title: A novel use of a landmark to avoid injury of the anterior ethmoidal artery during endoscopic sinus surgery.
abstract: BACKGROUND
  The aim of this study was to describe and correlate radiographically the anterior ethmoidal artery (AEA) to useful endoscopic surgical landmarks, such as the nasal beak (NB), nasal crest (NC), and axilla of the middle turbinate, because these are commonly encountered during endoscopic sinus surgery and skull base surgery.
  
  
  METHODS
  A retrospective review and software analysis was performed by three independent observers. Measurements of distance and angulation from the AEA to the NC, NB, and axilla of the middle turbinate were performed. A total of 138 unique computed tomography (CT) scans performed at a university tertiary care center were evaluated.
  
  
  RESULTS
  The average age of the patients whose scans were analyzed was 50.5 (range, 17-90 years) years of age. The gender distribution was 61 male and 89 female patients. After comparing the measurements to the three landmarks noted, it was determined that the NB had the most interpatient concordance and the least interobserver variability. The average distance between the NB and the AEA as it penetrates the lamina papyracea is 2.34 cm (variance, 0.07) at an angle of 45.21° from the Frankfurt horizontal line.
  
  
  CONCLUSIONS
  The real advantage of this novel use of the NB as a landmark to identify the AEA is that it is easy to use, unobtrusive, and is not time-consuming. This relationship between the NB and the AEA is consistent across genders and ethnicities and is more valuable than others presented previously, which may be more variable.
authors.affiliation: Department of Otolaryngology, University of Texas Medical Branch, Galveston, Texas, USA. fgpernas@utmb.edu
authors.forename: Francisco G
authors.initials: FG
authors.lastname: Pernas
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Coughlin
authors.forename: Sharon E
authors.initials: SE
authors.lastname: Hughes
authors.forename: Roy
authors.initials: R
authors.lastname: Riascos
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Maeso
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D035262:Cranial Fossa, Anterior; D004724:Endoscopy; D005005:Ethmoid Sinus / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008438:Maxillary Artery / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D008875:Middle Aged; D019106:Postoperative Hemorrhage / Q000209:etiology / Q000517:prevention & control*; D019291:Skull Base / Q000601:surgery*; D014057:Tomography, X-Ray Computed