title: Artifacts of measuring during strabismus surgery.
abstract: Several different artifacts can induce errors in measurements obtained during strabismus surgery. Fixating the severed rectus muscle stump with forceps during strabismus surgery can result in a temporary anterior displacement of the insertion. This may result in inaccuracies in determining the site to which the muscle is to be recessed. This displacement was quantified in a prospective masked manner and was found in some patients to result in as much as 1 mm of error. It can be prevented by measuring the recession prior to fixating the insertion stump with forceps; however, it cannot always be prevented by measuring from the limbus, which also introduces other artifacts due to geometric principles. An "advancement effect" occurs during a rectus muscle recession due to the mechanics of suture placement in the muscle. It was quantified in a masked manner and found to be approximately .5 mm in most cases. A "V" shaped deformity of the insertion stump may occur immediately adjacent to the forceps. This deformity frequently distorts the insertion by as much as several millimeters.
authors.affiliation: University of Wisconsin Clinical Science Center, Madison 53792.
authors.forename: B J
authors.initials: BJ
authors.lastname: Kushner
authors.forename: M W
authors.initials: MW
authors.lastname: Preslan
authors.forename: M
authors.initials: M
authors.lastname: Vrabec
mesh_terms: D006801:Humans; D008488:Medical Illustration; D009885:Ophthalmology / Q000379:methods*; D013285:Strabismus / Q000473:pathology / Q000601:surgery*; D013536:Suture Techniques