title: Inferior oblique muscle fixation to the orbital wall: a profound weakening procedure.
abstract: BACKGROUND
  Recurrent or persistent inferior oblique overaction may occur after inferior oblique (IO) recession or anterior transposition. IO nasal and temporal myectomy and anterior-nasal transposition may result in undesirable IO palsy, exotropia, incyclotorsion, or limitation of elevation. Previous studies have shown that a rectus extraocular muscle may be profoundly weakened if the muscle insertion is reattached to adjacent orbital periosteum. We describe a reversible profound weakening surgical procedure of the IO muscle.
  
  
  METHODS
  A total of 10 consecutive subjects with V-pattern strabismus and/or IO overaction underwent IO orbital fixation procedure by attaching its insertion to the periosteum of the lateral orbital wall. One subject was not included because short follow-up. Five subjects with persistent IO overaction after IO anterior transposition underwent bilateral IO orbital wall fixation. Four subjects with no previous IO surgery underwent unilateral IO orbital wall fixation; 3 of these 4 subjects had superior oblique palsy with a large vertical deviation in primary position and 1 had a V pattern with asymmetric IO overaction.
  
  
  RESULTS
  V pattern significantly improved from 22(Delta) preoperatively to 7(Delta) postoperatively (p = 0.002). IO overaction improved from 2.5 (range, + 1.5 to + 4) to 0.1 (range, -2 to +3) postoperatively (p < 0.001). Six of 9 subjects had no residual overelevation in adduction postoperatively. Unilateral IO orbital fixation corrected 7(Delta) of vertical deviation in the primary position and 23(Delta) in adduction. Mean postoperative follow-up was 5 months.
  
  
  CONCLUSIONS
  IO orbital fixation has a profound weakening effect on the IO muscle. Advantages of this procedure include reversibility and that it can be converted into another form of weakening procedure, if required.
authors.affiliation: Jules Stein Eye Institute, University of California-Los Angeles, 100 Stein Plaza, Los Angeles, CA 90024, USA.
authors.forename: Noa
authors.initials: N
authors.lastname: Ela-Dalman
authors.forename: Federico G
authors.initials: FG
authors.lastname: Velez
authors.forename: Joost
authors.initials: J
authors.lastname: Felius
authors.forename: David R
authors.initials: DR
authors.lastname: Stager
authors.forename: Arthur L
authors.initials: AL
authors.lastname: Rosenbaum
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005133:Eye Movements; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D009801:Oculomotor Muscles / Q000503:physiopathology / Q000601:surgery*; D009915:Orbit / Q000601:surgery*; D012189:Retrospective Studies; D013285:Strabismus / Q000503:physiopathology / Q000601:surgery*; D013536:Suture Techniques; D016896:Treatment Outcome