCT) scans.
  
  
  METHODS
  A radiographic analysis was performed at a tertiary care medical center. Measurements from the ANS to the NFB and ASB, and from the columella to the NFB and ASB were made using sagittal HRCT. Thirty-two HRCT scans were analyzed by three observers, and the mean distances and standard deviations were calculated.
  
  
  RESULTS
  The mean distance from the ANS to the NFB was 52.3±3.4mm in men and 47.7±3.5mm in women (p<0.0001). Mean distance from the ANS to the ASB was 61.8±4.1mm in men and 56.5±4.1mm in women (p<0.0001). Mean distance from the columella to the NFB was 58.9±2.3mm in men and 53.0±3.3mm in women (p<0.0001), and from the columella to the ASB was 67.9±3.7 mm in men and 61.3±4.1mm in women (p<0.0001).
  
  
  CONCLUSIONS
  While performing FSR exposure in ESS, it is recommended to stay a distance of less than 66.9 mm in men and 60.6mm in women from the columella to minimize intracranial complications.
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, NJ 07103, USA. jean.anderson.eloy@gmail.com
authors.forename: Jean Anderson
authors.initials: JA
authors.lastname: Eloy
authors.forename: David M
authors.initials: DM
authors.lastname: Neskey
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Vivero
authors.forename: Jose W
authors.initials: JW
authors.lastname: Ruiz
authors.forename: Osamah J
authors.initials: OJ
authors.lastname: Choudhry
authors.forename: Roy R
authors.initials: RR
authors.lastname: Casiano
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005626:Frontal Sinus / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009296:Nasal Cavity / Q000000981:diagnostic imaging; D010256:Paranasal Sinuses / Q000000981:diagnostic imaging; D010865:Pilot Projects; D019291:Skull Base / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed / Q000379:methods; D055815:Young Adult