title: Anterior and nasal transposition of the inferior oblique muscles.
abstract: BACKGROUND
  When performing anterior transposition of the inferior oblique (IO) muscle, placement of the posterior suture close to the lateral border of insertion of the inferior rectus (IR) muscle decreases the incidence of antielevation syndrome (AES). We hypothesized that placement of the suture nasal to the IR muscle insertion will convert the IO muscle into an intorter and depressor. Here we present the first series of results obtained with a new procedure for the treatment of elevation in adduction with extorsion and abnormal head postures.
  
  
  METHODS
  Twenty patients with IO muscle overaction, superior oblique (SO) muscle palsy, absent SO muscles, AES, or Duane syndrome were studied. Before surgery, each patient showed at least one, but often more, of the following signs: elevation in adduction, exotropia (XT) in up gaze, abnormal head posture, and extorsion. Each underwent anterior and nasal transposition (ANT) of the IO muscle, with the new insertion typically 2 mm nasal and 2 mm posterior to the nasal border of the IR muscle insertion.
  
  
  RESULTS
  Large improvements in ocular alignment, extorsion, and head posture were found in most patients. However, a poor result was noted in a patient with Y-pattern XT, who developed a mild amount of comitant XT after an extreme degree of ANT (4 mm nasal and 3 mm anterior to the nasal border of the IR muscle insertion). In Duane syndrome, ANT corrects upshoot, but downshoot may get worse. Mersilene permanent sutures, rather than dissolving suture materials, are recommended to avoid postoperative retraction of muscle fibers.
  
  
  CONCLUSIONS
  ANT converts the IO muscle into an intorter and tonic depressor and can significantly improve elevation in adduction. This procedure seems particularly useful in patients with severe or recurrent congenital and acquired SO palsies, particularly as a secondary procedure. Extreme ANT may induce exotropia in the primary position.
authors.affiliation: Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, USA.
authors.forename: David R
authors.initials: DR
authors.lastname: Stager
authors.forename: George R
authors.initials: GR
authors.lastname: Beauchamp
authors.forename: Weldon W
authors.initials: WW
authors.lastname: Wright
authors.forename: Joost
authors.initials: J
authors.lastname: Felius
authors.forename: David
authors.initials: D
authors.lastname: Stager
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D004370:Duane Retraction Syndrome / Q000601:surgery*; D005099:Exotropia / Q000601:surgery; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D018908:Muscle Weakness / Q000601:surgery*; D009135:Muscular Diseases / Q000601:surgery*; D009801:Oculomotor Muscles / Q000002:abnormalities* / Q000637:transplantation*; D013508:Ophthalmologic Surgical Procedures / Q000009:adverse effects; D009886:Ophthalmoplegia / Q000209:etiology / Q000601:surgery*; D010865:Pilot Projects; D012086:Reoperation; D012163:Retinal Detachment / Q000601:surgery; D014182:Transplantation, Autologous