title: Clinical factors underlying a single surgery or repetitive surgeries to treat superior oblique muscle palsy.
abstract: The purpose of this study is to know clinical factors underlying either a single surgery or repetitive surgeries, required to treat superior oblique muscle palsy. Retrospective review was made on 246 consecutive patients with idiopathic (n = 212) or acquired (n = 34) superior oblique muscle palsy who underwent surgeries in 8 years at one institution. Idiopathic palsy included congenital and decompensated palsies while acquired palsy included traumatic and ischemic palsies. Clinical factors, compared between groups with a single surgery (n = 203) and two or more surgeries (n = 43), were surgical methods, sex, age at surgery, horizontal, vertical, and cyclotorsional deviations, and stereopsis at near fixation. Inferior oblique muscle recession on paretic side was chosen in about 60% of the single-surgery and repetitive-surgery group as an initial surgery, followed by inferior rectus muscle recession on non-paretic side. The age at surgery was significantly older, vertical and cyclotorsional deviations were significantly larger in the repetitive-surgery group, compared with the single-surgery group (P = 0.01, P < 0.001, P = 0.02, Mann-Whitney U-test, respectively). The 95% confidence interval of vertical deviations was 15-17 prism diopters in the single-surgery group and 23-28 prism diopters in the repetitive surgery group. Significant differences in vertical deviations were replicated also in subgroups of patients with either idiopathic or acquired palsy. In conclusions, the 95% confidence interval of vertical deviations, determined by alternate prism and cover test, would be used as a common benchmark for predicting either a single surgery or repetitive surgeries, required to treat idiopathic and acquired superior oblique muscle palsy, in the process of obtaining the informed consent.
authors.affiliation: Department of Ophthalmology, Okayama University Medical School and Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Kana
authors.initials: K
authors.lastname: Aoba
authors.affiliation: Department of Ophthalmology, Okayama University Medical School and Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Matsuo
authors.affiliation: Department of Ophthalmology, Okayama University Medical School and Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Hamasaki
authors.affiliation: Department of Ophthalmology, Okayama University Medical School and Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan ; Present address: Department of Ophthalmology, Kawasaki Medical School-Affiliated Kawasaki Hospital, Okayama, Japan.
authors.forename: Kayoko
authors.initials: K
authors.lastname: Hasebe
keywords: 95% confidence interval; Cyclotorsional deviation (torsion); Inferior oblique muscle recession; Inferior rectus muscle recession; Informed consent; Repetitive surgeries; Superior oblique muscle palsy; Superior rectus muscle recession; Surgery; Vertical deviation