title: The efficacy of superior oblique Z-tenotomy in the treatment of overdepression in adduction (superior oblique overaction).
abstract: BACKGROUND
  To evaluate the efficacy of superior oblique Z-tenotomy in the treatment of overdepression in adduction (superior oblique overaction) with respect to collapse of A-pattern strabismus and normalization of versions.
  
  
  METHODS
  The medical records of patients who underwent bilateral superior oblique Z-tenotomy for mild to moderate overdepression in adduction and A-pattern strabismus between June 2004 and August 2010 were retrospectively reviewed. Surgical indications included mild to moderate overdepression in adduction (+2 to 3) and an A pattern of 10(Δ) to 40(Δ) between upgaze and downgaze. A monopolar electrode microdissection needle was used to make two tenotomies, 60% to 80% in width and 8 mm apart, perpendicular to the axes of the tendon in opposite directions. Surgical success included a postoperative A pattern of ≤10(Δ) and overdepression in adduction of ≤1.
  
  
  RESULTS
  A total of 20 patients (mean age, 9.8 years; age range, 3-34) underwent bilateral superior oblique Z-tenotomy during the study period: 2 patients (10%) with esotropia and 18 with exotropia (90%). Average decrease in pattern was 16(Δ) (range, 0(Δ)-32.5(Δ)). Success rate for pattern collapse was 78%, with resolution of overdepression in adduction of 90%.
  
  
  CONCLUSIONS
  Z-tenotomy of the superior oblique tendon collapsed A-pattern strabismus and normalized versions.
authors.affiliation: Vanderbilt Eye Institute, Vanderbilt University, Nashville, Tennessee, USA. brooksd@slhs.org
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Brooks
authors.forename: David G
authors.initials: DG
authors.lastname: Morrison
authors.forename: Sean P
authors.initials: SP
authors.lastname: Donahue
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004948:Esotropia / Q000503:physiopathology / Q000601:surgery*; D005099:Exotropia / Q000503:physiopathology / Q000601:surgery*; D005133:Eye Movements / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009801:Oculomotor Muscles / Q000503:physiopathology / Q000601:surgery*; D012189:Retrospective Studies; D013710:Tendons / Q000601:surgery*; D058971:Tenotomy / Q000379:methods*; D016896:Treatment Outcome; D015348:Vision, Binocular / Q000502:physiology; D055815:Young Adult