title: Endoscopic anterior ethmoidal artery ligation: a cadaver study.
abstract: OBJECTIVE
  The objective of this study was to investigate the radiologic and endoscopic anatomy of the anterior ethmoidal canal (AEC) and feasibility of endoscopic ligation of the anterior ethmoidal artery (AEA).
  
  
  METHODS
  The authors conducted a prospective analysis of computed tomography (CT) of the paranasal sinuses and endoscopic cadaver dissection.
  
  
  METHODS
  Twenty-two cadaver heads had CT scans of the paranasal sinuses. The height of the lateral lamella of the cribriform plate was calculated and staged according to the Keros staging system. The presence of a bony mesentery, distance from AEC to the skull base, and dehiscence of the AEC were documented. Forty-four dissections were performed, the AECs identified, and AEA ligation attempted.
  
  
  RESULTS
  The mean height of the lateral lamella was 5.4 mm on the right and 4.7 mm on the left. In all cadaver heads with asymmetry, the right lateral lamella was longer (P<.005). A Keros type 1 pattern was seen in 23%, type 2 in 50%, and type 3 in 27%. Thirty-six percent of AECs were in a bony mesentery. AEC distance from the skull base was greater on the right (P<.009). A longer lateral lamella was correlated with the artery being in a mesentery. Sixteen percent of the AECs were dehiscent. Sixty-six percent of AEAs were unable to be clipped. Twenty percent were clipped effectively, all in a mesentery. In 14%, the AEA was not effectively clipped.
  
  
  CONCLUSIONS
  Endoscopic AEA ligation may be possible in some patients. The AEA should be in a mesentery for an effective clip to be placed and be associated with a dehiscence of the AEC. If the lateral lamella is classified as Keros grade 2 or 3, it is likely the AEC will be found in a mesentery.
authors.affiliation: Department of Surgery, Otolaryngology, Head and Neck Surgery, University of Adelaide and Flinders University, Adelaide, South Australia.
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Floreani
authors.forename: Salil B
authors.initials: SB
authors.lastname: Nair
authors.forename: Michael C
authors.initials: MC
authors.lastname: Switajewski
authors.forename: Peter-John
authors.initials: PJ
authors.lastname: Wormald
mesh_terms: D001158:Arteries / Q000033:anatomy & histology; D002102:Cadaver; D004844:Epistaxis / Q000628:therapy; D005005:Ethmoid Sinus / Q000098:blood supply* / Q000000981:diagnostic imaging; D016558:Hemostasis, Endoscopic / Q000379:methods*; D006801:Humans; D066298:In Vitro Techniques; D008026:Ligation; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed