title: Endoscopically assisted strabismus surgery.
abstract: BACKGROUND
  Strabismus surgery involving open exploration of the posterior orbit is difficult. Exploration is sometimes avoided by considering alternative procedures (transposition and weakening other muscles). Although the use of endoscopic sinus surgery (ESS) to retrieve medial rectus (MR) muscles lost in the posterior orbit has been described, the use of an endoscopic approach to the posterior orbit in elective strabismus surgery has never been reported.
  
  
  METHODS
  A patient with thyroid orbitopathy had severe bilateral restrictive strabismus with bilateral esohypotropia, rendering him functionally blind. The MR was inaccessible via the anterior approach. We describe a transnasal endoscopic approach to the posterior orbit where the MR was identified, sectioned, and reattached to the globe. We also describe two other patients who had endoscopic posterior orbit exploration after ESS-related MR injury.
  
  
  RESULTS
  In patient 1, repositioning of the medial rectus muscles facilitated follow-up conventional strabismus surgery and dramatically improved ocular alignment. In patient 2, the medial rectus muscle was severely disrupted. A temporary traction suture was placed endoscapically. Follow-up transposition strabimus resulted in satisfactory alignment. In patient 3, endoscopic exploration and freeing of adhesions was done in anticipation of follow-up strabismus surgery.
  
  
  CONCLUSIONS
  These cases illustrate the expanding frontiers of ESS. The endoscopic approach to the posterior orbit allows enhanced posterior orbit access in elective strabismus surgery and posttraumatic exploration of the MR.
authors.affiliation: Department of Ophthalmology, McGill University Health Center, Centre Hospitalier de l'Université de Montreal, Montreal, Canada. michael.flanders@mcgill.ca
authors.forename: Michael
authors.initials: M
authors.lastname: Flanders
authors.forename: Siew Yoong
authors.initials: SY
authors.lastname: Hwang
authors.forename: Saeed
authors.initials: S
authors.lastname: Al-Ghamdi
authors.forename: François
authors.initials: F
authors.lastname: Codère
authors.forename: Martin
authors.initials: M
authors.lastname: Desrosiers
mesh_terms: D004724:Endoscopy / Q000379:methods; D005260:Female; D006111:Graves Disease / Q000150:complications; D006801:Humans; D008297:Male; D008875:Middle Aged; D009801:Oculomotor Muscles / Q000000981:diagnostic imaging / Q000473:pathology; D013285:Strabismus / Q000000981:diagnostic imaging / Q000601:surgery*; D013537:Sutures; D014057:Tomography, X-Ray Computed