title: Adjustable Bilateral Superior Oblique Tendon Advancement for Bilateral Fourth Nerve Palsy.
abstract: OBJECTIVE
  Bilateral fourth nerve palsy may be symmetric or asymmetric with combined vertical and excylotropic deviations and so there may be an advantage to independent adjustment of vertical and torsional components. We report a surgical technique that allows such independent adjustment.
  
  
  METHODS
  Retrospective interventional case series.
  
  
  METHODS
  Fifteen patients, aged 17-73 years, underwent adjustable bilateral superior oblique tendon advancements for bilateral fourth nerve palsy: 11 symmetric (≤2 prism diopters [pd] hyperdeviation in straight-ahead gaze) and 4 asymmetric. Motor alignment was assessed with double Maddox rods and prism and alternate cover tests preoperatively, pre- and postadjustment, and 6 weeks postoperatively.
  
  
  RESULTS
  Preoperative torsion ranged from 7 to 30 degrees excyclotropia (mean 17 ± 7 degrees) and hyperdeviation from 0 to 10 pd. Preadjustment torsion ranged from 5 degrees excyclotropia to 40 degrees incyclotropia, and hyperdeviation from 0 to 8 pd. Twelve of the 15 patients (80%) were adjusted to a target of 0 pd hyperphoria and 10 degrees incyclotropia (actual mean 9 degrees incyclotropia, range 2-13 degrees incyclotropia). At 6 weeks postoperatively there was expected excyclodrift (to mean 4 degrees excyclotropia, range 0 degrees incyclotropia to 15 degrees excyclotropia), but 13 (87%) had 5 degrees or less excyclotropia and 14 (93%) had 2 pd or less hyperdeviation. Mean torsional correction from preoperative to preadjustment was 31 ± 14 degrees (P < .0001), and from preoperative to 6 weeks was 13 ± 6 degrees (P < .0001).
  
  
  CONCLUSIONS
  Adjustable bilateral superior oblique tendon advancement allows independent control of torsional and vertical components of the deviation, and therefore may be useful in cases of bilateral superior oblique palsy.
authors.affiliation: Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota.
authors.forename: Bashar M
authors.initials: BM
authors.lastname: Bata
authors.affiliation: Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota.
authors.forename: David A
authors.initials: DA
authors.lastname: Leske
authors.affiliation: Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota. Electronic address: holmes.jonathan@mayo.edu.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Holmes
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005133:Eye Movements / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009801:Oculomotor Muscles / Q000503:physiopathology / Q000601:surgery*; D013508:Ophthalmologic Surgical Procedures / Q000379:methods*; D011184:Postoperative Period; D013285:Strabismus / Q000209:etiology / Q000503:physiopathology / Q000601:surgery*; D013710:Tendons / Q000601:surgery*; D013997:Time Factors; D020432:Trochlear Nerve Diseases / Q000150:complications / Q000503:physiopathology / Q000601:surgery*; D015348:Vision, Binocular / Q000502:physiology*; D055815:Young Adult